Subchannel selection and channel state information (csi) indication via buffer status report (bsr) for sidelink

Abstract

Wireless communications systems and methods related to providing subchannel selection or recommendation and/or channel state information (CSI) for sidelink communications (e.g., operating in mode-1 radio resource allocation (RRA) via a buffer status report (BSR) are provided. A first user equipment (UE) transmits, to a base station (BS), a BSR indicating subchannel information associated with one or more UEs. The UE receives, from the BS in response to the BSR report, a grant for transmitting a first sidelink transmission to a second UE of the one or more UEs. The UE transmits, to the second UE based on the grant, the first sidelink transmission.

What is claimed is: 
     
         1 . A method of wireless communication performed by a first user equipment (UE), the method comprising:
 transmitting, to a base station (BS), a buffer status report (BSR) indicating subchannel information associated with one or more UEs;   receiving, from the BS in response to the BSR report, a grant for transmitting a first sidelink transmission to a second UE of the one or more UEs; and   transmitting, to the second UE based on the grant, the first sidelink transmission.   
     
     
         2 . The method of  claim 1 , wherein:
 the transmitting the BSR comprises:
 transmitting, to the BS, the BSR further indicating at least one of a destination index, a logical channel group (LCG) identifier (ID), or a buffer size associated with the second UE, and 
   the subchannel information indicates at least one of one or more subchannels or a number of subchannels associated with the second UE.   
     
     
         3 . The method of  claim 2 , wherein the subchannel information indicates the one or more subchannels in an order of preference. 
     
     
         4 . The method of  claim 2 , wherein the subchannel information comprises a codeword indicating a starting subchannel of the one or more subchannels and the number of subchannels. 
     
     
         5 . The method of  claim 2 , wherein the subchannel information indicates the number of subchannels by indicating a common number of subchannels in the one or more subchannels. 
     
     
         6 . The method of  claim 5 , wherein the transmitting the BSR further comprises:
 transmitting, to the BS, the BSR comprising:
 a first block indicating a first LCG ID associated with the second UE, the common number of subchannels, and a first subchannel of the one or more subchannels; and 
 a second block indicating a second LCG ID associated with the second UE and a second subchannel of the one or more subchannels, the second subchannel being different from the first subchannel. 
   
     
     
         7 . The method of  claim 1 , wherein:
 the transmitting the BSR comprises:
 transmitting, to the BS, the BSR further indicating at least one of a destination index, a logical channel group (LCG) identifier (ID), or a buffer size associated with the second UE, and 
   the subchannel information indicates at least one of a rank indicator (RI), a channel quality indicator (CQI), or a subchannel associated with the second UE.   
     
     
         8 . The method of  claim 1 , wherein the transmitting the BSR comprises:
 transmitting, to the BS, the BSR comprising:
 a first block comprising a destination index, a logical channel group identifier (LCG ID), a buffer size, and first subchannel information associated with the second UE; and 
 a second block comprising the destination index, the LCG ID, the buffer size, and second subchannel information associated with the second UE, the second subchannel information being different from the first subchannel information. 
   
     
     
         9 . The method of  claim 1 , wherein the transmitting the BSR including the subchannel information further comprises:
 transmitting, to the BS, the BSR comprising:
 a first block comprising a destination index, a first logical channel group identifier (LCG ID), a first buffer size, and first subchannel information associated with the second UE; and 
 a second block comprising the destination index, a second LCG ID different from the first LCG ID, a second buffer size, and second subchannel information associated with the second UE. 
   
     
     
         10 . The method of  claim 1 , wherein the transmitting the BSR comprises:
 transmitting, to the BS, a medium access control-control element (MAC-CE) comprising:
 a first block comprising a first destination index, a first logical channel group identifier (LCG ID), a first buffer size, and first subchannel information associated with the second UE; and 
 a second block comprising a second destination index, a second LCG ID, a second buffer size, and second subchannel information associated with a third UE of the one or more UEs. 
   
     
     
         11 . The method of  claim 1 , wherein the transmitting the BSR comprises:
 transmitting, to the BS, a medium access control-control element (MAC-CE) comprising:
 a first block comprising a destination index, a logical channel group identifier (LCG ID), and a buffer size associated with the second UE; and 
 a second block comprising first subchannel information associated with the second UE and at least one of the destination index or the LCG ID. 
   
     
     
         12 . The method of  claim 1 , wherein the transmitting the BSR comprises:
 transmitting, to the BS, a bundled medium access control-control element (MAC-CE) comprising:
 a first MAC-CE comprising a destination index, a logical channel group identifier (LCG ID), and a buffer size associated with the second UE; and 
 a second MAC-CE comprising first subchannel information associated with the second UE and at least one of the destination index or the LCG ID. 
   
     
     
         13 . A method of wireless communication performed by a base station (BS), the method comprising:
 receiving, from a first user equipment (UE), a buffer status report (BSR) indicating subchannel information associated with one or more UEs; and   transmitting, to the first UE in response to the BSR report, a grant for transmitting a first sidelink transmission to a second UE of the one or more UEs.   
     
     
         14 . The method of  claim 13 , wherein:
 the receiving the BSR comprises:
 receiving, from the first UE, the BSR further indicating at least one of a destination index, a logical channel group (LCG) identifier (ID), or a buffer size associated with the second UE, and 
   the subchannel information indicates at least one of one or more subchannels or a number of subchannels associated with the second UE.   
     
     
         15 . The method of  claim 14 , wherein the subchannel information indicates the one or more subchannels in an order of preference. 
     
     
         16 . The method of  claim 14 , wherein the subchannel information comprises a codeword indicating a starting subchannel of the one or more subchannels and the number of subchannels. 
     
     
         17 . The method of  claim 14 , wherein the subchannel information indicates the number of subchannels by indicating a common number of subchannels in the one or more subchannels. 
     
     
         18 . The method of  claim 17 , wherein the receiving the BSR further comprises:
 receiving, from the first UE, the BSR comprising:
 a first block indicating a first LCG ID associated with the second UE, the common number of subchannels, and a first subchannel of the one or more subchannels; and 
 a second block indicating a second LCG ID associated with the second UE and a second subchannel of the one or more subchannels, the second subchannel being different from the first subchannel. 
   
     
     
         19 . The method of  claim 13 , wherein:
 the receiving the BSR comprises:
 receiving, from the first UE, the BSR further indicating at least one of a destination index, a logical channel group (LCG) identifier (ID), or a buffer size associated with the second UE, and 
   the subchannel information indicates at least one of a rank indicator (RI), a channel quality indicator (CQI), or a subchannel associated with the second UE.   
     
     
         20 . The method of  claim 13 , wherein the receiving the BSR comprises:
 receiving, from the first UE, the BSR comprising:
 a first block comprising a destination index, a logical channel group identifier (LCG ID), a buffer size, and first subchannel information associated with the second UE; and 
 a second block comprising the destination index, the LCG ID, the buffer size, and second subchannel information associated with the second UE, the second subchannel information being different from the first subchannel information. 
   
     
     
         21 . The method of  claim 13 , wherein the receiving the BSR including the subchannel information further comprises:
 receiving, from the first UE, the BSR comprising:
 a first block comprising a destination index, a first logical channel group identifier (LCG ID), a first buffer size, and first subchannel information associated with the second UE; and 
 a second block comprising the destination index, a second LCG ID different from the first LCG ID, a second buffer size, and second subchannel information associated with the second UE. 
   
     
     
         22 . The method of  claim 13 , wherein the receiving the BSR comprises:
 receiving, from the first UE, a medium access control-control element (MAC-CE) comprising:
 a first block comprising a first destination index, a first logical channel group identifier (LCG ID), a first buffer size, and first subchannel information associated with the second UE; and 
 a second block comprising a second destination index, a second LCG ID, a second buffer size, and second subchannel information associated with a third UE of the one or more UEs. 
   
     
     
         23 . The method of  claim 13 , wherein the receiving the BSR comprises:
 receiving, from the first UE, a medium access control-control element (MAC-CE) comprising:
 a first block comprising a destination index, a logical channel group identifier (LCG ID), and a buffer size associated with the second UE; and 
 a second block comprising first subchannel information associated with the second UE and at least one of the destination index or the LCG ID. 
   
     
     
         24 . The method of  claim 13 , wherein the receiving the BSR comprises:
 receiving, to the BS, a bundled medium access control-control element (MAC-CE) comprising:
 a first MAC-CE comprising a destination index, a logical channel group identifier (LCG ID), and a buffer size associated with the second UE; and 
 a second MAC-CE comprising first subchannel information associated with the second UE and at least one of the destination index or the LCG ID. 
   
     
     
         25 . A first user equipment (UE) comprising:
 a processor; and   a transceiver coupled to the processor, wherein the transceiver is configured to:
 transmit, to a base station (BS), a buffer status report (BSR) indicating subchannel information associated with one or more UEs; 
 receive, from the BS in response to the BSR report, a grant for transmitting a first sidelink transmission to a second UE of the one or more UEs; and 
 transmit, to the second UE based on the grant, the first sidelink transmission. 
   
     
     
         26 . The first UE of  claim 25 , wherein:
 the transceiver configured to transmit the BSR is configured to:
 transmit, to the BS, the BSR further indicating at least one of a destination index, a logical channel group (LCG) identifier (ID), or a buffer size associated with the second UE, and 
   the subchannel information indicates at least one of one or more subchannels or a number of subchannels associated with the second UE.   
     
     
         27 . The first UE of  claim 25 , wherein:
 the transceiver configured to transmit the BSR is configured to:
 transmit, to the BS, the BSR further indicating at least one of a destination index, a logical channel group (LCG) identifier (ID), or a buffer size associated with the second UE, and 
   the subchannel information indicates at least one of a rank indicator (RI), a channel quality indicator (CQI), or a subchannel associated with the second UE.   
     
     
         28 . A base station (BS) comprising:
 a processor; and   a transceiver coupled to the processor, wherein the transceiver is configured to:
 receive, from a first user equipment (UE), a buffer status report (BSR) indicating subchannel information associated with one or more UEs; and 
 transmit, to the first UE in response to the BSR report, a grant for transmitting a first sidelink transmission to a second UE of the one or more UEs. 
   
     
     
         29 . The BS of  claim 28 , wherein:
 the transceiver configured to receive the BSR is configured to:
 receive, from the first UE, the BSR further indicating at least one of a destination index, a logical channel group (LCG) identifier (ID), or a buffer size associated with the second UE, and 
   the subchannel information indicates at least one of one or more subchannels or a number of subchannels associated with the second UE.   
     
     
         30 . The BS of  claim 28 , wherein:
 the transceiver configured to receive the BSR is configured to:
 receive, from the first UE, the BSR further indicating at least one of a destination index, a logical channel group (LCG) identifier (ID), or a buffer size associated with the second UE, and 
   the subchannel information indicates at least one of a rank indicator (RI), a channel quality indicator (CQI), or a subchannel associated with the second UE.