Patent Description:
These improvements should be applicable to other multi-access technologies and the telecommunication standards that employ these technologies.

<CIT> discloses a remote UE configured to communicate with an eNB through a relay UE and to perform route switching of network traffic within the MAC layer between a Uu interface and a PC5 interface. The relay UE is configured to couple components across a Uu interface and a PC5, and perform network traffic relaying between the remote UE and the eNB. The eNB is configured to communicate with the remote UE through the relay UE, and perform route switching of network traffic within the MAC layer between a Uu inteface of the remote UE and a Uu interface of the relay UE.

<CIT> discloses provided a method related to layer <NUM> relaying and mobility using a sidelink interface, including a remote user equipment (UE) for use in a wireless communication network, the UE comprising: a device to network (D2N) entity, a device to device (D2D) entity, and control logic to: receive a service data unit derived from an IP packet direct the service data unit to the D2N entity for communication with an eNB using a Uu interface in a first mode of operation, and direct the service data unit to the D2D entity for communication with the eNB via a first relay UE using a sidelink interface in a second, relay, mode of operation.

"<NPL>) is related to LS on 3GPP <NUM> synopsis towards ITU-R Recommendation on IMT-<NUM> Technical Specifications.

The invention is defined in the appended independent claims. Advantageous, optional features are then set out in the accompanying dependent claims.

Certain aspects of the subject matter described in this disclosure provide a method for wireless communication performed by a relay node according to claim <NUM>.

Certain aspects of the subject matter described in this disclosure provide a method for wireless communication performed by a source node according to claim <NUM>.

Certain aspects of the subject matter described in this disclosure can be implemented in an apparatus for wireless communication by a relay node according to claim <NUM>.

Certain aspects of the subject matter described in this disclosure can be implemented in an apparatus for wireless communication by a source node according to claim <NUM>.

Certain aspects of the subject matter described in this disclosure can be implemented in a computer-readable medium according to claim <NUM>.

It is to be noted, however, that the appended drawings illustrate only certain typical aspects of this disclosure and the description may admit to other equally effective aspects.

Aspects of the present disclosure provide apparatus, methods, processing systems, and computer readable mediums for relaying operations. As will be described herein, direct transport block (TB) forwarding may be enabled in relaying operations wherein a TB is transmitted to a destination node without going through the entire protocol stack of the relay node. Accordingly, a TB is transmitted to a destination node through only a Physical (PHY) layer and a portion of the Media Access Control (MAC) layer. In aspects of the present disclosure, the TB is forwarded through the PHY layer and the hybrid automatic repeat request (HARQ) portion of the MAC layer in a protocol stack of a relay node.

In some aspects, a source node may transmit two or more packets, in a concatenated downlink (DL) TB, desired for two or more target nodes through the same relay node, thereby creating a one-to-many relaying operation. In some aspects, a source node may transmit, to a destination node, two or more packets, on different component carriers (CCs) or at different times, through the same relay node, thereby creating a many-to-one relaying operation.

Changes may be made in the function and arrangement of elements discussed without departing from the disclosure. In addition, the disclosure is intended to cover such an apparatus or method which is practiced using other structure, functionality, or structure and functionality in addition to, or other than, the various aspects of the disclosure set forth herein.

For example, the wireless communication network <NUM> may be a New Radio (NR) or <NUM> network. For example, as shown in <FIG>, the UE 120a has a relaying manager that is configured for receiving, from a source node, an indication to directly forward one or more transport blocks (TBs) to one or more destination nodes, wherein directly forwarding includes transmitting a TB of the one or more TBs to the one or more destination nodes through only a Physical (PHY) layer and a hybrid automatic repeat request (HARQ) portion of a Media Access Control (MAC) layer in a protocol stack of the relay node, receiving, from the source node, control information for one or more data channels configuring one downlink (DL) grant and two or more sidelink (SL) grants or two or more DL grants and one SL grant, decoding one or more TBs based, at least in part, on the control information; and directly forwarding the one or more TBs to the one or more destination nodes based, at least in part, on the indication and the control information, according to aspects described herein. For example, as shown in <FIG>, the BS 110a has a relaying manager that is configured for transmitting, to a relay node, an indication to directly forward one or more TBs to one or more destination nodes, wherein directly forwarding includes transmitting a TB of the one or more TBs to the one or more destination nodes through only a PHY layer and a HARQ portion of a MAC layer in a protocol stack of the relay node and transmitting, to the relay node, control information for one or more data channels configuring one DL grant and two or more SL grants or two or more DL grants and one SL grant. , according to aspects described herein.

As illustrated in <FIG>, the wireless communication network <NUM> may include a number of base stations (BSs) <NUM> and other network entities. A BS may be a station that communicates with user equipments (UEs). Each BS <NUM> may provide communication coverage for a particular geographic area. In NR systems, the term "cell" and next generation NodeB (gNB or gNodeB), NR BS, <NUM> NB, access point (AP), or transmission reception point (TRP) may be interchangeable. In some examples, the base stations may be interconnected to one another and/or to one or more other base stations or network nodes (not shown) in wireless communication network <NUM> through various types of backhaul interfaces, such as a direct physical connection, a wireless connection, a virtual network, or the like using any suitable transport network.

A relay station may also be a UE that relays transmissions for other UEs or BSs. UE 120a may also be a relay station used to communicate with BS 110a and a UE <NUM> in order to facilitate communication between the BS 110a and the UE <NUM>. The relay <NUM> may be located within the coverage area 102a. A relay station may also be referred to as a relay BS, a relay UE, a relay, a relay node etc..

A UE may also be referred to as a mobile station, a terminal, an access terminal, a subscriber unit, a station, a Customer Premises Equipment (CPE), a cellular phone, a smart phone, a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a laptop computer, a cordless phone, a wireless local loop (WLL) station, a tablet computer, a camera, a gaming device, a netbook, a smartbook, an ultrabook, an appliance, a medical device or medical equipment, a biometric sensor/device, a wearable device such as a smart watch, smart clothing, smart glasses, a smart wrist band, smartj ewelry (e.g., a smart ring, a smart bracelet, etc.), an entertainment device (e.g., a music device, a video device, a satellite radio, etc.), a vehicular component or sensor, a smart meter/sensor, industrial manufacturing equipment, a global positioning system device, or any other suitable device that is configured to communicate via a wireless or wired medium.

<FIG> illustrates an example architecture of a distributed Radio Access Network (RAN) <NUM>, which may be implemented in the wireless communication network <NUM> illustrated in <FIG>. As shown in <FIG>, the distributed RAN includes Core Network (CN) <NUM> and Access Node <NUM>.

The CN <NUM> may host core network functions. CN <NUM> may be centrally deployed. CN <NUM> functionality may be offloaded (e.g., to advanced wireless services (AWS)), in an effort to handle peak capacity. The CN <NUM> may include the Access and Mobility Management Function (AMF) <NUM> and User Plane Function (UPF) <NUM>. The AMF <NUM> and UPF <NUM> may perform one or more of the core network functions.

The AN <NUM> may communicate with the CN <NUM> (e.g., via a backhaul interface). The AN <NUM> may communicate with the AMF <NUM> via an N2 (e.g., NG-C) interface. The AN <NUM> may communicate with the UPF <NUM> via an N3 (e.g., NG-U) interface. The AN <NUM> may include a central unit-control plane (CU-CP) <NUM>, one or more central unit-user plane (CU-UPs) <NUM>, one or more distributed units (DUs) <NUM>-<NUM>, and one or more Antenna/Remote Radio Units (AU/RRUs) <NUM>-<NUM>. The CUs and DUs may also be referred to as gNB-CU and gNB-DU, respectively. One or more components of the AN <NUM> may be implemented in a gNB <NUM>. The AN <NUM> may communicate with one or more neighboring gNBs.

The CU-CP <NUM> may be connected to one or more of the DUs <NUM>-<NUM>. The CU-CP <NUM> and DUs <NUM>-<NUM> may be connected via a F1-C interface. As shown in <FIG>, the CU-CP <NUM> may be connected to multiple DUs, but the DUs may be connected to only one CU-CP. Although <FIG> only illustrates one CU-UP <NUM>, the AN <NUM> may include multiple CU-UPs. The CU-CP <NUM> selects the appropriate CU-UP(s) for requested services (e.g., for a UE). The CU-UP(s) <NUM> may be connected to the CU-CP <NUM>. For example, the DU-UP(s) <NUM> and the CU-CP <NUM> may be connected via an E1 interface. The CU-CP(s) <NUM> may be connected to one or more of the DUs <NUM>-<NUM>. The CU-UP(s) <NUM> and DUs <NUM>-<NUM> may be connected via a F1-U interface. As shown in <FIG>, the CU-CP <NUM> may be connected to multiple CU-UPs, but the CU-UPs may be connected to only one CU-CP.

A DU, such as DUs <NUM>, <NUM>, and/or <NUM>, may host one or more TRP(s) (transmit/receive points, which may include an Edge Node (EN), an Edge Unit (EU), a Radio Head (RH), a Smart Radio Head (SRH), or the like). A DU may be located at edges of the network with radio frequency (RF) functionality. A DU may be connected to multiple CU-UPs that are connected to (e.g., under the control of) the same CU-CP (e.g., for RAN sharing, radio as a service (RaaS), and service specific deployments). DUs may be configured to individually (e.g., dynamic selection) or jointly (e.g., joint transmission) serve traffic to a UE. Each DU <NUM>-<NUM> may be connected with one of AU/RRUs <NUM>-<NUM>.

The CU-CP <NUM> may be connected to multiple DU(s) that are connected to (e.g., under control of) the same CU-UP <NUM>. Connectivity between a CU-UP <NUM> and a DU may be established by the CU-CP <NUM>. For example, the connectivity between the CU-UP <NUM> and a DU may be established using Bearer Context Management functions. Data forwarding between CU-UP(s) <NUM> may be via a Xn-U interface.

The distributed RAN <NUM> may support fronthauling solutions across different deployment types. For example, the RAN <NUM> architecture may be based on transmit network capabilities (e.g., bandwidth, latency, and/or jitter). The distributed RAN <NUM> may share features and/or components with LTE. For example, AN <NUM> may support dual connectivity with NR and may share a common fronthaul for LTE and NR. The distributed RAN <NUM> may enable cooperation between and among DUs <NUM>-<NUM>, for example, via the CU-CP <NUM>. An inter-DU interface may not be used.

Logical functions may be dynamically distributed in the distributed RAN <NUM>. As will be described in more detail with reference to <FIG>, the Radio Resource Control (RRC) layer, Packet Data Convergence Protocol (PDCP) layer, Radio Link Control (RLC) layer, Medium Access Control (MAC) layer, Physical (PHY) layers, and/or Radio Frequency (RF) layers may be adaptably placed, in the AN and/or UE.

<FIG> illustrates a diagram showing examples for implementing a communications protocol stack <NUM> in a RAN (e.g., such as the RAN <NUM>), according to aspects of the present disclosure. The illustrated communications protocol stack <NUM> may be implemented by devices operating in a wireless communication system, such as a <NUM> NR system (e.g., the wireless communication network <NUM>). In various examples, the layers of the protocol stack <NUM> may be implemented as separate modules of software, portions of a processor or ASIC, portions of non-collocated devices connected by a communications link, or various combinations thereof. Collocated and non-collocated implementations may be used, for example, in a protocol stack for a network access device or a UE. As shown in <FIG>, the system may support various services over one or more protocols. One or more protocol layers of the protocol stack <NUM> may be implemented by the AN and/or the UE.

As shown in <FIG>, the protocol stack <NUM> is split in the AN (e.g., AN <NUM> in <FIG>). The RRC layer <NUM>, PDCP layer <NUM>, RLC layer <NUM>, MAC layer <NUM>, PHY layer <NUM>, and RF layer <NUM> may be implemented by the AN. For example, the CU-CP (e.g., CU-CP <NUM> in <FIG>) and the CU-UP e.g., CU-UP <NUM> in <FIG>) each may implement the RRC layer <NUM> and the PDCP layer <NUM>. A DU (e.g., DUs <NUM>-<NUM> in <FIG>) may implement the RLC layer <NUM> and MAC layer <NUM>. The AU/RRU (e.g., AU/RRUs <NUM>-<NUM> in <FIG>) may implement the PHY layer(s) <NUM> and the RF layer(s) <NUM>. The PHY layers <NUM> may include a high PHY layer and a low PHY layer.

The UE may implement the entire protocol stack <NUM> (e.g., the RRC layer <NUM>, the PDCP layer <NUM>, the RLC layer <NUM>, the MAC layer <NUM>, the PHY layer(s) <NUM>, and the RF layer(s) <NUM>).

<FIG> illustrates example components ofBS <NUM> and UE <NUM> (as depicted in <FIG>), which may be used to implement aspects of the present disclosure. For example, antennas <NUM>, processors <NUM>, <NUM>, <NUM>, and/or controller/processor <NUM> of the UE <NUM> and/or antennas <NUM>, processors <NUM>, <NUM>, <NUM>, and/or controller/processor <NUM> of the BS <NUM> may be used to perform the various techniques and methods described herein. As shown in <FIG>, the processor <NUM> has a relaying manager that is configured for transmitting, to a relay node, an indication to directly forward one or more TBs to one or more destination nodes, wherein directly forwarding includes transmitting a TB of the one or more TBs to the one or more destination nodes through only a PHY layer and a HARQ portion of a MAC layer in a protocol stack of the relay node and transmitting, to the relay node, control information for one or more data channels configuring one DL grant and two or more SL grants or two or more DL grants and one SL grant. , according to aspects described herein. As shown in <FIG>, the processor <NUM> has a relaying manager that is configured for configured for receiving, from a source node, an indication to directly forward one or more TBs to one or more destination nodes, wherein directly forwarding includes transmitting a TB of the one or more TBs to the one or more destination nodes through only a PHY layer and a HARQ portion of a MAC layer in a protocol stack of the relay node, receiving, from the source node, control information for one or more data channels configuring one DL grant and two or more SL grants or two or more DL grants and one SL grant, decoding one or more TBs based, at least in part, on the control information; and directly forwarding the one or more TBs to the one or more destination nodes based, at least in part, on the indication and the control information, according to aspects described herein.

The controllers/processors <NUM> and <NUM> may direct the operation at the BS <NUM> and the UE <NUM>, respectively.

In some examples, the sidelink signals may be communicated using a licensed spectrum (unlike wireless local area networks, which may use an unlicensed spectrum).

In the context of LTE, relaying implies that a device (e.g., destination node) communicates with a network via a relay node which is wirelessly connected to a source node via LTE radio interface, Un, a modified version of evolved terrestrial radio access network (E-UTRAN) air interface Uu. The source node may also serve its own UE as usual, in addition to sharing its radio resources for relay nodes.

As mentioned previously, in relaying operations, a relay node (also referred to herein as a relay station) is a node that receives a transmission of data and/or other information from an upstream node (e.g., source node) on a link between the source node and the upstream node. After receipt of the transmission, the relay node sends a transmission of the data and/or other information to a downstream node (e.g., a destination node) on a link between the relay node and the destination node.

<FIG> illustrates an example relaying operation where a TB size supported by a link between a source node and a relay node is not supported by a link between the relay node and a destination node. In the example relaying shown in <FIG>, a relay node communicates with a source node and a destination node in order to facilitate communication (i.e., send data) between the source node and the destination node. Data received from the source node may be transmitted up and down a protocol stack, at the relay node, before the relay node is able to send the data to the destination node. As shown in <FIG>, the relay node receives the TB from the source node. The TB moves up the relay node's protocol stack through the PHY, MAC, RLC, and PDCP layers and back down the relay node's protocol stack through the PDCP, RCL, MAC, and PHY layers before the TB is transmitted to the destination node.

<FIG> illustrates example packet processing through a communication protocol stack, in accordance with certain aspects of the present disclosure. In a wireless communication network, a packet of information may flow through several sub-layers of the communication protocol stack as it travels from one node to another. As shown in <FIG>, the <NUM> new radio (NR) protocol stack is illustrated with the higher layers on top, such that an IP packet progresses downward through the stack. The packet enters the protocol stack through the service data adaptation protocol (SDAP) layer and travels down the protocol stack through PDCP layer, a RLC layer, and MAC layer. Each protocol layer may manipulate the data by adding header or subheader information (e.g., H as illustrated in <FIG>), converting the data into different formats, and/or combining packets to form larger packets. The MAC layer generates a MAC protocol data unit (PDU) which may include multiple MAC SDUs or only one MAC SDU. Essentially, the MAC PDU becomes the PHY SDU (which may be called a TB) when transmitted to the PHY layer. When the receiving station receives the data, the data may work its way back up through a protocol stack at the receiving station. The protocol at each layer may reverse the processing that was done by the corresponding layer by the transmitting node; headers may be removed, data may be converted back to its original format, packets that were split into smaller packets may be recombined into larger messages, and so on.

Once the data has progressed through the PHY, MAC, RLC, PDCP, and SDAP layers, the IP packet may either be used or again progress downward through the protocol layers and be sent to a second receiving node. For example, where the receiving station is also a relay node, the packet may again progress downward through the protocol layers such that the TB is in a format supported by a link between the relay node and a destination node. Thus, when the packet reaches the PHY layer, it may again be sent to a destination node.

In some aspects, one-to-many and/or many-to-one relaying operations may be implemented to transmit multiple packets of data and/or other information to one or more targeted destination nodes, through a relay node.

<FIG> illustrate example one-to-many and many-to-one relaying operations, in accordance with certain aspects of the present disclosure. One-to-many relaying operations may involve transmitting multiple packets in a single TB, wherein each IP packet is transmitted to a different destination node through a single relay node. For example, as shown in the example of <FIG>, the source node may transmit internet protocol (IP) packet <NUM> and IP packet <NUM> targeted for destination node <NUM> and destination node <NUM>, respectively, on a single DL transmission (or on a single component carrier (CC)) and through the same relay node. At the relay node, the DL TB (also referred to herein as the PHY SDU, which essentially becomes the MAC PDU as it moves up the protocol stack) may be split into two MAC sub-PDUs and transmitted to their respective targeted destination nodes. Each MAC sub-PDU represents its corresponding packet after the packet has traveled down the protocol stack through the PDCP layer, the RLC layer, and the MAC layer (i.e., each MAC sub-PDU corresponds to an IP packet which has been converted into different formats, combined with other packets, and/or manipulated with header or subheader information). Alternatively, many-to-one relaying operations may involve transmitting multiple IP packets in more than one transmission (or on different CCs), wherein the IP packets are desired for the same destination node. As shown in the example of <FIG>, the source node transmits, through a single relay node, TB <NUM> (including IP packet <NUM>) on a first DL transmission (or on a first CC) and TB <NUM> (including IP packet <NUM>) on a second DL transmission (or on a second CC). Both IP packet <NUM> and IP packet <NUM> are targeted for the same destination node. Accordingly, at the relay node, TB1 and TB2 (also referred to herein as PHY SDU <NUM> and PHY SDU <NUM>, which essentially becomes MAC PDU <NUM> and MAC PDU <NUM> as it moves up the protocol stack) are concatenated into a single TB for transportation to the destination node.

Accordingly, in some cases, it may be advantageous to directly forward a TB to a destination node without the need for packet processing through all layers of the <NUM> NR protocol stack. Additionally, it may be advantageous to concatenate or split MAC PDUs at the relay node when the data transmitted includes multiple IP packets and/or data is targeted for multiple destination nodes.

Certain aspects provide techniques for direct TB forwarding in one-to-many and many-to-one relaying operations. More specifically, the present disclosure provides techniques for transmitting, from a relay node, one or more TBs to one or more destination nodes through only a PHY layer and a hybrid automatic repeat request (HARQ) portion of a MAC layer in a protocol stack of the relay node.

Certain aspects of the present disclosure provide apparatus, methods, processing systems, and computer readable mediums for relaying operations. For example, certain aspects provide techniques and apparatus for direct transport block (TB) forwarding in one-to-many and many-to-one relaying operations.

As mentioned above, when a link between a source node and a relay node (e.g., source-relay link) supports a TB size different than a TB size supported by a link between the source node and a destination node (e.g., relay-destination link), then a normal relaying scheme may be implemented, requiring data to be processed (i.e., transmitted up and down the <NUM> new radio (NR) protocol stack at the relay node) before transmission to the destination node. However, in some cases where the source-relay link and the relay-destination link support the same TB size, in accordance with aspects of the present disclosure, the relay node may directly forward the TB, received from the source node, to the destination node. As used herein, directly forwarding the TB refers to a relay node transmitting a TB to a destination node without the TB going through the relay node's complete protocol stack.

<FIG> illustrates an example relaying operation where a source-relay link and a relay-destination link support the same TB size, in accordance with certain aspects of the present disclosure. In the example relaying operation shown in <FIG>, a relay node communicates with a source node and a destination node in order to transmit data between the source node and the destination node. Data received from the source node is forwarded directly to the destination node. Direct forwarding includes transmitting a TB to the destination node through only a physical (PHY) layer and a hybrid automatic repeat request (HARQ) portion of a media access control (MAC) layer in a protocol stack of the relay node. Instead of processing the packet up and down each layer in the protocol stack, the relay node may demodulate and decode the received PHY layer data channel from the source node (e.g., demodulate and decode the TB) and then encode and modulate the TB, such that it may be forwarded to the destination node. The MAC layer of the protocol stack at the relay node is also involved in the TB forwarding process because the MAC layer controls the HARQ process. For example, if a first transmission from the relay node to the destination node fails, then the MAC layer may need to perform HARQ. While the MAC layer may be involved in the direct TB forwarding, the MAC protocol data unit (PDU) may not be changed at the relay node.

To enable direct TB forwarding in relaying operations, resources may be allocated such that the source-relay link and the relay-destination link support the same TB size. Resource allocation (which may be performed by the source node) may include determining a number of identifications (IDs) to allocate for each link and determining a modulation and coding scheme (MCS) to be selected for each link based on link quality, respective to each of the source-relay link and the relay-destination link.

Additionally, the relay node may know whether it should use a normal relaying scheme or use the direct TB forwarding scheme. In particular, the relay node is instructed by the source node to use direct TB forwarding (i.e., the source node sends, to the relay node, an indication to directly forward the TB).

In aspects of the present disclosure, one-to-many and many-to-one relaying operations may be used when the data transmitted includes multiple internet protocol (IP) packets and/or multiple targeted destination nodes.

In some aspects, a relay node may receive a single TB, in accordance with a downlink (DL) grant, to be forwarded to multiple destination nodes. The TB may include two or more concatenated MAC sub-protocol data units (MAC sub-PDUs) corresponding to two or more IP packets. Accordingly, the relay node may be capable of splitting the TB into two or more MAC sub-PDUs and directly forwarding the MAC sub-PDUs to multiple destination nodes.

In some aspects, a relay node receives multiple TBs, in accordance with multiple DL grants, to be forwarded to a single destination node. Each TB received includes a single MAC sub-PDU corresponding to a single IP packet. Accordingly, the relay node is capable of concatenating the MAC sub-PDUs in a concatenated TB and directly forwarding the concatenated TB to a single destination node.

<FIG> is a flow diagram illustrating example operations <NUM> for wireless communication, in accordance with certain aspects of the present disclosure. The operations <NUM> is performed by a relay node (e.g., such as a UE <NUM> or relay station 110r in the wireless communication network <NUM>). The operations <NUM> may be complementary operations by the relay node to the operations <NUM> performed by the source node (e.g., such as a BS <NUM> in the wireless communication network <NUM>). Operations <NUM> may be implemented as software components that are executed and run on one or more processors (e.g., processor <NUM> of <FIG>). Further, the transmission and reception of signals by the relay node in operations <NUM> may be enabled, for example, by one or more antennas (e.g., antennas <NUM> of <FIG>). In certain aspects, the transmission and/or reception of signals by the relay node may be implemented via a bus interface of one or more processors (e.g., processor <NUM>) obtaining and/or outputting signals.

The operations <NUM> begin, at block <NUM>, by a relay node, receiving, from a source node, an indication to directly forward one or more TBs to one or more destination nodes, wherein directly forwarding includes transmitting a TB of the one or more TBs to the one or more destination nodes through only a PHY layer and a HARQ portion of a MAC layer in a protocol stack of the relay node. At block <NUM>, the relay node, receives, from the source node, control information for one or more data channels configuring one DL grant and two or more sidelink (SL) grants or two or more DL grants and one SL grant. At block <NUM>, the relay node decodes one or more TBs based, at least in part, on the control information. At block <NUM>, the relay node directly forwards the one or more TBs to the one or more destination nodes based, at least in part, on the indication and the control information.

<FIG> is a flow diagram illustrating example operations <NUM> for wireless communication, in accordance with certain aspects of the present disclosure. The operations <NUM> are performed by a source node (e.g., such as a BS <NUM> in the wireless communication network <NUM>). Operations <NUM> may be implemented as software components that are executed and run on one or more processors (e.g., processor <NUM> of <FIG>). Further, the transmission and reception of signals by the source node in operations <NUM> may be enabled, for example, by one or more antennas (e.g., antennas <NUM> of <FIG>). In certain aspects, the transmission and/or reception of signals by the source node may be implemented via a bus interface of one or more processors (e.g., processor <NUM>) obtaining and/or outputting signals.

The operations <NUM> begin, at block <NUM>, by the source node transmitting, to a relay node, an indication to directly forward one or more TBs to one or more destination nodes, wherein directly forwarding includes transmitting a TB of the one or more TBs to the one or more destination nodes through only a PHY layer and a HARQ portion of a MAC layer in a protocol stack of the relay node. At block <NUM>, the source node transmits, to the relay node, control information for one or more data channels configuring one DL grant and two or more SL grants or two or more DL grants and one SL grant.

Operations of <FIG> and <FIG> may be understood with reference to <FIG>, <FIG>, and <FIG>, which illustrate direct TB forwarding in one-to-many and many-to-one relaying operations. In some examples, a relay node may know to use direct TB forwarding in the relaying operation based on an indication, sent by a source node, to directly forward a TB to a destination node.

<FIG> is a call flow diagram <NUM> illustrating example signaling for one-to-many relaying operations in SL transmission mode <NUM>, in accordance with aspects of the present disclosure. In NR, there are generally two basic SL resource allocation modes. According to a first mode (Mode <NUM>), as shown in <FIG>, a source node <NUM> may allocate resources for SL communications between a relay node <NUM> and destination nodes <NUM> and <NUM>.

In one-to-many relaying operations, a relay node may receive a single TB, in accordance with a downlink (DL) grant, to be forwarded to multiple destination nodes. The TB may include two or more concatenated MAC sub-PDUs corresponding to two or more IP packets. Specifically, the MAC layer of the source node's protocol stack may map several service data units (SDUs) to a MAC SDU. Further, multiple MAC SDUs may be concatenated to generate a MAC PDU (essentially a TB) with multiple MAC sub-PDUs (including their headers). Because the source node has the capability to concatenate multiple MAC sub-PDUs into a single TB, the source node may also know the size of each of the concatenated MAC sub-PDUs in the TB. Accordingly, the source node may allocate corresponding SL resources for the direct TB forwarding of MAC sub-PDUs to each targeted destination node in the relaying operation.

The one-to-many relaying operation of <FIG>, may begin, at <NUM>, by the relay node <NUM> transmitting, to the source node <NUM>, one or more channel quality indicator (CQI) indices. In some examples, one of the CQI indices may comprise SL CQI for a link between the relay node <NUM> and the destination node <NUM>. In some examples, one of the CQI indices may comprise SL CQI for a link between the relay node <NUM> and the destination node <NUM>. In some examples, one of the CQI indices may comprise a DL CQI for a link between the relay node <NUM> and the source node <NUM>.

At <NUM>, based on the received CQI indices, the source node <NUM> may perform resource allocation. In some aspects, where a SL CQI is received from the relay node <NUM>, the source node <NUM> may allocate SL resources for a SL grant (e.g., a grant for the TB includes a SL grant) based on the SL CQI. In some aspects, where a DL CQI is received from the relay node <NUM>, the source node <NUM> may allocate DL resources for a DL grant (e.g., a grant for the TB includes a DL grant) based on the DL CQI. The source node may allocate resources for a SL grant and a DL grant such that the TB size supported by the source-relay link (e.g., DL), the relay-destination link for destination node <NUM> (e.g., SL for destination node <NUM>), and the relay-destination link for destination node <NUM> (e.g., SL for destination node <NUM>) support the same TB size. In other words, a first TB size supported by the source-relay link, a second TB size supported by the relay-destination link for destination node <NUM>, and a third TB size supported by the relay-destination link for destination node <NUM> may be the same.

At <NUM>, the source node <NUM> may transmit to the relay node <NUM> control information for one or more data channels for decoding a TB. In the one-to-many relaying operation, the source node <NUM> may transmit two packets for two destination nodes (e.g., destination nodes <NUM> and <NUM>) through the same relay node <NUM>, thus, the control information transmitted by the source node <NUM> to the relay node <NUM> may configure one DL grant and two SL grants. In some examples, the DL grant and the two SL grants may be separate. In some examples, the DL grant and the two SL grants may be joined to form one joint DL/SL grant.

In some examples, the control information may further configure one or more length fields of one or more MAC sub-PDUs concatenated in a single TB during many-to-one relaying operations. Thus, a joint DL/SL grant transmitted by the source node <NUM> to the relay node <NUM> may include the DL grant, two SL grants, and a length of one MAC sub PDU in a single format. The source node may configure MAC sub-PDU length fields in the control information because the source node knows the size of each MAC sub-PDU prior to concatenating the MAC sub-PDUs in a single TB for transmission.

At <NUM>, the source node <NUM> may transmit a single TB in accordance with the DL grant. The transmitted TB may comprise two concatenated MAC sub-PDUs corresponding to two IP packets. More specifically, a first IP packet targeted for destination node <NUM> and a second IP packet targeted for destination node <NUM> may be concatenated in a single DL TB transmitted, by the source node <NUM>, to the relay node <NUM>.

At <NUM>, the source node <NUM> may further send an indication, to the relay node <NUM>, to directly forward two TBs (e.g., two MAC sub-PDUs split from the received DL TB) to a destination node, wherein directly forwarding includes transmitting the two TBs to the destination nodes <NUM> and <NUM> through only a PHY layer and a HARQ portion of a MAC layer in a protocol stack of the relay node <NUM>. In some examples, the indication may include a <NUM>-bit indication in either the SL grants alone or in the SL grants which are part of the joint DL/SL grant. In some examples, the indication may be sent via radio resource control (RRC) signaling. An RRC pre-configured relay node <NUM> may be configured to perform direct TB forwarding in all relaying transmissions.

Following receipt of the control information, at <NUM>, the relay node <NUM> may decode the TB based, at least in part, on the control information. At <NUM>, the relay node <NUM> may use the length field in the control information to split the received concatenated TB at the PHY layer into two MAC sub-PDUs (each MAC sub-PDU targeted for either destination node <NUM> or destination node <NUM>).

At <NUM>, the relay node <NUM> may determine, based on the indication, to transmit the two MAC sub-PDUs through only a PHY layer and a HARQ portion of a MAC layer in the protocol stack at the relay node <NUM> (as opposed to processing the packet up and down the protocol stack). Subsequently, the relay node <NUM> may directly forward, at <NUM> and <NUM>, respectively, one of the MAC sub-PDUs to destination node <NUM> and the other MAC sub-PDU to destination node <NUM>.

The control information includes an identification (ID) indicating the destination node <NUM> to which the relay node <NUM> may directly forward the TB to. Accordingly, the relay node <NUM> may directly forward, at <NUM>, the TB to the destination node <NUM> which corresponds to the received ID.

<FIG> illustrates splitting of the MAC PDU in an example <NUM> one-to-many relaying operation. As shown in <FIG>, IP packet <NUM> and IP packet <NUM> may progress downward through several sub-layers, along logical channel <NUM> and logical channel <NUM>, respectively, of the communication protocol stack at the source node (e.g., gNB). Each protocol layer may manipulate the data by adding header or subheader information (e.g., H as illustrated in <FIG>), convert the data into different formats, and combine IP packet <NUM> and IP packet <NUM> into a larger packet. The MAC layer may generate a MAC PDU which concatenates the two MAC SDUs corresponding to IP packet <NUM> and <NUM>. Essentially, the MAC PDU becomes the PHY SDU (which may be called a TB) when transmitted to the PHY layer of the relay node.

When the PHY SDU is transmitted, by the source node, to the relay node, the relay node may split the concatenated PHY SDU into two MAC sub-PDUs based, at least in part, on the one or more length fields (configured by the source node in the control information transmitted to the relay node) of the one or more MAC sub-PDUs. More specifically, the relay node may split the PHY SDU into a first MAC sub-PDU and a second MAC sub-PDU at point <NUM>. The relay node may determine the splitting point <NUM> of the PHY SDU based on the length field for the first MAC sub-PDU in the joint DL/SL grant transmitted by the source node. The first MAC sub-PDU may be directly forwarded to a first destination node (e.g., Targeted UE1). The second MAC sub-PDU may be directly forwarded to a second destination node (e.g., Targeted UE2).

While <FIG> and <FIG> are directed to the transmission of two packets in a one-to-many relaying operation, similar operations may be applied when more than two packets are transmitted. Accordingly, multiple SL grants and multiple length fields for each MAC sub-PDU in a joint DL/SL grant may be configured such that the received DL TB may be split into multiple (e.g., <NUM> or more) MAC sub-PDUs and transmitted to multiple (e.g., <NUM> or more) destination nodes accordingly.

<FIG> is a call flow diagram <NUM> illustrating example signaling for many-to-one relaying operations in SL transmission mode <NUM>, in accordance with aspects of the present disclosure. In many-to-one relaying operations, a relay node receives two or more TBs, in accordance with two or more DL grants, to be forwarded to a single destination node. Each TB includes a MAC sub-PDU corresponding to a single IP packet. To enable relaying of multiple TBs to a single destination node, the source node may instruct the relay node to perform TB concatenation. Specifically, multiple MAC sub-PDUs are concatenated, at the relay node, to generate a MAC PDU (essentially a concatenated TB) with multiple MAC sub-PDUs (including their headers). Because the source node may know the number of TBs (with single MAC sub-PDUs) to be transmitted to the relay node, the source node may know the total DL TB size. Thus, the source node allocates corresponding SL resources for the direct forwarding of a concatenated TB to a targeted destination node.

Similar to <FIG>, in <FIG>, the relay node <NUM> may transmit CQI information to the source node <NUM>, the source node <NUM> may allocate resources based, at least in part, on the CQI, and the source node <NUM> transmits, to the relay node <NUM>, control information and an indication to directly forward one or more TBs to one or more destination nodes. However, unlike the one-to-many relaying operation of <FIG>, the many-to-one relaying operation in <FIG> illustrates transmission of multiple packets to only one destination node (e.g., destination node <NUM>). Therefore, CQI information may include two DL CQIs and one SL CQI. Additionally, control information configures two DL grants and only one SL grant.

Further, at <NUM>, the source node <NUM> transmits two TBs in accordance with the two DL grants, wherein each TB comprises one MAC sub-PDU corresponding to a single IP packet. At <NUM>, the relay node <NUM> decodes the two TBs based on the received control information. At <NUM>, the relay node <NUM> concatenates the two MAC sub-PDUs in a concatenated TB (essentially combining both DL TBs in a single concatenated TB).

At <NUM>, the relay node <NUM> determines, based on the indication, to transmit the concatenated TB through only a PHY layer and a HARQ portion of a MAC layer in the protocol stack at the relay node <NUM> (as opposed to processing the packet up and down the protocol stack). Subsequently, the relay node <NUM> directly forwards, at <NUM>, the concatenated TB to destination node <NUM>.

In some examples, all transmitted packets (one packet per transmitted TB) may not be received by the relay node <NUM>. If the source node <NUM> has sufficient time to receive hybrid automatic repeat request (HARQ) acknowledgement (ACK) or negative acknowledgement (NACK) feedback from the relay node <NUM>, then the relay node <NUM> may transmit, to the source node <NUM>, HARQ ACK feedback for received TBs and HARQ NACK feedback for TBs not received but transmitted by the source node <NUM>. Based on the ACK/NACK feedback, the source node <NUM> may know which TBs were received by the relay node <NUM> and allocate corresponding SL resources accordingly. Thus, the SL grant transmitted, from the source node <NUM>, to the relay node <NUM> is based, at least in part, on the number of received TBs at the relay node <NUM>.

In some examples, all transmitted packets (one packet per transmitted TB) may not be received by the relay node <NUM>, and the source node <NUM> may not have sufficient time to receive HARQ ACK/NACK feedback from the relay node <NUM>. Accordingly, the source node <NUM> may perform TB matching and SL resource allocation for all possible combinations of TBs that potentially could be received at the relay node <NUM>.

In some examples, the source node <NUM> may perform TB matching and SL resource allocation by configuring the SL grant with one or more SL grants, each corresponding to a separate TB transmitted by the source node or one or more combinations of SL grants, wherein each SL grant corresponds to a separate TB transmitted by the source node. For example, when <NUM> packets are transmitted in a many-to-one relaying operation which does not provide sufficient time for the relay node to receive ACK/NACK feedback, the source node may allocate resources for a grant such that the grant includes a DL grant for packet <NUM>'s TB, a DL grant for packet <NUM>'s TB, a SL grant if only packet <NUM>'s TB is received at the relay node, a SL grant if only packet <NUM>'s TB is received at the relay node, and a SL grant if both packet <NUM> and packet's TBs are received at the relay node. In another example involving transmission of <NUM> packets, the source node may allocate resources for a grant such that the grant includes <NUM> DL grants (one for each packet's TB) and <NUM> SL grants (e.g., a SL grant if only packet <NUM>'s TB is received, a SL grant if only packet <NUM>'s TB is received, a SL grant if only packet <NUM>'s TB is received, a SL grant if only packet <NUM> and <NUM>'s TBs are received, a SL grant if only packet <NUM> and <NUM>'s TBs are received, a SL grant if only packet <NUM> and <NUM>'s TBs are received, and a SL grant if all packet <NUM>, <NUM> and <NUM>'s TBs are received). Thus, as the number of transmitted packets increases, the number of SL grants configured by the source node exponentially increases.

Allocating resources for all possible cases does not scale with the number of concatenated packets transmitted from the source node to the relay node; therefore, grant overhead is increased as the number of transmitted packets increases. To reduce grant overhead, in some examples where TB size for each of the packets transmitted is the same, the source node <NUM> may perform TB matching and SL resource allocation by configuring the SL grant with one or more SL grants corresponding to one or more TBs received by the relay node, wherein the one or more TBs received by the relay node is less than or equal to a number of TBs transmitted by the source node. The source node may allocate resources for a grant such that the grant includes a DL grant for all packets transmitted (e.g., DL grant for packet <NUM>, packet <NUM>. , packet n), a SL grant if only one packet is received, a SL grant if only two packets are received, and other SL grants up to a SL grant if all packets transmitted are received. For example, when three packets are transmitted in a many-to-one relaying operation which does not provide sufficient time for the relay node to receive ACK/NACK feedback and the TB size for each packet is the same, the source node may allocate resources for a grant such that the grant includes a DL grant for packet <NUM>, <NUM> and <NUM>, a SL grant if only <NUM> packet is received, a SL grant if only <NUM> packets are received, and a SL grant if all packets are received.

In the foregoing examples, the relay node may select one of the configured SL grants based, at least in part, on a number of the one or more received TBs, concatenates the one or more received TBs in a concatenated TB, and directly forwards the concatenated TB to one destination node based. The relay node directly forwards the concatenated TB based on the indication to directly forward, an ID of a destination node, and the selected configured SL grant.

While <FIG> is directed to the transmission of two packets in a many-to-one relaying operation, similar operations may be applied when more than two packets are transmitted. Accordingly, multiple DL grants a may be configured for transmission of multiple DL TBs such that the received DL TBs may be concatenated in a single TB and transmitted to a single destination node.

The processing system <NUM> includes a processor <NUM> coupled to a computer-readable medium/memory <NUM> via a bus <NUM>. In certain aspects, the computer-readable medium/memory <NUM> is configured to store instructions (e.g., computer-executable code) that when executed by the processor <NUM>, cause the processor <NUM> to perform the operations illustrated in <FIG>, or other operations for performing the various techniques discussed herein for direct TB forwarding in relaying operations. In certain aspects, computer-readable medium/memory <NUM> stores code <NUM> for receiving (e.g., for receiving, from a source node, an indication to directly forward one or more TBs to one or more destination nodes, wherein directly forwarding includes transmitting a TB of the one or more TBs to the one or more destination nodes through only a PHY layer and a HARQ portion of a MAC layer in a protocol stack of the relay node); code <NUM> for receiving (e.g., for receiving, from the source node, control information for one or more data channels configuring one DL grant and two or more SL grants or two or more DL grants and one SL grant); code <NUM> for decoding (e.g., for decoding one or more TBs based, at least in part, on the control information); and code <NUM> for directly forwarding (e.g., directly forwarding the one or more TBs to the one or more destination nodes based, at least in part, on the indication and the control information). In certain aspects, the processor <NUM> has circuitry configured to implement the code stored in the computer-readable medium/memory <NUM>. The processor <NUM> includes circuitry <NUM> for receiving (e.g., for receiving, from a source node, an indication to directly forward one or more TBs to one or more destination nodes, wherein directly forwarding includes transmitting a TB of the one or more TBs to the one or more destination nodes through only a PHY layer and a HARQ portion of a MAC layer in a protocol stack of the relay node); circuitry <NUM> for receiving (e.g., for receiving, from the source node, control information for one or more data channels configuring one DL grant and two or more SL grants or two or more DL grants and one SL grant); circuitry <NUM> for decoding (e.g., for decoding one or more TBs based, at least in part, on the control information); and circuitry <NUM> for directly forwarding (e.g., directly forwarding the one or more TBs to the one or more destination nodes based, at least in part, on the indication and the control information).

The processing system <NUM> includes a processor <NUM> coupled to a computer-readable medium/memory <NUM> via a bus <NUM>. In certain aspects, the computer-readable medium/memory <NUM> is configured to store instructions (e.g., computer-executable code) that when executed by the processor <NUM>, cause the processor <NUM> to perform the operations illustrated in <FIG>, or other operations for performing the various techniques discussed herein for direct TB forwarding in relaying operations. In certain aspects, computer-readable medium/memory <NUM> stores code <NUM> for transmitting (e.g., for transmitting, to a relay node, an indication to directly forward one or more TBs to one or more destination nodes, wherein directly forwarding includes transmitting a TB of the one or more TBs to the one or more destination nodes through only a PHY layer and a HARQ portion of a MAC layer in a protocol stack of the relay node) and code <NUM> for transmitting (e.g., for transmitting, to the relay node, control information for one or more data channels configuring one DL grant and two or more SL grants or two DL grants and one SL grant). In certain aspects, the processor <NUM> has circuitry configured to implement the code stored in the computer-readable medium/memory <NUM>. The processor <NUM> includes circuitry <NUM> for transmitting (e.g., for transmitting, to a relay node, an indication to directly forward one or more TBs to one or more destination nodes, wherein directly forwarding includes transmitting a TB of the one or more TBs to the one or more destination nodes through only a PHY layer and a HARQ portion of a MAC layer in a protocol stack of the relay node) and code <NUM> for transmitting (e.g., for transmitting, to the relay node, control information for one or more data channels configuring one DL grant and two or more SL grants or two DL grants and one SL grant).

The method steps and/or actions may be interchanged with one another. In other words, unless a specific order of steps or actions is specified, the order and/or use of specific steps and/or actions may be modified.

Reference to an element in the singular is not intended to mean "one and only one" unless specifically so stated, but rather "one or more.

Combinations of the above can also be considered as computer-readable media.

For example, instructions for performing the operations described herein and illustrated in <FIG> and <FIG>.

Claim 1:
An apparatus (<NUM>) for wireless communication by a relay node (<NUM>), comprising:
a memory (<NUM>) storing computer-executable instructions (<NUM>, <NUM>, <NUM>, <NUM>); and
at least one processor (<NUM>) coupled to the memory, the at least one processor being configured to execute the computer-executable instructions and cause the apparatus to:
receive (<NUM>), from a source node (<NUM>), an indication to directly forward two or more transport blocks, TBs, to one or more destination nodes, wherein directly forwarding includes transmitting a TB of the two or more TBs to the one or more destination nodes (<NUM>, <NUM>) through only a Physical, PHY, layer and a hybrid automatic repeat request, HARQ, portion of a Media Access Control, MAC, layer in a protocol stack of the relay node;
receive (<NUM>), from the source node, control information for one or more data channels configuring two or more downlink, DL, grants, wherein the control information comprises an identification, ID, indicating a destination node, of the one or more destination nodes, to which the two or more TBs should be directly forwarded to;
receive two or more of the two or more TBs in accordance with the two or more DL grants, wherein each TB of the two or more received TBs comprises one MAC sub-protocol data unit, MAC sub-PDU, corresponding to a single Internet Protocol, IP, packet;
decode (<NUM>) the two or more received TBs based, at least in part, on the control information;
transmit, to the source node, hybrid automatic repeat request, HARQ, acknowledgement, ACK, feedback for the two or more received TBs;
receive, from the source node, additional control information configuring a sidelink, SL, grant that is based, at least in part, on a number of the two or more received TBs at the relay node;
concatenate the two or more received TBs in a concatenated TB; and
directly forward (<NUM>) the concatenated TB to the destination node based, at least in part, on the indication, the ID, and the SL grant.