Non-Orthogonal Multiple Access Wireless Communications Methods And Apparatus Thereof

Abstract

Various novel concepts and schemes pertaining to non-orthogonal multiple access for wireless communications are described. A group orthogonal coded access (GOCA) scheme is introduced to reduce multi-user interference (MUI) and improve performance. A repetition division multiple access (RDMA) scheme is introduced to differentiate user equipment (UEs) by different repetition patterns. A low-density spreading (LDS) scheme is introduced to reduce MUI and improve performance.

What is claimed is: 
     
         1 . A method, comprising:
 encoding, by a processor of a user equipment (UE) of a plurality of UEs, data for non-orthogonal multiple access (NOMA), the encoding comprising spreading the data into shared resources using a low-density spreading (LDS) pattern which is less than an entire pattern of the shared resources; and   transmitting, by the processor, the encoded data to a wireless receiver.   
     
     
         2 . The method of  claim 1 , wherein the LDS pattern is centralized within one or more portions of the entire pattern of the shared resources. 
     
     
         3 . The method of  claim 1 , wherein the LDS pattern is distributed across the entire pattern of the shared resources. 
     
     
         4 . The method of  claim 1 , wherein the encoding further comprises processing the data using a NOMA scheme in spreading the data into the shared resources with the LDS pattern. 
     
     
         5 . The method of  claim 4 , wherein the processing of the data using the NOMA scheme in spreading the data into the shared resources with the LDS pattern comprises processing the data using a repetition division multiple access (RDMA) scheme in spreading the data into the shared resources using the LDS pattern, wherein the RDMA scheme comprises spreading the data into the shared resources using a repetition pattern of a plurality of data pieces of the data. 
     
     
         6 . The method of  claim 5 , wherein the spreading of the data into the shared resources using the repetition pattern of the plurality of data pieces of the data comprises:
 allocating the plurality of data pieces of the data to a first portion of shared time and frequency resources; and   allocating a predefined number of repetitions of the plurality of data pieces of the data to a second portion of the shared time and frequency resources,   wherein each repetition of the predefined number of repetitions differs from the data pieces allocated to the first portion of the shared time and frequency resources by a respective amount of shift in time or frequency, and   wherein the respective amount of shift in time or frequency of a first repetition of the predefined number of repetitions for the UE is different from the respective amount of shift in time or frequency of a first repetition of the predefined number of repetitions for at least one other UE of the plurality of UEs.   
     
     
         7 . The method of  claim 6 , wherein the predefined number equals a spreading factor of the encoding. 
     
     
         8 . The method of  claim 5 , wherein the spreading of the data into the shared resources using the repetition pattern of the plurality of data pieces of the data comprises permutating the repetition pattern according to an equation as follows:
     d   ik   ≡P   i   −P   k =[ d   ik (0), d   ik (1), . . . , d   ik ( M   rep −1)] T ,
       d   ik ( m )≠ d   ik ( m ′) if  m≠m′,  
   wherein:
 M rep  denotes a number of permutations of the repetition pattern when there are L possible positions to choose from for a permutation and L Mrep  possible sequences for M rep  permutations for N ue  sequences to be drawn from the L Mrep  sequences for N ue  UEs, 
 P i  denotes a repetition pattern for an i th  UE, 
 P k  denotes repetition pattern for a k th  UE, 
 d ik (m) denotes a difference between an amount of shift in time or frequency of an m th  repetition of P i  and an amount of shift in time or frequency of an m th  repetition of P k , and 
 1<m<M rep . 
   
     
     
         9 . The method of  claim 5 , wherein the spreading of the data into the shared resources using the repetition pattern of the plurality of data pieces of the data comprises:
 performing a same permutation or different permutations on each of the data pieces in one or more repetitions; and   combining the permutated data pieces to generate the encoded data.