CONTROL CHANNEL BASED ROUTING FOR MULTIPLE RELAY BASED COMMUNICATION

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a node may receive a first control channel associated with a multiple relay based communication. The node may identify a target node of a pay load of the first control channel based at least in part on at least one of: information included in the payload, or an identifier associated with the first control channel. The node may transmit a second control channel carrying the pay load toward the target node if the node is not the target node. The node may decode the payload, if the node is the target node. Numerous other aspects are described.

FIELD OF THE DISCLOSURE

Aspects of the present disclosure generally relate to wireless communication and to techniques and apparatuses for control channel based routing for multiple relay based communication.

BACKGROUND

SUMMARY

In some aspects, a method of wireless communication performed by a node includes receiving a first control channel associated with a multiple relay based communication; identifying a target node of a payload of the first control channel based at least in part on at least one of: information included in the payload, or an identifier associated with the first control channel; and transmitting a second control channel carrying the payload toward the target node if the node is not the target node; or decoding the payload, if the node is the target node.

In some aspects, a method of wireless communication performed by a base station includes generating a multiple relay based communication including a first control channel with a payload destined for a user equipment (UE); and transmitting, to a node, the first control channel, wherein the first control channel indicates a target node of a payload of the first control channel based at least in part on at least one of: information included in the payload, or an identifier associated with the first control channel.

In some aspects, a node includes one or more memories; and one or more processors, coupled to the one or more memories, configured to: receive a first control channel associated with a multiple relay based communication; identify a target node of a payload of the first control channel based at least in part on at least one of: information included in the payload, or an identifier associated with the first control channel; and transmit a second control channel carrying the payload toward the target node if the node is not the target node; or decode the payload, if the node is the target node.

In some aspects, a base station includes one or more memories; and one or more processors, coupled to the one or more memories, configured to: generate a multiple relay based communication including a first control channel with a payload destined for a UE; and transmit, to a node, the first control channel, wherein the first control channel indicates a target node of a payload of the first control channel based at least in part on at least one of: information included in the payload, or an identifier associated with the first control channel.

In some aspects, a non-transitory computer-readable medium storing a set of instructions includes one or more instructions that, when executed by one or more processors of a node, cause the node to: receive a first control channel associated with a multiple relay based communication; identify a target node of a payload of the first control channel based at least in part on at least one of: information included in the payload, or an identifier associated with the first control channel; and transmit a second control channel carrying the payload toward the target node if the node is not the target node; or decode the payload, if the node is the target node.

In some aspects, a non-transitory computer-readable medium storing a set of instructions includes one or more instructions that, when executed by one or more processors of a base station, cause the base station to: generate a multiple relay based communication including a first control channel with a payload destined for a UE; and transmit, to a node, the first control channel, wherein the first control channel indicates a target node of a payload of the first control channel based at least in part on at least one of: information included in the payload, or an identifier associated with the first control channel.

In some aspects, an apparatus includes means for receiving a first control channel associated with a multiple relay based communication; means for identifying a target node of a payload of the first control channel based at least in part on at least one of: information included in the payload, or an identifier associated with the first control channel; and means for transmitting a second control channel carrying the payload toward the target node if the apparatus is not the target node; or means for decoding the payload, if the node is the target node.

In some aspects, an apparatus includes means for generating a multiple relay based communication including a first control channel with a payload destined for a UE; and means for transmitting, to a node, the first control channel, wherein the first control channel indicates a target node of a payload of the first control channel based at least in part on at least one of: information included in the payload, or an identifier associated with the first control channel.

DETAILED DESCRIPTION

Wireless network100may also include relay stations, such as relay station110d. A relay station110dis an entity that can receive a transmission of data from an upstream station (e.g., a BS or a UE) and send a transmission of the data to a downstream station (e.g., a UE or a BS). A relay station110dmay also be a UE that can relay transmissions for other UEs. In the example shown inFIG.1, a relay station110dmay communicate with macro BS110aand a UE120din order to facilitate communication between BS110aand UE120d. A relay station110dmay also be referred to as a node, a relay node, a relay BS, a relay base station, a relay UE, a relay, or the like.

In some aspects, the node includes means for receiving a first control channel associated with a multiple relay based communication; means for identifying a target node of a payload of the first control channel based at least in part on at least one of: information included in the payload, or an identifier associated with the first control channel; or means for transmitting a second control channel carrying the payload toward the target node if the node is not the target node; or means for decoding the payload, if the node is the target node. In some aspects, the means for the node to perform operations described herein may include, for example, one or more of transmit processor220, TX MIMO processor230, modulator232, antenna234, demodulator232, MIMO detector236, receive processor238, controller/processor240, memory242, or scheduler246. In some aspects, the means for the node to perform operations described herein may include, for example, one or more of antenna252, demodulator254, MIMO detector256, receive processor258, transmit processor264, TX MIMO processor266, modulator254, controller/processor280, or memory282.

In some aspects, the base station includes means for generating a multiple relay based communication including a first control channel with a payload destined for a UE; and/or means for transmitting, to a node, the first control channel, wherein the first control channel indicates a target node of a payload of the first control channel based at least in part on at least one of: information included in the payload, or an identifier associated with the first control channel. The means for the base station to perform operations described herein may include, for example, one or more of transmit processor220, TX MIMO processor230, modulator232, antenna234, demodulator232, MIMO detector236, receive processor238, controller/processor240, memory242, or scheduler246.

FIG.3is a diagram illustrating an example300of multiple relay based communication, in accordance with the present disclosure.

As shown inFIG.3, a base station may communicate with UEs via relays. For example, there may be multiple links (depicted by dotted lines) between the base station, relays, and UEs. Communications (e.g., data and/or control information) between the base station and a UE may be transmitted via one or more of the relays. For example, as shown by reference number310, the base station may transmit a communication (e.g., via a payload included in a physical layer downlink control channel (PDCCH)) to Relay 1. As shown by reference number320, Relay 1 may relay (e.g., forward or transmit) the communication to UE 1. The sequence of hops followed by the PDCCH (in example300, BS to Relay 1 to UE 1) is referred to herein as a path or a link. In some contexts, “path” or “link” may indicate only hops between a BS and a relay. In other contexts, “path” or “link” indicates hops between a BS and a relay and between a relay and a UE.

The base station may control the transmission and retransmission of each relay and the content to be transmitted. To ensure the communications are forwarded, the base station may track the status of decoding payloads (e.g., transport blocks) at each relay. In a situation where a payload is decoded at a relay, the payload can be forwarded down-stream (e.g., to the destination UE). In a situation where a relay fails to decode a payload, the base station may schedule retransmission of the payload to the relay.

Using a relay (e.g., as shown inFIG.3) may improve network performance and increase reliability by providing link diversity for communications between a UE and base station. For example, the relays may be used to increase the coverage of the base station and also reduce the load of the base station. Furthermore, link diversity enables graceful handling of a failed link, such as due to a blockage associated with a beamformed communication.

While the use of a relay to relay communications between a base station and UE may improve network performance, traditionally, a direct communication between the relay and the base station is required to enable the base station to schedule the relay's downlink and uplink communications. This limits the use of relays to a single relay between the base station and the UE.

In some aspects described herein, a base station may generate a multiple relay based communication including a first control channel (e.g., a first PDCCH) with a payload destined for a UE. The first control channel may indicate a target node (e.g., a target relay node) of the payload based at least in part on information included in the payload (such as a UE identifier, a link identifier, one or more identifiers of relays, or the like), an identifier (e.g., a radio network temporary identifier (RNTI)) associated with the first control channel, or a combination thereof. The base station may transmit the first control channel to a node (e.g., a relay node). The node may receive the first control channel and identify a target node of the payload based at least in part on the information included in the payload, the identifier associated with the first control channel, or a combination thereof. The node may then transmit a second control channel (e.g., a second PDCCH) carrying the payload toward the target node, if the node is not the target node. If the node is the target node, the node may decode the payload.

In this way, some techniques and apparatuses described herein enable the use of multiple relays for communications between a base station and UE. This may improve network performance and increase reliability by providing link diversity for communications between a UE and base station. In addition, the use of multiple relays may increase an effective range and/or coverage of the base station, while also reducing the load of the base station. The use of control channel based routing may also conserve resources of the base station, including processing resources, time resources, memory resources, and/or power resources, among other examples, which may include resources that would otherwise be consumed by the base station to track the status of decoding at multiple nodes and/or schedule a node's downlink and uplink communications.

FIG.4is a diagram illustrating an example400associated with control channel based routing for multiple relay based communication, in accordance with the present disclosure. As shown inFIG.4, a base station (e.g., base station110) and multiple nodes (e.g., relay stations110d, UE120) may communicate with one another and with one or more UEs (e.g., UE120).

As shown by reference number410, the base station may transmit, and one or more nodes (e.g., relay 1, relay 2, and/or relay 3) and/or one or more UEs (e.g., UE 1 and/or UE 2) may receive, configuration information. In some aspects, a node and/or UE may receive the configuration information via one or more of radio resource control (RRC) signaling, MAC control elements (MAC CEs), downlink control information (DCI), a combination thereof, and/or the like. In some aspects, the configuration information may include an indication of one or more configuration parameters (e.g., already known to the node or UE) for selection by the node or UE, and/or explicit configuration information for the node or UE to use to configure the UE, among other examples. In some aspects, the configuration information may configure the node or UE, and/or enable the node or UE to configure itself, in a manner designed to enable control channel based routing for multiple relay based communication.

In some aspects, the configuration information may be associated with routing information. For example, the configuration information may configure (e.g., via RRC signaling) a mapping of one or more node identifiers (e.g., RNTI or a compressed form of identifier indicated by the configuration information) to a UE identifier (e.g., RNTI or a compressed form of identifier indicated by the configuration information) (e.g., in a situation where routing information for a PDCCH is to be included in a payload of the PDCCH).

In some aspects, the configuration information may indicate that a node is to pad a DCI payload of a PDCCH. For example, in a situation where a node receives a first PDCCH and is to generate a second PDCCH, the node may be configured to remove a destination identifier (e.g., a node identifier of the node) from the DCI payload of the first PDCCH and pad the DCI payload (such as using one or more filler bits) to a preconfigured length for transmission to a child node (e.g., a next target node) in the second PDCCH. Padding the DCI payload to the preconfigured length simplifies DCI processing for downstream nodes.

In some aspects, the configuration information may configure, for a node, node identifiers for each other node to which the node is connected. For example, in some situations, routing information for a PDCCH is carried in the payload of the PDCCH, and a link identifier (link ID) may be used in place of a node identifier (e.g., RNTI) to reduce the load of the PDCCH (each link ID identifying a route from the base station to each node). In such situations, the configuration information may preconfigure each node with RNTIs for each connected node, enabling the node to determine, using the link ID, which RNTI should be used to transmit the PDCCH to a next node. In some aspects, the configuration information indicates that the PDCCH is to include, in the link ID, the UE identifier (e.g., RNTI) of the destination UE. In this situation, the PDCCH would not need to include a separate UE identifier, as the UE identifier would be part of the link ID preconfigured for each route between the base station and the UE.

In some aspects, the configuration information may include information indicating a mapping between an identifier associated with a control channel and a child node of the node. A “child node” of a node is a node that is downstream from the node on a path. For example, if a communication is relayed from the BS, to Relay 1, then to Relay 2, Relay 2 is a child node of Relay 1. In some aspects, the mapping indicates an identifier for a control channel associated with routing the payload to the target node. For example, in a situation where an identifier (e.g., RNTI) is used to indicate routing information for a PDCCH, the base station may configure one or more nodes (e.g., via the configuration information) with a mapping from the identifier of an incoming PDCCH to the child node, and with the RNTI to be used for the outgoing PDCCH. In some aspects, the identifier for the control channel corresponds to a plurality of nodes, including a child node of the node, on a path to the target node. For example, an RNTI may correspond to multiple nodes, indicating a route to the target node and/or the destination UE. “Route” is synonymous with “path” as used herein.

By way of example, inFIG.4, the configuration information may indicate eleven RNTIs for relay 1: a self RNTI (e.g., RIC-RNTI) and five pairs. The five pairs may include a pair for relay 2 (e.g., R12-RNTI for incoming PDCCH, R2C-RNTI for outgoing PDCCH), a pair for UE 1 through relay 2 (e.g., R121-RNTI for incoming PDCCH, R21C-RNTI for outgoing PDCCH), a pair for UE 2 through relay 2 (e.g., R122-RNTI for incoming PDCCH, R22C-RNTI for outgoing PDCCH), a pair for relay 3 (e.g., R13-RNTI for incoming PDCCH, R3C-RNTI for outgoing PDCCH), a pair for UE 2 though relay 3 (e.g., R132-RNTI for incoming PDCCH, R32C-RNTI for outgoing PDCCH). In this example, relay 2 and relay 3 may each have five RNTIs configured via the configuration information, UE 1 may have one RNTI configured via the configuration information, and UE 2 may have 3 RNTIs configured via the configuration information.

In some aspects, the configuration information may indicate that a node is to be configured with an identifier (e.g., RNTI) for each route associated with that node. For example, in some aspects, all nodes on a route share the same RNTI for that route. By way of example, inFIG.4, the configuration information may indicate six RNTIs for relay 1: a first RNTI for the route from the base station to relay 1; a second RNTI for the route from the base station to relay 1, to relay 2; a third RNTI for the route from the base station to relay 1, to relay 2, and to UE 1; a fourth RNTI for the route from the base station to relay 1, to relay 2, and to UE 2; a fifth RNTI for the route from the base station to relay 1, to relay 3; and a sixth RNTI for the route from the base station to relay 1, to relay 3, to UE 2. In this example, three RNTIs may be configured for relay 2, four for relay 3, one for UE 1, and three for UE 2.

In some aspects, the configuration information may indicate that nodes monitoring the same node identifier (e.g., the same RNTI) are to be configured to avoid false detection. For example, nodes may be configured to use a different search space for transmission and reception of control information, time division multiplexing (TDM) for control information and/or payload transmission, and/or frequency division multiplexing (FDM) for control information and/or payload transmission, among other examples.

In some aspects, the configuration information may indicate that one or more of the nodes are to be configured for a first type of routing, and one or more other nodes are to be configured for a second type of routing. In some aspects, the identifier for a control channel corresponds to multiple nodes, including a child node of the node, on a path to a target node, and the identifier for the control channel is the same, irrespective of an upstream route of the control channel. For example, some nodes may be configured with a mapping of identifiers (e.g., RNTIs) of incoming PDCCH to a next node ID and the identifier (e.g., RNTI) to be used for an outgoing PDCCH. The nodes not configured in the foregoing manner may be configured using a shared identifier (e.g., a shared RNTI), such that an incoming PDCCH from different routes would share the same identifier. For example, the identifier for the control channel may be the same irrespective of an upstream route of the control channel.

By way of example, inFIG.4, the configuration information for relay 1 may indicate that relay 1 is to use a first type of routing (e.g., routing based at least in part on RNTIs), such as mapping a RNTI of an incoming PDCCH to a next node, or mapping the RNTI of the incoming PDCCH to a shared RNTI for a route to the target node (e.g., the prior to the destination UE). The configuration information may further indicate that relay 1, when generating the outgoing PDCCH, is to use a second type of routing (e.g., routing based at least in part on PDCCH payload), such as providing the target node ID (e.g., target node RNTI) in the PDCCH payload, providing the UE ID (e.g., UE RNTI) with the target node ID in the PDCCH payload, or adding a link ID to the PDCCH payload. In this situation, for example, relay 1 may be configured with three RNTIs, one for itself, one for a route to relay 2, and one for a route to relay 3; two RNTIs may be configured for relay 2 (e.g., one RNTI for itself, and another for the route from relay 1); and three RNTIs may be configured for relay 3 (e.g., one RNTI for itself, another for the route from relay 1, and another for the route from the base station to itself).

In some aspects, the configuration information may indicate that a node is to receive a grant for a resource associated with a second control channel, and the second control channel may be transmitted on the resource of the grant. For example, when a node generates an outgoing PDCCH, for an uplink reception, the PDCCH may carry information for an uplink grant DCI from a parent node to a child node. In some aspects, the uplink grant is dynamic. In other aspects, the uplink grant is a configured grant (e.g., configured based at least in part on the configuration information).

FIG.5Ais a diagram illustrating an example500associated with control channel based routing for multiple relay based communication, in accordance with the present disclosure. As shown inFIG.5A, a base station (e.g., base station110) and multiple nodes (e.g., relay stations110d, UE120) may communicate with one another and with one or more UEs (e.g., UE120).

As shown by reference number505, the base station may transmit, and the node (e.g., relay 1) may receive, a first control channel (e.g., PDCCH) associated with a multiple relay based communication. In some aspects, the information included in the payload includes a node identifier of one or more nodes on a path between a source of the payload and the target node. For example, the PDCCH depicted by reference number505includes data identifying UE ID (e.g., RNTI of UE 1) and at least one Node ID (e.g., RNTIs of nodes along the path from the base station to the target UE). As used herein, the target node may be a UE or a relay.

In some aspects, configuration information, provided by the base station, may indicate that the node identifier, included in the payload, is configured as associated with the path between the source of the payload and the target node or the one or more nodes. For example, the nodes on the path may be represented by individual node identifiers, such that three node identifiers may be included for each of three nodes along the path. Additionally, or alternatively, node IDs and/or UE IDs may be compressed in accordance with the configuration information, enabling the identifiers to be stored in the payload in a compressed format.

The node may identify a target node of a payload of the first control channel based at least in part on information included in the payload, and/or an identifier associated with the first control channel. In some aspects, the node may remove the node identifier from the payload for transmission of the payload via a second control channel (e.g., a second PDCCH). In this situation, the node may pad the payload (e.g., using zero-padding or another padding method) to satisfy a DCI length threshold. The node may further add, to the payload, an update node identifier for transmission via the second control channel. In some aspects, the node may remove a destination field, which includes the node identifier, from the payload for transmission via the second control channel, without padding the payload. In this situation, each node may need to be configured (e.g., via configuration information) to support varied DCI lengths.

As shown by reference number510, the node may transmit a second control channel carrying the payload toward the target node if the node is not the target node. By way of example, the PDCCH generated by relay 1 for transmission to relay 2 may use different node IDs in the payload of the PDCCH (e.g., removing the RNTI of relay 1 from the payload), and the cyclic redundancy check portion of the PDCCH may be masked by the RNTI of the next node, relay 2.

Alternatively, if the node is the target node, the node may decode the payload. For example, as shown by reference number515, relay 2 may be the target node. In this situation, when relay 2 receives the PDCCH from relay 1, relay 2 may decode and use the payload itself.

In some aspects, the base station may transmit, and the node may receive, a grant for a resource associated with the second control channel, and the second control channel may be transmitted on the resource of the grant. For example, for a downlink transmission, the PDCCH carries information regarding the downlink grant in a DCI. The node may transmit the downlink grant using information from the PDCCH. For an uplink reception, the PDCCH carries information for an uplink grant DCI from parent node to child node. The node may send an uplink grant using information from the PDCCH. In some aspects, the grant can be a dynamic grant. In some aspects, the grant can be a configured grant.

As indicated above,FIG.5Ais provided as an example. Other examples may differ from what is described with regard toFIG.5A.

FIG.5Bis a diagram illustrating an example520associated with control channel based routing for multiple relay based communication, in accordance with the present disclosure. As shown inFIG.5B, a base station (e.g., base station110) and multiple nodes (e.g., relay stations110d) may communicate with one another and with one or more UEs (e.g., UE120). Some parts of example520shown inFIG.5Bare similar to example500ofFIG.5A. Therefore, the description ofFIG.5Bfocuses on some differences between examples500and520(though examples500and520may differ from each other in ways not explicitly described here).

As shown by reference number525, in some aspects, the information included in the payload (e.g., of the first PDCCH) includes a UE identifier of a UE associated with the payload (e.g., an RNTI of the destination UE) and a link ID of a path between a source of the payload and the target node. For example, rather than including, in the control channel payload, separate node identifiers for each of the nodes along a path from the base station to the destination UE, a link ID may be used. The link ID identifies the route from the base station to the target relay and may reduce a load of the first control channel, relative to including multiple node identifiers in the payload. For example, each node's RNTI may take 16 bits to represent, and a single link ID (e.g., also 16 bits) may be used to represent a path, obviating the need to include multiple node RNTIs in the PDCCH payload.

By way of example, inFIG.5B, rather than including RNTIs for each relay along the path from the base station, to relay 1, to relay 2, and to UE 1, one of four link IDs may be selected (e.g., by the base station) to be included in the payload of the PDCCH. For example, one link ID may represent the path from the base station to relay 1, another link ID may represent the path from the base station to relay 3, another link ID may represent the path from the base station to relay 2 through relay 1, and another link ID may represent the path from the base station to relay 3 through relay 1.

As shown by reference number530, the node (e.g., relay 1) may transmit the second control channel (e.g., the second PDCCH) with an identifier of a next node on the path (e.g., relay 2) based at least in part on the link identifier. For example, the link ID for example520may identify the path as going from the base station to relay 1 and then to relay 2.

As indicated above,FIG.5Bis provided as an example. Other examples may differ from what is described with regard toFIG.5B.

FIG.5Cis a diagram illustrating an example535associated with control channel based routing for multiple relay based communication, in accordance with the present disclosure. As shown inFIG.5C, a base station (e.g., base station110) and multiple nodes (e.g., relay stations110d) may communicate with one another and with one or more UEs (e.g., UE120). Example535shown inFIG.5Cmay be similar to example520ofFIG.5B; therefore, the description ofFIG.5Cfocuses on differences between examples520and535.

As shown by reference number540, in some aspects, the information included in the payload (e.g., of the first PDCCH) includes a link ID of a path between a source of the payload and a UE, or other node, that is the destination of the payload. For example, a link ID may be included in the payload, rather than separate node identifiers for each of the nodes along a path from the base station to the destination UE or node and a UE or node identifier. The link ID identifies the route from the base station to the destination UE or node. Including the link ID may reduce a load of the first control channel relative to including multiple node identifiers and the UE ID or node ID. For example, RNTIs (e.g., used as node IDs and UE ID) may take 16 bits each to represent, and a single link ID (e.g., also 16 bits) may be used to represent a path, obviating the need to include multiple node RNTIs and the UE RNTI in the PDCCH payload.

By way of example, inFIG.5C, rather than including RNTIs for each relay and destination node or UE along the path from the base station, to relay 1, to relay 2, and to UE 1, a link ID may be selected (e.g., by the base station) to be included in the payload of the PDCCH. For example, one link ID may be used to represent the path from the base station through relay 1, relay 2, and UE 1.

As shown by reference number545, the node (e.g., relay 1) may transmit the second control channel (e.g., the second PDCCH) with an identifier of a next node on the path (e.g., relay 2) based at least in part on the link ID. For example, the link ID for example535may identify the path as going from the base station to relay 1, then to relay 2, and then to UE 1.

As indicated above,FIG.5Cis provided as an example. Other examples may differ from what is described with regard toFIG.5C.

FIG.6is a diagram illustrating an example600associated with control channel based routing for multiple relay based communication, in accordance with the present disclosure. As shown inFIG.6, a base station (e.g., base station110) and multiple nodes (e.g., relay stations110d) may communicate with one another and with one or more UEs (e.g., UE120). Some parts of example600are similar to example500ofFIG.5A. Therefore, the description ofFIG.6focuses on some differences between examples500and600(though examples500and600may differ from each other in ways not explicitly described here).

In some aspects, each node may be configured (e.g., by the base station) with a mapping between an identifier associated with a first control channel (e.g., first PDCCH) and a child node of the node (or the node itself). In some aspects, the mapping indicates an identifier for a second control channel (e.g., second PDCCH) associated with routing the payload to the target node. For example, in a situation where an identifier (e.g., RNTI) is used to indicate routing information for a PDCCH, the base station may configure each node (e.g., via the configuration information) with a mapping from an RNTI of an incoming PDCCH to the child node, and the RNTI to be used for the outgoing PDCCH. In some aspects, the identifier for the control channel corresponds to a plurality of nodes, including a child node of the node, on a path to the target node. For example, an RNTI may correspond to multiple nodes, indicating a route to the target node and/or the destination UE.

As shown by reference number605, the base station transmits a first PDCCH to relay 1. The routing information may be indicated by an RNTI used to mask the cyclic redundancy check (CRC) of the first PDCCH, and by a mapping for relay 1.

By way of example, inFIG.6, the mapping for relay 1 may include routing information for eleven RNTIs: a self RNTI (e.g., RIC-RNTI) and five pairs: a pair for relay 2 (e.g., R12-RNTI for incoming PDCCH, R2C-RNTI for outgoing PDCCH), a pair for UE 1 through relay 2 (e.g., R121-RNTI for incoming PDCCH, R21C-RNTI for outgoing PDCCH), a pair for UE 2 through relay 2 (e.g., R122-RNTI for incoming PDCCH, R22C-RNTI for outgoing PDCCH), a pair for relay 3 (e.g., R13-RNTI for incoming PDCCH, R3C-RNTI for outgoing PDCCH), a pair for UE 2 though relay 3 (e.g., R132-RNTI for incoming PDCCH, R32C-RNTI for outgoing PDCCH). In this example, relay 2 and relay 3 may each have five RNTIs configured via the configuration information, UE 1 may have one RNTI configured via the configuration information, and UE 2 may have 3 RNTIs configured via the configuration information.

In some aspects, the identifier associated with the first control channel is associated with each node on a path between the source of the payload and the target node or target UE. For example, in some aspects, all nodes on a route may share the same RNTI for that route. In some aspects, the RNTI for the route may include the destination UE. By way of example, inFIG.6, the mapping for relay 1 may include routing information for six RNTIs for relay 1: a first RNTI for the route from the base station to relay 1; a second RNTI for the route from the base station to relay 1, to relay 2; a third RNTI for the route from the base station to relay 1, to relay 2, and to UE 1; a fourth RNTI for the route from the base station to relay 1, to relay 2, and to UE 2; a fifth RNTI for the route from the base station to relay 1, to relay 3; and a sixth RNTI for the route from the base station to relay 1, to relay 3, to UE 2. In this example, three RNTIs may be configured for relay 2, four for relay 3, one for UE 1, and three for UE 2.

As shown by reference number610, the second PDCCH may be transmitted to a child node of the node on a path to the target node based at least in part on the mapping between the RNTI indicated by the first PDCCH and the child node (e.g., relay 2). For example, relay 1 may use the route RNTI and a previously configured mapping to determine to route the communication to relay 2.

In some aspects, the node may transmit the second control channel using a differentiation technique, such that a recipient node can determine whether the second control channel is destined for the recipient node. For example, in a situation where all nodes on a route share the same RNTI, nodes receiving a PDCCH may use a differentiation technique (e.g., using a different search space, TDM, and/or FDM, among other examples) to enable the node to determine if the PDCCH is destined for that node or is to be forwarded in accordance with the mapping.

As indicated above,FIG.7Ais provided as an example. Other examples may differ from what is described with regard toFIG.7A. As shown inFIG.7A, a base station (e.g., base station110) and multiple nodes (e.g., relay stations110d) may communicate with one another and with one or more UEs (e.g., UE120). Some parts of example700shown inFIG.7Amay be similar to one or more of examples500,520,535, and600ofFIGS.5A,5B,5C, and6, respectively. Therefore, the description ofFIG.7Adescribes differences between examples500,520,535,600, and700(though other differences may arise that are not explicitly described).

In some aspects, one or more of the nodes are to be configured for a first type of routing, and one or more other nodes are to be configured for a second type of routing. In some aspects, the identifier for a control channel may correspond to multiple nodes, including a child node of the node, on a path to a target node, and the identifier for the control channel may be the same, irrespective of an upstream route of the control channel. For example, some nodes may be configured with a mapping of identifiers (e.g., RNTIs) of an incoming PDCCH to a next node ID and the identifier (e.g., RNTI) to be used for an outgoing PDCCH. The nodes not configured in the foregoing manner may be configured using a shared identifier (e.g., a shared RNTI), such that an incoming PDCCH from different routes would share the same identifier. In some aspects, one or more identifiers (e.g., node IDs, link IDs, and/or destination UE IDs) may be included in the PDCCH payload.

As shown by reference number705,FIG.7provides three example options for the first PDCCH transmitted from the base station to relay 1. The first option, as shown by reference number710, may be considered a combination of parts of example500described with respect toFIG.5Aand example600described with respect toFIG.6. For example, the first PDCCH payload includes a UE ID (e.g., UE RNTI) for a destination UE (e.g., UE 1), and one or more node IDs (e.g., node RNTIs) to which the PDCCH is to be routed. The first PDCCH also includes a CRC masked by either an RNTI for a route or the next target node's RNTI. For example, the CRC may be masked by an RNTI for relay 2 or an RNTI for a route from the base station through relay 1 and relay 2. A mapping for relay 1 indicates the RNTI to be used for the second (e.g., outgoing) PDCCH, and in some aspects, the other relays (e.g., relay 2) may be configured with a shared RNTI.

The second option, as shown by reference number715, may be considered a combination of parts of example520described with respect toFIG.5Band example600described with respect toFIG.6. For example, the first PDCCH payload includes a UE ID (e.g., UE RNTI) for a destination UE (e.g., UE 1) and a link ID indicating a route to the last relay (e.g., relay 2) to which the PDCCH is to be routed. The first PDCCH also includes a CRC masked by either an RNTI for a route or the next target node's RNTI. For example, the CRC may be masked by an RNTI for relay 2 or an RNTI for a route from the base station through relay 1 and relay 2.

The third option, as shown by reference number720, may be considered a combination of example535described with respect toFIG.5Cand example600described with respect toFIG.6. For example, the first PDCCH payload includes a link ID indicating a route to the destination UE (e.g., UE 1) to which the PDCCH is to be routed. The first PDCCH also includes a CRC masked by either an RNTI for a route or the next target node's RNTI. For example, the CRC may be masked by an RNTI for relay 2 or an RNTI for a route from the base station through relay 1 and relay 2.

As shown by reference number725, in some aspects, when relay 1 routes the second PDCCH to relay 2, the payload may stay the same, though the CRC may be masked by the RNTI for relay 2, enabling relay 2 to decode the second PDCCH and determine the destination UE based at least in part on the payload of the second PDCCH (e.g., as in the second PDCCH of any ofFIGS.5A-5C).

In some aspects, a node which directly connects with another type of node may have three types of RNTI: an RNTI for itself, an RNTI for the other type of node (e.g., child node RNTI), and different RNTIs to target different relays (e.g., route RNTIs). In this way, the number of RNTIs needed may be reduced in various circumstances.

FIG.7Bis a diagram illustrating an example730associated with control channel based routing for multiple relay based communication, in accordance with the present disclosure. As shown inFIG.7B, a base station (e.g., base station110) and multiple nodes (e.g., relay stations110d) may communicate with one another and with one or more UEs (e.g., UE120). Example730shown inFIG.7Bmay be similar to example700ofFIG.7A; therefore, the description ofFIG.7Bdescribes some differences between examples700and730.

In some aspects, a route RNTI (e.g., as described above with reference toFIG.6) may be combined with a UE identifier included in a payload of a control channel (e.g., as described above with reference toFIGS.5A and5B). For example, a base station may configure a route to reach each target node (e.g., a target node being the last node prior to a UE for downlink communication), and each node of the route may share the same identifier (e.g., a route RNTI). In this way, a shared route RNTI may be used to route a PDCCH to a target node, and the target node may use the UE ID of the payload to route the PDCCH to the destination UE.

As shown by reference number735, the first PDCCH is similar to example520described with respect toFIG.5Band example600described with respect toFIG.6. For example, the first PDCCH payload includes a UE ID (e.g., UE RNTI) for a destination UE (e.g., UE 1), but no node IDs or link IDs are included in the payload. The CRC of the first PDCCH is masked by an RNTI for a route. For example, the CRC may be masked by an RNTI for a route from the base station through relay 1 and to relay 2.

As shown by reference number740, the second PDCCH includes the same data included in the first PDCCH (e.g., the UE ID in the payload of the second PDCCH) and the route RNTI masking the CRC. In this situation, relay 2 may use a differentiation technique (e.g., different search space, TDM, and/or FDM, among other examples) to determine whether the second PDCCH is for relay 2. After determining that the second PDCCH is for relay 2, relay 2 may extract the UE ID from the payload of the second PDCCH and the payload may then be transmitted to the destination UE (e.g., UE 1).

In this situation, three RNTIs may be configured for relay 1: an RNTI for itself, a second RNTI for the route traversing relay 1 and relay 2, and a third RNTI for the route traversing relay 1 and relay 3. In this example, relay 2 may use two RNTIs (e.g., an RNTI for itself and another RNTI for the route traversing relay 1 to relay 2), relay 3 may use 3 RNTIs (e.g., an RNTI for itself, another RNTI for the route traversing relay 1 to relay 3, and another RNTI for itself as the target node before the destination UE).

As indicated above,FIG.7Bis provided as an example. Other examples may differ from what is described with regard toFIG.7B.

While the foregoing examples are presented in the context of downlink communications via multiple relays, the same techniques may be applied for uplink and/or sidelink communications via multiple relays.

In this way, some techniques and apparatuses described herein enable the use of multiple relays for communications between a base station and UE. This may improve network performance and increase reliability by providing link diversity for communications between a UE and base station. In addition, the use of multiple relays may be used to increase an effective range and/or coverage of the base station, while also reducing the load of the base station. The use of control channel based routing may also conserve resources of the base station, including processing resources, time resources, memory resources, and/or power resources, among other examples, which may include resources that would otherwise be consumed by the base station to track the status of decoding at multiple node and/or schedule a node's downlink and uplink communications.

FIG.8is a diagram illustrating an example process800performed, for example, by a node, in accordance with the present disclosure. Example process800is an example where the node (e.g., relay station110d, UE120, BS110) performs operations associated with control channel based routing for multiple relay based communication.

As shown inFIG.8, in some aspects, process800may include receiving a first control channel associated with a multiple relay based communication (block810). For example, the node (e.g., using reception component1002, depicted inFIG.10) may receive a first control channel associated with a multiple relay based communication, as described above.

As further shown inFIG.8, in some aspects, process800may include identifying a target node of a payload of the first control channel based at least in part on at least one of: information included in the payload, or an identifier associated with the first control channel (block820). For example, the node (e.g., using identification component1008, depicted inFIG.10) may identify a target node of a payload of the first control channel based at least in part on at least one of: information included in the payload, or an identifier associated with the first control channel, as described above.

As further shown inFIG.8, in some aspects, process800may include transmitting a second control channel carrying the payload toward the target node if the node is not the target node (block830). For example, the node (e.g., using transmission component1004, depicted inFIG.10) may transmit a second control channel carrying the payload toward the target node if the node is not the target node, as described above.

As further shown inFIG.8, in some aspects, process800may include decoding the payload, if the node is the target node (block840). For example, the node (e.g., using decoding component1010, depicted inFIG.10) may decode the payload, if the node is the target node, as described above.

In a first aspect, process800includes receiving a grant for a resource associated with the second control channel, wherein the second control channel is transmitted on the resource of the grant.

In a second aspect, the grant is one of a dynamic grant, or a configured grant.

In a third aspect, process800includes receiving information indicating a downlink control information (DCI) type of the first control channel, wherein receiving the first control channel is based at least in part on the DCI type.

In a fourth aspect, the information included in the payload is a node identifier of one or more nodes on a path between a source of the payload and the target node.

In a fifth aspect, the node identifier is configured as associated with the path or the one or more nodes.

In a sixth aspect, process800includes removing a destination field that includes the node identifier from the payload for transmission via the second control channel, and adding, to the payload, an updated node identifier for transmission via the second control channel.

In a seventh aspect, process800includes removing the node identifier from the payload for transmission via the second control channel, padding the payload to satisfy a downlink control information length threshold, and adding, to the payload, an updated node identifier for transmission via the second control channel.

In an eighth aspect, the information included in the payload includes a UE identifier of a UE associated with the payload and a link identifier of a path between a source of the payload and the target node.

In a ninth aspect, transmitting the second control channel further comprises transmitting the second control channel with an identifier of a next node on the path based at least in part on the link identifier.

In a tenth aspect, the information included in the payload is a link identifier of a path between a source of the payload and a user equipment that is a destination of the payload.

In an eleventh aspect, the identifier associated with the first control channel is a radio network temporary identifier.

In a twelfth aspect, transmitting the second control channel toward the target node further comprises transmitting the second control channel to a child node of the node on a path to the target node based at least in part on a mapping between the identifier associated with the first control channel and the child node.

In a thirteenth aspect, the mapping indicates an identifier for the second control channel associated with routing the payload to the target node.

In a fourteenth aspect, the identifier for the second control channel corresponds to a plurality of nodes, including the child node, on the path to the target node, and the identifier for the second control channel is the same irrespective of an upstream route of the second control channel.

In a fifteenth aspect, transmitting the second control channel to a child node on a path to the target node is based at least in part on an identifier of the child node or an identifier of the path associated with the first control channel.

In a sixteenth aspect, the identifier associated with the first control channel is associated with each node of a plurality of nodes on a path between a source of the payload and the target node.

In a seventeenth aspect, transmitting the second control channel further comprises transmitting the second control channel using a differentiation technique such that a recipient node of the plurality of nodes can determine whether the second control channel is destined for the recipient node.

In an eighteenth aspect, the identifier associated with the first control channel is associated with a UE for which the payload is destined.

In a nineteenth aspect, the target node is a last node on the path before a UE and the payload includes an identifier of the UE.

FIG.9is a diagram illustrating an example process900performed, for example, by a base station, in accordance with the present disclosure. Example process900is an example where the base station (e.g., base station110) performs operations associated with control channel based routing for multiple relay based communication.

As shown inFIG.9, in some aspects, process900may include generating a multiple relay based communication including a first control channel with a payload destined for a UE (block910). For example, the base station (e.g., using communication component1108, depicted inFIG.11) may generate a multiple relay based communication including a first control channel with a payload destined for a UE, as described above.

As further shown inFIG.9, in some aspects, process900may include transmitting, to a node, the first control channel, wherein the first control channel indicates a target node of a payload of the first control channel based at least in part on at least one of: information included in the payload, or an identifier associated with the first control channel (block920). For example, the base station (e.g., using transmission component1104, depicted inFIG.11) may transmit, to a node, the first control channel, wherein the first control channel indicates a target node of a payload of the first control channel based at least in part on at least one of: information included in the payload, or an identifier associated with the first control channel, as described above.

In a first aspect, process900includes transmitting a grant for a resource associated with a second control channel via which the payload is to be transmitted to a child node of the node.

In a second aspect, the grant is one of a dynamic grant, or a configured grant.

In a third aspect, process900includes transmitting information indicating a DCI type of the first control channel.

In a fourth aspect, the information included in the payload is a node identifier of one or more nodes on a path between a source of the payload and the target node.

In a fifth aspect, the node identifier is configured as associated with the path or the one or more nodes.

In a sixth aspect, the information included in the payload is a UE identifier of the UE or a link identifier of a path between a source of the payload and the target node.

In a seventh aspect, the information included in the payload is a link identifier of a path between a source of the payload and the UE.

In an eighth aspect, the identifier associated with the first control channel is a radio network temporary identifier.

In a ninth aspect, process900includes configuring, for the node, a mapping between the identifier associated with the first control channel and a child node of the node.

In a tenth aspect, the mapping indicates an identifier for a control channel associated with routing the payload to the target node.

In an eleventh aspect, the identifier for the control channel corresponds to a plurality of nodes, including a child node of the node, on a path to the target node, and the identifier for the control channel is the same irrespective of an upstream route of the control channel.

In a twelfth aspect, routing of the payload on a path to the target node is based at least in part on an identifier of the child node or an identifier of the path associated with the first control channel.

In a thirteenth aspect, the identifier associated with the first control channel is associated with each node of a plurality of nodes on a path between the base station and the target node.

In a fourteenth aspect, the identifier associated with the first control channel is associated with the UE to which the payload is destined.

In a fifteenth aspect, the target node is a last node on the path before the UE and the payload includes an identifier of the UE.

FIG.10is a block diagram of an example apparatus1000for wireless communication. The apparatus1000may be a node, or a node may include the apparatus1000. In some aspects, the apparatus1000includes a reception component1002and a transmission component1004, which may be in communication with one another (for example, via one or more buses and/or one or more other components). As shown, the apparatus1000may communicate with another apparatus1006(such as a UE, a base station, or another wireless communication device) using the reception component1002and the transmission component1004. As further shown, the apparatus1000may include one or more of an identification component1008, a decoding component1010, or a payload processing component1012, among other examples.

The reception component1002may receive a first control channel associated with a multiple relay based communication. The identification component1008may identify a target node of a payload of the first control channel based at least in part on at least one of information included in the payload, or an identifier associated with the first control channel. The transmission component1004may transmit a second control channel carrying the payload toward the target node if the node is not the target node. The decoding component1010may decode the payload, if the node is the target node.

The reception component1002may receive a grant for a resource associated with the second control channel, wherein the second control channel is transmitted on the resource of the grant.

The reception component1002may receive information indicating a DCI type of the first control channel, wherein receiving the first control channel is based at least in part on the DCI type.

The payload processing component1012may remove a destination field that includes the node identifier from the payload for transmission via the second control channel.

The payload processing component1012may add, to the payload, an updated node identifier for transmission via the second control channel.

The payload processing component1012may remove the node identifier from the payload for transmission via the second control channel.

The payload processing component1012may pad the payload to satisfy a downlink control information length threshold.

The payload processing component1012may add, to the payload, an updated node identifier for transmission via the second control channel.

FIG.11is a block diagram of an example apparatus1100for wireless communication. The apparatus1100may be a base station, or a base station may include the apparatus1100. In some aspects, the apparatus1100includes a reception component1102and a transmission component1104, which may be in communication with one another (for example, via one or more buses and/or one or more other components). As shown, the apparatus1100may communicate with another apparatus1106(such as a UE, a base station, or another wireless communication device) using the reception component1102and the transmission component1104. As further shown, the apparatus1100may include one or more of a communication component1108or a configuration component1110, among other examples.

The communication component1108may generate a multiple relay based communication including a first control channel with a payload destined for a UE. The transmission component1104may transmit, to a node, the first control channel, wherein the first control channel indicates a target node of a payload of the first control channel based at least in part on at least one of information included in the payload, or an identifier associated with the first control channel.

The transmission component1104may transmit a grant for a resource associated with a second control channel via which the payload is to be transmitted to a child node of the node.

The transmission component1104may transmit information indicating a downlink control information type of the first control channel.

The configuration component1110may configure, for the node, a mapping between the identifier associated with the first control channel and a child node of the node.

Aspect 1: A method of wireless communication performed by a node, comprising: receiving a first control channel associated with a multiple relay based communication; identifying a target node of a payload of the first control channel based at least in part on at least one of: information included in the payload, or an identifier associated with the first control channel; and transmitting a second control channel carrying the payload toward the target node if the node is not the target node; or decoding the payload, if the node is the target node.

Aspect 2: The method of Aspect 1, further comprising: receiving a grant for a resource associated with the second control channel, wherein the second control channel is transmitted on the resource of the grant.

Aspect 3: The method of Aspect 2, wherein the grant is one of: a dynamic grant, or a configured grant.

Aspect 4: The method of any of Aspects 1-3, further comprising: receiving information indicating a downlink control information (DCI) type of the first control channel, wherein receiving the first control channel is based at least in part on the DCI type.

Aspect 5: The method of any of Aspects 1-4, wherein the information included in the payload is a node identifier of one or more nodes on a path between a source of the payload and the target node.

Aspect 6: The method of Aspect 5, wherein the node identifier is configured as associated with the path or the one or more nodes.

Aspect 7: The method of Aspect 5, further comprising: removing a destination field that includes the node identifier from the payload for transmission via the second control channel; and adding, to the payload, an updated node identifier for transmission via the second control channel.

Aspect 8: The method of Aspect 5, further comprising: removing the node identifier from the payload for transmission via the second control channel; padding the payload to satisfy a downlink control information length threshold; and adding, to the payload, an updated node identifier for transmission via the second control channel.

Aspect 9: The method of any of Aspects 1-4, wherein the information included in the payload includes a user equipment (UE) identifier of a UE associated with the payload and a link identifier of a path between a source of the payload and the target node.

Aspect 10: The method of Aspect 9, wherein transmitting the second control channel further comprises: transmitting the second control channel with an identifier of a next node on the path based at least in part on the link identifier.

Aspect 11: The method of any of Aspects 1-10, wherein the information included in the payload is a link identifier of a path between a source of the payload and a user equipment that is a destination of the payload.

Aspect 12: The method of any of Aspects 1-11, wherein the identifier associated with the first control channel is a radio network temporary identifier.

Aspect 13: The method of Aspect 12, wherein transmitting the second control channel toward the target node further comprises: transmitting the second control channel to a child node of the node on a path to the target node based at least in part on a mapping between the identifier associated with the first control channel and the child node.

Aspect 14: The method of Aspect 13, wherein the mapping indicates an identifier for the second control channel associated with routing the payload to the target node.

Aspect 15: The method of Aspect 14, wherein the identifier for the second control channel corresponds to a plurality of nodes, including the child node, on the path to the target node, and wherein the identifier for the second control channel is the same irrespective of an upstream route of the second control channel.

Aspect 16: The method of Aspect 14, wherein transmitting the second control channel to a child node on a path to the target node is based at least in part on an identifier of the child node or an identifier of the path associated with the first control channel.

Aspect 17: The method of any of Aspects 1-16, wherein the identifier associated with the first control channel is associated with each node of a plurality of nodes on a path between a source of the payload and the target node.

Aspect 18: The method of Aspect 17, wherein transmitting the second control channel further comprises: transmitting the second control channel using a differentiation technique such that a recipient node of the plurality of nodes can determine whether the second control channel is destined for the recipient node.

Aspect 19: The method of Aspect 17, wherein the identifier associated with the first control channel is associated with a user equipment for which the payload is destined.

Aspect 20: The method of Aspect 17, wherein the target node is a last node on the path before a user equipment and wherein the payload includes an identifier of the user equipment.

Aspect 21: A method of wireless communication performed by a base station, comprising: generating a multiple relay based communication including a first control channel with a payload destined for a user equipment (UE); and transmitting, to a node, the first control channel, wherein the first control channel indicates a target node of a payload of the first control channel based at least in part on at least one of: information included in the payload, or an identifier associated with the first control channel.

Aspect 22: The method of Aspect 21, further comprising: transmitting a grant for a resource associated with a second control channel via which the payload is to be transmitted to a child node of the node.

Aspect 23: The method of Aspect 22, wherein the grant is one of: a dynamic grant, or a configured grant.

Aspect 24: The method of any of Aspects 21-23, further comprising: transmitting information indicating a downlink control information type of the first control channel.

Aspect 25: The method of any of Aspects 21-24, wherein the information included in the payload is a node identifier of one or more nodes on a path between a source of the payload and the target node.

Aspect 26: The method of Aspect 25, wherein the node identifier is configured as associated with the path or the one or more nodes.

Aspect 27: The method of any of Aspects 21-24, wherein the information included in the payload is a UE identifier of the UE or a link identifier of a path between a source of the payload and the target node.

Aspect 28: The method of any of Aspects 21-24, wherein the information included in the payload is a link identifier of a path between a source of the payload and the UE.

Aspect 29: The method of any of Aspects 21-28, wherein the identifier associated with the first control channel is a radio network temporary identifier.

Aspect 30: The method of any of Aspects 21-29, further comprising: configuring, for the node, a mapping between the identifier associated with the first control channel and a child node of the node.

Aspect 31: The method of Aspect 30, wherein the mapping indicates an identifier for a control channel associated with routing the payload to the target node.

Aspect 32: The method of Aspect 31, wherein the identifier for the control channel corresponds to a plurality of nodes, including a child node of the node, on a path to the target node, and wherein the identifier for the control channel is the same irrespective of an upstream route of the control channel.

Aspect 33: The method of Aspect 31, wherein routing of the payload on a path to the target node is based at least in part on an identifier of the child node or an identifier of the path associated with the first control channel.

Aspect 34: The method of any of Aspects 21-32, wherein the identifier associated with the first control channel is associated with each node of a plurality of nodes on a path between the base station and the target node.

Aspect 35: The method of Aspect 34, wherein the identifier associated with the first control channel is associated with the UE to which the payload is destined.

Aspect 36: The method of Aspect 34, wherein the target node is a last node on the path before the UE and wherein the payload includes an identifier of the UE.