Self interference cancellation

1. A method performed under control of a first device capable of full duplex radio communications, the method comprising:

transmitting a first frame to a second device;

estimating a channel response of self interference cancellation (SIC), based, at least in part, on the first frame;

determining whether the estimated channel response is usable, based on determining whether a second frame is received from the second device in response to the transmission of the first frame;

responsive to a determination that the estimated channel response is usable, estimating a self interference, based, at least in part, on the usable estimated channel response; and

subtracting the estimated self interference from a signal to be received after the reception of the second frame.

2. The method of claim 1 , further comprising:

receiving the second frame from the second device within a predefined time after the transmission of the first frame,

wherein the determining whether the estimated channel response is usable includes determining that the estimated channel response is usable based on the reception of the second frame.

3. The method of claim 2 , further comprising:

updating the channel response of the SIC with the usable estimated channel response.

4. The method of claim 2 , wherein the transmitting the first frame to the second device includes transmitting at least one of a data frame or a probe request frame, and

wherein the receiving the second frame from the second device includes receiving at least one of an acknowledge (ACK) frame or a probe response frame.

5. The method of claim 1 , wherein the determining indicates that the estimated channel response is unusable, when the first device receives no frame from the second device within a predefined time after the transmission of the first frame.

6. The method of claim 5 , further comprising:

discarding the unusable estimated channel response.

7. A first device capable of full duplex radio communications, the first device comprising:

a transmitter configured to transmit a first frame to a second device;

a self interference cancellation (SIC) controller coupled to the transmitter, wherein the SIC controller is configured to:

estimate a channel response of SIC, based, at least in part, on the first frame, and

determine whether the estimated channel response is usable, based on a determination whether a second frame is received from the second device in response to the transmission of the first frame; and

an SIC executor configured to, responsive to the SIC controller having determined that the estimated channel response is usable, perform an SIC to a signal to be received after the second frame, based, at least in part, on the usable estimated channel response, wherein the SIC executor is configured to perform the SIC by:

estimation of a self interference, based, at least in part, on the usable estimated channel response; and

subtraction of the estimated self interference from the signal.

8. The first device of claim 7 , further comprising:

a receiver coupled to the SIC controller and configured to receive the second frame from the second device within a predefined time after the transmitter transmitted the first frame,

wherein the SIC controller is configured to determine that the estimated channel response is usable based on the reception of the second frame.

9. The first device of claim 8 , wherein the SIC controller is further configured to update the channel response of the SIC with the usable estimated channel response.

10. The first device of claim 8 , wherein

the SIC executor is coupled to the receiver.

11. The first device of claim 8 , wherein the first frame includes at least one of a data frame or a probe request frame, and

wherein the second frame includes at least one of an acknowledge (ACK) frame or a probe response frame.

12. The first device of claim 7 , wherein the SIC controller is configured to determine that the estimated channel response is unusable, when no frame is received by the first device from the second device within a predefined time after the transmitter transmitted the first frame.

13. The first device of claim 12 , wherein the SIC controller is further configured to discard the unusable estimated channel response.

14. A non-transitory computer-readable storage medium having stored thereon computer-executable instructions that, in response to execution by a processor associated with a first device capable of full duplex radio communications cause the first device to perform operations, comprising:

transmitting a first frame to a second device;

estimating a channel response of self interference cancellation (SIC), based, at least in part, on the first frame;

identifying a second frame received from the second device within an amount of time after the transmission of the first frame;

determining that the estimated channel response is usable; and

estimating a self interference based, at least in part, on the usable estimated channel response; and

subtracting the estimated self interference from a signal to be received after the reception of the second frame.