Method of and apparatus for mapping to demodulation reference signal port
View Patent ↗A demodulation reference signal port mapping method is disclosed. The method includes: a base station communicates with a User Equipment (UE), and allocates corresponding data stream to the UE according to the attribution of the UE; the base station maps the corresponding data stream from a layer to a corresponding demodulation reference signal port; the base station transmits the corresponding data stream to the UE via demodulation reference signal port. By restricting the demodulation reference signal port mapping solution of rank=1 to rank=8 and the demodulation reference signal port mapping solution when the retransmission occurs, the technical solution enables the demodulation reference signal port mapping solution to be compatible with the present system and to keep lower overhead of the demodulation reference signal.
1. A method of mapping to a demodulation reference signal port, comprising:
assigning, by a base station, a User Equipment, UE, with a corresponding data stream dependent upon an attribute of the UE;
mapping, by the base station, the corresponding data stream from a layer to a corresponding demodulation reference signal port dependent upon a value of a rank; and
transmitting, by the base station, the corresponding data stream to the UE via the demodulation reference signal port;
wherein for downlink transmission at the rank=2, mapping, by the base station, the corresponding data stream from the layer to the corresponding demodulation reference signal port comprises: when downlink transmission is double-codeword transmission at the rank=2, the base station maps two layers to two demodulation reference signal ports belonging to a same code division multiplexing (CDM) group.
2. The method of mapping to a demodulation reference signal port according to claim 1 , wherein for downlink transmission at the rank=1, mapping, by the base station, the corresponding data stream from a layer to a corresponding demodulation reference signal port comprises:
mapping the corresponding data stream onto any port and occupying any CDM group.
3. The method of mapping to a demodulation reference signal port according to claim 1 , wherein for retransmission of the same codeword corresponding to the two layers, it is retransmitted in single-codeword transmission, and the ports occupied for the two layers in retransmission belong to the same CDM group.
4. The method of mapping to a demodulation reference signal port according to claim 1 , wherein for downlink transmission at the rank=3 or the rank=4, mapping, by the base station, the corresponding data stream from a layer to a corresponding demodulation reference signal port comprises:
when downlink transmission is double-codeword transmission, mapping the layer, to which a codeword 1 corresponds, to a first demodulation reference signal CDM group, and mapping the layer, to which a codeword 2 corresponds, to a second demodulation reference signal CDM group; and
when downlink transmission is single-codeword transmission, keeping layer-to-demodulation reference signal port mapping consistent with double-codeword transmission.
5. The method of mapping to a demodulation reference signal port according to claim 4 , wherein when downlink transmission is double-codeword transmission at the rank=3, if one of the codewords has an error occurring therewith and will be retransmitted and the other codeword has no new data to be transmitted, then a mapping relationship between the layer to which the retransmitted codeword corresponds and the occupied port thereof is defined as that at the rank=1 or the rank=2.
6. The method of mapping to a demodulation reference signal port according to claim 4 , wherein when downlink transmission is double-codeword transmission at the rank=4, if one of the codewords has an error occurring therewith and will be retransmitted and the other codeword has no new data to be transmitted, then a mapping relationship between the layer to which the retransmitted codeword corresponds and the occupied port thereof is defined as that at the rank=2.
7. The method of mapping to a demodulation reference signal port according to claim 1 , wherein for downlink transmission at the rank=5, the rank=6, the rank=7 or the rank=8, mapping, by the base station, the corresponding data stream from a layer to a corresponding demodulation reference signal port comprises:
mapping the layer, to which a codeword 1 corresponds, to a first demodulation reference signal CDM group, and mapping the layer, to which a codeword 2 corresponds, to a second demodulation reference signal CDM group.
8. The method of mapping to a demodulation reference signal port according to claim 7 , wherein when downlink transmission is double-codeword transmission at the rank=5, if one of the codewords has an error occurring therewith and will be retransmitted and the other codeword has no new data to be transmitted, then a mapping relationship between the layer to which the retransmitted codeword corresponds and the occupied port thereof is defined as that at the rank=2 or the rank=3.
9. The method of mapping to a demodulation reference signal port according to claim 7 , wherein when downlink transmission is double-codeword transmission at the rank=6, if one of the codewords has an error occurring therewith and will be retransmitted and the other codeword has no new data to be transmitted, then a mapping relationship between the layer to which the retransmitted codeword corresponds and the occupied port thereof is defined as that at the rank=3.
10. The method of mapping to a demodulation reference signal port according to claim 7 , wherein when downlink transmission is double-codeword transmission at the rank=7, if one of the codewords has an error occurring therewith and will be retransmitted and the other codeword has no new data to be transmitted, then a mapping relationship between the layer to which the retransmitted codeword corresponds and the occupied port thereof is defined as that at the rank=3 or the rank=4.
11. The method of mapping to a demodulation reference signal port according to claim 7 , wherein when downlink transmission is double-codeword transmission at the rank=8, if one of the codewords has an error occurring therewith and will be retransmitted and the other codeword has no new data to be transmitted, then a mapping relationship between the layer to which the retransmitted codeword corresponds and the occupied port thereof is defined as that at the rank=4.
12. A base station, comprising a transceiver and a processor, wherein:
the transceiver is configured to assign a User Equipment, UE, with a corresponding data stream dependent upon an attribute of the UE;
the processor is configured to map the corresponding data stream from a layer to a corresponding demodulation reference signal port dependent upon a value of a rank; and
the transceiver is further configured to transmit the corresponding data stream to the UE via the demodulation reference signal port;
wherein for downlink transmission at the rank=2, the processor mapping the corresponding data stream from a layer to a corresponding demodulation reference signal port comprises: when downlink transmission is double-codeword transmission at the rank=2, the processor maps two layers to two demodulation reference signal ports belonging to a same code division multiplexing (CDM) group.
13. The base station according to claim 12 , wherein for downlink transmission at the rank=1, the processor mapping the corresponding data stream from a layer to a corresponding demodulation reference signal port comprises:
mapping the corresponding data stream onto any port and occupying any CDM group.
14. The base station according to claim 12 , wherein for retransmission of a codeword corresponding to the two layers, it is retransmitted in single-codeword transmission, and the ports occupied for the two layers in retransmission belong to the same CDM group.
15. The base station according to claim 12 , wherein for downlink transmission at the rank=3 or the rank=4, the processor mapping the corresponding data stream from a layer to a corresponding demodulation reference signal port comprises:
when downlink transmission is double-codeword transmission, mapping the layer, to which a codeword 1 corresponds, to a first demodulation reference signal CDM group, and mapping the layer, to which a codeword 2 corresponds, to a second demodulation reference signal CDM group; and
when downlink transmission is single-codeword transmission, keeping layer-to-demodulation reference signal port mapping consistent with double-codeword transmission,
wherein when downlink transmission is double-codeword transmission at the rank=3, if one of the codewords has an error occurring therewith and will be retransmitted and the other codeword has no new data to be transmitted, then a mapping relationship between the layer to which the retransmitted codeword corresponds and the occupied port thereof is defined as that at the rank=1 or the rank=2; or
when downlink transmission is double-codeword transmission at the rank=4, if one of the codewords has the error occurring therewith and will be retransmitted and the other codeword has no new data to be transmitted, then the mapping relationship between the layer to which the retransmitted codeword corresponds and the occupied port thereof is defined as that at the rank=2.
16. The base station according to claim 12 , wherein for downlink transmission at the rank=5, the rank=6, the rank=7 or the rank=8, the processor mapping the corresponding data stream from a layer to a corresponding demodulation reference signal port comprises:
mapping the layer, to which a codeword 1 corresponds, to a first demodulation reference signal CDM group, and mapping the layer, to which a codeword 2 corresponds, to a second demodulation reference signal CDM group,
wherein when downlink transmission is double-codeword transmission at the rank=5, if one of the codewords has an error occurring therewith and will be retransmitted and the other codeword has no new data to be transmitted, then a mapping relationship between the layer to which the retransmitted codeword corresponds and the occupied port thereof is defined as that at the rank=2 or the rank=3; or
when downlink transmission is double-codeword transmission at the rank=6, if one of the codewords has the error occurring therewith and will be retransmitted and the other codeword has no new data to be transmitted, then the mapping relationship between the layer to which the retransmitted codeword corresponds and the occupied port thereof is defined as that at the rank=3; or
when downlink transmission is double-codeword transmission at the rank=7, if one of the codewords has the error occurring therewith and will be retransmitted and the other codeword has no new data to be transmitted, then the mapping relationship between the layer to which the retransmitted codeword corresponds and the occupied port thereof is defined as that at the rank=3 or the rank=4; or
when downlink transmission is double-codeword transmission at the rank=8, if one of the codewords has the error occurring therewith and will be retransmitted and the other codeword has no new data to be transmitted, then the mapping relationship between the layer to which the retransmitted codeword corresponds and the occupied port thereof is defined as that at the rank=4.