Apparatus and methods for synchronization of transmitters

1. A first-transceiver system for use in an antenna diversity scheme, the first-transceiver system comprising:

a first-time/clock-generation-unit;

a first-receiver, configured to receive a wireless first-common-signal from a third-party-transmitter, wherein the first-common-signal is representative of a common-signal transmitted by the third-party-transmitter;

a first-transmitter; and

a timing-controller, configured to:

receive signalling representative of the first-common-signal;

receive signalling representative of a wireless second-common-signal as received at a second-transceiver, the second-transceiver comprising a second-time/clock-generation-unit, the wireless second-common-signal being representative of the common-signal;

generate a timing-signal based on the first-common-signal and the second-common-signal,

wherein:

the first-transceiver system is configured to set the first-time/clock-generation-unit, based on the timing-signal, to reduce an alignment-error between the first-time/clock-generation-unit and the second-time/clock-generation-unit;

the first-transmitter is configured to transmit a wireless first-transmission-signal, in accordance with the first-time/clock-generation-unit, as part of the antenna diversity scheme, wherein:

the first-transmission-signal corresponds to a second-transmission-signal that is transmitted by the second-transceiver; and

the antenna diversity scheme comprises aligned transmission of both the first-transmission-signal and the second-transmission-signal.

2. The first-transceiver system of claim 1 , wherein the first transceiver system is configured to set the first-time/clock-generation-unit by adjusting a time of the first-time/clock-generation-unit and/or a frequency of the first-time/clock-generation-unit.

3. The first transceiver system of claim 2 , wherein the first-time/clock-generation-unit comprises a frequency synthesizer and a system timer, and wherein the first-transceiver is configured to set the first-time/clock-generation-unit by one or more of:

applying an offset to a count of the system timer;

applying a frequency offset to one or more of:

a carrier frequency that is provided to tuners of the transmitter and/or the receiver,

a sampling frequency that is provided to a DAC of the transmitter and/or an ADC of the receiver,

a system timer frequency that is provided to the system timer;

tuning a crystal oscillator that is associated with the frequency synthesizer;

changing divider settings of a phase locked loop that is associated with the frequency synthesizer;

digitally rotating digital samples for compensating an RF carrier frequency offset; and

resampling of a digital signal for compensating a difference in DA converter frequency.

4. The first-transceiver system of claim 1 , wherein the common-signal comprises a predetermined pattern of information, and the timing-controller is configured to generate the timing-signal based on a correlation technique.

5. The first-transceiver system of claim 1 , wherein the timing-controller is configured to generate the timing-signal based on a comparison of first-IQ-samples representative of the first-common-signal and second-IQ-samples representative of the second-common-signal.

6. The first-transceiver system of claim 1 , wherein the aligned transmission comprises transmission of both the first-transmission-signal and the second-transmission-signal aligned with respect to time and/or frequency such that they constructively combine when received at a remote receiver.

7. A multi-transceiver system comprising:

a first-transceiver comprising:

a first-time/clock-generation-unit;

a first-receiver, configured to receive a wireless first-common-signal from a third-party-transmitter, wherein the first-common-signal is representative of a common-signal transmitted by the third-party-transmitter;

a first-transmitter; and

a timing-controller, configured to:

receive signalling representative of the first-common-signal;

receive signalling representative of a wireless second-common-signal as received at a second-transceiver, the second-transceiver comprising a second-time/clock-generation-unit, the wireless second-common-signal being representative of the common-signal;

generate a timing-signal based on the first-common-signal and the second-common-signal,

wherein:

the first-transceiver system is configured to set the first-time/clock-generation-unit, based on the timing-signal, to reduce an alignment-error between the first-time/clock-generation-unit and the second-time/clock-generation-unit;

the first-transmitter is configured to transmit a wireless first-transmission-signal, in accordance with the first-time/clock-generation-unit, as part of the antenna diversity scheme, wherein:

the first-transmission-signal corresponds to a second-transmission-signal that is transmitted by the second-transceiver; and

the antenna diversity scheme comprises aligned transmission of both the first-transmission-signal and the second-transmission-signal,

the second transceiver, and

a digital communication channel configured to exchange coordination-signalling between the first-transceiver and the second-transceiver to co-ordinate setting the first-time/clock-generation-unit and/or the second time/clock-generation-unit.

8. The multi-transceiver system of claim 7 , wherein the timing-controller is:

co-located with the first-transceiver; and

connected to the second-transceiver via the digital communication channel.

9. The multi-transceiver system of claim 7 , further comprising a central control unit that is separate from the first-transceiver, wherein the central control unit:

is configured to provide the functionality of the timing-controller; and

is connected to the first-transceiver and the second-transceiver via the digital communication channel.

10. The multi-transceiver system of claim 7 , wherein the timing-controller is configured to set the first-time/clock-generation-unit and the second-time/clock-generation-unit based on an average time and/or frequency derived from the first-common-signal and the second-common-signal.

11. The first-transceiver system of claim 1 , wherein:

the first-receiver is configured to receive a wireless second-alignment-signal from the second-transceiver, wherein the wireless second-alignment-signal is representative of a state of the second-time/clock-generation-unit;

the first transceiver system is configured to set the first-time/clock-generation-unit, based on the wireless second-alignment-signal, to reduce an alignment-error between the first-time/clock-generation-unit and the second-time/clock-generation-unit.

12. The first transceiver system of claim 11 , wherein the wireless second-alignment-signal comprises a prefix and/or a postfix portion of an earlier-second-transmission-signal, and wherein the earlier-second-transmission-signal is transmitted before the second-transmission-signal.

13. The first transceiver system of claim 11 , further configured to:

receive a plurality of wireless alignment-signals, including the wireless second-alignment-signal, from a plurality of other transceivers, including the second-transceiver; and

set the first-time/clock-generation-unit, based on the plurality of wireless alignment-signals, to reduce alignment-errors between the first-time/clock-generation-unit and a plurality of time/clock-generation-units of the other transceivers.

14. The first transceiver system of claim 11 , wherein the coordination-signalling comprises one or more of:

a time-of-transmission of the second-alignment-signal;

a value of the second-time/clock-generation-unit at a predefined moment in time relative to the time-of-transmission of the second-alignment-signal;

a value of the second-time/clock-generation-unit at a time-of-transmission of the second-alignment-signal;

a delay between the time-of-transmission and the time-of-reception of the second-alignment-signal;

an expected time of arrival of the wireless second-alignment-signal at the first-transceiver; and/or

an expected time of arrival of the wireless first-alignment-signal at the second-transceiver.

15. A method of operating a first-transceiver system for use in an antenna diversity scheme, the first-transceiver system comprising a first-time/clock-generation-unit, the method comprising:

receiving at the first-transceiver system a wireless first-common-signal from a third-party-transmitter, wherein the first-common-signal is representative of a common-signal transmitted by the third-party-transmitter;

receiving signalling representative of a wireless second-common-signal as received at a second-transceiver, the second-transceiver comprising a second-time/clock-generation-unit, the wireless second-common-signal being representative of the common-signal;

generating a timing-signal based on the first-common-signal and the second-common-signal,

setting the first-time/clock-generation-unit, based on the timing-signal, to reduce an alignment-error between the first-time/clock-generation-unit and the second-time/clock-generation-unit;

transmitting a wireless first-transmission-signal, in accordance with the first-time/clock-generation-unit, as part of the antenna diversity scheme, wherein:

the first-transmission-signal corresponds to a second-transmission-signal that is transmitted by the second-transceiver; and

the antenna diversity scheme comprises aligned transmission of both the first-transmission-signal and the second-transmission-signal.

16. The method of claim 15 , wherein setting the first-time/clock-generation-unit further comprises adjusting a time of the first-time/clock-generation-unit and/or a frequency of the first-time/clock-generation-unit.

17. The method of claim 16 , wherein setting the first-time/clock-generation-unit further comprises applying an offset to a count of the system timer.

18. The method of claim 15 , further comprising generating, by way of a timing-controller, the timing-signal based on a correlation technique.

19. The method of claim 18 , further comprising generating, by way of the timing-controller, the timing-signal based on a comparison of first-IQ-samples representative of the first-common-signal and second-IQ-samples representative of the second-common-signal.

20. The method of claim 15 , further comprising transmitting both the first-transmission-signal and the second-transmission-signal aligned with respect to time and/or frequency such that they constructively combine when received at a remote receiver.