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WO2020062061A1 - Réduction de complexité pour décodage de liste d'annulation séquentielle de codes polaires - Google Patents

Réduction de complexité pour décodage de liste d'annulation séquentielle de codes polaires Download PDF

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Publication number
WO2020062061A1
WO2020062061A1 PCT/CN2018/108422 CN2018108422W WO2020062061A1 WO 2020062061 A1 WO2020062061 A1 WO 2020062061A1 CN 2018108422 W CN2018108422 W CN 2018108422W WO 2020062061 A1 WO2020062061 A1 WO 2020062061A1
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WIPO (PCT)
Prior art keywords
decoding
decoding paths
edc
list size
paths
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Ceased
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PCT/CN2018/108422
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English (en)
Inventor
Jian Li
Changlong Xu
Liangming WU
Kai Chen
Jing Jiang
Hao Xu
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Qualcomm Inc
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Qualcomm Inc
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Priority to PCT/CN2018/108422 priority Critical patent/WO2020062061A1/fr
Publication of WO2020062061A1 publication Critical patent/WO2020062061A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/004—Arrangements for detecting or preventing errors in the information received by using forward error control
    • H04L1/0056—Systems characterized by the type of code used
    • H04L1/0057—Block codes
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/004—Arrangements for detecting or preventing errors in the information received by using forward error control
    • H04L1/0045—Arrangements at the receiver end
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/004—Arrangements for detecting or preventing errors in the information received by using forward error control
    • H04L1/0056—Systems characterized by the type of code used
    • H04L1/0061—Error detection codes
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/12—Arrangements for detecting or preventing errors in the information received by using return channel
    • H04L1/16—Arrangements for detecting or preventing errors in the information received by using return channel in which the return channel carries supervisory signals, e.g. repetition request signals
    • H04L1/18—Automatic repetition systems, e.g. Van Duuren systems
    • H04L1/1812—Hybrid protocols; Hybrid automatic repeat request [HARQ]

Definitions

  • the following relates generally to wireless communications, and more specifically to dynamic list size reduction for decoding polar codes.
  • Wireless communications systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power) .
  • Examples of such multiple-access systems include fourth generation (4G) systems such as Long Term Evolution (LTE) systems, LTE-Advanced (LTE-A) systems, or LTE-A Pro systems, and fifth generation (5G) systems which may be referred to as New Radio (NR) systems.
  • 4G systems such as Long Term Evolution (LTE) systems, LTE-Advanced (LTE-A) systems, or LTE-A Pro systems
  • 5G systems which may be referred to as New Radio (NR) systems.
  • a wireless multiple-access communications system may include a number of base stations or network access nodes, each simultaneously supporting communication for multiple communication devices, which may be otherwise known as user equipment (UE) .
  • UE user equipment
  • wireless devices may utilize error-correcting codes (e.g., polar codes) for encoding and decoding transmissions, such as physical downlink control channel (PDCCH) transmissions.
  • Decoding complexity may vary based on the number of information bits being decoded. For example, codewords with large numbers of information bits may result in greater decoding complexity than codewords with small numbers of information bits.
  • EDC distributed error detection check
  • Early termination techniques based on distributed error detection check (EDC) bits for decoding a polar coded transmission may achieve a reduction in the decoding complexity. However, performing early termination may not significantly reduce decoding complexity for codewords with large numbers of information bits. As such, early termination is not effective for reducing decoding complexity for decoding polar codes for all ranges of encoded information bits.
  • the described techniques relate to improved methods, systems, devices, and apparatuses that support dynamic list size reduction for decoding polar codes.
  • the described techniques provide for a reduction in decoding complexity for polar encoded codewords (e.g., especially codewords with large numbers of information bits) .
  • a device monitoring for decoding candidates for a polar encoded codeword may perform a decoding process using dynamic list size reduction.
  • the device may determine path metrics for a first set of decoding paths for a given decoding candidate over a first subset of bit channels. The number of paths in this first set of decoding paths may correspond to a first list size of the decoding process.
  • the decoder may perform an EDC operation for the first set of decoding paths using respective values or sets of values for the EDC bit or bits.
  • the decoder may prune decoding paths that fail the EDC operation and may reduce, during the decoding process, the effective list size for the decoding process. For example, the decoder may determine a second list size for the decoding process, where the second list size is calculated by subtracting the number of decoding paths that fail the EDC operation from the first list size.
  • the device or the decoder may determine whether to perform the dynamic list size reduction based on a threshold or a comparison of path metrics for certain decoding path candidates.
  • the decoder may continue the decoding process using the reduced list size (e.g., the second list size) , achieving a reduction in the decoding complexity for the polar code.
  • a method of wireless communications may include receiving a decoding candidate associated with a codeword, the codeword corresponding to a set of information bits encoded using a polar code, and performing a decoding process on the decoding candidate.
  • the decoding process may include determining path metrics for each of a first set of decoding paths over a first subset of bit channels of the polar code, where the first set of decoding paths corresponds to a first list size, identifying an EDC bit of the set of information bits, performing an EDC operation on the first set of decoding paths using respective values of the EDC bit, and determining path metrics for each of a second set of decoding paths over a second subset of bit channels of the polar code, where the second set of decoding paths corresponds to a second list size, and where the second list size is determined based on the first list size and a number of decoding paths of the first set of decoding paths that fail the EDC operation.
  • the apparatus may include a processor, memory in electronic communication with the processor, and instructions stored in the memory.
  • the instructions may be executable by the processor to cause the apparatus to receive a decoding candidate associated with a codeword, the codeword corresponding to a set of information bits encoded using a polar code, and perform a decoding process on the decoding candidate.
  • the instructions to perform the decoding process may be further executable by the processor to determine path metrics for each of a first set of decoding paths over a first subset of bit channels of the polar code, where the first set of decoding paths corresponds to a first list size, identify an EDC bit of the set of information bits, perform an EDC operation on the first set of decoding paths using respective values of the EDC bit, and determine path metrics for each of a second set of decoding paths over a second subset of bit channels of the polar code, where the second set of decoding paths corresponds to a second list size, and where the second list size is determined based on the first list size and a number of decoding paths of the first set of decoding paths that fail the EDC operation.
  • the apparatus may include means for receiving a decoding candidate associated with a codeword, the codeword corresponding to a set of information bits encoded using a polar code, and means for performing a decoding process on the decoding candidate.
  • the means for performing the decoding process may further include means for determining path metrics for each of a first set of decoding paths over a first subset of bit channels of the polar code, where the first set of decoding paths corresponds to a first list size, identifying an EDC bit of the set of information bits, performing an EDC operation on the first set of decoding paths using respective values of the EDC bit, and determining path metrics for each of a second set of decoding paths over a second subset of bit channels of the polar code, where the second set of decoding paths corresponds to a second list size, and where the second list size is determined based on the first list size and a number of decoding paths of the first set of decoding paths that fail the EDC operation.
  • a non-transitory computer-readable medium storing code for wireless communications is described.
  • the code may include instructions executable by a processor to receive a decoding candidate associated with a codeword, the codeword corresponding to a set of information bits encoded using a polar code, and perform a decoding process on the decoding candidate.
  • the instructions executable to perform the decoding process may be further executable to determine path metrics for each of a first set of decoding paths over a first subset of bit channels of the polar code, where the first set of decoding paths corresponds to a first list size, identify an EDC bit of the set of information bits, perform an EDC operation on the first set of decoding paths using respective values of the EDC bit, and determine path metrics for each of a second set of decoding paths over a second subset of bit channels of the polar code, where the second set of decoding paths corresponds to a second list size, and where the second list size is determined based on the first list size and a number of decoding paths of the first set of decoding paths that fail the EDC operation.
  • the decoding process further may include operations, features, means, or instructions for identifying a second EDC bit of the set of information bits, performing a second EDC operation on the second set of decoding paths using respective values of the second EDC bit, identifying that all decoding paths of the second set of decoding paths fail the second EDC operation, and terminating the decoding process based on the identifying that all the decoding paths of the second set of decoding paths fail the second EDC operation.
  • the decoding process further may include operations, features, means, or instructions for identifying a second EDC bit of the set of information bits, performing a second EDC operation on the second set of decoding paths using respective values of the second EDC bit, and determining path metrics for each of a third set of decoding paths over third subset of bit channels of the polar code, where the third set of decoding paths corresponds to a third list size, and where the third list size may be determined based on the second list size and a number of decoding paths of the second set of decoding paths that fail the second EDC operation.
  • Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining whether to reduce a list size for the decoding process from the first list size to the second list size based on a threshold value.
  • the threshold value may include a threshold downlink control information (DCI) size.
  • determining whether to reduce the list size for the decoding process further may include operations, features, means, or instructions for determining an expected DCI size for the decoding candidate and comparing the expected DCI size for the decoding candidate to the threshold DCI size, where the list size for the decoding process may be reduced if the expected DCI size for the decoding candidate may be larger than the threshold DCI size.
  • the threshold value may include a threshold performance loss value.
  • determining whether to reduce the list size for the decoding process further may include operations, features, means, or instructions for storing a lookup table in memory, the lookup table including estimated performance loss values for the decoding process for different combinations of numbers of information bits and codeword lengths, identifying an estimated performance loss value from the lookup table based on an expected number of information bits and expected codeword length for the decoding candidate, and comparing the identified estimated performance loss value to the threshold performance loss value, where the list size for the decoding process may be reduced if the identified estimated performance loss value may be less than the threshold performance loss value.
  • the threshold value may be preconfigured or may be received in a configuration message.
  • Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for storing a lookup table in memory, the lookup table including a list size reduction enablement value for the decoding process for different combinations of numbers of information bits and codeword lengths and determining whether to reduce a list size for the decoding process from the first list size to the second list size based on the stored lookup table.
  • the decoding process further may include operations, features, means, or instructions for comparing one or more path metrics for decoding paths of the first set of decoding paths that fail the EDC operation with one or more path metrics for decoding paths of the first set of decoding paths that pass the EDC operation and determining to reduce a list size for the decoding process from the first list size to the second list size based on the comparing.
  • comparing the one or more path metrics for the decoding paths of the first set of decoding paths that fail the EDC operation with the one or more path metrics for the decoding paths of the first set of decoding paths that pass the EDC operation may include operations, features, means, or instructions for comparing a minimum path metric for the decoding paths of the first set of decoding paths that fail the EDC operation with a minimum path metric for the decoding paths of the first set of decoding paths that pass the EDC operation.
  • determining to reduce the list size for the decoding process may include operations, features, means, or instructions for determining to reduce the list size for the decoding process if the minimum path metric for the decoding paths of the first set of decoding paths that pass the EDC operation are less than the minimum path metric for the decoding paths of the first set of decoding paths that fail the EDC operation.
  • comparing the one or more path metrics for the decoding paths of the first set of decoding paths that fail the EDC operation with the one or more path metrics for the decoding paths of the first set of decoding paths that pass the EDC operation may include operations, features, means, or instructions for comparing a minimum path metric for the decoding paths of the first set of decoding paths that fail the EDC operation with a minimum path metric for the decoding paths of the first set of decoding paths that pass the EDC operation.
  • determining to reduce the list size for the decoding process may include operations, features, means, or instructions for determining to reduce the list size for the decoding process if a difference between the minimum path metric for the decoding paths of the first set of decoding paths that fail the EDC operation and the minimum path metric for the decoding paths of the first set of decoding paths that pass the EDC operation are greater than a path metric difference threshold.
  • identifying the EDC bit of the set of information bits may include operations, features, means, or instructions for identifying a set of EDC bits of the set of information bits and performing the EDC operation on the first set of decoding paths may include operations, features, means, or instructions for performing the EDC operation on the first set of decoding paths using respective sets of values of the set of EDC bits.
  • the first list size may be based on a capability of a successive cancellation list (SCL) decoder performing the decoding process.
  • the decoding candidate includes a physical downlink control channel (PDCCH) transmission and the set of information bits includes DCI.
  • the EDC operation includes a cyclic redundancy check (CRC) operation.
  • FIGs. 1 and 2 illustrate examples of wireless communications systems that support dynamic list size reduction for decoding polar codes in accordance with aspects of the present disclosure.
  • FIG. 3 illustrates an example of a device that supports dynamic list size reduction for decoding polar codes in accordance with aspects of the present disclosure.
  • FIG. 4 illustrates an example of a dynamic list size reduction procedure for decoding polar codes in accordance with aspects of the present disclosure.
  • FIG. 5 illustrates an example of a process flow that supports dynamic list size reduction for decoding polar codes in accordance with aspects of the present disclosure.
  • FIGs. 6 and 7 show block diagrams of devices that support dynamic list size reduction for decoding polar codes in accordance with aspects of the present disclosure.
  • FIG. 8 shows a block diagram of a dynamic list size decoder that supports dynamic list size reduction for decoding polar codes in accordance with aspects of the present disclosure.
  • FIG. 9 shows a diagram of a system including a user equipment (UE) that supports dynamic list size reduction for decoding polar codes in accordance with aspects of the present disclosure.
  • UE user equipment
  • FIG. 10 shows a diagram of a system including a base station that supports dynamic list size reduction for decoding polar codes in accordance with aspects of the present disclosure.
  • FIGs. 11 through 14 show flowcharts illustrating methods that support dynamic list size reduction for decoding polar codes in accordance with aspects of the present disclosure.
  • Some wireless communications systems may support encoding of transmissions using error-correcting codes, such as polar codes.
  • a base station may polar encode a physical downlink control channel (PDCCH) transmission and may transmit the polar encoded transmission to one or more user equipment (UEs) .
  • the PDCCH transmission may contain encoded downlink control information (DCI) bits indicating control information for a UE.
  • DCI downlink control information
  • the UE may monitor a downlink control channel for downlink transmissions from the base station.
  • the UE may perform decoding processes (e.g., successive cancellation (SC) decoding processes) using a polar code. If the UE successfully receives and decodes a codeword for a PDCCH transmission, the UE may determine the encoded DCI bits and the corresponding control information.
  • decoding processes e.g., successive cancellation (SC) decoding processes
  • the UE may implement dynamic list size reduction for decoding transmissions using a polar code.
  • the UE may determine whether to perform the list size reduction based on a threshold value (e.g., a DCI size threshold or a performance loss threshold) , a lookup table, a comparison of path metrics, or some combination of these parameters.
  • the UE may use a list decoder (e.g., a successive cancellation list (SCL) decoder) for decoding a polar encoded codeword.
  • a list decoder may simultaneously track a number of decoding paths for the bits of a codeword when attempting to decode a decoding candidate.
  • the codeword may include distributed error detection check (EDC) bits for early termination, such as cyclic redundancy check (CRC) bits.
  • EDC distributed error detection check
  • CRC cyclic redundancy check
  • the list decoder may check each decoding path to determine if the path passes the EDC based on the decoded values of the EDC bit (s) . If all decoding paths fail the EDC, the list decoder may terminate the decoding process early to reduce complexity and save on processing resources (e.g., the decoder may identify at this stage that the received decoding candidate is not likely to be successfully decoded based on the failed EDCs) .
  • the decoder may prune the decoding paths that fail the EDC and may correspondingly reduce the decoding list size based on this path pruning.
  • Wireless communications systems implementing dynamic list size reduction may reduce the decoding complexity for a codeword with a larger DCI size (e.g., DCI larger than some threshold value, such as 60 bits) .
  • a device may substantially reduce the decoding complexity for a codeword with a large number of information bits. That is, using this technique, a decoder may maintain a large number of decoding paths early in a decoding process and may reduce the number of maintained decoding paths-and, correspondingly, the complexity-later in the decoding process when the bits to decode are generally more reliable.
  • this decoding scheme may be especially effective for long codewords or codewords with a large number of information bits to decode.
  • a UE using dynamic list size reduction for decoding PDCCH transmissions may reduce the decoding complexity by approximately 25%as compared to UEs using early termination without list size reduction.
  • aspects of the disclosure are initially described in the context of wireless communications systems. Additional aspects of the disclosure are illustrated with respect to a device supporting polar encoding/decoding, an example dynamic list size reduction procedure, and a process flow. Aspects of the disclosure are further illustrated by and described with reference to apparatus diagrams, system diagrams, and flowcharts that relate to dynamic list size reduction for decoding polar codes.
  • FIG. 1 illustrates an example of a wireless communications system 100 that supports dynamic list size reduction for decoding polar codes in accordance with aspects of the present disclosure.
  • the wireless communications system 100 includes base stations 105, UEs 115, and a core network 130.
  • the wireless communications system 100 may be a Long Term Evolution (LTE) network, an LTE-Advanced (LTE-A) network, an LTE-A Pro network, or a New Radio (NR) network.
  • LTE Long Term Evolution
  • LTE-A LTE-Advanced
  • LTE-A Pro LTE-Advanced Pro
  • NR New Radio
  • wireless communications system 100 may support enhanced broadband communications, ultra-reliable (e.g., mission critical) communications, low latency communications, or communications with low-cost and low-complexity devices.
  • ultra-reliable e.g., mission critical
  • Base stations 105 may wirelessly communicate with UEs 115 via one or more base station antennas.
  • Base stations 105 described herein may include or may be referred to by those skilled in the art as a base transceiver station, a radio base station, an access point, a radio transceiver, a NodeB, an eNodeB (eNB) , a next-generation Node B or giga-nodeB (either of which may be referred to as a gNB) , a Home NodeB, a Home eNodeB, or some other suitable terminology.
  • Wireless communications system 100 may include base stations 105 of different types (e.g., macro or small cell base stations) .
  • the UEs 115 described herein may be able to communicate with various types of base stations 105 and network equipment including macro eNBs, small cell eNBs, gNBs, relay base stations, and the like.
  • Each base station 105 may be associated with a particular geographic coverage area 110 in which communications with various UEs 115 is supported. Each base station 105 may provide communication coverage for a respective geographic coverage area 110 via communication links 125, and communication links 125 between a base station 105 and a UE 115 may utilize one or more carriers. Communication links 125 shown in wireless communications system 100 may include uplink transmissions from a UE 115 to a base station 105, or downlink transmissions from a base station 105 to a UE 115. Downlink transmissions may also be called forward link transmissions while uplink transmissions may also be called reverse link transmissions.
  • the geographic coverage area 110 for a base station 105 may be divided into sectors making up only a portion of the geographic coverage area 110, and each sector may be associated with a cell.
  • each base station 105 may provide communication coverage for a macro cell, a small cell, a hot spot, or other types of cells, or various combinations thereof.
  • a base station 105 may be movable and therefore provide communication coverage for a moving geographic coverage area 110.
  • different geographic coverage areas 110 associated with different technologies may overlap, and overlapping geographic coverage areas 110 associated with different technologies may be supported by the same base station 105 or by different base stations 105.
  • the wireless communications system 100 may include, for example, a heterogeneous LTE/LTE-A/LTE-A Pro or NR network in which different types of base stations 105 provide coverage for various geographic coverage areas 110.
  • the term “cell” refers to a logical communication entity used for communication with a base station 105 (e.g., over a carrier) , and may be associated with an identifier for distinguishing neighboring cells (e.g., a physical cell identifier (PCID) , a virtual cell identifier (VCID) ) operating via the same or a different carrier.
  • a carrier may support multiple cells, and different cells may be configured according to different protocol types (e.g., machine-type communication (MTC) , narrowband Internet-of-Things (NB-IoT) , enhanced mobile broadband (eMBB) , or others) that may provide access for different types of devices.
  • MTC machine-type communication
  • NB-IoT narrowband Internet-of-Things
  • eMBB enhanced mobile broadband
  • the term “cell” may refer to a portion of a geographic coverage area 110 (e.g., a sector) over which the logical entity operates.
  • UEs 115 may be dispersed throughout the wireless communications system 100, and each UE 115 may be stationary or mobile.
  • a UE 115 may also be referred to as a mobile device, a wireless device, a remote device, a handheld device, or a subscriber device, or some other suitable terminology, where the “device” may also be referred to as a unit, a station, a terminal, or a client.
  • a UE 115 may also be a personal electronic device such as a cellular phone, a personal digital assistant (PDA) , a tablet computer, a laptop computer, or a personal computer.
  • PDA personal digital assistant
  • a UE 115 may also refer to a wireless local loop (WLL) station, an Internet of Things (IoT) device, an Internet of Everything (IoE) device, or an MTC device, or the like, which may be implemented in various articles such as appliances, vehicles, meters, or the like.
  • WLL wireless local loop
  • IoT Internet of Things
  • IoE Internet of Everything
  • MTC massive machine type communications
  • Some UEs 115 may be low cost or low complexity devices, and may provide for automated communication between machines (e.g., via Machine-to-Machine (M2M) communication) .
  • M2M communication or MTC may refer to data communication technologies that allow devices to communicate with one another or a base station 105 without human intervention.
  • M2M communication or MTC may include communications from devices that integrate sensors or meters to measure or capture information and relay that information to a central server or application program that can make use of the information or present the information to humans interacting with the program or application.
  • Some UEs 115 may be designed to collect information or enable automated behavior of machines. Examples of applications for MTC devices include smart metering, inventory monitoring, water level monitoring, equipment monitoring, healthcare monitoring, wildlife monitoring, weather and geological event monitoring, fleet management and tracking, remote security sensing, physical access control, and transaction-based business charging.
  • Some UEs 115 may be configured to employ operating modes that reduce power consumption, such as half-duplex communications (e.g., a mode that supports one-way communication via transmission or reception, but not transmission and reception simultaneously) . In some examples half-duplex communications may be performed at a reduced peak rate. Other power conservation techniques for UEs 115 include entering a power saving “deep sleep” mode when not engaging in active communications, or operating over a limited bandwidth (e.g., according to narrowband communications) . In some cases, UEs 115 may be designed to support critical functions (e.g., mission critical functions) , and a wireless communications system 100 may be configured to provide ultra-reliable communications for these functions.
  • critical functions e.g., mission critical functions
  • a UE 115 may also be able to communicate directly with other UEs 115 (e.g., using a peer-to-peer (P2P) or device-to-device (D2D) protocol) .
  • P2P peer-to-peer
  • D2D device-to-device
  • One or more of a group of UEs 115 utilizing D2D communications may be within the geographic coverage area 110 of a base station 105.
  • Other UEs 115 in such a group may be outside the geographic coverage area 110 of a base station 105, or be otherwise unable to receive transmissions from a base station 105.
  • groups of UEs 115 communicating via D2D communications may utilize a one-to-many (1 ⁇ M) system in which each UE 115 transmits to every other UE 115 in the group.
  • a base station 105 facilitates the scheduling of resources for D2D communications.
  • D2D communications are carried out between UEs 115 without the involvement of a base
  • Base stations 105 may communicate with the core network 130 and with one another.
  • base stations 105 may interface with the core network 130 through backhaul links 132 (e.g., via an S1, N2, N3, or other interface) .
  • Base stations 105 may communicate with one another over backhaul links 134 (e.g., via an X2, Xn, or other interface) either directly (e.g., directly between base stations 105) or indirectly (e.g., via core network 130) .
  • the core network 130 may provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions.
  • the core network 130 may be an evolved packet core (EPC) , which may include at least one mobility management entity (MME) , at least one serving gateway (S-GW) , and at least one Packet Data Network (PDN) gateway (P-GW) .
  • the MME may manage non-access stratum (e.g., control plane) functions such as mobility, authentication, and bearer management for UEs 115 served by base stations 105 associated with the EPC.
  • User IP packets may be transferred through the S-GW, which itself may be connected to the P-GW.
  • the P-GW may provide IP address allocation as well as other functions.
  • the P-GW may be connected to the network operators IP services.
  • the operators IP services may include access to the Internet, Intranet (s) , an IP Multimedia Subsystem (IMS) , or a Packet-Switched (PS) Stream
  • At least some of the network devices may include subcomponents such as an access network entity, which may be an example of an access node controller (ANC) .
  • Each access network entity may communicate with UEs 115 through a number of other access network transmission entities, which may be referred to as a radio head, a smart radio head, or a transmission/reception point (TRP) .
  • TRP transmission/reception point
  • various functions of each access network entity or base station 105 may be distributed across various network devices (e.g., radio heads and access network controllers) or consolidated into a single network device (e.g., a base station 105) .
  • Wireless communications system 100 may operate using one or more frequency bands, typically in the range of 300 MHz to 300 GHz.
  • the region from 300 MHz to 3 GHz is known as the ultra-high frequency (UHF) region or decimeter band, since the wavelengths range from approximately one decimeter to one meter in length.
  • UHF waves may be blocked or redirected by buildings and environmental features. However, the waves may penetrate structures sufficiently for a macro cell to provide service to UEs 115 located indoors. Transmission of UHF waves may be associated with smaller antennas and shorter range (e.g., less than 100 km) compared to transmission using the smaller frequencies and longer waves of the high frequency (HF) or very high frequency (VHF) portion of the spectrum below 300 MHz.
  • HF high frequency
  • VHF very high frequency
  • Wireless communications system 100 may also operate in a super high frequency (SHF) region using frequency bands from 3 GHz to 30 GHz, also known as the centimeter band.
  • SHF region includes bands such as the 5 GHz industrial, scientific, and medical (ISM) bands, which may be used opportunistically by devices that can tolerate interference from other users.
  • ISM bands 5 GHz industrial, scientific, and medical bands
  • Wireless communications system 100 may also operate in an extremely high frequency (EHF) region of the spectrum (e.g., from 30 GHz to 300 GHz) , also known as the millimeter band.
  • EHF extremely high frequency
  • wireless communications system 100 may support millimeter wave (mmW) communications between UEs 115 and base stations 105, and EHF antennas of the respective devices may be even smaller and more closely spaced than UHF antennas. In some cases, this may facilitate use of antenna arrays within a UE 115.
  • mmW millimeter wave
  • the propagation of EHF transmissions may be subject to even greater atmospheric attenuation and shorter range than SHF or UHF transmissions. Techniques disclosed herein may be employed across transmissions that use one or more different frequency regions, and designated use of bands across these frequency regions may differ by country or regulating body.
  • wireless communications system 100 may utilize both licensed and unlicensed radio frequency spectrum bands.
  • wireless communications system 100 may employ License Assisted Access (LAA) , LTE-Unlicensed (LTE-U) radio access technology, or NR technology in an unlicensed band such as the 5 GHz ISM band.
  • LAA License Assisted Access
  • LTE-U LTE-Unlicensed
  • NR NR technology
  • an unlicensed band such as the 5 GHz ISM band.
  • wireless devices such as base stations 105 and UEs 115 may employ listen-before-talk (LBT) procedures to ensure a frequency channel is clear before transmitting data.
  • LBT listen-before-talk
  • operations in unlicensed bands may be based on a CA configuration in conjunction with CCs operating in a licensed band (e.g., LAA) .
  • Operations in unlicensed spectrum may include downlink transmissions, uplink transmissions, peer-to-peer transmissions, or a combination of these.
  • Duplexing in unlicensed spectrum may be based on frequency division duplexing (FDD) , time division duplexing (TDD) , or a combination of both.
  • FDD frequency division duplexing
  • TDD time division duplexing
  • base station 105 or UE 115 may be equipped with multiple antennas, which may be used to employ techniques such as transmit diversity, receive diversity, multiple-input multiple-output (MIMO) communications, or beamforming.
  • wireless communications system 100 may use a transmission scheme between a transmitting device (e.g., a base station 105) and a receiving device (e.g., a UE 115) , where the transmitting device is equipped with multiple antennas and the receiving devices are equipped with one or more antennas.
  • MIMO communications may employ multipath signal propagation to increase the spectral efficiency by transmitting or receiving multiple signals via different spatial layers, which may be referred to as spatial multiplexing.
  • the multiple signals may, for example, be transmitted by the transmitting device via different antennas or different combinations of antennas. Likewise, the multiple signals may be received by the receiving device via different antennas or different combinations of antennas.
  • Each of the multiple signals may be referred to as a separate spatial stream, and may carry bits associated with the same data stream (e.g., the same codeword) or different data streams.
  • Different spatial layers may be associated with different antenna ports used for channel measurement and reporting.
  • MIMO techniques include single-user MIMO (SU-MIMO) where multiple spatial layers are transmitted to the same receiving device, and multiple-user MIMO (MU-MIMO) where multiple spatial layers are transmitted to multiple devices.
  • SU-MIMO single-user MIMO
  • MU-MIMO multiple-user MIMO
  • Beamforming which may also be referred to as spatial filtering, directional transmission, or directional reception, is a signal processing technique that may be used at a transmitting device or a receiving device (e.g., a base station 105 or a UE 115) to shape or steer an antenna beam (e.g., a transmit beam or receive beam) along a spatial path between the transmitting device and the receiving device.
  • Beamforming may be achieved by combining the signals communicated via antenna elements of an antenna array such that signals propagating at particular orientations with respect to an antenna array experience constructive interference while others experience destructive interference.
  • the adjustment of signals communicated via the antenna elements may include a transmitting device or a receiving device applying certain amplitude and phase offsets to signals carried via each of the antenna elements associated with the device.
  • the adjustments associated with each of the antenna elements may be defined by a beamforming weight set associated with a particular orientation (e.g., with respect to the antenna array of the transmitting device or receiving device, or with respect to some other orientation) .
  • a base station 105 may use multiple antennas or antenna arrays to conduct beamforming operations for directional communications with a UE 115. For instance, some signals (e.g. synchronization signals, reference signals, beam selection signals, or other control signals) may be transmitted by a base station 105 multiple times in different directions, which may include a signal being transmitted according to different beamforming weight sets associated with different directions of transmission. Transmissions in different beam directions may be used to identify (e.g., by the base station 105 or a receiving device, such as a UE 115) a beam direction for subsequent transmission and/or reception by the base station 105.
  • some signals e.g. synchronization signals, reference signals, beam selection signals, or other control signals
  • Transmissions in different beam directions may be used to identify (e.g., by the base station 105 or a receiving device, such as a UE 115) a beam direction for subsequent transmission and/or reception by the base station 105.
  • Some signals may be transmitted by a base station 105 in a single beam direction (e.g., a direction associated with the receiving device, such as a UE 115) .
  • the beam direction associated with transmissions along a single beam direction may be determined based at least in in part on a signal that was transmitted in different beam directions.
  • a UE 115 may receive one or more of the signals transmitted by the base station 105 in different directions, and the UE 115 may report to the base station 105 an indication of the signal it received with a highest signal quality, or an otherwise acceptable signal quality.
  • a UE 115 may employ similar techniques for transmitting signals multiple times in different directions (e.g., for identifying a beam direction for subsequent transmission or reception by the UE 115) , or transmitting a signal in a single direction (e.g., for transmitting data to a receiving device) .
  • a receiving device may try multiple receive beams when receiving various signals from the base station 105, such as synchronization signals, reference signals, beam selection signals, or other control signals.
  • a receiving device may try multiple receive directions by receiving via different antenna subarrays, by processing received signals according to different antenna subarrays, by receiving according to different receive beamforming weight sets applied to signals received at a plurality of antenna elements of an antenna array, or by processing received signals according to different receive beamforming weight sets applied to signals received at a plurality of antenna elements of an antenna array, any of which may be referred to as “listening” according to different receive beams or receive directions.
  • a receiving device may use a single receive beam to receive along a single beam direction (e.g., when receiving a data signal) .
  • the single receive beam may be aligned in a beam direction determined based at least in part on listening according to different receive beam directions (e.g., a beam direction determined to have a highest signal strength, highest signal-to-noise ratio, or otherwise acceptable signal quality based at least in part on listening according to multiple beam directions) .
  • the antennas of a base station 105 or UE 115 may be located within one or more antenna arrays, which may support MIMO operations, or transmit or receive beamforming.
  • one or more base station antennas or antenna arrays may be co-located at an antenna assembly, such as an antenna tower.
  • antennas or antenna arrays associated with a base station 105 may be located in diverse geographic locations.
  • a base station 105 may have an antenna array with a number of rows and columns of antenna ports that the base station 105 may use to support beamforming of communications with a UE 115.
  • a UE 115 may have one or more antenna arrays that may support various MIMO or beamforming operations.
  • wireless communications system 100 may be a packet-based network that operate according to a layered protocol stack.
  • PDCP Packet Data Convergence Protocol
  • a Radio Link Control (RLC) layer may in some cases perform packet segmentation and reassembly to communicate over logical channels.
  • RLC Radio Link Control
  • a Medium Access Control (MAC) layer may perform priority handling and multiplexing of logical channels into transport channels.
  • the MAC layer may also use hybrid automatic repeat request (HARQ) to provide retransmission at the MAC layer to improve link efficiency.
  • HARQ hybrid automatic repeat request
  • the Radio Resource Control (RRC) protocol layer may provide establishment, configuration, and maintenance of an RRC connection between a UE 115 and a base station 105 or core network 130 supporting radio bearers for user plane data.
  • RRC Radio Resource Control
  • PHY Physical
  • UEs 115 and base stations 105 may support retransmissions of data to increase the likelihood that data is received successfully.
  • HARQ feedback is one technique of increasing the likelihood that data is received correctly over a communication link 125.
  • HARQ may include a combination of error detection (e.g., using a cyclic redundancy check (CRC) ) , forward error correction (FEC) , and retransmission (e.g., automatic repeat request (ARQ) ) .
  • FEC forward error correction
  • ARQ automatic repeat request
  • HARQ may improve throughput at the MAC layer in poor radio conditions (e.g., signal-to-noise conditions) .
  • a wireless device may support same-slot HARQ feedback, where the device may provide HARQ feedback in a specific slot for data received in a previous symbol in the slot. In other cases, the device may provide HARQ feedback in a subsequent slot, or according to some other time interval.
  • the radio frames may be identified by a system frame number (SFN) ranging from 0 to 1023.
  • SFN system frame number
  • Each frame may include 10 subframes numbered from 0 to 9, and each subframe may have a duration of 1 ms.
  • a subframe may be further divided into 2 slots each having a duration of 0.5 ms, and each slot may contain 6 or 7 modulation symbol periods (e.g., depending on the length of the cyclic prefix prepended to each symbol period) . Excluding the cyclic prefix, each symbol period may contain 2048 sampling periods.
  • a subframe may be the smallest scheduling unit of the wireless communications system 100, and may be referred to as a transmission time interval (TTI) .
  • TTI transmission time interval
  • a smallest scheduling unit of the wireless communications system 100 may be shorter than a subframe or may be dynamically selected (e.g., in bursts of shortened TTIs (sTTIs) or in selected component carriers using sTTIs) .
  • a slot may further be divided into multiple mini-slots containing one or more symbols.
  • a symbol of a mini-slot or a mini-slot may be the smallest unit of scheduling.
  • Each symbol may vary in duration depending on the subcarrier spacing or frequency band of operation, for example.
  • some wireless communications systems may implement slot aggregation in which multiple slots or mini-slots are aggregated together and used for communication between a UE 115 and a base station 105.
  • carrier refers to a set of radio frequency spectrum resources having a defined physical layer structure for supporting communications over a communication link 125.
  • a carrier of a communication link 125 may include a portion of a radio frequency spectrum band that is operated according to physical layer channels for a given radio access technology.
  • Each physical layer channel may carry user data, control information, or other signaling.
  • a carrier may be associated with a pre-defined frequency channel (e.g., an E-UTRA absolute radio frequency channel number (EARFCN) ) , and may be positioned according to a channel raster for discovery by UEs 115.
  • E-UTRA absolute radio frequency channel number E-UTRA absolute radio frequency channel number
  • Carriers may be downlink or uplink (e.g., in an FDD mode) , or be configured to carry downlink and uplink communications (e.g., in a TDD mode) .
  • signal waveforms transmitted over a carrier may be made up of multiple sub-carriers (e.g., using multi-carrier modulation (MCM) techniques such as OFDM or DFT-s-OFDM) .
  • MCM multi-carrier modulation
  • the organizational structure of the carriers may be different for different radio access technologies (e.g., LTE, LTE-A, LTE-A Pro, NR, etc. ) .
  • communications over a carrier may be organized according to TTIs or slots, each of which may include user data as well as control information or signaling to support decoding the user data.
  • a carrier may also include dedicated acquisition signaling (e.g., synchronization signals or system information, etc. ) and control signaling that coordinates operation for the carrier.
  • acquisition signaling e.g., synchronization signals or system information, etc.
  • control signaling that coordinates operation for the carrier.
  • a carrier may also have acquisition signaling or control signaling that coordinates operations for other carriers.
  • Physical channels may be multiplexed on a carrier according to various techniques.
  • a physical control channel and a physical data channel may be multiplexed on a downlink carrier, for example, using time division multiplexing (TDM) techniques, frequency division multiplexing (FDM) techniques, or hybrid TDM-FDM techniques.
  • control information transmitted in a physical control channel may be distributed between different control regions in a cascaded manner (e.g., between a common control region or common search space and one or more UE-specific control regions or UE-specific search spaces) .
  • a carrier may be associated with a particular bandwidth of the radio frequency spectrum, and in some examples the carrier bandwidth may be referred to as a “system bandwidth” of the carrier or the wireless communications system 100.
  • the carrier bandwidth may be one of a number of predetermined bandwidths for carriers of a particular radio access technology (e.g., 1.4, 3, 5, 10, 15, 20, 40, or 80 MHz) .
  • each served UE 115 may be configured for operating over portions or all of the carrier bandwidth.
  • some UEs 115 may be configured for operation using a narrowband protocol type that is associated with a predefined portion or range (e.g., set of subcarriers or RBs) within a carrier (e.g., “in-band” deployment of a narrowband protocol type) .
  • a narrowband protocol type that is associated with a predefined portion or range (e.g., set of subcarriers or RBs) within a carrier (e.g., “in-band” deployment of a narrowband protocol type) .
  • a resource element may consist of one symbol period (e.g., a duration of one modulation symbol) and one subcarrier, where the symbol period and subcarrier spacing are inversely related.
  • the number of bits carried by each resource element may depend on the modulation scheme (e.g., the order of the modulation scheme) .
  • the more resource elements that a UE 115 receives and the higher the order of the modulation scheme the higher the data rate may be for the UE 115.
  • a wireless communications resource may refer to a combination of a radio frequency spectrum resource, a time resource, and a spatial resource (e.g., spatial layers) , and the use of multiple spatial layers may further increase the data rate for communications with a UE 115.
  • a spatial resource e.g., spatial layers
  • Devices of the wireless communications system 100 may have a hardware configuration that supports communications over a particular carrier bandwidth, or may be configurable to support communications over one of a set of carrier bandwidths.
  • the wireless communications system 100 may include base stations 105 and/or UEs 115 that can support simultaneous communications via carriers associated with more than one different carrier bandwidth.
  • Wireless communications system 100 may support communication with a UE 115 on multiple cells or carriers, a feature which may be referred to as carrier aggregation (CA) or multi-carrier operation.
  • a UE 115 may be configured with multiple downlink CCs and one or more uplink CCs according to a carrier aggregation configuration.
  • Carrier aggregation may be used with both FDD and TDD component carriers.
  • wireless communications system 100 may utilize enhanced component carriers (eCCs) .
  • eCC may be characterized by one or more features including wider carrier or frequency channel bandwidth, shorter symbol duration, shorter TTI duration, or modified control channel configuration.
  • an eCC may be associated with a carrier aggregation configuration or a dual connectivity configuration (e.g., when multiple serving cells have a suboptimal or non-ideal backhaul link) .
  • An eCC may also be configured for use in unlicensed spectrum or shared spectrum (e.g., where more than one operator is allowed to use the spectrum) .
  • An eCC characterized by wide carrier bandwidth may include one or more segments that may be utilized by UEs 115 that are not capable of monitoring the whole carrier bandwidth or are otherwise configured to use a limited carrier bandwidth (e.g., to conserve power) .
  • an eCC may utilize a different symbol duration than other CCs, which may include use of a reduced symbol duration as compared with symbol durations of the other CCs.
  • a shorter symbol duration may be associated with increased spacing between adjacent subcarriers.
  • a device such as a UE 115 or base station 105, utilizing eCCs may transmit wideband signals (e.g., according to frequency channel or carrier bandwidths of 20, 40, 60, 80 MHz, etc. ) at reduced symbol durations (e.g., 16.67 microseconds) .
  • a TTI in eCC may consist of one or multiple symbol periods. In some cases, the TTI duration (that is, the number of symbol periods in a TTI) may be variable.
  • Wireless communications systems such as an NR system may utilize any combination of licensed, shared, and unlicensed spectrum bands, among others.
  • the flexibility of eCC symbol duration and subcarrier spacing may allow for the use of eCC across multiple spectrums.
  • NR shared spectrum may increase spectrum utilization and spectral efficiency, specifically through dynamic vertical (e.g., across the frequency domain) and horizontal (e.g., across the time domain) sharing of resources.
  • Some wireless communications systems 100 may support encoding of transmissions between base stations 105 and UEs 115 using polar codes.
  • a base station 105 may polar encode a PDCCH transmission and may transmit the polar encoded transmission via a downlink channel (e.g., downlink control channel) to one or more UEs 115.
  • the PDCCH transmission may contain encoded DCI bits (e.g., polar encoded DCI bits) indicating control information for a UE 115.
  • the UE 115 may monitor the downlink control channel for downlink transmissions from the base station 105.
  • the UE 115 may perform a decoding process (e.g., SC decoding) using the polar code. If the UE 115 successfully receives and decodes a codeword for a PDCCH transmission, the UE 115 may determine the encoded DCI bits and the corresponding control information.
  • a decoding process e.g., SC decoding
  • the UE 115 may implement dynamic list size reduction for decoding transmissions using a polar code. In some cases, the UE 115 may determine whether to perform the list size reduction based on a performance loss value, a decoding complexity reduction value, or some tradeoff between these two values.
  • the UE 115 may use a list decoder (e.g., an SCL decoder) for decoding a polar encoded codeword.
  • a list decoder may simultaneously track a number of decoding paths for the bits of a codeword when attempting to decode a decoding candidate.
  • the codeword may include distributed EDC bits for early termination, such as CRC bits.
  • the list decoder may check each decoding path to determine if the path passes the EDC based on the decoded values of the EDC bit (s) . If all decoding paths fail the EDC, the list decoder may terminate the decoding process early to reduce complexity and save on processing resources (e.g., the decoder may identify at this stage that the received decoding candidate is not likely to be successfully decoded based on the failed EDCs) .
  • the decoder may prune the decoding paths that fail the EDC and may correspondingly reduce the decoding list size based on this path pruning.
  • FIG. 2 illustrates an example of a wireless communications system 200 that supports dynamic list size reduction for decoding polar codes in accordance with aspects of the present disclosure.
  • the wireless communications system 200 may be an example of a wireless communications system 100 as described with reference to FIG. 1.
  • the wireless communications system 200 may include base station 105-a and UE 115-a, which may be examples of the corresponding devices described with reference to FIG. 1.
  • Base station 105-a may provide network coverage for geographic area 110-a and may communicate with UE 115-a. For example, base station 105-a may transmit control information and data to UE 115-a on a downlink channel 205.
  • base station 105-a may encode a PDCCH transmission 210 using an error-correcting code, such as a polar code, and may transmit the PDCCH transmission 210 on the downlink channel 205 to UE 115-a.
  • UE 115-a may detect the PDCCH transmission 210 and may attempt to decode the information contained in the PDCCH transmission 210 using the error-correcting code (e.g., the polar code) .
  • the error-correcting code e.g., the polar code
  • base stations 105 and UEs 115 may handle PDCCH transmissions 210 encoded using polar codes.
  • base station 105-a may determine a set of information bits for transmission, where the information bits indicate DCI.
  • Base station 105-a may polar encode the set of information bits to obtain a set of coded bits.
  • base station 105-a may additionally include a set of EDC bits (e.g., CRC bits, parity bits) in the transmission.
  • base station 105-a may include a number (e.g., 8, 16, 24, 32) of EDC bits in the transmission.
  • the EDC bits 220 may be distributed throughout the codeword 215 to support early termination of a decoding process at UE 115-a.
  • Base station 105-a may transmit the codeword 215 for the PDCCH transmission 210 to UE 115-a.
  • UE 115-a may monitor the downlink channel 205 for transmissions from base station 105-a.
  • UE 115-a may perform blind decoding on a number of decoding candidates using a polar code to attempt to detect the codeword 215.
  • UE 115-a may use a list decoder (e.g., SCL decoder) to attempt to decode each received decoding candidate. Using the list decoder, UE 115-a may determine multiple decoding paths for a first subset of bits of a decoding candidate.
  • the number of decoding paths used for the first subset of bits may be based on a decoder capability of the list decoder.
  • the decoder may check each of the decoding paths using the EDC bits 220. For example, based on an EDC operation and the bit decisions for a decoding path, the decoder may expect a certain value or set of values for the EDC bits 220. If the first set of EDC bits 220 matches the expected set of EDC bits for a given decoding path, the decoding path passes the EDC. If the first set of EDC bits 220 does not match the expected set of EDC bits for a given decoding path, the decoding path fails the EDC.
  • the decoder may immediately terminate the decoding process (e.g., without decoding any bits in the codeword 215 sequentially after the first set of EDC bits 220) .
  • UE 115-a may accordingly obtain an early termination gain based on the distributed EDC bits 220.
  • the decoder may continue the decoding process if any decoding path passes the EDC at the first set of EDC bits 220.
  • the decoder may reduce the complexity of the decoding process by reducing the effective list size following the EDC procedure. For example, the decoder may prune each decoding path that fails the EDC and may additionally reduce its effective list size down to the number of remaining decoding paths that pass the EDC. Following the dynamic list size reduction, the decoder may continue the decoding process for a second subset of bits following the first set of EDC bits 220.
  • the decoder may determine bit decisions for a number of decoding paths equal to this reduced list size, where each decoding path contains a bit decision (e.g., either a 1 bit value or a 0 bit value) for each bit of the first subset of bits and the second subset of bits in the codeword 215.
  • the decoder may identify additional sets of EDC bits 220. At these additional sets of EDC bits 220, the decoder may again check each decoding path, and may perform further list size reduction based on any decoding paths that fail the additional EDC procedures. If every remaining decoding path fails any EDC, the decoder may terminate the decoding process at that EDC.
  • the decoder may determine that this decoding path contains the successfully decoded set of bits.
  • UE 115-a may determine the DCI and corresponding control information based on this successfully decoded set of bits.
  • Some systems may implement an early termination scheme using distributed EDC bits 220 without dynamic list size reduction.
  • a device in the system decoding a candidate codeword may determine if any decoding path passes the EDC operation. If no path passes, the device will terminate the decoding process early. If any decoding path passes the EDC operation, the device will continue the decoding process (i.e., using the same list size) .
  • the device may or may not prune the decoding paths that fail the EDC operation, but if the device prunes decoding paths, the device will make bit decisions for the surviving decoding paths such that the decoding process returns to the initial list size.
  • the decoder may prune the two paths that fail the EDC, but at the next level of the decoding process the decoder will select both a 0 bit and a 1 bit for each of the surviving decoding paths. In this way, these two surviving decoding paths split back into four total decoding paths to return to the initial decoding list size.
  • Systems operating using an early termination scheme may achieve a complexity reduction gain for the decoding process based on the termination rate of decoding.
  • these decoders may achieve larger gains in decoding complexity reduction for smaller DCI sizes.
  • Codewords with smaller DCI sizes may already have lower decoding complexities than codewords with larger DCI sizes.
  • These early termination schemes may be ineffective or less effective for reducing the decoding complexity of codewords with larger DCI sizes and-correspondingly-more inherent decoding complexity (e.g., for a range of codeword sizes and numbers of EDC bits) .
  • a wireless communications system 200 implementing dynamic list size reduction may reduce the decoding complexity for a codeword with a larger DCI size (e.g., DCI larger than some threshold value, such as 60 bits) .
  • DCI size e.g., DCI larger than some threshold value, such as 60 bits
  • a device may greatly reduce the decoding complexity for a codeword with a large number of information bits. That is, using this technique, a decoder may maintain a large number of decoding paths early in a decoding process and may reduce the number of maintained decoding paths-and, correspondingly, the complexity-later in the decoding process when the bits to decode are generally more reliable. As such, this decoding scheme may be especially effective for long codewords or codewords with a large number of information bits to decode.
  • the list size reduction scheme may achieve additional gains in decoding complexity reduction. For example, list size reduction may achieve approximately a 25%improvement in complexity reduction as compared to early termination without list size reduction. This additional decoding complexity reduction may be achieved across a number of possible codeword sizes (e.g., 108 bits, 216 bits, 432 bits, or 864 bits for PDCCH block lengths) .
  • the complexity reduction gain for list size reduction as compared to early termination without list size reduction may be defined by the following equation:
  • T is the total number of information bits that would be decoded for the full list size by a decoder implementing early termination without list size reduction
  • p is the total number of information bits that would be decoded by a decoder implementing list size reduction (e.g., in addition to early termination) .
  • the list size reduction scheme may experience performance loss (e.g., block error rate (BLER) performance loss) .
  • BLER block error rate
  • this performance loss may be mitigated or insignificant for codewords with large sets of information bits (e.g., for codewords of varying sizes) .
  • a decoder operating using list size reduction for a codeword with a large number of information bits may experience a performance loss of approximately 0.1 decibel (dB) as compared to a decoder operating using early termination.
  • dB decibel
  • this small reduction in performance may result in a large reduction in decoding complexity (e.g., approximately 25%) .
  • implementing list size reduction at a decoder may efficiently reduce decoding complexity for polar codes, especially for PDCCH transmission with larger DCI sizes.
  • FIG. 3 illustrates an example of a device 300 that supports dynamic list size reduction for decoding polar codes in accordance with aspects of the present disclosure.
  • device 300 may be implemented by aspects of a wireless communications system 100 or 200.
  • the device 300 may be any device within a wireless communications system that performs an encoding or decoding process (e.g., using an error-correcting code, such as a polar code) .
  • device 300 may be an example of a UE 115 or a base station 105 as described with reference to FIGs. 1 and 2.
  • a base station 105 transmitting a polar encoded PDCCH transmission may be an example of a device 300 including at least a memory 305, an encoder 310, and a transmitter 315.
  • a UE 115 receiving the polar encoded PDCCH transmission may be an example of a device 300 including at least a receiver 315, a decoder 310, and a memory 305.
  • device 300 may include a memory 305, an encoder/decoder 310, and a transmitter/receiver 315.
  • First bus 320 may connect memory 305 to encoder/decoder 310 and second bus 325 may connect encoder/decoder 310 to transmitter/receiver 315.
  • device 300 may have data stored in memory 305 to be transmitted to another device, such as a UE 115 or base station 105.
  • device 300 may retrieve from memory 305 the data for transmission.
  • the data for transmission may include downlink control data for a UE 115 or a set of UEs 115.
  • the data may include a number of payload bits, ‘A, ’ which may be 1s or 0s, provided from memory 305 to encoder/decoder 310 via first bus 320.
  • these payload bits may be combined with a number of error checking bits (e.g., EDC bits, such as CRC bits or parity check bits) , ‘C, ’ to form a total set of information bits, ‘A+C. ’
  • EDC bits may be distributed throughout the information bits.
  • this number of information bits, K, or the number of payload bits, A may be based on the selected DCI format.
  • the encoder/decoder 310 may implement a polar code with a block length, ‘N, ’ for encoding the information bits, where N may be different than or the same as K. Such a polar code may be referred to as an (N, K) polar code.
  • the bits not allocated as information bits e.g., N-K bits
  • Frozen bits may be bits with a default value known to both the encoding and decoding devices 300 (e.g., bits with a default bit value of 0) .
  • the transmitter 315 may transmit these N encoded bits in a PDCCH transmission to a receiving device 300, and the receiving device 300 may receive the transmission at a receiver 315 and may pass the received information along to a decoder 310 for polar decoding.
  • decoder 310 may be an example of an SC or SCL decoder.
  • a UE 115 or base station 105 may receive a transmission including a codeword at receiver 315 and may send the transmission to the SCL decoder (e.g., decoder 310) .
  • the SCL decoder may determine input logarithmic-likelihood ratios (LLRs) for the bit channels of the received codeword.
  • LLRs logarithmic-likelihood ratios
  • the SCL decoder may determine decoded LLRs based on these input LLRs, where the decoded LLRs correspond to each bit channel of the polar code. These decoded LLRs may be referred to as bit metrics.
  • the SCL decoder may determine the corresponding bit is a 0 bit, and a negative LLR may correspond to a 1 bit.
  • the SCL decoder may use the bit metrics to determine the decoded bit values.
  • the SCL decoder may employ multiple concurrent SC decoding processes. Each SC decoding process may decode the codeword sequentially (e.g., in order of the bit channel indices, in the U-domain) . Due to the combination of multiple SC decoding processes, the SCL decoder may calculate multiple decoding path candidates. For example, an SCL decoder of list size ‘L’ (i.e., the SCL decoder has L SC decoding processes) may calculate L decoding path candidates, and a corresponding reliability metric (e.g., a path metric) for each decoding path candidate.
  • the path metric may represent a reliability of a decoding path candidate or a probability that the corresponding decoding path candidate is the correct set of decoded bits.
  • the path metric may be based on the determined bit metrics and the bit values selected at each bit channel.
  • the SCL decoder may have a number of levels equal to the number of bit channels in the received codeword. At each level, each decoding path candidate may be extended by both a 0 bit and a 1 bit. The SCL decoder may then select L decoding paths to survive based on the path metrics of the 2L extended decoded paths (e.g., the SCL decoder may select the L paths with the best path metrics) and may prune the unselected decoding paths to maintain the proper list size for decoding.
  • the SCL decoder may select a decoding path candidate based on the path metrics and may output the bits corresponding to the selected decoding path as the decoded sets of bits. For example, the SCL decoder may select the decoding paths with the best path metrics for error checking, and the decoder 310 may determine a successfully decoded path candidate based on a result of the error checking process.
  • the decoder 310 may support dynamic list size reduction based on distributed error checking throughout a codeword.
  • a received PDCCH transmission may include sets of EDC bits distributed throughout the codeword.
  • the decoder 310 may perform an error checking procedure for all surviving decoding path candidates upon decoding each EDC bit or each set of EDC bits. If the error check fails for all of the decoding path candidates, the decoder 310 may terminate the decoding process. This may involve the decoder 310 performing early termination if all of the decoding paths fail an error check prior to the decoder 310 determining bit values for the entire codeword.
  • the decoder 310 may terminate the decoding process (i.e., determine that the decoding process was unsuccessful) based on no decoding path candidates passing a final error checking procedure after determining bit values for each bit in the codeword.
  • the receiving device 300 may transmit a negative acknowledgment (NACK) message based on an unsuccessful decoding process (e.g., whether the decoding process is terminated early or not) .
  • NACK negative acknowledgment
  • a subset-rather than the entire set-of the decoding path candidates may fail an error check for one or more distributed EDC bits (e.g., CRC bits) .
  • the decoder 310 may maintain L concurrent SC decoding processes corresponding to L different decoding paths.
  • the decoder 310 may identify L′decoding path candidates that fail the error checking procedure, where L′ ⁇ L. The decoder 310 may continue the decoding process because L-L′decoding paths pass the error check, but the decoder 310 may perform list size reduction to reduce the complexity of the decoding process.
  • the decoder 310 may prune (i.e., stop the decoding processes for) the L′decoding paths that fail the error check. Additionally, the decoder 310 may reduce the list size from L to L-L′. In these cases, following the first set of distributed EDC bits, the SCL decoder performs L-L′ concurrent SC decoding processes to track L-L′decoding paths. Reducing the effective list size for the decoder 310 may not increase the false alarm rate (FAR) for the decoding process, as it does not increase the likelihood that incorrect decoding paths will pass every error check in the decoding process.
  • FAR false alarm rate
  • the decoder 310 may perform multiple error checks during the decoding process (e.g., based on the distribution of the EDC bits) . At each error checking procedure, the decoder 310 may determine whether to reduce the effective list size of the decoding process, terminate the decoding process, or continue the decoding process unchanged. For example, the decoder 310 may identify a second set of distributed EDC bits following the first set of EDC bits and the list reduction procedure. The decoder 310 may check each of the L-L′decoding paths based on the determined values for the EDC bits and may determine which decoding paths pass the error check and which decoding paths fail the error check. If all of the decoding paths fail the error check, the decoder 310 may terminate the decoding process immediately.
  • the decoder 310 may determine to prune the failed paths and further reduce the effective list size for decoding. For example, if L′′ decoding path candidates fail the error check, where L′′ ⁇ L-L′, the decoder 310 may further reduce the list size from L-L′to L-L′-L′′to further reduce the decoding complexity. In some cases, the decoder 310 may include a minimum list size, L min , for list size reduction. As long as at least one decoding path passes an error check (e.g., a CRC) , the decoder 310 may maintain a list size of at least L min .
  • an error check e.g., a CRC
  • the decoder 310 may reduce the list size to two based on the L min value, rather than reducing the list size all the way down to one.
  • the two paths may then be selected based on path metrics, for example.
  • the receiving device 300 may determine whether to perform dynamic list size reduction during a decoding process based on one or more threshold values (e.g., in order to support optimization of the decoding process) .
  • the device 300 may implement a threshold DCI size for list size reduction.
  • This threshold DCI size may be a positive integer (e.g., 60) , where the decoder 310 may perform path pruning and dynamic list size reduction if the expected DCI size (e.g., in bits) for a decoding candidate is larger than this threshold DCI size.
  • the threshold may vary by polar code size (e.g., different thresholds for different values of N) .
  • the device 300 may implement a performance loss threshold.
  • the device 300 may perform path pruning and list size reduction.
  • the receiving device 300 may use a single decoder 310 that can dynamically switch between decoding using dynamic list size reduction and decoding without dynamic list size reduction.
  • the receiving device 300 may include a first decoder 310 that operates using dynamic list size reduction and a second decoder 310 that operates without dynamic list size reduction, and the device 300 may select between at least these two decoders 310 (e.g., based on the threshold) .
  • a decoder 310 operating without dynamic list size reduction may or may not still perform path pruning (e.g., for decoding path candidates that fail EDCs) .
  • the receiving device 300 may use a lookup table to determine whether to perform dynamic list size reduction during the decoding process. This lookup table may be based on the (N, K) combinations supported by the devices 300 and corresponding estimated performance loss values. If the performance loss for a given (N, K) pair is small (e.g., below some threshold, such as 0.1 dB) , the device 300 may implement list size reduction for received decoding candidates expected to correspond to that (N, K) pair. In some cases, the lookup table may store estimated performance loss values for each supported codeword size and information bit set size combination (e.g., each (N, K) pair) , where the estimated performance losses may be determined based on equations, simulations, historical data, or the like. In other cases, the lookup table may store an indication (e.g., a Boolean value) of whether or not to use dynamic list size reduction for each supported (N, K) pair.
  • an indication e.g., a Boolean value
  • the decoder 310 may dynamically determine whether to reduce the list size at each error checking procedure. For example, the decoder 310 may determine whether to reduce the list size for the remainder of the decoding process based on current LLRs or path metrics for one or more of the decoding path candidates. In a first example, the decoder 310 may determine to perform list size reduction if a “best” decoding path (e.g., the decoding path of the set of decoding paths with the lowest path metric) passes the EDC.
  • a “best” decoding path e.g., the decoding path of the set of decoding paths with the lowest path metric
  • the decoder 310 may determine not to reduce the list size for decoding. In a second example, the decoder 310 may determine to perform dynamic list size reduction based on comparing at least one path metric for a path that passes the EDC with at least one path metric for a path that fails the EDC. For example, the decoder 310 may determine a difference between the minimum or maximum path metric of the decoding paths that pass an error check and the minimum path metric of the decoding paths that fail the error check. If this determined difference is greater than a threshold path metric difference, the decoder 310 may determine to perform list size reduction.
  • a threshold path metric difference the decoder 310 may determine to perform list size reduction.
  • the receiving device 300 may implement any number of the above thresholds to determine whether to perform list size reduction.
  • list size reduction may be more critical for codewords with large DCI sizes (e.g., due to the larger decoding complexity for decoding codewords with large DCI sizes) .
  • Applying one or more of the thresholds described herein may support a tradeoff between the performance loss and complexity reduction achieved by implementing list size reduction. For example, reducing the list size during the decoding procedure may reduce the decoding complexity, but may in some cases result in performance loss.
  • Implementing a threshold to determine whether to perform the list size reduction may allow the device 300 or decoder 310 to optimize polar decoding by avoiding performing list size reduction that may result in significant performance loss or insignificant complexity reduction.
  • FIG. 4 illustrates an example of a dynamic list size reduction procedure 400 for decoding polar codes in accordance with aspects of the present disclosure.
  • the dynamic list size reduction procedure 400 may be performed by a device, such as a device 300, base station 105, or UE 115, as described with reference to FIGs. 1 through 3.
  • a device may identify a decoding candidate for a codeword and may perform a decoding process using a list decoder (e.g., an SCL decoder) and a polar code.
  • the decoding process may include the dynamic list size reduction procedure 400 to reduce the complexity of the decoding process.
  • the dynamic list size reduction procedure 400 may be illustrated as a decoding tree, where each branch of the tree corresponds to the bits for a decoding path 405.
  • This initial list size may be based on a capability of the device (e.g., a maximum list size, L max supported by a decoder of the device) .
  • the decoder may track two decoding paths 405 (e.g., one path with a 1 bit value and one path with a 0 bit value) .
  • this may not be the first bit of the decoding process and may instead be the first information bit of the decoding process (e.g., the decoder may maintain a single decoding path 405 for a set of preceding frozen bits before the first information bit in the codeword) .
  • the decoder may split the two decoding paths 405 into four decoding paths 405 (e.g., corresponding to the decoded bit values 00, 01, 10, and 11) .
  • the decoder may determine the four decoding paths 405 with the “best” (e.g., lowest) path metrics.
  • the decoder For example based on the four decoding paths 405 at the second level, the decoder has eight possible decoding paths 405 at the third level (e.g., corresponding to the decoded bit values 000, 001, 010, 011, 100, 101, 110, and 111) .
  • the decoder may select the decoding paths 405 most likely to be successful based on the calculated path metrics for each of these eight paths, where the path metrics are calculated based on the input LLR values for the received decoding candidate.
  • the decoding paths 405 containing the decoded bit values 000, 001, 100, and 101 may correspond to the most reliable paths (e.g., the paths with the lowest path metrics of the eight possible paths) .
  • the decoder may identify an EDC bit (e.g., a CRC bit) for an EDC process 410-a.
  • the decoder may again determine the four decoding paths 405 (e.g., decoding paths 405-a, 405-b, 405-c, and 405-d) with the best (e.g., lowest) path metrics based on the four surviving decoding paths 405.
  • the decoder may then perform an EDC process 410-a on the decoding paths 405 based on the determined bit values for the EDC bits. For example, based on an EDC calculation, the decoder may expect to decode a certain EDC bit value or set of EDC bits values based on each decoding path 405.
  • the corresponding decoding path 405 may pass the EDC process 410-a. If the decoder determines an EDC bit value or a set of EDC bit values different from the expected EDC bit value (s) , the corresponding decoding path 405 may fail the EDC process 410-a. As illustrated, for the decoding path 101, the decoder may expect an EDC bit value of 1. As such decoding path 405-a may pass the EDC, while decoding path 405-b may fail the EDC. Similarly, the decoder may expect an EDC bit value of 0 for decoding path 100 and an EDC bit value of 0 for decoding path 001. As such, decoding path 405-c may pass the EDC process 410-a and decoding path 405-d may fail the EDC process 410-a.
  • the decoder may perform path pruning and list size reduction processes based on the EDC process 410-a. In some cases, the decoder may automatically perform the list size reduction (e.g., based on a configuration of the decoder) . In other cases, the decoder may determine to perform the list size reduction based on one or more characteristics of the decoding candidate, the decoding paths, or a combination of these. The decoder may prune any decoding paths 405 that fail the EDC process 410-a. For example, the decoder may halt the decoding processes for decoding paths 405-b and 405-d.
  • the decoder may reduce the effective list size for the decoding process.
  • the decoder may determine decoding paths 405 based on this reduced list size and the decoding paths that survived the path pruning procedure (e.g., decoding paths 405-a and 405-c) .
  • the decoder may continue with two decoding paths 405 until reaching a next EDC process 410 (e.g., EDC process 410-b, which may be an example of a CRC operation or a parity check) or until the codeword is completely decoded.
  • EDC process 410-b the decoder may again check each of the surviving decoding paths 405-e and 405-f based on the decoded EDC bit or bits.
  • the decoder may support a single list size reduction process, and may not reduce the list size further at EDC process 410-b. In other cases, the decoder may further reduce the effective list size based on the number of decoding paths 405 that pass this next EDC process 410-b.
  • the decoder may terminate the decoding process early if all of the surviving decoding paths 405 (e.g., both decoding path 405-e and decoding path 405-f) fail the EDC process 410-b. If this EDC process 410-b is a final EDC process 410 for a completely decoded codeword, the decoder may determine that a decoding path 405 that passes this final EDC process 410 is successfully decoded. For example, if decoding path 405-e passes the EDC process 410-b, and if the EDC process 410-b is a final EDC process 410 for the codeword, the decoder may identify bits 101001 as the successfully decoded bits. After removing any frozen bits from this set of bits, the decoder may determine the payload bits received in the transmission. In one specific cases, these payload bits may correspond to DCI received in a PDCCH transmission.
  • FIG. 5 illustrates an example of a process flow 500 that supports dynamic list size reduction for decoding polar codes in accordance with aspects of the present disclosure.
  • the process flow 500 may include a base station 105-b and a UE 115-b, which may be examples of the corresponding devices described with reference to FIGs. 1 and 2. Additionally, base station 105-b and UE 115-b may be examples of devices 300 as described with reference to FIG. 3.
  • Alternative examples of the following may be implemented, where some steps are performed in a different order than described or are not performed at all. In some cases, steps may include additional features not mentioned below, or further steps may be added.
  • base station 105-b may encode a set of information bits using a polar code.
  • This set of information bits may be an example of a set of DCI bits for a PDCCH transmission.
  • the information bits may further include distributed EDC bits, such as CRC bits.
  • base station 105-b may transmit the PDCCH transmission encoded using the polar code to UE 115-b.
  • UE 115-b may monitor for downlink transmissions from base station 105-b and may receive a decoding candidate associated with a codeword for the PDCCH transmission.
  • UE 115-b may perform a decoding process on the received decoding candidate.
  • This decoding process may be an example of a list decoding process (e.g., using an SCL decoder) .
  • UE 115-b may determine path metrics for each of a first set of decoding paths over a first subset of bit channels of the polar code, where the first set of decoding paths corresponds to a first list size.
  • This first list size may be based on a capability (e.g., a maximum supported list size) of the SCL decoder performing the decoding process at UE 115-b.
  • UE 115-b may identify an EDC bit or a set of EDC bits of the set of information bits.
  • UE 115-b may perform an EDC operation on the first set of decoding paths using respective values of the EDC bit or the set of EDC bits.
  • the EDC operation may be an example of a CRC operation.
  • UE 115-b may identify a number of decoding paths of the first set of decoding paths that fail the EDC operation.
  • UE 115-b may determine whether to reduce the list size for the decoding process. For example, UE 115-b may reduce the decoding process from the first list size to a second list size based on a threshold value.
  • this threshold value may be a threshold DCI size.
  • UE 115-b may determine an expected DCI size for the decoding candidate and may compare the expected DCI size to the threshold DCI size. If the expected DCI size for the decoding candidate is larger than the threshold DCI size, UE 115-b may reduce the list size for the decoding process following the EDC operation.
  • this threshold value may be a threshold performance loss value.
  • UE 115-b may store a lookup table in memory containing estimated performance loss values for the decoding process for different combinations of numbers of information bits and codeword lengths. UE 115-b may identify an estimated performance loss value from the lookup table based on an expected number of information bits and expected codeword length for the decoding candidate and may compare the identified estimated performance loss value to the threshold performance loss value. If the identified estimated performance loss value is less than the threshold performance loss value, UE 115-b may reduce the list size for the decoding process following the EDC operation.
  • the threshold value may be preconfigured at UE 115-b.
  • UE 115-b may receive a configuration message (e.g., from base station 105-b) indicating the threshold value.
  • UE 115-b may dynamically determine the threshold value based on any number of variables (e.g., channel conditions, a number of NACKs performed, etc. ) .
  • UE 115-b may store a lookup table in memory containing a list size reduction enablement value for the decoding process for different combinations of numbers of information bits and codeword lengths.
  • this list size reduction enablement value may be a Boolean value either indicating to perform list size reduction when decoding a codeword of the given length and number of information bits or to maintain a same list size when decoding the codeword of the given length and number of information bits.
  • UE 115-b may determine whether to reduce the list size for the decoding process from the first list size to a second list size based on the stored lookup table.
  • UE 115-b may compare one or more path metrics for decoding paths of the first set of decoding paths that fail the EDC operation with one or more path metrics for decoding paths of the first set of decoding paths that pass the EDC operation and may determine to reduce the list size for the decoding process based on the comparison. In some cases, UE 115-b may compare a minimum path metric for the decoding paths that fail the EDC operation with a minimum path metric for the decoding paths that pass the EDC operation. In a first example, UE 115-b may determine to reduce the list size for decoding if the minimum path metric for the paths that pass the EDC operation is less than the minimum path metric for the paths that fail the EDC operation.
  • UE 115-b may determine to reduce the list size for decoding if the difference between the minimum path metric for the decoding paths that fail the EDC operation and the minimum path metric for the decoding paths that pass the EDC operation is greater than a path metric difference threshold.
  • UE 115-b may reduce the effective list size for the decoding process from the first list size to a second list size. Additionally, UE 115-b may prune the decoding paths of the first set of decoding paths that fail the EDC operation 530.
  • UE 115-b may determine path metrics for each of a second set of decoding paths over a second subset of bit channels of the polar code, where the second set of decoding paths are continuations of the paths of the first set of decoding paths that pass the EDC operation.
  • the number of decoding paths for the second set of decoding paths may correspond to the second list size, where the second list is equal to the number of decoding paths that pass the EDC operation (i.e., the first list size minus the number of decoding paths of the first set of decoding paths that fail the EDC operation) .
  • UE 115-b may identify further EDC bits or sets of EDC bits. At each EDC bit or set of EDC bits, UE 115-b may maintain a same list size for decoding, reduce the list size for decoding (e.g., based on the current list size and the number of decoding paths that fail the EDC operation) , or terminate the decoding process (e.g., if all of the decoding paths fail the EDC operation) .
  • This list size reduction scheme may be an example of an efficient complexity reduction scheme for SCL decoding of polar codes. By reducing the effective list size for decoding, UE 115-b may achieve a significant reduction in decoding complexity.
  • FIG. 6 shows a block diagram 600 of a device 605 that supports dynamic list size reduction for decoding polar codes in accordance with aspects of the present disclosure.
  • the device 605 may be an example of aspects of a UE 115 or base station 105 as described herein.
  • the device 605 may include a receiver 610, a dynamic list size decoder 615, and a transmitter 620.
  • the device 605 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses) .
  • Receiver 610 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to dynamic list size reduction for decoding polar codes, etc. ) . Information may be passed on to other components of the device 605.
  • the receiver 610 may be an example of aspects of the transceiver 920 or 1020 as described with reference to FIGs. 9 and 10.
  • the receiver 610 may utilize a single antenna or a set of antennas.
  • the dynamic list size decoder 615 may receive a decoding candidate associated with a codeword, the codeword corresponding to a set of information bits encoded using a polar code and may perform a decoding process on the decoding candidate.
  • the decoding process can include determining path metrics for each of a first set of decoding paths over a first subset of bit channels of the polar code, where the first set of decoding paths corresponds to a first list size, identifying an EDC bit of the set of information bits, performing an EDC operation on the first set of decoding paths using respective values of the EDC bit, and determining path metrics for each of a second set of decoding paths over a second subset of bit channels of the polar code, where the second set of decoding paths corresponds to a second list size, and where the second list size is determined based on the first list size and a number of decoding paths of the first set of decoding paths that fail the EDC operation.
  • the dynamic list size decoder 615 may be an example of aspects of the dynamic list
  • the dynamic list size decoder 615 may be implemented in hardware, code (e.g., software or firmware) executed by a processor, or any combination thereof. If implemented in code executed by a processor, the functions of the dynamic list size decoder 615, or its sub-components may be executed by a general-purpose processor, a digital signal processor (DSP) , an application-specific integrated circuit (ASIC) , a field-programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described in the present disclosure.
  • DSP digital signal processor
  • ASIC application-specific integrated circuit
  • FPGA field-programmable gate array
  • the dynamic list size decoder 615 may be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations by one or more physical components.
  • the dynamic list size decoder 615, or its sub-components may be a separate and distinct component in accordance with various aspects of the present disclosure.
  • the dynamic list size decoder 615, or its sub-components may be combined with one or more other hardware components, including but not limited to an input/output (I/O) component, a transceiver, a network server, another computing device, one or more other components described in the present disclosure, or a combination thereof in accordance with various aspects of the present disclosure.
  • I/O input/output
  • Transmitter 620 may transmit signals generated by other components of the device 605.
  • the transmitter 620 may be collocated with a receiver 610 in a transceiver.
  • the transmitter 620 may be an example of aspects of the transceiver 920 or 1020 as described with reference to FIGs. 9 and 10.
  • the transmitter 620 may utilize a single antenna or a set of antennas.
  • FIG. 7 shows a block diagram 700 of a device 705 that supports dynamic list size reduction for decoding polar codes in accordance with aspects of the present disclosure.
  • the device 705 may be an example of aspects of a device 605, a UE 115, or a base station 105 as described herein.
  • the device 705 may include a receiver 710, a dynamic list size decoder 715, and a transmitter 750.
  • the device 705 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses) .
  • Receiver 710 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to dynamic list size reduction for decoding polar codes, etc. ) . Information may be passed on to other components of the device 705.
  • the receiver 710 may be an example of aspects of the transceiver 920 or 1020 as described with reference to FIGs. 9 and 10.
  • the receiver 710 may utilize a single antenna or a set of antennas.
  • the dynamic list size decoder 715 may be an example of aspects of the dynamic list size decoder 615 as described herein.
  • the dynamic list size decoder 715 may include a decoding candidate reception component 720, a polar decoding component 725, a path metric determination component 730, an EDC bit identifier 735, an EDC operation component 740, and a list size reduction component 745.
  • the dynamic list size decoder 715 may be an example of aspects of the dynamic list size decoder 910 or 1010 as described herein.
  • the decoding candidate reception component 720 may receive a decoding candidate associated with a codeword, the codeword corresponding to a set of information bits encoded using a polar code.
  • the polar decoding component 725 may perform a decoding process on the decoding candidate.
  • the path metric determination component 730 may determine path metrics for each of a first set of decoding paths over a first subset of bit channels of the polar code, where the first set of decoding paths corresponds to a first list size.
  • the EDC bit identifier 735 may identify an EDC bit of the set of information bits.
  • the EDC operation component 740 may perform an EDC operation on the first set of decoding paths using respective values of the EDC bit.
  • the list size reduction component 745 may determine path metrics for each of a second set of decoding paths over a second subset of bit channels of the polar code, where the second set of decoding paths corresponds to a second list size, and where the second list size is determined based on the first list size and a number of decoding paths of the first set of decoding paths that fail the EDC operation.
  • Transmitter 750 may transmit signals generated by other components of the device 705.
  • the transmitter 750 may be collocated with a receiver 710 in a transceiver.
  • the transmitter 750 may be an example of aspects of the transceiver 920 or 1020 as described with reference to FIGs. 9 and 10.
  • the transmitter 750 may utilize a single antenna or a set of antennas.
  • FIG. 8 shows a block diagram 800 of a dynamic list size decoder 805 that supports dynamic list size reduction for decoding polar codes in accordance with aspects of the present disclosure.
  • the dynamic list size decoder 805 may be an example of aspects of a dynamic list size decoder 615, a dynamic list size decoder 715, a dynamic list size decoder 910, or a dynamic list size decoder 1010 described herein.
  • the dynamic list size decoder 805 may include a decoding candidate reception component 810, a polar decoding component 815, a path metric determination component 820, an EDC bit identifier 825, an EDC operation component 830, a list size reduction component 835, an early termination component 840, a list size reduction threshold component 845, a lookup table component 850, and a path metric comparison component 855. Each of these modules may communicate, directly or indirectly, with one another (e.g., via one or more buses) .
  • the decoding candidate reception component 810 may receive a decoding candidate associated with a codeword, the codeword corresponding to a set of information bits encoded using a polar code.
  • the decoding candidate may correspond to a PDCCH transmission and the set of information bits may include DCI.
  • the polar decoding component 815 may perform a decoding process on the decoding candidate. This decoding process may include a number of functions, including those described with respect to other components as discussed herein.
  • the path metric determination component 820 may determine path metrics for each of a first set of decoding paths over a first subset of bit channels of the polar code, where the first set of decoding paths corresponds to a first list size.
  • the first list size is based on a capability of an SCL decoder performing the decoding process.
  • the EDC bit identifier 825 may identify an EDC bit of the set of information bits. In some examples, identifying the EDC bit of the set of information bits involves identifying a set of EDC bits of the set of information bits.
  • the EDC operation component 830 may perform an EDC operation on the first set of decoding paths using respective values of the EDC bit.
  • performing the EDC operation on the first set of decoding paths involves performing the EDC operation on the first set of decoding paths using respective sets of values of the set of EDC bits.
  • the EDC operation is an example of a CRC operation.
  • the list size reduction component 835 may determine path metrics for each of a second set of decoding paths over a second subset of bit channels of the polar code, where the second set of decoding paths corresponds to a second list size, and where the second list size is determined based on the first list size and a number of decoding paths of the first set of decoding paths that fail the EDC operation.
  • the EDC bit identifier 825 may identify a second EDC bit of the set of information bits.
  • the EDC operation component 830 may perform a second EDC operation on the second set of decoding paths using respective values of the second EDC bit.
  • the list size reduction component 835 may determine path metrics for each of a third set of decoding paths over a third subset of bit channels of the polar code, where the third set of decoding paths corresponds to a third list size, and where the third list size is determined based on the second list size and a number of decoding paths of the second set of decoding paths that fail the second EDC operation.
  • the early termination component 840 may identify that all decoding paths of the second set of decoding paths fail the second EDC operation and may terminate the decoding process based on the identifying that all the decoding paths of the second set of decoding paths fail the second EDC operation.
  • the list size reduction threshold component 845 may determine whether to reduce a list size for the decoding process from the first list size to the second list size based on a threshold value.
  • the threshold value may be a threshold DCI size.
  • the list size reduction threshold component 845 may determine an expected DCI size for the decoding candidate and may compare the expected DCI size for the decoding candidate to the threshold DCI size, where the list size for the decoding process is reduced if the expected DCI size for the decoding candidate is larger than the threshold DCI size.
  • the threshold value may be a threshold performance loss value.
  • the list size reduction threshold component 845 may store a lookup table in memory, the lookup table including estimated performance loss values for the decoding process for different combinations of numbers of information bits and codeword lengths.
  • the list size reduction threshold component 845 may identify an estimated performance loss value from the lookup table based on an expected number of information bits and expected codeword length for the decoding candidate and may compare the identified estimated performance loss value to the threshold performance loss value, where the list size for the decoding process is reduced if the identified estimated performance loss value is less than the threshold performance loss value.
  • the threshold value is preconfigured or is received in a configuration message.
  • the lookup table component 850 may store a lookup table in memory, the lookup table including a list size reduction enablement value for the decoding process for different combinations of numbers of information bits and codeword lengths. In some examples, the lookup table component 850 may determine whether to reduce a list size for the decoding process from the first list size to the second list size based on the stored lookup table.
  • the path metric comparison component 855 may compare one or more path metrics for decoding paths of the first set of decoding paths that fail the EDC operation with one or more path metrics for decoding paths of the first set of decoding paths that pass the EDC operation, and the path metric comparison component 855 may determine to reduce a list size for the decoding process from the first list size to the second list size based on the comparing.
  • Comparing the one or more path metrics for the decoding paths of the first set of decoding paths that fail the EDC operation with the one or more path metrics for the decoding paths of the first set of decoding paths that pass the EDC operation may include comparing a minimum path metric for the decoding paths of the first set of decoding paths that fail the EDC operation with a minimum path metric for the decoding paths of the first set of decoding paths that pass the EDC operation.
  • determining to reduce the list size for the decoding process may include determining to reduce the list size for the decoding process if the minimum path metric for the decoding paths of the first set of decoding paths that pass the EDC operation is less than the minimum path metric for the decoding paths of the first set of decoding paths that fail the EDC operation. In other examples, determining to reduce the list size for the decoding process may include determining to reduce the list size for the decoding process if a difference between the minimum path metric for the decoding paths of the first set of decoding paths that fail the EDC operation and the minimum path metric for the decoding paths of the first set of decoding paths that pass the EDC operation is greater than a path metric difference threshold.
  • FIG. 9 shows a diagram of a system 900 including a device 905 that supports dynamic list size reduction for decoding polar codes in accordance with aspects of the present disclosure.
  • the device 905 may be an example of or include the components of device 605, device 705, or a UE 115 as described herein.
  • the device 905 may include components for bi-directional voice and data communications including components for transmitting and receiving communications, including a dynamic list size decoder 910, a transceiver 920, an antenna 925, memory 930, a processor 940, and an I/O controller 950. These components may be in electronic communication via one or more buses (e.g., bus 955) .
  • buses e.g., bus 955
  • the dynamic list size decoder 910 may receive a decoding candidate associated with a codeword, the codeword corresponding to a set of information bits encoded using a polar code, and may perform a decoding process on the decoding candidate.
  • the decoding process may include determining path metrics for each of a first set of decoding paths over a first subset of bit channels of the polar code, where the first set of decoding paths corresponds to a first list size, identifying an EDC bit of the set of information bits, performing an EDC operation on the first set of decoding paths using respective values of the EDC bit, and determining path metrics for each of a second set of decoding paths over a second subset of bit channels of the polar code, where the second set of decoding paths corresponds to a second list size, and where the second list size is determined based on the first list size and a number of decoding paths of the first set of decoding paths that fail the EDC operation.
  • Transceiver 920 may communicate bi-directionally, via one or more antennas, wired, or wireless links as described above.
  • the transceiver 920 may represent a wireless transceiver and may communicate bi-directionally with another wireless transceiver.
  • the transceiver 920 may also include a modem to modulate the packets and provide the modulated packets to the antennas for transmission, and to demodulate packets received from the antennas.
  • the wireless device may include a single antenna 925. However, in some cases the device may have more than one antenna 925, which may be capable of concurrently transmitting or receiving multiple wireless transmissions.
  • the memory 930 may include random-access memory (RAM) , read-only memory (ROM) , or a combination thereof.
  • the memory 930 may store computer-readable code 935 including instructions that, when executed by a processor (e.g., the processor 940) cause the device to perform various functions described herein.
  • a processor e.g., the processor 940
  • the memory 930 may contain, among other things, a basic input/output system (BIOS) which may control basic hardware or software operation such as the interaction with peripheral components or devices.
  • BIOS basic input/output system
  • the processor 940 may include an intelligent hardware device (e.g., a general-purpose processor, a DSP, a central processing unit (CPU) , a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof) .
  • the processor 940 may be configured to operate a memory array using a memory controller.
  • a memory controller may be integrated into the processor 940.
  • the processor 940 may be configured to execute computer-readable instructions stored in a memory (e.g., the memory 930) to cause the device 905 to perform various functions (e.g., functions or tasks supporting dynamic list size reduction for decoding polar codes) .
  • the I/O controller 950 may manage input and output signals for the device 905.
  • the I/O controller 950 may also manage peripherals not integrated into the device 905.
  • the I/O controller 950 may represent a physical connection or port to an external peripheral.
  • the I/O controller 950 may utilize an operating system such as MS- MS- OS/ or another known operating system.
  • the I/O controller 950 may represent or interact with a modem, a keyboard, a mouse, a touchscreen, or a similar device.
  • the I/O controller 950 may be implemented as part of a processor.
  • a user may interact with the device 905 via the I/O controller 950 or via hardware components controlled by the I/O controller 950.
  • the code 935 may include instructions to implement aspects of the present disclosure, including instructions to support wireless communications.
  • the code 935 may be stored in a non-transitory computer-readable medium such as system memory or other type of memory. In some cases, the code 935 may not be directly executable by the processor 940 but may cause a computer (e.g., when compiled and executed) to perform functions described herein.
  • FIG. 10 shows a diagram of a system 1000 including a device 1005 that supports dynamic list size reduction for decoding polar codes in accordance with aspects of the present disclosure.
  • the device 1005 may be an example of or include the components of device 605, device 705, or a base station 105 as described herein.
  • the device 1005 may include components for bi-directional voice and data communications including components for transmitting and receiving communications, including a dynamic list size decoder 1010, a network communications manager 1015, a transceiver 1020, an antenna 1025, memory 1030, a processor 1040, and an inter-station communications manager 1045. These components may be in electronic communication via one or more buses (e.g., bus 1055) .
  • buses e.g., bus 1055
  • the dynamic list size decoder 1010 may receive a decoding candidate associated with a codeword, the codeword corresponding to a set of information bits encoded using a polar code, and may perform a decoding process on the decoding candidate.
  • the decoding process may involve determining path metrics for each of a first set of decoding paths over a first subset of bit channels of the polar code, where the first set of decoding paths corresponds to a first list size, identifying an EDC bit of the set of information bits, performing an EDC operation on the first set of decoding paths using respective values of the EDC bit, and determining path metrics for each of a second set of decoding paths over a second subset of bit channels of the polar code, where the second set of decoding paths corresponds to a second list size, and where the second list size is determined based on the first list size and a number of decoding paths of the first set of decoding paths that fail the EDC operation.
  • Network communications manager 1015 may manage communications with the core network 130 (e.g., via one or more wired backhaul links) .
  • the network communications manager 1015 may manage the transfer of data communications for client devices, such as one or more UEs 115.
  • Transceiver 1020 may communicate bi-directionally, via one or more antennas, wired, or wireless links as described above.
  • the transceiver 1020 may represent a wireless transceiver and may communicate bi-directionally with another wireless transceiver.
  • the transceiver 1020 may also include a modem to modulate the packets and provide the modulated packets to the antennas for transmission, and to demodulate packets received from the antennas.
  • the wireless device may include a single antenna 1025. However, in some cases the device may have more than one antenna 1025, which may be capable of concurrently transmitting or receiving multiple wireless transmissions.
  • the memory 1030 may include RAM, ROM, or a combination thereof.
  • the memory 1030 may store computer-readable code 1035 including instructions that, when executed by a processor (e.g., the processor 1040) cause the device to perform various functions described herein.
  • a processor e.g., the processor 1040
  • the memory 1030 may contain, among other things, a BIOS which may control basic hardware or software operation such as the interaction with peripheral components or devices.
  • the processor 1040 may include an intelligent hardware device (e.g., a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof) .
  • the processor 1040 may be configured to operate a memory array using a memory controller.
  • a memory controller may be integrated into the processor 1040.
  • the processor 1040 may be configured to execute computer-readable instructions stored in a memory (e.g., the memory 1030) to cause the device 1005 to perform various functions (e.g., functions or tasks supporting dynamic list size reduction for decoding polar codes) .
  • Inter-station communications manager 1045 may manage communications with other base station 105 and may include a controller or scheduler for controlling communications with UEs 115 in cooperation with other base stations 105. For example, the inter-station communications manager 1045 may coordinate scheduling for transmissions to UEs 115 for various interference mitigation techniques such as beamforming or joint transmission. In some examples, inter-station communications manager 1045 may provide an X2 interface within an LTE/LTE-A wireless communication network technology to provide communication between base stations 105.
  • the code 1035 may include instructions to implement aspects of the present disclosure, including instructions to support wireless communications.
  • the code 1035 may be stored in a non-transitory computer-readable medium such as system memory or other type of memory. In some cases, the code 1035 may not be directly executable by the processor 1040 but may cause a computer (e.g., when compiled and executed) to perform functions described herein.
  • FIG. 11 shows a flowchart illustrating a method 1100 that supports dynamic list size reduction for decoding polar codes in accordance with aspects of the present disclosure.
  • the operations of method 1100 may be implemented by a UE 115 or base station 105 or its components as described herein.
  • the operations of method 1100 may be performed by a dynamic list size decoder as described with reference to FIGs. 6 through 10.
  • a UE or base station may execute a set of instructions to control the functional elements of the UE or base station to perform the functions described below. Additionally or alternatively, a UE or base station may perform aspects of the functions described below using special-purpose hardware.
  • the UE or base station may receive a decoding candidate associated with a codeword, the codeword corresponding to a set of information bits encoded using a polar code.
  • the operations of 1105 may be performed according to the methods described herein. In some examples, aspects of the operations of 1105 may be performed by a decoding candidate reception component as described with reference to FIGs. 6 through 10.
  • the UE or base station may perform a decoding process on the decoding candidate.
  • this decoding process may include the functions described below with respect to 1115 through 1130.
  • the operations of 1110 may be performed according to the methods described herein. In some examples, aspects of the operations of 1110 may be performed by a polar decoding component as described with reference to FIGs. 6 through 10.
  • the UE or base station may determine path metrics for each of a first set of decoding paths over a first subset of bit channels of the polar code, where the first set of decoding paths corresponds to a first list size.
  • the operations of 1115 may be performed according to the methods described herein. In some examples, aspects of the operations of 1115 may be performed by a path metric determination component as described with reference to FIGs. 6 through 10.
  • the UE or base station may identify an EDC bit (e.g., a single bit or a set of bits) of the set of information bits.
  • the operations of 1120 may be performed according to the methods described herein. In some examples, aspects of the operations of 1120 may be performed by an EDC bit identifier as described with reference to FIGs. 6 through 10.
  • the UE or base station may perform an EDC operation on the first set of decoding paths using respective values of the EDC bit.
  • the operations of 1125 may be performed according to the methods described herein. In some examples, aspects of the operations of 1125 may be performed by an EDC operation component as described with reference to FIGs. 6 through 10.
  • the UE or base station may determine path metrics for each of a second set of decoding paths over a second subset of bit channels of the polar code, where the second set of decoding paths corresponds to a second list size, and where the second list size is determined based on the first list size and a number of decoding paths of the first set of decoding paths that fail the EDC operation.
  • the operations of 1130 may be performed according to the methods described herein. In some examples, aspects of the operations of 1130 may be performed by a list size reduction component as described with reference to FIGs. 6 through 10.
  • FIG. 12 shows a flowchart illustrating a method 1200 that supports dynamic list size reduction for decoding polar codes in accordance with aspects of the present disclosure.
  • the operations of method 1200 may be implemented by a UE 115 (e.g., in the case of decoding a PDCCH transmission) or a base station 105 or its components as described herein.
  • the operations of method 1200 may be performed by a dynamic list size decoder as described with reference to FIGs. 6 through 10.
  • a UE or base station may execute a set of instructions to control the functional elements of the UE or base station to perform the functions described below. Additionally or alternatively, a UE or base station may perform aspects of the functions described below using special-purpose hardware.
  • the UE or base station may receive a decoding candidate associated with a codeword, the codeword corresponding to a set of information bits encoded using a polar code.
  • the operations of 1205 may be performed according to the methods described herein. In some examples, aspects of the operations of 1205 may be performed by a decoding candidate reception component as described with reference to FIGs. 6 through 10.
  • the UE or base station may perform a decoding process on the decoding candidate.
  • This decoding process may include the processes described below with respect to 1215 through 1250.
  • the operations of 1210 may be performed according to the methods described herein. In some examples, aspects of the operations of 1210 may be performed by a polar decoding component as described with reference to FIGs. 6 through 10.
  • the UE or base station may determine path metrics for each of a first set of decoding paths over a first subset of bit channels of the polar code, where the first set of decoding paths corresponds to a first list size.
  • the operations of 1215 may be performed according to the methods described herein. In some examples, aspects of the operations of 1215 may be performed by a path metric determination component as described with reference to FIGs. 6 through 10.
  • the UE or base station may identify an EDC bit of the set of information bits.
  • the operations of 1220 may be performed according to the methods described herein. In some examples, aspects of the operations of 1220 may be performed by an EDC bit identifier as described with reference to FIGs. 6 through 10.
  • the UE or base station may perform an EDC operation on the first set of decoding paths using respective values of the EDC bit.
  • the operations of 1225 may be performed according to the methods described herein. In some examples, aspects of the operations of 1225 may be performed by an EDC operation component as described with reference to FIGs. 6 through 10.
  • the UE or base station may determine path metrics for each of a second set of decoding paths over a second subset of bit channels of the polar code, where the second set of decoding paths corresponds to a second list size, and where the second list size is determined based on the first list size and a number of decoding paths of the first set of decoding paths that fail the EDC operation.
  • the operations of 1230 may be performed according to the methods described herein. In some examples, aspects of the operations of 1230 may be performed by a list size reduction component as described with reference to FIGs. 6 through 10.
  • the UE or base station may identify a second EDC bit of the set of information bits.
  • the operations of 1235 may be performed according to the methods described herein. In some examples, aspects of the operations of 1235 may be performed by an EDC bit identifier as described with reference to FIGs. 6 through 10.
  • the UE or base station may perform a second EDC operation on the second set of decoding paths using respective values of the second EDC bit.
  • the operations of 1240 may be performed according to the methods described herein. In some examples, aspects of the operations of 1240 may be performed by an EDC operation component as described with reference to FIGs. 6 through 10.
  • the UE or base station may identify that all decoding paths of the second set of decoding paths fail the second EDC operation.
  • the operations of 1245 may be performed according to the methods described herein. In some examples, aspects of the operations of 1245 may be performed by an early termination component as described with reference to FIGs. 6 through 10.
  • the UE or base station may terminate the decoding process based on identifying that all the decoding paths of the second set of decoding paths fail the second EDC operation.
  • the operations of 1250 may be performed according to the methods described herein. In some examples, aspects of the operations of 1250 may be performed by an early termination component as described with reference to FIGs. 6 through 10.
  • FIG. 13 shows a flowchart illustrating a method 1300 that supports dynamic list size reduction for decoding polar codes in accordance with aspects of the present disclosure.
  • the operations of method 1300 may be implemented by a UE 115 or base station 105 or its components as described herein.
  • the operations of method 1300 may be performed by a dynamic list size decoder as described with reference to FIGs. 6 through 10.
  • a UE or base station may execute a set of instructions to control the functional elements of the UE or base station to perform the functions described below. Additionally or alternatively, a UE or base station may perform aspects of the functions described below using special-purpose hardware.
  • the UE or base station may receive a decoding candidate associated with a codeword, the codeword corresponding to a set of information bits encoded using a polar code.
  • the operations of 1305 may be performed according to the methods described herein. In some examples, aspects of the operations of 1305 may be performed by a decoding candidate reception component as described with reference to FIGs. 6 through 10.
  • the UE or base station may perform a decoding process on the decoding candidate.
  • This decoding process may include the processes described below with respect to 1315 through 1335.
  • the operations of 1310 may be performed according to the methods described herein. In some examples, aspects of the operations of 1310 may be performed by a polar decoding component as described with reference to FIGs. 6 through 10.
  • the UE or base station may determine path metrics for each of a first set of decoding paths over a first subset of bit channels of the polar code, where the first set of decoding paths corresponds to a first list size.
  • the operations of 1315 may be performed according to the methods described herein. In some examples, aspects of the operations of 1315 may be performed by a path metric determination component as described with reference to FIGs. 6 through 10.
  • the UE or base station may identify an EDC bit of the set of information bits.
  • the operations of 1320 may be performed according to the methods described herein. In some examples, aspects of the operations of 1320 may be performed by an EDC bit identifier as described with reference to FIGs. 6 through 10.
  • the UE or base station may perform an EDC operation on the first set of decoding paths using respective values of the EDC bit.
  • the operations of 1325 may be performed according to the methods described herein. In some examples, aspects of the operations of 1325 may be performed by an EDC operation component as described with reference to FIGs. 6 through 10.
  • the UE or base station may determine whether to reduce a list size for the decoding process from the first list size to a second list size based on a threshold value.
  • the operations of 1330 may be performed according to the methods described herein. In some examples, aspects of the operations of 1330 may be performed by a list size reduction threshold component as described with reference to FIGs. 6 through 10.
  • the UE or base station may determine path metrics for each of a second set of decoding paths over a second subset of bit channels of the polar code, where the second set of decoding paths corresponds to the second list size, and where the second list size is determined based on the first list size and a number of decoding paths of the first set of decoding paths that fail the EDC operation.
  • the operations of 1335 may be performed according to the methods described herein. In some examples, aspects of the operations of 1335 may be performed by a list size reduction component as described with reference to FIGs. 6 through 10.
  • FIG. 14 shows a flowchart illustrating a method 1400 that supports dynamic list size reduction for decoding polar codes in accordance with aspects of the present disclosure.
  • the operations of method 1400 may be implemented by a UE 115 or base station 105 or its components as described herein.
  • the operations of method 1400 may be performed by a dynamic list size decoder as described with reference to FIGs. 6 through 10.
  • a UE or base station may execute a set of instructions to control the functional elements of the UE or base station to perform the functions described below. Additionally or alternatively, a UE or base station may perform aspects of the functions described below using special-purpose hardware.
  • the UE or base station may receive a decoding candidate associated with a codeword, the codeword corresponding to a set of information bits encoded using a polar code.
  • the operations of 1405 may be performed according to the methods described herein. In some examples, aspects of the operations of 1405 may be performed by a decoding candidate reception component as described with reference to FIGs. 6 through 10.
  • the UE or base station may perform a decoding process on the decoding candidate.
  • This decoding process may include the processes described below with respect to 1415 through 1440.
  • the operations of 1410 may be performed according to the methods described herein. In some examples, aspects of the operations of 1410 may be performed by a polar decoding component as described with reference to FIGs. 6 through 10.
  • the UE or base station may determine path metrics for each of a first set of decoding paths over a first subset of bit channels of the polar code, where the first set of decoding paths corresponds to a first list size.
  • the operations of 1415 may be performed according to the methods described herein. In some examples, aspects of the operations of 1415 may be performed by a path metric determination component as described with reference to FIGs. 6 through 10.
  • the UE or base station may identify an EDC bit of the set of information bits.
  • the operations of 1420 may be performed according to the methods described herein. In some examples, aspects of the operations of 1420 may be performed by an EDC bit identifier as described with reference to FIGs. 6 through 10.
  • the UE or base station may perform an EDC operation on the first set of decoding paths using respective values of the EDC bit.
  • the operations of 1425 may be performed according to the methods described herein. In some examples, aspects of the operations of 1425 may be performed by an EDC operation component as described with reference to FIGs. 6 through 10.
  • the UE or base station may compare one or more path metrics for decoding paths of the first set of decoding paths that fail the EDC operation with one or more path metrics for decoding paths of the first set of decoding paths that pass the EDC operation.
  • the operations of 1430 may be performed according to the methods described herein. In some examples, aspects of the operations of 1430 may be performed by a path metric comparison component as described with reference to FIGs. 6 through 10.
  • the UE or base station may determine to reduce a list size for the decoding process from the first list size to a second list size based on the comparing.
  • the operations of 1435 may be performed according to the methods described herein. In some examples, aspects of the operations of 1435 may be performed by a path metric comparison component as described with reference to FIGs. 6 through 10.
  • the UE or base station may determine path metrics for each of a second set of decoding paths over a second subset of bit channels of the polar code, where the second set of decoding paths corresponds to the second list size, and where the second list size is determined based on the first list size and a number of decoding paths of the first set of decoding paths that fail the EDC operation.
  • the operations of 1440 may be performed according to the methods described herein. In some examples, aspects of the operations of 1440 may be performed by a list size reduction component as described with reference to FIGs. 6 through 10.
  • CDMA code division multiple access
  • TDMA time division multiple access
  • FDMA frequency division multiple access
  • OFDMA orthogonal frequency division multiple access
  • SC-FDMA single carrier frequency division multiple access
  • a CDMA system may implement a radio technology such as CDMA2000, Universal Terrestrial Radio Access (UTRA) , etc.
  • CDMA2000 covers IS-2000, IS-95, and IS-856 standards.
  • IS-2000 Releases may be commonly referred to as CDMA2000 1X, 1X, etc.
  • IS-856 TIA-856) is commonly referred to as CDMA2000 1xEV-DO, High Rate Packet Data (HRPD) , etc.
  • UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA.
  • a TDMA system may implement a radio technology such as Global System for Mobile Communications (GSM) .
  • GSM Global System for Mobile Communications
  • An OFDMA system may implement a radio technology such as Ultra Mobile Broadband (UMB) , Evolved UTRA (E-UTRA) , Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi) , IEEE 802.16 (WiMAX) , IEEE 802.20, Flash-OFDM, etc.
  • UMB Ultra Mobile Broadband
  • E-UTRA Evolved UTRA
  • IEEE Institute of Electrical and Electronics Engineers
  • Wi-Fi Institute of Electrical and Electronics Engineers
  • IEEE 802.16 WiMAX
  • IEEE 802.20 Flash-OFDM
  • UTRA and E-UTRA are part of Universal Mobile Telecommunications System (UMTS) .
  • LTE, LTE-A, and LTE-A Pro are releases of UMTS that use E-UTRA.
  • UTRA, E-UTRA, UMTS, LTE, LTE-A, LTE-A Pro, NR, and GSM are described in documents from the organization named “3rd Generation Partnership Project” (3GP
  • CDMA2000 and UMB are described in documents from an organization named “3rd Generation Partnership Project 2” (3GPP2) .
  • 3GPP2 3rd Generation Partnership Project 2
  • the techniques described herein may be used for the systems and radio technologies mentioned herein as well as other systems and radio technologies. While aspects of an LTE, LTE-A, LTE-A Pro, or NR system may be described for purposes of example, and LTE, LTE-A, LTE-A Pro, or NR terminology may be used in much of the description, the techniques described herein are applicable beyond LTE, LTE-A, LTE-A Pro, or NR applications.
  • a macro cell generally covers a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs 115 with service subscriptions with the network provider.
  • a small cell may be associated with a lower-powered base station 105, as compared with a macro cell, and a small cell may operate in the same or different (e.g., licensed, unlicensed, etc. ) frequency bands as macro cells.
  • Small cells may include pico cells, femto cells, and micro cells according to various examples.
  • a pico cell for example, may cover a small geographic area and may allow unrestricted access by UEs 115 with service subscriptions with the network provider.
  • a femto cell may also cover a small geographic area (e.g., a home) and may provide restricted access by UEs 115 having an association with the femto cell (e.g., UEs 115 in a closed subscriber group (CSG) , UEs 115 for users in the home, and the like) .
  • An eNB for a macro cell may be referred to as a macro eNB.
  • An eNB for a small cell may be referred to as a small cell eNB, a pico eNB, a femto eNB, or a home eNB.
  • An eNB may support one or multiple (e.g., two, three, four, and the like) cells, and may also support communications using one or multiple component carriers.
  • the wireless communications system 100 or systems described herein may support synchronous or asynchronous operation.
  • the base stations 105 may have similar frame timing, and transmissions from different base stations 105 may be approximately aligned in time.
  • the base stations 105 may have different frame timing, and transmissions from different base stations 105 may not be aligned in time.
  • the techniques described herein may be used for either synchronous or asynchronous operations.
  • Information and signals described herein may be represented using any of a variety of different technologies and techniques.
  • data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.
  • a general-purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine.
  • a processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration) .
  • the functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Other examples and implementations are within the scope of the disclosure and appended claims. For example, due to the nature of software, functions described herein can be implemented using software executed by a processor, hardware, firmware, hardwiring, or combinations of any of these. Features implementing functions may also be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations.
  • Computer-readable media includes both non-transitory computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another.
  • a non-transitory storage medium may be any available medium that can be accessed by a general purpose or special purpose computer.
  • non-transitory computer-readable media may include RAM, ROM, electrically erasable programmable read only memory (EEPROM) , flash memory, compact disk (CD) ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other non-transitory medium that can be used to carry or store desired program code means in the form of instructions or data structures and that can be accessed by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor.
  • RAM random access memory
  • ROM read only memory
  • EEPROM electrically erasable programmable read only memory
  • CD compact disk
  • magnetic disk storage or other magnetic storage devices or any other non-transitory medium that can be used to carry or store desired program code means in the form
  • any connection is properly termed a computer-readable medium.
  • the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL) , or wireless technologies such as infrared, radio, and microwave
  • the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium.
  • Disk and disc include CD, laser disc, optical disc, digital versatile disc (DVD) , floppy disk and Blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above are also included within the scope of computer-readable media.

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Abstract

La présente invention concerne des procédés, des systèmes et des dispositifs pour des communications sans fil. Dans certains systèmes, des dispositifs sans fil peuvent utiliser des codes polaires pour coder des transmissions. Un dispositif recevant des candidats de décodage pour un mot de code codé polaire peut réaliser un processus de décodage à l'aide d'une procédure de réduction dynamique de taille de liste. À l'aide d'un décodeur de liste, le dispositif peut déterminer des métriques de chemin pour un premier ensemble de chemins de décodage dans un premier sous-ensemble de canaux binaires selon une taille initiale de la liste. Lorsque le décodeur identifie un bit de contrôle de détection d'erreurs (EDC), le décodeur peut réaliser une opération EDC pour le premier ensemble de chemins de décodage à l'aide de valeurs respectives du bit EDC. Le décodeur peut élaguer des chemins de décodage qui échouent à l'opération EDC et peut réduire la taille effective de la liste à décoder en enlevant le nombre de chemins de décodage ayant échoué. Le décodeur peut continuer le processus de décodage à l'aide de cette taille de liste réduite, ce qui permet d'obtenir une complexité de décodage réduite.
PCT/CN2018/108422 2018-09-28 2018-09-28 Réduction de complexité pour décodage de liste d'annulation séquentielle de codes polaires Ceased WO2020062061A1 (fr)

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WO2025038286A1 (fr) * 2023-08-16 2025-02-20 Qualcomm Incorporated Opérations de décodage en liste efficaces en ressources
US12301256B2 (en) 2023-08-16 2025-05-13 Qualcomm Incorporated Resource efficient list decoding operations

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