Signaling overhead reduction in noma

Abstract

The present disclosure relates to methods and devices for communicating based on improved signaling. A base station can transmit an indication of resources in time and frequency to a UE allocated for NOMA communication with the UE. The indication of resources can comprise a set of NA-RUs. The UE can then transmit uplink NOMA communication to the base station based on the indication of resources received from the base station. Also, the base station can transmit a compact UL resource grant via DCI, or signal the semi-static transport format configuration via RRC, to the UEs allocated for NOMA communication. The DCI or the payload of RRC signaling can be scrambled with a NOMA group RNTI, as well as comprise NOMA transmission parameters indicated by a MCS table. The UE can then transmit uplink NOMA communication to the base station based on the DCI or the RRC signaling.

What is claimed is: 
     
         1 . A method of wireless communication at a user equipment (UE), comprising:
 receiving, from a base station, an indication of resources in time and frequency allocated for random access channel (RACH) communication with the base station, wherein the indication of resources comprises a set of RACH resources, wherein the set of RACH resources is mapped to a time frequency resource grid with respect to a synchronization signal block (SSB) based on at least one of a center frequency of a RACH resource or a number of physical resource blocks (PRBs) within each RACH resource in the set of RACH resources, wherein the indication of resources is based on a mapping index for the set of RACH resources mapped to the time frequency resource grid and indexed in a sequential order, wherein the mapping index maps at least one of the set of RACH resources to the time frequency resource grid; and   transmitting, to the base station, a message A (msgA) of a two-step RACH procedure based on the indication of resources received from the base station.   
     
     
         2 . The method of  claim 1 , wherein the indication of resources is based on a raster of candidate locations for the set of RACH resources. 
     
     
         3 . The method of  claim 1 , wherein the indication comprises a starting location of the set of RACH resources and a number of the RACH resources comprised in the set of RACH resources. 
     
     
         4 . The method of  claim 1 , wherein the indication comprises a starting location of the set of RACH resources and an ending location of the set of RACH resources. 
     
     
         5 . The method of  claim 1 , wherein the set of RACH resources comprises a number of the RACH resources that are contiguous in time or frequency. 
     
     
         6 . The method of  claim 1 , wherein the set of RACH resources is interlaced in time or frequency within a resource grid spanning a system bandwidth in frequency and at least one slot in time. 
     
     
         7 . The method of  claim 1 , wherein the msgA of the two-step RACH procedure is transmitted to the base station, and multiple UEs share the set of RACH resources in a time and frequency domain. 
     
     
         8 . A method of wireless communication at a base station, comprising:
 transmitting, to a user equipment (UE), an indication of resources in time and frequency allocated for random access channel (RACH) communication with the UE, wherein the indication of resources comprises a set of RACH resources, wherein the set of RACH resources is mapped to a time frequency resource grid with respect to a synchronization signal block (SSB) based on at least one of a center frequency of a RACH resource or a number of physical resource blocks (PRBs) within each RACH resource in the set of RACH resources, wherein the indication of resources is based on a mapping index for the set of RACH resources mapped to the time frequency resource grid and indexed in a sequential order, wherein the mapping index maps at least one of the set of RACH resources to the time frequency resource grid; and   receiving, from the UE, a message A (msgA) of a two-step RACH procedure based on the indication of resources transmitted to the UE.   
     
     
         9 . The method of  claim 8 , wherein the indication of resources is based on a raster of candidate locations for the set of RACH resources. 
     
     
         10 . The method of  claim 8 , wherein the indication comprises a starting location of the set of RACH resources and a number of the RACH resources comprised in the set of RACH resources. 
     
     
         11 . The method of  claim 8 , wherein the indication comprises a starting location of the set of RACH resources and an ending location of the set of RACH resources. 
     
     
         12 . The method of  claim 8 , wherein the set of RACH resources comprises a number of the RACH resources that are contiguous in time or frequency. 
     
     
         13 . The method of  claim 8 , wherein the set of RACH resources is interlaced in time or frequency within a resource grid spanning a system bandwidth in frequency and at least one slot in time. 
     
     
         14 . The method of  claim 8 , wherein the msgA of the two-step RACH procedure is received from the UE, and multiple UEs share the set of RACH resources in a time and frequency domain. 
     
     
         15 . An apparatus for wireless communication, comprising:
 a memory; and   at least one processor coupled to the memory and configured to:
 receive, from a base station, an indication of resources in time and frequency allocated for random access channel (RACH) communication with the base station, wherein the indication of resources comprises a set of RACH resources, wherein the set of RACH resources is mapped to a time frequency resource grid with respect to a synchronization signal block (SSB) based on at least one of a center frequency of a RACH resource or a number of physical resource blocks (PRBs) within each RACH resource in the set of RACH resources, wherein the indication of resources is based on a mapping index for the set of RACH resources mapped to the time frequency resource grid and indexed in a sequential order, wherein the mapping index maps at least one of the set of RACH resources to the time frequency resource grid; and 
 transmit, to the base station, a message A (msgA) of a two-step RACH procedure based on the indication of resources received from the base station. 
   
     
     
         16 . The apparatus of  claim 15 , wherein the indication of resources is based on a raster of candidate locations for the set of RACH resources. 
     
     
         17 . The apparatus of  claim 15 , wherein the indication comprises a starting location of the set of RACH resources and a number of the RACH resources comprised in the set of RACH resources. 
     
     
         18 . The apparatus of  claim 15 , wherein the indication comprises a starting location of the set of RACH resources and an ending location of the set of RACH resources. 
     
     
         19 . The apparatus of  claim 15 , wherein the set of RACH resources comprises a number of the RACH resources that are contiguous in time or frequency. 
     
     
         20 . The apparatus of  claim 15 , wherein the set of RACH resources is interlaced in time or frequency within a resource grid spanning a system bandwidth in frequency and at least one slot in time. 
     
     
         21 . The apparatus of  claim 15 , wherein the msgA of the two-step RACH procedure is transmitted to the base station, and multiple UEs share the set of RACH resources in a time and frequency domain. 
     
     
         22 . An apparatus for wireless communication, comprising:
 a memory; and   at least one processor coupled to the memory and configured to:
 transmit, to a user equipment (UE), an indication of resources in time and frequency allocated for random access channel (RACH) communication with the UE, wherein the indication of resources comprises a set of RACH resources, wherein the set of RACH resources is mapped to a time frequency resource grid with respect to a synchronization signal block (SSB) based on at least one of a center frequency of a RACH resource or a number of physical resource blocks (PRBs) within each RACH resource in the set of RACH resources, wherein the indication of resources is based on a mapping index for the set of RACH resources mapped to the time frequency resource grid and indexed in a sequential order, wherein the mapping index maps at least one of the set of RACH resources to the time frequency resource grid; and 
 receive, from the UE, a message A (msgA) of a two-step RACH procedure based on the indication of resources transmitted to the UE. 
   
     
     
         23 . The apparatus of  claim 22 , wherein the indication of resources is based on a raster of candidate locations for the set of RACH resources. 
     
     
         24 . The apparatus of  claim 22 , wherein the indication comprises a starting location of the set of RACH resources and a number of the RACH resources comprised in the set of RACH resources. 
     
     
         25 . The apparatus of  claim 22 , wherein the indication comprises a starting location of the set of RACH resources and an ending location of the set of RACH resources. 
     
     
         26 . The apparatus of  claim 22 , wherein the set of RACH resources comprises a number of the RACH resources that are contiguous in time or frequency. 
     
     
         27 . The apparatus of  claim 22 , wherein the set of RACH resources is interlaced in time or frequency within a resource grid spanning a system bandwidth in frequency and at least one slot in time. 
     
     
         28 . The apparatus of  claim 22 , wherein the msgA of the two-step RACH procedure is received from the UE, and multiple UEs share the set of RACH resources in time and frequency domain.