Method and device for performing channel estimation in wireless communication system
Provided are a method and device for performing channel estimation in a wireless communication system. Specifically, user equipment receives a control channel in the first symbol of a plurality of symbols received for a short TTI (sTTI) set to be shorter than a TTI. The user equipment receives a data channel scheduled by the control channel in the remaining symbols other than the first symbol of the plurality of symbols received in the sTTI. The user equipment receives a user equipment (UE)-specific reference signal having the same frequency resource as a first cell-specific reference signal received in the TTI in the first symbol. The first cell-specific reference signal is received subsequent to the UE-specific reference signal, and the UE-specific reference signal is received in the sTTI. The user equipment decodes the control channel or the data channel using the UE-specific reference signal.
1. A method for receiving, by a user equipment (UE), downlink signals in a wireless communication system using a subframe transmitted in a transmission time interval (TTI), the method comprising:
receiving a control channel in a first symbol of a plurality of symbols received in a short TTI (sTTI) set to be shorter than the TTI;
receiving a data channel scheduled by the control channel in remaining symbols other than the first symbol of the plurality of symbols received in the sTTI;
receiving, in the first symbol, a user equipment (UE)-specific reference signal having a frequency resource identical with a frequency resource of a first cell-specific reference signal received in the TTI, wherein the first cell-specific reference signal is received subsequent to the UE-specific reference signal, and wherein the UE-specific reference signal is received in the sTTI;
decoding the control channel or the data channel using the UE-specific reference signal, and
performing channel estimation on the control channel or the data channel through interpolation between the UE-specific reference signal and a second cell-specific reference signal received prior to the sTTI in which the UE-specific reference signal is received.
2. The method of claim 1 ,
wherein the second cell-specific reference signal is received in the TTI, and
wherein the second cell-specific reference signal has a frequency resource different from the frequency resource of the UE-specific reference signal.
3. The method of claim 2 , wherein the UE-specific reference signal is not received in a symbol in which the first cell-specific reference signal and the second cell-specific reference signal are received.
4. The method of claim 2 , wherein multiple input multiple output (MIMO) precoding is not applied to the first cell-specific reference signal, the second cell-specific reference signal, and the UE-specific reference signal.
5. The method of claim 1 , wherein transmission power for the UE-specific reference signal is identical with transmission power for the data channel.
6. The method of claim 1 , wherein:
the UE-specific reference signal is mapped to a first resource element using a first antenna port, and
transmission power for a UE-specific reference signal mapped to a second resource element using a second antenna port is set to zero.
7. A user equipment (UE) for receiving downlink signals in a wireless communication system using a subframe transmitted in a transmission time interval (TTI), the UE comprising:
a radio frequency (RF) unit that transmits and receives a radio signal; and
a processor connected to the RF unit, wherein the processor is configured to:
receive a control channel in a first symbol of a plurality of symbols received in a short TTI (sTTI) set to be shorter than the TTI;
receive a data channel scheduled by the control channel in remaining symbols other than the first symbol of the plurality of symbols received in the sTTI;
receive, in the first symbol, a user equipment (UE)-specific reference signal having a frequency resource identical with a frequency resource of a first cell-specific reference signal received in the TTI, wherein the first cell-specific reference signal is received subsequent to the UE-specific reference signal, and wherein the UE-specific reference signal is received in the sTTI;
decode the control channel or the data channel using the UE-specific reference signal, and
perform channel estimation on the control channel or the data channel through interpolation between the UE-specific reference signal and a second cell-specific reference signal received prior to the sTTI in which the UE-specific reference signal is received.
8. The UE of claim 7 ,
wherein the second cell-specific reference signal is received in the TTI, and
wherein the second cell-specific reference signal has a frequency resource different from the frequency resource of the UE-specific reference signal.
9. The UE of claim 8 , wherein the UE-specific reference signal is not received in a symbol in which the first cell-specific reference signal and the second cell-specific reference signal are received.
10. The UE of claim 8 , wherein multiple input multiple output (MIMO) precoding is not applied to the first cell-specific reference signal, the second cell-specific reference signal, and the UE-specific reference signal.
11. The UE of claim 7 , wherein transmission power for the UE-specific reference signal is identical with transmission power for the data channel.
12. The UE of claim 7 , wherein:
the UE-specific reference signal is mapped to a first resource element using a first antenna port, and
transmission power for a UE-specific reference signal mapped to a second resource element using a second antenna port is set to zero.
13. A method for transmitting, by a base station, downlink signals in a wireless communication system using a subframe transmitted in a transmission time interval (TTI), the method comprising:
transmitting a control channel in a first symbol of a plurality of symbols received in a short TTI (sTTI) set to be shorter than the TTI;
transmitting a data channel scheduled by the control channel in remaining symbols other than the first symbol of the plurality of symbols received in the sTTI;
transmitting, in the first symbol, a user equipment (UE)-specific reference signal having a frequency resource identical with a frequency resource of a first cell-specific reference signal received in the TTI, wherein the first cell-specific reference signal is transmitted subsequent to the UE-specific reference signal, and wherein the UE-specific reference signal is transmitted in the sTTI, and
performing channel estimation on the control channel or the data channel through interpolation between the UE-specific reference signal and a second cell-specific reference signal transmitted prior to the sTTI in which the UE-specific reference signal is transmitted.
14. The method of claim 13 , wherein:
the control channel or the data channel is decoded using the UE-specific reference signal,
the second cell-specific reference signal is transmitted in the TTI, and
the second cell-specific reference signal has a frequency resource different from the frequency resource of the UE-specific reference signal.
15. The method of claim 14 , wherein the UE-specific reference signal is not transmitted in a symbol in which the first cell-specific reference signal and the second cell-specific reference signal are transmitted.
16. The method of claim 14 , wherein multiple input multiple output (MIMO) precoding is not applied to the first cell-specific reference signal, the second cell-specific reference signal, and the UE-specific reference signal.
17. The method of claim 13 , wherein transmission power for the UE-specific reference signal is identical with transmission power for the data channel.
18. The method of claim 13 , wherein:
the UE-specific reference signal is mapped to a first resource element using a first antenna port, and
transmission power for a UE-specific reference signal mapped to a second resource element using a second antenna port is set to zero.