HK1243841B - Harq-ack handling method for unintended downlink sub-frames - Google Patents

Description

HARQ-ACK handling method for unexpected downlink subframes

Background Art

Long Term Evolution (LTE) and other wireless networks rely on messaging across an unreliable medium between mobile devices (e.g., user equipment (UE)) and the radio access network (RAN). In LTE, the RAN consists of one or more eNodeBs (evolved Node Bs). This unreliable communication medium can create problems for proper data communication between the RAN and the UE, as data can be lost or corrupted due to low signal quality, interference, or other issues with the wireless medium.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a table showing mapping of HARQ-ACK responses to resources, constellations, and RM code input bits for two cells with 3 bundling windows according to some examples of the present disclosure.

2 is a table showing mapping from HARQ-ACK responses to resources, constellations, and RM code input bits for two cells with a 4-bundling window according to some examples of the present disclosure.

FIG. 2A is a continuation of the table of FIG. 2 according to some examples of the present disclosure.

FIG3 shows a diagram of example resource allocations according to some examples of the present disclosure.

FIG4 shows a diagram of example resource allocations according to some examples of the present disclosure.

FIG5A shows a flowchart of a method of generating a HARQ-ACK response according to some examples of the present disclosure.

FIG5B shows a flowchart of a method of processing a HARQ-ACK response according to some examples of the present disclosure.

FIG6 illustrates a block diagram of a wireless communication system according to some examples of the present disclosure.

FIG7 shows a functional block diagram illustrating certain functions of a UE and an eNodeB according to some examples of the present disclosure.

FIG8 shows a block diagram of a machine according to some examples of the present disclosure.

DETAILED DESCRIPTION

To combat unreliable wireless communication media, LTE and other cellular networks employ a mechanism known as Hybrid Automatic Repeat Request (HARQ) to provide error correction and packet acknowledgment to ensure secure data delivery between the RAN and UEs. HARQ uses forward error correction (FEC) and an automatic feedback mechanism (Automatic Repeat Request (ARQ)) to provide error correction at the receiver side, indicating to the transmitter whether a packet has been successfully received. Upon receiving a data packet, the receiver uses an error detection code (e.g., a cyclic redundancy check (CRC)) to determine whether the packet was received correctly. If the packet was received successfully, the receiver uses a feedback mechanism (e.g., an ACK) to acknowledge the sender. If the packet was not received successfully, the receiver may attempt to repair the packet using the FEC information. If the receiver successfully repairs the packet using the FEC information, it may ACK the sender; otherwise, the receiver may respond with a negative acknowledgment (NACK). In yet another example, the receiver (UE) may respond that it is in discontinuous transmission (DTX) mode. A DTX response may indicate that the UE is unable to properly detect information on a control channel (e.g., the Primary Downlink Control Channel (PDCCH)) and, therefore, cannot determine whether a packet was sent to the UE.

In cellular networks, these HARQ responses are typically transmitted on a control channel. Responses to downlink traffic sent from the RAN to the UE are typically sent on an uplink control channel (e.g., the Physical Uplink Control Channel (PUCCH)). Responses to uplink traffic sent from the UE to the RAN are typically sent on a downlink HARQ-ACK channel (e.g., the Physical Hybrid HARQ Indicator Channel: PHICH). Packets that are not acknowledged (either NACKed or simply not acknowledged at all) may be retransmitted by the sender.

In some systems, uplink communications (from the UE to the RAN) are separated from downlink communications in the frequency domain. That is, uplink and downlink wireless communications occur on different frequency bands. These systems are referred to as frequency division duplex (FDD) systems. In other examples, uplink and downlink wireless communications may share the same frequency band but may be separated in the time domain. That is, the frequency band is reserved for uplink wireless transmissions in some time instances (e.g., referred to as time slots) and downlink wireless communications in other time instances (e.g., time slots). This scheme is referred to as time division duplex (TDD). In yet another example, a half-duplex FDD (H-FDD) system features uplink and downlink wireless communications on different frequency bands, but also separated in the time domain.

The very nature of cellular networks is that communications between the UE and the RAN are asymmetric, favoring the downlink radio link. That is, typically more data is sent from the RAN to the UE than from the UE to the RAN. To compensate for this, cell planners will often allocate more frequency or time resources (depending on whether the network is FDD or TDD) to downlink radio communications than to uplink radio communications.

This resource asymmetry creates problems for UEs trying to manage the necessary HARQ acknowledgments, as uplink resources on the uplink control channel are often insufficient to transmit these responses.This problem is only exacerbated with the addition of multiple carriers and other uplink signaling (eg, channel state information).

In LTE, wireless transmissions are typically broken down into discrete units called frames, which can then be broken down into subframes and subframes into one or more codewords. Each codeword can be mapped to a specific transport block and are used interchangeably herein (unless otherwise specified). With FDD systems, a fixed number of subframes can be used to transmit an HARQ response after receiving a transmission (typically four subframes later). However, with TDD systems, a fixed delay is not possible due to the variable number of uplink and downlink time slots in a radio frame, often caused by asymmetric radio imbalance.

To address these issues, the Third Generation Partnership Project (3GPP), which published the 4G (LTE) wireless network standard for TDD systems, has developed several mechanisms. The first is ACK/NACK/DTX time-domain bundling. With HARQ-ACK bundling, the ACK, NACK, or DTX results for each specific codeword received in each downlink subframe of a specific number of subframes (referred to as the bundling window) on a downlink channel (e.g., the Physical Downlink Shared Channel (PDSCH)) are logically ANDed together to produce one or more composite results corresponding to each codeword in all subframes within the bundling window. The number of composite ACK/NACK/DTX results generated is equal to the number of codewords in the subframe. For example, if the bundling window size is four downlink subframes, and each subframe has two codewords, then the ACKs for the first codeword in subframes 0-3 are logically ANDed together, and the second codeword in subframes 0-3 are also logically ANDed together to produce two ACK bits. The benefit of this technique is that it is very compact, using very few bits to ensure uplink coverage. The drawback is that if any codeword in any subframe is not received correctly, the specific codeword will be retransmitted for all subframes. Another technique uses HARQ-ACK multiplexing, which logically ANDs the codewords across each downlink subframe individually (referred to as spatial-domain bundling) to produce one ACK bit per downlink subframe. The result is an ACK/NACK/DTX result for each associated downlink subframe within the bundling window. For the four downlink subframes with two codewords per subframe, spatial-domain bundling (if any) across the two codewords is applied within the subframe using a logical-AND operation, and multiple bundled ACK/NACKs within the subframe result in a composite state within the bundling window. For the HARQ-ACK response sent on the Physical Uplink Control Channel (PUCCH), the composite state can be represented as a combination of PUCCH resources and constellation points. This results in four ACK results—one for each subframe. Note that although this specific HARQ-ACK technique is named "multiplexing," the term "bundling window" is used throughout this specification.

The bundling window is a time unit (e.g., a number of subframes) that specifies when HARQ-ACK feedback corresponding to downlink traffic at a specific uplink subframe is transmitted in the uplink. The UE uses the PUCCH to transmit HARQ-ACK feedback in subframes where HARQ-ACK feedback is used for (defined in Table 1) and (defined in Table 1). The bundling window is generally defined as the downlink subframe used for uplink HARQ-ACK feedback at subframes.

Table 1. Downlink association set index for TDD

The TDD UL-DL configuration table is given in Table 2.

Table 2 TDD UL-DL configuration

TDD uplink/downlink configuration (D=downlink, S=special subframe with three fields DwPTS, GP and UpPTS, which is used to give the UE time to switch from downlink to uplink, U=uplink).

LTE-Advanced supports carrier aggregation, where multiple carriers can be utilized in the downlink. This means that multiple ACK/NACK information bits for multiple carriers need to be fed back in the uplink. For this purpose, LTE defines a technique called channel selection with time-domain bundling. This technique utilizes a similar technique to HARQ-ACK multiplexing, except that the time-domain bundling used in this technique differs slightly from existing methods. Time-domain bundling for carrier aggregation can be used to transmit multiple consecutive ACKs for each component carrier, while time-domain bundling for a single carrier is used to transmit logically bundled HARQ-ACK information. The resulting ACK/NACK information is encoded using a combination of channel and QPSK constellation symbol selection. Essentially, the multiplexed ACK result can then be indexed into a lookup table to select a two-bit field (QPSK constellation) and PUCCH resource (selected channel) for PUCCH transmission. When HARQ-ACK is transported on the PUSCH, the RM code input bit settings are also provided. Mapping tables for different bundling window sizes are shown in Figures 1 and 2 (Figure 2 continues from Figure 2A). The columns labeled HARQ-ACK (0)-(2) of Figure 1 and the columns labeled HARQ-ACK (0)-(3) of Figures 2 and 2A represent the ACK, NACK, or DTX decision for that particular subframe for both the primary cell and the secondary cell (PCell and SCell, respectively). For example, in the case of a four subframe bundling window, if subframe (0) is successfully received (ACK), subframe (1) is not successfully received (NACK), subframe (2) is successfully received (ACK), and subframe (3) is successfully received (ACK) on the primary cell and a response of ACK, ACK, ACK, NACK on the secondary cell, the UE selects a constellation of (0, 1) with feedback resources corresponding to physical uplink control channel (PUCCH) 3 and using code input bits of 0, 0, 1, 1. In short, the HARQ-ACK(j) column is the ACK/NACK/or DTX response for each specific downlink subframe to be used for the primary cell and the secondary cell (for multiple carriers) and the corresponding PUCCH resources, constellations, and RM code input bits depending on the HARQ-ACK(j) selected for each of the primary and secondary cells. When PUCCH is used to transmit HARQ-ACK, this technique utilizes PUCCH format 1b.

If the UE does not correctly receive the scheduling information for any scheduled frame, HARQ-ACK bundling or HARQ-ACK multiplexing may not function properly. For example, if the eNodeB schedules two subframes with a bundling window size of 2 to a terminal, but the UE only receives the last frame, unaware that it was already scheduled in the first frame, the UE replies with an ACK. The eNodeB interprets this ACK as an acknowledgement of both subframes. To determine when a downlink grant for a UE has been missed, the LTE specification provides a Downlink Assignment Index (DAI) that is sent from the RAN to the UE along with the downlink scheduling information on the PDCCH. The DAI carried in the downlink grant is degraded until the cumulative number of PDCCHs with assigned PDSCH transmissions and PDCCHs indicating semi-persistent scheduling (SPS) release for the current subframe within the same bundling window for each configured serving cell is reached. The UE then uses the DAI to generate a HARQ-ACK (j) within the bundling window.

Turning now to Figure 3, an example response calculation is shown. In the example of Figure 3, a bundling window of four subframes ( M=4 ) is shown in two configured cells. The HARQ-ACK( j ) responses for the primary cell (PCell) are ACK, ACK, DTX, ACK, and for the secondary cell (SCell), they are ACK, NACK, NACK, ACK, respectively. The DAI received on the PDCCH of the PCell is 1 for subframe 0, 2 for subframe 1, and 4 for subframe 3. Note that the UE cannot decode the PDCCH in subframe 2 (m=2) and therefore does not update its DAI value. Even though the UE misses the updated DAI value, it recovers the DAI value in subframe m=3 and thus knows that the DAI is 4 at the end of the bundling window. Since the DAI value is 4, the UE knows that it requires four HARQ-ACK( j ) responses. For the SCell, the DAI received on the PDCCH is 1, 2, 3, and 4 for subframes 0, 1, 2, and 3, respectively.

Based on the mapping tables in Figures 2 and 2A, this produces the response:

Note that there is a problem when the RAN does not schedule all subframes of a particular bundling window. Since some frames are not scheduled, the DAI will not increment and will be less than the bundling window size at the end of the bundling window. The feedback tables of Figures 1 and 2 assume that all frames are scheduled. Figure 4 shows an example of this problem. In this example, the first two downlink subframes in the PCell are not scheduled. Therefore, for subframe 2, the DAI is 1, and for subframe 3, the DAI is 2 (compared to Figure 3, where the DAIs for subframes 2 and 3 are 3 and 4, respectively). Since HARQ-ACK( j ) is determined in conjunction with the DAI value, HARQ-ACK(0) corresponds to subframe 2 and HARQ-ACK(1) corresponds to subframe 3. However, since there are no corresponding DAI values 3 and 4 within the bundling window according to the definition of DAI, HARQ-ACK(2) and HARQ-ACK(3) are undefined. This is because the DAI value is defined as the cumulative number of PDCCHs in assigned PDSCH transmissions and PDCCHs indicating semi-persistent scheduling (SPS) releases up to the current subframe within the bundling window. Therefore, if there are no expected DL subframes to be monitored by the UE for HARQ-ACK associated with the DAI value within the bundling window ( j ), the UE behavior is not specified.

Disclosed in some examples are systems, methods, UEs, and machine-readable media that address the problem of generating acknowledgments for situations where the last received DAI (LDAI) value is less than the size of the bundling window. In some examples, for situations where LDAI <= j < M-1, predetermined states are utilized for HARQ-ACK( j ), where M is the multiplexing or bundling window size. For example, a DTX state may be padded into these HARQ-ACK responses. Thus, for example, in Figure 4, the HARQ-ACK( j ) for the PCell used to determine the appropriate response parameters would be: ACK, ACK, DTX, DTX.

Because DTX fills the last two states of the PCell, the UE knows the exact mapping to use from the table. Furthermore, on the network side, since the eNodeB already knows to fill the last two states with DTX, irrelevant states other than DTX can be excluded during PUCCH detection hypothesis testing, which can improve HARQ-ACK detection performance. For example, in Figure 3, since the HARQ-ACK responses in the PCell are {ACK, ACK, DTX, DTX}, {ACK, NACK, DTX, DTX}, {NACK, ACK, DTX, DTX}, or {NACK, NACK, DTX, DTX}, the states {Any, Any, ACK/NACK, ACK/NACK} can be excluded from eNB detection. By reducing detection hypothesis testing, PUCCH detection performance can be enhanced.

Applying this method to the example shown in Figure 4 produces:

While in some examples, HARQ-ACK( j ) may be filled with DTX for cases where not all downlink subframes within the bundled window are scheduled, in other examples, other values may be used, such as ACK, NACK, or another defined value. This is because the eNodeB has sufficient system knowledge to ignore these values. In fact, in some examples, the UE may arbitrarily select any ACK/NACK/DTX value.

Turning now to FIG. 5A , a method 5000 for acknowledging transmission when not all downlink frames within a particular bundling window are scheduled is illustrated. At operation 5010, the UE receives scheduling information on the PDCCH indicating scheduled downlink frames. At operation 5020, the UE determines that it has received the last downlink assignment for the particular bundling window and, at operation 5030, determines that the last DAI value (LDAI) is less than the bundling window size. At operation 5040, the UE determines an ACK/NACK/DTX response for the frame for which the UE is aware of being scheduled. At operation 5050, the remaining HARQ-ACKs ( j ) without corresponding DAI values are padded with a predetermined value (e.g., DTX).

Turning now to FIG. 5B , a method 5100 for handling acknowledgments at an eNodeB is illustrated in which transmissions of all downlink frames within a particular bundling window are not scheduled. At operation 5110, a base station (e.g., an eNodeB) may schedule one or more downlink transmissions for a particular acknowledgment period (e.g., a bundling window) and notify the UE via a downlink control channel (e.g., a physical downlink control channel (PDCCH)). At operation 5120, the eNodeB may transmit the scheduled frames. At operation 5130, the eNodeB may receive a response from the UE. At operation 5140, the eNodeB may determine that the last DAI value sent on the PDCCH is less than the bundling window size. At operation 5150, the eNodeB may determine the response using the resources (e.g., PUCCH resources) on which the response was received, along with the received constellation and RM code bits, taking into account that HARQ-ACK( j ) is a padded value, where j is LDAI <= j < M-1, where M is the multiplexing or bundling window size. The eNodeB may then transmit any necessary retransmissions.

Turning now to FIG. 6 , a system 6000 for acknowledging transmission is shown. A user equipment (UE) 6010 communicates with a radio access network (RAN) 6020 over one or more radio links 6040. The RAN 6020 may include one or more base stations (e.g., eNodeBs) 6030 and 6035. The RAN 6020 may be connected to a core network 6045, such as an enhanced packet core. The EPC 6045 may be connected to a network 6050, such as the Internet, plain old telephone service (POTS), or the like. In the system of FIG. 6 , the radio link 6040 may operate in a time division duplex (TDD) mode.

FIG7 illustrates a partial functional diagram of a UE 7000 (which may include further components not shown). UE 7000 may include a transmit module 7010. Transmit module 7010 may transmit control and user traffic to the RAN over one or more uplink channels (e.g., the Physical Uplink Control Channel (PUCCH), the Physical Uplink Shared Channel (PUSCH), etc.). Transmit module 7010 may also transmit acknowledgments of user traffic and control traffic sent from the RAN to UE 7000 over downlink channels (e.g., the Physical Downlink Shared Channel (PDSCH) and the Physical Dedicated Control Channel (PDCCH)).

The receiving module 7020 may receive information sent by the RAN on downlink channels (e.g., the physical downlink shared channel (PDSCH) and the physical downlink control channel (PDCCH)) and notify the response module 7030 of the reception status of that information. For example, the received subframe may be decoded at the receiving module (and any FEC correction may also be performed here), and an indication of whether the subframe should be ACKed, NACKed, or DTXed may be sent to the response module 7030. The receiving module 7020 may also pass various communication parameters (e.g., the size of the bundling window and the last received DAI for that window) to the response module 7030.

The response module 7030 may notify the transmission module 7010 of appropriate response parameters (e.g., PUCCH resources, RM code bits, constellation) based on the LDAI, the bundling window size, and the like, according to the tables in FIG. 1 and FIG. 2 (continued from FIG. 2A ). For example, the response module 7030 may determine that the number of received downlink assignments is less than the response bundling window size and, based on that determination, set the reception status of each received downlink assignment based on whether the frame associated with the particular received downlink assignment was successfully received and set the reception status of frames in the bundling window without a corresponding downlink assignment to a predetermined value. For example, if one or more received downlink assignment index (DAI) values are equal to j + p , the response module may determine each index j for a plurality of downlink subframes in the response bundling window. In response to determining that one of the one or more DAI values is equal to j + p , the reception status (ACK/NACK/DTX) of the subframe corresponding to j is determined. In response to determining that none of the one or more DAI values is equal to j + p , the reception state of the subframe corresponding to j is set to a predetermined value. Where p is a constant (e.g., 0 or 1), where the one or more DAI values are received on a physical downlink control channel (PDCCH), where j ≤ M -1, and where M is the number of subframes in the HARQ bundling window. The response module 7030 may also be referred to as a HARQ module and may then instruct the transmission module 7010 to transmit an appropriately determined response. In some examples, if a physical downlink shared channel (PDSCH) transmission occurs on the primary cell without a corresponding PDCCH detected within the bundling window, the variable p may be equal to zero; otherwise, p may be one. Thus, the value p may indicate whether a semi-persistent scheduling (SPS) PDSCH without a corresponding PDCCH is present within the bundling window. Note that although the specification describes the PDCCH using a DAI value for a scheduled downlink frame, the present disclosure can also be used when the UE receives a PDCCH indicating a downlink semi-persistent scheduling (SPS) release message, which also includes a DAI value.

Figure 7 also shows a partial functional diagram of an eNodeB 7100 (which may include further components not shown). The eNodeB 7100 includes a transmit module 7110, which transmits user data and control data on one or more channels. For example, user data or control data may be transmitted on the Physical Dedicated Control Channel (PDCCH) or the Physical Dedicated Shared Channel (PDSCH). The transmit module 7110 schedules frames for transmission and signals this to the UE on the PDCCH. The transmit module 7110 may also transmit the DAI on the PDCCH. The receive module 7120 may receive control and user data on uplink communication channels, such as the Physical Uplink Control Channel (PUCCH) and the Physical Uplink Shared Channel (PUSCH). The receive module 7120 may receive HARQ responses (e.g., ACK-NACK-DTX responses) for downlink subframes from the UE. In response to this information, the receive module may indicate to the transmit module that certain data may need to be retransmitted. The receiving module 7120 may decode the response based on determining on which PUCCH resource the response was received, the received satellite position, and the received RM code. The receiving module 7120 may also determine that the last DAI value in the bundling window is less than the number of subframes in the bundling window and that one or more of the ACK/NACK/DTX for the subframe should be ignored because it does not represent an actual transmission.

FIG8 illustrates a block diagram of an example machine 8000, upon which any one or more of the techniques discussed herein (e.g., methodologies) may be performed. A UE, a RAN (including an eNodeB), or an EPC may be machine 8000 or may comprise part of machine 8000. In alternative embodiments, machine 8000 may operate as a standalone device or may be connected (e.g., networked) to other machines. In a networked deployment, machine 8000 may operate as a server machine, a client machine, or in the capacity of both a server-client network environment. In an example, machine 8000 may function as a peer machine in a peer-to-peer (P2P) (or other distributed) network environment. Machine 8000 may be a personal computer (PC), a tablet PC, a set-top box (STB), a personal digital assistant (PDA), a mobile phone (e.g., a UE), a network appliance, a wireless base station, a network router, a switch, or a bridge, or any machine capable of executing (continuously or otherwise) instructions that specify actions to be taken by that machine. Further, while a single machine is illustrated, the term "machine" shall also be taken to include any collection of machines that individually or jointly execute a set (or multiple sets) of instructions to perform any one or more of the methodologies discussed herein, e.g., cloud computing, software as a service (SaaS), or other computer cluster configurations. For example, the functionality of Machine 8000 may be distributed across multiple other machines in a network.

Examples as described herein may include or may operate on a logic or multiple components, modules, or mechanisms. A module is a tangible entity that is capable of performing a specific operation and may be configured or arranged in a certain manner. In an example, circuits may be arranged in a specified manner (e.g., internally or with respect to external entities (e.g., other circuits)) as a module. In an example, all or part of one or more computer systems (e.g., standalone client or server computer systems) or one or more hardware processors may be configured by firmware or software (e.g., instructions, application components, or applications) to operate as a module that performs specified operations. In an example, the software may reside on (1) a non-transitory machine-readable medium or (2) a transmission signal. In an example, when executed by the underlying hardware of the module, the software causes the hardware to perform the specified operations.

Thus, the term "module" is understood to encompass a tangible entity that is physically constructed, specifically configured (e.g., hardwired), or temporarily (e.g., provisionally) configured (e.g., programmed) to operate in a prescribed manner or to perform some or all of any of the operations described herein. Considering examples where modules are temporarily configured, it is not necessary to instantiate each module at any one time. For example, where a module comprises a general-purpose hardware processor configured using software, the general-purpose hardware processor can be configured into one or more modules that can change over time. For example, software can thus configure a hardware processor to constitute a particular module at one instance in time and to constitute a different module at a different instance in time.

A machine (e.g., a computer system) 8000 may include a hardware processor 8002 (e.g., a central processing unit (CPU), a graphics processing unit (GPU), a hardware processor core, or any combination thereof), a main memory 8004, and a static memory 8006, some or all of which may communicate with each other via a bus 8008. The machine 8000 may also include a display unit 8010, an alphanumeric input device 8012 (e.g., a keyboard), a user interface (UI) control device 8014, and/or other input devices. In an example, the display unit 8010 and the UI control device 8014 may be a touch screen display. The machine 8000 may also include a storage device (e.g., a drive unit) 8016, a signal generating device 8018 (e.g., a speaker), and a network interface device 8020.

The storage device 8016 may include a machine-readable medium 8022 on which is stored one or more sets of data structures or instructions 8024 (e.g., software) that implement or are utilized by any one or more of the techniques or functionality described herein. During execution thereof by the machine 8000, the instructions 8024 may also reside (completely or at least partially) within the main memory 8004, within the static storage 8006, or within the hardware processor 8002. In an example, one or any combination of the hardware processor 8002, the main memory 8004, the static storage 8006, or the storage device 8016 may constitute a machine-readable medium.

Although the machine-readable medium 8022 is illustrated as a single medium, the term “machine-readable medium” may encompass a single medium or multiple media (eg, a centralized or distributed database, and/or associated caches and servers) configured to store one or more instructions 8024 .

The term "machine-readable medium" may include any tangible medium that can store, encode, or carry instructions for execution by the machine 8000 and that causes the machine 8000 to perform any one or more of the techniques disclosed herein, or that can store, encode, or carry data structures used by or associated with such instructions. Non-limiting examples of machine-readable media include solid-state memory and optical and magnetic media. Specific examples of machine-readable media include non-volatile memory such as semiconductor memory devices (e.g., electrically programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM)) and flash memory devices; magnetic disks such as internal hard disks and removable disks; magneto-optical disks; and CD-ROM and DVD-ROM disks.

Instructions 8024 may also be transmitted or received over a communication network 8026 using a transmission medium via the network interface device 8020. The network interface device 8020 may connect the machine 8000 to a network of other machines to communicate with the other machines in the network by utilizing any of a number of transmission protocols (e.g., frame relay, Internet Protocol (IP), transmission control protocol (TCP), user datagram protocol (UDP), hypertext transfer protocol (HTTP), etc.). Example communication networks may include a local area network (LAN), a wide area network (WAN), a packet data network (e.g., the Internet), a mobile phone network (e.g., a cellular network), a plain old telephone (POTS) network, and a wireless data network (e.g., the Institute of Electrical and Electronics Engineers (IEEE) 802.11 family of standards known as Wi-Fi®, the IEEE 802.16 family of standards known as WiMax®), a peer-to-peer (P2P) network, and others. In an example, the network interface device 8020 may include one or more physical jacks (e.g., Ethernet, coaxial, or telephone jacks) or one or more antennas to connect to the communication network 8026. In an example, and as shown in FIG8 , the network interface device 8020 may include multiple antennas (not shown) to communicate wirelessly using at least one of single-input multiple-output (SIMO), multiple-input multiple-output (MIMO), or multiple-input single-output (MISO) technology. The term "transmission medium" shall be construed to include any intangible medium capable of storing, encoding, or carrying instructions for execution by the machine 8000, including digital or analog communication signals or other intangible media to facilitate communication of such software.

Additional Notes and Examples

Example 1: Disclosed is a user equipment (UE) comprising: a response module arranged to receive one or more downlink assignments of a beaming window on a wireless downlink control channel; setting a reception status of each subframe of the downlink data channel in the beaming window based on whether the subframe on the downlink data channel is associated with a specific assignment in the downlink assignment and based on whether the subframe is successfully received, and setting the reception status of a subframe of the downlink data channel in the beaming window that does not have a corresponding downlink assignment to a predetermined value; and a transmission module arranged to transmit a response, the response being based on the reception status set by the response module.

Example 2: The UE of Example 1, wherein the reception state is one of acknowledgement (ACK), negative acknowledgement (NACK), and discontinuous reception (DTX).

Example 3: The UE of any of Examples 1-2, wherein the predetermined value is a value indicating discontinuous transmission (DTX).

Example 4: The UE of any of Examples 1-3, wherein the UE is arranged to operate in a time division duplex (TDD) mode and wherein the transmitting module is arranged to transmit the response using a physical uplink control channel (PUCCH) format 1b.

Example 5: The UE of any of Examples 1-4, wherein the bundling window is greater than 2 subframes.

Example 6: The UE of any of Examples 1-5, wherein the transmitting module is arranged to transmit the response by selecting a PUCCH uplink resource, a constellation, and a set of code input bits based on a reception status.

Example 7: The UE of any of Examples 1-6, wherein the UE is arranged to communicate with the wireless network using the Long Term Evolution (LTE) family of standards.

Example 8: The UE of any of Examples 1-7, wherein the UE is arranged to utilize carrier aggregation with a two serving cell configuration.

Example 9: Disclosed is a method comprising determining, for each index j for a plurality of downlink subframes, whether one or more received downlink assignment index (DAI) values are equal to j+p, the one or more DAI values being received on a physical downlink control channel (PDCCH), where j ≤ M -1, M is the number of subframes in a HARQ bundling window, and p is a constant; in response to determining that none of the one or more DAI values are equal to j+1, setting a reception status of the subframe corresponding to j to a predetermined value; and transmitting a reception status for each of the plurality of downlink subframes j in the bundling window M.

Example 10: The method of Example 9, wherein the predetermined value is a value indicating discontinuous transmission (DTX).

Example 11: The method of any of Examples 9-10, comprising: determining whether there is a primary downlink shared channel (PDSCH) transmission on the primary cell that does not have a corresponding PDCCH detected within the beamforming window; in response to determining that there is a PDSCH without a corresponding PDCCH, setting p to 0; in response to determining that there is no PDSCH without a corresponding PDCCH, setting p to 1.

Example 12: The method of any of Examples 9-11, wherein the reception status is transmitted using Physical Uplink Control Channel (PUCCH) format 1b.

Example 13: The method of any of Examples 9-12, comprising transmitting the reception status by selecting at least a PUCCH uplink resource, a constellation, and a set of code input bits based on the reception status.

Example 14: Disclosed is a user equipment (UE) comprising: a hybrid automatic repeat request (HARQ) module arranged to: for each index j for a plurality of downlink subframes: determine whether one or more received downlink assignment index (DAI) values are equal to j + p, where p is a constant, the one or more DAI values are received on a physical downlink control channel (PDCCH), where j ≤ M –1, and where M is the number of subframes in a HARQ bundling window, in response to determining that one of the one or more DAI values is equal to j + p, determine a reception state corresponding to the subframe j, and in response to determining that none of the one or more DAI values is equal to j + p, set the reception state corresponding to the subframe j to a predetermined value; and a transmission module arranged to transmit the reception state of each of the plurality of downlink subframes j in the bundling window M.

Example 15: The UE of Example 14, wherein the reception state is one of acknowledgement (ACK), negative acknowledgement (NACK), and discontinuous reception (DTX).

Example 16: The UE of any of Examples 14-15, wherein the predetermined value is a value indicating discontinuous transmission (DTX).

Example 17: The UE of any of Examples 14-16, wherein the predetermined value is different from a value indicating ACK, NACK, and DTX.

Example 18: The UE of any of Examples 14-17, wherein the predetermined value is a value randomly selected from one of values indicating ACK, NACK, and DTX.

Example 19: The UE of any of Examples 14-18, wherein the UE is arranged to operate in a time division duplex (TDD) mode.

Example 20: The UE of any of Examples 14-19, wherein the UE is arranged to multiplex HARQ reception states.

Example 21: The UE of any of Examples 14-20, wherein the transmitting module is arranged to transmit the reception status using a physical uplink control channel (PUCCH) format 1b.

Example 22: The UE of any of Examples 14-21, wherein the HARQ module is further arranged to: determine whether there is a primary downlink shared channel (PDSCH) transmission on the primary cell without a corresponding PDCCH detected within the beamforming window; in response to determining that there is a PDSCH without a corresponding PDCCH, set p to 0; in response to determining that there is no PDSCH without a corresponding PDCCH, set p to 1.

Example 23: The UE of any one of Examples 14-22, wherein the transmitting module is arranged to transmit the reception status by selecting a PUCCH uplink resource, a constellation, and a set of code input bits based on the reception status.

Example 24: The UE of any of Examples 14-23, wherein the UE is arranged to communicate with the wireless network using the Long Term Evolution (LTE) family of standards.

Claims (3)

1. A computer-readable medium comprising instructions that, when executed on a device, cause the device to: Receive one or more downlink assignment index (DAI) values within a bundled window, the DAI values being received on the physical downlink control channel (PDCCH); It is determined that none of the DAI values are equal to j+p, where j is the HARQ acknowledgment response index and p is a constant; In response to the determination, the HARQ receive state corresponding to j is set to discontinuous transmission (DTX); and The HARQ receive status is transmitted using Physical Uplink Control Channel (PUCCH) format 1b. 2. The computer-readable medium of claim 1, further comprising instructions that, when executed on the device, cause the device to: Determine whether there is a downlink shared channel transmission on the main cell that does not have a corresponding downlink control channel detected within the bundled window; In response to determining that a downlink shared channel without a corresponding downlink control channel exists on the primary cell, p is set to 0; and In response to determining that there is no downlink shared channel without a corresponding downlink control channel on the primary cell, p is set to 1. 3. The computer-readable medium of claim 1, further comprising instructions that, when executed on the device, cause the device to: In response to the determination that a downlink shared channel transmission with the corresponding control channel transmission on the primary cell exists on the secondary cell, p is set to 1.