WO2021159440A1

WO2021159440A1 - Techniques for determining a degree distribution in a multi-hop network

Info

Publication number: WO2021159440A1
Application number: PCT/CN2020/075204
Authority: WO
Inventors: Kangqi LIU; Changlong Xu; Liangming WU; Jian Li; Hao Xu
Original assignee: Qualcomm Incorporated
Priority date: 2020-02-14
Filing date: 2020-02-14
Publication date: 2021-08-19

Abstract

Methods, systems, and devices for wireless communications are described. An input node of a multi-hop network may determine a first hop degree distribution based on a desired last hop degree distribution at an output node. The input node may be an integrated access and backhaul (IAB) network node, such as a user equipment (UE), a base station, an IAB relay node, or another wireless device. The input node may encode packets using a fountain code (e. g. a Luby transform (LT) code, a rapid tornado (Raptor) code, etc. ), where encoding the packets may be based on the determined first hop degree distribution. In some examples, the input node may further determine the first hop degree distribution based on parameters of the multi-hop network. The described techniques may enable IAB network nodes to improve efficiency and reliability of communications in a multi-hop network by increasing the probability of successfully decoding transmitted packets.

Description

TECHNIQUES FOR DETERMINING A DEGREE DISTRIBUTION IN A MULTI-HOP NETWORK

TECHNICAL FIELD

The following relates generally to wireless communications and more specifically to techniques for determining a degree distribution in a multi-hop network.

BACKGROUND

Wireless communications systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power) . Examples of such multiple-access systems include fourth generation (4G) systems such as Long Term Evolution (LTE) systems, LTE-Advanced (LTE-A) systems, or LTE-A Pro systems, and fifth generation (5G) systems which may be referred to as New Radio (NR) systems. 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 communications system may include one or more base stations or one or more network access nodes, each simultaneously supporting communication for multiple communication devices, which may be otherwise known as user equipment (UE) .

Packets may be exchanged between network nodes to transmit information in wireless communications systems. Packets may be encoded to improve the reliability of the transmitted information. In some cases, encoded packets may provide redundancy, which may be used to correct errors that result from the transmission environment (e.g., path loss, obstacles, etc. ) . Some examples of encoding algorithms with error correcting codes include fountain codes, such as Luby transform (LT) codes or rapid tornado (Raptor) codes.

SUMMARY

The described techniques relate to improved methods, systems, devices, and apparatuses that support techniques for determining a degree distribution in a multi-hop network. Generally, the described techniques provide for enabling an input node of a multi-hop network to determine a first hop degree distribution based on a desired last hop degree distribution at an output node. The input node may be an integrated access and backhaul (IAB) network node, such as a user equipment (UE) , a base station, an IAB relay node, or another wireless device. The input node may encode packets using a fountain code, where encoding the packets may be based on the determined first hop degree distribution. In some examples, the input node may further determine the first hop degree distribution based on parameters of the multi-hop network, including a quantity of hops in the multi-hop network, a quantity of stages between hops, a respective quantity of nodes in each stage, a respective capacity of each link between nodes, a respective erasure probability of each link between nodes, etc. The techniques described herein may enable IAB network nodes to improve efficiency and reliability of communications in the multi-hop network by increasing the probability of successfully decoding transmitted information.

A method of wireless communications at an input node of a multi-hop network is described. The method may include identifying a last hop fountain code degree distribution for an output node of the multi-hop network, where the last hop fountain code degree distribution is identified based on a target decoding success probability at the output node, determining a first hop fountain code degree distribution at the input node based on the last hop fountain code degree distribution and a quantity of hops in the multi-hop network, encoding a set of packets at the input node according to a fountain code and based on determining the first hop fountain code degree distribution, and transmitting the set of packets to one or more nodes of the multi-hop network via a first hop in the multi-hop network.

An apparatus for wireless communications at an input node of a multi-hop network is described. The apparatus may include a processor, memory coupled with the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to identify a last hop fountain code degree distribution for an output node of the multi-hop network, where the last hop fountain code degree distribution is identified based on a target decoding success probability at the output node, determine a first hop fountain code degree distribution at the input node based on the last hop fountain code degree distribution and a quantity of hops in the multi-hop network, encode a set of packets at the input node according to a fountain code and based on determining the first hop fountain code degree distribution, and transmit the set of packets to one or more nodes of the multi-hop network via a first hop in the multi-hop network.

Another apparatus for wireless communications at an input node of a multi-hop network is described. The apparatus may include means for identifying a last hop fountain code degree distribution for an output node of the multi-hop network, where the last hop fountain code degree distribution is identified based on a target decoding success probability at the output node, determining a first hop fountain code degree distribution at the input node based on the last hop fountain code degree distribution and a quantity of hops in the multi-hop network, encoding a set of packets at the input node according to a fountain code and based on determining the first hop fountain code degree distribution, and transmitting the set of packets to one or more nodes of the multi-hop network via a first hop in the multi-hop network.

A non-transitory computer-readable medium storing code for wireless communications at an input node of a multi-hop network is described. The code may include instructions executable by a processor to identify a last hop fountain code degree distribution for an output node of the multi-hop network, where the last hop fountain code degree distribution is identified based on a target decoding success probability at the output node, determine a first hop fountain code degree distribution at the input node based on the last hop fountain code degree distribution and a quantity of hops in the multi-hop network, encode a set of packets at the input node according to a fountain code and based on determining the first hop fountain code degree distribution, and transmit the set of packets to one or more nodes of the multi-hop network via a first hop in the multi-hop network.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining a quantity of stages in the multi-hop network based on the quantity of hops in the multi-hop network, where a first stage includes the one or more nodes, and where the first hop includes one or more links between the input node and the one or more nodes of the first stage, and determining a respective quantity of nodes of each stage in the multi-hop network, where determining the first hop fountain code degree distribution at the input node may be further based on the quantity of stages and the respective quantity of nodes of each stage in the multi-hop network.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining an intermediate hop fountain code degree distribution for a node of a stage in the multi-hop network, where determining the first hop fountain code degree distribution at the input node may be further based on determining the intermediate hop fountain code degree distribution.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining a respective erasure probability of each link in the multi-hop network, and determining a respective capacity of each link in the multi-hop network, where determining the first hop fountain code degree distribution at the input node may be further based on the respective erasure probability and the respective capacity of each link in the multi-hop network.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the respective erasure probability may be the same for each link in the multi-hop network, and the respective capacity may be the same for each link in the multi-hop network.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, determining the first hop fountain code degree distribution may include operations, features, means, or instructions for transmitting an indication of the last hop fountain code degree distribution to a network device, and receiving an indication of the first hop fountain code degree distribution based on the transmitting.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first hop fountain code degree distribution may have a first length, and the last hop fountain code degree distribution may have a second length that may be less than or equal to the first length.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first hop fountain code degree distribution may be different from the last hop fountain code degree distribution.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the input node or the output node includes an integrated access and backhaul relay node.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the last hop fountain code degree distribution includes an ideal soliton distribution, a robust soliton distribution, or a combination thereof.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the fountain code includes a Luby transform (LT) code, a rapid tornado (Raptor) code, or both.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example of a wireless communications system that supports techniques for determining a degree distribution in a multi-hop network in accordance with aspects of the present disclosure.

FIGs. 3 and 4 illustrate examples of a multi-hop network that supports techniques for determining a degree distribution in accordance with aspects of the present disclosure.

FIG. 2 illustrates an example of a encoding scheme that supports techniques for determining a degree distribution in a multi-hop network in accordance with aspects of the present disclosure.

FIGs. 5 and 6 show block diagrams of devices that support techniques for determining a degree distribution in a multi-hop network in accordance with aspects of the present disclosure.

FIG. 7 shows a block diagram of a communications manager that supports techniques for determining a degree distribution in a multi-hop network in accordance with aspects of the present disclosure.

FIG. 8 shows a diagram of a system including a user equipment (UE) that supports techniques for determining a degree distribution in a multi-hop network in accordance with aspects of the present disclosure.

FIG. 9 shows a diagram of a system including a base station that supports techniques for determining a degree distribution in a multi-hop network in accordance with aspects of the present disclosure.

FIGs. 10 and 11 show flowcharts illustrating methods that support techniques for determining a degree distribution in a multi-hop network in accordance with aspects of the present disclosure.

DETAILED DESCRIPTION

Some wireless communication systems, such as fifth generation (5G) systems which may be referred to as New Radio (NR) systems, may include network nodes that exchange packets via integrated access and backhaul (IAB) links. A network node, such as a user equipment (UE) , a base station, an IAB relay node, or another wireless device, may encode packets before transmission to improve reliability of a destination node successfully receiving the transmitted information. In some cases, encoded packets may provide redundancy, which may be used to correct errors that result from the transmission environment (e.g., path loss, obstacles, etc. ) .

Some examples of encoding algorithms with error correcting codes include fountain codes, such as Luby transform (LT) codes or rapid tornado (Raptor) codes. A fountain code may be an example of a rateless code, where a set of source symbols (e.g., K symbols) may be encoded as any quantity of encoding symbols (e.g., a quantity of symbols greater than K symbols) . Encoding the source symbols may include combining one or more source symbols into each encoding symbol. The encoding may include using a degree distribution, where the degree distribution represents a probability mass function of a set of degrees d _i (e.g., d ₁, d ₂, d ₃, etc. ) . The probability of randomly selecting a degree d _i (i.e., a degree with index i) from the degree distribution may be represented by ρ (i) . In the encoding process, the degree d _i may represent the quantity of source symbols which may be combined into a given encoding symbol.

The encoding symbols may be transmitted as a set of encoded packets from a first node (which may be referred to as an input node) of a network to a second node (which may be referred to as an output node) . In some examples, the network may be a multi-hop network, where the encoded packets are relayed to the output node via one or more nodes of the network (which may be referred to intermediate nodes) . In some examples, one or more encoded packets may be lost based on the transmission environment. The output node may receive a subset of encoded packets via the multi-hop network. Based on the encoding and combining, the output node may decode the set of source symbols from the subset of encoded packets despite the packet loss.

In some examples, the probability of the output node successfully decoding the source symbols may be based on the degree distribution used in the encoding process. For example, the decoding success probability may be based on a degree distribution Ω ^r associated with the packets received at the output node, which may in turn be based on the original degree distribution Ω used in the encoding process. In some examples, it may be advantageous to configure the original degree distribution Ω such that the final degree distribution Ω ^r is a desired distribution , such as an ideal soliton distribution or a robust soliton distribution, which may increase the decoding success probability.

According to the techniques described herein, an input node of a multi-hop network may determine a first hop degree distribution for encoding transmissions based on a desired last hop degree distribution at an output node. The input node may be an IAB network node, such as a UE, a base station, an IAB relay node, or another wireless device. The input node may encode packets using a fountain code, where encoding the packets may be based on the determined first degree distribution. In some examples, the input node may further determine the first hop degree distribution based on parameters of the multi-hop network, including a quantity of hops in the multi-hop network, a quantity of stages between hops, a respective quantity of nodes in each stage, a respective capacity of each link between nodes, a respective erasure probability of each link between nodes, etc. The techniques described herein may enable network nodes to improve efficiency and reliability of communications in the multi-hop network by increasing the probability of successfully decoding transmitted information.

Aspects of the disclosure are initially described in the context of wireless communications systems. Example multi-hop networks and an example encoding scheme illustrating aspects of the discussed techniques are then described. Aspects of the disclosure are further illustrated by and described with reference to apparatus diagrams, system diagrams, and flowcharts that relate to techniques for determining a degree distribution in a multi-hop network.

FIG. 1 illustrates an example of a wireless communications system 100 that supports techniques for determining a degree distribution in a multi-hop network in accordance with aspects of the present disclosure. The wireless communications system 100 may include one or more base stations 105, one or more UEs 115, and a core network 130. In some examples, the wireless communications system 100 may be a Long Term Evolution (LTE) network, an LTE-Advanced (LTE-A) network, an LTE-A Pro network, or a New Radio (NR) network. In some examples, the wireless communications system 100 may support enhanced broadband communications, ultra-reliable (e.g., mission critical) communications, low latency communications, communications with low-cost and low-complexity devices, or any combination thereof.

The base stations 105 may be dispersed throughout a geographic area to form the wireless communications system 100 and may be devices in different forms or having different capabilities. The base stations 105 and the UEs 115 may wirelessly communicate via one or more communication links 125. Each base station 105 may provide a coverage area 110 over which the UEs 115 and the base station 105 may establish one or more communication links 125. The coverage area 110 may be an example of a geographic area over which a base station 105 and a UE 115 may support the communication of signals according to one or more radio access technologies.

The UEs 115 may be dispersed throughout a coverage area 110 of the wireless communications system 100, and each UE 115 may be stationary, or mobile, or both at different times. The UEs 115 may be devices in different forms or having different capabilities. Some example UEs 115 are illustrated in FIG. 1. The UEs 115 described herein may be able to communicate with various types of devices, such as other UEs 115, the base stations 105, or network equipment (e.g., core network nodes, relay devices, IAB nodes, or other network equipment) , as shown in FIG. 1.

The base stations 105 may communicate with the core network 130, or with one another, or both. For example, the base stations 105 may interface with the core network 130 through one or more backhaul links 120 (e.g., via an S1, N2, N3, or other interface) . The base stations 105 may communicate with one another over the backhaul links 120 (e.g., via an X2, Xn, or other interface) either directly (e.g., directly between base stations 105) , or indirectly (e.g., via core network 130) , or both. In some examples, the backhaul links 120 may be or include one or more wireless links.

One or more of the base stations 105 described herein may include or may be referred to by a person having ordinary skill in the art as a base transceiver station, a radio base station, an access point, a radio transceiver, a NodeB, an eNodeB (eNB) , a next-generation NodeB or a giga-NodeB (either of which may be referred to as a gNB) , a Home NodeB, a Home eNodeB, or other suitable terminology.

A UE 115 may include or may be referred to as a mobile device, a wireless device, a remote device, a handheld device, or a subscriber device, or some other suitable terminology, where the “device” may also be referred to as a unit, a station, a terminal, or a client, among other examples. A UE 115 may also include or may be referred to as a personal electronic device such as a cellular phone, a personal digital assistant (PDA) , a multimedia/entertainment device (e.g., a radio, a MP3 player, a video device, etc. ) , a camera, a gaming device, a navigation/positioning device (e.g., GNSS (global navigation satellite system) devices based on, for example, GPS (global positioning system) , Beidou, GLONASS, or Galileo, a terrestrial-based device, etc. ) , a tablet computer, a laptop computer, a netbook, a smartbook, a personal computer, a smart device, a wearable device (e.g., a smart watch, smart clothing, smart glasses, virtual reality goggles, a smart wristband, smart jewelry (e.g., a smart ring, a smart bracelet) ) , a drone, a robot/robotic device, a vehicle, a vehicular device, a meter (e.g., parking meter, electric meter, gas meter, water meter) , a monitor, a gas pump, an appliance (e.g., kitchen appliance, washing machine, dryer) , a location tag, a medical/healthcare device, an implant, a sensor/actuator, a display, or any other suitable device configured to communicate via a wireless or wired medium. In some examples, a UE 115 may include or be referred to as a wireless local loop (WLL) station, an Internet of Things (IoT) device, an Internet of Everything (IoE) device, or a machine type communications (MTC) device, among other examples, which may be implemented in various objects such as appliances, or vehicles, meters, among other examples.

Some UEs 115, such as MTC or IoT devices, may be low cost or low complexity devices, and may provide for automated communication between machines (e.g., via Machine-to-Machine (M2M) communication) . M2M communication or MTC may refer to data communication technologies that allow devices to communicate with one another or a base station 105 without human intervention. In some examples, M2M communication or MTC may include communications from devices that integrate sensors or meters to measure or capture information and relay that information to a central server or application program that can make use of the information or present the information to humans interacting with the program or application. Some UEs 115 may be designed to collect information or enable automated behavior of machines. Examples of applications for MTC devices include smart metering, inventory monitoring, water level monitoring, equipment monitoring, healthcare monitoring, wildlife monitoring, weather and geological event monitoring, fleet management and tracking, remote security sensing, physical access control, and transaction-based business charging. In an aspect, techniques disclosed herein may be applicable to MTC or IoT UEs. MTC or IoT UEs may include MTC/enhanced MTC (eMTC, also referred to as CAT-M, Cat M1) UEs, narrowband IoT (NB-IoT) (also referred to as CAT NB1) UEs, as well as other types of UEs. eMTC and NB-IoT may refer to future technologies that may evolve from or may be based on these technologies. For example, eMTC may include FeMTC (further eMTC) , eFeMTC (enhanced further eMTC) , mMTC (massive MTC) , etc., and NB-IoT may include eNB-IoT (enhanced NB-IoT) , FeNB-IoT (further enhanced NB-IoT) , etc.

The UEs 115 described herein may be able to communicate with various types of devices, such as other UEs 115 that may sometimes act as relays as well as the base stations 105 and the network equipment including macro eNBs or gNBs, small cell eNBs or gNBs, or relay base stations, among other examples, as shown in FIG. 1.

The UEs 115 and the base stations 105 may wirelessly communicate with one another via one or more communication links 125 over one or more carriers. The term “carrier” may refer to a set of radio frequency spectrum resources having a defined physical layer structure for supporting the communication links 125. For example, a carrier used for a communication link 125 may include a portion of a radio frequency spectrum band (e.g., a bandwidth part (BWP) ) that is operated according to one or more physical layer channels for a given radio access technology (e.g., LTE, LTE-A, LTE-A Pro, NR) . Each physical layer channel may carry acquisition signaling (e.g., synchronization signals, system information) , control signaling that coordinates operation for the carrier, user data, or other signaling. The wireless communications system 100 may support communication with a UE 115 using carrier aggregation or multi-carrier operation. A UE 115 may be configured with multiple downlink component carriers and one or more uplink component carriers according to a carrier aggregation configuration. Carrier aggregation may be used with both frequency division duplexing (FDD) and time division duplexing (TDD) component carriers.

Signal waveforms transmitted over a carrier may be made up of multiple subcarriers (e.g., using multi-carrier modulation (MCM) techniques such as orthogonal frequency division multiplexing (OFDM) or discrete Fourier transform spread OFDM (DFT-S-OFDM) ) . In a system employing MCM techniques, a resource element may consist of one symbol period (e.g., a duration of one modulation symbol) and one subcarrier, where the symbol period and subcarrier spacing are inversely related. The number of bits carried by each resource element may depend on the modulation scheme (e.g., the order of the modulation scheme, the coding rate of the modulation scheme, or both) . Thus, the more resource elements that a UE 115 receives and the higher the order of the modulation scheme, the higher the data rate may be for the UE 115. A wireless communications resource may refer to a combination of a radio frequency spectrum resource, a time resource, and a spatial resource (e.g., spatial layers or beams) , and the use of multiple spatial layers may further increase the data rate or data integrity for communications with a UE 115.

The time intervals for the base stations 105 or the UEs 115 may be expressed in multiples of a basic time unit which may, for example, refer to a sampling period of T _s= 1/ (Δf _max·N _f) seconds, where Δf _max may represent the maximum supported subcarrier spacing, and N _f may represent the maximum supported discrete Fourier transform (DFT) size. Time intervals of a communications resource may be organized according to radio frames each having a specified duration (e.g., 10 milliseconds (ms) ) . Each radio frame may be identified by a system frame number (SFN) (e.g., ranging from 0 to 1023) .

Each frame may include multiple consecutively numbered subframes or slots, and each subframe or slot may have the same duration. In some examples, a frame may be divided (e.g., in the time domain) into subframes, and each subframe may be further divided into a number of slots. Alternatively, each frame may include a variable number of slots, and the number of slots may depend on subcarrier spacing. Each slot may include a number of symbol periods (e.g., depending on the length of the cyclic prefix prepended to each symbol period) . In some wireless communications systems 100, a slot may further be divided into multiple mini-slots containing one or more symbols. Excluding the cyclic prefix, each symbol period may contain one or more (e.g., N _f) sampling periods. The duration of a symbol period may depend on the subcarrier spacing or frequency band of operation.

A subframe, a slot, a mini-slot, or a symbol may be the smallest scheduling unit (e.g., in the time domain) of the wireless communications system 100 and may be referred to as a transmission time interval (TTI) . In some examples, the TTI duration (e.g., the number of symbol periods in a TTI) may be variable. Additionally or alternatively, the smallest scheduling unit of the wireless communications system 100 may be dynamically selected (e.g., in bursts of shortened TTIs (sTTIs) ) .

Physical channels may be multiplexed on a carrier according to various techniques. A physical control channel and a physical data channel may be multiplexed on a downlink carrier, for example, using one or more of time division multiplexing (TDM) techniques, frequency division multiplexing (FDM) techniques, or hybrid TDM-FDM techniques. A control region (e.g., a control resource set (CORESET) ) for a physical control channel may be defined by a number of symbol periods and may extend across the system bandwidth or a subset of the system bandwidth of the carrier. One or more control regions (e.g., CORESETs) may be configured for a set of the UEs 115. For example, one or more of the UEs 115 may monitor or search control regions for control information according to one or more search space sets, and each search space set may include one or multiple control channel candidates in one or more aggregation levels arranged in a cascaded manner. An aggregation level for a control channel candidate may refer to a number of control channel resources (e.g., control channel elements (CCEs) ) associated with encoded information for a control information format having a given payload size. Search space sets may include common search space sets configured for sending control information to multiple UEs 115 and UE-specific search space sets for sending control information to a specific UE 115.

Each base station 105 may provide communication coverage via one or more cells, for example a macro cell, a small cell, a hot spot, or other types of cells, or any combination thereof. The term “cell” may refer to a logical communication entity used for communication with a base station 105 (e.g., over a carrier) and may be associated with an identifier for distinguishing neighboring cells (e.g., a physical cell identifier (PCID) , a virtual cell identifier (VCID) , or others) . In some examples, a cell may also refer to a geographic coverage area 110 or a portion of a geographic coverage area 110 (e.g., a sector) over which the logical communication entity operates. Such cells may range from smaller areas (e.g., a structure, a subset of structure) to larger areas depending on various factors such as the capabilities of the base station 105. For example, a cell may be or include a building, a subset of a building, or exterior spaces between or overlapping with geographic coverage areas 110, among other examples.

A macro cell generally covers a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by the UEs 115 with service subscriptions with the network provider supporting the macro cell. A small cell may be associated with a lower-powered base station 105, as compared with a macro cell, and a small cell may operate in the same or different (e.g., licensed, unlicensed) frequency bands as macro cells. Small cells may provide unrestricted access to the UEs 115 with service subscriptions with the network provider or may provide restricted access to the UEs 115 having an association with the small cell (e.g., the UEs 115 in a closed subscriber group (CSG) , the UEs 115 associated with users in a home or office) . A base station 105 may support one or multiple cells and may also support communications over the one or more cells using one or multiple component carriers.

In some examples, a carrier may support multiple cells, and different cells may be configured according to different protocol types (e.g., MTC, NB-IoT, enhanced mobile broadband (eMBB) ) that may provide access for different types of devices.

In some examples, a base station 105 may be movable and therefore provide communication coverage for a moving geographic coverage area 110. In some examples, different geographic coverage areas 110 associated with different technologies may overlap, but the different geographic coverage areas 110 may be supported by the same base station 105. In other examples, the overlapping geographic coverage areas 110 associated with different technologies may be supported by different base stations 105. The wireless communications system 100 may include, for example, a heterogeneous network in which different types of the base stations 105 provide coverage for various geographic coverage areas 110 using the same or different radio access technologies.

Some UEs 115, such as MTC or IoT devices, may be low cost or low complexity devices and may provide for automated communication between machines (e.g., via Machine-to-Machine (M2M) communication) . M2M communication or MTC may refer to data communication technologies that allow devices to communicate with one another or a base station 105 without human intervention. In some examples, M2M communication or MTC may include communications from devices that integrate sensors or meters to measure or capture information and relay such information to a central server or application program that makes use of the information or presents the information to humans interacting with the application program. Some UEs 115 may be designed to collect information or enable automated behavior of machines or other devices. Examples of applications for MTC devices include smart metering, inventory monitoring, water level monitoring, equipment monitoring, healthcare monitoring, wildlife monitoring, weather and geological event monitoring, fleet management and tracking, remote security sensing, physical access control, and transaction-based business charging.

The wireless communications system 100 may be configured to support ultra-reliable communications or low-latency communications, or various combinations thereof. For example, the wireless communications system 100 may be configured to support ultra-reliable low-latency communications (URLLC) or mission critical communications. The UEs 115 may be designed to support ultra-reliable, low-latency, or critical functions (e.g., mission critical functions) . Ultra-reliable communications may include private communication or group communication and may be supported by one or more mission critical services such as mission critical push-to-talk (MCPTT) , mission critical video (MCVideo) , or mission critical data (MCData) . Support for mission critical functions may include prioritization of services, and mission critical services may be used for public safety or general commercial applications. The terms ultra-reliable, low-latency, mission critical, and ultra-reliable low-latency may be used interchangeably herein.

In some examples, a UE 115 may also be able to communicate directly with other UEs 115 over a device-to-device (D2D) communication link 135 (e.g., using a peer-to-peer (P2P) or D2D protocol) . One or more UEs 115 utilizing D2D communications may be within the geographic coverage area 110 of a base station 105. Other UEs 115 in such a group may be outside the geographic coverage area 110 of a base station 105 or be otherwise unable to receive transmissions from a base station 105. In some examples, groups of the UEs 115 communicating via D2D communications may utilize a one-to-many (1: M) system in which each UE 115 transmits to every other UE 115 in the group. In some examples, a base station 105 facilitates the scheduling of resources for D2D communications. In other cases, D2D communications are carried out between the UEs 115 without the involvement of a base station 105.

The core network 130 may provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. The core network 130 may be an evolved packet core (EPC) or 5G core (5GC) , which may include at least one control plane entity that manages access and mobility (e.g., a mobility management entity (MME) , an access and mobility management function (AMF) ) and at least one user plane entity that routes packets or interconnects to external networks (e.g., a serving gateway (S-GW) , a Packet Data Network (PDN) gateway (P-GW) , or a user plane function (UPF) ) . The control plane entity may manage non-access stratum (NAS) functions such as mobility, authentication, and bearer management for the UEs 115 served by the base stations 105 associated with the core network 130. User IP packets may be transferred through the user plane entity, which may provide IP address allocation as well as other functions. The user plane entity may be connected to the network operators IP services 150. The operators IP services 150 may include access to the Internet, Intranet (s) , an IP Multimedia Subsystem (IMS) , or a Packet-Switched Streaming Service.

Some of the network devices, such as a base station 105, may include subcomponents such as an access network entity 140, which may be an example of an access node controller (ANC) . Each access network entity 140 may communicate with the UEs 115 through one or more other access network transmission entities 145, which may be referred to as radio heads, smart radio heads, or transmission/reception points (TRPs) . Each access network transmission entity 145 may include one or more antenna panels. In some configurations, various functions of each access network entity 140 or base station 105 may be distributed across various network devices (e.g., radio heads and ANCs) or consolidated into a single network device (e.g., a base station 105) .

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

The wireless communications system 100 may also operate in a super high frequency (SHF) region using frequency bands from 3 GHz to 30 GHz, also known as the centimeter band, or in an extremely high frequency (EHF) region of the spectrum (e.g., from 30 GHz to 300 GHz) , also known as the millimeter band. In some examples, the wireless communications system 100 may support millimeter wave (mmW) communications between the UEs 115 and the base stations 105, and EHF antennas of the respective devices may be smaller and more closely spaced than UHF antennas. In some examples, this may facilitate use of antenna arrays within a device. The propagation of EHF transmissions, however, may be subject to even greater atmospheric attenuation and shorter range than SHF or UHF transmissions. The techniques disclosed herein may be employed across transmissions that use one or more different frequency regions, and designated use of bands across these frequency regions may differ by country or regulating body.

The wireless communications system 100 may utilize both licensed and unlicensed radio frequency spectrum bands. For example, the wireless communications system 100 may employ License Assisted Access (LAA) , LTE-Unlicensed (LTE-U) radio access technology, or NR technology in an unlicensed band such as the 5 GHz industrial, scientific, and medical (ISM) band. When operating in unlicensed radio frequency spectrum bands, devices such as the base stations 105 and the UEs 115 may employ carrier sensing for collision detection and avoidance. In some examples, operations in unlicensed bands may be based on a carrier aggregation configuration in conjunction with component carriers operating in a licensed band (e.g., LAA) . Operations in unlicensed spectrum may include downlink transmissions, uplink transmissions, P2P transmissions, or D2D transmissions, among other examples.

A base station 105 or a UE 115 may be equipped with multiple antennas, which may be used to employ techniques such as transmit diversity, receive diversity, multiple-input multiple-output (MIMO) communications, or beamforming. The antennas of a base station 105 or a UE 115 may be located within one or more antenna arrays or antenna panels, which may support MIMO operations or transmit or receive beamforming. For example, one or more base station antennas or antenna arrays may be co-located at an antenna assembly, such as an antenna tower. In some examples, antennas or antenna arrays associated with a base station 105 may be located in diverse geographic locations. A base station 105 may have an antenna array with a number of rows and columns of antenna ports that the base station 105 may use to support beamforming of communications with a UE 115. Likewise, a UE 115 may have one or more antenna arrays that may support various MIMO or beamforming operations. Additionally or alternatively, an antenna panel may support radio frequency beamforming for a signal transmitted via an antenna port.

The base stations 105 or the UEs 115 may use MIMO communications to exploit multipath signal propagation and increase the spectral efficiency by transmitting or receiving multiple signals via different spatial layers. Such techniques may be referred to as spatial multiplexing. The multiple signals may, for example, be transmitted by the transmitting device via different antennas or different combinations of antennas. Likewise, the multiple signals may be received by the receiving device via different antennas or different combinations of antennas. Each of the multiple signals may be referred to as a separate spatial stream and may carry bits associated with the same data stream (e.g., the same codeword) or different data streams (e.g., different codewords) . Different spatial layers may be associated with different antenna ports used for channel measurement and reporting. MIMO techniques include single-user MIMO (SU-MIMO) , where multiple spatial layers are transmitted to the same receiving device, and multiple-user MIMO (MU-MIMO) , where multiple spatial layers are transmitted to multiple devices.

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

The wireless communications system 100 may be a packet-based network that operates according to a layered protocol stack. In the user plane, communications at the bearer or Packet Data Convergence Protocol (PDCP) layer may be IP-based. A Radio Link Control (RLC) layer may perform packet segmentation and reassembly to communicate over logical channels. A Medium Access Control (MAC) layer may perform priority handling and multiplexing of logical channels into transport channels. The MAC layer may also use error detection techniques, error correction techniques, or both to support retransmissions at the MAC layer to improve link efficiency. In the control plane, the Radio Resource Control (RRC) protocol layer may provide establishment, configuration, and maintenance of an RRC connection between a UE 115 and a base station 105 or a core network 130 supporting radio bearers for user plane data. At the physical layer, transport channels may be mapped to physical channels.

The UEs 115 and the base stations 105 may support retransmissions of data to increase the likelihood that data is received successfully. Hybrid automatic repeat request (HARQ) feedback is one technique for increasing the likelihood that data is received correctly over a communication link 125. HARQ may include a combination of error detection (e.g., using a cyclic redundancy check (CRC) ) , forward error correction (FEC) , and retransmission (e.g., automatic repeat request (ARQ) ) . HARQ may improve throughput at the MAC layer in poor radio conditions (e.g., low signal-to-noise conditions) . In some examples, a device may support same-slot HARQ feedback, where the device may provide HARQ feedback in a specific slot for data received in a previous symbol in the slot. In other cases, the device may provide HARQ feedback in a subsequent slot, or according to some other time interval.

In some examples, the wireless communications system 100 may include a multi-hop network for exchanging information between network nodes, which may include a UE 115, a base station 105, an IAB relay node, etc. For example, the multi-hop network may include one or more network nodes connected via backhaul links 120 or communication links 125 (which in some cases may be referred to as access links) . In some examples, UEs 115 or IAB relay nodes may be connected to network nodes (e.g., base stations 105) via backhaul links 120 to exchange information in the multi-hop network. An input node of the multi-hop network may determine a first hop degree distribution for encoding transmissions based on a desired last hop degree distribution at an output node. The input node may encode packets using a fountain code, where encoding the packets may be based on the determined first hop degree distribution. In some examples, the input node may further determine the first hop degree distribution based on parameters of the multi-hop network, including a quantity of hops in the multi-hop network, a quantity of stages between hops, a respective quantity of nodes in each stage, a respective capacity of each link between nodes, a respective erasure probability of each link between nodes, etc. The techniques described herein may enable network nodes to improve efficiency and reliability of communications in the multi-hop network by increasing the probability of successfully decoding transmitted information.

FIG. 2 illustrates an example of a encoding scheme 200 that supports techniques for determining a degree distribution in a multi-hop network in accordance with aspects of the present disclosure. In some examples, the encoding scheme 200 may implement aspects of wireless communication system 100. For example, the encoding scheme 200 may be associated with communications between IAB network nodes, where each IAB network node may be an IAB relay node, a UE 115, or a base station 105 as described herein.

The encoding scheme 200 may use Raptor coding to encode packets for transmission, for example via a multi-hop network. An IAB node (which may be referred to as an input node) may encode a set of source symbols 205 (e.g., a quantity K of source symbols 205) into a set of encoding symbols 225. The quantity of encoding symbols 225 may be greater than the quantity of source symbols 205 to improve a probability of successfully decoding the source symbols 205 at another IAB node (which may be referred to as an output node) . In some examples, the encoding scheme 200 may be rateless, where the quantity of encoding symbols 225 may have no upper limit.

The encoding scheme 200 may include a precoding process 210. In the precoding process 210, the input node may map one or more source symbols 205 to each of a set of intermediate symbols 215. The input node may generate a quantity of redundant intermediate symbols 215 (e.g., a quantity of intermediate symbols 215 in addition to a quantity K of intermediate symbols 215 directly mapped to the K source symbols 205) . In some examples, the redundant intermediate symbols 215 may include a quantity S of low-density parity-check (LDPC) symbols, where one or more copies (e.g., three copies) of each source symbol 205 may appear in each LDPC symbol. Additionally or alternatively, the redundant intermediate symbols 215 may include a quantity H of half symbols, where each half symbol may include ceil (H/2) source symbols 205, and where ceil (x) may represent a ceiling function mapping x to a least integer greater than or equal to x.

The encoding scheme 200 may include an LT coding process 220 following the precoding process 210. In the LT coding process 220, the input node may map the intermediate symbols 215 to the set of encoding symbols 225. The LT coding process 220 may employ a degree distribution Ω, where the degree distribution Ω represents a probability mass function of a set of degrees d _i (e.g., d ₁, d ₂, d ₃, etc. ) . The probability of randomly selecting a degree d _i (i.e., a degree with index i) from the degree distribution may be represented by ρ (i) . In the LT coding process 220, the degree d _i may represent the quantity of intermediate symbols 215 which the input node may combine into a given encoding symbol 225. For example, if the degree d ₂ is selected for a first encoding symbol 225, two intermediate symbols 215 may be randomly selected and combined into the first encoding symbol 225. Similarly, if the degree d ₁ is selected for a second encoding symbol, a single intermediate symbol 215 may be combined into the second encoding symbol 225. In some examples, the intermediate symbols 215 may be combined into encoding symbols 225 using a logic operation such as a logic XOR operation. In some examples, each encoding symbol 225 may include information identifying the source symbols 205 used to construct the encoding symbol 225. For example, the encoding symbol may include indices (e.g., s ₁, s ₂, s ₃, s _K, etc. ) associated with the source symbols 205 used to construct the encoding symbol 225.

The encoding symbols 225 may be transmitted as a set of encoded packets from the input node to the output node via one or more nodes (e.g., intermediate nodes) of the multi-hop network. In some examples, the encoding scheme 200 may be represented by a generator matrix G. The source symbols 205 contained in encoding symbols 225 of a given encoded packet may be represented by p _j, which may be defined by:

In some examples, one or more encoded packets may be lost based on the transmission environment. The output node may receive a subset of encoded packets (e.g., a quantity N of encoded packets) via the multi-hop network. The source symbols 205 contained in encoding symbols 225 of a given encoded packet received by the output node may be represented by d _k, which may be defined by:

Based on the encoding scheme 200, the output node may recover all source symbols 205 in the set of source symbols 205 when the matrix G _nk of the received packets is invertible. Additionally or alternatively, the output node may recover all source symbols 205 in the set of source symbols 205 when the matrix G _nk of the received packets has a rank K, where K is the quantity of source symbols 205 in the set of source symbols 205. To increase a probability of the output node successfully the set of source symbols 205, the encoding scheme 200 may be designed such that the representative generator matrix G _nk is invertible for a minimum quantity N of received encoded packets.

The output node may decode the received encoding symbols 225 to obtain the source symbols 205. The output node may begin a decoding process by identifying an encoding symbol 225 with an index t _j that is connected to a single source symbol 205 with an index s _i. The output node may determine the encoding symbol 225 with index t _j is equivalent to the source symbol 205 with index s _i. The output node may then apply an XOR operation to each other encoding symbol 225 connected to the source symbol 205 with index s _i, and remove all edges connected to the source symbol 205 with index s _i. The output node may repeat this process until each source symbol 205 is determined from the received encoding symbols 225.

In some examples, the decoding process may fail if there is no encoding symbol 225 connected to a single source symbol 205. Accordingly, the degree distribution Ω of the encoding symbols 225 received at the output node may have a direct impact on the probability of successfully decoding source symbols 205 transmitted in encoding symbols 225. For example, in a first degree distribution (which may in some examples be referred to as an ideal soliton distribution) , the probability ρ (i) of selecting a degree d _i (where d _i is an integer from 1 to K) may be defined by:

and

The first degree distribution may have a mode (e.g., a high probability) at d _i=2.

Alternatively, in a second degree distribution (which in some examples may be referred to as a robust soliton distribution) , the probability of selecting the degree d _i may be represented by μ (i) rather than ρ (i) of the ideal soliton distribution. The probability μ (i) may be defined by:

where τ (i) is a parameter defined in terms of constants c, δ, and

The parameter τ (i) may be defined for various values of i as:

The robust soliton distribution may have a greater probability that a random d _i=1 than the ideal soliton distribution, which may reduce the probability of the decoding process failing by increasing the probability that an encoding symbol 225 is connected to a single source symbol 205.

The encoding scheme 200 described herein may enable nodes of a multi-hop network to improve efficiency and reliability of communications in the multi-hop network by increasing the probability of successfully decoding source symbols 205 transmitted in encoding symbols 225.

FIG. 3 illustrates an example of a multi-hop network 300 that supports techniques for determining a degree distribution in accordance with aspects of the present disclosure. In some examples, the multi-hop network 300 may implement aspects of wireless communication system 100. For example, the multi-hop network 300 may include nodes 305, which may be examples of an IAB network node such as an IAB relay node, a UE 115, or a base station 105 as described herein.

A node 305-a, which may be referred to as an input node 305-a, may encode and transmit packets intended for a node 305-n, which may be referred to as an output node 305-n. The packets may be relayed through other nodes 305 (e.g., nodes 305-b through 305-m) , which may be referred to as relay nodes or intermediate nodes 305. The intermediate nodes 305 may be organized in stages 320. Each node 305 in a stage 320 may forward packets to a node 305 in a subsequent stage 320 via a link 315. A hop 310 may include the links 315 between nodes 305 of a first stage 320 and nodes 305 of a second stage 320.

The nodes 305 in a stage 320 may be located a same quantity of hops 310 from the input node 305-a. For example, a first stage 320-a (e.g., including nodes 305-b through 305-d) may be referred to as stage 1, where the nodes 305 in the first stage 320-a may be one hop (e.g., a hop 310-a) from the input node 305-a. Similarly, nodes 305 in a stage k (e.g., the stage 320-c) may be k hops from the input node 305-a (e.g., including the hop 310-a, the hop 310-b, and additional hops 310 (not shown) ) .

The multi-hop network 300 may include a quantity of hops 310 between the input node 305-a and the output node 305-n. The multi-hop network may also include a quantity of stages 320, where the quantity of stages 320 may be based on the quantity of hops 310. Each link 315 between nodes 305 may have an associated capacity C and erasure probability p.

The input node 305-a may encode packets using a fountain code, such as an LT code or a Raptor code. In some examples, the input node 305-a may encode packets according to the encoding scheme 200 as described with reference to FIG. 2. The input node 305-a may determine a first hop degree distribution for encoding packets based on a desired last hop degree distribution at the output node 305-n. In some examples, the desired last hop degree distribution may be an ideal soliton distribution or a robust soliton distribution, which may increase a probability of successfully decoding packets at the output node 305-n.

Encoding the packets may be based on the determined first hop degree distribution. In some examples, the input node 305-a may further determine the first hop degree distribution in an offline scenario based on parameters of the multi-hop network 300, including the quantity of hops 310, the quantity of stages 320, a respective quantity of nodes 305 in each stage 320, a respective capacity C of each link 315, a respective erasure probability p of each link 315, etc. In some examples, the input node 305-a may assume the capacity C and the erasure probability p of each link 315 is the same, which may reduce a complexity for determining the first hop degree distribution.

In some examples, the input node 305-a may determine the first hop degree distribution in an online scenario, which may be referred to as deep reinforcement learning. In an online scenario, the input node 305-a may transmit an indication of the desired last hop degree distribution to another device (not shown) in the multi-hop network 300. The input node 305-a may then receive an indication of the first hop degree distribution the input node 305-a is to use to improve a probability that the last hop degree distribution is close to the desired last hop degree distribution (e.g., the ideal soliton distribution or the robust soliton distribution) .

The techniques described herein may enable nodes 305 of the multi-hop network 300 to improve efficiency and reliability of communications in the multi-hop network 300 by increasing the probability of successfully decoding transmitted information.

FIG. 4 illustrates an example of a multi-hop network 400 that supports techniques for determining a degree distribution in accordance with aspects of the present disclosure. In some examples, the multi-hop network 400 may implement aspects of the wireless communication system 100 and the multi-hop network 300. For example, the multi-hop network 400 may include nodes 405, which may be examples of an IAB network node such as an IAB relay node, a UE 115, a base station 105, and/or a node 305 as described herein.

A node 405-a, which may be referred to as an input node 405-a, may encode and transmit packets intended for a node 405-c, which may be referred to as an output node 405-c. The packets may be relayed through other nodes 405 (e.g., a node 405-b) , which may be referred to as relay nodes or intermediate nodes 405. The intermediate nodes 405 may be organized in stages. Each node 405 in a stage may forward packets to a node 405 in a subsequent stage via a link 415. A hop may include the links 415 between stages.

The input node 405-a may encode packets using a fountain code, such as an LT code or a Raptor code. In some examples, the input node 405-a may encode packets according to the encoding scheme 200 as described with reference to FIG. 2. The input node 405-a may determine a first hop degree distribution Ω for encoding packets based on a desired last hop degree distribution Ω ^r at the output node 405-c. In some examples, the desired last hop degree distribution Ω ^r may be an ideal soliton distribution or a robust soliton distribution, which may increase a probability of successfully decoding packets at the output node 405-c.

As packets from the input node 405-a travel through the multi-hop network 400, a degree distribution at a given node 405 may change based on the transmission environment, the packets received, and the nodes from which the given node received the packets. For example, a first hop degree distribution Ω may initially be defined by a generating polynomial

That is, a node 405 of a first stage (i.e., a Stage 1 following the first hop in the multi-hop network 400, which may be referred to as Hop 1) may have a degree distribution Ω ¹ (x) =Ω (x) . The nodes 405 in Stage 1 may receive packets from the input node 405-a via links 415 including a link 415-a. The link 415-a may have a capacity C ₁ and an erasure probability p ₁. In some examples, each link 415 in the Hop 1 may have the same capacity C ₁ and the same erasure probability p ₁, and so packets at each node 405 in the Stage 1 may be associated with the same degree distribution Ω ¹ (x) .

In some examples, packets may be combined at nodes 405 to compensate for packet losses as they travel through the multi-hop network 400. For example, the degree distribution at a Stage k (e.g., a stage including a node 405-b) may be:

where

is a combination parameter defined in terms of the degree distribution Ω ^k-1 of the previous stage (i.e., a Stage k-1) :

Accordingly, the probability ρ (i) of selecting a degree d _i for a node 405 of the Stage k (e.g., the node 405-b) may be represented by

which may be defined as:

The node 405-b in the Stage k may receive packets from nodes 405 of the Stage k-1 via links 415 of a Hop k, including a link 415-b. The link 415-b may have a capacity C _k, i, j and an erasure probability p _k, i, j. In some examples, each link 415 in the Hop k may have the same capacity C _k and the same erasure probability p _k, and so packets at each node 405 in the Stage k may be associated with the same degree distribution Ω ^k (x) .

According to the techniques described herein, the input node 405-a may determine the first hop degree distribution Ω ¹ (x) based on the desired last hop degree distribution Ω ^r at the output node 405-c. In some examples, the input node 405-a may use an iterative scheme to derive a degree distribution of a previous stage based on a degree distribution of a current stage using the relations between degree distributions of consecutive stages. In some examples, the iterative scheme may be constrained such that the desired last hop degree distribution Ω ^r may be different from the first hop degree distribution Ω. Additionally or alternatively, the first hop degree distribution may be constrained such that, for nodes 405 of the Stage 1, Ω ₁<Ω ₂, while Ω _i>Ω _i+1 for i ≥2.

Given the desired degree distribution Ω ^r following the Hop H, the degree distribution of the previous stage (e.g., Ω ^H-1 of the Stage H-1) may be derived by determining:

such that

and

Using the iterative scheme described herein, the input node 405-a may in turn derive Ω ^H-2, Ω ^H-3, etc., until the first hop degree distribution Ω ¹ is obtained.

In some examples, the iterative scheme may include transforming the derivation described herein into a geometric programming (GP) problem, which may enable the input node 405-a to use one or more software packages to efficiently determine the first hop degree distribution Ω ¹. For example, based on the fact that

and given the desired degree distribution Ω ^r, the degree distribution Ω ^H-1 of the Stage H-1 may be derived by determining:

such that

and

Using the one or more software packages, the input node 405-a may then derive Ω ^H-2, Ω ^H-3, etc., in turn until the first hop degree distribution Ω ¹ is obtained.

The input node 405-a may use the iterative scheme described herein in an offline scenario. In some examples, the input node 405-a may further determine the first hop degree distribution Ω ¹ (as well as one or more intermediate degree distributions Ω ^k) based on parameters of the multi-hop network 400, including the quantity of hops, the quantity of stages, a respective quantity of nodes 405 in each stage, a respective capacity C of each link 415, a respective erasure probability p of each link 415, etc. In some examples, the input node 405-a may assume the capacity C and the erasure probability p are the same for each link 415 in the multi-hop network 400, which may reduce a complexity for determining the first hop degree distribution Ω ¹.

In some examples, the input node 405-a may determine the first hop degree distribution in an online scenario, which may be referred to as deep reinforcement learning. In an online scenario, the input node 405-a may transmit an indication of the desired last hop degree distribution Ω ^r to another device (not shown) in the multi-hop network 400. The input node 405-a may then receive an indication of the first hop degree distribution Ω ¹, which the input node 405-a may use to improve a probability that the last hop degree distribution is close to the desired last hop degree distribution Ω ^r (e.g., the ideal soliton distribution or the robust soliton distribution) .

The techniques described herein may enable nodes 405 of the multi-hop network 400 to improve efficiency and reliability of communications in the multi-hop network 400 by increasing the probability of successfully decoding transmitted information.

FIG. 5 shows a block diagram 500 of a device 505 that supports techniques for determining a degree distribution in a multi-hop network in accordance with aspects of the present disclosure. The device 505 may be an example of aspects of an IAB node such as an IAB relay node, a UE 115, or a base station 105 as described herein. The device 505 may include a receiver 510, a communications manager 515, and a transmitter 520. The device 505 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses) .

Receiver 510 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to techniques for determining a degree distribution in a multi-hop network, etc. ) . Information may be passed on to other components of the device 505. The receiver 510 may be an example of aspects of the

transceiver

820 or 920 as described with reference to FIGs. 8 and 9. The receiver 510 may utilize a single antenna or a set of antennas.

The communications manager 515 may identify a last hop fountain code degree distribution for an output node of the multi-hop network, where the last hop fountain code degree distribution is identified based on a target decoding success probability at the output node, determine a first hop fountain code degree distribution at the input node based on the last hop fountain code degree distribution and a quantity of hops in the multi-hop network, encode a set of packets at the input node according to a fountain code and based on determining the first hop fountain code degree distribution, and transmit the set of packets to one or more nodes of the multi-hop network via a first hop in the multi-hop network.

The communications manager 515 as described herein may be implemented to realize one or more potential advantages. One implementation may allow the device 505 to save power by communicating with other IAB nodes in a multi-hop network more efficiently. For example, the device 505 may efficiently communicate with IAB nodes by transmitting packets encoded according to the determined first hop fountain code degree distribution. Additionally, the device 505 may efficiently determine the first hop fountain code degree distribution such that the degree distribution at an output node is close to the ideal soliton distribution or the robust soliton distribution, which may increase a probability of another IAB node successfully decoding packets transmitted by the device 505. The communications manager 515 may be an example of aspects of the

communications manager

810 or 910 as described herein.

The communications manager 515, or its sub-components, may be implemented in hardware, software (e.g., executed by a processor) , or any combination thereof. If implemented in code executed by a processor, the functions of the communications manager 515, or its sub-components may be executed by a general-purpose processor, a digital signal processor (DSP) , an application-specific integrated circuit (ASIC) , a field-programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described in the present disclosure.

The communications manager 515, or its sub-components, may be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations by one or more physical components. In some examples, the communications manager 515, or its sub-components, may be a separate and distinct component in accordance with various aspects of the present disclosure. In some examples, the communications manager 515, or its sub-components, may be combined with one or more other hardware components, including but not limited to an input/output (I/O) component, a transceiver, a network server, another computing device, one or more other components described in the present disclosure, or a combination thereof in accordance with various aspects of the present disclosure.

Transmitter 520 may transmit signals generated by other components of the device 505. In some examples, the transmitter 520 may be collocated with a receiver 510 in a transceiver module. For example, the transmitter 520 may be an example of aspects of the

transceiver

820 or 920 as described with reference to FIGs. 8 and 9. The transmitter 520 may utilize a single antenna or a set of antennas.

FIG. 6 shows a block diagram 600 of a device 605 that supports techniques for determining a degree distribution in a multi-hop network in accordance with aspects of the present disclosure. The device 605 may be an example of aspects of a device 505 or an IAB node, such as an IAB relay node, a UE 115, or a base station 105 as described herein. The device 605 may include a receiver 610, a communications manager 615, and a transmitter 640. The device 605 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses) .

Receiver 610 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to techniques for determining a degree distribution in a multi-hop network, etc. ) . Information may be passed on to other components of the device 605. The receiver 610 may be an example of aspects of the

transceiver

820 or 920 as described with reference to FIGs. 8 and 9. The receiver 610 may utilize a single antenna or a set of antennas.

The communications manager 615 may be an example of aspects of the communications manager 515 as described herein. The communications manager 615 may include a last hop degree distribution manager 620, a first hop degree distribution manager 625, an encoder 630, and a packet transmission manager 635. The communications manager 615 may be an example of aspects of the

communications manager

810 or 910 as described herein.

The last hop degree distribution manager 620 may identify a last hop fountain code degree distribution for an output node of the multi-hop network, where the last hop fountain code degree distribution is identified based on a target decoding success probability at the output node.

The first hop degree distribution manager 625 may determine a first hop fountain code degree distribution at the input node based on the last hop fountain code degree distribution and a quantity of hops in the multi-hop network.

The encoder 630 may encode a set of packets at the input node according to a fountain code and based on determining the first hop fountain code degree distribution.

The packet transmission manager 635 may transmit the set of packets to one or more nodes of the multi-hop network via a first hop in the multi-hop network.

Transmitter 640 may transmit signals generated by other components of the device 605. In some examples, the transmitter 640 may be collocated with a receiver 610 in a transceiver module. For example, the transmitter 640 may be an example of aspects of the

transceiver

820 or 920 as described with reference to FIGs. 8 and 9. The transmitter 640 may utilize a single antenna or a set of antennas.

FIG. 7 shows a block diagram 700 of a communications manager 705 that supports techniques for determining a degree distribution in a multi-hop network in accordance with aspects of the present disclosure. The communications manager 705 may be an example of aspects of a communications manager 515, a communications manager 615, or a communications manager 810 described herein. The communications manager 705 may include a last hop degree distribution manager 710, a first hop degree distribution manager 715, an encoder 720, a packet transmission manager 725, a multi-hop network manager 730, a network link manager 735, and an online determination manager 740. Each of these modules may communicate, directly or indirectly, with one another (e.g., via one or more buses) .

The last hop degree distribution manager 710 may identify a last hop fountain code degree distribution for an output node of the multi-hop network, where the last hop fountain code degree distribution is identified based on a target decoding success probability at the output node. In some cases, the last hop fountain code degree distribution includes an ideal soliton distribution, a robust soliton distribution, or a combination thereof.

The first hop degree distribution manager 715 may determine a first hop fountain code degree distribution at the input node based on the last hop fountain code degree distribution and a quantity of hops in the multi-hop network. In some cases, the first hop fountain code degree distribution has a first length. In some cases, the last hop fountain code degree distribution has a second length that is less than or equal to the first length. In some cases, the first hop fountain code degree distribution is different from the last hop fountain code degree distribution.

The encoder 720 may encode a set of packets at the input node according to a fountain code and based on determining the first hop fountain code degree distribution. In some cases, the fountain code includes a Luby transform (LT) code, a rapid tornado (Raptor) code, or both.

The packet transmission manager 725 may transmit the set of packets to one or more nodes of the multi-hop network via a first hop in the multi-hop network.

The multi-hop network manager 730 may determine a quantity of stages in the multi-hop network based on the quantity of hops in the multi-hop network, where a first stage includes the one or more nodes, and where the first hop includes one or more links between the input node and the one or more nodes of the first stage. In some examples, the multi-hop network manager 730 may determine a respective quantity of nodes of each stage in the multi-hop network, where determining the first hop fountain code degree distribution at the input node is further based on the quantity of stages and the respective quantity of nodes of each stage in the multi-hop network.

In some examples, the multi-hop network manager 730 may determine an intermediate hop fountain code degree distribution for a node of a stage in the multi-hop network, where determining the first hop fountain code degree distribution at the input node is further based on determining the intermediate hop fountain code degree distribution. In some cases, the input node or the output node includes an integrated access and backhaul relay node.

The network link manager 735 may determine a respective erasure probability of each link in the multi-hop network. In some examples, the network link manager 735 may determine a respective capacity of each link in the multi-hop network, where determining the first hop fountain code degree distribution at the input node is further based on the respective erasure probability and the respective capacity of each link in the multi-hop network. In some cases, the respective erasure probability is the same for each link in the multi-hop network. In some cases, the respective capacity is the same for each link in the multi-hop network.

The online determination manager 740 may transmit an indication of the last hop fountain code degree distribution to a network device. In some examples, the online determination manager 740 may receive an indication of the first hop fountain code degree distribution based on the transmitting.

FIG. 8 shows a diagram of a system 800 including a device 805 that supports techniques for determining a degree distribution in a multi-hop network in accordance with aspects of the present disclosure. The device 805 may be an example of or include the components of device 505, device 605, or an IAB node such as a UE 115 as described herein. The device 805 may include components for bi-directional voice and data communications including components for transmitting and receiving communications, including a communications manager 810, a transceiver 820, an antenna 825, memory 830, a processor 840, and an I/O controller 850. These components may be in electronic communication via one or more buses (e.g., bus 855) .

The communications manager 810 may identify a last hop fountain code degree distribution for an output node of the multi-hop network, where the last hop fountain code degree distribution is identified based on a target decoding success probability at the output node, determine a first hop fountain code degree distribution at the input node based on the last hop fountain code degree distribution and a quantity of hops in the multi-hop network, encode a set of packets at the input node according to a fountain code and based on determining the first hop fountain code degree distribution, and transmit the set of packets to one or more nodes of the multi-hop network via a first hop in the multi-hop network.

Transceiver 820 may communicate bi-directionally, via one or more antennas, wired, or wireless links as described above. For example, the transceiver 820 may represent a wireless transceiver and may communicate bi-directionally with another wireless transceiver. The transceiver 820 may also include a modem to modulate the packets and provide the modulated packets to the antennas for transmission, and to demodulate packets received from the antennas.

In some cases, the wireless device may include a single antenna 825. However, in some cases the device may have more than one antenna 825, which may be capable of concurrently transmitting or receiving multiple wireless transmissions.

The memory 830 may include random-access memory (RAM) , read-only memory (ROM) , or a combination thereof. The memory 830 may store computer-readable code 835 including instructions that, when executed by a processor (e.g., the processor 840) cause the device to perform various functions described herein. In some cases, the memory 830 may contain, among other things, a basic input/output system (BIOS) which may control basic hardware or software operation such as the interaction with peripheral components or devices.

The processor 840 may include an intelligent hardware device (e.g., a general-purpose processor, a DSP, a central processing unit (CPU) , a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof) . In some cases, the processor 840 may be configured to operate a memory array using a memory controller. In other cases, a memory controller may be integrated into the processor 840. The processor 840 may be configured to execute computer-readable instructions stored in a memory (e.g., the memory 830) to cause the device 805 to perform various functions (e.g., functions or tasks supporting techniques for determining a degree distribution in a multi-hop network) .

The processor 840 of the device 805 (e.g., controlling the receiver 510, the transmitter 520, or the transceiver 820) may enable reliable transmission of encoded packets to the output node via the multi-hop network based on determining the first hop fountain code degree distribution. In some examples, the processor 840 of the device 805 may reconfigure parameters associated with encoding packets according to the fountain code. For example, the processor 840 of the device 805 may turn on one or more processing units for performing the encoding, increase a processing clock, or a similar mechanism within the device 805. As such, when additional information is scheduled to be encoded and transmitted, the processor 840 may be ready to respond more efficiently through the reduction of a ramp up in processing power. The improvements in power saving and communication efficiency may further reduce power consumption at the device 805 (for example, by reducing or eliminating unnecessary or failed transmissions, etc. ) .

The I/O controller 850 may manage input and output signals for the device 805. The I/O controller 850 may also manage peripherals not integrated into the device 805. In some cases, the I/O controller 850 may represent a physical connection or port to an external peripheral. In some cases, the I/O controller 850 may utilize an operating system such as

or another known operating system. In other cases, the I/O controller 850 may represent or interact with a modem, a keyboard, a mouse, a touchscreen, or a similar device. In some cases, the I/O controller 850 may be implemented as part of a processor. In some cases, a user may interact with the device 805 via the I/O controller 850 or via hardware components controlled by the I/O controller 850.

The code 835 may include instructions to implement aspects of the present disclosure, including instructions to support wireless communications. The code 835 may be stored in a non-transitory computer-readable medium such as system memory or other type of memory. In some cases, the code 835 may not be directly executable by the processor 840 but may cause a computer (e.g., when compiled and executed) to perform functions described herein.

FIG. 9 shows a diagram of a system 900 including a device 905 that supports techniques for determining a degree distribution in a multi-hop network in accordance with aspects of the present disclosure. The device 905 may be an example of or include the components of device 505, device 605, or an IAB node such as a relay node or a base station 105 as described herein. The device 905 may include components for bi-directional voice and data communications including components for transmitting and receiving communications, including a communications manager 910, a network communications manager 915, a transceiver 920, an antenna 925, memory 930, a processor 940, and an inter-station communications manager 945. These components may be in electronic communication via one or more buses (e.g., bus 955) .

The communications manager 910 may identify a last hop fountain code degree distribution for an output node of the multi-hop network, where the last hop fountain code degree distribution is identified based on a target decoding success probability at the output node, determine a first hop fountain code degree distribution at the input node based on the last hop fountain code degree distribution and a quantity of hops in the multi-hop network, encode a set of packets at the input node according to a fountain code and based on determining the first hop fountain code degree distribution, and transmit the set of packets to one or more nodes of the multi-hop network via a first hop in the multi-hop network.

Network communications manager 915 may manage communications with the core network (e.g., via one or more wired backhaul links) . For example, the network communications manager 915 may manage the transfer of data communications for client devices, such as one or more UEs 115.

Transceiver 920 may communicate bi-directionally, via one or more antennas, wired, or wireless links as described above. For example, the transceiver 920 may represent a wireless transceiver and may communicate bi-directionally with another wireless transceiver. The transceiver 920 may also include a modem to modulate the packets and provide the modulated packets to the antennas for transmission, and to demodulate packets received from the antennas.

In some cases, the wireless device may include a single antenna 925. However, in some cases the device may have more than one antenna 925, which may be capable of concurrently transmitting or receiving multiple wireless transmissions.

The memory 930 may include RAM, ROM, or a combination thereof. The memory 930 may store computer-readable code 935 including instructions that, when executed by a processor (e.g., the processor 940) cause the device to perform various functions described herein. In some cases, the memory 930 may contain, among other things, a BIOS which may control basic hardware or software operation such as the interaction with peripheral components or devices.

The processor 940 may include an intelligent hardware device (e.g., a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof) . In some cases, the processor 940 may be configured to operate a memory array using a memory controller. In other cases, a memory controller may be integrated into the processor 940. The processor 940 may be configured to execute computer-readable instructions stored in a memory (e.g., the memory 930) to cause the device 905 to perform various functions (e.g., functions or tasks supporting techniques for determining a degree distribution in a multi-hop network) .

The processor 940 of the device 905 (e.g., controlling the receiver 510, the transmitter 520, or the transceiver 920) may enable reliable transmission of encoded packets to the output node via the multi-hop network based on determining the first hop fountain code degree distribution. In some examples, the processor 940 of the device 905 may reconfigure parameters associated with encoding packets according to the fountain code. For example, the processor 940 of the device 905 may turn on one or more processing units for performing the encoding, increase a processing clock, or a similar mechanism within the device 905. As such, when additional information is scheduled to be encoded and transmitted, the processor 940 may be ready to respond more efficiently through the reduction of a ramp up in processing power. The improvements in power saving and communication efficiency may further reduce power consumption at the device 905 (for example, by reducing or eliminating unnecessary or failed transmissions, etc. ) .

Inter-station communications manager 945 may manage communications with other base station 105, and may include a controller or scheduler for controlling communications with UEs 115 in cooperation with other base stations 105. For example, the inter-station communications manager 945 may coordinate scheduling for transmissions to UEs 115 for various interference mitigation techniques such as beamforming or joint transmission. In some examples, inter-station communications manager 945 may provide an X2 interface within an LTE/LTE-A wireless communication network technology to provide communication between base stations 105.

The code 935 may include instructions to implement aspects of the present disclosure, including instructions to support wireless communications. The code 935 may be stored in a non-transitory computer-readable medium such as system memory or other type of memory. In some cases, the code 935 may not be directly executable by the processor 940 but may cause a computer (e.g., when compiled and executed) to perform functions described herein.

FIG. 10 shows a flowchart illustrating a method 1000 that supports techniques for determining a degree distribution in a multi-hop network in accordance with aspects of the present disclosure. The operations of method 1000 may be implemented by a UE 115 or base station 105 or its components as described herein. For example, the operations of method 1000 may be performed by a communications manager as described with reference to FIGs. 5 through 9. In some examples, a UE or base station may execute a set of instructions to control the functional elements of the UE or base station to perform the functions described below. Additionally or alternatively, a UE or base station may perform aspects of the functions described below using special-purpose hardware.

At 1005, the UE or base station may identify a last hop fountain code degree distribution for an output node of the multi-hop network, where the last hop fountain code degree distribution is identified based on a target decoding success probability at the output node. The operations of 1005 may be performed according to the methods described herein. In some examples, aspects of the operations of 1005 may be performed by a last hop degree distribution manager as described with reference to FIGs. 5 through 9.

At 1010, the UE or base station may determine a first hop fountain code degree distribution at the input node based on the last hop fountain code degree distribution and a quantity of hops in the multi-hop network. The operations of 1010 may be performed according to the methods described herein. In some examples, aspects of the operations of 1010 may be performed by a first hop degree distribution manager as described with reference to FIGs. 5 through 9.

At 1015, the UE or base station may encode a set of packets at the input node according to a fountain code and based on determining the first hop fountain code degree distribution. The operations of 1015 may be performed according to the methods described herein. In some examples, aspects of the operations of 1015 may be performed by an encoder as described with reference to FIGs. 5 through 9.

At 1020, the UE or base station may transmit the set of packets to one or more nodes of the multi-hop network via a first hop in the multi-hop network. The operations of 1020 may be performed according to the methods described herein. In some examples, aspects of the operations of 1020 may be performed by a packet transmission manager as described with reference to FIGs. 5 through 9.

FIG. 11 shows a flowchart illustrating a method 1100 that supports techniques for determining a degree distribution in a multi-hop network in accordance with aspects of the present disclosure. The operations of method 1100 may be implemented by an IAB node, such as an IAB relay node, a UE 115, or base station 105 or its components as described herein. For example, the operations of method 1100 may be performed by a communications manager as described with reference to FIGs. 5 through 9. In some examples, a UE or base station may execute a set of instructions to control the functional elements of the UE or base station to perform the functions described below. Additionally or alternatively, a UE or base station may perform aspects of the functions described below using special-purpose hardware.

At 1105, the IAB node may identify a last hop fountain code degree distribution for an output node of the multi-hop network, where the last hop fountain code degree distribution is identified based on a target decoding success probability at the output node. The operations of 1105 may be performed according to the methods described herein. In some examples, aspects of the operations of 1105 may be performed by a last hop degree distribution manager as described with reference to FIGs. 5 through 9.

At 1110, the IAB node may determine a quantity of stages in the multi-hop network based on the quantity of hops in the multi-hop network, where a first stage includes the one or more nodes, and where the first hop includes one or more links between the input node and the one or more nodes of the first stage. The operations of 1110 may be performed according to the methods described herein. In some examples, aspects of the operations of 1110 may be performed by a multi-hop network manager as described with reference to FIGs. 5 through 9.

At 1115, the IAB node may determine a respective quantity of nodes of each stage in the multi-hop network. The operations of 1115 may be performed according to the methods described herein. In some examples, aspects of the operations of 1115 may be performed by a multi-hop network manager as described with reference to FIGs. 5 through 9.

At 1120, the IAB node may determine a respective erasure probability of each link in the multi-hop network. The operations of 1120 may be performed according to the methods described herein. In some examples, aspects of the operations of 1120 may be performed by a network link manager as described with reference to FIGs. 5 through 9.

At 1125, the IAB node may determine a respective capacity of each link in the multi-hop network. The operations of 1125 may be performed according to the methods described herein. In some examples, aspects of the operations of 1125 may be performed by a network link manager as described with reference to FIGs. 5 through 9.

At 1130, the IAB node may determine a first hop fountain code degree distribution at the input node based on the last hop fountain code degree distribution, the quantity of hops in the multi-hop network, the quantity of stages, the respective quantity of nodes of each stage in the multi-hop network, and the respective erasure probability and the respective capacity of each link in the multi-hop network. The operations of 1130 may be performed according to the methods described herein. In some examples, aspects of the operations of 1130 may be performed by a first hop degree distribution manager as described with reference to FIGs. 5 through 9.

At 1135, the IAB node may encode a set of packets at the input node according to a fountain code and based on determining the first hop fountain code degree distribution. The operations of 1135 may be performed according to the methods described herein. In some examples, aspects of the operations of 1135 may be performed by an encoder as described with reference to FIGs. 5 through 9.

At 1140, the IAB node may transmit the set of packets to one or more nodes of the multi-hop network via a first hop in the multi-hop network. The operations of 1140 may be performed according to the methods described herein. In some examples, aspects of the operations of 1140 may be performed by a packet transmission manager as described with reference to FIGs. 5 through 9.

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

Although aspects of an LTE, LTE-A, LTE-A Pro, or NR system may be described for purposes of example, and LTE, LTE-A, LTE-A Pro, or NR terminology may be used in much of the description, the techniques described herein are applicable beyond LTE, LTE-A, LTE-A Pro, or NR networks. For example, the described techniques may be applicable to various other wireless communications systems such as Ultra Mobile Broadband (UMB) , Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi) , IEEE 802.16 (WiMAX) , IEEE 802.20, Flash-OFDM, as well as other systems and radio technologies not explicitly mentioned herein.

Information and signals described herein may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

The various illustrative blocks and components described in connection with the disclosure herein may be implemented or performed with a general-purpose processor, a DSP, an ASIC, a CPU, 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 in the alternative, the processor may be any processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration) .

The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. If implemented in software executed by a processor, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Other examples and implementations are within the scope of the disclosure and appended claims. For example, due to the nature of software, functions described herein may be implemented using software executed by a processor, hardware, firmware, hardwiring, or combinations of any of these. Features implementing functions may also be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations.

Computer-readable media includes both non-transitory computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A non-transitory storage medium may be any available medium that may be accessed by a general-purpose or special purpose computer. By way of example, and not limitation, non-transitory computer-readable media may include RAM, ROM, electrically erasable programmable ROM (EEPROM) , flash memory, compact disk (CD) ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other non-transitory medium that may be used to carry or store desired program code means in the form of instructions or data structures and that may be accessed by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL) , or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of computer-readable medium. Disk and disc, as used herein, include CD, laser disc, optical disc, digital versatile disc (DVD) , floppy disk and Blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above are also included within the scope of computer-readable media.

As used herein, including in the claims, “or” as used in a list of items (e.g., a list of items prefaced by a phrase such as “at least one of” or “one or more of” ) indicates an inclusive 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 and B and C) . Also, as used herein, the phrase “based on” shall not be construed as a reference to a closed set of conditions. For example, an example step that is described as “based on condition A” may be based on both a condition A and a condition B without departing from the scope of the present disclosure. In other words, as used herein, the phrase “based on” shall be construed in the same manner as the phrase “based at least in part on. ” As used herein, the term “and/or, ” when used in a list of two or more items, means that any one of the listed items can be employed by itself, or any combination of two or more of the listed items can be employed. For example, if a composition is described as containing components A, B, and/or C, the composition can contain A alone; B alone; C alone; A and B in combination; A and C in combination; B and C in combination; or A, B, and C in combination.

In the appended figures, similar components or features may have the same reference label. Further, various components of the same type may be distinguished by following the reference label by a dash and a second label that distinguishes among the similar components. If just the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label irrespective of the second reference label, or other subsequent reference label.

The description set forth herein, in connection with the appended drawings, describes example configurations and does not represent all the examples that may be implemented or that are within the scope of the claims. The term “example” used herein means “serving as an example, instance, or illustration, ” and not “preferred” or “advantageous over other examples. ” The detailed description includes specific details for the purpose of providing an understanding of the described techniques. These techniques, however, may be practiced without these specific details. In some instances, known structures and devices are shown in block diagram form in order to avoid obscuring the concepts of the described examples.

The description herein is provided to enable a person having ordinary skill in the art to make or use the disclosure. Various modifications to the disclosure will be apparent to a person having ordinary skill in the art, and the generic principles defined herein may be applied to other variations without departing from the scope of the disclosure. Thus, the disclosure is not limited to the examples and designs described herein, but is to be accorded the broadest scope consistent with the principles and novel features disclosed herein.

Claims

A method for wireless communications at an input node of a multi-hop network, comprising:

identifying a last hop fountain code degree distribution for an output node of the multi-hop network, wherein the last hop fountain code degree distribution is identified based at least in part on a target decoding success probability at the output node;

determining a first hop fountain code degree distribution at the input node based at least in part on the last hop fountain code degree distribution and a quantity of hops in the multi-hop network;

encoding a plurality of packets at the input node according to a fountain code and based at least in part on determining the first hop fountain code degree distribution; and

transmitting the plurality of packets to one or more nodes of the multi-hop network via a first hop in the multi-hop network.
The method of claim 1, further comprising:

determining a quantity of stages in the multi-hop network based at least in part on the quantity of hops in the multi-hop network, wherein a first stage comprises the one or more nodes, and wherein the first hop comprises one or more links between the input node and the one or more nodes of the first stage; and

determining a respective quantity of nodes of each stage in the multi-hop network, wherein determining the first hop fountain code degree distribution at the input node is further based at least in part on the quantity of stages and the respective quantity of nodes of each stage in the multi-hop network.
The method of claim 2, further comprising:

determining an intermediate hop fountain code degree distribution for a node of a stage in the multi-hop network, wherein determining the first hop fountain code degree distribution at the input node is further based at least in part on determining the intermediate hop fountain code degree distribution.
The method of claim 2, further comprising:

determining a respective erasure probability of each link in the multi-hop network; and

determining a respective capacity of each link in the multi-hop network, wherein determining the first hop fountain code degree distribution at the input node is further based at least in part on the respective erasure probability and the respective capacity of each link in the multi-hop network.
The method of claim 4, wherein:

the respective erasure probability is the same for each link in the multi-hop network; and

the respective capacity is the same for each link in the multi-hop network.
The method of claim 1, wherein determining the first hop fountain code degree distribution comprises:

transmitting an indication of the last hop fountain code degree distribution to a network device; and

receiving an indication of the first hop fountain code degree distribution based at least in part on the transmitting.
The method of claim 1, wherein:

the first hop fountain code degree distribution has a first length; and

the last hop fountain code degree distribution has a second length that is less than or equal to the first length.
The method of claim 1, wherein the first hop fountain code degree distribution is different from the last hop fountain code degree distribution.
The method of claim 1, wherein the input node or the output node comprises an integrated access and backhaul relay node.
The method of claim 1, wherein the last hop fountain code degree distribution comprises an ideal soliton distribution, a robust soliton distribution, or a combination thereof.
The method of claim 1, wherein the fountain code comprises a Luby transform (LT) code, a rapid tornado (Raptor) code, or both.
An apparatus for wireless communications at an input node of a multi-hop network, comprising:

a processor,

memory coupled with the processor; and

instructions stored in the memory and executable by the processor to cause the apparatus to:

identify a last hop fountain code degree distribution for an output node of the multi-hop network, wherein the last hop fountain code degree distribution is identified based at least in part on a target decoding success probability at the output node;

determine a first hop fountain code degree distribution at the input node based at least in part on the last hop fountain code degree distribution and a quantity of hops in the multi-hop network;

encode a plurality of packets at the input node according to a fountain code and based at least in part on determining the first hop fountain code degree distribution; and

transmit the plurality of packets to one or more nodes of the multi-hop network via a first hop in the multi-hop network.
The apparatus of claim 12, wherein the instructions are further executable by the processor to cause the apparatus to:

determine a quantity of stages in the multi-hop network based at least in part on the quantity of hops in the multi-hop network, wherein a first stage comprises the one or more nodes, and wherein the first hop comprises one or more links between the input node and the one or more nodes of the first stage; and

determine a respective quantity of nodes of each stage in the multi-hop network, wherein determining the first hop fountain code degree distribution at the input node is further based at least in part on the quantity of stages and the respective quantity of nodes of each stage in the multi-hop network.
The apparatus of claim 13, wherein the instructions are further executable by the processor to cause the apparatus to:

determine an intermediate hop fountain code degree distribution for a node of a stage in the multi-hop network, wherein determining the first hop fountain code degree distribution at the input node is further based at least in part on determining the intermediate hop fountain code degree distribution.
The apparatus of claim 13, wherein the instructions are further executable by the processor to cause the apparatus to:

determine a respective erasure probability of each link in the multi-hop network; and

determine a respective capacity of each link in the multi-hop network, wherein determining the first hop fountain code degree distribution at the input node is further based at least in part on the respective erasure probability and the respective capacity of each link in the multi-hop network.
The apparatus of claim 15, wherein:

the respective erasure probability is the same for each link in the multi-hop network; and

the respective capacity is the same for each link in the multi-hop network.
The apparatus of claim 12, wherein the instructions are further executable by the processor to cause the apparatus to:

transmit an indication of the last hop fountain code degree distribution to a network device; and

receive an indication of the first hop fountain code degree distribution based at least in part on the transmitting.
The apparatus of claim 12, wherein:

the first hop fountain code degree distribution has a first length; and

the last hop fountain code degree distribution has a second length that is less than or equal to the first length.
The apparatus of claim 12, wherein the first hop fountain code degree distribution is different from the last hop fountain code degree distribution.
The apparatus of claim 12, wherein the input node or the output node comprises an integrated access and backhaul relay node.
The apparatus of claim 12, wherein the last hop fountain code degree distribution comprises an ideal soliton distribution, a robust soliton distribution, or a combination thereof.
The apparatus of claim 12, wherein the fountain code comprises a Luby transform (LT) code, a rapid tornado (Raptor) code, or both.
An apparatus for wireless communications at an input node of a multi-hop network, comprising:

means for identifying a last hop fountain code degree distribution for an output node of the multi-hop network, wherein the last hop fountain code degree distribution is identified based at least in part on a target decoding success probability at the output node;

means for determining a first hop fountain code degree distribution at the input node based at least in part on the last hop fountain code degree distribution and a quantity of hops in the multi-hop network;

means for encoding a plurality of packets at the input node according to a fountain code and based at least in part on determining the first hop fountain code degree distribution; and

means for transmitting the plurality of packets to one or more nodes of the multi-hop network via a first hop in the multi-hop network.
The apparatus of claim 23, further comprising:

means for determining a quantity of stages in the multi-hop network based at least in part on the quantity of hops in the multi-hop network, wherein a first stage comprises the one or more nodes, and wherein the first hop comprises one or more links between the input node and the one or more nodes of the first stage; and

means for determining a respective quantity of nodes of each stage in the multi-hop network, wherein determining the first hop fountain code degree distribution at the input node is further based at least in part on the quantity of stages and the respective quantity of nodes of each stage in the multi-hop network.
The apparatus of claim 24, further comprising:

means for determining an intermediate hop fountain code degree distribution for a node of a stage in the multi-hop network, wherein determining the first hop fountain code degree distribution at the input node is further based at least in part on determining the intermediate hop fountain code degree distribution.
The apparatus of claim 24, further comprising:

means for determining a respective erasure probability of each link in the multi-hop network; and

means for determining a respective capacity of each link in the multi-hop network, wherein determining the first hop fountain code degree distribution at the input node is further based at least in part on the respective erasure probability and the respective capacity of each link in the multi-hop network.
The apparatus of claim 26, wherein:

the respective erasure probability is the same for each link in the multi-hop network; and

the respective capacity is the same for each link in the multi-hop network.
The apparatus of claim 23, further comprising:

means for transmitting an indication of the last hop fountain code degree distribution to a network device; and

means for receiving an indication of the first hop fountain code degree distribution based at least in part on the transmitting.
The apparatus of claim 23, wherein:

the first hop fountain code degree distribution has a first length; and

the last hop fountain code degree distribution has a second length that is less than or equal to the first length.
The apparatus of claim 23, wherein the first hop fountain code degree distribution is different from the last hop fountain code degree distribution.
The apparatus of claim 23, wherein the input node or the output node comprises an integrated access and backhaul relay node.
The apparatus of claim 23, wherein the last hop fountain code degree distribution comprises an ideal soliton distribution, a robust soliton distribution, or a combination thereof.
The apparatus of claim 23, wherein the fountain code comprises a Luby transform (LT) code, a rapid tornado (Raptor) code, or both.
A non-transitory computer-readable medium storing code for wireless communications at an input node of a multi-hop network, the code comprising instructions executable by a processor to:

identify a last hop fountain code degree distribution for an output node of the multi-hop network, wherein the last hop fountain code degree distribution is identified based at least in part on a target decoding success probability at the output node;

determine a first hop fountain code degree distribution at the input node based at least in part on the last hop fountain code degree distribution and a quantity of hops in the multi-hop network;

encode a plurality of packets at the input node according to a fountain code and based at least in part on determining the first hop fountain code degree distribution; and

transmit the plurality of packets to one or more nodes of the multi-hop network via a first hop in the multi-hop network.
The non-transitory computer-readable medium of claim 34, wherein the instructions are further executable to:

determine a quantity of stages in the multi-hop network based at least in part on the quantity of hops in the multi-hop network, wherein a first stage comprises the one or more nodes, and wherein the first hop comprises one or more links between the input node and the one or more nodes of the first stage; and

determine a respective quantity of nodes of each stage in the multi-hop network, wherein determining the first hop fountain code degree distribution at the input node is further based at least in part on the quantity of stages and the respective quantity of nodes of each stage in the multi-hop network.
The non-transitory computer-readable medium of claim 35, wherein the instructions are further executable to:

determine an intermediate hop fountain code degree distribution for a node of a stage in the multi-hop network, wherein determining the first hop fountain code degree distribution at the input node is further based at least in part on determining the intermediate hop fountain code degree distribution.
The non-transitory computer-readable medium of claim 35, wherein the instructions are further executable to:

determine a respective erasure probability of each link in the multi-hop network; and

determine a respective capacity of each link in the multi-hop network, wherein determining the first hop fountain code degree distribution at the input node is further based at least in part on the respective erasure probability and the respective capacity of each link in the multi-hop network.
The non-transitory computer-readable medium of claim 37, wherein:

the respective erasure probability is the same for each link in the multi-hop network; and

the respective capacity is the same for each link in the multi-hop network.
The non-transitory computer-readable medium of claim 34, wherein the instructions are further executable to:

transmit an indication of the last hop fountain code degree distribution to a network device; and

receive an indication of the first hop fountain code degree distribution based at least in part on the transmitting.
The non-transitory computer-readable medium of claim 34, wherein:

the first hop fountain code degree distribution has a first length; and

the last hop fountain code degree distribution has a second length that is less than or equal to the first length.
The non-transitory computer-readable medium of claim 34, wherein the first hop fountain code degree distribution is different from the last hop fountain code degree distribution.
The non-transitory computer-readable medium of claim 34, wherein the input node or the output node comprises an integrated access and backhaul relay node.
The non-transitory computer-readable medium of claim 34, wherein the last hop fountain code degree distribution comprises an ideal soliton distribution, a robust soliton distribution, or a combination thereof.
The non-transitory computer-readable medium of claim 34, wherein the fountain code comprises a Luby transform (LT) code, a rapid tornado (Raptor) code, or both.