RU2840329C2 - Method and equipment for fault-tolerant reception of transmission of messages over direct transit network - Google Patents

Abstract

FIELD: wireless communication.

SUBSTANCE: method comprises steps of transmitting, to an O-RAN (O-RU) radio unit via a direct transit interface, one or more control plane (C-plane) messages and receiving, from the O-RU via a direct transit interface, an acknowledgment (ACK)/non-acknowledgment (NACK) feedback message for the one or more C-plane messages, wherein each C-plane message from said one or more C-plane messages includes section extension information for requesting ACK/NACK, wherein the section extension information includes a request identifier (ID) used to identify a section description for which ACK/NACK feedback is requested, and wherein the ACK/NACK feedback message includes at least one of ACK information for indicating a request identifier of a correctly decoded section description or NACK information for indicating a request identifier for an incorrectly decoded section description.

EFFECT: providing fault-tolerant transmission and reception of messages over a direct transit network.

16 cl, 12 dwg, 2 tbl

Description

Field of technology to which the invention relates

[1] This disclosure relates generally to communication systems, and more specifically, this disclosure relates to robust (fault-tolerant) transmission and reception of messages over a forward transit network.

State of the art

[2] Fifth generation (5G) or new radio (NR) mobile communications has recently gained increasing momentum due to all the global technical activities for various possible technology options in industry and science. In the current open radio access network (O-RAN) based forward backhaul network, robustness of the core network is required, and several techniques are provided for the sending device to detect the failure of the forward backhaul message or the failure of the decoding of the message at the receiving device.

The essence of the invention

Solution to the problem

[3] The present disclosure relates to communication systems, and more particularly, the present disclosure relates to fault-tolerant transmission and reception of messages over a direct transit network.

[4] In one embodiment, a base station transmitter is provided for processing an acknowledgement of a control plane (C-plane) message in a wireless communication system. The DU comprises a processor configured to generate a section extension for an acknowledgement/denial of receipt (ACK/NACK) request that includes an ACK/NACK request identifier field (ackNackReqId) and a length field (extLen), wherein the ackNackReqId field indicates an identifier (ID) of the ACK/NACK request of a description of the sections, and the extLen field indicates a size of the section extension. The transmitter further comprises a transceiver operatively connected to the processor, wherein the transceiver is configured to: transmit, to a receiver, a C-plane message that includes the section extension for the ACK/NACK request, and receive, from the RU, an ACK message corresponding to the C-plane message.

[5] In another embodiment, a receiving device is provided for processing an acknowledgment of a C-plane message in a wireless communication system. The receiving device comprises a transceiver configured to receive, from a transmitting device, a C-plane message including a section extension for an ACK/NACK request. The receiving device further comprises a processor operatively connected to the transceiver, wherein the processor is configured to identify a section extension included in the C-plane message for the ACK/NACK request including an ackNackReqId field and an extLen field, wherein the ackNackReqId field indicates an identifier of the ACK/NACK request of the section description, and the extLen field indicates a size of the section extension. The transceiver of the receiving device is further configured to transmit, to the transmitting device, an ACK message corresponding to the C-plane message.

[6] In yet another embodiment, a method is provided for a base station transmitter for processing an acknowledgment of a C-plane message in a wireless communication system. The transmitter comprises: generating a section extension for an ACK/NACK request that includes an ackNackReqId field and an extLen field, wherein the ackNackReqId field indicates an identifier of an ACK/NACK request of a section description, and the extLen field indicates a size of the section extension; transmitting, to a receiver, a C-plane message that includes the section extension for the ACK/NACK request; and receiving, from the receiver, an ACK message corresponding to the C-plane message.

[7] According to embodiments, a method is performed by an open radio access network (O-RAN) distributed unit (O-DU). The method comprises transmitting, to an O-RAN radio unit (O-RU) via a forward backhaul interface, one or more control plane (C-plane) messages. The method comprises receiving, from the O-RU via the forward backhaul interface, an acknowledgement (ACK)/denial of acceptance (NACK) feedback message for the one or more C-plane messages. Each C-plane message of the one or more C-plane messages includes section extension information for an ACK/NACK request. The section extension information includes a request identifier (ID) used to identify a section description for which ACK/NACK feedback is requested. The ACK/NACK feedback message includes at least one of ACK information for indicating a request identifier of a correctly decoded section description or NACK information for indicating a request identifier of an incorrectly decoded section description.

[8] According to embodiments, a method is performed by an open radio access network (O-RAN) radio unit (O-RU). The method comprises receiving, from a distributed O-RAN unit (O-DU) via a forward backhaul interface, one or more control plane (C-plane) messages. The method comprises transmitting, to the O-RU via the forward backhaul interface, an acknowledgement (ACK)/denial of acceptance (NACK) feedback message for the one or more C-plane messages. Each C-plane message of the one or more C-plane messages includes section extension information for an ACK/NACK request. The section extension information includes a request identifier used to identify a section description for which ACK/NACK feedback is requested. The ACK/NACK feedback message includes at least one of ACK information for indicating a request identifier of a correctly decoded section description or NACK information for indicating a request identifier of an incorrectly decoded section description.

[9] According to embodiments, an open radio access network (O-RAN) distributed unit (O-DU) device comprises at least one transceiver and at least one processor coupled to the at least one transceiver. The at least one processor is configured to control the at least one transceiver to transmit, to an O-RAN radio unit (O-RU) via a forward backhaul interface, one or more control plane (C-plane) messages. The at least one processor is configured to control the at least one transceiver to receive, from the O-RU via a forward backhaul interface, an acknowledgement (ACK)/negation (NACK) feedback message for the one or more C-plane messages. Each C-plane message of the one or more C-plane messages includes section extension information for an ACK/NACK request. The section extension information includes a request identifier used to identify a section description for which ACK/NACK feedback is requested. The ACK/NACK feedback message includes at least one of ACK information to indicate a request identifier of a correctly decoded section description or NACK information to indicate a request identifier of an incorrectly decoded section description.

[10] According to embodiments, an open radio access network (O-RAN) radio unit (O-RU) device for the method comprises at least one transceiver and at least one processor coupled to the at least one transceiver. The at least one processor is configured to control the at least one transceiver to receive, from an O-RAN distributed unit (O-DU) via a forward backhaul interface, one or more control plane (C-plane) messages. The at least one processor is configured to control the at least one transceiver to transmit, to the O-RU via a forward backhaul interface, an acknowledgement (ACK)/negation (NACK) feedback message for the one or more C-plane messages. Each C-plane message of the one or more C-plane messages includes section extension information for an ACK/NACK request. The section extension information includes a request identifier used to identify a section description for which ACK/NACK feedback is requested. The ACK/NACK feedback message includes at least one of ACK information to indicate a request identifier of a correctly decoded section description or NACK information to indicate a request identifier of an incorrectly decoded section description.

[11] Other technical features may be readily apparent to those skilled in the art from the following drawings, descriptions and claims.

[12] Before proceeding to the Detailed Description of the Invention section below, it may be advantageous to set forth definitions of certain words and phrases used in this patent document. The term "connect" and its derivatives mean any direct or indirect connection between two or more elements, whether or not those elements are in physical contact with each other. The terms "transmit," "receive," and "communicate," and their derivatives, cover both direct and indirect connections. The terms "include" and "contain," and their derivatives, mean inclusion without limitation. The term "or" is inclusive, meaning both and/or. The phrase "associated with" and its derivatives mean to include, be included in, be interconnected with, contain, be contained in, connect with, couple to, communicate with, interact with, intersperse, be located adjacent to, be adjacent to, be bound to or with, have, have the property of, have a relationship, and the like. The term "controller" means any device, system, or portion thereof that controls at least one operation. Such a controller may be implemented in hardware or in a combination of hardware and software and/or firmware. The functionality associated with any particular controller may be centralized or distributed, local or remote. The phrase "at least one of," when used with a list of items, means that various combinations of one or more of the listed items may be used, and only one item in the list may be required. For example, "at least one of the following: A, B, and C" includes any of the following combinations: A, B, C, A and B, A and C, B and C, and A and B, and C.

[13] In addition, the various functions described below may be implemented or supported by one or more computer programs, each of which is formed from machine-readable program code and embodied in a machine-readable medium. The terms "application" and "program" mean one or more computer programs, program components, sets of instructions, procedures, functions, objects, classes, instances, associated data, or portions thereof, adapted to be embodied in suitable machine-readable program code. The phrase "machine-readable program code" includes any type of machine code, including source code, object code, and executable code. The phrase "machine-readable medium" includes any type of medium capable of being accessed by a computer, such as read-only memory (ROM), random access memory (RAM), hard disk, compact disc (CD), digital video disc (DVD), or any other type of storage device. A "non-volatile" computer-readable medium excludes wired, wireless, optical, or other communication links that transport transient electrical or other signals. Non-volatile computer-readable media includes media on which data can be permanently stored and media on which data can be stored and subsequently rewritten, such as a rewritable optical disc or erasable memory device.

[14] Definitions for certain other words and phrases are provided throughout this patent document. Those skilled in the art will appreciate that in many, if not most, instances, such definitions apply to prior as well as future uses of such certain words and phrases.

Brief description of the drawings

[15] For a more complete understanding of the present invention and its advantages, reference should now be made to the following description taken in conjunction with the accompanying drawings, in which like reference numerals represent like parts:

[16] Fig. 1 illustrates an example of a communication system according to embodiments of the present disclosure;

[17] Fig. 2 illustrates an example of a network entity according to embodiments of the present disclosure;

[18] Fig. 3 illustrates an example of a client device according to embodiments of the present disclosure;

[19] Fig. 4 illustrates an example of a base station according to embodiments of the present disclosure;

[20] Fig. 5 illustrates an example of a high-level message sequence according to embodiments of the present disclosure;

[21] Fig. 6 illustrates an example of a message sequence for robust message transmission and reception according to an embodiment of the present disclosure;

[22] Fig. 7 illustrates another example of a message sequence for fault-tolerant message transmission and reception according to an embodiment of the present disclosure;

[23] Fig. 8 illustrates an example of a message format according to embodiments of the present disclosure;

[24] Fig. 9 illustrates another example of a message format according to embodiments of the present disclosure;

[25] Fig. 10 illustrates a flow chart of a method for fault-tolerant transmission and reception of messages over a forward transit network according to embodiments of the present disclosure;

[26] Fig. 11 illustrates a flow chart of a method for fault-tolerant transmission and reception of messages over a forward transit network according to embodiments of the present disclosure; and

[27] Fig. 12 illustrates an example of a direct transit interface according to embodiments of the present disclosure.

Mode of implementation of the invention

[28] Figs. 1-12, described below, and the various embodiments used to describe the principles of the present invention in this patent document are provided for illustrative purposes only and should not be construed as limiting the scope of the disclosure in any way. Those skilled in the art will appreciate that the principles of this disclosure may be implemented in any suitably configured device or system.

[29] Fig. 1 illustrates an exemplary communication system 100 according to this disclosure. The embodiment of the communication system 100 shown in Fig. 1 serves for illustration only. Other embodiments of the communication system 100 may be used without departing from the scope of this disclosure.

[30] As shown in Fig. 1, system 100 includes network 102 that facilitates communication between various components in system 100. For example, network 102 may communicate packets over Internet Protocol (IP), frames over Frame Relay Protocol, cells over Asynchronous Transfer Mode (ATM) protocol, or other information between network addresses. Network 102 may include one or more local area networks (LANs), metropolitan area networks (MANs), wide area networks (WANs), all or part of a global network such as the Internet, or any other communication system or systems in one or more locations.

[31] Network 102 facilitates communication between at least one server 104 and various client devices 106-114, such as a user equipment (UE), a terminal, or any device including communication capabilities. Each server 104 includes any suitable computing or processing device that can provide computing services for one or more client devices. Each server 104, for example, may include one or more processing devices, one or more memory devices storing instructions and data, and one or more network interfaces facilitating communication over network 102.

[32] Each client device 106-114 represents any suitable communication device or processing device that interacts with at least one server or other communication device(s) over network 102. In this example, client devices 106-114 include a desktop computer 106, a mobile phone or smartphone 108, a personal digital assistant 110 (PDA), a laptop computer 112, and a tablet computer 114. However, any other or additional client devices may be used in communication system 100.

[33] In this example, some client devices 108-114 communicate indirectly with network 102. For example, client devices 108-110 communicate through one or more base stations 116, such as cellular base stations or enhanced Node Bs. In addition, client devices 112-114 communicate through one or more wireless access points 118, such as IEEE 802.11 wireless access points. It should be noted that these are for illustration purposes only, and that each client device can communicate directly with network 102 or indirectly with network 102 through any suitable intermediate device(s) or network(s).

[34] Although FIG. 1 illustrates one example of a communication system 100, various changes may be made to FIG. 1. For example, system 100 may include any number of each of the components in any suitable arrangement. In general, computing systems and communication systems come in a wide variety of configurations, and FIG. 1 does not limit the scope of this disclosure to any particular configuration. Although FIG. 1 illustrates one operating environment in which various features disclosed in this patent document may be used, these features may be used in any other suitable system.

[35] Fig. 2 and 3 illustrate exemplary devices in a communication system according to this disclosure. In particular, Fig. 2 illustrates an exemplary server 200, and Fig. 3 illustrates an exemplary client device 300. Server 200 may represent server 104 in Fig. 1, and client device 300 may represent one or more client devices 106-114 in Fig. 1.

[36] As shown in Fig. 2, the server 200 includes a bus system 205 that supports communication between at least one processor 210, at least one data storage device 215, at least one communication circuit 220, and at least one input/output unit 225.

[37] The processor 210 executes instructions that may be loaded into the memory 230. The processor 210 may include any suitable number(s) and type(s) of processors or other devices in any suitable arrangement. Exemplary types of the processor 210 include microprocessors, microcontrollers, digital signal processors, field programmable gate arrays, application-specific integrated circuits, and discrete circuitry. The processor 210 is also capable of executing other processes and programs resident in the memory 230, such as processes for robust transmission and reception of messages over a forward backhaul network in a wireless communication system.

[38] The storage device 230 and the persistent storage device 235 are examples of data storage devices 215 that represent any structure(s) that are capable of storing and facilitating retrieval of information (such as data, program code, and/or other suitable information on a temporary or permanent basis). The storage device 230 may represent a random access memory device or any other suitable volatile or nonvolatile data storage device(s). The persistent storage device 235 may comprise one or more components or devices that support long-term data storage, such as a read-only memory, a hard drive, a flash memory, or an optical disk.

[39] The communication circuit 220 supports communication with other systems or devices. For example, the communication circuit 220 may include a network interface card or a wireless transceiver that facilitates communication over the network 102. The communication circuit 220 may support communication via any suitable physical or wireless communication line(s).

[40] The input/output circuit 225 provides the ability to input and output data. For example, the input/output circuit 225 may provide a connection for user input via a keyboard, mouse, keypad, touch screen, or other suitable input device. The input/output circuit 225 may also send output to a display, printer, or other suitable output device.

[41] The processor 210 is also coupled to a display 240. The display 240 may be a liquid crystal display or other display capable of rendering text and/or at least limited graphics, such as from web sites.

[42] It should be noted that, although Fig. 2 is described as representing the server 104 of Fig. 1, the same or similar structure may be used in one or more client devices 106-114. For example, a laptop or desktop computer may have a structure the same or similar to the structure shown in Fig. 2.

[43] Fig. 3 illustrates an exemplary client device 116 according to embodiments of the present disclosure. The embodiment of the client device 116 illustrated in Fig. 3 serves for illustration only, and the client devices 106-114 of Fig. 1 may have the same or similar configuration. However, client devices are available in a wide variety of configurations, and Fig. 3 does not limit the scope of this disclosure to any particular implementation of a client device.

[44] As shown in Fig. 3, client devices 106-114 may include an antenna 305, a radio frequency (RF) transceiver 310, a Tx processing circuit 315, a microphone 320, and an Rx processing circuit 325. Client device 104-116 also includes a speaker 330, a processor 340, an input/output interface 345, a touch screen 350, a display 355, and a memory device 360. Memory device 360 includes an operating system 361 (OS) and one or more applications 362.

[45] The RF transceiver 310 receives, from the antenna 305, an incoming RF signal transmitted by a network entity (e.g., a gNB, BS, eNB) of the network 100. The RF transceiver 310 down-converts the incoming RF signal to generate an intermediate frequency (IF) signal or a baseband signal. The IF signal or baseband signal is sent to the Rx processing circuit 325, which generates a processed baseband signal by filtering, decoding and/or digitizing the baseband signal or IF signal. The Rx processing circuit 325 transmits the processed baseband signal to the speaker 330 (e.g., for voice data) or to the processor 340 for further processing (e.g., for web browsing data).

[46] The Tx processing circuit 315 receives analog or digital voice data from the microphone 320 or other outgoing baseband data (e.g., web data, e-mail data, or interactive video game data) from the processor 340. The Tx processing circuit 315 encodes, multiplexes, and/or digitizes the outgoing baseband data to generate a processed baseband signal, or IF signal. The RF transceiver 310 receives the outgoing processed baseband signal, or IF signal, from the Tx processing circuit 315 and upconverts the baseband signal, or IF signal, into an RF signal, which is transmitted via the antenna 305.

[47] The processor 340 may include one or more processors or other processing devices and execute the OS 361 stored in the memory device 360 to completely control the operation of the client devices 106-114. For example, the processor 340 may control the reception of the DL channel signals and the transmission of the UL channel signals by means of the RF transceiver 310, the Rx processing circuit 325 and the Tx processing circuit 315 in accordance with known principles. In some embodiments, the processor 340 includes at least one microprocessor or microcontroller.

[48] The processor 340 is also capable of executing other processes and programs resident in the memory 360, such as processes for fault-tolerant transmission and reception of messages over a direct backhaul network in a wireless communication system. The processor 340 can move data to or from the memory 360 as needed via an executing process. In some embodiments, the processor 340 is configured to execute applications 362 based on the OS 361 or in response to signals received from the gNB or from an operator. The processor 340 is also connected to an input/output interface 345 that provides the client device 106-114 with the ability to connect to other devices, such as laptops and handheld computers. The input/output interface 345 is a communication path between these auxiliary devices and the processor 340.

[49] The processor 340 is also connected to a touch screen 350 and a display 355. An operator of the client device 106-114 may use the touch screen 350 to enter data into the client device 106-114. The display 355 may be a liquid crystal display, a light emitting diode display, or another display capable of rendering text and/or at least limited graphics, such as from websites.

[50] Memory 360 is coupled to processor 340. A portion of memory 360 may include random access memory (RAM), and another portion of memory 360 may include flash memory or other read-only memory (ROM).

[51] Although Fig. 3 illustrates one example of a client device 106-114, various changes can be made to Fig. 3. For example, various components in Fig. 3 can be combined, further subdivided, or omitted, and additional components can be added according to specific needs. As a specific example, the processor 340 can be divided into multiple processors, such as one or more central processing units (CPUs) and one or more graphic processing units (GPUs). In addition, although Fig. 3 illustrates a client device configured as a mobile phone or smartphone, UEs can be configured to operate as other types of mobile or stationary devices.

[52] FIG. 4 illustrates an example base station (e.g., 116 and 118) according to embodiments of the present disclosure. The embodiment of base station 400 illustrated in FIG. 4 serves for illustration only, and base stations 116 and 118 of FIG. 1 may have the same or similar configuration. However, base stations are produced in a wide variety of configurations, and FIG. 2 does not limit the scope of this disclosure to any particular implementation of a base station.

[53] As shown in Fig. 2, the base station 400 includes a plurality of antennas 405a-405n, a plurality of RF transceivers 410a-410n, a transmit (Tx) processing circuit 415, and a receive (Rx) processing circuit 420. The base station 400 also includes a controller/processor 425, a memory 430, and a reverse transit or network interface 435.

[54] RF transceivers 410a-410n receive, from antennas 405a-405n, incoming RF signals, such as signals transmitted by client devices, such as UEs in network 100. RF transceivers 410a-410n downconvert the incoming RF signals to generate IF signals or baseband signals. The IF signals or baseband signals are sent to Rx processing circuit 420, which generates processed baseband signals by filtering, decoding and/or digitizing the baseband signals or IF signals. Rx processing circuit 420 transmits the processed baseband signals to controller/processor 425 for further processing.

[55] The Tx processing circuit 415 receives analog or digital data (e.g., voice data, web data, e-mail data, or interactive video game data) from the controller/processor 425. The Tx processing circuit 415 encodes, multiplexes, and/or digitizes the outgoing baseband data to generate processed baseband signals, or IF signals. The RF transceivers 410a-410n receive the outgoing processed baseband signals, or IF signals, from the Tx processing circuit 415 and upconvert the baseband signals, or IF signals, into RF signals that are transmitted via the antennas 405a-405n.

[56] The controller/processor 425 may include one or more processors or other processing devices that completely control the operation of the base station 400. For example, the controller/processor 425 may control the reception of forward channel signals and the transmission of reverse channel signals via the RF transceivers 410a-410n, the Rx processing circuit 420 and the Tx processing circuit 415 in accordance with known principles. The controller/processor 425 may also support additional functions, such as advanced wireless communication functions. For example, the controller/processor 425 may support beamforming or directional routing operations in which outgoing/incoming signals from/to multiple antennas 405a-405n are weighted differently in order to effectively steer the outgoing signals in a desired direction. Any wide range of other functions may be supported in the base station 400 by the controller/processor 425.

[57] The controller/processor 225 also allows execution of programs and other processes residing in the memory device 430, such as an OS. The controller/processor 425 can move data to or from the memory device 430 as needed by an executing process.

[58] Controller/processor 425 is also coupled to reverse backhaul or network interface 435. Reverse backhaul or network interface 435 enables base station 400 to communicate with other devices or systems over a reverse backhaul connection or over a network. Interface 435 may support communication over any suitable wired or wireless connection(s). For example, when base station 400 is implemented as part of a cellular communication system (e.g., a system supporting 5G/NR, LTE, or LTE-A), interface 435 may enable base station 400 to communicate with other gNBs over a wired or wireless reverse backhaul connection. When base station 400 is implemented as an access point, interface 435 may enable base station 400 to communicate over a wired or wireless local area network or over a wired or wireless connection to a larger network (such as the Internet). The 435 interface includes any suitable structure that supports wired or wireless communication, such as an Ethernet or RF transceiver.

[59] Memory 430 is coupled to controller/processor 425. A portion of memory 430 may include RAM, and another portion of memory 430 may include flash memory or other ROM.

[60] Although FIG. 4 illustrates one example of base station 400, various changes may be made to FIG. 4. For example, base station 400 may include any number of each of the components shown in FIG. 4. As a specific example, an access point may include a number of interfaces 435, and a controller/processor 425 may support fault-tolerant transmission and reception of messages over a forward backhaul network. As another specific example, although shown as including a separate instance of Tx processing circuitry 415 and a separate instance of Rx processing circuitry 420, base station 400 may include multiple instances of each (e.g., one per RF transceiver). Furthermore, the various components in FIG. 4 may be combined, further subdivided, or omitted, and additional components may be added according to specific needs.

[61] Although Fig. 2, 3 and 5 illustrate examples of devices in a communication system, various changes can be made to Fig. 2, 3 and 4. For example, various components in Fig. 2, 3 and 4 can be combined, further subdivided or omitted, and additional components can be added according to specific needs. As a specific example, the main processor 340 can be divided into multiple processors, such as one or more central processing units (CPUs) and one or more graphic processing units (GPUs). In addition, although Fig. 3 illustrates a client device 300 configured as a mobile phone or smartphone, client devices can be configured to operate as other types of mobile or stationary devices. In addition, similar to computing and communication networks, client devices and servers can be produced in a wide variety of configurations, and Fig. 2, 3 and 4 do not limit this disclosure to any particular client device or server.

[62] In the current O-RAN forward backhaul protocol specification, resilience to core network failures is assumed and there is no way for the sending device to detect a failure in transmitting messages over the forward backhaul network or a failure in decoding messages at the receiving device.

[63] In one example, an open distributed unit (O-DU) (e.g., a baseband unit (BBU)) sends control plane messages to an open radio unit (O-RU) describing how to transmit user plane data over the air interface in the downlink direction, or how to receive air interface data and send it to the O-DU in the uplink.

[64] In one example, if a control plane packet is lost in the forward transit network or incorrectly decoded by the O-RU, the O-RU cannot transmit data in the DL or receive data in the UL.

[65] In one example, this non-radio user data information is not available at the O-DU to perform additional action for a very long period of time (i.e., until a 3GPP Hybrid Automatic Repeat Request (HARQ) or ARQ feedback is received from the UE).

[66] The sender of O-RAN messages over the direct transit interface has no way of knowing whether the messages are being received at the receiving device, and if they are, whether the messages are being decoded correctly at the receiving device. In some cases, the lack of this information may cause interruptions in the transmission and reception of the mobile network.

[67] Embodiments of the present disclosure provide a method for signaling the intent of a sending device (e.g., an O-DU) to receive feedback from a receiving device (e.g., an O-RU) regarding the reception status and decoding status of messages sent by the sending device. In the present disclosure, the term "O-DU" may be replaced by the term "DU" for general descriptions. In addition, the term "O-RU" may be replaced by the term "DU" for general descriptions.

[68] In one embodiment, a new section extension is provided for this purpose. This section extension may be added to the end of existing O-RAN control plane messages.

[69] In one example, upon receiving a section extension indicating a feedback request along with a message, the receiving device (e.g., O-RU) of the message sends the message decoding status to the sending device (e.g., O-DU). The present disclosure provides the creation of a new control plane message type (section type 8) in the O-RAN specification for this purpose.

[70] In one example, a new section extension is provided for a C-plane message to request acknowledgement and decoding status of a C-plane message (e.g., acknowledgement/denial of receipt (ACK/NACK)).

[71] In one example, O-DU appends the provided new C-plane message section extension to request ACK/NACK feedback.

[72] In one example, a new message is provided from the O-RU to the O-DU to indicate the ACK/NACK status of the section descriptions in the C-plane message.

[73] FIG. 5 illustrates an example of a high-level message flow 500 according to embodiments of the present disclosure. The high-level message flow 500 may be implemented by a network entity (e.g., networks 102 and 200, as illustrated in FIG. 2) and/or a client device (e.g., 106-114, as illustrated in FIG. 1). For example, the O-DU 520 may be implemented in one of the network entity in 102, in the server 104, and/or in the base stations 116 and 118. In particular, the base station 116 and 118 may be implemented in a gNB that includes a logical node that hosts a radio link control (RLC) layer/medium access control (MAC) layer/upper physical layer (PHY) based on a functional decomposition at the lower layers. For example, O-RU 530 may be implemented in base stations 116 and 118. In particular, base station 116 and 118 may be implemented in a remote radio head (RRH) or a transmit/receive point (TRP) that includes a logical node that hosts a lower PHY layer and RF processing based on a functional partitioning at lower layers.

[74] The embodiment of the high-level message sequence 500 shown in Fig. 5 is for illustrative purposes only. One or more components illustrated in Fig. 5 may be implemented in a dedicated circuit configured to perform the functions mentioned, or one or more components may be implemented by one or more processors executing instructions to perform the functions mentioned.

[75] As illustrated in FIG. 5, in step 502, the O-DU (520) sends a C-plane message #1 with the ACK/NACK sections extension to the O-RU (530). However, this transmission is discarded and is not sent correctly to the O-RU (530). In step 504, the O-RU (530) sends a C-plane message #2 with the ACK/NACK sections extension to the O-RU (530), and this message is successfully sent to the O-RU. In step 506, the O-RU (530) sends a C-plane message #3 with the ACK/NACK sections extension to the O-RU (530), and this message is successfully sent to the O-RU (530). However, the O-RU (530) cannot decode this message #3 correctly. In step 508, the O-RU (530) sends U-plane data #1 for C-plane message #1, but the U-plane data #1 is discarded if the O-RU (530) receives it. In step 510, the O-RU (530) sends U-plane data #2 for C-plane message #2. In step 512, the O-RU (530) sends an ACK/NACK message with the following: (1) C-plane #1=ACK and (2) C-plane #3=NACK.

[76] Fig. 6 illustrates an example of a message flow 600 for fault-tolerant transmission and reception of messages according to an embodiment of the present disclosure. The message flow 600 may be implemented by a network entity (e.g., networks 102 and 200, as illustrated in Fig. 2) and/or a client device (e.g., 106-114, as illustrated in Fig. 1). The embodiment of the message flow 600 shown in Fig. 5 serves for illustration only. One or more components illustrated in Fig. 5 may be implemented in a dedicated circuit configured to perform the functions mentioned, or one or more components may be implemented by one or more processors executing instructions in order to perform the functions mentioned.

[77] For example, O-DU 620 may be implemented in one of the network entities in 102, in server 104, and/or in base stations 116 and 118. In particular, base station 116 and 118 may be implemented in gNB, which includes a logical node that hosts RLC/MAC/upper PHY layer based on functional partitioning at lower layers. For example, O-RU 630 may be implemented in base stations 116 and 118. In particular, base station 116 and 118 may be implemented in RRH or TRP, which includes a logical node that hosts lower PHY layer and RF processing based on functional partitioning at lower layers.

[78] As illustrated in FIG. 6, in step 602, the O-DU (620) sends C-plane messages to the O-RU (630). During the transmission, the C-plane message (Ext=xx, ack-ReqSeqId=S13) is discarded after Ext=xx is decoded in slot #n. For example, in this case, “xx” may be set to “22”. In step 604, the O-RU (630) sends an ACK message (numberofACKs=2, ackSeqId=SI ₁ , SI ₂ , numberofNACKs=1, nackSeqId=SI ₃ ) to the O-DU (630). Based on nackSeqId set equal to SI ₃ , the O-DU knows that SI ₃ sent in slot #n in step 604 is discarded after Ext=xx is decoded. In step 606, the C-plane message (Ext=xx, ackReqSeqId=SI ₁ ) is lost or discarded before Ext=xx is decoded. In step 608, the O-DU (620) retransmits the C-plane message (Ext=xx, ackReqSeqId=SI ₃ ) to the O-RU (630). At the end of slot #n+2, the O-DU knows that SI ₁ sent in slot #n+1 in step 606 is lost or discarded before Ext=xx is decoded. In step 610, the O-RU (630) transmits an ACK message (numberofACKs=1, ackSeqId=SI ₃ ). In step 612, the O-DU (620) retransmits the C-plane message (Ext=xx, ackReqSeqId=SI ₁ ) in slot #n+3.

[79] Fig. 7 illustrates another example of a message sequence 700 for fault-tolerant transmission and reception of messages according to an embodiment of the present disclosure. The message sequence 700 may be performed by a network entity (e.g., networks 102 and 200, as illustrated in Fig. 2) and/or a client device (e.g., 106-114, as illustrated in Fig. 1). The embodiment of the message sequence 700 shown in Fig. 7 serves for illustration only. One or more components illustrated in Fig. 7 may be implemented in a dedicated circuit configured to perform the functions mentioned, or one or more components may be implemented by one or more processors executing instructions in order to perform the functions mentioned.

[80] For example, O-DU 720 may be implemented in one of the network entities in 102, in server 104, and/or in base stations 116 and 118. In particular, base station 116 and 118 may be implemented in gNB, which includes a logical node that hosts RLC/MAC/upper PHY layer based on functional partitioning in lower layers. For example, O-RU 730 may be implemented in base stations 116 and 118. In particular, base station 116 and 118 may be implemented in RRH or TRP, which includes a logical node that hosts lower PHY layer and RF processing based on functional partitioning in lower layers.

[81] As illustrated in FIG. 7, in step 702, the O-DU (720) sends C-plane messages to the O-RU (730). During transmission, the C-plane message (Ext=xx, ack-ReqSeqId=S12) for the symbol M is lost or discarded before "Ext=xx" is decoded. In step 702, the C-plane message (Ext=xx, ackReqSeqId=S13) for the symbol M is discarded after Ext=xx is decoded. In step 702, the C-plane message (Ext=xx, ackReqSeqId=SI1) for the symbol M is received and correctly decoded. In step 704, the O-RU (730) transmits an ACK/NACK message (numberofACKs=1, ackSeqId=SI1, numberofNACKs=1, nackSeqId=SI3) after Ta3_min_cp_ack from the air interface transmission time for the M symbol, which is the start of the UL transmission window in the C-plane, when Tax_min_cp_ack may be equal to 0 or a negative value. In step 702, the O-DU receives an ACK/NACK message (numberofACKs=1, ackSeqId=SI1, numberofNACKs=1, nackSeqId=SI3) between the start of the UL reception window in the U-plane and the end of the UL reception window in the U-plane. The O-DU recognizes that SI2 is discarded before Ext=xx is decoded, and SB is discarded after Ext=xx is decoded. The O-DU may decide to retransmit the discarded section descriptions.

[82] Fig. 8 illustrates an example of a message format 800 according to embodiments of the present disclosure. The embodiment of the message format 800 shown in Fig. 8 is for illustrative purposes only.

[83] In one embodiment, the AckNackRequest section extension format is provided as shown in Fig. 8.

[84] Table 1 shows a description of the new fields provided for the AckNAckRequest section extension format, as illustrated in Figure 8.

[85] Table 1

Fields

Field Description Value ranges Field length extType This represents an existing field, a new value "AckNAckRequest section extension" is newly provided. The value of the AckNAckRequest section extension may be any value (e.g. set to "22") that is not used by another section extension in the O-RAN specification. The presence of this section extension indicates that the O-RU may report the ACK/NACK status if the description of the corresponding section in the C-plane message is Request for the subject of the AckNAckRequest section 7 bits extLen This is an existing field and the value of this field can be set to "1". The value 1 indicates that the size of this newly provided extension is 4 octets. 1 8 bits ackNackReqId (for example, ackNackReqSeqId) Newly provided field in the new Section Extension message. This field specifies the sequence identifier to be used when generating ACK/NACK status messages in O-DU 0 ~ 65534. The value 65535 is reserved. 16 bits

[86] Table 2 shows a description of the format of messages of type #8.

[87] Table 2

Message format type #8

Field Description Value ranges Field length numberofACKs Specifies the number of ACK sequence identifiers (ackSeqId) included in the message. 1-255 7 bits ackId (e.g. ackSeqId) Specifies the sequence identifier of a correctly decoded section description included in the AckNAckRequest section extension appended to the end of the section description. 0 ~ 65534 8 bits numberOfNACKs Specifies the number of NACK sequence identifiers (nackSeqId) included in the message. 1-255 16 bits nackId (e.g. nackSeqId) Specifies the identifier of the section description sequence for which decoding fails. 0 ~ 655334 16 bits

[88] Fig. 9 illustrates another example of a message format 900 according to embodiments of the present disclosure. The embodiment of the message format 900 shown in Fig. 9 is for illustrative purposes only.

[89] As illustrated in Fig. 9, message format 900 includes the following fields:

[90] Transport Header Field: This field specifies basic data routing capabilities, including a description of the data flow type, source and destination port identifiers, the ability to support concatenation of multiple application messages in a single Ethernet packet, and the assignment of sequence numbers,

[91] Reserved Field: This field is reserved for future use,

[92] Operational Data Version Field: This field indicates the version of the operational data management protocol,

[93] FrameId field: This field specifies the frame identification data and a counter for 10-ms frames,

[94] SubframeID field: This field specifies the subframe identification data and a counter for the 1-ms subframe,

[95] SlotId field: This field specifies the slot number in the 1-ms subframe,

[96] SymbolId field: This field specifies the symbol number,

[97] SetionType field: This field specifies the characteristics of the U-plane data,

[98] numberOfAcks field: This field specifies the number of ACKs,

[99] numbeOfNacks field: This field specifies the number of NACKs,

[100] ackId field: This field specifies the ACK identification data,

[101] nackId field: This field specifies the identification data for the NACK, and

[102] Padding field: This field is used to align with a 32-bit boundary.

[103] FIG. 10 illustrates a flow chart of a method 1000 for fault-tolerant transmission and reception of messages over a forward backhaul network according to embodiments of the present disclosure. The method 1000 may be performed by an O-DU (e.g., a transmitter), such as a network entity (e.g., networks 102, 104, 116, 118, and 200, as illustrated in FIG. 2) and/or a client device (e.g., 106-114, as illustrated in FIG. 1). The embodiment of the method 1000 shown in FIG. 10 serves for illustration only. One or more components illustrated in FIG. 10 may be implemented in a dedicated circuit configured to perform the functions mentioned, or one or more components may be implemented by one or more processors executing instructions in order to perform the functions mentioned.

[104] As illustrated in FIG. 10, method 1000 may be implemented by means of an O-DU. The O-DU may be implemented in a base station and communicate with an O-RU (e.g., a receiving device). The O-RU may be implemented in an RRH or a TRP. A direct backhaul link between the O-DU and the O-RU is established to support fault-tolerant transmission of messages between the O-DU and the O-RU. The O-DU may include an RLC protocol layer, a MAC protocol layer, and a PHY protocol layer. The O-RU may include a lower PHY layer and an RF layer.

[105] In one embodiment, protocol stacks including an RLC protocol layer, a MAC protocol layer, a PHY protocol layer, and an RF layer can be flexibly implemented regardless of specific hardware or device type. In other words, such a protocol stack can be freely implemented in any type of electronic device to perform the role of an O-DU and an O-RU as mentioned in this disclosure.

[106] As illustrated in Fig. 10, in step 1002, a DU (e.g., an O-DU) of a base station generates a section extension for an ACK/NACK request including an ackNackReqId field and an extLen field, wherein the ackNackReqId field indicates an identifier of the ACK/NACK request for describing the sections, and the extLen field indicates a size of the section extension.

[107] Then, in step 1004, the DU transmits to the RU a C-plane message including the extension sections for the ACK/NACK request.

[108] Finally, in step 1006, the DU receives, from the RU, an ACK message corresponding to the C-plane message.

[109] In one embodiment, the ACK message includes a numberOfAcks field indicating the number of ACKs included in the ACK message and an ackId field indicating that the section description included in the C-plane message has been correctly received and decoded by the RU, where the ackId field corresponds to the ackNackReqId of the section description.

[110] In one embodiment, the ACK message includes a numberOfNacks field indicating the number of NACKs included in the ACK message and a nackId field indicating that the section description included in the C-plane message was not received correctly by the RU, where the nackId field corresponds to the ackNackReqId of the section description.

[111] In one embodiment, the DU transmits a set of C-plane messages, and each C-plane message includes section extensions, respectively.

[112] In one embodiment, the DU identifies an ACK reception window comprising a minimum window value (ta3_min ack) and a maximum window value (ta3_max_ack) for a symbol M to receive an ACK message including at least one of ackId or nackId, where the symbol M is a startSymbolId value in a C-plane message carrying the section extension, determines whether the ACK message or the NACK message is received within the ACK reception window, and the DU further retransmits another section description based on the determination that the ACK message or the NACK message is not received within the ACK reception window. In such an embodiment, the other section description is the same as the section description or a new section description that is updated with respect to the section description or skipping the retransmission of the section description based on the determination that the ACK message is not received within the ACK reception window. In such an embodiment, ta3_min_ack and ta3_max_ack are measured between reception at the RU antenna and reception at the RU port.

[113] In one embodiment, the DU identifies an ACK reception window for a symbol M to receive an ACK message including an ackId and a nackId, where the symbol M is a startSymbolId value in a C-plane message carrying a section extension to determine whether or not an ACK message received within the ACK reception window includes a nackId, and the DU further retransmits, based on the nackId, a description of the sections to the RU.

[114] In one embodiment, the DU determines whether or not the ACK message includes a NACK identifier (nackId) and skips transmitting, to the RU, a U-plane message corresponding to the C-plane message including a section description corresponding to the nackId when the ACK message is received before sending the C-plane message.

[115] FIG. 11 illustrates a flow chart of a method 1100 for fault-tolerant transmission and reception of messages over a forward backhaul network according to embodiments of the present disclosure. Method 1100 may be performed by an O-RU (e.g., a receiving device), such as a network entity (e.g., networks 102, 104, 116, 118, and 200, as illustrated in FIG. 2) and/or a client device (e.g., 106-114, as illustrated in FIG. 1). The embodiment of method 1100 shown in FIG. 11 serves for illustration only. One or more components illustrated in FIG. 11 may be implemented in a dedicated circuit configured to perform the functions mentioned, or one or more components may be implemented by one or more processors executing instructions in order to perform the functions mentioned.

[116] As illustrated in FIG. 11, method 1100 may be implemented by an O-RU. The O-RU may be implemented in a base station and communicate with an O-DU (e.g., a transmitter). The O-RU may be implemented in an RRH, a TRP, or a UE. A direct backhaul link between the O-DU and the O-RU is established to support fault-tolerant messaging between the O-DU and the O-RU.

[117] As illustrated in Fig. 11, method 1100 begins at step 1102. At step 1102, the RU receives, from the DU, a C-plane message including extension sections for an ACK/NACK request.

[118] Then, in step 1104, the RU identifies a section extension included in the C-plane message for the ACK/NACK request that includes an ackNackReqId field and an extLen field. In one example, the ackNackReqId field indicates the identifier of the ACK/NACK request for a section description, and the extLen field indicates the size of the section extension.

[119] Finally, in step 1106, the RU transmits to the DU an ACK message corresponding to the C-plane message.

[120] In one embodiment, the ACK message includes a numberOfAcks field indicating the number of ACKs included in the ACK message and an ackId field indicating that the section description included in the C-plane message has been correctly received by the RU, where the ackId field corresponds to the ackNackReqId of the section description.

[121] In one embodiment, the ACK message includes a numberOfNacks field indicating the number of NACKs included in the ACK message and a nackId field indicating that the section description included in the C-plane message was not received correctly by the RU, where the nackId field corresponds to the ackNackReqId of the section description.

[122] In one embodiment, the RU receives a set of C-plane messages, wherein each C-plane message includes an extension of sections, respectively.

[123] In one embodiment, the RU receives a retransmission of the section description based on a determination that the ACK message is not received within an ACK receive window comprising ta3_min ack and ta3_max_ack, where the retransmitted section description is the same as the section description that was previously received or a new section description that is updated with respect to the previously received section description. The ACK receive window is identified for a symbol M to receive the ACK message that includes at least one of ackId or nackId, where the symbol M is the value of start-SymbolId in the C-plane message carrying the section extension, and ta3_min_ack and ta3_max_ack measured between reception at the RU antenna and reception at the RU port.

[124] In one embodiment, the RU receives, based on the nackId, a retransmission of the section description to the RU, and an ACK receive window is identified for a symbol M to receive an ACK message including the ackId and the nackId, where the symbol M is the value of startSymbolId in a C-plane message carrying the section extension.

[125] In one embodiment, the RU skips receiving, from the DU, a C-plane message including a section description corresponding to the nackId when an ACK message is received before sending the C-plane message.

[126] Fig. 12 illustrates an example of a direct transit interface 1200 according to embodiments of the present disclosure. The embodiment of the direct transit interface 1200 shown in Fig. 12 is for illustrative purposes only.

[127] As illustrated in FIG. 12, network architecture 1200 includes a UE 1202 (e.g., 106-114, as illustrated in FIG. 1), a base station (BS) 1212 (e.g., 104, 116, and 118, as illustrated in FIG. 1), and a core network 1210. BS 1212 further comprises an antenna 1204, a radio interface 1206, and a baseband 1208. UE 1202 and BS 1212 are connected via a radio interface. BS 1212 and core network 1210 are connected via a reverse backhaul interface. Antenna 1204 and radio interface 1206 are connected via an RF interface, and radio interface 1206 and baseband 1208 are connected via a forward backhaul interface.

[128] The DL/UL control message may be transmitted and received between the air interface 1206 and the baseband 1208. The transmitter and receiver may be implemented on the air interface 1206 and/or the baseband 1208 to transmit and receive the DL/UL control message.

[129] In the current xRAN/O-RAN specification, 5 possible compression technologies are used to ensure the efficient utilization of the forward backhaul bandwidth (BW). Among these possible technologies, from the point of view of the ease of implementation, block floating is a good possible technology. From the point of view of BW efficiency, modulation compression is strongly recommended for DL. The incentive of “modulation compression” shows an ideal picture to ensure the efficient BW of the forward backhaul with ideal compression performance without any loss of system performance. But regarding “modulation compression”, there are some functional defects that need to be corrected in the current specification. Thus, the coexistence of several different data in the PRB after RE transformation. In addition, the “power offset” information for each channel is required for clarification.

[130] According to embodiments, a base station transmitter is provided for processing an acknowledgement of a control plane (C-plane) message in a wireless communication system. The transmitter comprises a processor configured to generate a section extension for an acknowledgement/denial of receipt (ACK/NACK) request that includes an ACK/NACK request identifier field (ackNackReqId) and a length field (extLen). The ackNackReqId field indicates an ACK/NACK request identifier of a section description, and the extLen field indicates a size of the section extension. The transmitter comprises a transceiver operatively coupled to the processor. The transceiver is configured to transmit, to a receiver, a C-plane message that includes the section extension for the ACK/NACK request, and to receive, from the receiver, an ACK message corresponding to the C-plane message.

[131] In some embodiments,

[132] In some embodiments, the ACK message includes a NACK numberOfNacks field indicating the number of NACKs included in the ACK message. The ACK message includes a NACK identifier (nackId) field indicating that the section description included in the C-plane message was not received correctly by the receiving device. The nackId field corresponds to the ackNackReqId of the section description.

[133] In some embodiments, the transceiver is further configured to transmit a set of C-plane messages. Each C-plane message includes an extension of sections, respectively.

[134] In some embodiments, the processor is further configured to identify an ACK reception window comprising a minimum window value (ta3_min ack) and a maximum window value (ta3_max_ack) for a symbol M to receive an ACK message including at least one of an ACK identifier (ackId) or a NACK identifier (nackId). The symbol M is a value of an identifier (startSymbolId) of a starting symbol in a C-plane message carrying an extension of sections. Ta3_min_ack and ta3_max_ack measured between reception at the antenna of the receiving device and reception at the port of the receiving device. The processor is further configured to determine whether or not the ACK message is received within the ACK reception window. The transceiver is further configured to retransmit another description of the sections based on the determination that the ACK message or the NACK message is not received within the ACK reception window. Another section description is the same as the section description or a new section description that is updated with respect to the section description or skipping the retransmission of the section description based on the determination that the ACK message or NACK message is not received within the ACK receive window.

[135] In some embodiments, the processor is further configured to identify an ACK reception window for a symbol M to receive an ACK message including an ACK identifier (ackId) and a NACK identifier (nackId). The symbol M is a value of an identifier (startSymbolId) of a starting symbol in a C-plane message carrying an extension of sections. The processor is further configured to determine whether or not an ACK message received within the ACK reception window includes a nackId. The transceiver is further configured to retransmit, based on the nackId, a description of the sections to the receiver.

[136] In some embodiments, the processor is further configured to determine whether or not the ACK message includes a NACK identifier (nackId). The processor is further configured to skip transmitting, to the receiving device, a user plane (U-plane) message corresponding to the C-plane message including a section description corresponding to the nackId in the ACK message.

[137] According to embodiments, a receiving device for transmitting an acknowledgement of a control plane (C-plane) message in a wireless communication system. The receiving device comprises a transceiver configured to receive, from a transmitting device, a C-plane message that includes an extension of sections for an acknowledgment/denial of receipt (ACK/NACK) request. The receiving device comprises a processor operatively connected to the transceiver, wherein the processor is configured to identify the extension of sections included in the C-plane message for the ACK/NACK request that includes an ACK/NACK request identifier field (ackNackReqId) and a length field (extLen). The ackNackReqId field indicates the identifier of the ACK/NACK request of the description of sections, and the extLen field indicates the size of the extension of sections. The receiving and transmitting device is further configured to transmit, to the transmitting device, an ACK message corresponding to the C-plane message.

[138] In some embodiments, the ACK message includes an ACK number (numberOfAcks) field indicating the number of ACKs included in the ACK message. The ACK message includes an ACK identifier (ackId) field indicating that the section description included in the C-plane message has been correctly received by the receiving device, wherein the ackId field corresponds to the ackNackReqId of the section description.

[139] In some embodiments, the ACK message includes a NACK numberOfNacks field indicating the number of NACKs included in the ACK message. The ACK message includes a NACK identifier (nackId) field indicating that the section description included in the C-plane message was not received correctly by the receiving device, wherein the nackId field corresponds to the ackNackReqId of the section description.

[140] In some embodiments, the transceiver is further configured to receive a set of C-plane messages, wherein each C-plane message includes an extension of sections, respectively.

[141] In some embodiments,

[142] In some embodiments, the transceiver is further configured to receive, based on the nackId, a retransmission of the section description to the receiver. An ACK reception window is identified for a symbol M to receive an ACK message including an ACK identifier (ackId) and a NACK identifier (nackId). The symbol M is the value of the identifier (startSymbolId) of the starting symbol in the C-plane message carrying the section extension.

[143] In some embodiments, the processor is further configured to skip receiving from the transmitting device. The C-plane message includes a section description corresponding to the nackId when the ACK message is received before sending the C-plane message.

[144] According to embodiments, a method is provided for a base station transmitter for processing an acknowledgement of a control plane (C-plane) message in a wireless communication system. The method comprises generating a section extension for an acknowledgement/negation of receipt (ACK/NACK) request, including an ACK/NACK request identifier field (ackNackReqId) and a length field (extLen). The ackNackReqId field indicates an ACK/NACK request identifier of a section description, and the extLen field indicates a size of the section extension.

[145] The method comprises transmitting, to a receiving device, a C-plane message including an extension of sections for an ACK/NACK request. The method comprises receiving, from the receiving device, an ACK message corresponding to the C-plane message.

[146] In some embodiments, the ACK message includes an ACK number (numberOfAcks) field indicating the number of ACKs included in the ACK message. The ACK message includes an ACK identifier (ackId) field indicating that the section description included in the C-plane message has been correctly received by the receiving device, wherein the ackId field corresponds to the ackNackReqId of the section description.

[147] In some embodiments, the ACK message includes a NACK numberOfNacks field indicating the number of NACKs included in the ACK message. The ACK message includes a NACK identifier (nackId) field indicating that the section description included in the C-plane message was not received correctly by the receiving device, wherein the nackId field corresponds to the ackNackReqId of the section description.

[148] In some embodiments, the method further comprises transmitting a set of C-plane messages. Each C-plane message includes an extension of sections, respectively.

[149] In some embodiments, the method further comprises identifying an ACK reception window comprising a minimum window value (ta3_min_ack) and a maximum window value (ta3_max_ack) for a symbol M to receive an ACK message including at least one of an ACK identifier (ackId) or a NACK identifier (nackId). The symbol M is a value of an identifier (startSymbolId) of a starting symbol in a C-plane message carrying section extension. Ta3_min_ack and ta3_max_ack measured between reception at the antenna of the receiving device and reception at the port of the receiving device. The method further comprises determining whether or not the ACK message is received within the ACK reception window. The method further comprises performing one of retransmitting another section description based on determining that the ACK message or NACK message is not received within the ACK reception window, the other section description is the same as the section description or a new section description that is updated with respect to the section description, or skipping retransmitting the section description based on determining that the ACK message or NACK message is not received within the ACK reception window.

[150] In some embodiments, the method further comprises identifying an ACK reception window for a symbol M to receive an ACK message that includes an ACK identifier (ackId) and a NACK identifier (nackId). The symbol M is a value of an identifier (startSymbolId) of a starting symbol in a C-plane message carrying an extension of sections. The method further comprises determining whether or not an ACK message received within the ACK reception window includes a nackId. The method further comprises retransmitting, based on the nackId, a description of the sections to the receiving device.

[151] According to embodiments, a method is performed by an open radio access network (O-RAN) distributed unit (O-DU). The method comprises transmitting, to an O-RAN radio unit (O-RU) via a forward backhaul interface, one or more control plane (C-plane) messages. The method comprises receiving, from the O-RU via the forward backhaul interface, an acknowledgement (ACK)/denial of acceptance (NACK) feedback message for the one or more C-plane messages. Each C-plane message of the one or more C-plane messages includes section extension information for an ACK/NACK request. The section extension information includes a request identifier used to identify a section description for which ACK/NACK feedback is requested. The ACK/NACK feedback message includes at least one of ACK information for indicating a request identifier of a correctly decoded section description or NACK information for indicating a request identifier of an incorrectly decoded section description.

[152] For example, an incorrectly decoded section description is discarded after the section extension information associated with the incorrectly decoded section description is decoded.

[153] For example, the section extension information includes an extension type for an ACK/NACK request and an extension length indicating the size of the section extension information as one word corresponding to 4 bytes. The extension type is indicated by 7 bits of the section extension information. The extension length is indicated by 8 bits of the section extension information. The request identifier is indicated by 16 bits of the section extension information.

[154] For example, the method further comprises, based on identifying that the ACK/NACK status of the section description in one or more C-plane messages is not received by the end of the reception window, identifying that the section description is discarded before section extension information corresponding to the discarded section description is decoded.

[155] For example, the ACK/NACK Feedback message is associated with a C-plane message and includes a transport header and an application header. The application header includes a frame identifier, a subframe identifier, a slot identifier, a start symbol identifier, a number of sections, and a section type indicating the section type 8 for sending the ACK/NACK from the O-RU to the O-DU. The ACK/NACK Feedback message includes information for indicating the number of ACKs included in the ACK/NACK Feedback message and information for indicating the number of NACKs included in the ACK/NACK Feedback message. The number of ACKs is indicated by 8 bits of the ACK/NACK Feedback message. The number of NACKs is indicated by 8 bits of the ACK/NACK Feedback message.

[156] According to embodiments, a method is performed by an open radio access network (O-RAN) radio unit (O-RU). The method comprises receiving, from a distributed O-RAN unit (O-DU) via a forward backhaul interface, one or more control plane (C-plane) messages. The method comprises transmitting, to the O-RU via the forward backhaul interface, an acknowledgement (ACK)/denial of acceptance (NACK) feedback message for the one or more C-plane messages. Each C-plane message of the one or more C-plane messages includes section extension information for an ACK/NACK request. The section extension information includes a request identifier used to identify a section description for which ACK/NACK feedback is requested. The ACK/NACK feedback message includes at least one of ACK information for indicating a request identifier of a correctly decoded section description or NACK information for indicating a request identifier of an incorrectly decoded section description.

[157] For example, an incorrectly decoded section description is discarded after the section extension information associated with the incorrectly decoded section description is decoded.

[158] For example, the section extension information includes an extension type for an ACK/NACK request and an extension length indicating the size of the section extension information as one word corresponding to 4 bytes. The extension type is indicated by 7 bits of the section extension information. The extension length is indicated by 8 bits of the section extension information. The request identifier is indicated by 16 bits of the section extension information.

[159] For example, the ACK/NACK feedback message is transmitted within the ACK transmission window.

[160] For example, the ACK/NACK feedback message is associated with a C-plane message and includes a transport header and an application header. The application header includes a frame identifier, a subframe identifier, a slot identifier, a start symbol identifier, a number of sections, and a section type indicating the type of section 8 for sending ACK/NACK from the O-RU to the O-DU. The ACK/NACK feedback message includes information for indicating the number of ACKs included in the ACK/NACK feedback message and information for indicating the number of NACKs included in the ACK/NACK feedback message. The number of ACKs is indicated by 8 bits of the ACK/NACK feedback message. The number of NACKs is indicated by 8 bits of the ACK/NACK feedback message.

[161] According to embodiments, an open radio access network (O-RAN) distributed unit (O-DU) device comprises at least one transceiver and at least one processor coupled to the at least one transceiver. The at least one processor is configured to control the at least one transceiver to transmit, to an O-RAN radio unit (O-RU) via a forward backhaul interface, one or more control plane (C-plane) messages. The at least one processor is configured to control the at least one transceiver to receive, from the O-RU via a forward backhaul interface, an acknowledgement (ACK)/negation (NACK) feedback message for the one or more C-plane messages. Each C-plane message of the one or more C-plane messages includes section extension information for an ACK/NACK request. The section extension information includes a request identifier used to identify a section description for which ACK/NACK feedback is requested. The ACK/NACK feedback message includes at least one of ACK information to indicate a request identifier of a correctly decoded section description or NACK information to indicate a request identifier of an incorrectly decoded section description.

[162] For example, an incorrectly decoded section description is discarded after the section extension information associated with the incorrectly decoded section description is decoded.

[163] For example, the section extension information includes an extension type for an ACK/NACK request and an extension length indicating the size of the section extension information as one word corresponding to 4 bytes. The extension type is indicated by 7 bits of the section extension information. The extension length is indicated by 8 bits of the section extension information. The request identifier is indicated by 16 bits of the section extension information.

[164] For example, at least one processor is further configured to, based on identifying that the ACK/NACK status of the section description in one or more C-plane messages is not received by the end of the receive window, identifying that the section description is discarded before section extension information corresponding to the discarded section description is decoded.

[165] For example, the ACK/NACK Feedback message is associated with a C-plane message and includes a transport header and an application header. The application header includes a frame identifier, a subframe identifier, a slot identifier, a start symbol identifier, a number of sections, and a section type indicating the type of section 8 for sending ACK/NACK from the O-RU to the O-DU. The ACK/NACK Feedback message includes information for indicating the number of ACKs included in the ACK/NACK Feedback message and information for indicating the number of NACKs included in the ACK/NACK Feedback message. The number of ACKs is indicated by 8 bits of the ACK/NACK Feedback message. The number of NACKs is indicated by 8 bits of the ACK/NACK Feedback message.

[166] According to embodiments, an open radio access network (O-RAN) radio unit (O-RU) device, for the method, comprises at least one transceiver and at least one processor coupled to the at least one transceiver. The at least one processor is configured to control the at least one transceiver to receive, from an O-RAN distributed unit (O-DU) via a forward backhaul interface, one or more control plane (C-plane) messages. The at least one processor is configured to control the at least one transceiver to transmit, to the O-RU via a forward backhaul interface, an acknowledgement (ACK)/negation (NACK) feedback message for the one or more C-plane messages. Each C-plane message of the one or more C-plane messages includes section extension information for an ACK/NACK request. The section extension information includes a request identifier used to identify a section description for which ACK/NACK feedback is requested. The ACK/NACK feedback message includes at least one of ACK information to indicate a request identifier of a correctly decoded section description or NACK information to indicate a request identifier of an incorrectly decoded section description.

[167] For example, an incorrectly decoded section description is discarded after the section extension information associated with the incorrectly decoded section description is decoded.

[168] For example, the section extension information includes an extension type for an ACK/NACK request and an extension length indicating the size of the section extension information as one word corresponding to 4 bytes. The extension type is indicated by 7 bits of the section extension information. The extension length is indicated by 8 bits of the section extension information. The request identifier is indicated by 16 bits of the section extension information.

[169] For example, the ACK/NACK feedback message is transmitted within the ACK transmission window.

[170] For example, the ACK/NACK feedback message is associated with a C-plane message and includes a transport header and an application header. The application header includes a frame identifier, a subframe identifier, a slot identifier, a start symbol identifier, a number of sections, and a section type indicating the section type 8 for sending the ACK/NACK from the O-RU to the O-DU. The ACK/NACK feedback message includes information for indicating the number of ACKs included in the ACK/NACK feedback message and information for indicating the number of NACKs included in the ACK/NACK feedback message. The number of ACKs is indicated by 8 bits of the ACK/NACK feedback message. The number of NACKs is indicated by 8 bits of the ACK/NACK feedback message.

[171] The above flow charts illustrate exemplary methods that may be implemented in accordance with the principles of the present disclosure, and various changes may be made to the methods illustrated in the flow charts herein. For example, although shown as a sequence of steps, various steps in each figure may overlap, occur in parallel, occur in a different order, or occur multiple times. In another example, steps may be omitted or replaced by other steps.

[172] Although the present disclosure has been described with reference to exemplary embodiments, various changes and modifications may occur to those skilled in the art. It is intended that the present disclosure cover such changes and modifications as fall within the scope of the appended claims. The description in this application should not be read as implying that any particular element, step, or function is an essential element that is to be included within the scope of the claims. The scope of the patentable subject matter is defined by the claims.

Claims (76)

1. A communication method implemented via an open radio access network (O-RAN) distributed unit (O-DU), wherein the method comprises the steps of: transmit, to the O-RAN radio unit (O-RU) via a forward transit interface, one or more control plane (C-plane) messages; and receive, from the O-RU via the forward transit interface, an acknowledgement (ACK)/non-acknowledgment (NACK) feedback message for these one or more C-plane messages, wherein each C-plane message of said one or more C-plane messages includes section extension information for requesting an ACK/NACK, wherein the section extension information includes a request identifier (ID) used to identify the section description for which ACK/NACK feedback is requested, and wherein the ACK/NACK feedback message includes at least one of ACK information for indicating a request identifier of a correctly decoded section description or NACK information for indicating a request identifier of an incorrectly decoded section description. 2. The method according to claim 1, wherein the incorrectly decoded section description is discarded after the section extension information associated with the incorrectly decoded section description is decoded. 3. The method according to item 1, wherein the section extension information includes an extension type for the ACK/NACK request and an extension length indicating the size of the section extension information, in the form of one word corresponding to 4 bytes, in this case, the extension type is indicated by 7 bits of section extension information, where the extension length is specified by 8 bits of section extension information, and In this case, the request ID is specified using 16 bits of section extension information. 4. The method according to claim 1, further comprising the step of: based on identifying that the ACK/NACK status of the section description in said one or more C-plane messages is not received by the end of the reception window, identifying that the section description is discarded before the section extension information corresponding to the discarded section description is decoded. 5. The method according to item 1, wherein the ACK/NACK feedback message is associated with the C-plane message and includes a transport header and an application header, wherein the application header includes a frame identifier, a subframe identifier, a slot identifier, and a section type indicating the section type 8 for sending ACK/NACK from the O-RU to the O-DU, wherein the ACK/NACK feedback message includes information for indicating the number of ACKs included in the ACK/NACK feedback message and information for indicating the number of NACKs included in the ACK/NACK feedback message, where the number of ACKs is indicated by 8 bits of the ACK/NACK feedback message, and The number of NACKs is indicated by 8 bits of the ACK/NACK feedback message. 6. A communication method implemented via an open radio access network (O-RAN) radio unit (O-RU), wherein the method comprises the steps of: receive, from an O-RAN distributed unit (O-DU) via a forward transit interface, one or more control plane (C-plane) messages; and transmit, to the O-RU via the forward transit interface, an acknowledgement (ACK)/non-acknowledgment (NACK) feedback message for these one or more C-plane messages, wherein each C-plane message of said one or more C-plane messages includes section extension information for requesting an ACK/NACK, wherein the section extension information includes a request identifier (ID) used to identify the section description for which ACK/NACK feedback is requested, and wherein the ACK/NACK feedback message includes at least one of ACK information for indicating a request identifier of a correctly decoded section description or NACK information for indicating a request identifier of an incorrectly decoded section description. 7. The method according to claim 6, wherein the incorrectly decoded section description is discarded after the section extension information associated with the incorrectly decoded section description is decoded. 8. The method according to item 6, wherein the section extension information includes an extension type for the ACK/NACK request and an extension length indicating the size of the section extension information, in the form of one word corresponding to 4 bytes, in this case, the extension type is indicated by 7 bits of section extension information, where the extension length is specified by 8 bits of section extension information, and In this case, the request ID is specified using 16 bits of section extension information. 9. The method according to claim 6, wherein the ACK/NACK feedback message is transmitted within the ACK transmission window. 10. The method according to item 6, wherein the ACK/NACK feedback message is associated with the C-plane message and includes a transport header and an application header, wherein the application header includes a frame identifier, a subframe identifier, a slot identifier, and a section type indicating the section type 8 for sending ACK/NACK from the O-RU to the O-DU, wherein the ACK/NACK feedback message includes information for indicating the number of ACKs included in the ACK/NACK feedback message and information for indicating the number of NACKs included in the ACK/NACK feedback message, where the number of ACKs is indicated by 8 bits of the ACK/NACK feedback message, and The number of NACKs is indicated by 8 bits of the ACK/NACK feedback message. 11. An open radio access network (O-RAN) distributed unit (O-DU) device comprising: at least one transmitting and receiving device; and at least one processor connected to at least one transmitting and receiving device, configured to control at least one transmitting and receiving device so as to: transmit, to the O-RAN radio unit (O-RU) via the forward transit interface, one or more control plane (C-plane) messages and receive, from the O-RU via the forward transit interface, an acknowledgement (ACK)/non-acknowledgment (NACK) feedback message for these one or more C-plane messages, wherein each C-plane message of said one or more C-plane messages includes section extension information for requesting an ACK/NACK, wherein the section extension information includes a request identifier (ID) used to identify the section description for which ACK/NACK feedback is requested, and wherein the ACK/NACK feedback message includes at least one of ACK information for indicating a request identifier of a correctly decoded section description and NACK information for indicating a request identifier of an incorrectly decoded section description. 12. The device according to item 11, wherein the section extension information includes an extension type for the ACK/NACK request and an extension length indicating the size of the section extension information, in the form of one word corresponding to 4 bytes, in this case, the extension type is indicated by 7 bits of section extension information, in this case, the extension length is indicated by 8 bits of section extension information, in this case, the request ID is specified using 16 bits of section extension information, wherein the ACK/NACK feedback message is associated with the C-plane message and includes a transport header and an application header, wherein the application header includes a frame identifier, a subframe identifier, a slot identifier, and a section type indicating the section type 8 for sending ACK/NACK from the O-RU to the O-DU, wherein the ACK/NACK feedback message includes information for indicating the number of ACKs included in the ACK/NACK feedback message and information for indicating the number of NACKs included in the ACK/NACK feedback message, where the number of ACKs is indicated by 8 bits of the ACK/NACK feedback message, and The number of NACKs is indicated by 8 bits of the ACK/NACK feedback message. 13. An open radio access network (ORAN) radio unit (O-RU) comprising: at least one transmitting and receiving device; and at least one processor connected to at least one transmitting and receiving device, configured to control at least one transmitting and receiving device so as to: receive, from an O-RAN distributed unit (O-DU) via a forward transit interface, one or more control plane (C-plane) messages and transmit, to the O-RU via the forward transit interface, an acknowledgement (ACK)/non-acknowledgment (NACK) feedback message for these one or more C-plane messages, wherein each C-plane message of said one or more C-plane messages includes section extension information for requesting an ACK/NACK, wherein the section extension information includes a request identifier (ID) used to identify the section description for which ACK/NACK feedback is requested, and wherein the ACK/NACK feedback message includes at least one of ACK information for indicating a request identifier of a correctly decoded section description and NACK information for indicating a request identifier of an incorrectly decoded section description. 14. The device according to item 13, wherein the section extension information includes an extension type for the ACK/NACK request and an extension length indicating the size of the section extension information, in the form of one word corresponding to 4 bytes, in this case, the extension type is indicated by 7 bits of section extension information, in this case, the extension length is indicated by 8 bits of section extension information, in this case, the request ID is specified using 16 bits of section extension information, wherein the ACK/NACK feedback message is associated with the C-plane message and includes a transport header and an application header, wherein the application header includes a frame identifier, a subframe identifier, a slot identifier, and a section type indicating the section type 8 for sending ACK/NACK from the O-RU to the O-DU, wherein the ACK/NACK feedback message includes information for indicating the number of ACKs included in the ACK/NACK feedback message and information for indicating the number of NACKs included in the ACK/NACK feedback message, where the number of ACKs is indicated by 8 bits of the ACK/NACK feedback message, and The number of NACKs is indicated by 8 bits of the ACK/NACK feedback message. 15. A non-volatile machine-readable medium storing instructions that, when executed by a device, instruct the device to perform one of the methods according to paragraphs 1-5. 16. A non-volatile machine-readable medium storing instructions that, when executed by a device, instruct the device to perform one of the methods according to paragraphs 6-10.