TW202308415A - Methods and user equipment for wireless communication - Google Patents

Abstract

A method for wireless communication, comprising: receiving a recommended bit rate query message from a remote UE, wherein the message is carried by a control signaling or by a sidelink MAC control element (SL MAC CE) dedicated for the remote UE; forwarding the recommended bit rate query message to a base station over Layer-2 sidelink relay when the message is carried by the control signaling; and forwarding the recommended bit rate query message to the base station when the message is carried by the SL MAC CE, wherein the SL MAC CE has a unique SL logical channel ID (SL LCID) value that indicates the recommended bit rate query message.

Description

Method and user equipment for wireless communication

The present invention is related to wireless network communication, especially refers to the UE-to-network relay (UE- to-Network Relay) to realize the end-to-end (end-to-end) media storage between the remote user equipment (User Equipment, UE) (remote UE) and the next generation Node B (next generation Node B, gNB) Take control (Media Access Control, MAC) control unit (Control Element, CE) transmission.

New technologies in 5G NR allow cellular devices to connect directly to each other using a technique called SideLink (SL) communication. Sidelink is a new communication paradigm in which cellular devices are able to communicate without relaying their data through the network. The sidelink interface may also be referred to as the PC5 interface. Various applications can rely on the communication on the sidelink interface, such as Vehicle-to-everything (V2X) communication, Public Safety (PS) communication, direct file transfer between user devices, etc. To support sidelink relay, there are two UE-to-Network relay architectures, namely, Layer 2 (Layer 2, L2) relay and Layer 3 (Layer 3, L3) relay.

In the case of L3-based sidelink relay, the relay UE acts as a general router in the data communication network and forwards the data packet flow of the remote UE as an Internet Protocol (IP) service. ). Forwarding of IP-based services is performed in a best-effort manner. For L3 UE to network relay, there are both Sidelink Radio Bearer (SLRB) and Uu radio bearer on PC5 to carry between the remote UE and the 5G core (5G Core, 5GC) Established Quality of Service (QoS) flow. L3 UE-to-network relays can support flow-based mapping at the Service Data Adaptation Protocol (SDAP) layer when converting PC5 flows to Uu flows during traffic forwarding, and vice versa. Please note that since the L3-based sidelink relay UE works like an IP router, the remote UE is transparent to the gNB, that is, the gNB cannot know that the traffic transmitted by the relay UE originates from the relay UE itself, Also originated from the remote UE but forwarded by the relay UE.

In contrast, in the case of L2-based SL relay, the relay is performed above the Radio Link Control (RLC) sublayer via the relay UE for the control plane between the remote UE and the network ( Control Plane, CP) and User Plane (User Plane, UP). Uu SDAP/packet data convergence protocol (Packet Data Convergence Protocol, PDCP) and radio resource control (Radio Resource Control, RRC) are terminated between the remote UE and gNB, while the RLC, MAC and physical (Physical, PHY) layers are The link between the remote UE and the UE to the network relay UE and the link between the UE and the network relay UE to the gNB). Uu supports the adaptation layer on the RLC layer to perform bearer mapping, and the adaptation layer can also be located in PC5 to perform bearer mapping on the side link. The adaptation layer between the relay UE and the gNB can distinguish the bearer (Signaling Radio Bearer (SRB), Data Radio Bearer (DRB)) of a specific remote UE. In one Uu DRB, different remote UEs and different bearers of remote UEs can be indicated by additional information included in the adaptation layer header. Unlike L3 relay, gNB knows each remote UE, so before the relay UE starts forwarding normal data traffic, it first establishes an end-to-end connection between the remote UE and gNB. After the RRC connection is established through the SL relay, the remote UE can then forward the data traffic according to the established bearer and the forwarding/router information carried by the adaptation layer.

In NR, in order to enhance the multimedia telephony (Multimedia Telephony, MMTEL) IP Multimedia Subsystem (IP Multimedia Subsystem, IMS) voice and video, a radio access network (Radio Access Network, RAN) assisted codec adaptation is introduced. RAN-assisted codec adaptation provides a method for gNB to send a codec adaptation indication using the recommended bit rate to assist UE in selecting or adapting the codec rate for MMTEL voice or MMTEL video . RAN-assisted codec adaptation mechanism supports uplink/downlink bit rate increase and decrease. For bearers associated with configurations with a Maximum Bit Rate (MBR) greater than the Guaranteed Bit Rate (GBR), the recommended upstream/downstream bit rates are set in the MBR and GBR settings of the relevant bearer within the boundaries of .

For uplink or downlink bit rate adaptation, the gNB can send the recommended bit rate to the UE to inform the UE of the current recommended transmission bit rate on the local uplink or downlink, and the UE can use it in conjunction with other information to adapt Bit rate, for example, the UE can send a bit rate request to the peer UE through an application layer message, and the peer UE can use it in combination with other information to adapt the codec bit rate. When making a decision, the recommended bit rate is in kbps at the PHY layer.

The recommended bit rate for uplink (Uplink, UL) and downlink (Downlink, DL) is conveyed (conveyed) from gNB to UE as MAC CE. Based on the recommended bit rate from the gNB, the UE can initiate end-to-end bit rate adaptation with the peer (UE or Media Gateway (MGW)). The UE can also send a query message to its local gNB to check whether the gNB can provide the bit rate recommended by the peer. The UE is not expected to exceed the bit rate recommended by the gNB. The query message of the recommended bit rate is passed from UE to gNB as MAC CE.

MAC CE does not support SL relay forwarding. Most MAC CEs are used to manage the link between UE and gNB. However, a few MAC CEs are not used for link management, including (1) bit rate query and recommendation MAC CEs and (2) UL buffer status report (Buffer Status Report, BSR). The current SL relay design does not support MAC CE forwarding, so the far-end UE cannot inform the gNB of its preferred bit rate and what is in the buffer.

A solution needs to be found.

A method may be provided to support a remote UE to transmit a recommended bit rate query to a base station by relaying the UE's processing. In one novel aspect, a new sidelink MAC CE may be introduced to indicate the desired bit rate for a particular sidelink logical channel or a particular Uu/SL radio bearer. In a novel aspect, after receiving the recommended bit rate query MAC CE, the relay UE can send the MAC CE of the remote UE through the Uu interface after adding information related to the identity (ID) of the remote UE. forwarded to the base station. In a novel aspect, when a relay UE receives a recommended bit rate query MAC CE, the MAC CE can be mapped to a specific uplink Logical Channel Priority (LCP) value or a specific uplink logical Channel priority level, used to compare priority with other UL data or UL MAC CE.

A method for a base station to communicate a recommended bit rate to a remote UE may also be provided. In one novel aspect, the recommended bit rate MAC CE of the remote UE may be transmitted from the base station to the relay UE together with the ID of the remote UE. In one novel aspect, after the relay UE receives the recommended bit rate MAC CE, the relay UE may forward the MAC CE to the target remote UE according to the associated remote UE ID. In one novel aspect, the Recommended Bit Rate MAC CE may have a fixed or configured sidelink logical lane priority value, and/or an associated priority value that can be compared with other SL profiles and SL MAC CEs.

A method for wireless communication performed by a relay user equipment, the method comprising: receiving a recommended bit rate query message from a remote user equipment, wherein the message is sent by a control signaling or by the Carried by the control unit of the side-link media access control dedicated to the remote user equipment; when the recommended bit rate query message is carried by the control signaling, it is relayed through the layer 2 side-link forwarding the recommended bit rate query message to a base station; and forwarding the recommended bit rate query message when carried by the sidelink media access control control unit The inquiry message is forwarded to the base station, wherein the control unit of the sidelink media access control has a unique sidelink logical channel identification value, and the sidelink logical channel identification value indicates the recommended Bit rate query message.

A method for wireless communication, performed by a relay user equipment, the method comprising: receiving a recommended bit rate message from a base station, wherein the message is carried by a control signaling or by a remote user The device-specific downlink media access control control unit is carried; when the recommended bit rate information is carried by the control signaling, the recommended bit rate information is relayed through the layer 2 side link forwarding to the remote user equipment; and forwarding the recommended bit rate message to the remote user equipment when the recommended bit rate message is carried by the DL MAC control element or the device, wherein the DL MAC control unit has a DL LCI value indicating the recommended bit rate message.

A relay user equipment for wireless communication, comprising: a receiver for receiving a recommended bit rate query message from a remote user equipment, wherein the message is sent by a sidelink dedicated to the remote user equipment carried by a control unit for media access control, wherein the receiver receives a recommended bit rate message from a base station, wherein the message is provided by a downlink media access control dedicated to the remote user equipment and a relay processing circuit for forwarding the recommended bit rate inquiry message to the base station, wherein the control unit of the sidelink medium access control has a unique sidelink a logical channel identification value, the sidelink logical channel identification value indicating the recommended bit rate query message, wherein the relay processing circuit forwards the recommended bit rate message to the remote user equipment , wherein the DL MAC control element has a DL LCI value, and the DBL ID value indicates the recommended bit rate information.

Reference will now be made in detail to some embodiments of the invention, examples of which are illustrated in the accompanying drawings.

FIG. 1 can illustrate a wireless mobile communication system 100 supporting uplink and downlink MAC CE forwarding via SL relay in accordance with the novel aspects. The 5G NR mobile communication network 100 can include a 5GC 101, a next generation base station gNB 102 and A plurality of user equipments UE103, UE104 and UE105. For UEs within coverage, the base station can schedule data services through the Uu link. For UEs out of coverage, the relay UE can schedule data services through PC5 (or side link). In Figure 1, UE 103 is an RRC-connected UE, which can be used as a mobile device relay to use PC5 (or SL) to relay data services to/from the remote UE of the terminal for coverage extension. The remote UE 104 may not be within network coverage. The relay UE 103 can help relay all data services of the remote UE 104 . The remote UE 105 can connect to the network through the Uu link, but the link quality may be poor. The relay UE 103 may specify to relay part or all of the data services of the remote UE 105 . Relay UE 103 can be used to relay communication between UE 104/105 and the network, thereby allowing the network to effectively extend its coverage to remote UEs.

To support sidelink relaying, there are two UE-to-network relaying architectures, namely layer 2 relaying (L2 relaying) and layer 3 relaying (L3 relaying). However, MAC CE does not support SL relay forwarding. Although most MAC CEs are used to manage the link between UE and gNB, a few MAC CEs are not used for link management, including (1) bit rate query and recommendation MAC CE and (2) UL BSR. For example, the recommended bit rate for uplink and downlink can be delivered as MAC CE from gNB to UE, and the recommended bit rate query message can be delivered as MAC CE from UE to gNB. However, the current SL relay design does not support MAC CE forwarding.

According to a novel aspect, a method can be proposed to allow uplink and downlink MAC CE forwarding through sidelink relay. As shown in Fig. 1, in the uplink, the recommended bit rate query message can be sent from the remote UE and forwarded to the gNB via the new UL MAC CE via the relay UE (step 121). After adding information related to the remote UE ID, the relay UE may forward the new UL MAC CE of the remote UE to the gNB (step 122 ). Similarly, in the downlink, the recommended bit rate DL MAC CE for the remote UE can be transmitted from the gNB to the relay UE together with the ID of the remote UE (step 131), and then can be forwarded by the relay UE to the remote UE. terminal UE (step 132).

FIG. 2 is a simplified block diagram 200 of wireless devices 201 and 211 in accordance with novel aspects. For wireless device 201 , such as a relay UE, antennas 207 and 208 may transmit and receive radio signals. The radio frequency (Radio Frequency, RF) transceiver module 206 can be coupled with the antenna, receives the RF signal from the antenna, converts it into a baseband signal and sends it to the processor 203 . The RF transceiver 206 can also convert the baseband signal received from the processor into an RF signal and send it to the antennas 207 and 208 . The processor 203 processes the received baseband signal and invokes various functional modules and circuits to execute the features in the wireless device 201 . The storage medium 202 may store program instructions and data 210 to control the operation of the device 201 .

Similarly, for wireless device 211 (eg, a remote UE), antennas 217 and 218 can transmit and receive RF signals. The RF transceiver module 216 can be coupled with the antenna, receives the RF signal from the antenna, converts it into a baseband signal and sends it to the processor 213 . The RF transceiver 216 can also convert the baseband signal received from the processor, convert it into an RF signal, and send it to the antennas 217 and 218 . The processor 213 processes the received baseband signal and invokes various functional modules and circuits to execute the features in the wireless device 211 . The storage medium 212 may store program instructions and data 220 to control the operation of the device 211 .

The wireless devices 201 and 211 may also include several functional modules and circuits, which may be implemented and configured to perform embodiments of the present invention. In the example of FIG. 2, the wireless device 201 may be a relay UE and may include a protocol stack 222, a resource management circuit 205 for allocating and scheduling sidelink resources, and a connection processing circuit for establishing and managing connections 204. A relay processing controller 209 for relaying all or part of control signaling and/or data traffic of the remote UE, and a control and configuration circuit 221 for providing control and configuration information. The wireless device 211 may be a remote UE and includes a protocol stack 232 , a relay discovery circuit 214 for discovering relay UEs, a connection processing circuit 219 for establishing and managing connections, and a configuration and control circuit 231 . Different functional modules and circuits can be implemented and configured by software, firmware, hardware and any combination thereof. The above-mentioned functional modules and circuits, when executed by the processors 203 and 213 (for example, by executing the program codes 210 and 220 ), allow the relay UE 201 and the remote UE 211 to perform embodiments of the present invention accordingly.

In case of L2-based SL relay, relaying can be performed above the RLC sublayer via the relay UE for control plane CP and user plane UP between the remote UE and the network. Uu SDAP/PDCP and RRC can be terminated between the remote UE and gNB, while RLC, MAC and PHY can be terminated between each link (i.e. the link between the remote UE and the UE to the network relay UE and the UE to The link between the network relay UE and the gNB) is terminated. Uu supports the adaptation layer on the RLC layer to perform bearer mapping, and the adaptation layer can also be located in PC5 to perform bearer mapping on the side link. The adaptation layer between the relay UE and the gNB is able to distinguish the bearers (SRB, DRB) of a specific remote UE. In one Uu DRB, different remote UEs and different bearers of remote UEs can be indicated by additional information contained in the adaptation layer header. In one example, the remote UE may transmit the recommended bit rate query MAC CE to the base station through the processing of the relay UE. In another example, the remote UE may receive the recommended bit rate MAC CE from the base station through the processing of the relay UE.

FIG. 3 may illustrate an embodiment of forwarding recommended bit rate queries and recommended bit rate messages via RLC SDUs in accordance with novel aspects. In L2 relay, the base station can know every remote UE connected to the base station through the relay UE. Recommended bit rate queries aimed at enhancing MMTEL voice and video QoS can be used for end-to-end applications. Therefore, in order to ensure good end-to-end QoS, it is better for the gNB to have a clear idea of the expected bit rate of each remote UE. To transmit the recommended bit rate query, the remote UE may send the desired bit rate to the base station through the relay UE.

In the embodiment of FIG. 3 , the recommended bit rate inquiry message may be carried by control signaling, for example, carried by an RLC SDU on an uplink dedicated control channel (Uplink Dedicated Control Channel, UL-DCCH). For example, the information of the recommended bit rate query can be included in the existing RRC signaling, for example, included in the sidelink UE information (SidelinkUEInformation) message, or the UE assistance information (UEAssistanceInformation) message or a new RRC message, The above RRC signaling may be included in the RLC SDU, and transmitted from the remote UE 303 (step 311 ) to the base station 301 through forwarding by the relay UE 302 (step 312 ). In this embodiment, the recommended bit rate query message is transmitted through dedicated signaling (ie, the same way that the remote UE sends UL data to the base station through the L2 SL relay).

Similarly, the base station can send the recommended bit rate to the remote UE to suggest a suitable bit rate. In L2 relay, since the gNB knows the existence of each remote UE, the recommended bit rate information from the gNB can be received by the remote UE. In one embodiment, as shown in Figure 3, the recommended bit rate information can be carried by control signaling, for example, it can be carried by RLC SDU on DL-DCCH, and then the relay UE can forward it through the sidelink to the remote UE. For example, the information on the recommended bit rate can be included in the existing RRC signaling, such as included in the RRC reconfiguration (RRCReconfiguration) message, and the above RRC signaling can be included in the RLC SDU and passed from gNB 301 (step 321) The forwarding (step 322 ) of the relay UE 302 is transmitted to the remote UE 303 . In this embodiment, the recommended bit rate is transmitted through dedicated signaling (ie, the same way that the base station sends DL data to the remote UE through the L2 SL relay).

Fig. 4 may illustrate an embodiment of forwarding a recommended bit rate query via a UL MAC CE in accordance with novel aspects. If the desired bit rate is carried by the sidelink MAC CE, there are different ways it can be conveyed from the remote UE 404 to the relay UE 403 (step 411 ). In one embodiment, the sidelink MAC CE for the recommended bit rate query may be multiplexed into the SL MAC PDU according to conventional LCP and multiplexing procedures similar to other sidelink MAC CEs. In one embodiment, the sidelink MAC CE for the recommended bit rate query can be regarded as a typical SL RLC SDU profile. It can also be said that a MAC sub-PDU (subPDU) can be formed by adding an adaptation layer header, optionally adding an SL RLC header, and adding a MAC subheader (subheader), wherein, in the logical channel identification (Logical Channel ID, LCID) The LCID value indicated in the field and/or the eLCID field may inform the receiver that the MAC sub-PDU is used to carry the recommended bit rate query. Then, the MAC sub-PDU containing the recommended bit rate query may be forwarded from the remote UE 404 to the gNB 401 via the relay UE 403 and the relay UE 402 .

After the relaying UE receives the recommended bit rate query, there are several ways to handle the query. In one embodiment, if the recommended bit rate query is carried in a format without an associated RLC header or adaptation layer header SL MAC CE, the relaying UE may treat the SL MAC CE as an RLC SDU. This means that the relay UE can add an adaptation layer header and an RLC header before the SL MAC CE payload to form an RLC PDU, which can then be delivered to the gNB by applying the traditional Uu LCP procedure. When the RLC PDU is multiplexed into the UL MAC PDU, the MAC subheader associated with the RLC PDU of the recommended bit rate query may include the UL LCID corresponding to the "recommended bit rate query MAC CE from the remote UE" value. For a multi-hop scenario, the relay UE 403 can package the SL MAC CE into an SL RLC PDU, and then transmit it to the upstream relay UE by applying the traditional sidelink LCP process 402. Similarly, the MAC subheader of the SL RLC SDU may have a LCID to identify the content of the RLC SDU as a Recommended Bit Rate Query MAC CE. In one example, the added adaptation layer header may include the ID of the remote UE that initiated the query.

In one embodiment, if the recommended bit rate query is carried in the format of the SL MAC CE with associated RLC header or adaptation layer header, the relaying UE may update the RLC header and adaptation layer header and then send the updated The RLC PDU is forwarded to the next hop (i.e. gNB or upstream relay UE). If the relay UE 402 forwards the RLC PDU to the gNB 401 (step 413), the MAC subheader of the RLC PDU may indicate the LCID value corresponding to the recommended bit rate query MAC CE from the far-end UE. Conversely, if the relay UE 403 forwards the RLC PDU to the upstream relay UE 402 (step 412), the SL MAC subheader of the RLC PDU may indicate the LCID value corresponding to the recommended bit rate query SL MAC CE.

Fig. 5 may illustrate an embodiment of forwarding a recommended bit rate via a DL MAC CE in accordance with novel aspects. A new MAC CE type can be defined to carry the recommended bit rate information from gNB to remote UE. The MAC CE type may have its own downlink LCID value, which may be defined by the LCID field or both the LCID field and the e-LCID field in the MAC subheader (step 511 ). In case the MAC subheader indicates the LCID value corresponding to the recommended bit rate MAC CE of the remote UE, the corresponding MAC CE payload may include the information of the remote UE, such as the ID of the remote UE.

In one example, in order to send the recommended bit rate for the remote UE, the gNB can put the information of the target remote UE (such as the ID of the target remote UE) into the adaptation layer header, and the above-mentioned other information can include in the payload of the MAC CE. For example, the gNB can regard the MAC CE payload as an RLC SDU, so it can add an adaptation layer header, an optional RLC header, and a MAC sub-header to it in sequence to form a MAC sub-PDU. After the relay UE receives a DL MAC PDU containing a MAC sub-PDU, the relay UE can know that the MAC sub-PDU carries a MAC sub-PDU for the remote end by checking the LCID value indicated in the LCID and/or eLCID fields in the MAC sub-header. UE's Recommended Bit Rate MAC CE. The relay UE can then update the RLC header (if present and required) and the adaptation layer header (if required) and forward the SL RLC SDU to the remote UE (step 513) or to the downstream relay UE (step 512) . When multiplexing an SL RLC SDU to an SL MAC PDU, the SL MAC subheader associated with the SL RLC SDU may include the LCID value corresponding to the recommended bit rate MAC CE on the sidelink. Note that, similar to the Recommended Bit Rate Query MAC CE on the Sidelink, the Recommended Bit Rate MAC CE on the Sidelink may have a unique LCID value.

There are two ways for the relay UE to forward the recommended bit rate MAC CE to the remote UE. In one embodiment, the MAC CE payload can form an SL MAC sub-PDU together with the adaptation layer header, optional RLC header and MAC sub-header, and is sent by the relay UE to the remote UE. The remote UE can learn from the LCID of the MAC sub-header of the MAC sub-PDU that the MAC sub-PDU is a recommended bit rate MAC CE, and remove the RLC header and the adaptation layer header to read the MAC CE payload. In one embodiment, only the MAC CE payload and the MAC sub-header may form a MAC sub-PDU. When receiving the MAC sub-PDU, the remote UE can learn from the LCID of the MAC sub-header of the MAC sub-PDU that the MAC sub-PDU is a recommended bit rate MAC CE.

Fig. 6 may illustrate an embodiment of SL MAC CE forwarding in UE-to-UE relay according to novel aspects. The framework of exchanging UL MAC CE or DL MAC CE between the network and the remote UE through the relay UE can also be applied to the scenario of UE-to-UE relay. For UE-to-UE relay, the SL MAC CE can be forwarded by the relay UE instead of the UL or DL MAC CE. The forwarding mode of SL MAC CE is similar to that of UL and DL MAC CE in UE-to-Network relay. An adaptation layer header (eg, for routing purposes) may be added to the SL MAC CE to form an SL MAC sub-PDU. Furthermore, an indicator may be used to indicate that the SL MAC sub-PDU includes (a certain type of) SL MAC CE, eg a specific sidelink LCID value may be applied in the MAC sub-header of the SL MAC sub-PDU.

For SL MAC CE forwarding, since the source and target of SL MAC CE are both UEs, the adaptation layer header can contain both the source UE ID and the target UE ID, so that the target UE can know which UE initiates the SL MAC through the source UE ID CE. In the example in Figure 6, the SL MAC CE can be encapsulated into an SL MAC sub-PDU, which can be sent from the source UE 601 (step 611), and based on the routing information in the adaptation layer header (including source ID and Target ID) is forwarded from the source UE to the target UE 604 via the relay UE 602 (step 612) and the relay UE 603 (step 613).

Fig. 7 may illustrate an exemplary SL MAC PDU format with SL-SCH MAC subheader for MAC CE forwarding in accordance with the novel aspects. An SL MAC PDU may include an SL-SCH MAC sub-header, several MAC sub-PDUs, and padding. Each MAC sub-PDU can carry data or MAC CE. A MAC sub-PDU for data may include a MAC sub-header and a MAC SDU. The MAC subheader format for data may have a field "L" to indicate the size (number of bytes) of the MAC SDU. A MAC sub-PDU for a MAC CE may include a MAC sub-header and a MAC CE. Since all currently supported SL MAC CEs have a fixed size, the MAC subheader format for the MAC CE may not have the field "L".

The SL-SCH MAC subheader may include a SRC field and a DST field to indicate who sent the SL MAC PDU (SRC) and who should receive the SL MAC PDU (DST). For example, if the remote UE sends SL MAC PDU to relay UE2, relay UE1, and then to gNB, when the remote UE sends SL MAC PDU through SL, the DST field is relay UE2, when relay UE2 forwards SL In MAC PDU, the SRC field is the relay UE2, and the DST field is the relay UE1.

The LCID for SL-LCH can be used to indicate the content of the payload in the SL MAC sub-PDU. For example, if the value of LCID is less than 20, the payload may be MAC SDU, and if the value of LCID is equal to 62, the payload may be MAC CE for SL channel state information (Channel State Information, CSI) report. In the current MAC specification, there are two tables that can define the LCID values of DL-LCH and UL-SCH. For example, the LCID of the recommended bit rate DL message may be 47, and the LCID of the recommended bit query UL message may be 53. According to a novel aspect, two SL LCID values may be added to the LCID table for SL-SCH. First, the "SL Recommended Bit Rate Query MAC CE" with LCID 61 for UE to gNB (uplink direction) can be added as the counterpart of the "UL Recommended Bit Rate Query MAC CE". Secondly, "SL recommended bit rate" with LCID of 60 for gNB to UE (downlink direction) can be added as a corresponding item of "DL recommended bit rate MAC CE".

Figure 8 may illustrate an embodiment of UL MAC CE forwarding through UE to network SL relay in accordance with novel aspects. In step 811 , the remote UE 804 may send the UL MAC CE to the relay UE 803 . In step 812 , the relay UE 803 may forward the UL MAC CE to the relay UE 802 . In step 813 , the relaying UE 802 may forward the UL MAC CE to the gNB 801 . In this example, when the relay UE forwards the far-end UE's recommended bit-rate query to the base station, the UL LCID contained in the MAC subheader of the recommended bit-rate query MAC CE from the far-end UE can be compared with the traditional recommended bit rate The UL LCID of the bit rate inquiry MAC CE is different. Otherwise, the gNB may think that the recommended bit rate query is from the relaying UE itself, and will not be able to decode the content of the MAC CE payload.

In order to distinguish the recommended bit rate query MAC CE of the relay UE and the remote UE, the recommended bit rate query MAC CE of the remote UE may have different SL LCIDs, for example, the SL LCID may be set to 61. In the present invention, since the UL MAC CE can only be used in the SL relay scenario, it can be called "relay-specific recommended bit rate query". When the relay UE 802 checks the SL MAC subheader and finds that the SL LCID value is 61, the relay UE 802 can know that this MAC payload contains the MAC CE for the "recommended bit rate query", so in the UL transmission (from the relay 802 to gNB 801), the relay UE 802 may select the UL LCID value for the "recommended bit rate query", ie 53 as defined in the UL LCID table.

In the present invention, a method on how to transmit the UL MAC CE (Recommended Bit Rate Query MAC CE) from the remote UE to the base station is proposed. One of the main ideas is that when forwarding a MAC CE, the MAC CE can add an adaptation layer header for routing. With the addition of the Adaptation Layer header, an additional LCID is required. For example, in order to forward the UL MAC CE, a new relay-specific UL LCID is needed, so that when the base station receives the UL MAC CE, the base station can know that the UL MAC CE comes from the remote UE, and can know that the Adaptation layer header included in the MAC SDU.

In an embodiment, the relay UE may forward the SL MAC sub-PDU to the base station as a UL MAC sub-PDU by converting the SL LCID to the corresponding UL LCID for the recommended bit rate inquiry message.

Fig. 9 may illustrate an embodiment of DL MAC CE forwarding through UE to network SL relay in accordance with novel aspects. In step 911 , gNB 901 may send DL MAC CE to relay UE 902 . In step 912 , the relay UE 902 may forward the DL MAC CE to the relay UE 903 . In step 913 , the relay UE 903 may forward the DL MAC CE to the remote UE 904 . In this example, when the base station sends the recommended bit rate MAC CE to the remote UE, the base station may not apply the existing LCID to the recommended bit rate MAC CE in the MAC subheader. Otherwise, the relay UE will consider that the recommended bit rate MAC CE is for the relay UE itself, not for the remote UE.

To avoid ambiguity, the recommended bit rate MAC CE for the remote UE may be assigned a different SL LCID, for example, the SL LCID may be set to 60. In the present invention, since the DL MAC CE can only be used in the SL relay scenario, it can be called "relay-specific recommended bit rate". When the relay UE 902 checks the DL MAC subheader and finds that the DL LCID value is 47, the relay UE 902 can know that this MAC payload contains the MAC CE for the "recommended bit rate", so in the SL transmission (from the relay UE 902 to relay UE 903), the relay UE 902 may select the SL LCID value for the "recommended bit rate", ie 60 as defined in the SL LCID table.

In the present invention, a method on how to transmit DL MAC CE (Recommended Bit Rate MAC CE) from base station to remote UE is proposed. One of the main ideas is that when forwarding a MAC CE, the MAC CE can add an adaptation layer header for routing. With the addition of the Adaptation Layer header, an additional LCID is required. For example, in order to forward the DL MAC CE, a new relay-specific DL LCID is required, so that when the relay UE receives the DL MAC sub-PDU, the relay UE can know the existence of the adaptation layer header, so that it can perform routing correctly.

In one embodiment, the relay UE may forward the DL MAC sub-PDU to the remote UE as an SL MAC sub-PDU by converting the DL LCID to the corresponding SL LCID for the recommended bit rate message.

The above frame can also be used to carry other UL MAC CEs or DL MAC CEs. For example, it would be useful if the remote UE could send a UL BSR by relaying the UE's forwarding to inform the gNB of the amount of uplink data it has available in the uplink buffer. Based on the feedback from the remote UE, if the remote UE has a large amount of data to transmit, the base station can provide sufficient resources or a higher priority along the path to forward the traffic of the remote UE.

10 is a flowchart of a method of MAC CE relaying a recommended bit rate inquiry message through a sidelink in accordance with novel aspects. In step 1001, the relay UE may receive a recommended bit rate query message from a remote UE. The information can be carried by control signaling or carried by the SL MAC CE dedicated to the remote UE. In step 1002, when the recommended bit rate query message is carried in the control signaling, the relay UE may relay the message to the base station through layer 2 sidelink relay. In step 1003, when the recommended bit rate query message is carried by the SL MAC CE, the relay UE may forward the message to the base station. The SL MAC CE may have a unique SL LCID value which may indicate the recommended bit rate query message.

11 is a flowchart of a method of MAC CE relaying a recommended bit rate message through a sidelink in accordance with the novel aspects. In step 1101, the relay UE may receive a recommended bit rate message from a base station. The information can be carried by control signaling or by a DL MAC CE dedicated to the remote UE. In step 1102, when the recommended bit rate information is carried in the control signaling, the relay UE may forward the information to the remote UE through Layer 2 sidelink relay. In step 1103, when the recommended bit rate message is carried by the DL MAC CE, the relay UE may forward the message to the remote UE. The DL MAC CE may have a DL LCID value which may indicate the recommended bit rate information.

Although the present invention is disclosed above in conjunction with specific embodiments for the purpose of instruction, the present invention is not limited thereto. Accordingly, various modifications, adjustments and combinations can be made to the various features of the above-mentioned embodiments without departing from the scope set forth in the claims of the present invention.

100:Mobile communication system 101:5GC 102, 301, 401, 501, 801, 901: gNB 103, 104, 105, 302, 303, 402~404, 502~504, 601~604, 802~804, 902~904:UE 121, 122, 131, 132, 311, 312, 321, 322, 411~413, 511~513, 611~613, 811~813, 911~913, 1001~1003, 1101~1103: steps 200: block diagram 201, 211: Wireless devices 202, 212: storage medium 203, 213: Processor 207, 208, 217, 218: Antennas 204, 219: connection processing circuit 205: resource management circuit 206, 216: Transceiver 209: relay processing controller 210, 220: Program instructions 214: Relay discovery circuit 221, 231: Control and configuration circuits 222, 232: protocol stacking

FIG. 1 may illustrate a wireless mobile communication system supporting uplink and downlink MAC CE forwarding through SL relay in accordance with novel aspects. Figure 2 is a simplified block diagram of a wireless transmitting device and receiving device in accordance with an embodiment of the present invention. FIG. 3 may illustrate an embodiment of forwarding a recommended bit rate query and a recommended bit rate message via an RLC Service Data Unit (SDU) in accordance with the novel aspects. FIG. 4 may illustrate an embodiment of forwarding a recommended bit rate query message via a UL MAC CE in accordance with the novel aspects. FIG. 5 may illustrate an embodiment of forwarding a recommended bit rate message via a DL MAC CE in accordance with the novel aspects. Fig. 6 may illustrate an embodiment of SL MAC CE forwarding in UE-to-UE relay according to novel aspects. Figure 7 may illustrate an exemplary SL MAC Protocol Data Unit (PDU) format with a Sidelink Shared Channel (SL-SCH) MAC subheader for MAC CE forwarding in accordance with the novel aspects . Figure 8 may illustrate an embodiment of UL MAC CE forwarding through UE to network SL relay in accordance with novel aspects. Figure 9 may illustrate an embodiment of DL MAC CE forwarding through UE to network SL relay in accordance with novel aspects. 10 is a flowchart of a method of MAC CE relaying a recommended bit rate inquiry message through a sidelink in accordance with novel aspects. 11 is a flowchart of a method of MAC CE relaying a recommended bit rate message through a sidelink in accordance with the novel aspects.

1001~1003: Steps

Claims (18)

A method for wireless communication, performed by a relay user equipment, the method comprising: receiving a recommended bit rate inquiry message from a remote user equipment, wherein the message is carried by a control signaling or by a control element of a side link media access control dedicated to the remote user equipment; forwarding the recommended bit rate query message to a base station via layer 2 sidelink relay when the recommended bit rate query message is carried by the control signaling; and When the recommended bit rate query message is carried by the sidelink media access control control unit, forward the recommended bit rate query message to the base station, wherein the sidelink The MAC control unit has a unique SLLCID value indicating the RBR query message. The method for wireless communication as claimed in claim 1, wherein the control signaling is a radio resource control signaling, and the recommended bit rate query message is included in a radio link control service data unit The radio resource control signaling is carried. The method for wireless communication as recited in claim 1, wherein the control unit of the side link media access control forms a side link media access control subheader with a side link media access control Fetch control sub-protocol data unit, wherein the side-link MAC sub-header includes the unique side-link logical channel identification value which is different from the existing logical channel identification value. The method for wireless communication as recited in claim 3, wherein said sidelink MAC control element does not have an associated RLC header or an associated ALA header. The method for wireless communication as recited in claim 4, wherein said relay user equipment adds an adaptation layer header and a radio link control before said control element of sidelink media access control layer header to form a RLC SDU for forwarding to the base station. The method for wireless communication as recited in claim 3, wherein said sidelink MAC control element has an associated adaptation layer header. The method for wireless communication as recited in claim 6, wherein said sidelink MAC control element further has an associated RLC header. The method for wireless communication as claimed in claim 6 or 7, wherein the relay user equipment updates the associated adaptation layer header or updates the associated adaptation layer header and the radio Both the link control header and the sidelink MAC control element are forwarded as a RLC protocol data unit. The method for wireless communication as recited in claim 3, wherein the relay UE converts the sidelink logical channel identifier into a corresponding uplink for the recommended bit rate query message A logical channel identifier is used to forward the sidelink MAC sub-protocol data unit to the base station as an uplink media access control sub-protocol data unit. A method for wireless communication, performed by a relay user equipment, the method comprising: receiving a recommended bit rate message from a base station, wherein the message is carried by a control signaling or by a DL MAC control element dedicated to a remote user equipment; forwarding the recommended bit rate message to the remote user equipment via layer 2 sidelink relay when the recommended bit rate message is carried by the control signaling; and forwarding the recommended bit rate message to the remote UE when the recommended bit rate message is carried by the DL MAC control element, wherein the DL MAC is stored The control unit that takes control has a downlink logical channel identification value indicating the recommended bit rate information. The method for wireless communication as claimed in claim 10, wherein said control signaling is a radio resource control signaling, wherein said recommended bit rate information is included in a radio link control service data unit carried by the radio resource control signaling. The method for wireless communication as recited in claim 10, wherein said recommended bit rate information is included in a payload of said downlink MAC control element, wherein said downlink The MAC control element has a new MAC control element type and a downlink logical channel identifier in the downlink MAC subheader. The method for wireless communication as recited in claim 10, wherein the recommended bit rate information is included in the payload of the control element of the downlink media access control, wherein an adaptation layer header is added and a MAC sub-header to form a downlink MAC sub-protocol data unit. The method for wireless communication as recited in claim 13, wherein the control element payload of the downlink media access control, the adaptation layer header and the media access control subheader form a side row A link MAC sub-protocol data unit is forwarded by the relay UE to the remote UE. The method for wireless communication as recited in claim 13, wherein a downlink media access control is formed by the control element payload of the downlink media access control and the media access control subheader sub-protocol data unit, and forwarded by the relay user equipment to the remote user equipment. The method for wireless communication as recited in claim 13, wherein said relay UE converts said downlink logical channel identification into a corresponding sidelink for said recommended bit rate message A logical channel identifier, forwarding the DL MAC sub-protocol data unit as a downlink MAC sub-protocol data unit to the remote UE. The method for wireless communication as recited in claim 16, wherein the sidelink logical channel indicated in a media access control subheader of the sidelink media access control sub-protocol data unit The identification value is specific to the recommended bit rate of the remote user equipment and is different from the existing sidelink logical channel identification value. A relay user equipment for wireless communication, comprising: a receiver receiving a recommended bit rate query message from a remote user equipment carried by a sidelink media access control control element dedicated to said remote user equipment, wherein the receiver receives a recommended bit rate message from a base station, wherein the message is carried by a DL MAC control element dedicated to the remote user equipment; and A relay processing circuit, forwarding the recommended bit rate query message to the base station, wherein the control unit of the sidelink media access control has a unique sidelink logical channel identification value, so the sidelink logical channel identifier value indicates the recommended bit rate query message, Wherein, the relay processing circuit forwards the recommended bit rate message to the remote UE, wherein the control unit of the downlink MAC has a downlink logical channel identification value, so The DLLCID value indicates the recommended bit rate information.

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