Method and apparatus in relaying system

1. An apparatus, comprising:

a channel estimator configured to estimate channel coefficients of communication channels of multiple-input-multiple-output communication;

a precoder configured to apply the estimated channel coefficients to precode a transmit signal to cancel impact of the communication channels on the transmit signal;

a first controller configured to provide the precoded transmit signal for multiple-input-multiple-output transmission in a first timeslot;

a second controller configured to process a multiple-input-multiple-output receive signal received in a second timeslot following the first timeslot; and

a cancellator configured to cancel the transmit signal from the receive signal,

wherein the first controller is configured to provide the transmit signal for transmission via a first radio antenna, and a negation of the transmit signal for transmission via a second transmit antenna, and

wherein the second controller is configured to process receive signals received via two radio antennas, the apparatus comprising a signal estimator configured to estimate a received signal, the signal estimator being, in estimation of the received signal, configured to:

form a difference of receive signals received via the two radio antennas;

multiply the difference by one divided by the square-root of two.

2. An apparatus according to claim 1 , wherein the estimator is configured to estimate the channel coefficients on the basis of a receive signal received in a receive duplex of a time division duplex frame.

3. An apparatus according to claim 1 , wherein the precoder is configured to precode at least two transmit signals each targeting to a different receiving station, wherein the cancellator is configured to cancel the at least two transmit signals from the receive signal.

4. An apparatus according to claim 1 , comprising a signal estimator configured to estimate one or more received signals from the receive signal from which the transmit signal has been cancelled.

5. A transceiver comprising an apparatus according to claim 1 , comprising:

at least two radio antennas;

a transmitter configured to transmit the transmit signal via each of the at least two radio antennas;

a receiver configured to receive a receive signal via the at least two radio antennas; and

wherein the cancellator is configured to cancel the transmit signal from each receive signal received via each of the at least two radio antennas.

6. An apparatus according to claim 1 , comprising a transceiver configured to transmit the transmit signal and receive the receive signal from a relay station of a relaying system.

7. An apparatus according to claim 1 , wherein the apparatus is one of a mobile station or a base station.

8. An apparatus, comprising:

a channel estimator configured to estimate channel coefficients of communication channels of multiple-input-multiple-output communication;

a precoder configured to apply the estimated channel coefficients to precode a transmit signal to cancel impact of the communication channels on the transmit signal;

a first controller configured to provide the precoded transmit signal for multiple-input-multiple-output transmission in a first timeslot;

a second controller configured to process a multiple-input-multiple-output receive signal received in a second timeslot following the first timeslot; and

a cancellator configured to cancel the transmit signal from the receive signal,

wherein the precoder is configured to precode at least two transmit signals each targeting to a different receiving station, and

wherein the second controller is configured to process receive signals received via two radio antennas, the apparatus comprising a signal estimator configured to estimate two received signals each transmitted by different stations, the signal estimator being, in estimation of the received signals, configured to in estimation of the first received signal:

form a sum of the receive signals received via the two radio antennas;

multiply the sum by one divided by two;

and in estimation of the second received signal:

form a difference of the receive signals received via the two radio antennas; and

multiply the difference by one divided by the square-root of two.

9. An apparatus according to claim 8 , wherein the estimator is configured to estimate the channel coefficients on the basis of a receive signal received in a receive duplex of a time division duplex frame.

10. An apparatus according to claim 8 , wherein the precoder is configured to precode at least two transmit signals each targeting to a different receiving station, wherein the cancellator is configured to cancel the at least two transmit signals from the receive signal.

11. An apparatus according to claim 8 , comprising a signal estimator configured to estimate one or more received signals from the receive signal from which the transmit signal has been cancelled.

12. A transceiver comprising an apparatus according to claim 8 , comprising:

at least two radio antennas;

a transmitter configured to transmit the transmit signal via each of the at least two radio antennas;

a receiver configured to receive a receive signal via the at least two radio antennas; and

wherein the cancellator is configured to cancel the transmit signal from each receive signal received via each of the at least two radio antennas.

13. An apparatus according to claim 8 , comprising a transceiver configured to transmit the transmit signal and receive the receive signal from a relay station of a relaying system.

14. An apparatus according to claim 8 , wherein the apparatus is one of a mobile station or a base station.