Method and apparatus for using channel output feedback in multi user wireless systems and hybrid-ARQ

1. A terminal for transmitting a signal using a channel output feedback, the terminal comprising:

a transmitter configured to transmit, to a base station, a first packet being applied a precoder received from the base station;

a receiver configured to receive, from the base station, a Channel Output Feedback (COF) of the transmitted first packet and information for transmitting a second packet, wherein the information for transmitting the second packet is information on a channel state between the terminal and the base station determined based on a channel output of the transmitted first packet; and

a controller configured to prepare a variant of the second packet using the COF and the received information for transmitting the second packet, and to control to transmit the prepared variant to the base station,

wherein the COF of the transmitted first packet is a received signal of first packet received by the base station.

2. The terminal of claim 1 , wherein the information for transmitting the second packet includes at least one of information for a first precoder of a signal transmitted over a current time, information for a second precoder of a signal transmitted over a previous time, a first scalar coefficient for the first precoder and a second scalar coefficient for the second precoder.

3. The terminal of claim 1 , wherein the COF is transmitted via one of a Physical Downlink Shared Channel (PDSCH) and a Physical Downlink Control Channel (PDCCH).

4. The method of claim 1 , wherein the transmitter is configured to transmit a pilot signal to the base station, wherein the precoder is selected based on the transmitted pilot signal.

5. A method for transmitting a signal using a channel output feedback in a terminal, the method comprising:

receiving information for a precoder from the base station;

transmitting a first packet being applied the received precoder to the base station;

receiving a Channel Output Feedback (COF) of the transmitted first packet from the base station;

receiving information for transmitting a second packet from the base station, wherein the information for transmitting the second packet is information on a channel state between the terminal and the base station determined based on a channel output of the transmitted first packet;

preparing a variant of the second packet using the COF and the received information for transmitting the second packet; and

transmitting the prepared variant to the base station,

wherein the COF of the transmitted first packet is a received signal of first packet received by the base station.

6. The method of claim 5 , wherein the information for transmitting the second packet includes at least one of information for a first precoder of a signal transmitted over a current time, information for a second precoder of a signal transmitted over a previous time, a first scalar coefficient for the first precoder and a second scalar coefficient for the second precoder.

7. The method of claim 5 , wherein the COF is transmitted via one of a Physical Downlink Shared Channel (PDSCH) and a Physical Downlink Control Channel (PDCCH).

8. The method of claim 5 , further comprising:

transmitting a pilot signal to the base station,

wherein the precoder is selected based on the transmitted pilot signal.

9. A base station for receiving a signal using a channel output feedback, the base station comprising:

a transmitter configured to transmit, to a terminal, information for a precoder;

a receiver configured to receive, from the terminal, a first packet being applied on the transmitted precoder; and

a controller configured to control to feed back a channel output of the received first packet, to determine information for transmitting a second packet which is information on a channel state between the terminal and the base station based on the channel output, to control to transmit the determined information for transmitting a second packet to the terminal, and to control to receive a second packet from the terminal, wherein the second packet is a variant of an original signal prepared using the COF and the transmitted information for transmitting the second packet,

wherein the COF of the transmitted first packet is a received signal of first packet received by the base station.

10. The base station of claim 9 , wherein the receiver receives information for another base station from the other base station and the information for transmitting the second packet is determined based on further the received information for the other base station.

11. The base station of claim 9 , wherein the receiver is configured to receive a first pilot signal from the terminal and a second pilot signal from another terminal,

wherein the transmitter is configured to transmit information for the base station to other base station, and

wherein the information for the base station is trained based on the first and second pilot signal.

12. The base station of claim 9 , wherein the receiver receives a first pilot signal from the terminal and a second pilot signal from another terminal, wherein the precoder is selected based on the first and second pilot signal.

13. The base station of claim 9 , wherein the information for transmitting the second packet includes at least one of information for a first precoder of a signal transmitted over a current time, information for a second precoder of a signal transmitted over a previous time, a first scalar coefficient for the first precoder and a second scalar coefficient for the second precoder.

14. The base station of claim 9 , wherein the COF is transmitted via one of a Physical Downlink Shared Channel (PDSCH) and a Physical Downlink Control Channel (PDCCH).

15. A method for receiving a signal using a channel output feedback in a base station, the method comprising:

transmitting information for a precoder to a terminal;

receiving a first packet being applied on the transmitted precoder from the terminal;

feeding back a channel output of the received first packet to the terminal;

determining information for transmitting a second packet which is information on a channel state between the terminal and the base station based on the channel output;

transmitting the determined information for transmitting a second packet to the terminal; and

receiving a second packet from the terminal, wherein the second packet is a variant of an original signal prepared using the COF and the transmitted information for transmitting the second packet,

wherein the COF of the transmitted first packet is a received signal of first packet received by the base station.

16. The method of claim 15 , further comprising:

receiving information for another base station from the other base station,

wherein the information for transmitting the second packet is determined based on further the received information for the other base station.

17. The method of claim 15 , further comprising:

receiving a first pilot signal from the terminal;

receiving a second pilot signal from another terminal; and

transmitting information for the base station to other base station,

wherein the information for the base station is trained based on the first and second pilot signal.

18. The method of claim 15 , further comprising:

receiving a first pilot signal from the terminal; and

receiving a second pilot signal from another terminal,

wherein the precoder is selected based on the first and second pilot signal.

19. The method of claim 15 , wherein the information for transmitting the second packet includes at least one of information for a first precoder of a signal transmitted over a current time, information for a second precoder of a signal transmitted over a previous time, a first scalar coefficient for the first precoder and a second scalar coefficient for the second precoder.

20. The method of claim 15 , wherein the COF is transmitted via one of a Physical Downlink Shared Channel (PDSCH) and a Physical Downlink Control Channel (PDCCH).