Reduction of feedback latency for network coding in wireless backhaul communication networks

Abstract

Methods, systems, and devices for wireless communications are described. An Integrated Access and Backhaul (IAB) node of a wireless backhaul communication network may receive a configuration from a central unit node indicating that network coding is enabled for a packet flow. In some cases, the IAB node may receive a first packet of a packet flow via a first wireless link from a second access node and transmit a first encoded packet generated based on network encoding the first packet via a second wireless link. In some cases, the IAB node may receive a set of encoded packets of a packet flow from one or more access nodes, and the IAB node may transmit a feedback message via a second wireless link indicating that network decoding of the set of encoded packets for recovering multiple packets is successful or unsuccessful.

Description

Technology Field

[0001] Cross-reference

[0002] This patent application claims the benefit of U.S. Provisional Application No. 62 / 926,381 filed by Akl et al. on October 25, 2019, under the title "Reducing Feedback Latency for Network Coding in Wireless Backhaul Communications Networks"; and U.S. Patent Application No. 17 / 077,780 filed by Akl et al. on October 22, 2020, under the title "Reducing Feedback Latency for Network Coding in Wireless Backhaul Communications Networks", each of which is assigned to the assignee of this application.

[0003] The following relates to wireless communication in general, and more specifically, to reducing feedback latency for network coding in wireless backhaul communication networks. Background Technology

[0004] Wireless communication systems are widely deployed to provide various types of communication content, such as voice, video, packet data, messaging, and broadcast. These systems may be able to support communication with multiple users by sharing available system resources (e.g., time, frequency, and power). Examples of such multiple access systems include fourth-generation (4G) systems, such as Long Term Evolution (LTE) systems, LTE-Advanced (LTE-A) systems, or LTE-A Pro systems, and fifth-generation (5G) systems, which may be referred to as New Radio (NR) systems. These systems may employ technologies such as Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiple Access (OFDMA), or Discrete Fourier Transform Spread Orthogonal Frequency Division Multiplexing (DFT-S-OFDM). A wireless multiple access communication system may include multiple base stations or network access nodes, each of which simultaneously supports communication to multiple communication devices, which may otherwise be known as user equipment (UE).

[0005] Some wireless communication systems may support both access and backhaul wireless communications. For example, such wireless communication systems may include nodes, which may also be referred to as anchor nodes, parent nodes, repeater nodes, or child nodes depending on where the node is located within the network, facilitating wireless communication between the UE and the network. In some cases, these wireless communication systems may apply encoding procedures to the data as it is transmitted along the nodes. Some coding techniques in networks such as access and backhaul wireless communication networks may be improved. means of solving the problem

[0006] The described techniques relate to improved methods, systems, devices, and apparatus that support reducing feedback latency for network coding in wireless backhaul communication networks. Generally, the described techniques are provided to perform network coding at intermediate integrated access and backhaul (IAB) nodes of a wireless backhaul communication network. An IAB network may include an IAB donor (or anchor) node and one or more repeater nodes downstream from the donor node. In some embodiments, the IAB network shares resources between access and backhaul links so that access traffic may be relayed over the wireless backhaul. In some cases, the same technique may be used for access links and backhaul links. IAB donor nodes may provide access and wireless backhaul functionality to child user devices (UEs) to the IAB nodes. An IAB donor may include a central unit (CU) for controlling the IAB network and one or more distributed units (DU) for scheduling child IAB nodes. An IAB donor may have a wired connection to the core network. Downstream from an IAB donor node may include one or more IAB nodes within an IAB network (also referred to as parent nodes, relay nodes, or child nodes depending on where the node is located within the IAB network), and each node wirelessly relays traffic from its child nodes (e.g., UEs, or other IAB nodes) to a parent node (e.g., an IAB donor or IAB node). A UE may wirelessly connect to a donor or IAB node within the UE's range.

[0007] The wireless communication systems described herein may support network coding operations at intermediate nodes. For example, an intermediate node may receive unencoded or raw data packets and generate encoded packets by performing network coding, such as fountain coding. Then, the intermediate node may distribute packet segments among a set of paths to a receiving UE. Encoding at the intermediate node and transmitting packet segments using a set of paths may be robust against blocking or congestion at a specific node and may establish clear endpoints (e.g., receiver and transmitter) for the encoded packets. In some cases, the intermediate node may perform network coding to reduce feedback latency. For example, an IAB intermediate node may decode received packet segments (e.g., fountain-coded packets) and report whether the decoding was successful to prompt retransmission by the transmitter. This can improve the rate of providing feedback, as the IAB intermediate node may send feedback instead of sending packets to the IAB access node over one or more hops, and as the IAB access node is solely responsible for providing feedback.

[0008] A method of wireless communications by a first access node of a wireless backhaul communication network is described. The method may include receiving a configuration from a central unit node of the wireless backhaul communication network indicating that network coding is enabled for a packet flow, receiving a first packet of the packet flow through a first wireless link from a second access node of the wireless backhaul communication network, and transmitting a first encoded packet generated based on network encoding the first packet through a second wireless link.

[0009] An apparatus for wireless communications by a first access node of a wireless backhaul communication network is described. The apparatus may include a processor, a memory coupled to the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to receive a configuration from a central unit node of the wireless backhaul communication network indicating that network coding is enabled for a packet flow, to receive a first packet of the packet flow through a first wireless link from a second access node of the wireless backhaul communication network, and to transmit a first encoded packet generated based on network encoding the first packet through a second wireless link.

[0010] Another device for wireless communications by a first access node of a wireless backhaul communication network is described. The device may include means for receiving, from a central unit node of the wireless backhaul communication network, a configuration indicating that network coding is enabled for a packet flow; means for receiving a first packet of a packet flow through a first wireless link from a second access node of the wireless backhaul communication network; and means for transmitting a first encoded packet generated based on network encoding the first packet through a second wireless link.

[0011] A non-transient computer-readable medium is described for storing code for wireless communications by a first access node of a wireless backhaul communication network. The code may include instructions executable by a processor to receive a configuration from a central unit node of the wireless backhaul communication network indicating that network coding is enabled for a packet flow, to receive a first packet of the packet flow through a first wireless link from a second access node of the wireless backhaul communication network, and to transmit a first encoded packet generated based on network encoding the first packet through a second wireless link.

[0012] In some examples of the methods, apparatuses, and non-transient computer-readable media described herein, receiving a configuration may include operations, features, means, or instructions for receiving a configuration indicating a path selection function, wherein the first encoded packet includes a path identifier of a first path among a set of different paths that may be selected based on a path selection function, and may be transmitted along the first path via a second wireless link.

[0013] Some examples of the methods, devices, and non-transient computer-readable media described herein may further include operations, features, means, or instructions for transmitting a second encoded packet that may be generated based on network encoding a first packet.

[0014] In some examples of the methods, apparatuses, and non-transient computer-readable media described herein, transmitting a second encoded packet may include operations, features, means, or instructions for transmitting the second encoded packet along a second path among a set of different paths that may be selected based on a path selection function.

[0015] In some examples of the methods, apparatuses, and non-transient computer-readable media described herein, the path selection function indicates that encoded packets are distributed uniformly or non-uniformly between sets of different paths.

[0016] Some examples of the methods, apparatuses, and non-transient computer-readable media described herein may further include operations, features, means, or instructions for receiving feedback indicating that at least one packet of a portion of data of a packet flow has been successfully received, wherein the portion of data comprises a first packet, and for receiving said feedback and transmitting a second encoded packet that may be generated based on network encoding the first packet in response to the feedback.

[0017] Some examples of the methods, apparatuses, and non-transient computer-readable media described herein may further include operations, features, means, or instructions for receiving feedback indicating that each packet from a first part of data of a packet flow has been successfully received, wherein the first part of data comprises a first packet, receiving said feedback, and transmitting a second encoded packet that may be generated based on network encoding a second packet from a second part of data of a packet flow based on the feedback.

[0018] In some examples of the methods, apparatuses, and non-transient computer-readable media described herein, the first encoded packet may be generated based on network encoding the first packet of the packet flow and at least one additional packet.

[0019] In some examples of the methods, apparatuses, and non-transient computer-readable media described herein, receiving a first packet of a packet flow over a first wireless link may include operations, features, means, or instructions for determining the destination address of the first packet and identifying a mismatch between the address of the first access node and the destination address.

[0020] Some examples of the methods, devices, and non-transient computer-readable media described herein may further include operations, features, means, or instructions for providing a first packet for network encoding based on a configuration indicating to perform network coding when an address mismatch may be identified.

[0021] In some examples of the methods, apparatuses, and non-transient computer-readable media described herein, the configuration indicates that network coding is performed when an address mismatch may be identified based on conditions for at least one of the address of a first packet, the path identifier of a first packet, a first wireless link, a second wireless link, or any combination thereof.

[0022] In some examples of the methods, apparatuses, and non-transient computer-readable media described herein, the first wireless link may be an inflow link or a wireless link control channel.

[0023] In some examples of the methods, apparatuses, and non-transient computer-readable media described herein, the second wireless link may be an egress link or a wireless link control channel.

[0024] Some examples of the methods, apparatuses, and non-transient computer-readable media described herein may further include operations, features, means, or instructions for receiving a second packet over a first wireless link, determining the destination address of the second packet, and identifying a mismatch between the address of the first access node and the destination address.

[0025] Some examples of the methods, devices, and non-transient computer-readable media described herein may further include operations, features, means, or instructions for transmitting a second packet over a second wireless link or a third wireless link based on a configuration indicating to perform packet forwarding when an address mismatch may be identified.

[0026] In some examples of the methods, apparatuses, and non-transient computer-readable media described herein, the configuration indicates that packet forwarding is performed when an address mismatch may be identified based on conditions regarding at least one of the address of a first packet, the path identifier of a first packet, a first wireless link, a second wireless link, a third wireless link, or any combination thereof.

[0027] In some examples of the methods, devices, and non-transient computer-readable media described herein, the first wireless link may be an inflow link or a wireless link control channel.

[0028] In some examples of the methods, devices, and non-transient computer-readable media described herein, the second wireless link may be an outflow link or a wireless link control channel.

[0029] In some examples of the methods, apparatuses, and non-transient computer-readable media described herein, a configuration indicating that network coding may be enabled for packet flows may be received based on a modification of the network topology.

[0030] In some examples of the methods, devices, and non-transient computer-readable media described herein, a configuration indicating that network coding may be enabled for a packet flow may be received based on a wireless link failure report.

[0031] In some examples of the methods, apparatuses, and non-transient computer-readable media described herein, a configuration indicating that network coding may be enabled for a packet flow may be received based on buffer status reporting indicating congestion.

[0032] In some examples of the methods, devices, and non-transient computer-readable media described herein, a configuration indicating that network coding may be enabled for a packet flow may be received based on the establishment, release, or modification of a wireless link control channel.

[0033] In some examples of the methods, devices, and non-transient computer-readable media described herein, receiving a configuration may include operations, features, means, or commands for receiving wireless resource control signaling or application protocol signaling indicating the configuration.

[0034] Some examples of the methods, apparatuses, and non-transient computer-readable media described herein may further include operations, features, means, or instructions for determining that the amount of data from one or more received packets of a packet flow satisfies a network coding threshold, and for performing a network encoding operation on one or more received packets of a packet flow based on the satisfaction of the network coding threshold.

[0035] Some examples of the methods, apparatuses, and non-transient computer-readable media described herein may further include operations, features, means, or instructions for network encoding a first packet, including performing a linear network encoding operation or a fountain encoding operation on the first packet.

[0036] Some examples of the methods, apparatuses, and non-transient computer-readable media described herein may further include operations, features, means, or instructions for network encoding a first portion of data of a packet flow comprising a first subset of packets of the packet flow to generate a first encoded packet, and the first subset of packets comprises the first packet.

[0037] Some examples of the methods, apparatuses, and non-transient computer-readable media described herein may further include operations, features, means, or instructions for network encoding a second portion of data of a packet flow comprising a second subset of packets of the packet flow to generate a second encoded packet.

[0038] In some examples of the methods, apparatuses, and non-transient computer-readable media described herein, a second subset of packets comprises at least one packet from a first subset of packets.

[0039] A method of wireless communications by a first access node of a wireless backhaul communication network is described. The method may include: receiving a configuration from a central unit node of the wireless backhaul communication network indicating that network coding is enabled for a packet flow; receiving a set of encoded packets of a packet flow through one or more wireless links from one or more access nodes of the wireless backhaul communication network; transmitting a first packet among a set of packets restored by network decoding of a set of encoded packets through a first wireless link along a first path among a set of different paths, wherein the first packet includes a first path identifier; and transmitting a second packet among a set of packets restored by network decoding of a set of encoded packets through a second wireless link along a second path among a set of different paths, wherein the second packet includes a second path identifier.

[0040] A device for wireless communications by a first access node of a wireless backhaul communication network is described. The device may include a processor, a memory coupled to the processor, and instructions stored in the memory. The commands may be executable by a processor to cause the device to receive a configuration indicating that network coding is enabled for a packet flow from a central unit node of a wireless backhaul communication network, to receive a set of encoded packets of a packet flow through one or more wireless links from one or more access nodes of a wireless backhaul communication network, and to transmit a first packet among a set of packets restored by network decoding of a set of encoded packets through a first wireless link along a first path among a set of different paths, wherein the first packet includes a first path identifier, and to transmit a second packet among a set of packets restored by network decoding of a set of encoded packets through a second wireless link along a second path among a set of different paths, wherein the second packet includes a second path identifier.

[0041] Another device for wireless communications by a first access node of a wireless backhaul communication network is described. The device may include means for receiving a configuration indicating that network coding is enabled for a packet flow from a central unit node of the wireless backhaul communication network; means for receiving a set of encoded packets of a packet flow through one or more wireless links from one or more access nodes of the wireless backhaul communication network; means for transmitting a first packet among a set of packets restored by network decoding of a set of encoded packets through a first wireless link along a first path among a set of different paths, said means for transmitting said first packet, said packet including a first path identifier; and means for transmitting a second packet among a set of packets restored by network decoding of a set of encoded packets through a second wireless link along a second path among a set of different paths, said second packet including a second path identifier.

[0042] A non-transient computer-readable medium is described for storing code for wireless communications by a first access node of a wireless backhaul communication network. The code may include instructions executable by a processor to receive a configuration from a central unit node of the wireless backhaul communication network indicating that network coding is enabled for a packet flow, to receive a set of encoded packets of a packet flow through one or more wireless links from one or more access nodes of the wireless backhaul communication network, and to transmit a first packet among a set of packets restored by network decoding of a set of encoded packets through a first wireless link along a first path among a set of different paths, wherein the first packet includes a first path identifier, and to transmit a second packet among a set of packets restored by network decoding of a set of encoded packets through a second wireless link along a second path among a set of different paths, wherein the second packet includes a second path identifier.

[0043] In some examples of the methods, apparatuses, and non-transient computer-readable media described herein, the first path is different from the second path.

[0044] In some examples of the methods, devices, and non-transient computer-readable media described herein, receiving a configuration may include operations, features, means, or commands for receiving wireless resource control signaling or application protocol signaling indicating the configuration.

[0045] In some examples of the methods, apparatuses, and non-transient computer-readable media described herein, receiving a set of encoded packets of a packet flow may include operations, features, means, or instructions for receiving a first encoded packet among a set of encoded packets including a first path identifier, and receiving a second encoded packet among a set of encoded packets including a second path identifier.

[0046] In some examples of the methods, apparatuses, and non-transient computer-readable media described herein, the first path identifier is different from the second path identifier.

[0047] In some examples of the methods, apparatuses, and non-transient computer-readable media described herein, receiving a set of encoded packets may include operations, features, means, or instructions for providing the first encoded packet for network decoding based on conditions in a configuration indicating to perform network decoding when an address mismatch may be identified, determining the destination address of the first encoded packet among the set of encoded packets, identifying a mismatch between the address of the first access node and the destination address, and when an address mismatch may be identified.

[0048] In some examples of the methods, apparatuses, and non-transient computer-readable media described herein, the condition may be for a destination address, a path identifier of a first encoded packet, or both.

[0049] Some examples of the methods, apparatuses, and non-transient computer-readable media described herein may further include operations, features, means, or commands for transmitting an unencoded packet through an outgoing wireless link or wireless link control channel based on conditions in a configuration indicating receiving an unencoded packet, identifying a mismatch between the address of a first access node and the destination address of the unencoded packet, and performing packet forwarding when an address mismatch may be identified.

[0050] In some examples of the methods, apparatuses, and non-transient computer-readable media described herein, the condition may be for a destination address, a path identifier of an unencoded packet, or both.

[0051] Some examples of the methods, apparatuses, and non-transient computer-readable media described herein may further include operations, features, means, or instructions for network decoding a set of encoded packets, including performing a linear network decoding operation or a fountain decoding operation on the set of encoded packets.

[0052] Some examples of the methods, apparatuses, and non-transient computer-readable media described herein may further include operations, features, means, or commands for transmitting a feedback message over a fourth wireless link indicating whether network decoding of a plurality of encoded packets for restoring a plurality of packets is successful or unsuccessful.

[0053] A method of wireless communications by a central entity node of a wireless backhaul communication network is described. The method may include the step of identifying an event to trigger the activation of network coding functionality for a packet flow by a first access node of the wireless backhaul communication network, and the step of transmitting a configuration to the first access node indicating that network coding is activated for the packet flow.

[0054] An apparatus for wireless communications by a central entity node of a wireless backhaul communication network is described. The apparatus may include a processor, a memory coupled to the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to identify an event to trigger the activation of network coding functionality for a packet flow by a first access node of the wireless backhaul communication network, and to transmit to the first access node a configuration indicating that network coding is activated for the packet flow.

[0055] Another device for wireless communications by a central entity node of a wireless backhaul communication network is described. The device may include means for identifying an event to trigger the activation of network coding functionality for a packet flow by a first access node of the wireless backhaul communication network, and means for transmitting to the first access node a configuration indicating that network coding is activated for the packet flow.

[0056] A non-transient computer-readable medium is described for storing code for wireless communications by a central entity node of a wireless backhaul communication network. The code may include instructions executable by a processor to identify an event for triggering the activation of network coding functionality for a packet flow by a first access node of the wireless backhaul communication network, and to transmit to the first access node a configuration indicating that network coding is activated for the packet flow.

[0057] In some examples of the methods, devices, and non-transient computer-readable media described herein, transmitting a configuration may include operations, features, means, or commands for transmitting a configuration that indicates a path selection function for distributing encoded packets between sets of different paths.

[0058] In some examples of the methods, apparatuses, and non-transient computer-readable media described herein, the path selection function indicates that encoded packets are distributed uniformly or non-uniformly between sets of different paths.

[0059] In some examples of the methods, devices, and non-transient computer-readable media described herein, transmitting a configuration may include operations, features, means, or instructions for transmitting a configuration indicating to perform network coding when an address mismatch may be identified.

[0060] In some examples of the methods, apparatuses, and non-transient computer-readable media described herein, the configuration indicates that network coding is performed when an address mismatch may be identified based on conditions regarding at least one of the address of a packet of a packet flow, a packet path identifier, a first wireless link, a second wireless link, or any combination thereof.

[0061] In some examples of the methods, devices, and non-transient computer-readable media described herein, the first wireless link may be an inflow link or a wireless link control channel.

[0062] In some examples of the methods, devices, and non-transient computer-readable media described herein, the second wireless link may be an outflow link or a wireless link control channel.

[0063] In some examples of the methods, devices, and non-transient computer-readable media described herein, transmitting a configuration may include operations, features, means, or instructions for transmitting a configuration indicating to perform packet forwarding when an address mismatch may be identified.

[0064] In some examples of the methods, apparatuses, and non-transient computer-readable media described herein, the configuration indicates that packet forwarding is performed when an address mismatch may be identified based on conditions regarding at least one of the address of a packet of a packet flow, a packet path identifier, a first wireless link, a second wireless link, or any combination thereof.

[0065] In some examples of the methods, devices, and non-transient computer-readable media described herein, the first wireless link may be an inflow link or a wireless link control channel.

[0066] In some examples of the methods, devices, and non-transient computer-readable media described herein, the second wireless link may be an outflow link or a wireless link control channel.

[0067] In some examples of the methods, devices, and non-transient computer-readable media described herein, identifying an event may include operations, features, means, or commands for identifying an event based on a modification of the network topology of a wireless backhaul communication network.

[0068] In some examples of the methods, devices, and non-transient computer-readable media described herein, identifying an event may include operations, features, means, or commands for identifying an event based on receiving a wireless link failure report.

[0069] In some examples of the methods, apparatuses, and non-transient computer-readable media described herein, identifying an event may include operations, features, means, or commands for identifying an event based on receiving buffer status reporting indicating congestion at one or more access nodes of a wireless backhaul communication network.

[0070] In some examples of the methods, apparatuses, and non-transient computer-readable media described herein, identifying an event may include operations, features, means, or commands for identifying an event based on the establishment, release, or modification of a wireless link control channel at one or more access nodes of a wireless backhaul communication network.

[0071] In some examples of the methods, devices, and non-transient computer-readable media described herein, identifying an event may include operations, features, means, or instructions for identifying an event based on the elapsed time period.

[0072] In some examples of the methods, devices, and non-transient computer-readable media described herein, transmitting a configuration may include operations, features, means, or commands for transmitting wireless resource control signaling or application protocol signaling indicating the configuration. Brief explanation of the drawing

[0073] FIG. 1 illustrates an example of a system for wireless communications that supports reducing feedback latency for network coding in wireless backhaul communication networks according to embodiments of the present disclosure. FIG. 2 illustrates an example of a wireless communication system that supports reducing feedback latency for network coding in wireless backhaul communication networks according to embodiments of the present disclosure. FIG. 3 illustrates an example of a coding procedure that supports reducing feedback latency for network coding in wireless backhaul communication networks according to embodiments of the present disclosure. FIG. 4 illustrates an example of a transmission path configuration that supports reducing feedback latency for network coding in wireless backhaul communication networks according to embodiments of the present disclosure. FIG. 5 illustrates an example of a protocol stack that supports reducing feedback latency for network coding in wireless backhaul communication networks according to embodiments of the present disclosure. FIG. 6 illustrates examples of wireless communication systems that support reducing feedback latency for network coding in wireless backhaul communication networks according to embodiments of the present disclosure. FIG. 7 illustrates an example of a process flow that supports reducing feedback latency for network coding in wireless backhaul communication networks according to embodiments of the present disclosure. FIG. 8 illustrates an example of a process flow that supports reducing feedback latency for network coding in wireless backhaul communication networks according to embodiments of the present disclosure. FIGS. 9 and 10 illustrate block diagrams of devices that support reducing feedback latency for network coding in wireless backhaul communication networks according to embodiments of the present disclosure. FIG. 11 illustrates a block diagram of a communication manager that supports reducing feedback latency for network coding in wireless backhaul communication networks according to embodiments of the present disclosure. FIG. 12 illustrates a diagram of a system including a device that supports reducing feedback latency for network coding in wireless backhaul communication networks according to embodiments of the present disclosure. FIGS. 13 through 17 illustrate flowcharts illustrating methods that support reducing feedback latency for network coding in wireless backhaul communication networks according to embodiments of the present disclosure. Specific details for implementing the invention

[0074] Some wireless communication systems may support an Integrated Access and Backhaul (IAB) network comprising an IAB donor (or anchor) node and one or more repeater nodes downstream from the donor node. In some embodiments, the IAB network shares resources between access and backhaul links so that access traffic may be relayed over the wireless backhaul. In some cases, the same technology may be used for the access links and backhaul links. IAB donor nodes may provide access and wireless backhaul functionality to the IAB nodes for child UEs. An IAB donor may include a central unit (CU) for controlling the IAB network and one or more distributed units (DU) for scheduling child IAB nodes. An IAB donor may have a wired connection to the core network. Downstream from an IAB donor node may include one or more IAB nodes within an IAB network (also referred to as parent nodes, relay nodes, or child nodes depending on where the node is located within the IAB network), each of which wirelessly relays traffic from its child nodes (e.g., UEs, or other IAB nodes) to a parent node (e.g., an IAB donor or IAB node). A UE may also wirelessly connect to a donor or IAB node within the UE's range.

[0075] Some wireless communication systems may support network coding operations such as fountain coding. Fountain coding may be used to improve the robustness of packet transmissions. In some systems, fountain coding may be performed by network coding layers at IAB access nodes (e.g., serving UEs directly) and at IAB donor nodes, but may not be performed at IAB intermediate nodes (e.g., between IAB access nodes and IAB donor nodes). In some cases, conventional systems using network coding may also not support multiple IAB donor DUs or UEs in a multi-access configuration with multiple IAB access nodes, because there may be multiple transmitters (e.g., multiple IAB donor DUs) or multiple receivers (e.g., multiple IAB access nodes), and therefore there may not be a clear end-to-end configuration for network-encoded packets (e.g., between transmitters and receivers).

[0076] The wireless communication systems described herein may support network coding at intermediate nodes. For example, an intermediate node may receive unencoded or raw data packets and perform network coding (e.g., fountain coding) to generate encoded packets. Then, the intermediate node may distribute packet segments among a set of paths to a receiving UE. Encoding at the intermediate node and transmitting packet segments using a set of paths may be robust against blocking or congestion at a particular node. Additionally, by performing network coding at the intermediate node, the encoded packets may have an established end-to-end configuration (e.g., between an IAB donor DU and an intermediate IAB node, or between an intermediate IAB node and an IAB access node).

[0077] In some cases, the intermediate node may perform network decoding to reduce feedback latency. For example, the IAB intermediate node may decode received packet segments (e.g., fountain-coded packets) and report whether the decoding was successful to prompt retransmission by the transmitter. This may improve the feedback rate, as the IAB intermediate node may transmit feedback instead of sending packets to the IAB access node over one or more hops, and as the IAB access node is solely responsible for providing feedback. Additionally, the IAB intermediate node may perform network decoding on received packets and then transmit the decoded packets to other (e.g., downstream) nodes. For example, the IAB intermediate node may decode multiple encoded packets and transmit one or more decoded packets over the first wireless link and one or more other decoded packets over the second wireless link. In some examples, an IAB intermediate node may transmit packets along one or more paths through wireless links, and the packets may include path identifiers.

[0078] Aspects of the present disclosure are first described in the context of wireless communication systems. Aspects of the present disclosure are further illustrated and described with reference to device diagrams, system diagrams, and flowcharts relating to reducing feedback latency for network coding in wireless backhaul communication networks.

[0079] FIG. 1 illustrates an example of a wireless communication system (100) that supports reducing feedback latency for network coding in wireless backhaul communication networks according to embodiments of the present disclosure. The wireless communication system (100) includes base stations (105), UEs (115), and a core network (130). In some examples, the wireless communication system (100) may be a Long Term Evolution (LTE) network, an LTE-Advanced (LTE-A) network, an LTE-A Pro network, or a New Radio (NR) network. In some cases, the wireless communication system (100) may support enhanced broadband communication, ultra-high reliability (e.g., mission-critical) communication, low-latency communication, or communication with low-cost and low-complexity devices.

[0080] Base stations (105) may communicate wirelessly with UEs (115) through one or more base station antennas. The base stations (105) described herein may include or be referred to by a person skilled in the art as base transceiver stations, wireless base stations, access points, wireless transceivers, node B, e-node B (eNB), next-generation node B or giga node B (any of which may be referred to as gNB), home node B, home e-node B, or other suitable terms. The wireless communication system (100) may include different types of base stations (105) (e.g., macro or small cell base stations). The UEs (115) described herein may be able to communicate with various types of base stations (105), including macro eNBs, small cell eNBs, gNBs, repeater base stations, etc., and network equipment.

[0081] Each base station (105) may be associated with a specific geographical coverage area (110) that supports communication with various UEs (115). Each base station (105) may provide communication coverage for the individual geographical coverage area (110) via communication links (125), and the communication links (125) between the base station (105) and the UE (115) may utilize one or more carriers. The communication links (125) illustrated in the wireless communication system (100) may include uplink transmissions from the UE (115) to the base station (105), or downlink transmissions from the base station (105) to the UE (115). Downlink transmissions may also be referred to as forward link transmissions, while uplink transmissions may also be referred to as reverse link transmissions.

[0082] A geographic coverage area (110) for a base station (105) may be divided into sectors that constitute a part of the geographic coverage area (110), and each sector may be associated with a cell. For example, each base station (105) may provide communication coverage for a macro cell, a small cell, a hot spot, or other types of cells, or various combinations thereof. In some examples, the base station (105) is mobile and thus may provide communication coverage for a mobile geographic coverage area (110). In some examples, different geographic coverage areas (110) associated with different technologies may overlap, and overlapping geographic coverage areas (110) associated with different technologies may be supported by the same base station (105) or by different base stations (105). The wireless communication system (100) may include, for example, a heterogeneous LTE / LTE-A / LTE-A Pro or NR network in which base stations (105) of different types provide coverage for various geographical coverage areas (110).

[0083] The term “cell” refers to a logical communication entity used for communication with a base station (105) (e.g., on a carrier) and may be associated with an identifier (e.g., physical cell identifier (PCID), virtual cell identifier (VCID)) to distinguish neighboring cells operating on the same or different carriers. In some examples, the carrier may support multiple cells, and different cells may be configured according to different protocol types (e.g., machine type communication (MTC), narrowband Internet of Things (NB-IoT), enhanced mobile broadband (eMBB), etc.) that may provide access to different types of devices. In some cases, the term “cell” may refer to a part (e.g., a sector) of the geographical coverage area (110) on which the logical entity operates.

[0084] UEs (115) may be scattered throughout the wireless communication system (100), and each UE (115) may be stationary or mobile. A UE (115) may also be referred to as a mobile device, a wireless device, a remote device, a handheld device, or a subscriber device, or any other suitable term, wherein “device” may also be referred to as a unit, a station, a terminal, or a client. A UE (115) may also be a personal electronic device such as a cellular phone, a personal digital assistant (PDA), a tablet computer, a laptop computer, or a personal computer. In some examples, a UE (115) may also refer to a wireless local loop (WLL) station, an Internet of Things (IoT) device, an Internet of Everything (IoE) device, or an MTC device, etc., which may be implemented in various articles such as appliances, carriers, instruments, etc.

[0085] Some UEs (115), such as MTCs or IoT devices, may be low-cost or low-complexity devices and may provide automated communication between machines (e.g., via machine-to-machine (M2M) communication). M2M communication or MTC may refer to data communication technologies that enable devices to communicate with each other or with a base station (105) without human intervention. In some examples, M2M communication or MTC may include communication from devices that incorporate sensors or instruments for measuring or capturing information and relaying that information to a central server or application program, the central server or application program may make the information available or present the information to humans interacting with the program or application. Some UEs (115) may be designed to collect information or enable automated behavior of machines. Examples of applications for MTC devices include smart metering, inventory monitoring, water level monitoring, equipment monitoring, healthcare monitoring, wildlife monitoring, weather and geological event monitoring, vehicle management and tracking, remote security sensing, physical access control, and transaction-based business billing.

[0086] Some UEs (115) may be configured to employ operating modes that reduce power consumption, such as half-duplex communication (e.g., a mode that supports one-way communication through transmission or reception rather than simultaneous transmission and reception). In some examples, half-duplex communication may be performed at a reduced peak rate. Other power conservation techniques for the UEs (115) include entering a power-saving "deep sleep" mode when not engaged in active communication or when operating on a limited bandwidth (e.g., according to narrowband communication). In some cases, the UEs (115) may be designed to support critical functions (e.g., mission-critical functions), and the wireless communication system (100) may be configured to provide ultra-reliable communication for these functions.

[0087] In some cases, the UE (115) may also be able to communicate directly with other UEs (115) (e.g., using peer-to-peer (P2P) or device-to-device (D2D) protocols). One or more of the groups of UEs (115) utilizing D2D communication may be within the geographical coverage area (110) of the base station (105). Other UEs (115) in such a group may be outside the geographical coverage area (110) of the base station (105) or otherwise may not be able to receive transmissions from the base station (105). In some cases, the groups of UEs (115) communicating via D2D communication may utilize a one-to-many (1:M) system, where each UE (115) transmits to all other UEs (115) in the group. In some cases, the base station (105) facilitates the scheduling of resources for D2D communication. In other cases, D2D communication is performed between UEs (115) without the involvement of the base station (105).

[0088] Base stations (105) may communicate with the core network (130) and with each other. For example, base stations (105) may interface with the core network (130) through backhaul links (132) (e.g., through S1, N2, N3, or other interfaces). Base stations (105) may communicate with each other directly (e.g., directly between base stations (105)) or indirectly (e.g., through the core network (130)) over backhaul links (134) (e.g., through X2, Xn, or other interfaces).

[0089] The core network (130) may provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. The core network (130) may be an advanced packet core (EPC) that may include at least one mobility management entity (MME), at least one serving gateway (S-GW), and at least one packet data network (PDN) gateway (P-GW). The MME may manage non-access stratum (e.g., control plane) functions, such as mobility, authentication, and bearer management for UEs (115) served by base stations (105) associated with the EPC. User IP packets may be transmitted through the S-GW, and the S-GW itself may be connected to the P-GW. The P-GW may provide IP address allocation as well as other functions. The P-GW may be connected to network operator IP services. Operator IP services may include access to the Internet, intranet(s), IP multimedia subsystem (IMS), or packet switching (PS) streaming services.

[0090] At least some of the network devices, such as the base station (105), may include subcomponents, such as an access network entity, which may be an example of an access node controller (ANC). Each access network entity may communicate with UEs (115) through a number of other access network transmitting entities, and the number of other access network transmitting entities may be referred to as radio heads, smart radio heads, or transmit / receive points (TRPs). In some configurations, the various functions of each access network entity or base station (105) may be distributed across various network devices (e.g., radio heads and access network controllers) or integrated into a single network device (e.g., base station (105)).

[0091] A wireless communication system (100) may typically operate using one or more frequency bands in the range of 300 megahertz (MHz) to 300 gigahertz (GHz). Generally, the range from 300 MHz to 3 GHz is known as the ultra-high frequency (UHF) region or decimeter band because the wavelengths range in length from approximately 1 decimeter to 1 meter. UHF waves may be blocked or redirected by buildings and environmental features. However, the waves may penetrate structures sufficiently to provide service to UEs (115) located indoors by macro cells. Transmission of UHF waves may be associated with smaller antennas and shorter ranges (e.g., less than 100 km) compared to transmission using smaller frequencies and longer waves in the high frequency (HF) or very high frequency (VHF) portions of the spectrum below 300 MHz.

[0092] The wireless communication system (100) may also operate in the super high frequency (SHF) range using frequency bands from 3 GHz to 30 GHz, which are also known as centimeter bands. The SHF range includes bands such as the 5 GHz industrial, scientific, and medical (ISM) bands, which may be used opportunistically by devices that may be able to withstand interference from other users.

[0093] The wireless communication system (100) may also operate in the extreme high frequency (EHF) region of the spectrum (e.g., from 30 GHz to 300 GHz), which is also known as the millimeter band. In some examples, the wireless communication system (100) may support millimeter wave (mmW) communication between UEs (115) and base stations (105), and the EHF antennas of individual devices may be much smaller and more closely spaced than UHF antennas. In some cases, this may facilitate the use of antenna arrays within the UE (115). However, the propagation of EHF transmitters may undergo much greater atmospheric attenuation and a shorter range than that of SHF or UHF transmitters. The techniques disclosed herein may be employed across transmitters using one or more different frequency regions, and the designated use of bands across these frequency regions may vary by country or regulatory body.

[0094] In some cases, the wireless communication system (100) may utilize both licensed and unlicensed radio frequency spectrum bands. For example, the wireless communication system (100) may employ Licensed Assisted Access (LAA), LTE Unlicensed (LTE-U) radio access technology, or NR technology in an unlicensed band such as the 5 GHz ISM band. When operating in unlicensed radio frequency spectrum bands, wireless devices such as base stations (105) and UEs (115) may employ listen-before-talk (LBT) procedures to ensure that the frequency channel is clear before transmitting data. In some cases, operations in unlicensed bands may be based on carrier aggregation configurations with component carriers operating in licensed bands (e.g., LAA). Operations in the unlicensed spectrum may include downlink transmissions, uplink transmissions, peer-to-peer transmissions, or a combination thereof. Duplexing in the unpermitted spectrum may be based on frequency division duplexing (FDD), time division duplexing (TDD), or a combination of both.

[0095] In some examples, the base station (105) or the UE (115) may be equipped with multiple antennas, and these multiple antennas may be used to employ techniques such as transmit diversity, receive diversity, multiple input multiple output (MIMO) communication, or beamforming. For example, a wireless communication system (100) may use a transmission method between a transmitting device (e.g., base station (105)) and a receiving device (e.g., UE (115)), wherein the transmitting device is equipped with multiple antennas and the receiving device is equipped with one or more antennas. MIMO communication may employ multipath signal propagation to increase spectral efficiency by transmitting or receiving multiple signals through different spatial layers, which may be referred to as spatial multiplexing. Multiple signals may be transmitted by the transmitting device, for example, through different antennas or different combinations of antennas. Likewise, multiple signals may be received by the receiving device through different antennas or different combinations of antennas. Each of the multiple signals may be referred to as a separate spatial stream and may carry bits associated with the same data stream (e.g., the same codeword) or different data streams. Different spatial layers may be associated with different antenna ports used for channel measurement and reporting. MIMO techniques include single-user MIMO (SU-MIMO), where multiple spatial layers are transmitted to the same receiving device, and multi-user MIMO (MU-MIMO), where multiple spatial layers are transmitted to multiple devices.

[0096] Beamforming, which may also be referred to as spatial filtering, directional transmission, or directional reception, is a signal processing technique that may be used at a transmitting device or a receiving device (e.g., base station (105) or UE (115)) to shape or steer an antenna beam (e.g., a transmitting beam or a receiving beam) along a spatial path between a transmitting device and a receiving device. Beamforming may be achieved by combining signals communicated through antenna elements of an antenna array such that signals propagating toward specific orientations with respect to the antenna array experience constructive interference, while other signals experience destructive interference. The adjustment of signals communicated through antenna elements may include the transmitting device or the receiving device applying specific amplitude and phase offsets to the signals carried through each of the antenna elements associated with the device. The adjustments associated with each of the antenna elements may be defined by a set of beamforming weights associated with a specific orientation (e.g., for the antenna array of the transmitting device or the receiving device or for some other orientation).

[0097] In one example, the base station (105) may use multiple antennas or antenna arrays to perform beamforming operations for directional communication with the UE (115). For example, some signals (e.g., synchronization signals, reference signals, beam select signals, or other control signals) may be transmitted multiple times by the base station (105) in different directions, which may include signals transmitted according to different beamforming weight sets associated with different directions of transmission. Transmitters to different beam directions may be used to identify the beam direction for subsequent transmission and / or reception by the base station (105) (e.g., by a receiving device such as the base station (105) or the UE (115).

[0098] Some signals, such as data signals associated with a specific receiving device, may be transmitted by the base station (105) in a single beam direction (e.g., a direction associated with a receiving device such as the UE (115)). In some examples, the beam direction associated with the transmissions along the single beam direction may be determined at least partially based on signals transmitted in different beam directions. For example, the UE (115) may receive one or more of the signals transmitted by the base station (105) in different directions, and the UE (115) may report to the base station (105) an indication of the received signal with the highest signal quality or otherwise acceptable signal quality. Although these techniques are described with reference to signals transmitted in one or more directions by the base station (105), the UE (115) may employ similar techniques for transmitting signals multiple times in different directions (e.g., to identify the beam direction for subsequent transmission or reception by the UE (115)) or for transmitting a signal in a single direction (e.g., to transmit data to a receiving device).

[0099] A receiving device (e.g., a UE (115) which may be an example of a mmW receiving device) may attempt multiple receiving beams when receiving various signals from a base station (105), such as synchronization signals, reference signals, beam select signals, or other control signals. For example, the receiving device may attempt multiple receiving directions by receiving through different antenna subarrays, by processing signals received according to different antenna subarrays, by receiving according to different sets of receiving beamforming weights applied to signals received from multiple antenna elements of an antenna array, or by processing signals received according to different sets of receiving beamforming weights applied to signals received from multiple antenna elements of an antenna array, any of which may be referred to as "listening" according to different receiving beams or receiving directions. In some examples, the receiving device may use a single receiving beam to receive along a single beam direction (e.g., when receiving a data signal). A single receiving beam may be aligned to a beam direction determined at least partially based on listening according to different receiving beam directions (e.g., a beam direction determined to have the highest signal strength, highest signal-to-noise ratio, or otherwise acceptable signal quality based at least partially based on listening according to multiple beam directions).

[0100] In some cases, the antennas of the base station (105) or the UE (115) may be located within one or more antenna arrays that may support MIMO operations or transmit or receive beamforming. For example, one or more base station antennas or antenna arrays may be placed in an antenna assembly such as an antenna tower. In some cases, the antennas or antenna arrays associated with the base station (105) may be located at various geographical locations. The base station (105) may have an antenna array having multiple rows and columns of antenna ports that the base station (105) may use to support beamforming for communication with the UE (115). Likewise, the UE (115) may have one or more antenna arrays that may support various MIMO or beamforming operations.

[0101] In some cases, the wireless communication system (100) may be a packet-based network operating according to a layered protocol stack. In the user plane, communication at the bearer or Packet Data Convergence Protocol (PDCP) layer may be IP-based. The Wireless Link Control (RLC) layer may communicate over logical channels by performing packet segmentation and reassembly. The Media Access Control (MAC) layer may perform priority handling and multiplexing of logical channels into transport channels. The MAC layer may also improve link efficiency by using Hybrid Automatic Repeat Request (HARQ) to provide retransmission at the MAC layer. In the control plane, the Wireless Resource Control (RRC) protocol layer may provide the establishment, configuration, and maintenance of RRC connections between the core network (130) or base station (105) supporting wireless bearers for user plane data and the UE (115). In the physical layer, transport channels may be mapped to physical channels.

[0102] In some cases, UEs (115) and base stations (105) may support data retransmissions to increase the likelihood that data will be successfully received. HARQ feedback is a technique that increases the likelihood that data will be accurately received over a communication link (125). HARQ may include a combination of error detection (e.g., using Cyclic Redundancy Check (CRC)), Forward Error Correction (FEC), and retransmission (e.g., Automatic Repetition Request (ARQ)). HARQ may improve throughput at the MAC layer under poor radio conditions (e.g., signal-to-noise conditions). In some cases, the radio device may support same-slot HARQ feedback, where the device may provide HARQ feedback in a specific slot for data received in a previous symbol within the slot. In other cases, the device may provide HARQ feedback in a subsequent slot or according to some other time interval.

[0103] Time intervals in LTE or NR are the basic time unit (this is, for example, the sampling period T). s It can also be expressed as a multiple of (which may refer to 1 / 30,720,000 seconds). The time intervals of communication resources may be organized according to radio frames each having a duration of 10 milliseconds (ms), where the frame period is T f = 307,200 T sIt may also be represented as. Wireless frames may be identified by a system frame number (SFN) ranging from 0 to 1023. Each frame may contain 10 subframes numbered from 0 to 9, and each subframe may have a duration of 1 ms. Subframes may be further divided into two slots each having a duration of 0.5 ms, and each slot may contain 6 or 7 modulation symbol periods (e.g., depending on the length of the cyclic prefix pre-defended for each symbol period). Excluding the cyclic prefix, each symbol period may contain 2048 sampling periods. In some cases, a subframe may be the minimum scheduling unit of the wireless communication system (100) and may be referred to as a transmit time interval (TTI). In other cases, the minimum scheduling unit of the wireless communication system (100) may be shorter than a subframe, or may be dynamically selected (e.g., in bursts of shortened TTIs (sTTIs) or in selected component carriers using sTTIs).

[0104] In some wireless communication systems, a slot may additionally be divided into multiple mini-slots containing one or more symbols. In some cases, a symbol or mini-slot of a mini-slot may be the minimum unit of scheduling. Each symbol may vary in duration depending, for example, on subcarrier spacing or the frequency band of operation. Additionally, some wireless communication systems may implement slot aggregation in which multiple slots or mini-slots are aggregated together and used for communication between the UE (115) and the base station (105).

[0105] The term “carrier” refers to a set of radio frequency spectrum resources having a defined physical layer structure to support communication over a communication link (125). For example, a carrier of a communication link (125) may include a portion of a radio frequency spectrum band that operates according to physical layer channels for a given radio access technology. Each physical layer channel may carry user data, control information, or other signaling. A carrier may be associated with a predefined frequency channel (e.g., an Advanced Universal Mobile Telecommunications System Terrestrial Radio Access (E-UTRA) Absolute Radio Frequency Channel Number (EARFCN)) and may be positioned according to a channel raster for discovery by UEs (115). Carriers may be downlink or uplink (e.g., in FDD mode) or may be configured to carry downlink and uplink communications (e.g., in TDD mode). In some examples, signal waveforms transmitted over a carrier may be composed of multiple subcarriers (using multi-carrier modulation (MCM) techniques such as orthogonal frequency division multiplexing (OFDM) or discrete Fourier transform spread OFDM (DFT-S-OFDM).

[0106] The organizational structure of carriers may differ for different wireless access technologies (e.g., LTE, LTE-A, LTE-A Pro, NR). For example, communication over a carrier may be organized according to TTIs or slots, each of which may include user data as well as control information or signaling to support decoding user data. A carrier may also include dedicated capture signaling (e.g., synchronization signals or system information, etc.) and control signaling to coordinate operations for the carrier. In some examples (e.g., in a carrier aggregation configuration), a carrier may also have control signaling or capture signaling to coordinate operations for other carriers.

[0107] Physical channels may be multiplexed over a carrier according to various techniques. Physical control channels and physical data channels may be multiplexed over a downlink carrier using, for example, time division multiplexing (TDM) techniques, frequency division multiplexing (FDM) techniques, or hybrid TDM-FDM techniques. In some examples, control information transmitted in a physical control channel may be distributed in a cascaded manner between different control regions (e.g., between a common control region or common search space and one or more UE-specific control regions or UE-specific search spaces).

[0108] A carrier may be associated with a specific bandwidth of the radio frequency spectrum, and in some examples, the carrier bandwidth may be referred to as the "system bandwidth" of the carrier or the wireless communication system (100). For example, the carrier bandwidth may be one of a number of predetermined bandwidths (e.g., 1.4, 3, 5, 10, 15, 20, 40, or 80 MHz) for carriers of a particular wireless access technology. In some examples, each served UE (115) may be configured to operate on a portion or the whole of the carrier bandwidth. In other examples, some UEs (115) may be configured to operate using a narrowband protocol type associated with a predetermined portion or range (e.g., a set of subcarriers or RBs) within the carrier (e.g., an "in-band" deployment of the narrowband protocol type).

[0109] In a system employing MCM techniques, a resource element may consist of one symbol period (e.g., the duration of one modulated symbol) and one subcarrier, wherein the symbol period and subcarrier spacing are inversely related. The number of bits carried by each resource element may depend on the modulation scheme (e.g., the order of the modulation scheme). Thus, the more resource elements the UE (115) receives and the higher the order of the modulation scheme, the higher the data rate for the UE (115). In MIMO systems, radio communication resources may refer to a combination of radio frequency spectrum resources, time resources, and spatial resources (e.g., spatial layers), and the use of multiple spatial layers may further increase the data rate for communication with the UE (115).

[0110] Devices of the wireless communication system (100) (e.g., base stations (105) or UEs (115)) may have a hardware configuration that supports communication over a specific carrier bandwidth, or may be configured to support communication over one of a set of carrier bandwidths. In some examples, the wireless communication system (100) may include base stations (105) and / or UEs (115) that support simultaneous communication over carriers associated with more than one different carrier bandwidth.

[0111] The wireless communication system (100) may support communication with the UE (115) over multiple cells or carriers, and this feature may be referred to as carrier aggregation or multi-carrier operation. The UE (115) may be composed of multiple downlink component carriers and one or more uplink component carriers according to the carrier aggregation configuration. Carrier aggregation may be used with both FDD and TDD component carriers.

[0112] In some cases, the wireless communication system (100) may utilize enhanced component carriers (eCCs). The eCC may be characterized by one or more features including a wider carrier or frequency channel bandwidth, a shorter symbol duration, a shorter TTI duration, or a modified control channel configuration. In some cases, the eCC may be associated with a carrier aggregation configuration or a duplex configuration (e.g., when multiple serving cells have suboptimal or non-ideal backhaul links). The eCC may also be configured for use in unlicensed spectrum or shared spectrum (e.g., where more than one operator is allowed to use the spectrum). An eCC characterized by a wide carrier bandwidth may include one or more segments that may be utilized by UEs (115) that are not able to monitor the entire carrier bandwidth or otherwise are configured to use a limited carrier bandwidth (e.g., to conserve power).

[0113] In some cases, eCC may utilize a symbol duration different from that of other component carriers, which may involve the use of a reduced symbol duration compared to the symbol durations of other component carriers. A shorter symbol duration may be associated with increased spacing between adjacent subcarriers. A device such as a UE (115) or base station (105) utilizing eCCs may transmit broadband signals at reduced symbol durations (e.g., 16.67 microseconds) (e.g., depending on frequency channels or carrier bandwidths such as 20, 40, 60, 80 MHz). TTI in eCC may consist of one or multiple symbol periods. In some cases, the TTI duration (i.e., the number of symbol periods in TTI) may be variable.

[0114] The wireless communication system (100) may be an NR system that, among other things, may utilize any combination of licensed, shared, and unlicensed spectrum bands. Flexibility in eCC symbol duration and subcarrier spacing may allow the use of eCC across multiple spectra. In some examples, the NR shared spectrum may increase spectrum utilization and spectrum efficiency, particularly through dynamic vertical sharing of resources (e.g., across the frequency domain) and horizontal sharing (e.g., across the time domain).

[0115] In some cases, the wireless communication system (100) may be an example of a wireless backhaul communication network, such as an IAB network. The IAB network may include an IAB donor (or anchor) node and one or more relay nodes downstream from the donor node. In some embodiments, the IAB network shares resources between access and backhaul links so that access traffic may be relayed over the wireless backhaul. In some cases, the same technology may be used for the access links and backhaul links. IAB donor nodes may provide access and wireless backhaul functionality to the IAB nodes for child UEs. The IAB donor may include a CU for controlling the IAB network and one or more DUs for scheduling child IAB nodes. The IAB donor may have a wired connection to the core network (130). Downstream from an IAB donor node may include one or more IAB nodes within an IAB network (also referred to as parent nodes, relay nodes, or child nodes depending on where the node is located within the IAB network), each of which wirelessly relays traffic from its child nodes (e.g., UEs, or other IAB nodes) to a parent node (e.g., an IAB donor or IAB node). A UE (115) may wirelessly connect to a donor or IAB node within the range of the UE (115). In some cases, a base station (105) may be an example of an IAB node.

[0116] Wireless communication systems described herein, such as the wireless communication system (100), may support network coding operations at intermediate nodes. For example, an intermediate node may receive unencoded or raw data packets and perform network coding, such as fountain coding, to generate encoded packets. Then, the intermediate node may distribute packet segments among a set of paths to a receiving UE (115). Encoding at an intermediate node and transmitting packet segments using a set of paths may be robust against blocking or congestion at a specific node and may establish clear endpoints (e.g., receiver and transmitter) for the encoded packets.

[0117] In some cases, the intermediate node may perform network decoding to reduce feedback latency. For example, the IAB intermediate node may decode received packet segments (e.g., fountain-coded packets) and report whether the decoding was successful to prompt retransmission by the transmitter. This may improve the rate of feedback provided, as the IAB intermediate node may send feedback instead of transmitting packets to the IAB access node over one or more hops, and as the IAB access node is solely responsible for providing feedback. Additionally, the IAB intermediate node may perform network decoding on received encoded packets and then transmit the decoded packets to other (e.g., downstream) nodes. For example, the IAB intermediate node may decode multiple encoded packets and transmit one or more decoded packets over a first wireless link and one or more other decoded packets over a second wireless link. In some examples, an IAB intermediate node may transmit packets along one or more paths through wireless links, and the packets may contain the same path identifier or different path identifiers.

[0118] FIG. 2 illustrates an example of a wireless communication system (200) that supports reducing feedback latency for network coding in wireless backhaul communication networks according to embodiments of the present disclosure. The wireless communication system (200) (e.g., NR system, mmW system, etc.) may supplement wired backhaul connections (e.g., wired backhaul links (220)) by providing an IAB network architecture by sharing wireless backhaul link capabilities and infrastructure and spectrum resources for network access. The wireless communication system (200) may include a core network (205) and base stations (105) or supported devices that are divided into one or more supporting entities (i.e., functionalities) to promote wireless backhaul density in cooperation with communication access. Aspects of the supporting functionalities of the base stations (105) may be referred to as IAB nodes, such as IAB donor nodes (210) and IAB repeater nodes (215). The wireless communication system (200) may additionally support one or more IAB donor nodes (210), IAB repeater nodes (215), or a combination of these devices and a plurality of UEs (115) that may communicate on the uplink. In some examples, the wireless communication system (200) may implement aspects of the wireless communication system (100).

[0119] The wireless communication system (200) may include one or more IAB donor nodes (210) that may interface between a wired network and a wireless network. In some cases, the IAB donor node (210) may be referred to as an anchor node because the IAB donor node (210) anchors the wireless network to the wired connection. For example, each IAB donor node (210) may include at least one wired backhaul link (220) and one or more additional links (e.g., wireless backhaul links (225), backup wireless backhaul links (230), access links (235), etc.). The IAB donor node (210) may be divided into associated base station central unit (CU) and distributed unit (DU) entities, wherein one or more DUs associated with the IAB donor node (210) may be partially controlled by the associated CU. The CUs of the IAB donor nodes (210) may host Layer 3 (L3) functionality and signaling (e.g., RRC, Service Data Adaptation Protocol (SDAP), PDCP, etc.). Additionally, the CUs of the IAB donor nodes (210) may communicate with the core network (205) over a wired backhaul link (220) (e.g., which may be referred to as an NG interface). The DUs may host lower-layer operations such as Layer 1 (L1) or Layer 2 (L2) functionality and signaling (e.g., RLC, MAC, physical layer, etc.). The DU entities of the IAB donor nodes (210) may support serving cells within the network coverage area according to connections associated with the wireless backhaul links (225) and access links (235) of the IAB network.The DUs of the IAB donor nodes (210) may control both access and backhaul links within the corresponding network coverage, and may also provide control and scheduling for descendant (i.e., child) IAB repeater nodes (215) and / or UEs (115). For example, the DU may support RLC channel access with the UE (115) (e.g., via an access link (235)) or with the IAB repeater node (215) (e.g., via a backhaul link such as a primary wireless backhaul link (225) or a backup wireless backhaul link (230).

[0120] IAB repeater nodes (215) may be divided into associated mobile terminals (MT) and base station DU entities, wherein the MT functionality of the IAB repeater nodes (215) may be controlled or scheduled by ancestor (i.e., parent) IAB nodes via wireless backhaul links. The parent node for an IAB repeater node (215) may be another (ancestor) IAB repeater node (215) or a donor node (210). The MT functionality may be similar to the functionality performed by UEs (115) in the system. The IAB repeater node (215) may not be directly connected to the wired backhaul (220). Alternatively, the IAB repeater node (215) may connect to the core network (205) via other IAB nodes (e.g., any number of additional IAB repeater nodes (215) and IAB donor nodes (210)) using wireless backhaul links. The IAB repeater node (215) may also transmit upstream from the IAB system (e.g., toward the core network (205)) using MT functionality. In some cases, the DUs of the IAB repeater nodes (215) may be partially controlled by signaling messages from the CU entities of the associated IAB donor node (210) (e.g., transmitted via the F1-Application Protocol (AP)). The DUs of the IAB repeater nodes (215) may support serving cells in the network coverage area. For example, the DU of the IAB repeater node (215) may perform the same or similar functions as the DU of the IAB donor node (210), which supports one or more access links (235) to UEs (115), one or more wireless backhaul links to downstream IAB repeater nodes (215), or both of these.

[0121] A wireless communication system (200) may employ repeater chains for communications within an IAB network architecture. For example, a UE (115) may communicate with an IAB node, and the IAB node may relay data to a base station CU or core network (205) directly or through one or more IAB repeater nodes (215). Each IAB repeater node (215) may include a primary wireless backhaul link (225) for receiving information from the base station CU or core network (205) or relaying data upstream. In some cases, an IAB repeater node (215) may additionally include one or more backup wireless backhaul links (230) (e.g., for redundant connectivity or improved robustness). If the primary wireless backhaul link (225) fails (e.g., due to interference, malfunction at a connected IAB node, movement of IAB nodes, maintenance at IAB nodes, etc.), the IAB repeater node (215) may utilize the backup wireless backhaul link (230) for backhaul communication within the IAB network. The first (e.g., primary) wireless backhaul link (225) may be associated with a coverage area, and MT functionality may be controlled or scheduled by the first parent node. One or more secondary backhaul links (e.g., backup wireless backhaul links (230)) may be associated with non-juxtended coverage areas and may be controlled or scheduled by one or more parent nodes. Each of the primary backhaul connections and one or more secondary connections may support spectrum capabilities to provide network communication over one or more RATs. One or more IAB nodes may additionally support base station DU entities and may support multiple backhaul and access links within the repeater chain.DU entities may control or schedule descendant IAB relay nodes (215) and UEs (115) within the IAB network (e.g., downstream of the IAB network) through configured backhaul and access links. That is, the IAB relay node (215) may act as a relay between the IAB donor node (210) and one or more descendant devices (e.g., other IAB relay nodes (215), UEs (115), etc.) in the communication directions of both based on established backhaul and access connections.

[0122] In some cases, the wireless communication system (200) may support network coding operations such as fountain coding. Fountain coding may be used to improve the robustness of packet transmissions. An example of fountain coding is described in more detail with reference to FIG. 3. In some conventional systems, fountain coding may be performed by network coding layers at the IAB access node (e.g., directly serving the UE (115)) and at the IAB donor node (210), but may not be performed at IAB intermediate nodes (e.g., between the IAB access node and the IAB donor node (210)). Restricting network coding to be performed by the IAB access node and the IAB donor node (210) may degrade network performance, examples of which are described in more detail in FIG. 5.

[0123] Wireless communication systems (200), and other wireless communication systems implementing the techniques described herein, may support network coding at intermediate nodes. For example, an intermediate node may receive unencoded packets (e.g., RLC packet data units (PDUs)) and perform network coding (e.g., Fountain coding) to generate encoded packets. Then, the intermediate node may distribute packet segments among a set of paths to a receiving UE (115). Encoding at an intermediate node and transmitting packet segments using a set of paths may be robust against blocking or congestion at a specific node, as in the examples described with reference to FIG. 4.

[0124] In another example, the intermediate node may perform network decoding to reduce feedback latency. For example, the IAB intermediate node may decode received packet segments (e.g., fountain-coded packets) and report whether the decoding was successful to prompt retransmission by the transmitter. This may improve the rate of feedback provided, as the IAB intermediate node may send feedback instead of transmitting packets to the IAB access node over one or more hops, and as the IAB access node is solely responsible for providing feedback. Additionally, the IAB intermediate node may perform network decoding on received encoded packets and then transmit the decoded packets to other (e.g., downstream) nodes. For example, the IAB intermediate node may decode multiple encoded packets and transmit one or more decoded packets over a first wireless link and one or more other decoded packets over a second wireless link. In some examples, the IAB intermediate node may transmit packets along one or more paths through the first and / or second wireless links, and each packet may include a path identifier for the corresponding path.

[0125] FIG. 3 illustrates an example of a coding procedure (300) that supports reducing feedback latency for network coding in wireless backhaul communication networks according to embodiments of the present disclosure. In some embodiments, the coding procedure (300) may implement embodiments of a wireless communication system (100). The coding procedure (300) may be an example of fountain coding or other types of network coding. In some cases, the coding procedure (300) may be performed at a network coding layer in an IAB node, such as an IAB donor node (210) or an IAB repeater node (215) described with reference to FIG. 2.

[0126] The transmitting device may have K packets to transmit. In some cases, each packet may be a data segment for a receiver such as a UE (115) or may return data. Each of the K packets may contain data, may be referred to as packets returning raw data or raw packets. In some cases, the packets at the transmitter may be RLC PDUs.

[0127] The transmitting device may perform a network coding procedure to encode packets, for example, by performing fountain encoding. The transmitting device may transmit a stream of encoded packets to a receiver, where each encoded packet may be generated from a subset of K raw packets. In some cases, the encoded packets may be referred to as packet segments. After receiving a new encoded packet, the receiver may attempt to receive or decode the K raw packets. The receiver may transmit a stop or acknowledgment (e.g., acknowledgment (ACK) / negative acknowledgment (NACK) feedback) when decoding the K packets. In some cases, the number of encoded packets (e.g., N encoded packets) may not be determined in advance. For example, the transmitter may generate packets using the K packets until the reception of an acknowledgment or stop indicator. In some cases, information regarding the encoded symbols may be shared with the receiver to enable decoding. For example, data from K packets may be encoded into packets or packet segments according to a known pattern or configuration. Then, the receiver may know which raw data packets are in the first encoded packet, the second encoded packet, etc.

[0128] In the example of the coding procedure (300), the transmitter may have three raw packets (e.g., P1 (305-a), P2 (305-b), and P3 (305-c)). The transmitter may transmit a first encoded packet (310-a) to a receiver. The first encoded packet (310-a) may contain data for P2 (305-b). Upon receiving the first encoded packet (310-a), the receiver may have data for P2 (305-b).

[0129] The transmitter may send a second encoded packet (310-b) to the receiver. The second encoded packet (310-b) may contain or be based on data for P1 (305-a) and P2 (305-b). However, the receiver may not receive the second encoded packet (310-b). For example, there may be interference, blocking, or congestion nodes between devices on the channel returning the second encoded packet (310-b). In some examples, the receiver may still monitor for new packets despite the failed reception of the second encoded packet (310-b) (e.g., without sending a NACK).

[0130] The transmitter may transmit a third encoded packet (310-c) to the receiver. The third encoded packet (310-c) may contain data for P1 (305-a) and P3 (305-c). Upon receiving the third encoded packet (310-c), the receiver may not be able to derive information from the third encoded packet (310-c) because the receiver may only have data for P2 (305-b) from the first packet (310-a). The transmitter may transmit a fourth encoded packet (310-d) containing data for P2 (305-b) and P3 (305-c). The receiver may successfully receive the fourth encoded packet (310-d).

[0131] The receiver may determine data for P3 (305-c) based on the first encoded packet (310-a) and the fourth encoded packet (310-d). For example, the receiver may decode P3 (305-c) by removing the value of P2 (305-b) from the fourth encoded packet (310-d) to leave only the data for P3 (305-c). Once the receiver has the data for P3 (305-c), the receiver may decode P1 (305-a) from the third encoded packet (310-c). Thus, even though the second encoded packet (310-b) is not successfully received, the receiver may still successfully decode K packets (305).

[0132] In the example of the coding procedure (300), four encoded packets may be transmitted before three original packets are decoded. Then, the receiver may send an acknowledgment to the transmitter. In this example, the rate may be 3 / 4 (e.g., three raw data packets transmitted as four encoded packets). The rate may be variable based on how many encoded packets the transmitter sends before receiving the acknowledgment.

[0133] In some cases, after decoding the encoded packets, the receiving device may transmit one or more of the decoded packets to one or more (e.g., downstream) devices. For example, the receiving device may decode a first encoded packet and transmit the first decoded packet over a first wireless link and along a first path (e.g., among a plurality of paths). The first decoded packet may include a path identifier for the first path. Similarly, the receiving device may decode a second encoded packet and transmit the second decoded packet over a second wireless link and along a second path (e.g., among a plurality of paths). The second decoded packet may include a path identifier for the second path. In some examples, the first and second wireless links may be the same, but the first path may be different from the second path. In some examples, the first and second wireless links may be different, and the first path may be different from the second path.

[0134] FIG. 4 illustrates an example of a transmission path configuration (400) that supports reducing feedback latency for network coding in wireless backhaul communication networks according to embodiments of the present disclosure. In some embodiments, the transmission path configuration (400) may implement embodiments of a wireless communication system (100).

[0135] The transmitter (405) may utilize spatial diversity in the network by transmitting encoded packets to the receiver (410) over different paths (420). The path (420) may include one or more hops of intermediate nodes (415). In some cases, the transmitter (405) may be an example of an IAB node, such as an IAB donor node or an IAB repeater node as described with reference to FIG. 2. The receiver (410) may be an example of a UE (115), an IAB access node, or an IAB repeater node. The intermediate node (415) may be an example of an IAB node, such as an IAB repeater node.

[0136] In some cases, transmitting encoded packets over different paths (420) may improve the robustness of the wireless communication system. For example, the wireless communication system may adapt to packets lost due to link failures or temporary link interruptions. These techniques may also enable the wireless communication system to adapt to packets lost due to congestion at intermediate nodes. In some cases, the order of arrival of encoded symbols at the receiver (410) may not matter. In some examples, the total count of raw packets and encoded packets (e.g., corresponding to the rate) may be determined.

[0137] In some cases, the receiver (410) may provide a common acknowledgment for K decoded original packets on an end-to-end basis. For example, once the receiver (410) receives a complete set of original packets of a data transmission, the receiver (410) may provide feedback (e.g., ACK) on the original packets. Without an ACK, the transmitter (405) may continue to generate and transmit encoded packets between different paths. In some cases, a common ACK for the packets may improve latency between the receiver (410) and the transmitter (405). In some cases, a common ACK may reduce signaling overhead and network energy consumption. In some examples, the receiver (410) may transmit a NACK if some packets are not received (e.g., after a threshold of the cycle time).

[0138] In the example of a transmission path configuration (400), there may be three different paths (420) between the transmitter (405) and the receiver (410). For example, the first path (420-a) may have three intermediate nodes (415), and one of the intermediate nodes (415) may be a congested node (425). The congested node (425) may cause transmission delays or failures along the first path (420-a). The second path (420-b) may also have three intermediate nodes (415) (e.g., and a common first hop to the intermediate node for the first path (420-a)), but the second path (420-b) may not use the congested node (425). The third path (420-b) may have two intermediate nodes (415), but there may be a block (430) between the two intermediate nodes (415). The block (430) may cause delays or transmission failures on the third path (420-c).

[0139] Throughput between the transmitter (405) and the receiver (410) may be improved by utilizing spatial transmission diversity and transmitting encoded packet segments on each of the three paths (420). For example, if signaling were transmitted only on the first path (420-a) or the third path (420-c), congestion nodes (425) and blocking (430) could significantly increase latency or cause major transmission failures. By utilizing all three paths, the transmitter (405) may still transmit some signaling to the receiver (410). Then, by utilizing coding techniques (e.g., fountain coding as described with reference to FIG. 3), the receiver (410) may decode data transmissions from the transmitter (405) even if the receiver (410) does not successfully receive each encoded packet.

[0140] FIG. 5 illustrates an example of a protocol stack (500) that supports reducing feedback latency for network coding in wireless backhaul communication networks according to embodiments of the present disclosure. In some embodiments, the protocol stack (500) may implement embodiments of a wireless communication system (100).

[0141] The protocol stack (500) may represent the protocol stacks and network functionalities of multiple devices. For example, the protocol stack (500) may represent different protocol stacks and layers for the UE (115). The protocol stack (500) may also represent different protocol stacks and layers for IAB nodes, such as IAB donor nodes, IAB repeater nodes, and IAB access nodes. For some IAB nodes, the protocol stacks may be split between the DU and MT or between the DU and CU.

[0142] The protocol stack (500) may represent how different entities in different devices interact when a transmission is transmitted from a transmitter (e.g., an IAB donor node) to a receiver (e.g., a UE (115)) in an IAB network, which may include a transmission transmitted over one or more intermediate nodes. The protocol stack (500) may include a UE (115), an IAB node (510) and an IAB node (515), an IAB donor DU (520), an IAB donor CU (525), and a user plane function (UPF) (530).

[0143] Wireless communication systems implementing the techniques described herein may support network coding. Network coding may be transparent to the UE (115), so that the UE (115) may not be aware of network coding or where network coding is occurring. Some systems may have a network coding layer (NCL) (e.g., NCL (505)) on top of the backhaul adaptation protocol (BAP) layer between the IAB donor DU (520) and the access IAB node MT (e.g., of the IAB node (510)). The BAP layer may perform routing and bearer mapping. The BAP may be an IAB node configurable by mapping from a BAP routing identifier to an outgoing link. In some cases, the BAP may be an IAB node configurable by mapping from an incoming RLC channel to an outgoing RLC channel. The BAP routing identifier returned in the BAP header may include a BAP address (e.g., for an IAB node or an IAB donor DU) and a BAP path identifier. The BAP path identifier may indicate the path followed by the packet flow. The destination IAB node or IAB donor DU address or path identifier may be unique within the IAB donor CU. In some cases, the BAP address of the IAB node may be used to distinguish traffic to be delivered to upper layers from traffic to be delivered to outflow RLC channels. For example, the IAB node may receive data packets, check the BAP header for the data packets, and determine whether to transmit the data to upper layers, whether to perform network encoding or decoding, or whether to transmit the data packets along the path indicated by the BAP information.

[0144] As described in this specification, the NCL (505) in the IAB donor DU (520) may encode K IP packets into N segments. The encoded segments may be assigned different BAP path identifiers and thus may traverse different paths between the donor DU and the access IAB node (e.g., as routed by the BAP layer). The receiver may restore the original packets when enough encoded packets are collected so that the receiver can decode or reassemble the original packets. The reassembled packets may be delivered to the upper layers in the access IAB node and may be transmitted to the UE (115) (e.g., over the PHY and RLC layers).

[0145] In some conventional systems, only the MT and IAB donor DU (520) of the access IAB node (510) may use the NCL (505) to encode or decode encoded packet segments. However, these conventional techniques may not operate across multiple data paths to a UE (115) having different donor DUs. Additionally, conventional techniques may not operate across cell groups for a multi-access UE (115) (e.g., having multiple access IAB nodes). End-to-end feedback in these systems may significantly increase latency for a long chain of intermediate nodes between the access IAB node and the donor IAB DU.

[0146] To improve latency and robustness, intermediate nodes (e.g., intermediate IAB node (515)) may also use NCL (505) to encode or decode packet segments. The NCL (505) at the intermediate node (515) may also be located above the BAP layer. In some cases, the NCL (505) at the intermediate node (515) may be enabled or disabled. For example, in some cases, network coding and decoding may be integrated into the BAP layer of the intermediate node (515). By utilizing the NCL (505) at the intermediate IAB node (515), the intermediate IAB node (515) may enable network coding for multiple data paths to UEs (115) using different donor DUs. An example of network coding having multiple data paths from different donor DUs to the UE (115) is described in more detail with reference to the wireless communication system (600) of FIG. 6. Additionally, utilizing the NCL (505) at the intermediate IAB node (515) may reduce feedback latency and improve the code rate.

[0147] For a specific flow of RLC PDUs (e.g., from a donor IAB node to a UE (115)), an NCL (505) (e.g., a linear network coder / decoder or a fountain coder / decoder) may be used in multiple devices. For example, there may be bearers between the NCLs (505) of an access IAB node MT and an IAB donor DU, an access IAB node MT and an intermediate IAB node DU, and an intermediate IAB node MT and an IAB donor DU.

[0148] In the first example, network coding may be enabled for a set of RLC PDUs at the intermediate node (515). The intermediate IAB node (515) may receive raw RLC PDUs on an incoming link or RLC channel and encode the PDUs (e.g., packet segments) using linear network coding or fountain coding operations. The intermediate IAB node (515) may transmit the encoded PDUs on one or more outgoing links or RLC channels. The encoded segments may be associated with different BAP path identifiers. In some cases, the encoded segments may be assigned non-uniformly different BAP path identifiers as configured by the CU of the IAB donor node. The BAP layer may route the packet segments to different paths as described with reference to FIG. 3. The intermediate IAB node (515) may receive feedback based on the transmitted PDUs. In this first example, network coding may occur at an intermediate node (515) instead of an IAB donor DU (520). Alternatively, the IAB donor DU (520) may transmit RLC PDUs directly to the intermediate IAB node (515). The first example may, in some cases, increase the robustness of the communication link between the IAB donor node and the UE (115) and support communications on multiple paths from different IAB donor nodes to the UE (115) based on the intermediate IAB node (515) performing network coding (e.g., instead of different IAB donor nodes performing coding).

[0149] In the first example, when the intermediate IAB node (515) receives RLC PDUs, the intermediate IAB node (515) may decide whether to pass the PDUs to the network coding layer or forward the PDUs to the outflow link or RLC channel based on the CU configuration. For example, the intermediate IAB node (515) may perform network coding on the RLC PDUs or forward the PDUs based on the CU configuration and path information for the PDUs. In some cases, the CU configuration may define one or more conditions or mappings for a set of parameters, such as, for example, the BAP address of the incoming PDU, the BAP path identifier of the incoming PDU, the incoming link or RLC channel indicator, and one or more conditions for the outflow link or RLC channel identifier. For example, the CU configuration may provide one or more conditions to indicate whether a PDU arriving on a specific link or channel will be sent to upper layers (e.g., potentially for network coding) or forwarded to a specific outflow link / channel, by returning a specific BAP address and path ID. This information in the CU configuration may also indicate to the intermediate IAB node (515) where to send the RLC PDU or encoded packet segments (e.g., on which path or to an upper layer).

[0150] In the second example, the intermediate IAB node (515) may receive encoded RLC PDUs on one or more incoming links or RLC channels. The encoded PDUs may be associated with different BAP path identifiers and may return BAP path identifier information in their headers. The intermediate IAB node (515) may reconstruct the original raw PDUs using a linear network code or fountain code decoding operation. Then, the intermediate IAB node (515) may transmit feedback on the outgoing link or RLC channel based on the success of the decoding operation. This second example may, in some cases, improve the latency for providing feedback. For example, the intermediate IAB node (515) may check whether any packet segments have been lost (e.g., due to blocks or congestion nodes) instead of the access IAB node (510), which may be several hops away.

[0151] In some cases, the intermediate IAB node (515) may decode the encoded PDUs (e.g., via network decoding) to restore the original raw PDUs, and may transmit the raw PDUs to other (e.g., downstream) devices in the network. For example, the intermediate IAB node (515) may transmit one or more raw PDUs over wireless links along one or more paths (e.g., among multiple paths). The intermediate IAB node (515) may transmit one or more raw PDUs along a first path via a first wireless link, and one or more raw PDUs along a second path via a second wireless link. The first path may be different from the second path, and the first wireless link may be different from or the same as the second wireless link. In some examples, each PDU may include a path identifier.

[0152] If network coding is disabled at the intermediate IAB node (515) for a set of RLC PDUs, the BAP layer may route (e.g., map) the incoming PDUs of the set to an outgoing or outgoing link (e.g., an RLC channel) based on the routing configuration (e.g., bearer mapping) for the set. In this example, the intermediate IAB node (515) may check the BAP addresses of the incoming PDUs, find a mismatch for its own BAP address, and forward the PDUs to an outgoing RLC channel (e.g., instead of forwarding traffic to upper layers). In this example where network coding is disabled at the intermediate IAB node (515), if the intermediate IAB node (515) is not an access IAB node, the intermediate IAB node (515) may forward the received packet segments along a path as indicated by the header information of the packet segments.

[0153] In some cases, the activation and deactivation of network coding functionality may be determined by the IAB donor CU (525). For example, the IAB donor CU (525) may activate or deactivate the NCL (505) at the IAB intermediate node (515). The IAB donor node CU (525) may indicate activation or deactivation based on the BAP address or backhaul RLC channel. Activation or deactivation may be triggered periodically or based on events. In one example, activation or deactivation may be triggered based on modifications to the network topology. For example, when a node is added (e.g., node consolidation) or removed (e.g., node unconsolidation), when the UE (115) is triggered for a handover, or when a path (e.g., between the UE and the donor IAB node) is created, released, or modified, network coding may be triggered to be activated or deactivated for one or more IAB nodes of the IAB network. Network coding may be triggered by reports from UEs (115) or by IAB node MTs indicating a wireless link failure (RLF). In some cases, network coding may be triggered based on buffer status reports indicating congestion at IAB nodes. In some examples, network coding may be activated based on the establishment, release, or modification of RLC channels. Intermediate nodes may receive encoder / decoder configurations via RRC signaling or F1-AP interface messages.

[0154] In some cases, the intermediate node may buffer data before enabling network coding. The amount of data to be buffered may be configured by the donor IAB node's CU. The amount of available data may be a trigger to enable or disable network coding. For example, if the intermediate IAB node determines that the amount of data for one or more received packets in a packet flow satisfies a network coding threshold, the intermediate IAB node may perform network encoding operations on the received packets in the packet flow.

[0155] FIG. 6 illustrates examples of wireless communication systems (600 and 601) that support reducing feedback latency for network coding in wireless backhaul communication networks according to embodiments of the present disclosure. In some examples, the wireless communication systems (600 and 601) may implement embodiments of wireless communication systems (100 or 200).

[0156] The wireless communication system (600) may be an example of an IAB network having multiple IAB donor DUs (605). For example, data for a UE (115-a) may be transmitted by an IAB donor DU (605-a) and an IAB donor DU (605-b). Data from the IAB donor DUs (605) may be transmitted along intermediate IAB nodes (610) to an access IAB node (615-a), and the access IAB node (615-a) may transmit data to the UE (115-a). In some examples, devices in the wireless communication system (600) may communicate through wireless communication links such as wireless links (620-a and 620-b).

[0157] Network coding at intermediate IAB nodes (610) may be enabled. If network coding at intermediate nodes (610) is not enabled, the encoded packets (e.g., packet segments) may not have a common source and a common destination because the wireless communication system (600) may have two separate IAB donor DUs (605). By implementing the techniques described herein, the common source for the packet segments may be an intermediate IAB node (610-a), and the common destination for the packet segments may be an access IAB node (615-a).

[0158] In one example, the IAB donor DU (605-a) and the IAB donor DU (605-b) may transmit RLC PDUs reaching the intermediate IAB node (610-a) to the intermediate IAB nodes (610). The intermediate IAB node (610-a) may perform network encoding (e.g., fountain coding) to generate packet segments. Then, the intermediate IAB node (610-a) may transmit the packet segments to the access IAB node (615-a) over different paths. The access IAB node (615-a) may receive the packet segments, decode the packet segments, and transmit the data to an upper layer for transmission to the UE (115-a). By implementing these techniques, network coding and decoding may be supported for IAB systems having multiple IAB donor DUs.

[0159] Supporting network coding and decoding at intermediate nodes can also shorten the feedback loop in the wireless communication system (600). For example, instead of the access IAB node (615-a) providing feedback entirely back to the IAB donor DU (605), the access IAB node (615-a) may provide feedback to the intermediate IAB node (610-a). Thus, end-to-end feedback latency may have fewer hops than in systems without network coding and decoding at intermediate nodes. Once the access IAB node (615-a) can recover the original PDUs from the packet segments transmitted by the intermediate IAB node (610-a), the access IAB node (615-a) may send an acknowledgment to the intermediate IAB node (610-a).

[0160] Additionally, in some examples, after decoding the received packets or packet segments, the intermediate IAB node (610-a) may transmit packets containing the original PDUs to other devices in the network, such as the access IAB node (615-a). In some cases, the intermediate IAB node (610-b) may transmit multiple packets along paths through wireless links. For example, the intermediate IAB node (610-b) may transmit a first packet (e.g., a first decoded packet of received encoded packets) to a downstream node through the wireless link (620-a). The first packet may be transmitted along a first path and may include a packet identifier for the first path. The intermediate IAB node (610-b) may transmit a second packet (e.g., a second decoded packet of received encoded packets) to a downstream node via the wireless link (620-b). The second packet may be transmitted along a second path and may include a packet identifier for the second path. In some examples, the first and second packets may be transmitted via the same wireless link (e.g., wireless link (620-a or 620-b)) but along different paths (e.g., the first path is different from the second path). In some cases, the paths may branch further downstream before reaching the destination (e.g., at subsequent IAB nodes).

[0161] Some systems without intermediate node network coding may waste resources generating redundantly encoded segments in the period after the original packets have been successfully decoded at the receiver and before the acknowledgment is received by the transmitter. By having fewer hops, there may be reduced latency between the access IAB node (615-a) that restores the original packets and the intermediate IAB node (610-a) that receives the acknowledgment. Additionally, the longer the chain of packet segments between the transmitter and the receiver, the less likely the encoded segment is to be received correctly, and the longer it takes for the original segments to be restored and the acknowledgment to be issued. For example, there may be fewer hops between the transmitter (e.g., intermediate node (610-a)) and the receiver (e.g., access IAB node (615-a)), which may lead to a lower likelihood of blocking or congestion nodes existing on the path between the devices.

[0162] The wireless communication system (601) may be an example of an IAB network having multiple access IAB nodes (615). For example, data for a UE (115-a) may be transmitted by an IAB donor DU (605-c) along intermediate IAB nodes (610) to an access IAB node (615-b) and an access IAB node (615-c). Then, the access IAB nodes (615) may transmit data to the UE (115-a). In some examples, devices in the wireless communication system (601) may communicate through wireless communication links such as wireless links (620-c and 620-d).

[0163] Network coding at intermediate IAB nodes (610) may be enabled in the wireless communication system (601). If there is no network coding at the intermediate nodes (610), the wireless communication system (600) may have two access IAB nodes (615), so the encoded packets (e.g., packet segments) may not have a common source and a common destination. By implementing the techniques described herein, the common source for the packet segments may be the IAB donor DU (605-c), and the common destination for the packet segments may be the intermediate IAB node (610-b).

[0164] In one example, the IAB donor DU (605-c) may perform network encoding on the RLC PDUs to generate packet segments (e.g., encoded packets). The IAB donor DU (605-c) may also transmit packet segments routed to intermediate IAB nodes (610-b) to intermediate IAB nodes (610). The intermediate IAB node (610-b) may perform network decoding (e.g., fountain decoding) to reassemble the RLC PDUs. Then, the intermediate IAB node (610-b) may transmit the RLC PDUs along the intermediate IAB nodes (610) to access IAB nodes (615). Next, the access IAB node (615-b) may transmit part of the data to the UE (115-b), and the access IAB node (615-c) may transmit part of the data to the UE (115-b). In some cases, the data may be transmitted by a single access IAB node (615). By implementing these techniques, network coding and decoding may be supported for IAB systems having multiple access UEs (115).

[0165] Supporting network coding and decoding at intermediate nodes can also shorten the feedback loop in the wireless communication system (601). For example, instead of the access IAB node (615) providing feedback entirely back to the IAB donor DU (605-c), the intermediate IAB node (610-b) may provide feedback to the IAB donor DU (605-c). Thus, end-to-end feedback latency may have fewer hops than systems without network coding and decoding at intermediate nodes. Once the intermediate IAB node (610-b) can recover the original PDUs from the packet segments transmitted by the IAB donor DU (605-c), the intermediate IAB node (610-b) may send an acknowledgment to the IAB donor DU (605-c).

[0166] Additionally, in some examples, after decoding the received packets or packet segments, the intermediate IAB node (610-b) may transmit packets containing the original PDUs to other devices in the network, such as access IAB nodes (615-b and / or 615-c). In some cases, the intermediate IAB node (610-b) may transmit multiple packets along paths through wireless links. For example, the intermediate IAB node (610-b) may transmit a first packet (e.g., a first decoded packet of received encoded packets) to a downstream node through a wireless link (620-c). The first packet may be transmitted along a first path and may include a packet identifier for the first path. The intermediate IAB node (610-b) may transmit a second packet (e.g., a second decoded packet of received encoded packets) to a downstream node via a wireless link (620-d). The second packet may be transmitted along a second path and may include a packet identifier for the second path. In some examples, the first and second packets may be transmitted via the same wireless link (e.g., wireless link (620-c or 620-d)) but along different paths (e.g., the first path is different from the second path). In some cases, the paths may branch further downstream before reaching the destination (e.g., at subsequent IAB nodes).

[0167] In some cases, the network coding configuration for the intermediate IAB node (610) may be configured by the CU of the IAB donor node. For example, the CU of the IAB donor node may indicate the encoding configuration and decoding configuration for the network coding method to the intermediate IAB node (610). The CU of the IAB donor node may also indicate the data flows for which the intermediate IAB node (610) will perform network coding. For example, the intermediate IAB node (610) may receive a set of raw data packets. In some cases, the intermediate IAB node (610) may decide to perform network coding on the raw data packets based on the header information of the raw data packets or other configurations indicated by the CU of the IAB donor node.

[0168] In some examples, routing information for packet segments may be configured by the CU at the IAB donor node. For example, packets from the CU at the IAB donor node may indicate a data path for a PDU (e.g., raw packet) or a segmented packet. Routing information may be identified at the BAP layer of the intermediate IAB node (610). For example, the intermediate IAB node (610) may identify whether to perform network encoding or decoding based on path identifiers. In some cases, the intermediate IAB node (610) may identify a path to transmit the received data (e.g., raw packets or segmented packets). For example, the intermediate IAB node (610) may check the BAP identifier of the segmented packet and decide whether to perform network coding or forward the segmented packet to another intermediate node corresponding to the BAP identifier. In some cases, the BAP identifier may indicate the path for packets to be transmitted to the receiving device (e.g., through one or more other intermediate IAB nodes (610)).

[0169] If an intermediate node (610) receives raw data packets and performs network coding to generate encoded packets (e.g., encoded packet segments), the intermediate node (610) may identify paths for the encoded packets. In some cases, paths for the encoded packets may be based on priority among paths. In one example, a first path may be identified as having fewer obstacles or overloaded nodes than other paths, and the intermediate node (610) may transmit more encoded packets on the first path than on other paths. The intermediate node (610) may generate encoded packets and transmit the encoded packets on one or more paths until the intermediate node (610) receives an acknowledgment indicating that a receiving device (e.g., an access IAB node (615)) has recovered the raw packets from the encoded packets.

[0170] FIG. 7 illustrates an example of a process flow (700) that supports reducing feedback latency for network coding in wireless backhaul communication networks according to embodiments of the present disclosure. In some embodiments, the process flow (700) may implement embodiments of wireless communication systems (100 or 200). The process flow (700) may include devices of a wireless backhaul communication network. For example, the process flow (700) may include a base station (105-a) and a base station (105-b), each of which may be an example of a base station (105) or an IAB node as described herein with reference to FIG. 1 and FIG. 2. In some cases, the base station (105-b) may be an example of an IAB repeater node (215) as described with reference to FIG. 2, such as an intermediate IAB node. The base station (105-a) may be an example of an IAB node, or an example of a parent node for the base station (105-b) (e.g., or another node closer to the CU of the IAB donor node). The process flow (700) may include a receiver (705) which may be an example of a base station (105), such as a UE (115) or an IAB node, as described with reference to FIG. 1.

[0171] In 710, the base station (105-b) may receive a configuration from a central unit node of the wireless backhaul communication network indicating that network coding is enabled for a packet flow. The packet flow may include one or more raw packets, such as RLC PDUs, that return data for the UE (115). In some cases, the configuration may be received via RRC signaling or application protocol signaling.

[0172] In 715, the base station (105-b) may receive a first packet of a packet flow via a first wireless link from the base station (105-a), which may be a second access node of a wireless backhaul communication network. In some cases, the first wireless link may be an example of an incoming link or an RLC channel. In some examples, the base station (105-b) may determine that the amount of data from one or more received packets of the packet flow satisfies a network coding threshold, and the base station (105-b) may perform a network encoding operation on one or more received packets of the packet flow based on the fact that the network coding threshold is satisfied.

[0173] The base station (105-b) may be an intermediate node between the transmitter of the packet flow (e.g., the DU of the donor IAB node) and the receiver of the packet flow (e.g., the UE (115) or receiver (705) served by another IAB node). The techniques described herein support the base station (105-b) performing network coding as an intermediate node, which may improve the feedback latency or robustness of the wireless backhaul communication network.

[0174] In 725, the base station (105-b) may perform a network encoding procedure to generate encoded packets from the received packets of the packet flow. For example, the base station (105-b) may network encode a first portion of the data of the packet flow containing a first subset of the packets of the packet flow to generate a first encoded packet, and the first subset of packets contains the first packet. In some cases, the base station (105-b) may network encode a second portion of the data of the packet flow containing a second subset of the packets of the packet flow to generate a second encoded packet. In some cases, fountain coding may be an example of a network coding procedure.

[0175] In 730, the base station (105-b) may identify a path for a packet flow. Multiple different IAB nodes may exist in a wireless backhaul communication network, and the base station (105-b) may transmit encoded packets over one of the paths. In 735, the base station (105-b) may transmit a first encoded packet generated based on network encoding a first packet over a second wireless link. In some cases, the configuration may indicate a path selection function, wherein the first encoded packet includes a path identifier of the first path among a set of different paths selected based on the path selection function, and the first encoded packet may be transmitted over the second wireless link along the first path. In some cases, the base station (105-b) may transmit a second encoded packet along the second path among a set of different paths selected based on the path selection function. The base station (105-b) transmits encoded packets over different paths to improve spatial transmission diversity and, in some cases, may increase the possibility of successful recovery of encoded packets in the case of blocks or congested nodes on one of the paths.

[0176] In some cases, the base station (105-b) may receive feedback regarding encoded packets. For example, in 735, the base station (105-b) may receive feedback indicating that each packet from the first part of the data of the packet flow has been successfully received. Based on the feedback, the base station (105-b) may transmit a second encoded packet generated by network encoding a second packet from the second part of the data of the packet flow. For example, the base station (105-b) may receive an indication that some packets of the packet flow have been successfully decoded at the receiver, and then the base station (105-b) may encode other packets of the packet flow into other encoded packets. Additionally or alternatively, the base station (105-b) may receive feedback indicating that at least one packet of the data portion of the packet flow has not been successfully received, and the base station (105-b) may transmit a second encoded packet generated based on network encoding the first packet in response to the feedback.

[0177] FIG. 8 illustrates an example of a process flow (800) that supports reducing feedback latency for network coding in wireless backhaul communication networks according to embodiments of the present disclosure. In some embodiments, the process flow (800) may implement embodiments of wireless communication systems (100 or 200). The process flow (800) may include devices of a wireless backhaul communication network. For example, the process flow (800) may include base stations (105-c, 105-d, 105-e, and 105-f), each of which may be an example of a base station (105) or an IAB node as described herein with reference to FIG. 1 and FIG. 2. In some cases, the base station (105-d) may be an example of an IAB repeater node (215) as described with reference to FIG. 2, such as an intermediate IAB node. Base station (105-c) may be an example of an IAB node, or an example of a parent node for base station (105-d) (e.g., or another node closer to the CU of the IAB donor node).

[0178] In some cases, the central entity node of the wireless backhaul communication network may identify an event to trigger the activation of network coding functionality for a packet flow by the first access node of the wireless backhaul communication network. In some cases, the central entity node may transmit a configuration indicating that network coding is activated for a packet flow to the first access node, such as the base station (105-d).

[0179] In 805, the base station (105-d) may receive a configuration from a central unit node (e.g., a central entity node) of the wireless backhaul communication network indicating that network coding is enabled for the packet flow. In some cases, the configuration may be received via RRC signaling or application protocol signaling.

[0180] In 810, and in some cases, in 815, the base station (105-d) may receive a set of encoded packets of packet flow through one or more wireless links from one or more access nodes of a wireless backhaul communication network.

[0181] In some cases, at 820, the base station (105-d) may perform a network decoding procedure on a set of encoded packets. Network decoding a set of encoded packets may include performing a linear network decoding operation or a fountain decoding operation on the set of encoded packets.

[0182] In 825, the base station (105-d) may transmit one or more decoded packets (e.g., decoded in 820) to a downstream node such as the base station (105-e). The base station (105-d) may transmit the decoded packet(s) to the base station (105-e) via one or more wireless links along one or more paths. Each packet may include a path identifier for the corresponding path. For example, the base station (105-d) may transmit a first decoded packet via a first wireless link along a first path, and the first decoded packet may include a path identifier for the first path.

[0183] In 830, the base station (105-d) may transmit one or more other decoded packets (e.g., decoded in 820) to another downstream node such as the base station (105-f). The base station (105-d) may transmit the decoded packet(s) to the base station (105-f) via one or more wireless links along one or more paths. Each packet may include a path identifier for the corresponding path. For example, the base station (105-d) may transmit a second decoded packet via a second wireless link along a second path, and the second decoded packet may include a path identifier for the second path.

[0184] In 835, the base station (105-d) may transmit a feedback message over the second wireless link indicating whether the network decoding of the set of encoded packets to restore the set of packets was successful or unsuccessful. In this example, the base station (105-d) may perform network decoding as an intermediate node to improve feedback latency. For example, by enabling network coding at the intermediate node, the feedback loop may be shortened (e.g., from the IAB donor DU to the intermediate node or from the intermediate node to the IAB access node).

[0185] FIG. 9 illustrates a block diagram (900) of a device (905) that supports reducing feedback latency for network coding in wireless backhaul communication networks according to embodiments of the present disclosure. The device (905) may be an example of embodiments of a base station (105) as described herein. The device (905) may include a receiver (910), a communication manager (915), and a transmitter (920). The device (905) may also include a processor. Each of these components may communicate with one another (e.g., via one or more buses).

[0186] The receiver (910) may receive information such as packets associated with various information channels, user data, or control information (e.g., information related to reducing feedback latency for control channels, data channels, and network coding in wireless backhaul communication networks). The information may be transmitted to other components of the device (905). The receiver (910) may be an example of an embodiment of the transceiver (1220) described with reference to FIG. 12. The receiver (910) may utilize a single antenna or a set of antennas.

[0187] The communication manager (915) receives a configuration from a central unit node of the wireless backhaul communication network indicating that network coding is enabled for the packet flow, receives a first packet of the packet flow through a first wireless link from a second access node of the wireless backhaul communication network, and may transmit a first encoded packet generated based on network encoding the first packet through a second wireless link. The communication manager (915) may also receive a configuration indicating that network coding is enabled for a packet flow from a central unit node of a wireless backhaul communication network, receive a set of encoded packets of the packet flow through one or more wireless links from one or more access nodes of a wireless backhaul communication network, transmit a first packet among a set of packets restored by network decoding through a first wireless link along a first path among a plurality of different paths, the first packet including a first path identifier, and transmit a second packet among a plurality of packets restored by network decoding through a second wireless link along a second path among a plurality of different paths, the second packet including a second path identifier. The communication manager (915) may also identify an event to trigger the activation of network coding functionality for a packet flow by a first access node of a wireless backhaul communication network, and transmit a configuration to the first access node indicating that network coding is activated for the packet flow. The communication manager (915) may be an example of an embodiment of the communication manager (1210) described herein.

[0188] The communication manager (915) or its sub-components may be implemented in hardware, code executed by a processor (e.g., software or firmware), or any combination thereof. When implemented in code executed by a processor, the functions of the communication manager (915) or its sub-components may be implemented by a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described in this disclosure.

[0189] The communication manager (915) or its sub-components may be physically located in various positions, including distributed so that parts of the functions are implemented at different physical locations by one or more physical components. In some examples, the communication manager (915) or its sub-components may be separate and distinct components according to various aspects of the present disclosure. In some examples, the communication manager (915) or its sub-components may be combined with one or more other hardware components, including but not limited to input / output (I / O) components, transceivers, network servers, other computing devices, one or more other components described in the present disclosure, or combinations thereof according to various aspects of the present disclosure.

[0190] As described herein, actions performed by the base station communication manager (915) may be implemented to realize one or more potential benefits. One implementation may allow the base station (105) to implement network coding schemes for different types of wireless backhaul communication networks. Network coding schemes may provide enhanced robustness against blocks and congested nodes. Supporting network coding at intermediate nodes may enable network coding schemes in, for example, UEs connected to multiple IAB access nodes or IAB networks having multiple IAB donor DUs. Additionally, performing network coding at intermediate nodes may reduce latency for feedback in wireless backhaul communication networks. For example, the intermediate node may decode encoded packets (e.g., packet segments) and provide feedback that may be faster feedback, such as a shorter feedback loop than the feedback loop from the IAB donor DU to the IAB access node.

[0191] The transmitter (920) may transmit signals generated by other components of the device (905). In some examples, the transmitter (920) may be juxtaposed with the receiver (910) in the transceiver module. For example, the transmitter (920) may be an example of an embodiment of the transceiver (1220) described with reference to FIG. 12. The transmitter (920) may utilize a single antenna or a set of antennas.

[0192] FIG. 10 illustrates a block diagram (1000) of a device (1005) that supports reducing feedback latency for network coding in wireless backhaul communication networks according to embodiments of the present disclosure. The device (1005) may be an example of embodiments of the device (905) or base station (105) as described herein. The device (1005) may include a receiver (1010), a communication manager (1015), and a transmitter (1050). The device (1005) may also include a processor. Each of these components may communicate with one another (e.g., via one or more buses).

[0193] The receiver (1010) may receive information such as packets associated with various information channels, user data, or control information (e.g., information related to reducing feedback latency for control channels, data channels, and network coding in wireless backhaul communication networks). The information may be transmitted to other components of the device (1005). The receiver (1010) may be an example of an embodiment of the transceiver (1220) described with reference to FIG. 12. The receiver (1010) may utilize a single antenna or a set of antennas.

[0194] The communication manager (1015) may be an example of an embodiment of the communication manager (915) as described herein. The communication manager (1015) may include a CU configuration receiving component (1020), a packet flow receiving component (1025), a packet transmitting component (1030), a feedback component (1035), an activation event component (1040), and a network coding activation component (1045). The communication manager (1015) may be an example of an embodiment of the communication manager (1210) described herein.

[0195] The CU configuration receiving component (1020) may receive a configuration from a central unit node of the wireless backhaul communication network indicating that network coding is enabled for the packet flow. The packet flow receiving component (1025) may receive a first packet of the packet flow via a first wireless link from a second access node of the wireless backhaul communication network. The packet transmitting component (1030) may transmit a first encoded packet generated based on network encoding the first packet via a second wireless link.

[0196] The CU configuration receiving component (1020) may receive a configuration from a central unit node of the wireless backhaul communication network indicating that network coding is enabled for the packet flow. The packet flow receiving component (1025) may receive a set of encoded packets of the packet flow from one or more access nodes of the wireless backhaul communication network via one or more wireless links. The feedback component (1035) may transmit a feedback message via a second wireless link indicating whether network decoding of the set of encoded packets for restoring the set of packets was successful or unsuccessful.

[0197] The activation event component (1040) may identify an event to trigger the activation of network coding functionality for a packet flow by the first access node of the wireless backhaul communication network. The network coding activation component (1045) may transmit a configuration to the first access node indicating that network coding is enabled for the packet flow.

[0198] The transmitter (1050) may transmit signals generated by other components of the device (1005). In some examples, the transmitter (1050) may be juxtaposed with the receiver (1010) in a transceiver module. For example, the transmitter (1050) may be an example of an embodiment of the transceiver (1220) described with reference to FIG. 12. The transmitter (1050) may utilize a single antenna or a set of antennas.

[0199] FIG. 11 illustrates a block diagram (1100) of a communication manager (1105) that supports reducing feedback latency for network coding in wireless backhaul communication networks according to embodiments of the present disclosure. The communication manager (1105) may be an example of embodiments of the communication manager (915), the communication manager (1015), or the communication manager (1210) described herein. The communication manager (1105) may include a CU configuration receiving component (1110), a packet flow receiving component (1115), a packet transmitting component (1120), a path selection component (1125), a feedback component (1130), a packet destination component (1135), a network coding component (1140), an activation event component (1145), and a network coding activation component (1150). Each of these modules may communicate directly or indirectly with one another (e.g., through one or more buses).

[0200] The CU configuration receiving component (1110) may also receive a configuration from the central unit node of the wireless backhaul communication network indicating that network coding is enabled for the packet flow.

[0201] In some examples, the CU configuration receiving component (1110) may receive wireless resource control signaling or application protocol signaling indicating the configuration. In some cases, the configuration indicating that network coding is enabled for packet flow is received based on a modification of the network topology. In some cases, the configuration indicating that network coding is enabled for packet flow is received based on a wireless link failure report. In some cases, the configuration indicating that network coding is enabled for packet flow is received based on a buffer status reporting indicating congestion. In some cases, the configuration indicating that network coding is enabled for packet flow is received based on the establishment, release, or modification of a wireless link control channel.

[0202] The packet flow receiving component (1115) may receive a first packet of the packet flow from a second access node of the wireless backhaul communication network via a first wireless link. In some examples, the packet flow receiving component (1115) may receive a set of encoded packets of the packet flow from one or more access nodes of the wireless backhaul communication network via one or more wireless links.

[0203] In some examples, the packet flow receiving component (1115) may determine the destination address of the first packet. In some examples, the packet flow receiving component (1115) may identify a mismatch between the address of the first access node and the destination address. In some examples, the packet flow receiving component (1115) may provide the first packet for network encoding based on a configuration indicating to perform network coding when an address mismatch is identified. In some examples, the packet flow receiving component (1115) may receive the first encoded packet among a set of encoded packets containing a first path identifier. In some examples, the packet flow receiving component (1115) may receive the second encoded packet among a set of encoded packets containing a second path identifier.

[0204] In some cases, the configuration indicates that network coding is performed when an address mismatch is identified based on conditions regarding at least one of the address of the first packet, the path identifier of the first packet, the first wireless link, the second wireless link, or any combination thereof. In some cases, the first wireless link is an incoming link or a wireless link control channel. In some cases, the second wireless link is an outgoing link or a wireless link control channel. In some cases, the first path identifier is different from the second path identifier.

[0205] The packet transmission component (1120) may transmit a first encoded packet generated based on network encoding a first packet over a second wireless link. In some examples, the packet transmission component (1120) may transmit a first packet among a set of packets restored by network decoding of a plurality of encoded packets over a first wireless link along a first path among a set of different paths, and the first packet includes a first path identifier.

[0206] In some examples, the packet transmission component (1120) may transmit a second packet among a set of packets restored by network decoding of a plurality of encoded packets over a second wireless link along a second path among a set of different paths, and the second packet includes a second path identifier. In some cases, a first encoded packet is generated based on network encoding a first packet of a packet flow and at least one other packet. In some cases, the first path is different from the second path.

[0207] The feedback component (1130) may transmit a feedback message over the fourth wireless link indicating whether network decoding of a set of encoded packets for restoring a set of packets is successful or unsuccessful. In some examples, the feedback component (1130) may receive feedback indicating that at least one packet of a portion of data of a packet flow has not been successfully received, and the portion of data includes a first packet. In some examples, the feedback component (1130) may transmit a second encoded packet generated based on network encoding the first packet in response to the feedback.

[0208] In some examples, the feedback component (1130) may receive feedback indicating that each packet from a first part of the data of the packet flow has been successfully received, and the first part of the data includes a first packet. In some examples, the feedback component (1130) may transmit a second encoded packet generated based on network encoding a second packet from a second part of the data of the packet flow based on the feedback. The activation event component (1145) may identify an event to trigger the activation of network coding functionality for the packet flow by a first access node of the wireless backhaul communication network. In some examples, the activation event component (1145) may identify an event based on a modification of the network topology of the wireless backhaul communication network. In some examples, the activation event component (1145) may identify an event based on receiving a wireless link failure report. In some cases, the activation event component (1145) may determine the destination address of the first encoded packet among a plurality of encoded packets, identify a mismatch between the address of the first access node and the destination address, and provide the first encoded packet for network decoding based on conditions in a configuration indicating that network decoding should be performed when an address mismatch is identified. In some cases, the conditions are for the destination address, the path identifier of the first encoded packet, or both. In some cases, the activation event component (1145) may receive an unencoded packet, identify a mismatch between the address of the first access node and the destination address of the unencoded packet, and transmit the unencoded packet over an outflow wireless link or a wireless link control channel based on conditions in a configuration indicating that packet forwarding should be performed when an address mismatch is identified.

[0209] In some examples, the activation event component (1145) may identify an event based on receiving buffer status reporting indicating congestion at one or more access nodes of the wireless backhaul communication network. In some examples, the activation event component (1145) may identify an event based on the establishment, release, or modification of a wireless link control channel at one or more access nodes of the wireless backhaul communication network. In some examples, the activation event component (1145) may identify an event based on the elapsed time period.

[0210] The network coding enable component (1150) may transmit a configuration to the first access node indicating that network coding is enabled for the packet flow. In some examples, the network coding enable component (1150) may transmit a configuration indicating a path selection function for distributing encoded packets between sets of different paths. In some examples, the network coding enable component (1150) may transmit a configuration indicating that network coding should be performed when an address mismatch is identified. In some examples, the network coding enable component (1150) may transmit wireless resource control signaling or application protocol signaling indicating the configuration.

[0211] In some cases, the path selection function indicates to distribute encoded packets uniformly or non-uniformly among sets of different paths. In some cases, the configuration indicates to perform network coding when an address mismatch is identified based on conditions regarding at least one of the packet address of the packet flow, the packet path identifier, the first wireless link, the second wireless link, or any combination thereof. In some cases, the first wireless link is an incoming link or a wireless link control channel. In some cases, the second wireless link is an outgoing link or a wireless link control channel.

[0212] The path selection component (1125) may receive a configuration indicating a path selection function, wherein a first encoded packet contains a path identifier of a first path among a set of different paths selected based on the path selection function and is transmitted along a second wireless link along the first path. In some examples, the path selection component (1125) may transmit a second encoded packet generated based on network encoding the first packet. In some examples, the path selection component (1125) may transmit a second encoded packet along a second path among a set of different paths selected based on the path selection function. In some cases, the path selection function indicates that encoded packets be distributed evenly or unevenly among a set of different paths.

[0213] The packet destination component (1135) may receive the second packet over the first wireless link. In some examples, the packet destination component (1135) may determine the destination address of the second packet. In some examples, the packet destination component (1135) may identify a mismatch between the address of the first access node and the destination address. In some examples, the packet destination component (1135) may transmit the second packet over the second wireless link or the third wireless link based on a configuration indicating to perform packet forwarding when an address mismatch is identified.

[0214] In some examples, the packet destination component (1135) may transmit a configuration indicating that packet forwarding should be performed when an address mismatch is identified. In some cases, the configuration indicates that packet forwarding should be performed when an address mismatch is identified based on conditions regarding at least one of the address of the first packet, the path identifier of the first packet, the first wireless link, the second wireless link, the third wireless link, or any combination thereof. In some cases, the first wireless link is an incoming link or a wireless link control channel. In some cases, the second wireless link is an outgoing link or a wireless link control channel.

[0215] In some cases, the configuration indicates that packet forwarding is performed when an address mismatch is identified based on conditions regarding at least one of the address of a packet in a packet flow, the path identifier of a packet, a first wireless link, a second wireless link, or any combination thereof. In some cases, the first wireless link is an incoming link or a wireless link control channel. In some cases, the second wireless link is an outgoing link or a wireless link control channel.

[0216] The network coding component (1140) may determine that the amount of data from one or more received packets of a packet flow satisfies a network coding threshold. In some examples, the network coding component (1140) may perform a network encoding operation on one or more received packets of a packet flow based on whether the network coding threshold is satisfied. In some examples, network encoding a first packet includes performing a linear network encoding operation or a fountain encoding operation on the first packet. In some examples, the network coding component (1140) may network encode a first portion of data of a packet flow comprising a first subset of packets of the packet flow to generate a first encoded packet, the first subset of packets comprising the first packet.

[0217] In some examples, the network coding component (1140) may network encode a second portion of the data of a packet flow containing a second subset of packets of the packet flow to generate a second encoded packet. In some examples, the network coding component (1140) may network decode a set of encoded packets, which may include performing a linear network decoding operation or a fountain decoding operation on the set of encoded packets. In some cases, the second subset of packets includes at least one packet from a first subset of packets.

[0218] FIG. 12 illustrates a diagram of a system (1200) including a device (1205) that supports reducing feedback latency for network coding in wireless backhaul communication networks according to embodiments of the present disclosure. The device (1205) may be an example of a device (905), a device (1005), or a base station (105) as described herein, or may include components thereof. The device (1205) may include components for bidirectional voice and data communication, including a communication manager (1210), a network communication manager (1215), a transceiver (1220), an antenna (1225), a memory (1230), a processor (1240), and an inter-station communication manager (1245), for transmitting and receiving communications. These components may communicate electronically through one or more buses (e.g., a bus (1250)).

[0219] The communication manager (1210) receives a configuration from a central unit node of the wireless backhaul communication network indicating that network coding is enabled for a packet flow, receives a first packet of the packet flow through a first wireless link from a second access node of the wireless backhaul communication network, and may transmit a first encoded packet generated based on network encoding the first packet through a second wireless link. A communication manager (1210) may also receive a configuration indicating that network coding is enabled for a packet flow from a central unit node of a wireless backhaul communication network, receive a set of encoded packets of a packet flow through one or more wireless links from one or more access nodes of a wireless backhaul communication network, and transmit a first packet among a set of packets restored by network decoding of a plurality of encoded packets through a first wireless link along a first path among a plurality of different paths, wherein the first packet includes a first path identifier, and transmit a second packet among a plurality of packets restored by network decoding of a plurality of encoded packets through a second wireless link along a second path among a plurality of different paths, wherein the second packet includes a second path identifier. The communication manager (1210) may also identify an event to trigger the activation of network coding functionality for a packet flow by a first access node of the wireless backhaul communication network, and transmit a configuration to the first access node indicating that network coding is activated for the packet flow.

[0220] The network communication manager (1215) may manage communication with the core network (e.g., through one or more wired backhaul links). For example, the network communication manager (1215) may manage the transmission of data communications to client devices such as one or more UEs (115).

[0221] The transceiver (1220) may communicate bidirectionally through one or more antennas, wired or wireless links, as described above. For example, the transceiver (1220) may represent a wireless transceiver and may communicate bidirectionally with another wireless transceiver. The transceiver (1220) may also include a modem for modulating packets, providing the modulated packets to the antennas for transmission, and demodulating packets received from the antennas.

[0222] In some cases, the wireless device may include a single antenna (1225). However, in some cases, the device may have more than one antenna (1225) capable of simultaneously transmitting or receiving multiple wireless transmissions.

[0223] Memory (1230) may include RAM, ROM, or a combination thereof. Memory (1230) may store computer-readable code (1235) containing instructions, which, when executed by a processor (e.g., processor (1240)), enable the device to perform the various functions described herein. In some cases, memory (1230) may include a BIOS, which, among others, may control basic hardware or software operations, such as interactions with peripheral components or devices.

[0224] The processor (1240) may include intelligent hardware devices (e.g., general-purpose processor, DSP, CPU, microcontroller, ASIC, FPGA, programmable logic device, discrete gate or transistor logic component, discrete hardware component, or any combination thereof). In some cases, the processor (1240) may be configured to operate a memory array using a memory controller. In some cases, the memory controller may be integrated into the processor (1240). The processor (1240) may be configured to execute computer-readable instructions stored in memory (e.g., memory (1230)) to enable the device (1205) to perform various functions (e.g., functions or tasks that support reducing feedback latency for network coding in wireless backhaul communication networks).

[0225] The inter-station communication manager (1245) may manage communication with other base stations (105) and may include a controller or scheduler to control communication with UEs (115) in cooperation with other base stations (105). For example, the inter-station communication manager (1245) may coordinate the scheduling of transmissions to UEs (115) for various interference mitigation techniques such as beamforming or joint transmission. In some examples, the inter-station communication manager (1245) may provide an X2 interface within LTE / LTE-A wireless communication network technology to provide communication between base stations (105).

[0226] Code (1235) may include instructions for implementing aspects of the present disclosure, including instructions for supporting wireless communication. Code (1235) may be stored in a non-transient computer-readable medium, such as system memory or other types of memory. In some cases, Code (1235) may not be directly executable by the processor (1240), but may enable the computer to perform the functions described herein (e.g., when compiled and executed).

[0227] FIG. 13 illustrates a flowchart illustrating a method (1300) that supports reducing feedback latency for network coding in wireless backhaul communication networks according to embodiments of the present disclosure. Operations of method (1300) may be implemented by a base station (105) or its components as described herein. For example, operations of method (1300) may be performed by a communication manager as described with reference to FIGS. 9 through 12. In some examples, the base station may perform the functions described below by executing a set of commands to control the functional elements of the base station. Additionally or alternatively, the base station may perform embodiments of the functions described below using special-purpose hardware.

[0228] In 1305, the base station may receive a configuration from a central unit node of a wireless backhaul communication network indicating that network coding is enabled for a packet flow. The operations of 1305 may be performed according to the methods described herein. In some examples, aspects of the operations of 1305 may be performed by a CU configuration receiving component as described with reference to FIGS. 9 through 12.

[0229] In 1310, the base station may receive a first packet of a packet flow through a first wireless link from a second access node of a wireless backhaul communication network. The operations of 1310 may be performed according to the methods described herein. In some examples, aspects of the operations of 1310 may be performed by a packet flow receiving component as described with reference to FIGS. 9 through 12.

[0230] In 1315, the base station may transmit a first encoded packet generated based on network encoding a first packet over a second wireless link. The operations of 1315 may be performed according to the methods described herein. In some examples, aspects of the operations of 1315 may be performed by a packet transmission component as described with reference to FIGS. 9 through 12.

[0231] FIG. 14 illustrates a flowchart illustrating a method (1400) that supports reducing feedback latency for network coding in wireless backhaul communication networks according to embodiments of the present disclosure. Operations of method (1400) may be implemented by a base station (105) or its components as described herein. For example, operations of method (1400) may be performed by a communication manager as described with reference to FIGS. 9 through 12. In some examples, the base station may perform the functions described below by executing a set of commands to control the functional elements of the base station. Additionally or alternatively, the base station may perform embodiments of the functions described below using special-purpose hardware.

[0232] In 1405, the base station may receive a configuration from a central unit node of a wireless backhaul communication network indicating that network coding is enabled for a packet flow. The operations of 1405 may be performed according to the methods described herein. In some examples, aspects of the operations of 1405 may be performed by a CU configuration receiving component as described with reference to FIGS. 9 through 12.

[0233] In 1410, the base station may receive a first packet of a packet flow through a first wireless link from a second access node of a wireless backhaul communication network. The operations of 1410 may be performed according to the methods described herein. In some examples, aspects of the operations of 1410 may be performed by a packet flow receiving component as described with reference to FIGS. 9 through 12.

[0234] In 1415, the base station may transmit a first encoded packet generated based on network encoding a first packet over a second wireless link. The operations of 1415 may be performed according to the methods described herein. In some examples, aspects of the operations of 1415 may be performed by a packet transmission component as described with reference to FIGS. 9 through 12.

[0235] In 1420, the base station may receive feedback indicating that each packet from a first part of data of a packet flow has been successfully received, and the first part of data includes a first packet. The operations of 1420 may be performed according to the methods described herein. In some examples, aspects of the operations of 1420 may be performed by a feedback component as described with reference to FIGS. 9 through 12.

[0236] In 1425, the base station may transmit a second encoded packet generated based on network encoding a second packet from a second part of the data of the packet flow based on feedback. The operations of 1425 may be performed according to the methods described herein. In some examples, aspects of the operations of 1425 may be performed by a feedback component as described with reference to FIGS. 9 through 12.

[0237] FIG. 15 illustrates a flowchart illustrating a method (1500) that supports reducing feedback latency for network coding in wireless backhaul communication networks according to embodiments of the present disclosure. Operations of method (1500) may be implemented by a base station (105) or its components as described herein. For example, operations of method (1500) may be performed by a communication manager as described with reference to FIGS. 9 through 12. In some examples, the base station may perform the functions described below by executing a set of commands to control the functional elements of the base station. Additionally or alternatively, the base station may perform embodiments of the functions described below using special-purpose hardware.

[0238] In 1505, the base station may receive a configuration from a central unit node of a wireless backhaul communication network indicating that network coding is enabled for a packet flow. The operations of 1505 may be performed according to the methods described herein. In some examples, aspects of the operations of 1505 may be performed by a CU configuration receiving component as described with reference to FIGS. 9 through 12.

[0239] In 1510, the base station may receive a first packet of a packet flow through a first wireless link from a second access node of a wireless backhaul communication network. The operations of 1510 may be performed according to the methods described herein. In some examples, aspects of the operations of 1510 may be performed by a packet flow receiving component as described with reference to FIGS. 9 through 12.

[0240] In 1515, the base station may network-encode a first portion of data of a packet flow comprising a first subset of packets of the packet flow to generate a first encoded packet, and the first subset of packets comprises the first packet. The operations of 1515 may be performed according to the methods described herein. In some examples, aspects of the operations of 1515 may be performed by a network coding component as described with reference to FIGS. 9 through 12.

[0241] In 1520, the base station may transmit a first encoded packet generated based on network encoding a first packet over a second wireless link. The operations of 1520 may be performed according to the methods described herein. In some examples, aspects of the operations of 1520 may be performed by a packet transmission component as described with reference to FIGS. 9 through 12.

[0242] FIG. 16 illustrates a flowchart illustrating a method (1600) that supports reducing feedback latency for network coding in wireless backhaul communication networks according to embodiments of the present disclosure. Operations of method (1600) may be implemented by a base station (105) or its components as described herein. For example, operations of method (1600) may be performed by a communication manager as described with reference to FIGS. 9 through 12. In some examples, the base station may perform the functions described below by executing a set of commands to control the functional elements of the base station. Additionally or alternatively, the base station may perform embodiments of the functions described below using special-purpose hardware.

[0243] In 1605, the base station may receive a configuration from a central unit node of a wireless backhaul communication network indicating that network coding is enabled for a packet flow. The operations of 1605 may be performed according to the methods described herein. In some examples, aspects of the operations of 1605 may be performed by a CU configuration receiving component as described with reference to FIGS. 9 through 12.

[0244] In 1610, the base station may receive a set of encoded packets of a packet flow through one or more wireless links from one or more access nodes of a wireless backhaul communication network. The operations of 1610 may be performed according to the methods described herein. In some examples, aspects of the operations of 1610 may be performed by a packet flow receiving component as described with reference to FIGS. 9 through 12.

[0245] In 1615, the base station may transmit a first packet among a set of packets restored by network decoding of a plurality of encoded packets through a first wireless link along a first path among a plurality of different paths, and the first packet includes a first path identifier. The operations of 1615 may be performed according to the methods described herein. In some examples, aspects of the operations of 1615 may be performed by a feedback component as described with reference to FIGS. 9 through 12.

[0246] In 1620, the base station may transmit a second packet among a set of packets restored by network decoding of a plurality of encoded packets through a second wireless link along a second path among a plurality of different paths, and the second packet includes a second path identifier. The operations of 1620 may be performed according to the methods described herein. In some examples, aspects of the operations of 1620 may be performed by a feedback component as described with reference to FIGS. 9 through 12.

[0247] FIG. 17 illustrates a flowchart illustrating a method (1700) that supports reducing feedback latency for network coding in wireless backhaul communication networks according to embodiments of the present disclosure. Operations of method (1700) may be implemented by a base station (105) or its components as described herein. For example, operations of method (1700) may be performed by a communication manager as described with reference to FIGS. 9 through 12. In some examples, the base station may perform the functions described below by executing a set of commands to control the functional elements of the base station. Additionally or alternatively, the base station may perform embodiments of the functions described below using special-purpose hardware.

[0248] In 1705, the base station may identify an event to trigger the activation of network coding functionality for a packet flow by a first access node of the wireless backhaul communication network. The operations of 1705 may be performed according to the methods described herein. In some examples, aspects of the operations of 1705 may be performed by an activation event component as described with reference to FIGS. 9 through 12.

[0249] In 1710, the base station may transmit a configuration to the first access node indicating that network coding is enabled for a packet flow. The operations of 1710 may be performed according to the methods described herein. In some examples, aspects of the operations of 1710 may be performed by a network coding enable component as described with reference to FIGS. 9 through 12.

[0250] It should be noted that the methods described herein describe possible implementations, and that the operations and steps may be rearranged or otherwise modified, and that other implementations are possible. Additionally, aspects from two or more of the methods may be combined.

[0251] The techniques described herein may be used for various wireless communication systems, such as Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiple Access (OFDMA), Single Carrier Frequency Division Multiple Access (SC-FDMA), and other systems. CDMA systems may implement wireless technologies such as CDMA2000, Universal Terrestrial Radio Access (UTRA), etc. CDMA2000 covers IS-2000, IS-95, and IS-856 standards. IS-2000 releases may generally be referred to as CDMA2000 1X, 1X, etc. IS-856 (TIA-856) is generally referred to as CDMA2000 1xEV-DO, High Rate Packet Data (HRPD), etc. UTRA includes Wideband CDMA (WCDMA) and other variations of CDMA. TDMA systems may implement wireless technologies such as the Global System for Mobile Communications (GSM).

[0252] OFDMA systems may also implement wireless technologies such as Ultra Mobile Broadband (UMB), Evolved UTRA (E-UTRA), IEEE (Institute of Electrical and Electronics Engineers) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM, etc. UTRA and E-UTRA are part of the Universal Mobile Telecommunications System (UMTS). LTE, LTE-A, and LTE-A Pro are releases of UMTS using E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, LTE-A Pro, NR, and GSM are described in literature from the organization named "Third Generation Partnership Project" (3GPP). CDMA2000 and UMB are described in literature from the organization named "Third Generation Partnership Project 2 (3GPP2)". The techniques described herein may be used for systems and wireless technologies other than those mentioned herein. Aspects of LTE, LTE-A, LTE-A Pro, or NR systems may be described for illustrative purposes, and the terms LTE, LTE-A, LTE-A Pro, or NR may be used throughout the description, but the techniques described herein are applicable beyond LTE, LTE-A, LTE-A Pro, or NR applications.

[0253] Macro cells generally cover a relatively large geographical area (e.g., a radius of several kilometers) and may allow unrestricted access by UEs with service subscriptions to a network provider. Small cells may be associated with a low-power supply base station compared to macro cells, and small cells may operate in the same or different (e.g., licensed, unlicensed, etc.) frequency bands as macro cells. Small cells may include pico cells, femto cells, and micro cells depending on various examples. Pico cells may, for example, cover a small geographical area and may allow unrestricted access by UEs with service subscriptions to a network provider. Femto cells may also cover a small geographical area (e.g., a home) and may provide restricted access by UEs associated with the femto cell (e.g., UEs within a closed subscriber group (CSG), UEs for users within a home, etc.). An eNB for a macro cell may be referred to as a macro eNB. An eNB for a small cell may be referred to as a small cell eNB, pico eNB, femto eNB, or home eNB. The eNB may support one or multiple (e.g., two, three, four, etc.) cells, and may also support communications using one or multiple component carriers.

[0254] The wireless communication systems described herein may support synchronous or asynchronous operation. For synchronous operation, base stations may have similar frame timings, and transmissions from different base stations may be roughly aligned in time. For asynchronous operation, base stations may have different frame timings, and transmissions from different base stations may not be aligned in time. The techniques described herein may be used for either synchronous or asynchronous operation.

[0255] The information and signals described herein may be represented using any various different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout this description may be represented by voltage, current, electromagnetic waves, magnetic fields or magnetic particles, optical fields or optical particles, or any combination thereof.

[0256] The various exemplary blocks and modules described in connection with the disclosure herein may be implemented or performed by a general-purpose processor, a DSP, an ASIC, an FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but alternatively, the processor may be any conventional processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors combined with a DSP core, or any other such configuration).

[0257] The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions may be stored or transmitted over a computer-readable medium as one or more instructions or code. Other examples and implementations are within the scope of this disclosure and the appended claims. For example, due to the nature of the software, the functions described herein may be implemented using software executed by a processor, hardware, firmware, hardwiring, or any combination thereof. Features implementing the functions may also be physically located at various positions, including distributed so that parts of the functions are implemented at different physical locations.

[0258] Computer-readable media include both communication media comprising any medium that facilitates the transfer of a computer program from one place to another, and non-transient computer storage media. A non-transient storage medium may be any available medium that can be accessed by a general-purpose or special-purpose computer. By example, but not by limitation, non-transient computer-readable media may include random access memory (RAM), read-only memory (ROM), electrically erasable programmable ROM (EEPROM), flash memory, compact disc (CD) ROM or other optical disc storage, magnetic disc storage or other magnetic storage devices, or any other non-transient medium that can be used to record or store desired program code means in the form of instructions or data structures and can be accessed by a general-purpose or special-purpose computer or a general-purpose or special-purpose processor. Additionally, any connection is appropriately named as a computer-readable medium. For example, if software is transmitted from a website, server, or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of a medium. As used herein, disk and disc include CD, laser disc, optical disc, digital multifunction disc (DVD), floppy disc, and Blu-ray disc, wherein disks typically reproduce data magnetically, while discs reproduce data optically using lasers. The above combinations are also included within the scope of computer-readable media.

[0259] As used herein, including in the claims, the word “or” as used in a list of items (e.g., a list of items beginning with phrases such as “at least one of” or “one or more of”) indicates a comprehensive list such that, for example, a list of at least one of A, B, or C means A or B or C or AB or AC or BC or ABC (i.e., A, B, and C). Also, as used herein, the phrase “based on” should not be interpreted as a reference to a closed set of conditions. For example, an exemplary step described as “based on condition A” may be based on both condition A and condition B without departing from the scope of this disclosure. That is, as used herein, the phrase “based on” should be interpreted in the same way as the phrase “at least partially based on”.

[0260] In the attached drawings, similar components or features may have the same reference label. Additionally, various components of the same type may be distinguished by placing a dash and a second label following the reference label to distinguish between similar components. If only the first reference label is used in the specification, the description is applicable to any component among similar components having the same first reference label, regardless of the second reference label or other subsequent reference labels.

[0261] The descriptions provided herein in connection with the accompanying drawings describe exemplary configurations and do not represent all examples that may be implemented or are within the scope of the claims. As used herein, the term “exemplary” means “functioning as an example, case, or example,” and does not mean “preferred over other examples” or “advantageous.” The detailed description includes specific details for the purpose of providing an understanding of the described techniques. However, these techniques may be practiced without these specific details. In some cases, widely known structures and devices are illustrated in block diagram form to avoid obscuring the concepts of the described examples.

[0262] The description in this specification is provided to enable those skilled in the art to manufacture or use the present disclosure. Various modifications to the present disclosure will be readily apparent to those skilled in the art, and general principles defined in this specification may be applied to other variations without departing from the scope of the present disclosure. Accordingly, the present disclosure is not limited to the examples and designs described in this specification, but should be given the broadest scope consistent with the principles and novel features disclosed in this specification.

Claims

Claim 1 A method for wireless communications by a first access node of a wireless backhaul communication network, comprising: receiving from a central unit node of the wireless backhaul communication network a configuration indicating that network coding is enabled for a packet flow, wherein the packet flow returns data to a specific user equipment (UE); receiving from a second access node of the wireless backhaul communication network a first packet of the packet flow via a first wireless link; and transmitting through a second wireless link a first encoded packet generated at least partially based on network encoding the first packet. Claim 2 A method for wireless communications by a first access node of a wireless backhaul communication network, wherein the step of receiving the configuration includes the step of receiving the configuration indicating a path selection function, and the first encoded packet includes a path identifier of a first path among a plurality of different paths selected at least partially based on the path selection function, and is transmitted through the second wireless link along the first path. Claim 3 A method for wireless communications by a first access node of a wireless backhaul communication network, further comprising the step of transmitting a second encoded packet generated at least partially based on network encoding the first packet in claim 2. Claim 4 A method for wireless communications by a first access node of a wireless backhaul communication network, wherein the step of transmitting the second encoded packet comprises transmitting the second encoded packet along a second path among a plurality of different paths selected at least partially based on the path selection function. Claim 5 A method for wireless communications by a first access node of a wireless backhaul communication network, wherein, in claim 2, the path selection function indicates to distribute encoded packets uniformly or non-uniformly among the plurality of different paths. Claim 6 A method for wireless communications by a first access node of a wireless backhaul communication network, wherein, in claim 1, the step of receiving feedback indicating that at least one packet of a portion of data of the packet flow has not been successfully received, said portion of data comprising said first packet; and the step of transmitting a second encoded packet generated at least partially based on network encoding said first packet in response to said feedback. Claim 7 A method for wireless communications by a first access node of a wireless backhaul communication network, wherein, in claim 1, the step of receiving feedback indicating that each packet from a first part of data of the packet flow has been successfully received, wherein the first part of the data comprises a first packet; and the step of transmitting a second encoded packet generated at least partially based on network encoding a second packet from a second part of data of the packet flow based at least partially based on the feedback. Claim 8 A method for wireless communications by a first access node of a wireless backhaul communication network, wherein the first encoded packet is generated at least partially based on network encoding the first packet and at least one other packet of the packet flow. Claim 9 A method for wireless communications by a first access node of a wireless backhaul communication network, wherein, in claim 1, the step of receiving the first packet of the packet flow through the first wireless link comprises: identifying the destination address of the first packet; and identifying a mismatch between the address of the first access node and the destination address. Claim 10 A method for wireless communications by a first access node of a wireless backhaul communication network, further comprising the step of providing the first packet for network encoding based at least partially on the configuration indicating to perform network coding when an address mismatch is identified in claim 9. Claim 11 A method for wireless communications by a first access node of a wireless backhaul communication network, wherein the configuration indicates to perform network coding when an address mismatch is identified based at least partially on a condition regarding at least one of the address of the first packet, the path identifier of the first packet, the first wireless link, the second wireless link, or any combination thereof. Claim 12 A method for wireless communications by a first access node of a wireless backhaul communication network, wherein the first wireless link is an inflow link or a wireless link control channel. Claim 13 A method for wireless communications by a first access node of a wireless backhaul communication network, wherein the second wireless link is an outflow link or a wireless link control channel. Claim 14 A method for wireless communications by a first access node of a wireless backhaul communication network, comprising, in claim 1, the step of receiving a second packet through the first wireless link; the step of identifying a destination address of the second packet; and the step of identifying a mismatch between the address of the first access node and the destination address. Claim 15 A method for wireless communications by a first access node of a wireless backhaul communication network, further comprising the step of transmitting the second packet through the second wireless link or the third wireless link based at least partially on the configuration indicating to perform packet forwarding when an address mismatch is identified in claim 14. Claim 16 A method for wireless communications by a first access node of a wireless backhaul communication network, wherein the configuration indicates to perform packet forwarding when an address mismatch is identified based at least partially on a condition regarding at least one of the address of the first packet, the path identifier of the first packet, the first wireless link, the second wireless link, the third wireless link, or any combination thereof. Claim 17 A method for wireless communications by a first access node of a wireless backhaul communication network, wherein the first wireless link is an inflow link or a wireless link control channel, in claim 16. Claim 18 A method for wireless communications by a first access node of a wireless backhaul communication network, wherein the second wireless link is an outflow link or a wireless link control channel. Claim 19 A method for wireless communications by a first access node of a wireless backhaul communication network, wherein, in claim 1, the configuration indicating that network coding is enabled for the packet flow is received at least partially based on a modification of the network topology. Claim 20 A method for wireless communications by a first access node of a wireless backhaul communication network, wherein the configuration indicating that network coding is enabled for the packet flow is received at least partially based on a wireless link failure report. Claim 21 A method for wireless communications by a first access node of a wireless backhaul communication network, wherein, in claim 1, the configuration indicating that network coding is enabled for the packet flow is received at least partially based on buffer status reporting indicating congestion. Claim 22 A method for wireless communications by a first access node of a wireless backhaul communication network, wherein the configuration indicating that network coding is enabled for the packet flow is received at least partially based on the establishment, release, or modification of a wireless link control channel. Claim 23 A method for wireless communications by a first access node of a wireless backhaul communication network, wherein the step of receiving the configuration comprises receiving wireless resource control signaling or application protocol signaling indicating the configuration. Claim 24 A method for wireless communications by a first access node of a wireless backhaul communication network, further comprising: a step of determining that the amount of data from one or more received packets of the packet flow satisfies a network coding threshold; and a step of performing a network encoding operation on the one or more received packets of the packet flow based at least partially on the fact that the network coding threshold is satisfied. Claim 25 A method for wireless communications by a first access node of a wireless backhaul communication network, wherein network encoding the first packet comprises performing a linear network encoding operation or a fountain encoding operation on the first packet. Claim 26 A method for wireless communications by a first access node of a wireless backhaul communication network, wherein, in claim 1, the method further comprises the step of network encoding a first portion of data of the packet flow comprising a first subset of packets of the packet flow to generate the first encoded packet, and the first subset of packets comprises the first packet. Claim 27 A method for wireless communications by a first access node of a wireless backhaul communication network, further comprising the step of network encoding a second portion of data of said packet flow, which includes a second subset of packets of said packet flow, in order to generate a second encoded packet. Claim 28 A method for wireless communications by a first access node of a wireless backhaul communication network, wherein, in claim 27, the second subset of the packets comprises at least one packet from the first subset of the packets. Claim 29 A method for wireless communications by a first access node of a wireless backhaul communication network, comprising: receiving from a central unit node of the wireless backhaul communication network a configuration indicating that network coding is enabled for a packet flow, wherein the packet flow returns data to a specific user equipment (UE); receiving a plurality of encoded packets of the packet flow through one or more wireless links from one or more access nodes of the wireless backhaul communication network; and transmitting a first packet among a plurality of packets restored by network decoding of the plurality of encoded packets through a first wireless link along a first path among a plurality of different paths, wherein the first packet includes a first path identifier. A method for wireless communications by a first access node of a wireless backhaul communication network, comprising the step of transmitting a second packet among the plurality of encoded packets restored by network decoding of the plurality of encoded packets through a second wireless link along a second path among the plurality of different paths, wherein the second packet includes a second path identifier. Claim 30 A method for wireless communications by a first access node of a wireless backhaul communication network, wherein the first path is different from the second path. Claim 31 A method for wireless communications by a first access node of a wireless backhaul communication network, wherein the step of receiving the configuration comprises receiving wireless resource control signaling or application protocol signaling indicating the configuration. Claim 32 A method for wireless communications by a first access node of a wireless backhaul communication network, wherein the step of receiving the plurality of encoded packets of the packet flow comprises: receiving a first encoded packet among the plurality of encoded packets including the first path identifier; and receiving a second encoded packet among the plurality of encoded packets including the second path identifier. Claim 33 A method for wireless communications by a first access node of a wireless backhaul communication network, wherein, in claim 32, the first path identifier is different from the second path identifier. Claim 34 A method for wireless communications by a first access node of a wireless backhaul communication network, wherein the step of receiving the plurality of encoded packets comprises: identifying a destination address of a first encoded packet among the plurality of encoded packets; identifying a mismatch between the address of the first access node and the destination address; and providing the first encoded packet for network decoding based at least partially on a condition in the configuration indicating that network decoding is performed when an address mismatch is identified. Claim 35 A method for wireless communications by a first access node of a wireless backhaul communication network, wherein, in claim 34, the condition is for the destination address, the path identifier of the first encoded packet, or both. Claim 36 A method for wireless communications by a first access node of a wireless backhaul communication network, further comprising: receiving an unencoded packet; identifying a mismatch between the address of the first access node and the destination address of the unencoded packet; and transmitting the unencoded packet through an outflow wireless link or a wireless link control channel based at least partially on conditions in the configuration indicating to perform packet forwarding when an address mismatch is identified. Claim 37 A method for wireless communications by a first access node of a wireless backhaul communication network, wherein, in claim 36, the condition is for the destination address, the path identifier of the unencoded packet, or both. Claim 38 A method for wireless communications by a first access node of a wireless backhaul communication network, wherein network decoding of the plurality of encoded packets comprises performing a linear network decoding operation or a fountain decoding operation on the plurality of encoded packets. Claim 39 A method for wireless communications by a first access node of a wireless backhaul communication network, further comprising the step of transmitting a feedback message through a fourth wireless link indicating whether network decoding of the plurality of encoded packets for restoring the plurality of packets is successful or unsuccessful. Claim 40 A method for wireless communications by a central entity node of a wireless backhaul communication network, comprising: identifying an event to trigger the activation of network coding functionality for a packet flow by a first access node of the wireless backhaul communication network, wherein the packet flow returns data for a specific user equipment (UE); and transmitting a configuration indicating that network coding is activated for the packet flow to the first access node. Claim 41 A method for wireless communications by a central entity node of a wireless backhaul communication network, wherein the step of transmitting the configuration comprises the step of transmitting the configuration indicating a path selection function for distributing encoded packets between a plurality of different paths. Claim 42 A method for wireless communications by a central entity node of a wireless backhaul communication network, wherein, in claim 41, the path selection function indicates to distribute encoded packets uniformly or non-uniformly among the plurality of different paths. Claim 43 A method for wireless communications by a central entity node of a wireless backhaul communication network, wherein, in claim 40, the step of transmitting the configuration includes the step of transmitting the configuration indicating to perform network coding when an address mismatch is identified. Claim 44 A method for wireless communications by a central entity node of a wireless backhaul communication network, wherein, in claim 43, the configuration indicates to perform network coding when an address mismatch is identified based at least partially on a condition regarding at least one of the address of a packet of the packet flow, the path identifier of the packet, a first wireless link, a second wireless link, or any combination thereof. Claim 45 A method for wireless communications by a central entity node of a wireless backhaul communication network, wherein the first wireless link is an inflow link or a wireless link control channel, in the 44th paragraph. Claim 46 A method for wireless communications by a central entity node of a wireless backhaul communication network, wherein the second wireless link is an outflow link or a wireless link control channel, in the 44th paragraph. Claim 47 A method for wireless communications by a central entity node of a wireless backhaul communication network, wherein, in claim 40, the step of transmitting the configuration includes the step of transmitting the configuration indicating to perform packet forwarding when an address mismatch is identified. Claim 48 A method for wireless communications by a central entity node of a wireless backhaul communication network, wherein the configuration indicates to perform packet forwarding when an address mismatch is identified based at least partially on a condition regarding at least one of the address of a packet of the packet flow, a path identifier of the packet, a first wireless link, a second wireless link, or any combination thereof. Claim 49 A method for wireless communications by a central entity node of a wireless backhaul communication network, wherein the first wireless link is an inflow link or a wireless link control channel, in claim 48. Claim 50 In claim 48, a method for wireless communications by a central entity node of a wireless backhaul communication network, wherein the second wireless link is an outflow link or a wireless link control channel. Claim 51 A method for wireless communications by a central entity node of a wireless backhaul communication network, wherein, in claim 40, the step of identifying the event comprises identifying the event based at least partially on a modification of the network topology of the wireless backhaul communication network. Claim 52 A method for wireless communications by a central entity node of a wireless backhaul communication network, wherein, in claim 40, the step of identifying the event comprises identifying the event based at least partially on receiving a wireless link failure report. Claim 53 A method for wireless communications by a central entity node of a wireless backhaul communication network, wherein the step of identifying the event comprises identifying the event at least partially based on receiving buffer status reporting indicating congestion at one or more access nodes of the wireless backhaul communication network. Claim 54 A method for wireless communications by a central entity node of a wireless backhaul communication network, wherein the step of identifying the event comprises identifying the event based at least partially on the establishment, release, or modification of a wireless link control channel at one or more access nodes of the wireless backhaul communication network. Claim 55 A method for wireless communications by a central entity node of a wireless backhaul communication network, wherein, in claim 40, the step of identifying the event comprises identifying the event based at least partially on the elapsed time period. Claim 56 A method for wireless communications by a central entity node of a wireless backhaul communication network, wherein the step of transmitting the configuration comprises transmitting a wireless resource control signaling or an application protocol signaling indicating the configuration. Claim 57 An apparatus for wireless communications by a first access node of a wireless backhaul communication network, comprising: means for receiving, from a central unit node of the wireless backhaul communication network, a configuration indicating that network coding is enabled for a packet flow, wherein the packet flow returns data to a specific user equipment (UE); means for receiving a first packet of the packet flow via a first wireless link from a second access node of the wireless backhaul communication network; and means for transmitting a first encoded packet generated at least partially based on network encoding the first packet via a second wireless link. Claim 58 A device for wireless communications by a first access node of a wireless backhaul communication network, comprising: means for receiving, from a central unit node of the wireless backhaul communication network, a configuration indicating that network coding is enabled for a packet flow, wherein the packet flow returns data to a specific user equipment (UE); means for receiving a plurality of encoded packets of the packet flow through one or more wireless links from one or more access nodes of the wireless backhaul communication network; and means for transmitting a first packet among a plurality of packets restored by network decoding of the plurality of encoded packets through a first wireless link along a first path among a plurality of different paths, wherein the first packet includes a first path identifier. An apparatus for wireless communications by a first access node of a wireless backhaul communication network, comprising: a means for transmitting a second packet among a plurality of encoded packets restored by network decoding of the plurality of encoded packets through a second wireless link along a second path among the plurality of different paths, wherein the second packet includes a second path identifier. Claim 59 A device for wireless communications by a central entity node of a wireless backhaul communication network, comprising: means for identifying an event to trigger the activation of network coding functionality for a packet flow by a first access node of the wireless backhaul communication network, wherein the packet flow returns data for a specific user equipment (UE); and means for transmitting to the first access node a configuration indicating that network coding is activated for the packet flow.

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