WO2024263319A1

WO2024263319A1 - Techniques for supporting multi-hop transmissions

Info

Publication number: WO2024263319A1
Application number: PCT/US2024/029754
Authority: WO
Inventors: Arnab ROY; Martin Kugler; Ayman F. Naguib; Onur Sahin; Ahmed Gamal Helmy MOHAMED
Original assignee: Apple Inc.
Priority date: 2023-06-23
Filing date: 2024-05-16
Publication date: 2024-12-26

Abstract

Embodiments provide resource-efficient techniques of dynamically adjusting collective channel resources across multiple hop transmissions that utilize UE-to-UE relays, such as based on current QoS requirements and utilizing statistical multiplexing. Various embodiments include a hybrid mechanism that utilizes components of centralized and UE autonomous scheduling for communications within a UE cluster (or UE group). In many embodiments, UEs may be allocated resources for a certain number of retransmissions for a multi-hop transmission within a UE cluster, but then surrender resources that are not needed. In several embodiments, the number of retransmission attempts per hop may be adjusted in the case of autonomous retransmissions to satisfy QoS requirements of the traffic. In several such embodiments, packet forwarding is supported at each hop when the packet is correctly received, even before the allowed number of retransmission attempts.

Description

TECHNIQUES FOR SUPPORTING MULTI-HOP TRANSMISSIONS

FIELD OF INVENTION

[0001] This disclosure related generally to wireless technology and more particularly to supporting multi -hop transmissions.

BACKGROUND

[0002] Generally, a mesh network is a local area network topology in which nodes (i.e., bridges, switches, and other network devices) connect directly, dynamically, and non-hierarchically to as many other nodes as possible and cooperate with one another to efficiently route data to and from clients. In a mesh network, a routed message is propagated along a path by hopping from node to node until it reaches its destination. Multi-hop routing may refer to a type of communication in radio networks in which network coverage area is larger than radio range of single nodes. Therefore, to reach some destination a node can use other nodes as relays. Some types of mesh network may utilize device-to- device communication. Device-to-Device (D2D) communication in cellular networks generally refers to direct communication between two mobile users without traversing the Base Station (BS) or core network.

[0003] The fifth-generation technology standard for broadband cellular networks (5G) supports some aspects of mesh networks and D2D communication. For example, the industry consortium that sets standards for 5G, the 3rd Generation Partnership Project (3GPP), has introduced standards for sidelink communications. In 5G, sidelink communications may refer to the use of device-to-device communication as a way to extend the network coverage outside the area directly covered by the network infrastructure. However, under the current standards, sidelink communications are limited to a single hop.

BRIEF SUMMARY

[0004] Processes, machines, and articles of manufacture for supporting multi-hop transmissions are described. It will be appreciated that the embodiments may be combined in any number of ways without departing from the scope of this disclosure.

[0005] Embodiments may include identifying transmission resources comprising a plurality of slots allocated for transmission of payload data in at least one hop of a multi-hop transmission from a source UE to a destination UE via one or more intermediate UEs, wherein the one or more intermediate UEs comprise at least one primary UE communicatively coupled with a base station (BS); determining the payload data is unavailable for transmission in a first slot of the plurality of slots; transmitting non-payload data in the first slot of the plurality of slots in response to the payload data being unavailable for transmission in the first slot; determining the payload data is available for transmission in a second slot of the plurality of slots; and transmitting the payload data in the second slot of the plurality of slots in response to the payload data being available for transmission in the second slot.

[0006] Embodiments may include receiving a resource request associated with a multi-hop transmission by a UE cluster, the UE cluster comprising a source UE, a destination UE, and one or more intermediate UEs, and the multi-hop transmission to send payload data from the source UE to the destination UE via the one or more intermediate UEs; determining a set of resources for the multi-hop transmission by the UE cluster, the set of resources including resources for initial transmissions and a maximum number of retransmissions on each hop of the multi-hop transmission; transmitting a resource response to the at least one primary UE comprising the set of resources determined for the multi-hop transmission; receiving an indication of a set of surrendered resources, the set of surrendered resources comprising a subset of the set of resources determined for the multi-hop transmission by the UE cluster; and reassigning at least a portion of the set of surrendered resources to a transmission separate from the multi-hop transmission.

[0007] Other processes, machines, and articles of manufacture are also described hereby, which may be combined in any number of ways, such as with the embodiments of the brief summary, without departing from the scope of this disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The present disclosure is illustrated by way of example and not limitation in the figures of the accompanying drawings in which like references indicate similar elements. To easily identify the discussion of any particular element or act, the most significant digit or digits in a reference number refer to the figure number in which that element is first introduced.

[0009] FIG. 1 illustrates an example wireless communication system according to some embodiments.

[0010] FIG. 2 illustrates a base station (BS) in communication with a user equipment (UE) device according to some embodiments.

[0011] FIG. 3 illustrates an example block diagram of a UE according to some embodiments.

[0012] FIG. 4 illustrates an example block diagram of a BS according to some embodiments.

[0013] FIG. 5 illustrates an example block diagram of cellular communication circuitry according to some embodiments.

[0014] FIG. 6 illustrates an example block diagram of a network message according to some embodiments.

[0015] FIGS. 7A and 7B illustrate exemplary operating environments for multi -hop transmissions according to some embodiments.

[0016] FIG. 8 illustrates an exemplary process diagram for multi-hop transmissions and local resource reconfiguration in an acknowledge mode according to some embodiments. [0017] FIG. 9 illustrates an exemplary process diagram for multi-hop transmissions and local resource reconfiguration in an autonomous retransmission mode according to some embodiments.

[0018] FIG. 10 illustrates an exemplary process diagram for adaptive radio link control (RLC) mode assignments in support of multi -hop transmissions according to some embodiments.

[0019] FIG. 11 illustrates an exemplary process diagram for dynamic parameter assignments in support of multi -hop transmissions according to some embodiments.

[0020] FIG. 12 illustrates a logic flow of an exemplary technique associated with multi -hop transmissions according to some embodiments.

[0021] FIG. 13 illustrates a logic flow of an exemplary technique associated with resource assignment according to some embodiments.

DETAILED DESCRIPTION

[0022] Generally, this disclosure describes techniques for supporting multi-hop transmissions with UE-to-UE relays. More specifically, embodiments are directed to supporting multi -hop transmissions between a source UE and a destination UE via one or more intermediate UEs. In the following description, numerous specific details are set forth to provide thorough explanation of embodiments of the present disclosure. It will be apparent, however, to one skilled in the art, that embodiments of the present disclosure may be practiced without these specific details. In other instances, well-known components, structures, and techniques have not been shown in detail in order not to obscure the understanding of this description.

[0023] Reference in the specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the disclosure. The appearances of the phrase “in one embodiment” in various places in the specification do not necessarily all refer to the same embodiment.

[0024] In the following description and claims, the terms “coupled” and “connected,” along with their derivatives, may be used. It should be understood that these terms are not intended as synonyms for each other. “Coupled” is used to indicate that two or more elements, which may or may not be in direct physical or electrical contact with each other, co-operate or interact with each other. “Connected” is used to indicate the establishment of communication between two or more elements that are coupled with each other.

[0025] The processes depicted in the figures that follow, are performed by processing logic that comprises hardware (e.g., circuitry, dedicated logic, etcetera), software (such as is run on a general- purpose computer system or a dedicated machine), or a combination of both. Although the processes are described below in terms of some sequential operations, it should be appreciated that some of the operations described may be performed in different order. Moreover, some operations may be performed in parallel rather than sequentially. [0026] The terms “server,” “client,” and “device” are intended to refer generally to data processing systems rather than specifically to a particular form factor for the server, client, and/or device.

[0027] Existing techniques for telecommunications that utilize UE-to-UE relays, such as sidelink communications, fail to support multi -hop transmissions. Further, extension of existing sidelink communication techniques cannot achieve low and deterministic latency for multi-hop transmissions, such as for ultra reliable and low latency communications (URLLC). For example, existing resource reservation mechanisms for UE-to-UE relays do not account for retransmissions during the initial resource allocations. For example, existing techniques may assign channel resources in a reactive manner such that channel resources for successive hops are assigned in a consecutive manner. In some such examples, the UE may look for resources after receiving the payload data from another UE. In another example, one existing way to support retransmissions on intermediate hops is to overprovision resources on each hop. However, this is inefficient since each hop may not need retransmissions. Further, if a current hop transmission requires retransmission, then the channel allocations for subsequent hops are wasted. Additionally, there is no existing technique to dynamically adjust transmission reliability for multi-hop transmissions based on Quality of Service (QoS) in a resource efficient manner. Such limitations can drastically reduce the usability and applicability of telecommunication systems, contributing to inefficient systems, devices, and techniques with limited capabilities.

[0028] Accordingly, many embodiments disclosed hereby provide resource-efficient techniques of dynamically adjusting collective channel resources across multiple hop transmissions that utilize UE- to-UE relays, such as based on current QoS requirements and utilizing statistical multiplexing. Various embodiments include a hybrid mechanism that utilizes components of centralized and UE autonomous scheduling for communications within a UE cluster (or UE group). In many embodiments, UEs may be allocated resources for a certain number of retransmissions for a multi-hop transmission within a UE cluster, but then surrender resources that are not needed. In several embodiments, the number of retransmission attempts per hop may be adjusted in the case of autonomous retransmissions to satisfy QoS requirements of the traffic. In several such embodiments, packet forwarding is supported at each hop when the packet is correctly received, even before the allowed number of retransmission attempts. [0029] In many embodiments, UEs may dynamically adjust the utilization of granted resources for multi-hop transmissions based on availability of data from preceding nodes and/or local channel conditions. For example, early resources may be filled with dummy/null data when the UE is not yet ready to transmit a data packet, such as due to transmission on the previous hop being incomplete. In another example, resources may be surrendered at the end of an allocation when an acknowledgement (e.g., ACK) is received for the data packet transmission. In yet another example, various parameters, such as RLC mode or number of transmission attempts, may be dynamically adjusted for different hops based on data packet characteristics and/or local channel conditions. [0030] In these and other ways, components/techniques described hereby may provide many technical advantages. For instance, the computer-based techniques of the current disclosure improve the functioning of a telecommunications system as compared to conventional approaches because the techniques enable robust support for multi-hop transmissions that can improve accessibility and coverage of telecommunication networks, reduce overhead, and provide expanded capabilities versus conventional approaches. Further, embodiments disclosed hereby can be practically utilized to improve the functioning of a computer and/or to improve a variety of technical fields including telecommunications, 5G networks, mesh networks, multi-hop transmissions, URLLC, D2D communications, and/or UE-to-UE relays.

[0031] It will be appreciated that various aspects of telecommunication networks, capabilities, protocols, formats, and procedures relevant to the techniques described and terms referenced herein can be found in 3GPP technical specifications (TS), such as TS 38.300 and TS 38.351.

[0032] FIG. 1 illustrates a simplified example wireless communication system, according to some embodiments. It is noted that the system of FIG. 1 is merely one example of a possible system, and that features of this disclosure may be implemented in any of various systems, as desired.

[0033] As shown, the example wireless communication system includes a base station 102A which communicates over a transmission medium with one or more user devices 106A, 106B, etcetera, through 106N. Each of the user devices may be referred to herein as a “user equipment” (UE) or UE device. Thus, the user devices 106 are referred to as UEs or UE devices.

[0034] The base station (BS) 102A may be a base transceiver station (BTS) or cell site (a “cellular base station”) and may include hardware that enables wireless communication with the UEs 106A through 106N.

[0035] The communication area (or coverage area) of the base station may be referred to as a “cell.” The base station 102A and the UEs 106 may be configured to communicate over the transmission medium using any of various radio access technologies (RATs), also referred to as wireless communication technologies, or telecommunication standards, such as GSM, UMTS (associated with, for example, WCDMA or TD-SCDMA air interfaces), LTE, LTE-Advanced (LTE-A), 5G new radio (5G NR), HSPA, 3GPP2 CDMA2000 (e g., IxRTT, IxEV-DO, HRPD, eHRPD), etcetera. Note that if the base station 102A is implemented in the context of LTE, it may alternately be referred to as an ‘eNodeB’ or ‘eNB’. Note that if the base station 102A is implemented in the context of 5G NR, it may alternately be referred to as ‘gNodeB’ or ‘gNB’. A next generation eNB (ng-eNB) may comprise an enhanced version of eNB that connects 5G UE to 5G core network using 4G LTE air interface.

[0036] As shown, the base station 102A may also be equipped to communicate with a network 100 (e.g., a core network of a cellular service provider, a telecommunication network such as a public switched telephone network (PSTN), and/or the Internet, among various possibilities). Thus, the base station 102A may facilitate communication between the user devices and/or between the user devices and the network 100. In particular, the cellular base station 102A may provide UEs 106 with various telecommunication capabilities, such as voice, SMS and/or data services. It will be appreciated that in various embodiments, the term network may be utilized to collectively refer to one or more devices and components that form the telecommunications network. For example, reference to the network sending or receiving data to/from a UE may refer to one or more portions of the core network of a cellular service provider and/or one or more base stations. In some such examples, data to send to the UE may be determined by core network components and then relayed to the UE via a base station. In other such examples, data to send to the UE may be determined and sent to the UE by a base station.

[0037] Base station 102A and other similar base stations (such as base stations 102B . . . 102N) operating according to the same or a different cellular communication standard may thus be provided as a network of cells, which may provide continuous or nearly continuous overlapping service to UEs 106A-N and similar devices over a geographic area via one or more cellular communication standards. [0038] Thus, while base station 102A may act as a “serving cell” for UEs 106A-N as illustrated in FIG. 1, each UE 106 may also be capable of receiving signals from (and possibly within communication range of) one or more other cells (which might be provided by base stations 102B-N and/or any other base stations), which may be referred to as “neighboring cells”. Such cells may also be capable of facilitating communication between user devices and/or between user devices and the network 100. Such cells may include “macro” cells, “micro” cells, “pico” cells, and/or cells which provide any of various other granularities of service area size. For example, base stations 102A-B illustrated in FIG. 1 might be macro cells, while base station 102N might be a micro cell. Other configurations are also possible.

[0039] In some embodiments, base station 102A may be a next generation base station, e.g., a 5G New Radio (5G NR) base station, or “gNB”. In some embodiments, a gNB may be connected to a legacy evolved packet core (EPC) network and/or to a NR core (NRC) network. In addition, a gNB cell may include one or more transition and reception points (TRPs). In addition, a UE capable of operating according to 5G NR may be connected to one or more TRPs within one or more gNBs. [0040] Note that a UE 106 may be capable of communicating using multiple wireless communication standards. For example, the UE 106 may be configured to communicate using a wireless networking (e.g., Wi-Fi) and/or peer-to-peer wireless communication protocol (e.g., Bluetooth, Wi-Fi peer-to-peer, etc.) in addition to at least one cellular communication protocol (e.g., GSM, UMTS (associated with, for example, WCDMA or TD-SCDMA air interfaces), LTE, LTE-A, 5G NR, HSPA, 3GPP2 CDMA2000 (e.g., IxRTT, IxEV-DO, HRPD, eHRPD), etc ). The UE 106 may also or alternatively be configured to communicate using one or more global navigational satellite systems (GNSS, e.g., GPS or GLONASS), one or more mobile television broadcasting standards (e.g., ATSC-M/H or DVB-H), and/or any other wireless communication protocol, if desired. Other combinations of wireless communication standards (including more than two wireless communication standards) are also possible. [0041] FIG. 2 illustrates user equipment 106 (e.g., one of the devices 106A through 106N) in communication with a base station 102, according to some embodiments. The UE 106 may be a device with cellular communication capability such as a mobile phone, a hand-held device, a computer or a tablet, or virtually any type of wireless device.

[0042] The UE 106 may include a processor that is configured to execute program instructions stored in memory. The UE 106 may perform any of the method embodiments described herein by executing such stored instructions. Alternatively, or in addition, the UE 106 may include a programmable hardware element such as an FPGA (field-programmable gate array) that is configured to perform any of the method embodiments described herein, or any portion of any of the method embodiments described herein.

[0043] The UE 106 may include one or more antennas for communicating using one or more wireless communication protocols or technologies. In some embodiments, the UE 106 may be configured to communicate using, for example, 5G NR, CDMA2000 (IxRTT/lxEV- DO/HRPD/eHRPD), or LTE using a single shared radio and/or GSM or LTE using the single shared radio. The shared radio may couple to a single antenna, or may couple to multiple antennas (e.g., for MIMO) for performing wireless communications. In general, a radio may include any combination of a baseband processor, analog RF signal processing circuitry (e.g., including filters, mixers, oscillators, amplifiers, etc.), or digital processing circuitry (e.g., for digital modulation as well as other digital processing). Similarly, the radio may implement one or more receive and transmit chains using the aforementioned hardware. For example, the UE 106 may share one or more parts of a receive and/or transmit chain between multiple wireless communication technologies, such as those discussed above.

[0044] In some embodiments, the UE 106 may include separate transmit and/or receive chains (e.g., including separate antennas and other radio components) for each wireless communication protocol with which it is configured to communicate. As a further possibility, the UE 106 may include one or more radios which are shared between multiple wireless communication protocols, and one or more radios which are used exclusively by a single wireless communication protocol. For example, the UE 106 might include a shared radio for communicating using either of LTE or 5G NR (or LTE or IxRTTor LTE or GSM), and separate radios for communicating using each of Wi-Fi and Bluetooth. Other configurations are also possible.

[0045] FIG. 3 illustrates an example simplified block diagram of a communication device 106, according to some embodiments. It is noted that the block diagram of the communication device of FIG. 3 is only one example of a possible communication device. According to embodiments, communication device 106 may be a user equipment (UE) device, a mobile device or mobile station, a wireless device or wireless station, a desktop computer or computing device, a mobile computing device (e.g., a laptop, notebook, or portable computing device), a tablet and/or a combination of devices, among other devices. As shown, the communication device 106 may include a set of components 300 configured to perform core functions. For example, this set of components may be implemented as a system on chip (SOC), which may include portions for various purposes. Alternatively, this set of components 300 may be implemented as separate components or groups of components for the various purposes. The set of components 300 may be coupled (e.g., communicatively; directly or indirectly) to various other circuits of the communication device 106. [0046] For example, the communication device 106 may include various types of memory (e.g., including NAND flash 310), an input/output interface such as connector I/F 320 (e.g., for connecting to a computer system; dock; charging station; input devices, such as a microphone, camera, keyboard; output devices, such as speakers; etc.), the display 360, which may be integrated with or external to the communication device 106, and cellular communication circuitry 330 such as for 5G NR, LTE, GSM, etc., and short to medium range wireless communication circuitry 329 (e.g., Bluetooth™ and WLAN circuitry). In some embodiments, communication device 106 may include wired communication circuitry (not shown), such as a network interface card, e.g., for Ethernet.

[0047] The cellular communication circuitry 330 may couple (e.g., communicatively; directly or indirectly) to one or more antennas, such as antennas 335 and 336 as shown. The short to medium range wireless communication circuitry 329 may also couple (e.g., communicatively; directly or indirectly) to one or more antennas, such as antennas 337 and 338 as shown. Alternatively, the short to medium range wireless communication circuitry 329 may couple (e.g., communicatively; directly or indirectly) to the antennas 335 and 336 in addition to, or instead of, coupling (e.g., communicatively; directly or indirectly) to the antennas 337 and 338. The short to medium range wireless communication circuitry 329 and/or cellular communication circuitry 330 may include multiple receive chains and/or multiple transmit chains for receiving and/or transmitting multiple spatial streams, such as in a multiple-input multiple output (MIMO) configuration.

[0048] In some embodiments, as further described below, cellular communication circuitry 330 may include dedicated receive chains (including and/or coupled to, e.g., communicatively; directly or indirectly, dedicated processors and/or radios) for multiple radio access technologies (RATs) (e.g., a first receive chain for LTE and a second receive chain for 5G NR). In addition, in some embodiments, cellular communication circuitry 330 may include a single transmit chain that may be switched between radios dedicated to specific RATs. For example, a first radio may be dedicated to a first RAT, e.g., LTE, and may be in communication with a dedicated receive chain and a transmit chain shared with an additional radio, e.g., a second radio that may be dedicated to a second RAT, e.g., 5G NR, and may be in communication with a dedicated receive chain and the shared transmit chain.

[0049] The communication device 106 may also include and/or be configured for use with one or more user interface elements. The user interface elements may include any of various elements, such as display 360 (which may be a touchscreen display), a keyboard (which may be a discrete keyboard or may be implemented as part of a touchscreen display), a mouse, a microphone and/or speakers, one or more cameras, one or more buttons, and/or any of various other elements capable of providing information to a user and/or receiving or interpreting user input. [0050] The communication device 106 may further include one or more smart cards 345 that include SIM (Subscriber Identity Module) functionality, such as one or more UICC(s) (Universal Integrated Circuit Card(s)) cards 345.

[0051] As shown, the SOC 300 may include processor(s) 302, which may execute program instructions for the communication device 106 and display circuitry 304, which may perform graphics processing and provide display signals to the display 360. The processor(s) 302 may also be coupled to memory management unit (MMU) 340, which may be configured to receive addresses from the processor(s) 302 and translate those addresses to locations in memory (e.g., memory 306, read only memory (ROM) 350, NAND flash memory 310) and/or to other circuits or devices, such as the display circuitry 304, short range wireless communication circuitry 329, cellular communication circuitry 330, connector I/F 320, and/or display 360. The MMU 340 may be configured to perform memory protection and page table translation or set up. In some embodiments, the MMU 340 may be included as a portion of the processor(s) 302.

[0052] As noted above, the communication device 106 may be configured to communicate using wireless and/or wired communication circuitry. The communication device 106 may be configured to transmit a request to attach to a first network node operating according to the first RAT (e.g., 5G NR, 4G UTE, Bluetooth, Wi-Fi, etcetera) and transmit an indication that the wireless device is capable of maintaining substantially concurrent connections with the first network node and a second network node that operates according to the second RAT (e.g., 5G NR, 4G UTE, Bluetooth, Wi-Fi, etcetera). The wireless device may also be configured transmit a request to attach to the second network node. The request may include an indication that the wireless device is capable of maintaining substantially concurrent connections with the first and second network nodes. Further, the wireless device may be configured to receive an indication that dual connectivity with the first and second network nodes has been established.

[0053] As described herein, the communication device 106 may include hardware and software components for implementing the above features for supporting multi -hop transmissions. The processor 302 of the communication device 106 may be configured to implement part or all of the features described herein, e.g., by executing program instructions stored on a memory medium (e.g., a non-transitory computer-readable memory medium). Alternatively (or in addition), processor 302 may be configured as a programmable hardware element, such as an FPGA (Field Programmable Gate Array), or as an ASIC (Application Specific Integrated Circuit). Alternatively (or in addition) the processor 302 of the communication device 106, in conjunction with one or more of the other components 300, 304, 306, 310, 320, 329, 330, 340, 345, 350, 360 may be configured to implement part or all of the features described herein.

[0054] In addition, as described herein, processor 302 may include one or more processing elements. Thus, processor 302 may include one or more integrated circuits (ICs) that are configured to perform the functions of processor 302. In addition, each integrated circuit may include circuitry (e.g., first circuitry, second circuitry, etc.) configured to perform the functions of processor(s) 302.

[0055] Further, as described herein, cellular communication circuitry 330 and short range wireless communication circuitry 329 may each include one or more processing elements. In other words, one or more processing elements may be included in cellular communication circuitry 330 and, similarly, one or more processing elements may be included in short range wireless communication circuitry 329. Thus, cellular communication circuitry 330 may include one or more integrated circuits (ICs) that are configured to perform the functions of cellular communication circuitry 330. In addition, each integrated circuit may include circuitry (e.g., first circuitry, second circuitry, etc.) configured to perform the functions of cellular communication circuitry 330. Similarly, the short range wireless communication circuitry 329 may include one or more ICs that are configured to perform the functions of short range wireless communication circuitry 329. In addition, each integrated circuit may include circuitry (e.g., first circuitry, second circuitry, etc.) configured to perform the functions of short range wireless communication circuitry 329.

[0056] FIG. 4 illustrates an example block diagram of a base station 102, according to some embodiments. It is noted that the base station of FIG. 4 is merely one example of a possible base station. As shown, the base station 102 may include processor(s) 404 which may execute program instructions for the base station 102. The processor(s) 404 may also be coupled to memory management unit (MMU) 440, which may be configured to receive addresses from the processor(s) 404 and translate those addresses to locations in memory (e.g., memory 460 and read only memory (ROM) 450) or to other circuits or devices.

[0057] The base station 102 may include at least one network port 470. The network port 470 may be configured to couple to a telephone network and provide a plurality of devices, such as UE devices 106, access to the telephone network as described above in FIGS. 1 and 2.

[0058] The network port 470 (or an additional network port) may also or alternatively be configured to couple to a cellular network, e.g., a core network of a cellular service provider. The core network may provide mobility related services and/or other services to a plurality of devices, such as UE devices 106. In some cases, the network port 470 may couple to a telephone network via the core network, and/or the core network may provide a telephone network (e.g., among other UE devices serviced by the cellular service provider).

[0059] In some embodiments, base station 102 may be a next generation base station, e.g., a 5G New Radio (5G NR) base station, or “gNB”. In such embodiments, base station 102 may be connected to a legacy evolved packet core (EPC) network and/or to a NR core (NRC) network. In addition, base station 102 may be considered a 5G NR cell and may include one or more transition and reception points (TRPs). In addition, a UE capable of operating according to 5G NR may be connected to one or more TRPs within one or more gNBs. [0060] The base station 102 may include at least one antenna 434, and possibly multiple antennas, such as an array of antennas (see e.g., FIG. 12). The at least one antenna 434 may be configured to operate as a wireless transceiver and may be further configured to communicate with UE devices 106 via radio 430. The antenna 434 communicates with the radio 430 via communication chain 432. Communication chain 432 may be a receive chain, a transmit chain or both. The radio 430 may be configured to communicate via various wireless communication standards, including, but not limited to, 5G NR, LTE, LTE-A, GSM, UMTS, CDMA2000, Wi-Fi, etc.

[0061] The base station 102 may be configured to communicate wirelessly using multiple wireless communication standards. In some instances, the base station 102 may include multiple radios, which may enable the base station 102 to communicate according to multiple wireless communication technologies. For example, as one possibility, the base station 102 may include an LTE radio for performing communication according to LTE as well as a 5G NR radio for performing communication according to 5G NR. In such a case, the base station 102 may be capable of operating as both an LTE base station and a 5G NR base station. As another possibility, the base station 102 may include a multi-mode radio which is capable of performing communications according to any of multiple wireless communication technologies (e.g., 5G NR and Wi-Fi, LTE and Wi-Fi, LTE and UMTS, LTE and CDMA2000, UMTS and GSM, etc.).

[0062] As described further subsequently herein, the BS 102 may include hardware and software components for implementing or supporting implementation of features described herein. The processor 404 of the base station 102 may be configured to implement or support implementation of part or all of the methods described herein, e.g., by executing program instructions stored on a memory medium (e.g., a non -transitory computer-readable memory medium). Alternatively, the processor 404 may be configured as a programmable hardware element, such as an FPGA (Field Programmable Gate Array), or as an ASIC (Application Specific Integrated Circuit), or a combination thereof. Alternatively (or in addition) the processor 404 of the BS 102, in conjunction with one or more of the other components 430, 432, 434, 440, 450, 460, 470 may be configured to implement or support implementation of part or all of the features described herein.

[0063] In addition, as described herein, processor(s) 404 may be comprised of one or more processing elements. In other words, one or more processing elements may be included in processor(s) 404. Thus, processor(s) 404 may include one or more integrated circuits (ICs) that are configured to perform the functions of processor(s) 404. In addition, each integrated circuit may include circuitry (e.g., first circuitry, second circuitry, etc.) configured to perform the functions of processor(s) 404.

[0064] Further, as described herein, radio 430 may be comprised of one or more processing elements. In other words, one or more processing elements may be included in radio 430. Thus, radio 430 may include one or more integrated circuits (ICs) that are configured to perform the functions of radio 430. In addition, each integrated circuit may include circuitry (e.g., first circuitry, second circuitry, etc.) configured to perform the functions of radio 430. [0065] FIG. 5 illustrates an example simplified block diagram of cellular communication circuitry, according to some embodiments. It is noted that the block diagram of the cellular communication circuitry of FIG. 5 is only one example of a possible cellular communication circuit. According to embodiments, cellular communication circuitry 330 may be include in a communication device, such as communication device 106 described above. As noted above, communication device 106 may be a user equipment (UE) device, a mobile device or mobile station, a wireless device or wireless station, a desktop computer or computing device, a mobile computing device (e.g., a laptop, notebook, or portable computing device), a tablet and/or a combination of devices, among other devices.

[0066] The cellular communication circuitry 330 may couple (e.g., communicatively; directly or indirectly) to one or more antennas, such as antennas 335 a-b and 336 as shown. In some embodiments, cellular communication circuitry 330 may include dedicated receive chains (including and/or coupled to, e.g., communicatively; directly or indirectly, dedicated processors and/or radios) for multiple RATs (e.g., a first receive chain for LTE and a second receive chain for 5G NR). For example, as shown in FIG. 5, cellular communication circuitry 330 may include a modem 510 and a modem 520. Modem 510 may be configured for communications according to a first RAT, e.g., such as LTE or LTE-A, and modem 520 may be configured for communications according to a second RAT, e.g., such as 5G NR.

[0067] As shown, modem 510 may include one or more processors 512 and a memory 516 in communication with processors 512. Modem 510 may be in communication with a radio frequency (RF) front end 530. RF front end 530 may include circuitry for transmitting and receiving radio signals. For example, RF front end 530 may include receive circuitry (RX) 532 and transmit circuitry (TX) 534. In some embodiments, receive circuitry 532 may be in communication with downlink (DL) front end 550, which may include circuitry for receiving radio signals via antenna 335a.

[0068] Similarly, modem 520 may include one or more processors 522 and a memory 526 in communication with processors 522. Modem 520 may be in communication with an RF front end 540. RF front end 540 may include circuitry for transmitting and receiving radio signals. For example, RF front end 540 may include receive circuitry 542 and transmit circuitry 544. In some embodiments, receive circuitry 542 may be in communication with DL front end 560, which may include circuitry for receiving radio signals via antenna 335b.

[0069] In some embodiments, a switch 570 may couple transmit circuitry 534 to uplink (UL) front end 572. In addition, switch 570 may couple transmit circuitry 544 to UL front end 572. UL front end 572 may include circuitry for transmitting radio signals via antenna 336. Thus, when cellular communication circuitry 330 receives instructions to transmit according to the first RAT (e.g., as supported via modem 510), switch 570 may be switched to a first state that allows modem 510 to transmit signals according to the first RAT (e.g., via a transmit chain that includes transmit circuitry 534 and UL front end 572). Similarly, when cellular communication circuitry 330 receives instructions to transmit according to the second RAT (e.g., as supported via modem 520), switch 570 may be switched to a second state that allows modem 520 to transmit signals according to the second RAT (e.g., via a transmit chain that includes transmit circuitry 544 and UL front end 572).

[0070] As described herein, the modem 510 may include hardware and software components for implementing the above features or for supporting multi-hop transmissions, as well as the various other techniques described herein. The processors 512 may be configured to implement part or all of the features described herein, e.g., by executing program instructions stored on a memory medium (e.g., a non-transitory computer-readable memory medium). Alternatively (or in addition), processor 512 may be configured as a programmable hardware element, such as an FPGA (Field Programmable Gate Array), or as an ASIC (Application Specific Integrated Circuit). Alternatively (or in addition) the processor 512, in conjunction with one or more of the other components 530, 532, 534, 550, 570, 572, 335a, 335b, and 336 may be configured to implement part or all of the features described herein.

[0071] In addition, as described herein, processors 512 may include one or more processing elements. Thus, processors 512 may include one or more integrated circuits (ICs) that are configured to perform the functions of processors 512. In addition, each integrated circuit may include circuitry (e.g., first circuitry, second circuitry, etc.) configured to perform the functions of processors 512.

[0072] As described herein, the modem 520 may include hardware and software components for implementing the above features for supporting multi-hop transmissions, as well as the various other techniques described herein. The processors 522 may be configured to implement part or all of the features described herein, e.g., by executing program instructions stored on a memory medium (e.g., a non-transitory computer-readable memory medium). Alternatively (or in addition), processor 522 may be configured as a programmable hardware element, such as an FPGA (Field Programmable Gate Array), or as an ASIC (Application Specific Integrated Circuit). Alternatively (or in addition) the processor 522, in conjunction with one or more of the other components 540, 542, 544, 550, 560, 570, 572, 335a, 335b, and 336 may be configured to implement part or all of the features described herein.

[0073] In addition, as described herein, processors 522 may include one or more processing elements. Thus, processors 522 may include one or more integrated circuits (ICs) that are configured to perform the functions of processors 522. In addition, each integrated circuit may include circuitry (e.g., first circuitry, second circuitry, etcetera) configured to perform the functions of processors 522.

[0074] FIG. 6 illustrates a network message 602 comprising a plurality of information elements (IES) 604a, 604b, 604c, 604d (collectively referred to as IES 604). In various embodiments, a variety of network messages 602 composed of one or more information elements may be utilized for communication between different components. In various such embodiments, one or more network messages 602 of one or more formats may be exchanged between the one or more UEs and one or more network components to perform one or more procedures or techniques disclosed hereby. For example, granting and dynamically adjusting the utilization of granted resources for multi-hop transmissions based on availability of data from preceding nodes and local channel conditions may involve the exchange of several network messages 602 between UEs and/or a BS. It will be appreciated that the network message 602 and IES 604 may come in a variety of formats and carry a variety of information. Oftentimes, various standards and technical specifications define the various network messages 602, IEs 604, and procedures, such as 3GPP technical specifications (e.g., TS 38.300 and TS 38.351). Embodiments are not limited in this context.

[0075] Various techniques for providing resource-efficient techniques of dynamically adjusting collective channel resources across multiple hop transmissions that utilize UE-to-UE relays, such as based on current QoS requirements and utilizing statistical multiplexing, are described in more detail below. In many embodiments, dynamic local adaptation of overall multi-hop transmission resource scheduling may occur for various UEs participating in a multi-hop transmission. Several embodiments include a hybrid mechanism that utilizes components of centralized and UE autonomous scheduling for communications within a UE cluster (also referred to as a UE mesh group or UE group). In several such embodiments, each UE in a UE cluster may belong to a common mesh sub-network. In many embodiments, UEs may be allocated resources for a certain number of retransmissions for a multi-hop transmission within a UE cluster, but then surrender resources that are not needed. In several embodiments, the number of retransmission attempts per hop may be adjusted in the case of autonomous retransmissions to satisfy QoS requirements of the traffic. In several such embodiments, packet forwarding is supported at each hop when the packet is correctly received, even before the allowed number of retransmission attempts.

[0076] In many embodiments, UEs may dynamically adjust the utilization of granted resources for multi-hop transmissions based on availability of data from preceding nodes and/or local channel conditions. For example, early resources may be filled with dummy/null data when the UE is not yet ready to transmit a data packet, such as due to transmission on the previous hop being incomplete. In another example, resources may be surrendered at the end of an allocation when an acknowledgement (e.g., ACK) is received for the data packet transmission. In some such examples, the BS may reassign at least a portion of the set of surrendered resources to a transmission separate from the multi-hop transmission. In yet another example, various parameters, such as RLC mode or number of transmission attempts, may be dynamically adjusted for different hops based on data packet characteristics and/or local channel conditions.

[0077] In these and other ways, components/techniques described hereby may provide many technical advantages. For instance, the computer-based techniques of the current disclosure improve the functioning of a telecommunications system as compared to conventional approaches because the techniques enable robust support for multi-hop transmissions that can improve accessibility and coverage of telecommunication networks, reduce overhead, and provide expanded capabilities versus conventional approaches. Further, embodiments disclosed hereby can be practically utilized to improve the functioning of a computer and/or to improve a variety of technical fields including telecommunications, 5G networks, mesh networks, multi-hop transmissions, URLLC, D2D communications, and/or UE-to-UE relays. [0078] FIGS. 7A and 7B illustrate exemplary operating environments 700a, 700b for multi-hop transmissions according to some embodiments. More specifically, FIG. 7A illustrates an operating environment 700a for multi-hop transmissions between a source UE 706 and a destination UE 710 in a single UE cluster 702 and FIG. 7B illustrates an operating environment 700b for multi -hop transmissions between a source UE 720 in a first UE cluster 714a and a destination UE 726 in a second UE cluster 714b. It will be appreciated that one or more components of FIGS. 7A and/or 7B may be the same or similar to one or more other components disclosed hereby. For example, BS 704, BS 716a, and/or BS 716b may be the same or similar to BS 102. In another example, network components 718 may comprise one or more portions of network 100. Further, aspects discussed with respect to various components in FIGS. 7A and/or 7B may be implemented by one or more other components from one or more other embodiments without departing from the scope of this disclosure. Embodiments are not limited in this context.

[0079] Referring to FIG. 7A, operating environment 700a includes a UE cluster 702 and a BS 704. The UE cluster 702 includes a source UE 706, a destination UE 710, and intermediate UEs 708a, 708b (collectively referred to as intermediate UEs 708). In embodiments described hereby, each UE cluster has an intermediate UE communicatively coupled to a BS. The intermediate UE communicatively coupled to the BS is referred to as the primary UE. The primary UE may generally control the UE cluster, connect the UE cluster with the core network via a BS, and serve as a collection and distribution point for control information exchanged with the BS and/or core network. In some embodiments, the primary UE may control the UE based on data received from the BS.

[0080] In the illustrated embodiment, intermediate UE 708b of UE cluster 702 is communicatively coupled to the BS 704 and, therefore, comprises a primary UE 712. In operation, a multi -hop transmission may be utilized to enable the source UE 706 to communicate information, such as one or more messages (e.g., packets comprising payload data), to the destination UE 710 via the intermediate UEs 708. For example, payload data may be sent from source UE 706 to intermediate UE 708a in a first hop, the payload data may be sent from intermediate UE 708a to intermediate UE 708b in a second hop, and the payload data may be sent from intermediate UE 708b to destination UE 710 in a third hop.

[0081] Generally, a multi-hop transmission may operate as follows. Initially, the source UE 706 may transmit an indication to the primary UE 712 (e.g., via intermediate UE 708a) that it wants to transmit data to the destination UE 710. In response, the primary UE 712 may request resources from the BS 704 for the multi-hop transmission. In various embodiments, the amount of resources may depend on one or more of the number of hops, the required reliability (e.g., QoS), a measure of statistical gain utilized to reduce the aggregate total resources. The required QoS may be utilized to determine the max number of transmission attempts per hop.

[0082] Each UE in the multi-hop transmission chain (i.e., source UE 706 and intermediate UEs 708) may be provided with individual transmission resources for initial and retransmissions. Indications of the provided resources (e.g., slots) may be sent to the primary UE 712 by the BS 704 and then relayed to the various UEs in the multi-hop transmission chain. In some embodiments, the number of transmission attempts per hop (e.g., 1-5) may be different depending on channel conditions (e.g., channel state information (CSI)). In many embodiments, UEs may be provided with multiple transmission resources to use depending on when the arriving packet is successfully decoded.

[0083] After the initial transmission is completed, it may be determined that some transmission resources could remain unused after one or more hops are complete (e.g., after the final hop to destination UE 710). Accordingly, in response to the unused resources, the primary UE 712 may allow additional transmission attempts on remaining hops, if needed, or limit the number of transmission attempts per the initial allotment, and surrender future unused resources to the BS 704. In many embodiments, a UE may utilize M out of N granted resources, where M<N, for data transmissions and either fill non-payload data (e.g., dummy or null data) in unused resources and/or surrender the unused resources. Specific procedures for multi-hop transmissions will be described in more detail below, such as with respect to FIGS. 8-11.

[0084] Turning to FIG. 7B, in some embodiments, the source and destination UEs may be in different UE clusters. Accordingly, operating environment 700B includes a first UE cluster 714a, a first BS 716a, one or more network components 718, a second BS 716b, and a second UE cluster 714b. The network components 718 communicatively couple the first BS 716a and the second BS 716b. The first UE cluster 714a includes a source UE 720 and intermediate UEs 722a, 722b (collectively referred to as intermediate UEs 722). The intermediate UE 722b comprises a first primary UE 728a communicatively coupled to the first BS 716a. The second UE cluster 714b includes intermediate UEs 724a, 724b (collectively referred to as intermediate UEs 724) and a destination UE 726. The intermediate UE 724a comprises a second primary UE 728b communicatively coupled to the second BS 716b. In operation, multi-hop transmissions may be utilized to enable the source UE 720 may communicate information, such as one or more messages (e.g., packets comprising payload data) to the destination UE 726 via the intermediate UEs 722, BS 716a, network components 718, BS 716b, and intermediate UEs 724. For example, payload data may be sent from source UE 720 to intermediate UE 722a in a first hop and the payload data may be sent from intermediate UE 722a to intermediate UE 722b in a second hop, the payload data may be communicated from intermediate UE 722b to intermediate UE 724a via BS 716a, network components 718, and BS 716b, the payload data may be sent from intermediate UE 724a to intermediate UE 724b in a third hop, and the payload data may be sent from intermediate UE 724b to destination UE 726 in a fourth hop.

[0085] In various embodiments, when the source and destination UEs are in different UE clusters controlled by different primary UEs. The primary UE 728b in the UE cluster 714a with the source UE 720 may be referred to as the source primary UE and the primary UE 728a in the UE cluster 714b with the destination UE 726 may be referred to as the destination primary UE. The source primary UE 728a may communicate with the destination primary UE 728b either directly (e.g., if they are connected via sidelink, or via one or more BSs if there is no direct sidelink connection. For example, the source primary UE and the destination primary UE may be coupled to the same BS. When the destination UE does not belong to the same UE cluster managed by the source primary UE, the source primary UE may request assistance from the BS in identifying and communicating with the destination primary UE that manages the UE cluster comprising the destination UE.

[0086] FIG. 8 illustrates an exemplary process diagram 800 for multi-hop transmissions and local resource reconfiguration in an acknowledge mode according to some embodiments. Process diagram 800 includes a source UE 802, intermediate UEs 804, 806, a destination UE 808, and a BS 810. The intermediate UE 806 may be the primary UE 806. In various embodiments, process diagram 800 may illustrate various messages sent and/or received to implement a multi-hop transmission using an acknowledge mode. In many embodiments, dynamic local adaptation of overall multi -hop transmission resource scheduling may occur for various UEs participating in a multi-hop transmission. This may include the transmission of non-payload data (e.g., dummy data, null data, or a predetermined bit sequence) when a UE is not ready to transmit and surrendering unused resources when an ACK is received. In several embodiments, a UE may only use a subset of the granted resources for data transmissions and either fill non-payload data in unused resources (e.g., when unused resources occur before payload data is available) or surrender the unused resources (e.g., after the payload data has been sent). It will be appreciated that one or more components of FIG. 8 may be the same or similar to one or more other components disclosed hereby. For example, primary UE 806 may be the same or similar to one or more of primary UE 712, primary UE 728a, and primary UE 728b. In another example, BS 810 may be the same or similar to one or more of BS 704, BS 716a, and BS 716b. Further, aspects discussed with respect to various components in FIG. 8 may be implemented by one or more other components from one or more other embodiments without departing from the scope of this disclosure. Embodiments are not limited in this context.

[0087] Initially, the source UE 802 may transmit a mesh buffer status report (BSR) message to the BS 810 indicating the source UE 802 wants to transmit data to the destination UE 808, which may occur over multiple hops. For example, as shown in the illustrated embodiment, at resource acquisition process 812a, source UE 802 may transmit a mesh buffer status report (BSR) to the primary UE 806, such as via intermediate UE 804. The mesh BSR may include one or more of the following fields including a sub-network ID, a destination device ID, a source device ID, a buffer size, a QoS, a periodicity, and a max repetition. The sub-network ID may be assigned when the primary UE (e.g., primary UE 806) initializes the mesh sub-network of the UE cluster. Thus, the sub-network ID may be utilized as an identifier for the UE cluster performing at least a portion of the multi-hop transmission. The destination device ID may identify the destination UE (e.g., destination UE 808). The destination device ID may be unique within the mesh sub-network. The source device ID may identify the source UE (e.g., source UE 802). The buffer size may be an indication of (e.g., a pointer towards) an entry within a predefined table, which may include values in units of bytes (see e.g., TS 38.321). The QoS may refer to an appropriate data prioritization identifier and/or packet qualities, such as a 5G QoS identifier (5QI) or logical channel group (LCG). In various embodiments, the UE may report the BSR per LCG, such as depending on the BSR format (e.g., long/short/truncated). The periodicity and maximum repetition may be utilized when a persistent grant is requested.

[0088] The primary UE 806 may determine the amount of channel resources needed for the multihop transmission from the source UE 802 to the destination UE 808 and, at resource acquisition process 812b, send a mesh resource request message to the BS 810. In various embodiments, the mesh resource request message may include the time domain resources (e.g., amount of time) and/or frequency domain resources needed for the multi-hop transmission over multiple self-contained slots. In the illustrated embodiment, the mesh resource request may include the subnetwork ID, a frequency domain resource request, and a time domain resource request. At resource acquisition process 812c, the BS 810 may send a mesh resource response containing a grant with resources for the multi-hop transmissions from the source UE 802 to the destination UE 808. This may include initial resource assignments of resources for initial transmissions and a configured number of retransmissions on each hop between the source UE 802 and the destination UE 808.

[0089] In various embodiments, the mesh resource response sent at resource acquisition process 812c may include the subnetwork ID, a frequency domain resource assignment, a time domain resource assignment, and a start time for the multi-hop transmission. In the illustrated embodiment, the resource grant may include indication of slots 814a, 814b (collectively referred to as slots 814) for an initial transmission and a retransmission from source UE 802 to intermediate UE 804 in the first hop; the resource grant may include indication of slots 820a, 820b, 820c (collectively referred to as slots 820) for an initial transmission and two retransmissions from intermediate UE 804 to primary UE 806 in the second hop; and the resource grant may include indication of slots 828a, 828b, 828c, 828d (collectively referred to as slots 828) for an initial transmission and three retransmissions from primary UE 806 to destination UE 808 in the third hop.

[0090] The primary UE 806 may then distribute the resource allocations to the other UEs at resource acquisition processes 812d, 812e, 812f For example, the primary UE 806 may first transmit multi-hop physical downlink control channel (PDCCH) configuration messages to the source UE 802, intermediate UE 804, and destination UE 808. The PDCCH configuration messages may indicate which resources the UEs should monitor for subsequent MCI messages. The primary UE 806 may then send mesh control information (MCI) messages to the source UE 802, intermediate UE 804, and destination UE 808. The MCI messages may include the resource grants for the initial transmission and configured maximum number of re-transmissions on each hop in the end-to-end route from the source to the destination UE. In various embodiments, each of the MCI messages may include the subnetwork ID, the respective frequency domain resource assignment, the respective time domain resource assignment, and the modulation and coding scheme (MCS). [0091] As will be described in more detail below, each UE may then perform payload data transmission on the assigned resources for the initial transmission, and, if a negative acknowledgement (NACK) is received from the receiving UE for that particular transmission, or if no ACK is received from the receiving UE, then retransmissions are performed on the previously allocated resources until the maximum configured limit is reached or an ACK is received. Further, an intermediate UE may transmit non-payload data (e.g., null or dummy data) on the previously allocated resources meant for initial data transmission of payload data if the payload data transmission on the previous hop is unavailable by the scheduled start of transmission (e.g., not received, not decoded, and/or not prepared/processed for transmission in the next hop).

[0092] The non-payload data (e.g., null or dummy data) may include a preconfigured bit sequence to ensure that the receiver does not soft-combine the non-payload data with the payload data. When the payload data transmission on the final hop (i.e., from primary UE 806 to destination UE 808) is acknowledged by the destination UE, then the primary UE 806 may release the unused resources to the BS 810 via a mesh resource indication message including the surrender indication. In some embodiments, one or more of the intermediate UEs and the destination UE may send an MCI indication to the primary UE. In some such embodiments, the MCI indications are sent to the primary UE as an early indication of the surrendered resources. In various embodiments, the early indications may enable resources to be surrendered before the payload data transmission on the final hop is completed. In many embodiments, additional resources may be initially assigned for later hops in a multi-hop transmission than earlier hops due to an increasing likelihood that the payload data will not be available for transmission in the initial slots allocated for the later hops due to the increasing chance of a delay in an earlier hop. In other words, later hops require more preceding hops to have been successfully completed, which results in a higher chance that one of the preceding hops will require retransmission resources. Additionally, the chances of requiring retransmissions on each hop are low, and therefore the total amount of resources allocated for the multi-hop transmission may be reduced from the absolute worst-case situation, i.e., the sum of resources assuming each transmission hop requires the maximum number of retransmissions for successful transmission. In some embodiments, these concepts may correspond to the measure of statistical gain utilized to reduce the aggregate total resources. Statistical multiplexing may correspond to the overlap in slots, such as slot 814b and slot 820a.

[0093] Referring back to the process diagram 800 in the context of performing payload data transmissions on the assigned resources, initially source UE 802 may send payload data transmission 816 to intermediate UE 804 in slot 814a for the first hop. In response to payload data transmission 816, source UE 802 may receive ACK 818 indicating that intermediate UE 804 received and successfully decoded the payload data. In the illustrated embodiment, slot 814b is not needed for payload data transmission from source UE 802 to intermediate UE 804 because payload data transmission 816 was successful. However, if payload data transmission 816 had not been successful, then slot 814b could be utilized for a retransmission.

[0094] Next, intermediate UE 804 may perform payload data transmission 822a to primary UE 806 in slot 820a for the second hop. However, primary UE 806 may not receive or successfully decode the payload data in payload data transmission 822a, Accordingly, primary UE 806 may send NACK 824 to intermediate UE 804 to indicate the payload data was not received or successfully decoded. In response, intermediate UE 804 may perform payload data transmission 822b to retransmit the payload data to primary UE 806 in slot 820b for the second hop. Intermediate UE 804 may then receive ACK 826 indicating that primary UE 806 received and successfully decoded the payload data. In the illustrated embodiment, slot 820c is not needed for payload data transmission from intermediate UE 804 to primary UE 806 because payload data transmission 822b was successful. However, if payload data transmission 822b had not been successful, then 820c could be utilized for a retransmission. Further, in some embodiments, if payload data transmission 822a had been successful, then slot 820b could be utilized to send an MCI indication to primary UE 806 to surrender slot 820c as an unused resource. More generally, in various embodiments, each UE may send MCI indications regarding unused resources or only UEs with unused resources could send MCI indications.

[0095] Turning to the third hop, primary UE 806 may send non-payload data transmission 830 to destination UE 808 in slot 828a because the payload data was unavailable for transmission to destination UE 808 due to primary UE 806 not successfully receiving the payload data from intermediate UE 804 in slot 820a (and/or processing received payload data in time for transmitting in slot 828a). In response to the non-payload data transmission 830, primary UE 806 may receive ACK 832 from destination UE 808. In slot 828b, primary UE 806 may send payload data transmission 834 to destination UE 808 for the third (and final hop of the multi-hop transmission) and, in response, receive ACK 836 from destination UE 808. Once the destination UE 808 receives and successfully decodes the payload data, the multi -hop transmission is complete.

[0096] After the multi-hop transmission is complete, resource surrender process 838a may be performed, such as in response to slot 828d being an unused resource. Resource surrender process 838a may include destination UE 808 sending an MCI indication to primary UE 806 that identifies slot 828d for resource surrender. In response, primary UE 806 may send a mesh resource indication to BS 810 in slot 828c to surrender slot 828d. In various embodiments, the mesh resource indication may include the subnetwork ID and indication of the surrendered resources.

[0097] In some embodiments, direct communications may be performed between the primary UE 806 and one or more other cluster UEs. For example, the primary UE 806 may transmit one or more of the control messages within the UE cluster (e.g., the multi-hop PDCCH configuration and/or the MCI) in broadcast or multicast mode to reduce the control message overhead and latency. In many embodiments, the final MCI indication message from destination UE 808 to the primary UE 806 in resource surrender process 838a (or other MCI indication messages from other UEs to the primary UE 806) may be sent in broadcast or multicast mode. In several embodiments, the broadcast or multicast message transmission and the actual multi-hop data transmissions may be supported by different configured bands (e.g., low-bands (e.g., frequency resource one (FR1)) for broadcast or multicast control messages (e.g., multi-hop PDCCH configuration, MCI, etc.) between the primary UE 806 and other cluster UEs. Other FRs (e.g., FR2, FR4, etc.) may be utilized for unicast data and corresponding ACK transmissions on individual hops between cluster member UEs. In some embodiments, the broadcast or multicast transmission of control messages may utilize existing multicast or groupcast mechanisms included in NR sidelink specifications (e.g., TS 38.300 and TS 38.351).

[0098] FIG. 9 illustrates an exemplary process diagram 900 for multi-hop transmissions and local resource reconfiguration in an autonomous retransmission mode according to some embodiments. The autonomous retransmission mode may correspond to the MAC layer. Process diagram 900 includes a source UE 902, intermediate UEs 904, 906, destination UE 908, and BS 910. The intermediate UE 906 may be the primary UE 906. In various embodiments, process diagram 900 may illustrate various messages sent and/or received to implement a multi-hop transmission using an autonomous retransmission mode. Generally, process diagram 900 may operate similarly to process diagram 800. However, in autonomous retransmission mode, each UE on the multi-hop route may autonomously retransmit messages (e.g., packets with payload data) up to a preconfigured limit, unless an ACK is received earlier. It will be appreciated that one or more components of FIG. 9 may be the same or similar to one or more other components disclosed hereby. For example, primary UE 906 may be the same or similar to one or more of primary UE 712, primary UE 728a, and primary UE 728b. In another example, BS 910 may be the same or similar to one or more of BS 704, BS 716a, and BS 716b. Further, aspects discussed with respect to various components in FIG. 9 may be implemented by one or more other components from one or more other embodiments without departing from the scope of this disclosure. Embodiments are not limited in this context.

[0099] Under autonomous retransmission mode, the primary UE 906 requests resources from BS 910 for a multi-hop transmission. The amount of resources depends on one or more of the total number of hops, the QoS/reliability requirement (this may be used to determine the autonomous retransmission limit per hop), and a measure of statistical gain utilized to reduce the aggregate total resources. Each UE in the multi-hop transmission chain may be provided with individual transmission resources for a max number of autonomous retransmissions. In various embodiments, the number of autonomous retransmission attempts on each hop may depend on local channel conditions. In some embodiments, UEs may be provided with multiple transmission resources to use depending on when the arriving packet is successfully decoded. Each UE may start transmitting on the next hop as soon as the packet on the previous hop is successfully decoded and/or after a preconfigured number of retransmission attempts. In various embodiments, the UE may optionally send an ACK back to the previous UE to stop further autonomous retransmissions. In several embodiments, the primary UE 906 may surrender additional resources if they remain (or potentially remain) unused. [0100] As previously mentioned the process diagram 900 may be similar to process diagram 800 in various respects. Accordingly, the overall resource acquisition process 912 of process diagram 900 (including resource acquisition processes 912a, 912b, 912c, 912d, 912e, 912f) may proceed the same as the overall resource acquisition process 812 of process diagram 800 (including resource acquisition processes 812a, 812b, 812c, 812d, 812e, 812f) described above.

[0101] During the multi-hop transmission of process diagram 900, each UE may perform multi payload data retransmissions on the assigned resources until an ACK is received from the receiving UE. Any remaining resources for retransmission attempts, after an ACK is received, may remain unutilized for that hop. The ACK may be transmitted in the resources for reverse direction transmission in a self-contained slot. However, in other embodiments, no resources may be allowed for ACK. In such other embodiments, the transmitting UE may continue retransmissions in all the allotted resources up to the preconfigured limit. Further, the receiving UE may correctly receive and decode the payload data using fewer retransmissions. In response, the receiving UE may begin transmissions on the next hop before waiting for all retransmission on the previous hop are completed.

[0102] An intermediate UE (e.g., intermediate UE 904 or primary UE 906) may transmit nonpayload data (e.g., null or dummy data) on the previously allocated resources if the payload data transmission on the previous hop is unavailable by the scheduled start of transmission (e.g., not received, not decoded, and/or not prepared/processed for transmission in the next hop). The nonpayload data (e.g., null or dummy data) may include a preconfigured bit sequence to ensure that the receiver does not soft-combine the non-payload data with the payload data. When the payload data transmission on the final hop (i.e., from primary UE 906 to destination UE 908) is acknowledged by the destination UE 908, then the primary UE 906 may release the unused resources to the BS 910 via a mesh resource indication message including the surrender indication. In some embodiments, one or more of the intermediate UEs and the destination UE may send an MCI indication to the primary UE. In some such embodiments, the MCI indications are sent to the primary UE as an early indication of the surrendered resources. In various embodiments, the early indications may enable resources to be surrendered before the payload data transmission on the final hop is completed. In several embodiments, the BS may reassign at least a portion of the set of surrendered resources to a transmission separate from the multi-hop transmission. In many embodiments, additional resources may be initially assigned for later hops in a multi-hop transmission than earlier hops due to an increasing likelihood that the payload data will not be available for transmission in the initial slots allocated for the later hops due to the increasing chance of a delay in an earlier hop. In other words, later hops require more preceding hops to have been successfully completed, which results in a higher chance that one of the preceding hops will require retransmission resources. Additionally, the chances of requiring retransmissions on each hop are low, and therefore the total amount of resources allocated for the multi-hop transmission may be reduced from the absolute worst-case situation, i.e., the sum of resources assuming each transmission hop requires the maximum number of retransmissions for successful transmission. In some embodiments, these concepts may correspond to the measure of statistical gain utilized to reduce the aggregate total resources. Statistical multiplexing may correspond to the overlap in slots, such as slot 922b and slot 928a.

[0103] Referring back to the process diagram 900 in the context of performing payload data transmissions on the assigned resources, initially source UE 902 may send payload data transmission 918a to intermediate UE 904 in transmission opportunity 916a of slot 914a. The source UE 902 may then send payload data transmission 918b to intermediate UE 904 in transmission opportunity 916b of slot 914a, such as in response to not receiving an ACK after payload data transmission 918a. However, in some embodiments, there may only be a single opportunity to transmit an ACK at the end of each slot. Thus, in some such embodiments, the intermediate UE 904 may have received and successfully decoded payload data transmission 918a. In the illustrated embodiment, source UE 902 may receive ACK 920 and stop retransmitting the payload data. Accordingly, transmission opportunity 916c and transmission opportunity 916d of slot 914b may remain unused. It will be appreciated that in process diagram 900, the dashed-line boxes represent transmission opportunities and the thicker solid arrows represent payload data transmissions although each instance is not labeled. It will also be appreciated that while the presented example shows two transmission opportunities for payload data per slot, the number of transmission opportunities may be configurable. For example, each slot may include three or more transmission opportunities.

[0104] In the second hop, intermediate UE 904 may perform two payload data transmissions in slot 922a. Further, such as in response to a missing ACK 924 not received at the end of slot 922a, intermediate UE 904 may perform two more payload data transmissions in slot 922b and receive ACK 926 at the end of slot 922b. Accordingly, slot 922c may remain unused.

[0105] In the third hop, primary UE 906 may perform non-payload data transmission 930a and nonpayload data transmission 930b in slot 928a in response to the payload data being unavailable for transmission to destination UE 908 in slot 928a. In response to the payload data being available for transmission to the destination UE 908, the primary UE 906 may perform two payload data transmissions in slot 928b and receive ACK 932 at the end of slot 928b.

[0106] After the multi-hop transmission is complete, resource surrender process 934a may be performed, such as in response to slot 928d being an unused resource. Resource surrender process 934a may include destination UE 908 sending an MCI indication to primary UE 906 that identifies slot 928d for resource surrender. In response, primary UE 906 may send a mesh resource indication to BS 910 in slot 928c to surrender slot 928d. In various embodiments, the mesh resource indication may include the subnetwork ID and indication of the surrendered resources. More generally, in various embodiments, each UE may send MCI indications regarding unused resources or only UEs with unused resources may send MCI indications.

[0107] In many embodiments, direct communications may be performed between the primary UE 806 and one or more other cluster UEs. For example, the primary UE 906 may transmit one or more of the control messages within the UE cluster (e.g., the multi-hop PDCCH configuration and/or the MCI) in broadcast or multicast mode to reduce the control message overhead and latency. In many embodiments, the final MCI indication message from destination UE 908 to the primary UE 906 in resource surrender process 934a (or other MCI indication messages from other UEs to the primary UE 906) may be sent in broadcast or multicast mode. In several embodiments, the broadcast or multicast message transmission and the actual multi-hop data transmissions may be supported by different configured bands (e.g., low-bands (e.g., frequency resource one (FR1)) for broadcast or multicast control messages (e.g., multi-hop PDCCH configuration, MCI, etc.) between the primary UE 906 and other cluster UEs. Other FRs (e.g., FR2, FR4, etcetera) may be utilized for unicast data and corresponding ACK transmissions on individual hops between cluster member UEs. In some embodiments, the broadcast or multicast transmission of control messages may utilize existing multicast or groupcast mechanisms included in NR sidelink specifications (e.g., TS 38.300 and TS 38.351). In various embodiments, different RATs may be utilized for different transmissions between UEs and/or BSs. For example, a first RAT may be utilized for control signaling and a second RAT may be used for transmitting payload data.

[0108] FIG. 10 illustrates an exemplary process diagram 1000 for adaptive radio link control (RLC) mode assignments in support of multi -hop transmissions according to some embodiments. Process diagram 1000 includes UEs 1002, 1004, 1006, 1008 and BS 1010. The intermediate UE 1008 may be the primary UE 1008. In various embodiments, RLC mode may be dynamically adjusted for different hops based on data packet characteristics and/or local channel conditions. In some embodiments, RLC mode adjustment may be performed in conjunction with or independent of other techniques described hereby. It will be appreciated that one or more components of FIG. 10 may be the same or similar to one or more other components disclosed hereby. For example, primary UE 1008 may be the same or similar to one or more of primary UE 712, primary UE 728a, primary UE 728b, primary UE 806, and primary UE 906. In another example, BS 1010 may be the same or similar to one or more of BS 704, BS 716a, BS 716b, BS 810, and BS 910. Further, aspects discussed with respect to various components in FIG. 10 may be implemented by one or more other components from one or more other embodiments without departing from the scope of this disclosure. Embodiments are not limited in this context.

[0109] In various embodiments, the adaptive RLC mode assignments may be controlled by the BS 1010 (e.g., a gNB) and/or one or more of the UEs. Referring to BS controlled adaptive RLC mode assignment, for different traffic flows with dedicated QoS requirements/classes scheduled from a source UE to a destination UE, the BS 1010 may adaptively configure RLC transparent mode (TM), RLC acknowledged mode (AM), and RLC unacknowledged mode (UM) of various UEs in the UE cluster. In some embodiments, the RLC mode may only be adaptively configured for a subset of the UEs in the UE cluster, such as just for the intermediate UEs or just for the intermediate and destination UEs. In many embodiments, the RLC mode may be determined based on inputs (e.g., provided as reporting data) such as one or more of statistical information of surrendered resources from UEs, the QoS requirement/class of the traffic (e.g., the latency, bit error rate (BER), and/or frame error rate (FER)), per hop ACK/NACK statistics, the decoder capability of each UE, and local per UE CSE In various embodiments, the statistical information of surrendered resources may include an indication of surrendered resources with respect to the assigned resources. The BS 1010 may inform the UEs of their assigned RLC mode via an RRC message, a MAC control element (CE) message, or a downlink control information (DCI) message.

[0110] In some embodiments, the adaptive RLC mode assignments may be controlled by one or more UEs in the UE cluster. For example, a UE may locally configure the RLC mode for itself and/or as requested by its previous and/or next hop neighbor UE. In some embodiments, the RLC mode may only be adaptively configured for a subset of the UEs in the UE cluster, such as just for the intermediate UEs or just for the intermediate and destination UEs. In many embodiments, the RLC mode may be determined based on inputs such as one or more of statistical information of surrendered resources from UEs, the QoS requirement/class of the traffic (e.g., the latency, bit error rate (BER), and/or frame error rate (FER)), and per hop ACK/NACK statistics. In some embodiments, a neighboring UE may request another UE to utilize a specific RLC mode. For example, a neighboring UE can request a UE to switch from RLC AM to RLC UM or switch to RLC AM from RLC TM mode. In various embodiments, a neighboring UE may signal the chosen or requested RLC mode in the RLC header. For example, a strong channel conditions may enable RLC UM because the strong channel conditions give assurance that a message will be properly received. Conversely, weak channel conditions may necessitate the use of RLC AM to ensure messages are properly received.

[0111] Referring back to process diagram 1000, in some embodiments, each of the UEs 1002, 1004, 1006, 1008 may report data for RLC mode determinations to the BS 1010 (e.g., via one or more other UEs). For example, the per hop ACK/NACK statistics, the decoder capability (e.g., performance characteristics), and local CSI for each UE may be provided to BS 1010 in reporting process 1012a for UE 1002, reporting process 1012b for UE 1004, reporting process 1012c for UE 1006, and reporting process 1012d for primary UE 1008. The BS 1010 may utilize these inputs to perform RLC mode determination 1014. The BS 1010 may then communicate the assigned the RLC modes for each UE (e.g., via primary UE 1008 and/or one or more other UEs) in RRC messages, MAC CE messages, or DCI messages. In the illustrated embodiment, the RLC mode for UE 1002 may be assigned in RLC mode assignment process 1016a, the RLC mode for UE 1004 may be assigned in RLC mode assignment process 1016b, the RLC mode for UE 1006 may be assigned in RLC mode assignment process 1016c, and the RLC mode for primary UE 1008 may be assigned in RLC mode assignment process 1016d).

[0112] As previously mentioned, in some embodiments, the RLC mode may only be assigned for a subset of UEs in the UE cluster. For example, the RLC mode may be assigned just for the intermediate UEs and the destination UE. In such an example, for a QoS indicator value of one, UE 1004 may be assigned RRC AM, UE 1006 may be assigned RRC AM, and primary UE 1008 may be assigned RRC UM. In another such example, for a QoS indicator value of two, UE 1004 may be assigned RRC AM, UE 1006 may be assigned RRC UM, and primary UE 1008 may be assigned RRC AM. In yet another such embodiment, for a QoS indicator value of three, UE 1004 may be assigned RRC TM, UE 1006 may be assigned RRC TM, and primary UE 1008 may be assigned RRC TM.

[0113] FIG. 11 illustrates an exemplary process diagram 1100 for dynamic parameter assignments in support of multi-hop transmissions according to some embodiments. Process diagram 1100 includes UEs 1102, 1104, 1106, 1108 and BS 1110. The intermediate UE 1108 may be the primary UE 1108. In various embodiments, the maximum number of retransmissions may be dynamically adjusted for different hops based on data packet characteristics and/or local channel conditions. In some embodiments, dynamic parameters assignments may be performed in conjunction with or independent of other techniques described hereby. It will be appreciated that one or more components of FIG. 11 may be the same or similar to one or more other components disclosed hereby. For example, primary UE 1108 may be the same or similar to one or more of primary UE 712, primary UE 728a, primary UE 728b, primary UE 806, and primary UE 906. In another example, BS 1110 may be the same or similar to one or more of BS 704, BS 716a, BS 716b, BS 810, and BS 910. Further, aspects discussed with respect to various components in FIG. 11 may be implemented by one or more other components from one or more other embodiments without departing from the scope of this disclosure. Embodiments are not limited in this context.

[0114] In many embodiments, the maximum number of retransmissions parameter may be dynamically adjusted at one or more UEs based on one or more of a QoS of the packet, a CSI report from the receiving UE in the multi-hop transmission chain, an accumulated latency for the multi-hop transmission, and network congestion. In various embodiments, the parameter adjustment may be controlled by one or more of an intermediate UE, a primary UE, and a BS. If the parameter adjustment is performed by primary UE 1008 and/or BS 1010, then the control messages may either be sent to the affected UEs via unicast, multicast, or broadcast messages. Further, the control messages controlling the parameter adjustment may utilize a different frequency band (e.g., low-frequency band such as FR1) than the data transmission band (e.g., high-frequency band such as FR2). The parameter adjustment may either be requested by the UE or directed by the BS.

[0115] Referring back to process diagram 1100, in some embodiments, each of the UEs 1102, 1104, 1106, 1108 may report data for maximum number of retransmission determinations to the BS 1110 (e.g., via one or more other UEs). For example, the per hop ACK/NACK statistics and local CSI for each UE may be provided to BS 1110 in reporting process 1112a for UE 1102, reporting process 1112b for UE 1104, reporting process 1112c for UE 1106, and reporting process 1112d for primary UE 1108. The BS 1110 may utilize these inputs to perform parameter assignment determination 1114. The BS 1110 may then communicate the assigned parameters for each UE (e.g., via primary UE 1108 and/or one or more other UEs) in RRC messages, MAC CE messages, or DCI messages. In the illustrated embodiment, the maximum number of retransmissions for UE 1102 may be assigned in parameter assignment process 1116a, the maximum number of retransmissions for UE 1104 may be assigned in parameter assignment process 1116b, the maximum number of retransmissions for UE 1106 may be assigned in parameter assignment process 1116c, and the maximum number of retransmissions for primary UE 1108 may be assigned in parameter assignment process 1116d.

[0116] Some embodiments may utilize multi -hop latency control with retransmissions. For example, with MCI, each UE may get an initial hop-count (equaling the maximum number of hops), which the originating UE (e.g., source UE) bounds to each packet that the UE wants to send. This hop count may be selected by the BS, such as depending on one or more of packet type (e.g., transmission control protocol (TCP), user datagram protocol (UDP), quick UDP internet connections (QUIC), etc.), real time or non-real time traffic, QoS, number of hops, and reliability requirements. After each hop to the next UE, the hop count may be decremented by one. The hop count may be decremented independent of whether the preceding transmission is an initial transmission or a retransmission. When the hop count reaches zero, the packet may be discarded at the current UE. When the final UE (e.g., destination UE) is reached, the destination UE may acknowledge reception and report the remaining hop count of the packet, such as to the source UE. For example, the remaining hop count may be reported to the BS (e.g., via one or more other UEs). Additionally, or alternatively, the remaining hop counts may be utilized for further packets or surrendered to the BS. In some embodiments, instead of the final acknowledgement being sent to the source UE carrying the remaining hop count, each UE may periodically report resource surrender indications to the primary UE. In various embodiments, the resource surrender indication may include one or more of accumulated/average remaining hop count for all packets. In various embodiments, the hop count may be piggybacked within a mesh network (e.g., UE cluster) without additional header overhead, such as via time-to-live (IPv4) or hop limit (IPv6).

[0117] Various embodiments described hereby may include one or more of the following features. In some embodiments, a primary UE (e.g., network-controlled relay UE) supporting URLLC transmissions may request resources from a gNB for a multi-hop transmission, with possible retransmissions. In various embodiments, the Primary UE may allocate resources to the source UE and intermediate UEs for initial transmission and configured number of re-transmissions, which may collectively be referred to as transmissions. In several embodiments, the max number of retransmissions may be different per hop. In many embodiments, the transmitting UE on each hop may continue retransmissions on the granted resources until an ACK is received or the max number of retransmission attempts is reached. In various embodiments, an intermediate UE may start transmitting on the next hop when it successfully decodes the transmission on the previous hop, even if the max number of re-transmissions is not reached. In some embodiments, the intermediate UE may send an ACK when the transmission on the previous hop is successfully decoded. In many embodiments, the primary UE may surrender any unused resources when the transmission is correctly received by the destination UE. In several embodiments, an intermediate UE may transmit dummy/null data on unused resources for autonomous transmissions, if it is not able to successfully decode the transmission on the previous hop by the start of transmission resources on the next hop. In various embodiments, the RLC Mode for transmission on an intermediate hop may be dynamically changed to satisfy the latency and reliability requirement due to changing channel conditions and statistical information (i.e., surrendered retransmission resources, ACK/NACK, etcetera) in the multi-hop links. In many embodiments, a UE may be configured with resources for receiving a data packet from a source device and transmitting the data packet to a destination device. In many such embodiments, the source device may be a first neighbor UE or gNB/BS and the destination device may be a second neighbor UE or gNB/BS. In several embodiments, the configuration of UEs may include one or more of: resources for multiple transmission attempts from the source device to the current UE and from the current UE to the destination device; an indication for RLC transmission modes (e.g., RLC AM, RLC UM, or RLC TM) for source to current and current to destination device links; resources for ACK transmission after each retransmission attempt on both source to current and current to destination device links; resources to send resource surrender indication to the gNB/BS; and a pattern (e.g., predetermined bit sequence) for dummy/null data (e.g., non-payload data). In many embodiments, the UE may wait until it correctly decodes the data packet from the source device before starting packet transmission to the destination device on one of the granted resources. In many such embodiments, the resources meant for transmission to the destination device that arrive before the UE is able to correctly decode the incoming data packet from the source device may be used to transmit dummy/null data packet (e.g., non-payload data). In some embodiments, this may be a pre-configured bit sequence that is robustly encoded to ensure correct reception (e.g., prevent soft-combining). In some embodiments, the current UE may monitor for ACK transmission from the destination device on the indicated resources. In some such embodiments, if an ACK is received before the configured number of retransmission attempts are completed then the UE may stop further retransmissions on the previously granted resources and surrenders the resources to the gNB/BS, such as by sending a resource surrender indication on the indicated resources.

[0118] FIG. 12 illustrates a logic flow 1200 of an exemplary technique associated with multi-hop transmissions according to some embodiments. Aspects of logic flow 1200 may relate to various embodiments described hereby. Logic flow 1200 may begin at block 1202. Block 1202 may include identifying transmission resources comprising a plurality of slots allocated for transmission of payload data in at least one hop of a multi-hop transmission from a source UE to a destination UE via one or more intermediate UEs, wherein the one or more intermediate UEs comprise at least one primary UE communicatively coupled with a base station (BS). For example, intermediate UE 804 may identify transmission resources comprising slots 820a, 820b, 820c based on an MCI message received as part of resource acquisition process 812e. [0119] At block 1204, it may be determined that payload data is unavailable for transmission in a first slot of the plurality of slots. For example, payload data may be unavailable for transmission by primary UE 806 in slot 828a because the payload data has not been received from intermediate UE 804 in the prior hop of the multi-hop transmission. Continuing to block 1206, non-payload data may be transmitted in the first slot of the plurality of slots in response to the payload data being unavailable for transmission in the first slot. For example, non-payload data transmission 830 may occur in slot 828a in response to the payload data being unavailable for transmission. In many embodiments, the non-payload data may comprise a predetermined bit sequence configured to prevent the non-payload data from being soft-combined with the payload data once the payload data is received.

[0120] Proceeding to block 1208, the payload data may be determined to be available for transmission in a second slot of the plurality of slots. For example, primary UE 806 may determine the payload data is ready from transmission based on successfully receiving and decoding the payload data from payload data transmission 822b and/or preparing the payload data for inclusion in payload data transmission 834. At block 1210, the payload data may be transmitted in the second slot of the plurality of slots in response to the payload data being available for transmission in the second slot. For example, the payload data may be sent in payload data transmission 834 during 828b in response to the payload data being received and available for transmission from intermediate UE 804 in payload data transmission 822b.

[0121] FIG. 13 illustrates a logic flow 1300 of an exemplary technique associated with resource assignment according to some embodiments. Aspects of logic flow 1300 may relate to various embodiments described hereby. Logic flow 1300 may begin at block 1302. Block 1302 may include receiving a resource request associated with a multi-hop transmission by a UE cluster. Further, the UE cluster may comprise a source UE, a destination UE, and one or more intermediate UEs and the multihop transmission to send payload data from the source UE to the destination UE via the one or more intermediate UEs, wherein the one or more intermediate UEs comprise at least one primary UE. For example, BS 810 may receive a resource request for a multi-hop transmission associated with a UE cluster including source UE 802, intermediate UEs 804, 806, and destination UE 808 with intermediate UE 806 comprising a primary UE. The multi-hop transmission may be for sending payload data from the source UE 802 to the destination UE 808 via the intermediate UEs 804, 806. In some embodiments, the resource request may be included in a mesh resource request message received by the BS 810 as part of resource acquisition process 812b.

[0122] At block 1304, a set of resources for the multi-hop transmission by the UE cluster may be determined. Further, the set of resources may include resources for initial transmissions and a maximum number of retransmissions on each hop of the multi-hop transmission. For example, BS 810 may determine a set of resources for initial transmission and a maximum number of retransmission that includes slots 814 for a first hop between source UE 802 and intermediate UE 804, slots 820 for a second hop between intermediate UE 804 and primary UE 806, and slots 828 for a third hop between primary UE 806 and destination UE 808. Proceeding to block 1306, a resource response comprising the set of resources determined for the multi-hop transmission may be transmitted to the at least one primary UE. Continuing with the previous example, BS 810 may transmit a resource response comprising the set of resources determined for the multi-hop transmission to primary UE 806 as part of resource acquisition process 812c. In several embodiments, the resource response may comprise a mesh resource response message.

[0123] At block 1308, an indication of a set of surrendered resources comprising a subset of the set of resource determined for the multi-hop transmission may be received. Continuing again with the previous example, BS 810 may receive an indication of a set of surrendered resources comprising slot 828d as part of resource surrender process 838b. In some embodiments, the indication of the set of surrendered resources may be included in a mesh resource indication message. Proceeding to block 1310, at least a portion of the set of surrendered resources may be reassigned to a transmission separate from the multi-hop transmission. Continuing again with the previous example, BS 810 may reassign slot 828d to a transmission separate from the multi-hop transmission, such as another multihop transmission.

[0124] Portions of what was described above may be implemented with logic circuitry such as a dedicated logic circuit or with a microcontroller or other form of processing core that executes program code instructions. Thus, processes taught by the discussion above may be performed with program code such as machine-executable instructions that cause a machine that executes these instructions to perform certain functions. In this context, a “machine” may be a machine that converts intermediate form (or “abstract”) instructions into processor specific instructions (e.g., an abstract execution environment such as a “virtual machine” (e.g., a Java Virtual Machine), an interpreter, a Common Language Runtime, a high-level language virtual machine, etc.), and/or, electronic circuitry disposed on a semiconductor chip (e.g., “logic circuitry” implemented with transistors) designed to execute instructions such as a general-purpose processor and/or a special-purpose processor. Processes taught by the discussion above may also be performed by (in the alternative to a machine or in combination with a machine) electronic circuitry designed to perform the processes (or a portion thereof) without the execution of program code.

[0125] The present disclosure also relates to an apparatus for performing the operations described herein. This apparatus may be specially constructed for the required purpose, or it may comprise a general-purpose computer selectively activated or reconfigured by a computer program stored in the computer. Such a computer program may be stored in a computer readable storage medium, such as, but is not limited to, any type of disk including floppy disks, optical disks, CD-ROMs, and magnetic- optical disks, read-only memories (ROMs), RAMs, EPROMs, EEPROMs, magnetic or optical cards, or any type of media suitable for storing electronic instructions, and each coupled to a computer system bus. [0126] A machine readable medium includes any mechanism for storing or transmitting information in a form readable by a machine (e.g., a computer). For example, a machine readable medium includes read only memory (“ROM”); random access memory (“RAM”); magnetic disk storage media; optical storage media; flash memory devices; etcetera.

[0127] An article of manufacture may be used to store program code. An article of manufacture that stores program code may be embodied as, but is not limited to, one or more memories (e.g., one or more flash memories, random access memories (static, dynamic or other)), optical disks, CD-ROMs, DVD ROMs, EPROMs, EEPROMs, magnetic or optical cards or other type of machine-readable media suitable for storing electronic instructions. Program code may also be downloaded from a remote computer (e.g., a server) to a requesting computer (e.g., a client) by way of data signals embodied in a propagation medium (e.g., via a communication link (e.g., a network connection)).

[0128] There are a number of example embodiments described herein.

[0129] Example 1 is a method for wireless communication by a user equipment (UE), the method comprising: identifying transmission resources comprising a plurality of slots allocated for transmission of payload data in at least one hop of a multi-hop transmission from a source UE to a destination UE via one or more intermediate UEs, wherein the one or more intermediate UEs comprise at least one primary UE communicatively coupled with a base station (BS); determining the payload data is unavailable for transmission in a first slot of the plurality of slots; transmitting non-payload data in the first slot of the plurality of slots in response to the payload data being unavailable for transmission in the first slot; determining the payload data is available for transmission in a second slot of the plurality of slots; and transmitting the payload data in the second slot of the plurality of slots in response to the payload data being available for transmission in the second slot.

[0130] Example 2 is the method of Example 1 that may optionally include failing to receive an acknowledgement in response to transmission of the payload data in the second slot prior to a third slot of the plurality of slots; and retransmitting the payload data in the third slot of the plurality of slots in response to failure to receive the acknowledgement.

[0131] Example 3 is the method of Example 1 that may optionally include receiving an acknowledgement in response to transmission of the payload data in the second slot prior to a third slot of the plurality of slots; and surrendering the third slot of the plurality of slots in response to receiving the acknowledgement prior to the third slot.

[0132] Example 4 is the method of Example 3 that may optionally include transmitting a mesh control information (MCI) message to the primary UE to surrender the third slot, wherein the MCI message includes an indication of the third slot.

[0133] Example 5 is the method of Example 4 that may optionally include that the primary UE releases the third slot to a base station (BS) via a mesh resource indication message. [0134] Example 6 is the method of Example 1 that may optionally include that the non-payload data comprises a predetermined bit sequence configured to prevent soft-combining of the non-payload data and the payload data.

[0135] Example 7 is the method of Example 1 that may optionally include that the non-payload data comprises null data.

[0136] Example 8 is the method of Example 1 that may optionally include determining a number of retransmission attempts in the multi-hop transmission based on a quality of service (QoS) requirement for the multi-hop transmission.

[0137] Example 9 is the method of Example 1 that may optionally include that the transmission resources comprise the plurality of slots allocated for transmission of the payload data in the at least one hop of the multi-hop transmission are identified based on a mesh control information (MCI) message.

[0138] Example 10 is the method of Example 9 that may optionally include monitoring resources identified in a multi-hop physical downlink control channel (PDCCH) configuration message for the MCI message.

[0139] Example 11 is the method of Example 9 that may optionally include determining a maximum number of retransmission attempts for the payload data based on the MCI message.

[0140] Example 12 is the method of Example 11 that may optionally include adjusting the maximum number of retransmission attempts for the payload data based on a channel state information (CSI) report generated by an intermediate UE of the one or more intermediate UEs, wherein the intermediate UE receives the payload data in a first hop of the multi-hop transmission and relays the payload data to another UE in a second hop of the multi-hop transmission.

[0141] Example 13 is the method of Example 1 that may optionally include that the one or more intermediate UEs comprise a first intermediate UE and a second intermediate UE, the BS comprises a first BS and a second BS, the first intermediate UE comprises a first primary UE communicatively coupled with the first BS, and the second intermediate UE comprises a second primary UE communicatively coupled with the second BS, and wherein the source UE and the first intermediate UE are included in a first UE cluster and the destination UE and the second intermediate UE are included in a second UE cluster.

[0142] Example 14 is the method of Example 1 that may optionally include switching from a first radio link control (RLC) mode to a second RLC mode in response to an indication received in a message from another UE.

[0143] Example 15 is the method of Example 14 that may optionally include that the indication is received in an RLC header of the message. [0144] Example 16 is the method of Example 14 that may optionally include that the first RLC mode includes an unacknowledged mode (UM) and the second RLC mode includes an acknowledged mode (AM).

[0145] Example 17 is the method of Example 1 that may optionally include switching from a first radio link control (RLC) mode to a second RLC mode in response to an indication received in a message from the BS via a primary UE of the at least one primary UE.

[0146] Example 18 is the method of Example 17 that may optionally include that the first RLC mode includes a transparent mode (TM) and the second RLC mode includes an acknowledged mode (AM). [0147] Example 19 is the method of Example 1 that may optionally include receiving the payload data and a maximum number of remaining hops from the source UE; decrementing the maximum number of remaining hops; and transmitting the payload data and the decremented maximum number of remaining hops in the second slot.

[0148] Example 20 is the method of Example 1 that may optionally include receiving the payload data and a maximum number of remaining hops from the source UE; decrementing the maximum number of remaining hops; determining the decremented maximum number of remaining hops is zero; and discarding the payload data in response to determining the decremented maximum number of remaining hops is zero.

[0149] Example 21 is a user equipment (UE) comprising one or more processors configured to perform the method of any of Examples 1 to 20.

[0150] Example 22 is a non-transitory machine-readable medium having executable instructions to cause one or more processing units to perform the method of any of Examples 1 to 20.

[0151] Example 23 is a method for wireless communication resource assignment by a base station (BS), the method comprising: receiving a resource request associated with a multi-hop transmission by a UE cluster, the UE cluster comprising a source UE, a destination UE, and one or more intermediate UEs, and the multi-hop transmission to send payload data from the source UE to the destination UE via the one or more intermediate UEs, wherein the one or more intermediate UEs comprise at least one primary UE; determining a set of resources for the multi-hop transmission by the UE cluster, the set of resources including resources for initial transmissions and a maximum number of retransmissions on each hop of the multi-hop transmission; transmitting a resource response to the at least one primary UE comprising the set of resources determined for the multi-hop transmission; receiving an indication of a set of surrendered resources, the set of surrendered resources comprising a subset of the set of resources determined for the multi-hop transmission by the UE cluster; and reassigning at least a portion of the set of surrendered resources to a transmission separate from the multi-hop transmission.

[0152] Example 24 is the method of Example 23 that may optionally include that the resource request is received from the at least one primary UE. [0153] Example 25 is the method of Example 23 that may optionally include that the resource request comprises a mesh resource request message.

[0154] Example 26 is the method of Example 23 that may optionally include that the resource response comprises a mesh resource response message.

[0155] Example 27 is the method of Example 23 that may optionally include that the indication of the set of surrendered resources comprises a mesh resource indication message.

[0156] Example 28 is the method of Example 23 that may optionally include receiving reporting data for at least one UE in the UE cluster, the reporting data including one or more of statistical information of surrendered resources, a quality of service (QoS) requirement, latency, bit error rate, frame error rate, per hop acknowledgement and negative acknowledgement statistics, decoder capability, and channel state information (CSI); determining a radio link control (RLC) mode for the at least one UE based on the reporting data; and causing the at least one UE to operate in the RLC mode determined for the at least one UE.

[0157] Example 29 is the method of Example 28 that may optionally include causing the at least one UE to operate in the RLC mode via one or more of a radio resource control (RRC) message, a media access control (MAC) control element (CE) message, and a downlink control information (DCI) message.

[0158] Example 30 is the method of Example 23 that may optionally include receiving reporting data for at least one UE in the UE cluster, the reporting data including one or more of a quality of service (QoS) requirement, channel state information (CSI), accumulated latency for the multi-hop transmission, and network congestion; determining an updated maximum number of retransmissions for the at least one UE based on the reporting data; and causing the at least one UE to operate according to the updated maximum number of retransmissions.

[0159] Example 31 is the method of Example 30 that may optionally include causing the at least one UE to operate according to the updated maximum number of retransmissions via a unicast message, a multicast message, and a broadcast message.

[0160] Example 32 is the method of Example 30 that may optionally include that the maximum number of retransmissions for the at least one UE is determined in response to a request received from the at least one UE.

[0161] Example 33 is a base station (BS) comprising one or more processors configured to perform the method of any of Examples 23 to 32.

[0162] Example 34 is a non-transitory machine-readable medium having executable instructions to cause one or more processing units to perform the method of any of Examples 23 to 32.

[0163] The preceding detailed descriptions are presented in terms of algorithms and symbolic representations of operations on data bits within a computer memory. These algorithmic descriptions and representations are the tools used by those skilled in the data processing arts to most effectively convey the substance of their work to others skilled in the art. An algorithm is here, and generally, conceived to be a self-consistent sequence of operations leading to a desired result. The operations are those requiring physical manipulations of physical quantities. Usually, though not necessarily, these quantities take the form of electrical or magnetic signals capable of being stored, transferred, combined, compared, and otherwise manipulated. It has proven convenient at times, principally for reasons of common usage, to refer to these signals as bits, values, elements, symbols, characters, terms, numbers, or the like.

[0164] It should be kept in mind, however, that all of these and similar terms are to be associated with the appropriate physical quantities and are merely convenient labels applied to these quantities. Unless specifically stated otherwise as apparent from the above discussion, it is appreciated that throughout the description, discussions utilizing terms such as “selecting,” “determining,” “receiving,” “forming,” “grouping,” “aggregating,” “generating,” “removing,” or the like, refer to the action and processes of a computer system, or similar electronic computing device, that manipulates and transforms data represented as physical (electronic) quantities within the computer system's registers and memories into other data similarly represented as physical quantities within the computer system memories or registers or other such information storage, transmission or display devices.

[0165] The processes and displays presented herein are not inherently related to any particular computer or other apparatus. Various general-purpose systems may be used with programs in accordance with the teachings herein, or it may prove convenient to construct a more specialized apparatus to perform the operations described. The required structure for a variety of these systems will be evident from the description below. In addition, the present disclosure is not described with reference to any particular programming language. It will be appreciated that a variety of programming languages may be used to implement the teachings of the disclosure as described herein.

[0166] It is well understood that the use of personally identifiable information should follow privacy policies and practices that are generally recognized as meeting or exceeding industry or governmental requirements for maintaining the privacy of users. In particular, personally identifiable information data should be managed and handled so as to minimize risks of unintentional or unauthorized access or use, and the nature of authorized use should be clearly indicated to users.

[0167] The foregoing discussion merely describes some exemplary embodiments of the present disclosure. One skilled in the art will readily recognize from such discussion, the accompanying drawings and the claims that various modifications can be made without departing from the spirit and scope of the disclosure.

Claims

1. A method for wireless communication by a user equipment (UE), the method comprising: identifying transmission resources comprising a plurality of slots allocated for transmission of payload data in at least one hop of a multi-hop transmission from a source UE to a destination UE via one or more intermediate UEs, wherein the one or more intermediate UEs comprise at least one primary UE communicatively coupled with a base station (BS); determining the payload data is unavailable for transmission in a first slot of the plurality of slots; transmitting non-payload data in the first slot of the plurality of slots in response to the payload data being unavailable for transmission in the first slot; determining the payload data is available for transmission in a second slot of the plurality of slots; and transmitting the payload data in the second slot of the plurality of slots in response to the payload data being available for transmission in the second slot.

2. The method of claim 1, further comprising: failing to receive an acknowledgement in response to transmission of the payload data in the second slot prior to a third slot of the plurality of slots; and retransmitting the payload data in the third slot of the plurality of slots in response to failure to receive the acknowledgement.

3. The method of claim 1, further comprising: receiving an acknowledgement in response to transmission of the payload data in the second slot prior to a third slot of the plurality of slots; and surrendering the third slot of the plurality of slots in response to receiving the acknowledgement prior to the third slot.

4. The method of claim 3, further comprising transmitting a mesh control information (MCI) message to the primary UE to surrender the third slot, wherein the MCI message includes an indication of the third slot.

5. The method of claim 4, wherein the primary UE releases the third slot to a base station (BS) via a mesh resource indication message.

6. The method of claim 1, wherein the non-payload data comprises a predetermined bit sequence configured to prevent soft-combining of the non-payload data and the payload data.

7. The method of claim 1, wherein the non-payload data comprises null data.

8. The method of claim 1, further comprising determining a number of retransmission attempts in the multi-hop transmission based on a quality of service (QoS) requirement for the multi-hop transmission.

9. The method of claim 1, wherein the transmission resources comprise the plurality of slots allocated for transmission of the payload data in the at least one hop of the multi-hop transmission are identified based on a mesh control information (MCI) message.

10. The method of claim 9, further comprising monitoring resources identified in a multi-hop physical downlink control channel (PDCCH) configuration message for the MCI message.

11. The method of claim 9, further comprising determining a maximum number of retransmission attempts for the payload data based on the MCI message.

12. The method of claim 11, further comprising adjusting the maximum number of retransmission attempts for the payload data based on a channel state information (CSI) report generated by an intermediate UE of the one or more intermediate UEs, wherein the intermediate UE receives the payload data in a first hop of the multi-hop transmission and relays the payload data to another UE in a second hop of the multi-hop transmission.

13. The method of claim 1, wherein the one or more intermediate UEs comprise a first intermediate UE and a second intermediate UE, the BS comprises a first BS and a second BS, the first intermediate UE comprises a first primary UE communicatively coupled with the first BS, and the second intermediate UE comprises a second primary UE communicatively coupled with the second BS, and wherein the source UE and the first intermediate UE are included in a first UE cluster and the destination UE and the second intermediate UE are included in a second UE cluster.

14. The method of claim 1, further comprising switching from a first radio link control (RLC) mode to a second RLC mode in response to an indication received in a message from another UE.

15. The method of claim 14, wherein the indication is received in an RLC header of the message.

16. The method of claim 14, wherein the first RLC mode includes an unacknowledged mode (UM) and the second RLC mode includes an acknowledged mode (AM).

17. The method of claim 1, further comprising switching from a first radio link control (RLC) mode to a second RLC mode in response to an indication received in a message from the BS via a primary UE of the at least one primary UE.

18. The method of claim 17, wherein the first RLC mode includes a transparent mode (TM) and the second RLC mode includes an acknowledged mode (AM).

19. The method of claim 1, further comprising: receiving the payload data and a maximum number of remaining hops from the source UE; decrementing the maximum number of remaining hops; and transmitting the payload data and the decremented maximum number of remaining hops in the second slot.

20. The method of claim 1, further comprising: receiving the payload data and a maximum number of remaining hops from the source UE; decrementing the maximum number of remaining hops; determining the decremented maximum number of remaining hops is zero; and discarding the payload data in response to determining the decremented maximum number of remaining hops is zero.

21. A user equipment (UE) comprising one or more processors configured to perform the method of any of claims 1 to 20.

22. A non-transitory machine -readable medium having executable instructions to cause one or more processing units to perform the method of any of claims 1 to 20.

23. A method for wireless communication resource assignment by a base station (BS), the method comprising: receiving a resource request associated with a multi-hop transmission by a UE cluster, the UE cluster comprising a source UE, a destination UE, and one or more intermediate UEs, and the multi-hop transmission to send payload data from the source UE to the destination UE via the one or more intermediate UEs, wherein the one or more intermediate UEs comprise at least one primary UE; determining a set of resources for the multi-hop transmission by the UE cluster, the set of resources including resources for initial transmissions and a maximum number of retransmissions on each hop of the multi-hop transmission; transmitting a resource response to the at least one primary UE comprising the set of resources determined for the multi -hop transmission; receiving an indication of a set of surrendered resources, the set of surrendered resources comprising a subset of the set of resources determined for the multi-hop transmission by the UE cluster; and reassigning at least a portion of the set of surrendered resources to a transmission separate from the multi-hop transmission.

24. The method of claim 23, wherein the resource request is received from the at least one primary UE.

25. The method of claim 23, wherein the resource request comprises a mesh resource request message.

26. The method of claim 23, wherein the resource response comprises a mesh resource response message.

27. The method of claim 23, wherein the indication of the set of surrendered resources comprises a mesh resource indication message.

28. The method of claim 23, further comprising: receiving reporting data for at least one UE in the UE cluster, the reporting data including one or more of statistical information of surrendered resources, a quality of service (QoS) requirement, latency, bit error rate, frame error rate, per hop acknowledgement and negative acknowledgement statistics, decoder capability, and channel state information (CSI); determining a radio link control (RLC) mode for the at least one UE based on the reporting data; and causing the at least one UE to operate in the RLC mode determined for the at least one UE.

29. The method of claim 28, further comprising causing the at least one UE to operate in the RLC mode via one or more of a radio resource control (RRC) message, a media access control (MAC) control element (CE) message, and a downlink control information (DCI) message.

30. The method of claim 23, further comprising: receiving reporting data for at least one UE in the UE cluster, the reporting data including one or more of a quality of service (QoS) requirement, channel state information (CSI), accumulated latency for the multi-hop transmission, and network congestion; determining an updated maximum number of retransmissions for the at least one UE based on the reporting data; and causing the at least one UE to operate according to the updated maximum number of retransmissions.

31. The method of claim 30, further comprising causing the at least one UE to operate according to the updated maximum number of retransmissions via a unicast message, a multicast message, and a broadcast message.

32. The method of claim 30, wherein the maximum number of retransmissions for the at least one UE is determined in response to a request received from the at least one UE.

33. A base station (BS) comprising one or more processors configured to perform the method of any of claims 23 to 32.

34. A non-transitory machine -readable medium having executable instructions to cause one or more processing units to perform the method of any of claims 23 to 32.