Adaptive power amplifier linearization in time division duplex communication systems

1. In a transceiver, a method for adaptive power amplifier linearization in time division duplex communication systems, comprising:

in response to a first condition:

using a feedback signal generated by receiving subsystem circuitry, to perform adaptive power amplifier linearization on a signal to be transmitted,

where using the feedback signal comprises comparing the feedback signal to a modulated data signal and updating characteristics of an adaptive predistortion algorithm based on the comparison; and

in response to a second condition:

performing operations in order to determine receive data from a received radio frequency (RF) signal, the operations using at least the receiving subsystem circuitry.

2. The method of claim 1 , wherein the first and second conditions are mutually exclusive.

3. The method of claim 1 , wherein:

in response to the first condition, decoupling the received RF signal from the receiving subsystem circuitry so that receive data cannot be determined from the received RF signal; and

in response to the second condition, not performing adaptive power amplifier linearization.

4. The method of claim 1 , wherein:

the signal to be transmitted is received from a first input of the transceiver;

performing adaptive power amplifier linearization on the signal to be transmitted results in an amplified transmit RF signal;

in response to the first condition:

coupling the amplified transmit RF signal to a receiving subsystem;

converting, using the receiving subsystem circuitry, the amplified transmit RF signal to the feedback signal;

coupling the feedback signal to adaptive power amplifier linearization circuitry, the adaptive power amplifier linearization circuitry performing the adaptive power amplifier linearization; and

outputting the amplified transmit RF signal to a first output of the transceiver; and

in response to the second condition:

receiving the received RF signal from a second input of the transceiver;

coupling the received RF signal to the receiving subsystem circuitry;

converting, using the receiving subsystem circuitry, the received RF signal to a received signal suitable for use in determining the receive data; and

coupling the received signal to a second output of the transceiver.

5. The method of claim 1 , wherein the transceiver comprises:

a transmission portion that performs the adaptive power amplifier linearization on the signal to be transmitted; and

a reception portion that performs the operations in order to determine receive data from the received RF signal and that comprises the receiving subsystem circuitry.

6. The method of claim 5 , wherein the first condition comprises the transmission portion being in a first state, and wherein the second condition comprises the transmission portion being in a second state.

7. The method of claim 5 , wherein the first condition comprises the transmission portion transmitting data, and wherein the second condition comprises the transmission portion not transmitting data.

8. A method for adaptive power amplifier linearization in time division duplex communication systems, comprising:

in response to a first condition:

using a feedback signal generated by receiving subsystem circuitry, to perform adaptive power amplifier linearization on a signal to be transmitted;

in response to a second condition:

performing operations in order to determine receive data from a received radio frequency (RF) signal, the operations using at least the receiving subsystem circuitry,

wherein the transceiver comprises a transmission portion that performs the adaptive power amplifier linearization on the signal to be transmitted;

a reception portion that performs the operations in order to determine receive data from the received RF signal and that comprises the receiving subsystem circuitry;

the method further comprising:

determining a number of times the transmission portion has transmitted data since a predetermined point; and

determining if the number of times the transmission portion has transmitted data is a predetermined number of times,

wherein the first condition comprises the transmitter transmitting data for the predetermined number of times and the second condition comprises the transmitter not transmitting data.

9. The method of claim 5 , wherein the first condition comprises the receiving portion being in a first state and wherein the second condition comprises the receiving portion being in a second state.

10. The method of claim 1 , wherein the first condition comprises a first time period scheduled for performing adaptive power amplifier linearization, and wherein the second condition comprises a second time period scheduled for performing operations in order to determine receive data from the received RF signal.

11. The method of claim 10 , wherein the method further comprises transmitting data, and wherein performing adaptive power amplifier linearization is performed when transmitting data.

12. A transceiver comprising:

first and second inputs;

first and second outputs;

adaptive power amplifier linearization circuitry comprising first and second inputs and an output, the first input of the adaptive power amplifier linearization circuitry coupled to the first input of the transceiver, the output of the adaptive power amplifier linearization circuitry coupled to the first output of the transceiver;

a first switch comprising first and second input terminals and an output terminal, the first input terminal of the first switch coupled to the output of the adaptive power amplifier linearization circuitry, the second input terminal of the first switch coupled to the second input of the transceiver;

receiving subsystem circuitry having an input and an output, the input of the receiving subsystem circuitry coupled to the output terminal of the first switch; and

a second switch comprising first and second output terminals and an input terminal, the input terminal of the second switch coupled to the output of the receiving subsystem circuitry, the first output terminal of the second switch coupled to the second input of the adaptive power amplifier predistortion algorithm circuitry, and the second output terminal of the second switch coupled to the second output of the transceiver.

13. The transceiver of claim 12 , wherein:

the receiving subsystem circuitry is adapted to convert a signal provided by the output terminal of the first switch into a first signal suitable for coupling to the second input of the adaptive power amplifier linearization circuitry and for use in determining receive data; and

the adaptive power amplifier linearization circuitry is adapted to distort, by using at least the first signal, a second signal from the first input and adapted to amplify the second signal, wherein the distortion and amplification create a third signal on the output of the adaptive power amplifier linearization circuitry and create an approximately linear relationship between the second and third signals.

14. The transceiver of claim 13 , wherein the adaptive power amplifier linearization circuitry further comprises:

adaptive predistortion algorithm circuitry comprising two inputs and an output, the first input of the adaptive predistortion algorithm circuitry coupled to the first input of the adaptive power amplifier linearization circuitry, the second input of the adaptive predistortion algorithm circuitry coupled to the second input of the adaptive power amplifier linearization circuitry, the adaptive predistortion algorithm circuitry adapted to distort, by using at least the first signal, the second signal to create a fourth signal on the output of the adaptive predistortion algorithm circuitry; and

a power amplifier comprising an input and an output, the input of the power amplifier coupled to the output of the adaptive predistortion algorithm circuitry, the output of the power amplifier coupled to the output of the adaptive power amplifier linearization circuitry, the power amplifier adapted to amplify the fourth signal and adapted to produce the third signal.

15. The transceiver of claim 12 , wherein:

the first switch couples the first input terminal of the first switch to the output terminal of the first switch in a first position and couples the second input terminal of the first switch to the first output terminal of the first switch in a second position; and

the second switch couples the input terminal of the second switch to the first output terminal of the second switch in the first position and couples the input terminal of the second switch to the second output terminal of the second switch in the second position.

16. The transceiver of claim 15 , further comprising control circuitry coupled to the first and second switches, the control circuitry adapted to switch both the first and second switches between the first and second positions.

17. The transceiver of claim 16 , wherein the control circuitry is further adapted to switch both the first and second switches into the first position for a first time period and to switch both the first and second switches into the second position for a second time period.

18. The transceiver of claim 16 , wherein:

the control circuitry is further adapted to switch both the first and second switches from the second position to the first position based on a first state of transmission, and is further adapted to switch both the first and second switches from the first position to the second position based on a second state of transmission.

19. The transceiver of claim 16 , wherein:

the first state of transmission corresponds to transmitting data; and

the second state of transmission corresponds to receiving data and not transmitting data.

20. The transceiver of claim 12 , further comprising:

a modulator intermediate and coupled to the first input and the input of the adaptive power amplifier linearization circuitry;

a low noise amplifier intermediate and coupled to the second input and the second input terminal of the first switch; and

a demodulator intermediate and coupled to the second output terminal of the second switch and the second output.