Precoding and feedback channel information in wireless communication system
The present invention relates to precoding and feedback channel information in wireless communication system. A method includes receiving a first Precoding Matrix Index (PMI) and a second PMI from a terminal; mapping one or two codewords into layers; precoding symbols mapped into the layers using a first precoding matrix derived from the first PMI and a second precoding matrix derived from the second PMI; and transmitting the precoded symbols to the terminal, wherein the reception of the first PMI is less frequent than the reception of the second PMI.
1. A communication method comprising:
estimating a downlink channel based on a signal received from a base station;
transmitting a first-type precoding matrix index (PMI) to the base station;
transmitting a second-type PMI to the base station; and
receiving a downlink signal from the base station,
decoding the received downlink signal based on the first-type PMI and the second-type PMI,
wherein transmitting the first-type PMI is periodically performed based on a first period, and transmitting the second-type PMI is periodically performed based on a second period.
2. The method of claim 1 , wherein the first period is shorter than the second period.
3. The method of claim 1 , wherein the second period is a multiple of the first period.
4. The method of claim 3 , further comprising decoding the received-downlink signal based on the first-type PMI and the second-type PMI.
5. A mobile terminal comprising:
a processor; and
a memory operably coupled to the processor,
wherein the processor, when executing program instructions stored in the memory, is configured to:
cause the mobile terminal to estimate a downlink channel based on a signal received from a base station;
cause the mobile terminal to transmit a first-type precoding matrix index (PMI) to the base station;
cause the mobile terminal to transmit a second-type PMI to the base station; and
cause the mobile terminal to receive a downlink signal from the base station,
cause the mobile terminal to decode the received downlink signal based on the first-type PMI and the second-type PMI;
wherein the processor is further configured to cause the mobile terminal to transmit the first-type PMI periodically based on a first period, and cause the mobile terminal to transmit the second-type PMI periodically based on a second period.
6. The mobile terminal of claim 5 , wherein the first period is shorter than the second period.
7. The mobile terminal of claim 5 , wherein the second period is a multiple of the first period.
8. The mobile terminal of claim 7 , wherein the processor is further configured to decode the received downlink signal based on the first-type PMI and the second-type PMI.
9. A device for a mobile terminal, the device comprising:
a processor; and
a memory operably coupled to the processor,
wherein the processor, when executing program instructions stored in the memory, is configured to:
cause the mobile terminal to estimate a downlink channel based on a signal received from a base station;
cause the mobile terminal to transmit a first-type precoding matrix index (PMI) to the base station;
cause the mobile terminal to transmit a second-type PMI to the base station; and
cause the mobile terminal to receive a downlink signal from the base station,
cause the mobile terminal to decode the received downlink signal based on the first-type PMI and the second-type PMI;
wherein the processor is further configured to cause the mobile terminal to transmit the first-type PMI periodically based on a first period, and cause the mobile terminal to transmit the second-type PMI periodically based on a second period.
10. The device of claim 9 , wherein the first period is shorter than the second period.
11. The device of claim 9 , wherein the second period is a multiple of the first period.
12. The device of claim 11 , wherein the processor is further configured to decode the received downlink signal based on the first-type PMI and the second-type PMI.