Method for transmitting a reference signal, method for determining phase noise and related apparatuses
The present invention relates to the field of wireless communications, and in particular, to a method for transmitting a reference signal, a method for determining a phase noise, and related apparatuses, to resolve the problem in the prior art that different phase noises of different antenna units or antenna ports of a transmitter cannot be accurately estimated and compensated for. The method comprises: the transmitter respectively transmitting each precoded DMRS and PTRS to a receiver via respective corresponding antenna groups having a same phase noise, and when the receiver receives the PTRS, performing channel estimation based on each received PTRS, to determine phase changes caused by phase noises corresponding to different antenna groups. In this way, even if different antennas of a transmitter have different phase noises, phase changes caused by the different phase noises can still be accurately determined, so that all data transmitted by the different antenna groups can be accurately demodulated according to different phase changes.
1. A method for transmitting a reference signal, comprising:
pre-coding, by a transmitter, each data stream, and transmitting each data stream over its corresponding one or more antenna groups, wherein antenna elements or antenna ports in a same antenna group have a same phase noise, and all antenna groups corresponding to one data stream have a same phase noise;
pre-coding, by the transmitter, a Demodulation Reference Signal (DMRS) of each DMRS port, and transmitting each DMRS over its corresponding one or more antenna groups, wherein all antenna groups corresponding to one DMRS port have a same phase noise, and one data stream corresponds to one DMRS port; and
pre-coding, by the transmitter, a Phase-Tracking Reference Signal (PTRS) of each PTRS port, and transmitting each PTRS over its corresponding one or more antenna groups, wherein all antenna groups corresponding to one PTRS port have a same phase noise, and one PTRS port corresponds to at least one DMRS port.
2. The method according to claim 1 , wherein: the transmitter pre-codes a data stream in such a way that weights for antenna elements or antenna ports in the other antenna groups than an antenna group corresponding to the data stream are zero;
the transmitter pre-codes a DMRS in such a way that weights for antenna elements or antenna ports in the other antenna groups than an antenna group corresponding to the DMRS are zero; and
the transmitter pre-codes a PTRS in such a way that weights for antenna elements or antenna ports in the other antenna groups than an antenna group corresponding to the PTRS are zero.
3. The method according to claim 1 , further comprising:
determining, by the transmitter, a first mapping relationship between the respective PTRS ports and the respective DMRS ports, wherein in the first mapping relationship, one PTRS port is mapped to at least one DMRS port, and the PTRS port and its mapped DMRS port use a same antenna group for transmission.
4. The method according to claim 3 , further comprising:
transmitting, by the transmitter, the first mapping relationship to a receiver after determining the first mapping relationship; or
pre-agreeing, by the transmitter, with a receiver on the first mapping relationship;
wherein transmitting, by the transmitter, the first mapping relationship to the receiver comprises:
transmitting, by the transmitter, the first mapping relationship to the receiver via higher-layer signaling; or
transmitting, by the transmitter, the first mapping relationship to the receiver via dynamic control signaling.
5. The method according to claim 1 , further comprising:
determining, by the transmitter, a second mapping relationship between the respective data streams to be transmitted and the respective DMRS ports, wherein in the second mapping relationship, one data stream is mapped to one DMRS port, and the data stream and its mapped DMRS port correspond to a same antenna group for transmission.
6. The method according to claim 5 , further comprising:
transmitting, by the transmitter, the second mapping relationship to a receiver after determining the second mapping relationship; or
pre-agreeing, by the transmitter, with a receiver on the second mapping relationship;
wherein transmitting, by the transmitter, the second mapping relationship to the receiver comprises:
transmitting, by the transmitter, the second mapping relationship to the receiver via higher-layer signaling; or
transmitting, by the transmitter, the second mapping relationship to the receiver via dynamic control signaling.
7. The method according to claim 1 , wherein precoder used by the transmitter for a PTRS is the same as precoder used by a data stream over a sub-carrier occupied by the PTRS, said data stream corresponds to a DMRS port corresponding to the PTRS.
8. An apparatus for transmitting a reference signal, comprising: a processor, a transceiver, and a memory, wherein:
the processor is configured to read and execute program in the memory: to transmit data streams, Demodulation Reference Signals (DMRSs), and Phase-Tracking Reference Signals (PTRSs) through the transceiver; to pre-code each data stream, and then transmit each data stream over its corresponding one or more antenna groups, wherein antenna elements or antenna ports in a same antenna group have a same phase noise, and all antenna groups corresponding to one data stream have a same phase noise; to pre-code a DMRS of each DMRS port, and transmit each DMRS over its corresponding one or more antenna groups, wherein all antenna groups corresponding to one DMRS port have a same phase noise, and one data stream corresponds to one DMRS port; and to pre-code a PTRS of each PTRS port, and transmit each PTRS over its corresponding one or more antenna groups, wherein all antenna groups corresponding to one PTRS port have a same phase noise, and one PTRS port corresponds to at least one DMRS port; and
the transceiver is configured to transmit and receive data under a control of the processor.
9. The apparatus according to claim 8 , wherein the processor is configured:
to pre-code a data stream in such a way that weights for antenna elements or antenna ports in the other antenna groups than an antenna group corresponding to the data stream are zero;
to pre-code a DMRS in such a way that weights for antenna elements or antenna ports in the other antenna groups than an antenna group corresponding to the DMRS are zero; and
to pre-code a PTRS in such a way that weights for antenna elements or antenna ports in the other antenna groups than an antenna group corresponding to the PTRS are zero.
10. The apparatus according to claim 8 , wherein the processor is configured:
to determine a first mapping relationship between the respective PTRS ports and the respective DMRS ports, wherein in the first mapping relationship, one PTRS port is mapped to at least one DMRS port, and the PTRS port and its mapped DMRS port use a same antenna group for transmission.
11. The apparatus according to claim 10 , wherein the processor is configured:
to transmit the first mapping relationship to a receiver after determining the first mapping relationships; or
to pre-agree with a receiver on the first mapping relationship;
wherein the processor configured to transmit the first mapping relationship to the receiver is configured:
to transmit the first mapping relationship to the receiver via higher-layer signaling; or
to transmit the first mapping relationship to the receiver via dynamic control signaling.
12. The apparatus according to claim 8 , wherein the processor is configured:
to determine a second mapping relationship between the respective data streams to be transmitted and the respective DMRS ports, wherein in the second mapping relationship, one data stream is mapped to one DMRS port, and the data stream and its mapped DMRS port correspond to a same antenna group for transmission.
13. The apparatus according to claim 12 , wherein the processor is configured:
to transmit the second mapping relationship to a receiver after determining the second mapping relationship; or
to pre-agree with a receiver on the second mapping relationship;
wherein the processor configured to transmit the second mapping relationship to the receiver:
to transmit the second mapping relationship to the receiver via higher-layer signaling; or
to transmit the second mapping relationship to the receiver via dynamic control signaling.
14. The apparatus according to claim 8 , wherein precoder used by the processor for a PTRS is the same as precoder used by a data stream over a sub-carrier occupied by the PTRS, said data stream corresponds to a DMRS port corresponding to the PTRS.