Method and apparatus for multistream transmission

Abstract

Methods and apparatuses for multistream transmissions are provided. A user equipment (UE) includes a transceiver configured to receive an L-layer data transmission that includes at least one codeblock (CB). The CB includes a length-N cyclic redundancy code (CRC). The transceiver is also configured to receive a downlink control information (DCI) associated with the data transmission. The UE further includes a processor operably connected to the transceiver. The processor is configured to decode the data transmission, the CRC, and the DCI. The data transmission includes one codeword (CW) when L is less than or equal to a threshold and two CWs when L is greater than the threshold.

What is claimed: 
     
         1 . A user equipment (UE) comprising:
 a transceiver configured to:
 receive an L-layer data transmission, wherein the data transmission includes at least one codeblock (CB) and the CB includes a length-N cyclic redundancy code (CRC); 
 receive a downlink control information (DCI) associated with the data transmission; and 
   a processor operably connected to the transceiver, the processor configured to decode the data transmission, the CRC, and the DCI,   wherein the data transmission includes one codeword (CW) when L is less than or equal to a threshold and two CWs when L is greater than the threshold.   
     
     
         2 . The UE of  claim 1 , wherein the threshold is fixed to four. 
     
     
         3 . The UE of  claim 2 , wherein the DCI includes one modulation and coding scheme (MCS) field when L is less than or equal to 4 and two MCS fields when L is greater than 4. 
     
     
         4 . The UE of  claim 2 , wherein:
 the processor is further configured to generate at least one channel quality indicator (CQI), and   the transceiver is further configured to transmit the at least one CQI via an uplink channel.   
     
     
         5 . The UE of  claim 4 , wherein the at least one CQI is one CQI when L is less than or equal to 4 and two CQIs when L is greater than 4. 
     
     
         6 . The UE of  claim 2 , wherein a length of the CRC is a function of a length of the CB and the length of the CRC corresponds to a number of bits. 
     
     
         7 . The UE of  claim 2 , wherein modulated symbols in the one CW or the two CWs of the data transmission are first mapped across layers associated with the one CW or the two CWs, then mapped across frequency sub-carriers, and then mapped across OFDM symbols. 
     
     
         8 . A base station (BS) comprising:
 a processor configured to:
 generate an L-layer data transmission for a user equipment (UE); 
 generate a downlink control information (DCI) associated with the data transmission; 
   wherein the data transmission includes at least one codeblock (CB) and the CB includes a length-N cyclic redundancy code (CRC); and   a transceiver operably connected to the processor, the transceiver configured to transmit the data transmission and the DCI,   wherein the data transmission includes one codeword (CW) when L is less than or equal to a threshold and two CWs when L is greater than the threshold.   
     
     
         9 . The BS of  claim 8 , wherein the threshold is fixed to four. 
     
     
         10 . The BS of  claim 9 , wherein the DCI includes one modulation and coding scheme (MCS) field when L is less than or equal to 4 and two MCS fields when L is greater than 4. 
     
     
         11 . The BS of  claim 9 , wherein:
 the processor is further configured to receive and decode at least one channel quality indicator (CQI) via an uplink channel, and   the at least one CQI is one CQI is one when L is less than or equal to 4 and two CQIs when L is greater than 4.   
     
     
         12 . The BS of  claim 9 , wherein a length of the CRC is a function of a length of the CB and the length of the CRC corresponds to a number of bits. 
     
     
         13 . The BS of  claim 9 , wherein modulated symbols in the one CW or the two CWs of the data transmission are first mapped across layers associated with the one CW or the two CWs, then mapped across frequency sub-carriers, and then mapped across OFDM symbols. 
     
     
         14 . A method for operating a user equipment (UE), the method comprising:
 receiving an L-layer data transmission, wherein the data transmission includes at least one codeblock (CB) and the CB includes a length-N cyclic redundancy code (CRC);   receiving a downlink control information (DCI) associated with the data transmission; and   decoding the data transmission, the CRC, and the DCI;   wherein the data transmission includes one codeword (CW) when L is less than or equal to a threshold and two CWs when L is greater than the threshold.   
     
     
         15 . The method of  claim 14 , wherein the threshold is fixed to four. 
     
     
         16 . The method of  claim 15 , wherein the DCI includes one modulation and coding scheme (MCS) field when L is less than or equal to 4 and two MCS fields when L is greater than 4. 
     
     
         17 . The method of  claim 15 , further comprising:
 generating at least one channel quality indicator (CQI); and   transmitting the at least one CQI via an uplink channel.   
     
     
         18 . The method of  claim 17 , wherein the at least one CQI is one CQI when L is less than or equal to 4 and two CQIs when L is greater than 4. 
     
     
         19 . The method of  claim 15 , wherein a length of the CRC is a function of a length of the CB and the length of the CRC corresponds to a number of bits. 
     
     
         20 . The method of  claim 15 , wherein modulated symbols in the one CW or the two CWs of the data transmission are first mapped across layers associated with the one CW or the two CWs, then mapped across frequency sub-carriers, and then mapped across OFDM symbols.