Transceiver architecture and method for wireless base-stations

• US 7,962,174 B2
• Filed: 07/12/2006
• Issued: 06/14/2011
• Est. Priority Date: 07/12/2006
• Status: Expired due to Fees

• Current Assignee: Andrew LLC (CommScope Holding Company, Inc.)
• Original Assignee: Andrew LLC (CommScope Holding Company, Inc.)
• Inventors: Chandrasekaran, Rajiv, Lipowski, Joseph T.
• Primary Examiner(s): Pan; Yuwen
• Assistant Examiner(s): AYOTUNDE, AYODEJI O
• Application Number:
  US11/456,948
• Publication Number:
  US 20080014866A1
• Time in Patent Office: 1,798 Days
• Field of Search: 348/678, 375/296
• US Class Current: 455/561
• CPC Class Codes: H03F 1/3247 using feedback acting on predistortion circuits H03F1/3264 takes precedence
• CPC Class Codes: H03F 2200/411 the output amplifying stage of an amplifier comprising two power stages
• CPC Class Codes: H03F 3/24 of transmitter output stages
• CPC Class Codes: H04W 88/08 Access point devices
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A system for wireless communications includes a tower structure supporting at least one transmit antenna at an elevated position on the tower structure and base electronics positioned proximate a base of the tower structure. The base electronics are coupled with the transmit antenna and include an initial stage amplifier for amplifying an input signal to provide a low power transmission signal that is provided to the transmit antenna at the elevated position. A final stage amplifier is positioned proximate the transmit antenna. The final stage amplifier is a high efficiency amplifier for efficiently amplifying the low power transmission signal from the base electronics to provide a high power transmission signal to be transmitted from the transmit antenna.

Claims

1. A system for wireless communications comprising:

a tower structure supporting at least one transmit antenna at an elevated position on the tower structure;

base electronics positioned proximate a base of the tower structure and coupled with the transmit antenna, the base electronics including an initial stage amplifier for initially amplifying an input signal proximate the base of the tower to provide a low power transmission signal that is then provided to the transmit antenna at the elevated position;

a final stage amplifier positioned away from the base electronics and at the elevated position with the transmit antenna, the final stage amplifier being a high efficiency amplifier for efficiently amplifying the low power transmission signal from the base electronics to provide a high power transmission signal to be transmitted from the transmit antenna;

the base electronics further including a predistortion circuit positioned proximate the base of the tower for predistorting the input signal to the initial stage amplifier;

a predistortion receiver positioned proximate the final stage amplifier at the elevated position and coupled with the predistortion circuit, the predistortion receiver configured to receive a representative sample of the high power transmission signal for use by the predistortion circuit.

2. The system of claim 1 wherein the initial stage amplifier provides a greater percentage of the amplification of the input signal than the final stage amplifier.

3. The system of claim 2 wherein the initial stage amplifier provides in the range of 25-40 dB of gain.

4. The system of claim 2 wherein the final stage amplifier provides in the range of 10-15 dB of gain.

5. The system of claim 1 wherein the final stage amplifier has an efficiency greater than 30%.

6. The system of claim 1 wherein the final stage amplifier is a high efficiency Doherty amplifier arrangement.

7. The system of claim 1 wherein the base electronics further include a frequency source for generating at least one LO frequency, the LO frequency combined with the low power transmission signal and directed to the predistortion receiver at the elevated position.

8. A system for wireless communications comprising:

at least one transmit antenna positioned at a first remote location;

transceiver circuitry positioned at a second base location spaced from the remote location and operable for providing a low power transmission signal that is provided to the remote location;

an amplifier positioned proximate the transmit antenna at the remote location for amplifying the low power transmission signal to provide a high power transmission signal at the remote location to be transmitted from the transmit antenna;

a predistortion circuit at the base location, the predistortion circuitry configured for predistorting the transmission signal provided to the remote location;

a predistortion receiver positioned proximate the amplifier at the remote location and coupled with the predistortion circuit at the base location, the predistortion receiver configured to receive a sample of the high power transmission signal at the remote location and process the high power transmission signal for provision of a representative sample of the high power transmission signal to the predistortion circuit at the base location.

9. The system of claim 8 wherein the remote location is an elevated position on a support structure and the base location is at a base of the support structure.

10. The system of claim 8 further including a frequency source at the base location for generating at least one LO frequency, the LO frequency combined with the low power transmission signal and directed to the predistortion receiver at the remote location.

11. The system of claim 10 wherein the predistortion receiver processes the transmission signal by combining the sample of the high power transmission signal and the LO frequency to form an IF signal that is used by the predistortion circuit.

12. The system of claim 8 further including:

at least one receive antenna at the remote location to capture a receive signal;

a frequency source at the base location for generating at least one LO frequency, the LO frequency combined with the low power transmission signal and directed to the remote location;

a filter at the remote location to separate the LO frequency and the low power transmission signal.

13. The system of claim 12 including a plurality of receive antennas at the remote location and wherein the frequency source at the base location is operable for generating a plurality of LO frequencies for combining with a plurality of receive signals at the remote location to form a plurality of IF signals.

14. The system of claim 13 wherein the plurality of IF signals have different IF frequencies and further including a combiner circuit at the remote location to combine the different IF frequencies for transmission to the base location.

15. The system of claim 13 wherein the plurality of IF signals have the same IF frequency and further including plurality of receive cables for transmission of the IF signals to the base location.

16. The system of claim 11 wherein the IF signal has a frequency sufficiently separated from the frequency of the high power transmission signal in order to reduce interference.

17. The system of claim 8 further comprising a signal source at the base location for generating a signal for use by the predistortion receiver, the signal being combined with the low power transmission signal and directed to the remote location.

18. The system of claim 17, the predistortion receiver configured for using the signal to frequency convert the sample of the high power transmission signal to form a frequency converted signal that is used by the predistortion circuit for the purposes of predistorting the transmission signal.

19. The system of claim 18 wherein the signal is separated from the low power transmission signal at the remote location and used to provide an LO signal to frequency conversion circuitry to form the frequency converted signal.

20. A method for providing wireless communications comprising:

positioning at least one transmit antenna at a first remote location;

forwarding a low power transmission signal from a base location to the transmit antenna at the remote location;

amplifying, at the remote location, the low power transmission signal with an amplifier, the amplifier being a high efficiency amplifier for efficiently amplifying the low power transmission signal to provide a high power transmission signal to be transmitted from the transmit antenna;

predistorting the transmission signal with a predistortion circuit at the base location before it is forwarded to the remote location;

at the remote location, coupling off a sample of the high power transmission signal and processing the high power transmission signal and providing a representative sample of the high power transmission signal back to the predistortion circuit at the base location.

21. The method of claim 20 further comprising generating a signal for use by the predistortion receiver, the signal being combined with the low power transmission signal and directed to the remote location.

22. The method of claim 21 further comprising using the signal to frequency convert the sample of the high power transmission signal to form a frequency converted signal that is used by the predistortion circuit for the purposes of predistorting the transmission signal.

23. The method of claim 22 wherein the signal is separated from the low power transmission signal at the remote location and used to provide an LO signal to frequency conversion circuitry to form the frequency converted signal.

24. The method of claim 20 further comprising generating at least one LO frequency at the base location and combining the LO frequency with the low power transmission signal and forwarding the combined signal to the remote location.

25. The method of claim 24 further comprising processing the high power transmission signal by combining the sample of the high power transmission signal with an LO frequency to form an IF signal that is used by the predistortion circuit.

26. The method of claim 24 further comprising generating the LO frequency at the base location, combining the LO frequency with the low power transmission signal for forwarding the combined signal to the remote location and filtering the combined signal at the remote location to separate the LO frequency and the low power transmission signal.

27. The method of claim 24 further comprising positioning at least one receive antenna at the remote location to capture a receive signal, and combining the LO frequency with the receive signal at the base location to form an IF signal.

28. The method of claim 27 further comprising positioning a plurality of receive antennas and generating a plurality of LO frequencies for combining with a plurality of receive signals to form a plurality of IF signals.

29. The method of claim 28 wherein the plurality of IF signals have different IF frequencies and further including combining the different IF frequencies for transmission to the base location.

30. The method of claim 28 wherein the plurality of IF signals have the same IF frequency and further including using a plurality of receive cables to transmit the IF signals to the base location.

31. The method of claim 27 wherein the IF signal has a frequency sufficiently separated from the frequency of the high power transmission signal in order to reduce interference.