Reporting and scheduling in an integrated access backhaul network

Wireless communications systems and methods related to communicating in an integrated access backhaul (IAB) network are provided. A first wireless communication device transmits to a second wireless device during a first one of a plurality of slots; and receives a second transmission from the second wireless device during a second one of the plurality of slots. The second transmission includes link quality information about the first transmission and scheduling information for a third transmission between the first and second wireless devices.

TECHNICAL FIELD

This application relates to wireless communication systems, and more particularly to communicating access data and backhaul data over wireless links in an integrated access backhaul (IAB) network. Embodiments enable and provide solutions and techniques for communication between wireless communication devices (e.g., base stations and user equipment devices (UEs)) in an IAB network.

INTRODUCTION

To meet the growing demands for expanded mobile broadband connectivity, wireless communication technologies are advancing from the LTE technology to a fifth generation (5G) new radio (NR) technology. 5G NR may provide for access traffic and backhaul traffic at gigabit-level throughput. Access traffic refers to traffic between an access node (e.g., a base station) and a UE. Backhaul traffic refers to traffic between access nodes or traffic between an access node and a core network.

BRIEF SUMMARY OF SOME EXAMPLES

For example, in an aspect of the disclosure, a method of wireless communication may include transmitting, by the first wireless communication device, a first transmission to the second wireless device during a first one of the plurality of slots; and receiving, by the first wireless communication device, a second transmission from the second wireless device during a second one of the plurality of slots, the second transmission including link quality information about the first transmission and scheduling a third transmission between the first and second wireless devices.

In some aspects, a method of wireless communication may include transmitting, by the first wireless communication device, a first transmission to the second wireless device during a first one of the plurality of slots; and receiving, by the first wireless communication device, a second transmission from the second wireless device during a second one of the plurality of slots, the second transmission including link quality information about the first transmission and scheduling a third transmission between the first and second wireless devices, wherein the third transmission is transmitted by the second node and received by the first node.

In another aspect, a method of wireless communication may include transmitting, by the first wireless communication device, a first transmission to the second wireless device during a first one of the plurality of slots; and receiving, by the first wireless communication device, a second transmission from the second wireless device during a second one of the plurality of slots, the second transmission including link quality information about the first transmission and scheduling a third transmission between the first and second wireless devices, wherein the third transmission is transmitted by the first node and received by the second node.

In the foregoing aspects, each of the plurality of slots may include a control channel and a data channel, and the link quality information is transmitted in a control channel of the second slot or in a data channel of the second slot. In another aspect each of the plurality of slots includes a control channel and a data channel, and the ACK/NACK is transmitted in a control channel of the second slot or in a data channel of the second slot.

In some aspects a method of wireless communication may include transmitting, by the first wireless communication device, a first transmission to the second wireless device during a first one of the plurality of slots; and receiving, by the first wireless communication device, a second transmission from the second wireless device during a second one of the plurality of slots, the second transmission including link quality information about the first transmission and scheduling a third transmission between the first and second wireless devices, wherein the link quality information about the first transmission includes a least one or more combinations of CQI, reference signal received power (RSRP), signal to noise ratio (SNR), reference signal received quality (RSRQ), RSSI, beam index, beam coherence time, and beam quality.

In some aspects a method of wireless communication may include transmitting, by the first wireless communication device, a first transmission to the second wireless device during a first one of the plurality of slots; and receiving, by the first wireless communication device, a second transmission from the second wireless device during a second one of the plurality of slots, the second transmission including link quality information about the first transmission and scheduling a third transmission between the first and second wireless devices, wherein the second transmission includes an ACK/NACK for data transmitted during the first transmission.

In other aspects, a method of wireless communication may include transmitting, by the first wireless communication device, a first transmission to the second wireless device during a first one of the plurality of slots; and receiving, by the first wireless communication device, a second transmission from the second wireless device during a second one of the plurality of slots, the second transmission including link quality information about the first transmission and scheduling a third transmission between the first and second wireless devices, wherein the second transmission includes a scheduling request (SR) for the first device to send a fourth transmission to the second device. The SR may be transmitted in a control channel or in a data channel.

In other aspects, user equipment for wireless communications may include a radio transceiver; a processor; and a memory; wherein the processor is in electrical communication with the transceiver and the memory; and wherein the memory is configured with instructions to cause the processor to implement any of the methods of the preceding aspects.

DETAILED DESCRIPTION

The present disclosure describes mechanisms for communicating in an IAB network. An IAB network may include a combination of wireless access links between BSs and UEs and wireless backhaul links between the BSs. The IAB network may employ a multi-hop topology (e.g., a spanning tree) for transporting access traffic and backhaul traffic. One of the BSs may be configured with an optical fiber connection in communication with a core network, where the BS may function as an anchoring node (e.g., a root node) to transport backhaul traffic between the core network and the IAB network. The other BSs may be referred to as relay nodes in the network. Each BS may have one or more parent nodes, which may include other BSs, and/or one or more child nodes, which may include other BSs and/or UEs. The UEs may function as child nodes. In some embodiments, UEs may also function as relay nodes. The parent nodes may function as access nodes to the child nodes and may be referred to as access functionality (ACF)-nodes. The child nodes may function as UEs to the parent nodes and may be referred to as UE functionality (UEF)-nodes. Thus, a BS may function as an ACF-node when communicating with a child node and may function as a UEF-node when communicating with a parent node. The disclosed embodiments provide efficient mechanisms for communication between nodes in an IAB network. A pair of nodes for which one node is in the path of communication between the other node and the core network may be referred to as having a parent-child relationship.

In an embodiment, a method of wireless communication may include transmitting, by the first wireless communication device, a first transmission to the second wireless device during a first one of the plurality of slots; and receiving, by the first wireless communication device, a second transmission from the second wireless device during a second one of the plurality of slots, the second transmission including link quality information about the first transmission and scheduling a third transmission between the first and second wireless devices.

In another embodiment, a method of wireless communication may include transmitting, by the first wireless communication device, a first transmission to the second wireless device during a first one of the plurality of slots; and receiving, by the first wireless communication device, a second transmission from the second wireless device during a second one of the plurality of slots, the second transmission including link quality information about the first transmission and scheduling a third transmission between the first and second wireless devices, wherein the third transmission is transmitted by the second node and received by the first node.

In another embodiment, a method of wireless communication may include transmitting, by the first wireless communication device, a first transmission to the second wireless device during a a first one of the plurality of slots; and receiving, by the first wireless communication device, a second transmission from the second wireless device during a second one of the plurality of slots, the second transmission including link quality information about the first transmission and scheduling a third transmission between the first and second wireless devices, wherein the third transmission is transmitted by the first node and received by the second node.

In the foregoing embodiment, each of the plurality of slots may include a control channel and a data channel, and the link quality information is transmitted in a control channel of the second slot or in a data channel of the second slot. In another aspect each of the plurality of slots includes a control channel and a data channel, and the ACK/NACK is transmitted in a control channel of the second slot or in a data channel of the second slot.

In some embodiments, a method of wireless communication may include transmitting, by the first wireless communication device, a first transmission to the second wireless device during a first one of the plurality of slots; and receiving, by the first wireless communication device, a second transmission from the second wireless device during a second one of the plurality of slots, the second transmission including link quality information about the first transmission and scheduling a third transmission between the first and second wireless devices, wherein the link quality information about the first transmission includes a least one or more combinations of CQI, reference signal received power (RSRP), signal to noise ratio (SNR), reference signal received quality (RSRQ), RSSI, beam index, beam coherence time, and beam quality.

In an embodiment, a method of wireless communication may include transmitting, by the first wireless communication device, a first transmission to the second wireless device during a first one of the plurality of slots; and receiving, by the first wireless communication device, a second transmission from the second wireless device during a second one of the plurality of slots, the second transmission including link quality information about the first transmission and scheduling a third transmission between the first and second wireless devices, wherein the second transmission includes an ACK/NACK for data transmitted during the first transmission.

In another embodiment, a method of wireless communication may include transmitting, by the first wireless communication device, a first transmission to the second wireless device during a first one of the plurality of slots; and receiving, by the first wireless communication device, a second transmission from the second wireless device during a second one of the plurality of slots, the second transmission including link quality information about the first transmission and scheduling a third transmission between the first and second wireless devices, wherein the second transmission includes a scheduling request (SR) for the first device to send a fourth transmission to the second device. The SR may be transmitted in a control channel or in a data channel.

In some embodiments, user equipment for wireless communications may include a radio transceiver; a processor; and a memory; wherein the processor is in electrical communication with the transceiver and the memory; and wherein the memory is configured with instructions to cause the processor to implement any of the methods of the preceding aspects.

The forgoing aspects of the present application can provide several benefits. For example, routing data through sidelinks may reduce the number of hops needed to get data to its destination, thereby reducing latency and improving reliability. Using sidelink may also improve overall network capacity by reducing the amount of traffic in uplink or downlink transmissions.

FIG. 1illustrates a wireless communication network100including a plurality of BSs105, a plurality of UEs115, and a core network130. The network100may be an LTE network, an LTE-A network, a millimeter wave (mmW) network, a new radio (NR) network, a 5G network, or any other successor network to LTE.

The BSs105may wirelessly communicate with the UEs115via one or more BS antennas. Each BS105may provide communication coverage for a respective geographic coverage area110. In 3GPP, the term “cell” can refer to this geographic coverage area of a BS and/or a BS subsystem serving the coverage area, depending on the context in which the term is used. In the example shown inFIG. 1, the BSs105a,105b,105c,105d, and105eare examples of macro BSs for the coverage areas110a,110b,110c,110d, and110e, respectively.

The BSs105may communicate with the core network130and with one another via optical fiber links134. The core network130may provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. At least some of the BSs105(e.g., which may be an example of an evolved NodeB (eNB), a next generation NodeB (gNB), or an access node controller (ANC)) may interface with the core network130through the backhaul links134(e.g., S1, S2, etc.) and may perform radio configuration and scheduling for communication with the UEs115. In various examples, the BSs105may communicate, either directly or indirectly (e.g., through core network130), with each other over the backhaul links134(e.g., X1, X2, etc.).

Each BS105may also communicate with other UEs115through a number of other BSs105, where the BS105may be an example of a smart radio head. In alternative configurations, various functions of each BS105may be distributed across various BSs105(e.g., radio heads and access network controllers) or consolidated into a single BS105.

FIG. 2illustrates an IAB network200according to embodiments of the present disclosure. The network200is substantially similar to the network100in many respects. For example, the BSs105communicates with the UEs115over the wireless access links125. However, in the network200, only some BSs (e.g., the BS105c) are connected to the core network by high capacity link, such as optical fiber backhaul link134. Other BSs105a,105b,105d, and105ewirelessly communicate with each other and with the BS105cover wireless backhaul links234. The BS105cconnected to the optical fiber backhaul link134may function as an anchor for the other BSs105a,105b,105d, and105eto communicate the core network130, as described in greater detail herein. The wireless access links125and the wireless backhaul links234may share resources for communications in the network200. The network200may also be referred to as a self-backhauling network. The network200can improve wireless link capacity, reduce latency, and reduce deployment cost.

In an embodiment, network200may use millimeter wave (mmWav) frequency bands for communications. In such a network, some of BSs105a,105b,105d, and105emay communicate with each other and with BS105cusing narrow directional beams for wireless links234. The BSs105may also communicate with the UEs115using narrow directional beams for wireless links125. The directional beams for links234may be substantially like the directional beams for links125. For example, the BSs105may use analog beamforming and/or digital beamforming to form the directional beams for transmission and/or reception. Similarly, UEs115may use analog beamforming and/or digital beamforming to form the directional beams for transmission and/or reception. Using narrow directional beams may minimize or reduce inter-link interference, thereby increasing network throughput and reducing latency. Thus, the use of mmWav can improve system performance.

In some implementations, the networks100and200may use orthogonal frequency division multiplexing (OFDM) on the downlink and single-carrier frequency division multiplexing (SC-FDM) on the UL. OFDM and SC-FDM partition the system bandwidth into multiple (K) orthogonal subcarriers, which are also commonly referred to as tones, bins, or the like. Each subcarrier may be modulated with data. In general, modulation symbols are sent in the frequency domain with OFDM and in the time domain with SC-FDM. The spacing between adjacent subcarriers may be fixed, and the total number of subcarriers (K) may be dependent on the system bandwidth. The system bandwidth may also be partitioned into subbands.

FIG. 3illustrates a network topology300according to embodiments of the present disclosure. The topology300can be employed by the network200. For example, the BSs105and the UEs115can be configured to form a logical spanning tree configuration as shown in the topology300for communicating access traffic and/or backhaul traffic. The topology300may include an anchor310coupled to an optical fiber link134for communication with a core network (e.g., the core network130). The anchor310may correspond to the BS105cin the network200.

The topology300includes a plurality of logical levels302. In the example ofFIG. 3, the topology300includes three levels302, shown as302a,302b, and302c. In some other embodiments, the topology300can include any suitable number of levels302(e.g., two, three, four, five, or six, etc.). Each level302may include a combination of UEs115and BSs105interconnected by logical links304, shown as304a,304b, and304c. For example, a logical link304between a BS105and a UE115may correspond to a wireless access link125, whereas a logical link304between two BSs105may correspond to a wireless backhaul link234. The BSs105and the UEs115may be referred to as relay nodes in the topology300.

The nodes (e.g., the BSs105) in the level302acan function as relays for the nodes in the level302b, for example, to relay backhaul traffic between the nodes and the anchor310. Similarly, the nodes (e.g., the BSs105) in the level302bcan function as relays for the nodes in the level302c. For example, the nodes in the level302aare parent nodes to the nodes in the level302b, and the nodes in the level302care child nodes to the nodes in level302b. The parent nodes may function as ACF-nodes and the child nodes may function as UEF-nodes.

For example, a BS105may implement both ACF and UEF and may function as an ACF-node and an UEF-node depending on which node the BS is communicating with. For example, a BS105(shown as pattern-filled) in the level302bmay function as an access node when communicating with a BS105or a UE115in the level302c. Alternatively, the BS105may function as a UE when communicating with a BS105in the level302a. When a communication is with a node in a higher level or with a smaller number of hops to the anchor310, the communication is referred to as a UL communication. When a communication is with a node in a lower level or with a greater number of hops to the anchor310, the communication is referred to as a DL communication. In some embodiments, the anchor310may allocate resources for the links304. Mechanisms for scheduling UL and DL transmissions and/or allocating resources based on the topology300are described in greater detail herein.

In addition to logical links304, network topology300may also include additional links306between BSs105. Links306may link BSs that do not have a parent-child relationship in network topology300and may link arbitrary BSs in the same or different layers of the topology. Advantageously, links306, referred to as sidelinks herein, may provide an alternate path for routing communications between BSs105and UEs115. For example, with sidelink306, communications between UE115aand UE115bmay be routed from BS105ato BS105bvia sidelink306, rather than up through layers302band302ato anchor310then back down to UE155b.

FIGS. 4A and 4Bshow possible resource partitioning in accordance with aspects disclosed herein. In an aspect, networks may be constrained interference between nearby BSs and other considerations, such as half-duplex constraints. For example, UL/DL transmissions between BS310and BSs105may be scheduled during a first slot, or time period, while UL/DL transmissions between BSs105and UEs115, may be scheduled during a different slot. Typically, such slots alternate between transmitting and receiving. In an aspect, a third slot may be used for side link communication. This is shown inFIG. 4A, wherein available resources are partitioned between DL, UL and sidelink communications as shown by the line style if the link. The resources may be rotated between the different types of communications in a round robin, or other scheduling scheme.

In another aspect, a BSs105may be able to use beam forming techniques to communicate with neighboring BSs. The use of narrow beams reduces interference to other wireless devices in the network. In such a network, BSs105may communicate without requiring resource allocation from the typical UL/DL slots. This is shown inFIG. 4B, wherein BSs105aand105btransmit to each other in alternate slots. That is, BS105atransmits to BS105bin a first set of slots, 1→2, and BS105btransmits to BS105aduring a second set of slots, 2→1. In an aspect, the slots need not alternate in a fixed 1:1 ratio, but may vary based on load, QoS, and other factors.

FIGS. 5A, 5B, and 5Cillustrate various slot formats that may be used for communications between the nodes ofFIGS. 1 and 2.FIG. 5Ashows exemplary downlink (DL) centric slot500which may be used for transmitting from a higher level node to a lower level node, e.g. BS105to UE115ainFIG. 1 or 2. DL centric slot500includes PDCCH502, PDSCH504, gap506and PUCCH508. PDCCH502is used to send control information such as DL/UL resource assignments, power control commands, paging indicators, and the like, whereas PDSCH504carries application data. Gap506provides time for the receiving device, e.g., UE115, to process PDCCH502and PDSCH504and to reconfigure for transmitting. PUCCH502may be used for the receiver to send uplink control information, such as ACK/NACK and power control signaling back to the sender.

FIG. 5Billustrates uplink (UL) centric slot510which may be used for transmissions from a lower order node to a higher order node. UL centric slot510may include PDCCH512, gap516, and PUSCH518. PUSCH may be used to send data, such as application data. Gap516provides time for the receiving device, e.g., UE115, to process PDCCH512to determine which resources it is allocated in PUSCH518and to turn it transceiver from a receiving mode to a transmitting mode.

FIG. 5Cillustrates sidelink (SL) centric slot520which may be used for transmissions between nodes that are at the same order or level in the network topology. Sidelink slot520, may be used for communications between nodes that are not otherwise directly linked by the logical topology of a network. Sidelink slot520includes PDCCH522and PDSCH524, which serve similar roles to the corresponding slots of downlink centric slot500ofFIGS. 5A and 5B. SL centric slot520may include PDCCH522, PDSCH528, gap526. PDSCH may be used to send data, such as application and other data between BSs105. Gap526provides time for the receiving device, e.g., UE115, to process data in PDSCH526and to turn it transceiver from a receiving mode to a transmitting mode in anticipation or transmitting data in the reverse direction.

FIG. 6illustrates an IAB network resource sharing method600according to embodiments of the present disclosure. The method600illustrates resource partitioning for use in the topology300. InFIG. 6, the x-axis represents time in some constant units (e.g., frames, slots, subslots, msec, symbols, etc.). The method600time-partitions resources in an IAB network (e.g., the network200) into resources610and620. The resources610and620can include time-frequency resources. For example, each resource610or620may include a number of symbols (e.g., OFDM symbols) in time and a number of subcarriers in frequency. In some embodiments, each resource610or620shown may correspond to a subframe, a slot, or a transmission time interval (TTI), which may carry one media access control (MAC) layer transport block.

As will be discussed below, sidelink resources may alternate direction for transmissions: first from BS105ato BS105band then the reverse. Accordingly, rather than providing PUCCH and PUSCH for sidelink slots, the information normally carried in these channels may be carried in the PDCCH or PDSCH when the direction of transmission is reversed.

As an example, the method600may assign the resources610to the links304aand304cin the topology300for communicating UL and/or DL traffic. The method600may assign the resources620to the links304bin the topology300for communicating UL and/or DL traffic. The time-partitioning of the resources in the alternating manner shown in the method600can reduce interference between the different levels302, reducing constraints due to half-duplexing, and reduce transmit-receive gap periods.

FIGS. 7A to 7Cillustrate various aspects of communicating data and control information in sidelink formatted slots. In a first aspect, shown inFIG. 7A, BS105atransmits PDCCH702aincluding scheduling information about which resources in PDSCH704acontain data being transmitted to BS105b. BS105asubsequently transmits the data in PDSCH704ain accordance with the scheduling information transmitted during PDCCH702a. BS105b, having received the scheduling information in PDCCH702a, decodes PDSCH704ato receive the data communicated from BS105a. After gap706, BS105btransmits scheduling information and data during PSCCH702band PDSCH704b. In addition, BS105bmay also transmit control information during PDCCH702b, such as link quality information and ACK/NACK information. In another aspect, BS105bmay transmit the control information during PDSCH714brather than during PDCCH712b, as shown inFIG. 7C.

In an aspect, additional signals and control information may be needed in a narrow beam mmWave environment. For example, BSs105aand105bmay need to be able to determine which beam(s) to use for communication. In an aspect, BS105amay transmit CSI-RS during PDSCH724aby sending CSI-RS signaling over multiple beams in a sweeping manner. BS105bmay communication a desired beam index during subsequent PDCCH722b, as shown inFIG. 7C. In an aspect, BS105bmay alternately communicate beam selection information during PDSCH724b. The preceding described transmissions from BS105ato BS105b, whereas one skilled in the art will understand that transmissions in the reverse direction, e.g., from BS105bto BS105a, are made in an analogous manner.

In an aspect of the invention, sidelink resources830may be interspersed with uplink resources810and downlink resources820, as shown inFIG. 8, so that gap726does not explicitly need to be included in the sidelink slot format. In another aspect, narrow beam mmWave transmissions may obviate the need to time multiplex resources810,820, and830.

Regular PUCCH channels include information needed for downlink transmissions, such as ACK/NAK of downlink traffic, channel quality information (e.g., CQI, RSRP, PMI), scheduling requests, beam index reports, and beam quality reports, among others. Because the sidelink slot format does not include a PUCCH, this information is conveyed through other mechanisms. In one aspect, the PUCCH-type information is conveyed in the PDCCH when a sidelink transmission is sent in the reverse direction. For example, when BS105breceived a transmission from BS105a, the information usually sent during PUCCH is transmitted in the PDCCH when BS105btransmits to BS105a. Advantageously, control channels are typically more robust than data channels. In another aspect, the PUCCH-type information may be conveyed in the PDSCH when a sidelink transmission is sent in the reverse direction. For example, when BS105breceives a transmission from BS105a, the information usually sent during PUCCH may transmitted in PDSCH when BS105btransmits to BS105a.

FIG. 7Dillustrates resource sharing in an IAB network, such as the topology300, according to embodiments of the present disclosure. InFIG. 7D, the x-axis represents time in some constant units (e.g., frames, slots, subslots, msec, etc.). As shown, resources in an IAB network (e.g., the network200) are time-partitioned into resources760,770, and780. The resources may include time-frequency resources. For example, each resource760,770, and780may include a number of symbols (e.g., OFDM symbols) in time and a number of subcarriers in frequency. In some embodiments, each resource760,770, and780shown may correspond to a subframe, a slot, a transmission time interval (TTI), or other convenient interval, which may carry one media access control (MAC) layer transport block.

As an example, in topology300ofFIG. 3, resources760may be assigned to links304aand304cfor communicating UL and/or DL traffic; the resources770may be assigned to the links304bfor communicating UL and/or DL traffic; and the resources780may be assigned to306for communicating sidelink traffic. The time-partitioning of the resources in the alternating manner shown inFIG. 7Dcan reduce interference between the different levels302, overcome the half-duplex constraint, and reduce transmit-receive gap periods.

In an aspect of the present invention, resource partitioning to provide sidelink306is done at a node or anchor having a higher order than the nodes sharing sidelink306, that is, one at a higher level in network topology300. In an aspect, the resource partitioning is done at a common parent of the two nodes using the sidelink. For instance, anchor310may partition network resources into resources310,320, and330for all the nodes inFIG. 3. Partitioning may also be done by non-anchor nodes that are higher than the nodes using the sidelink.

In an aspect of setting up sidelink306, the direction of communication between BSs105aand105bwill typically alternate. That is a resource partition may be used for transmission of data from BS105ato BS105b, then a subsequent resource partition may be used for transmissions from BS105bto BS105a. In some embodiments, the resource partitions may be substantially the same size in terms of time, bandwidth, and the like. In other embodiments, the resource partitions may have different sizes to accommodate different data rates, bandwidth, channel conditions, reliability, quality of service, etc. For example, transmitting video from UE115ato UE115bmay require larger partitions or more partitions for transmission of data from BS105ato BS105bthan are needed to transmit control information in the reverse direction from BS105bto BS105a.

FIG. 8is a block diagram of an exemplary UE800according to embodiments of the present disclosure. The UE800may be a UE115as discussed above. As shown, the UE800may include a processor802, a memory804, an IAB communication module808, a transceiver810including a modem subsystem812and a radio frequency (RF) unit814, and one or more antennas816. These elements may be in direct or indirect communication with each other, for example via one or more buses.

The processor802may include a central processing unit (CPU), a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a controller, a field programmable gate array (FPGA) device, another hardware device, a firmware device, or any combination thereof configured to perform the operations described herein. The processor802may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

The IAB communication module808may be implemented via hardware, software, or combinations thereof. For example, the IAB communication module808may be implemented as a processor, circuit, and/or instructions806stored in the memory804and executed by the processor802. The IAB communication module808may be used for various aspects of the present disclosure. For example, the IAB communication module808is configured to maintain multiple synchronization references, provide synchronization information (e.g., including timing and/or frequency) associated with the synchronization references to other nodes (e.g., the BSs105), receive synchronization information from other nodes, receive synchronization adjustment commands, receive scheduling information (e.g., gap periods, transmission timing, and/or reception timing), adjust synchronization references based on the received synchronization information and/or the received commands, and/or communicate with other nodes based on received scheduling information, as described in greater detail herein.

As shown, the transceiver810may include the modem subsystem812and the RF unit814. The transceiver810can be configured to communicate bi-directionally with other devices, such as the BSs105. The modem subsystem812may be configured to modulate and/or encode the data from the memory804and/or the IAB communication module808according to a modulation and coding method (MCS), e.g., a low-density parity check (LDPC) coding method, a turbo coding method, a convolutional coding method, a digital beamforming method, etc. The RF unit814may be configured to process (e.g., perform analog to digital conversion or digital to analog conversion, etc.) modulated/encoded data from the modem subsystem812(on outbound transmissions) or of transmissions originating from another source such as a UE115or a BS105. The RF unit814may be further configured to perform analog beamforming in conjunction with the digital beamforming. Although shown as integrated together in transceiver810, the modem subsystem812and the RF unit814may be separate devices that are coupled together at the UE115to enable the UE115to communicate with other devices.

The RF unit814may provide the modulated and/or processed data, e.g. data packets (or, more generally, data messages that may contain one or more data packets and other information), to the antennas816for transmission to one or more other devices. This may include, for example, transmission of reservation signals, reservation response signals, and/or any communication signal according to embodiments of the present disclosure. The antennas816may further receive data messages transmitted from other devices. This may include, for example, reception of synchronization information, synchronization adjustment commands, and/or scheduling adjustment information according to embodiments of the present disclosure. The antennas816may provide the received data messages for processing and/or demodulation at the transceiver810. The antennas816may include multiple antennas of similar or different designs in order to sustain multiple transmission links. The RF unit814may configure the antennas816.

FIG. 9is a block diagram of an exemplary BS900according to embodiments of the present disclosure. The BS900may be a BS105as discussed above. A shown, the BS900may include a processor902, a memory904, an IAB communication module908, a transceiver910including a modem subsystem912and a RF unit914, and one or more antennas916. These elements may be in direct or indirect communication with each other, for example via one or more buses.

The memory904may include a cache memory (e.g., a cache memory of the processor902), RAM, MRAM, ROM, PROM, EPROM, EEPROM, flash memory, a solid state memory device, one or more hard disk drives, memristor-based arrays, other forms of volatile and non-volatile memory, or a combination of different types of memory. In some embodiments, the memory904may include a non-transitory computer-readable medium. The memory904may store instructions906. The instructions906may include instructions that, when executed by the processor902, cause the processor902to perform operations described herein. Instructions906may also be referred to as code, which may be interpreted broadly to include any type of computer-readable statement(s) as discussed above with respect toFIG. 7.

The IAB communication module908may be implemented via hardware, software, or combinations thereof. For example, the IAB communication module908may be implemented as a processor, circuit, and/or instructions906stored in the memory904and executed by the processor902. The IAB communication module908may be used for various aspects of the present disclosure. For example, the IAB communication module908is configured to maintain multiple synchronization references, provide synchronization information (e.g., including timing and/or frequency) associated with the synchronization references to other nodes (e.g., the BSs105and the UEs115and800), receive synchronization information from other nodes, receive synchronization adjustment commands, adjust synchronization references based on the received synchronization information or the received commands, receive scheduling information (e.g., gap periods, transmission timing, and/or reception timing) for communication with nodes at a higher level (e.g., less hops away from an anchor115cthan the BS115), determine scheduling information for communication with nodes at a lower level (e.g., more hops away from an anchor115cthan the BS115), and/or communicate with nodes based on the received scheduling information and the determined scheduling information, as described in greater detail herein.

As shown, the transceiver910may include the modem subsystem912and the RF unit914. The transceiver910can be configured to communicate bi-directionally with other devices, such as the UEs115and/or another core network element. The modem subsystem912may be configured to modulate and/or encode data according to a MCS, e.g., a LDPC coding method, a turbo coding method, a convolutional coding method, a digital beamforming method, etc. The RF unit514may be configured to process (e.g., perform analog to digital conversion or digital to analog conversion, etc.) modulated/encoded data from the modem subsystem912(on outbound transmissions) or of transmissions originating from another source such as a UE115. The RF unit914may be further configured to perform analog beamforming in conjunction with the digital beamforming. Although shown as integrated together in transceiver910, the modem subsystem912and the RF unit914may be separate devices that are coupled together at the BS105to enable the BS105to communicate with other devices.

The RF unit914may provide the modulated and/or processed data, e.g. data packets (or, more generally, data messages that may contain one or more data packets and other information), to the antennas916for transmission to one or more other devices. This may include, for example, transmission of information to complete attachment to a network and communication with a camped UE115according to embodiments of the present disclosure. The antennas916may further receive data messages transmitted from other devices and provide the received data messages for processing and/or demodulation at the transceiver910. The antennas916may include multiple antennas of similar or different designs in order to sustain multiple transmission links.

FIG. 10is a flow diagram of a method1000for communicating in an IAB network according to embodiments of the present disclosure. The network may be similar to the networks100and200; and may be configured with the topology300. Steps of the method1000can be executed by a computing device (e.g., a processor, processing circuit, and/or other suitable component) of a wireless communication device, such as the BSs105and800and the UEs115and900. The method1000may employ similar mechanisms as described with respect toFIGS. 3 to 9. As illustrated, the method1000includes a number of enumerated steps, but embodiments of the method1000may include additional steps before, after, and in between the enumerated steps. In some embodiments, one or more of the enumerated steps may be omitted or performed in a different order.

At step1010, the method1000includes transmitting, by the first wireless communication device, a first transmission to the second wireless device during a first one of the plurality of slots.

At step1020, the method1000includes receiving, by the first wireless communication device, a second transmission from the second wireless device during a second one of the plurality of slots, the second transmission including link quality information about the first transmission and scheduling a third transmission between the first and second wireless devices.

In a first aspect, the first wireless communication device transmits a first transmission to a second wireless device during a first one of a plurality of slots; and receives a second transmission from the second wireless device during a second one of the plurality of slots, the second transmission including link quality information about the first transmission and scheduling a third transmission between the first and second wireless devices. In an aspect, the first and second wireless devices do not have a parent child relationship.

In a second aspect, in combination with the first aspect, the first wireless communication device may receive the third transmission from the second wireless communication device. In a third aspect, in combination with the first aspect, the first wireless communication device may transmit the third transmission from the second wireless communication device.

In a fourth aspect, in combination with any of the first to third aspects, the link quality information about the first transmission includes a least one or more combinations of CQI, reference signal received power (RSRP), signal to noise ratio (SNR), reference signal received quality (RSRQ), RSSI, beam index, beam coherence time, and beam quality.

In a fifth aspect, in combination with any of the first to fourth aspects, the second transmission includes one or more of an ACK/NACK for data transmitted during the first transmission, and a scheduling request (SR) for a subsequent communication between the first and second wireless communication devices.

In a sixth aspect, in combination with any of the first to fifth aspects, each of the plurality of slots includes a control channel and a data channel, and the first wireless device is configured to receive one or more of the link quality information, the ACK/NACK, and the SR in one of the control channel or the data channel of the second slot.