Methods and systems for conveying scheduling information of overlapping co-scheduled users in an ofdma-mu-mimo system

Abstract

A method implemented in a base station for conveying scheduling information in an orthogonal frequency division multiple access (OFDMA) multi-user (MU)-multiple input multiple output (MIMO) system is disclosed. The method includes transmitting to a first user equipment (UE) the scheduling information including first scheduling information of the first UE and at least a portion of second scheduling information of at least one second UE, wherein the scheduling information includes a resource block (RB) assigned to the first UE, the number of streams, and an indication of one or more dedicated reference symbol (RS) layers assigned to the first UE. Other methods, systems, and apparatuses also are disclosed.

What is claimed is: 
     
         1 . A method implemented in a base station for conveying scheduling information in an orthogonal frequency division multiple access (OFDMA) multi-user (MU)-multiple input multiple output (MIMO) system, the method comprising:
 transmitting to a first user equipment (UE) the scheduling information including first scheduling information of the first UE and at least a portion of second scheduling information of at least one second UE,   wherein the scheduling information includes a resource block (RB) assigned to the first UE, the number of streams, and an indication of one or more dedicated reference symbol (RS) layers assigned to the first UE.   
     
     
         2 . The method of  claim 1 ,
 wherein the second UE is an overlapping UE that is assigned at least one RB that overlaps with at least one RB assigned to the first UE,   wherein an RB is a set of subcarriers and orthogonal frequency-division multiplexing (OFDM) symbols.   
     
     
         3 . The method of  claim 1 ,
 wherein the scheduling information further includes modulation constellation of the second UE in case the number of streams is 2.   
     
     
         4 . The method of  claim 1 ,
 wherein the scheduling information further includes at least one of modulation constellation of the first UE, a coding rate of the first UE, a precoder matrix index (PMI) of the first UE, and a transmit power value of the first UE.   
     
     
         5 . The method of  claim 4 ,
 wherein at least one of the PMI and the transmit power value is transmitted to the first UE using dedicated reference symbol (RS) layers,   wherein each of the dedicated RS layers is precoded with a precoder and is transmitted on a portion of an RB.   
     
     
         6 . The method of  claim 1 ,
 wherein the indication of one or more dedicated RS layers comprises an allocated pilot stream index (PSI).   
     
     
         7 . The method of  claim 6 ,
 wherein at least part of the scheduling information is conveyed by a four-bit index that identifies the number of said streams and the PSI.   
     
     
         8 . The method of  claim 7 ,
 wherein said four-bit index further identifies a modulation constellation assigned to the second UE in case the number of streams is 2.   
     
     
         9 . A base station for conveying scheduling information in an orthogonal frequency division multiple access (OFDMA) multi-user (MU)-multiple input multiple output (MIMO) system, comprising:
 a transmission unit to transmit to a first user equipment (UE) the scheduling information including first scheduling information of the first UE and at least a portion of second scheduling information of at least one second UE,   wherein the scheduling information includes resource block (RB) assigned to the first UE, the number of streams, and an indication of one or more dedicated reference symbol (RS) layers assigned to the first UE.   
     
     
         10 . The base station of  claim 9 ,
 wherein the scheduling information further includes modulation constellation of the second UE in case the number of streams is 2.   
     
     
         11 . The base station of  claim 9 ,
 wherein the indication of one or more dedicated RS layers comprises an allocated pilot stream index (PSI).   
     
     
         12 . An orthogonal frequency division multiple access (OFDMA) multi-user (MU)-multiple input multiple output (MIMO) system for conveying scheduling information, comprising:
 a first user equipment (UE);   a second UE;   a base station configured to transmit to the first UE the scheduling information including first scheduling information of the first UE and at least a portion of second scheduling information of the second UE,   wherein the scheduling information includes resource block (RB) assigned to the first UE, the number of streams, and an indication of one or more dedicated reference symbol (RS) layers assigned to the first UE.   
     
     
         13 . The OFDMA MU-MIMO system of  claim 12 ,
 wherein the scheduling information further includes modulation constellation of the second UE in case the number of streams is 2.   
     
     
         14 . The OFDMA MU-MIMO system of  claim 12 ,
 wherein the indication of one or more dedicated RS layers comprises an allocated pilot stream index (PSI).   
     
     
         15 . A user equipment (UE) used in an orthogonal frequency division multiple access (OFDMA) multi-user (MU)-multiple input multiple output (MIMO) system conveying scheduling information from a base station, comprising:
 a receiving unit to receive the scheduling information including first scheduling information of the UE and at least a portion of second scheduling information of at least one second UE,   wherein the scheduling information includes resource block (RB) assigned to the UE, the number of streams, and an indication of one or more dedicated reference symbol (RS) layers assigned to the UE.   
     
     
         16 . The user equipment of  claim 15 ,
 wherein the scheduling information further includes modulation constellation of the second UE in case the number of streams is 2.   
     
     
         17 . The user equipment of  claim 15 ,
 wherein the indication of one or more dedicated RS layers comprises an allocated pilot stream index (PSI).