Wireless devices and systems including examples of mismatch correction scheme

1. An apparatus comprising:

a transmitter configured to transmit communications signaling via a first antenna, the transmitter comprising a filter configured for digital mismatch correction;

a receiver configured to receive communications signaling via a second antenna; and

a switch configured to selectively activate a first switch path to couple the transmitter and the first antenna and a second switch path to couple the receiver and the transmitter to provide communications signaling received via the transmitter as feedback for the filter through the receiver, wherein the switch is further configured to receive a selection signal indicating whether the second switch path is to be activated, and the selection signal is based partly on a downlink subframe or an uplink subframe.

2. The apparatus of claim 1 , further comprising:

a weight estimation circuit coupled between the transmitter and receiver.

3. The apparatus of claim 2 , wherein the weight estimation circuit is configured to:

determine coefficient data based on the feedback received via the second switch path;

modify the communications signaling responsive to the determined weight coefficient data; and

provide the modified communication signaling to the first antenna.

4. The apparatus of claim 1 , wherein the first switch path is further configured to provide the communications signaling based at least in part on the feedback received via the second switch path.

5. The apparatus of claim 1 , wherein the filter is configured to at least partially compensate for digital mismatch in the communications signaling to be transmitted via the first antenna based on the feedback received through the receiver.

6. The apparatus of claim 1 , wherein the receiver is configured to be coupled to the transmitter via the switch to provide the feedback to the filter to at least partially compensate for digital mismatch in the communications signaling to be transmitted via the first antenna.

7. The apparatus of claim 1 , wherein the transmitter further comprises an other filter configured for power amplifier noise correction.

8. The apparatus of claim 7 , wherein an output of the other filter configured for power amplifier noise correction is coupled to an input of the filter configured for digital mismatch correction.

9. The apparatus of claim 7 , wherein an input of the other filter configured for power amplifier noise correction is coupled to an output of the filter configured for digital mismatch correction.

10. The apparatus of claim 1 , wherein the switch is further configured to provide, in a first switch state, the communications signaling received via the transmitter to the first antenna in the activated first switch path, and to provide, in a second switch state, the communications signaling received via the second antenna to the receiver in the activated second switch path.

11. The apparatus of claim 1 , wherein the transmitter is coupled, via the switch in a first switch state, to the first antenna to provide the communications signaling to the first antenna.

12. The apparatus of claim 11 , wherein the transmitter is further configured to provide the communications signaling to be transmitted via the first antenna after digital mismatch in the communications signaling to be transmitted via the first antenna is compensated.

13. The apparatus of claim 12 , wherein the digital mismatch in the communications signaling is compensated based on the feedback.

14. A method comprising:

transmitting a communications signal via a first radio frequency (RF) chain during a downlink subframe of a radio frame in a system configured for time-division duplexing (TDD) communication;

providing the communications signal from the first RF chain to a low-noise amplifier (LNA) of a second RF chain during the downlink subframe;

converting an analog signal that is based at least in part on an output of the LNA to a digital signal within the second RF chain; and

providing a feedback signal from the second RF chain to a filter of the first RF chain during the downlink subframe, wherein the feedback signal is based at least in part on the digital signal converted within the second RF chain and the filter is configured for digital mismatch correction.

15. The method of claim 14 , further comprising:

receiving another communications signal at the LNA of the second RF chain during an uplink subframe of the radio frame;

converting an other analog signal that is based at least on part on the other communications signal to an other digital signal within the second RF chain; and

providing an other feedback signal from the second RF chain at the filter of the first RF chain during the uplink subframe, wherein the other feedback signal is based at least in part on the other digital signal.

16. The method of claim 14 , further comprising:

determining, by a weight estimation circuit in the first RF chain, coefficient data based on the feedback signal received from the second RF chain; and

modifying, by the weight estimation circuit, the communications signal responsive to the determined coefficient data.

17. The method of claim 14 , wherein the communications signal is transmitted via the filter in the first RF chain, responsive to the feedback signal provided to the filter.

18. The method of claim 14 , wherein the communications signal is provided from the first RF chain to the LNA of the second RF chain via a switch in the first RF chain, and

wherein the switch is in a first switch state during the downlink subframe to at least partially compensate for digital mismatch in the communications signal.

19. The method of claim 14 , wherein the communications signal is transmitted via a filter configured for nonlinear power amplifier noise compensation, and

wherein an output of the filter configured for nonlinear power amplifier noise compensation is coupled to an input of the filter configured for digital mismatch correction.

20. The method of claim 14 , further comprising receiving, by a switch in the first RF chain, a selection signal indicating whether the first RF chain is to be activated, the selection signal based partly on the downlink subframe.

21. The method of claim 14 , further comprising:

providing, by a switch in the first RF chain, the communications signal to the LNA of the second RF chain based at least in part on the switch in a first switch state; and

transmitting, by the switch in the first RF chain, the communications signal based at least in part on the switch in a second switch state.

22. An apparatus comprising:

a transmit antenna configured to transmit a signal on a sideband link to a peer device, wherein the transmit signal is based at least in part on feedback provided by a feedback circuit; and

a receive antenna configured to receive an other signal on the sideband link from the peer device and to provide the other signal to a receive circuit and the feedback circuit, wherein the feedback circuit and the receive circuit comprise components of a same radio frequency (RF) chain, wherein the RF chain comprises an intermediate frequency (IF) filter, an analog-to-digital converter, and a numerically controlled oscillator (NCO), and wherein the NCO is coupled to a filter configured for digital mismatch correction.

23. The apparatus of claim 22 , wherein the transmit signal is provided to the transmit antenna via the filter configured for digital mismatch correction, and

wherein the transmit signal is provided to the transmit antenna via the filter based on the feedback.

24. The apparatus of claim 22 , wherein the transmit signal is provided to the transmit antenna via the filter configured for digital mismatch correction in a transmit circuit, and

wherein the filter is coupled to a coefficient calculator configured to:

receive the feedback from the feedback circuit,

determine coefficient data used to reduce error introduced into the transmit signal by digital mismatch, and

modify the transmit signal responsive to the determined coefficient data.