Remote radio head unit system with wideband power amplifier

• US 9,814,053 B2
• Filed: 06/30/2015
• Issued: 11/07/2017
• Est. Priority Date: 12/21/2009
• Status: Active Grant

• Current Assignee: Dali Systems Co., Ltd.
• Original Assignee: Dali Systems Co., Ltd.
• Inventors: Wang, Chengxun, Stapleton, Shawn Patrick
• Primary Examiner(s): Harper, Kevin C
• Application Number:
  US14/754,908
• Publication Number:
  US 20150382363A1
• Time in Patent Office: 861 Days
• CPC Class Codes: H03F 1/0277 Selecting one or more amplifiers from a plurality of amplifiers
• CPC Class Codes: H03F 2200/111 the amplifier being a dual or triple band amplifier, e.g. 900 and 1800 MHz, e.g. switched or not switched, simultaneously or not
• CPC Class Codes: H03F 2200/294 the amplifier being a low noise amplifier [LNA]
• CPC Class Codes: H03F 2200/321 Use of a microprocessor in an amplifier circuit or its control circuit
• CPC Class Codes: H03F 2203/7209 the gated amplifier being switched from a first band to a second band
• CPC Class Codes: H03F 3/19 with semiconductor devices only
• CPC Class Codes: H03F 3/245 with semiconductor devices only
• CPC Class Codes: H03F 3/72 Gated amplifiers, i.e. amplifiers which are rendered operative or inoperative by means of a control signal
• CPC Class Codes: H04B 1/0053 with common antenna for more than one band
• CPC Class Codes: H04B 1/0057 using diplexing or multiplexing filters for selecting the desired band
• CPC Class Codes: H04B 1/006 using switches for selecting the desired band H04B1/0057 takes precedence
• CPC Class Codes: H04B 1/0067 with one or more circuit blocks in common for different bands
• CPC Class Codes: H04B 1/10 Means associated with receiver for limiting or suppressing noise or interference
• CPC Class Codes: H04B 1/123 using adaptive balancing or compensation means adaptive filter circuits and algorithms H03H
• CPC Class Codes: H04B 1/40 Circuits
• CPC Class Codes: H04B 1/525 with means for reducing leakage of transmitter signal into the receiver

Abstract

A remote radio head unit (RRU) system for multiple operating frequency bands, multi-channels, driven by a single or more wide band power amplifiers. More specifically, the present invention enables multiple-bands RRU to use fewer power amplifiers in order to reduce size and cost of the multi-band RRU. The present invention is based on the method of using duplexers and/or interference cancellation system technique to increase the isolation between the transmitter signal and receiver signal of the RRU.

Claims

1. An interference mitigation system for improving isolation between transmitters and receivers in wireless communications systems comprising:

a power amplifier operable to receive and amplify a received signal at a predetermined frequency to provide a transmit signal;

a feedback coupler coupled to the power amplifier and operable to provide a feedback signal based on the transmit signal, wherein a characteristic of the feedback signal is representative of a characteristic of the transmit signal;

an interference cancellation unit coupled to the feedback coupler and operable to generate a processed signal;

a circulator coupled to the power amplifier;

an antenna coupled to the circulator and operable to broadcast the transmit signal at the predetermined frequency and to receive an intake signal at the predetermined frequency;

a combiner that is operable to combine the processed signal with the intake signal from the antenna to generate a combined signal; and

a low noise amplifier coupled to the combiner and operable to receive the combined signal.

2. The interference mitigation system of claim 1 further comprising a multi-band frequency filter coupled to the feedback coupler.

3. The interference mitigation system of claim 1 further comprising a second feedback coupler coupled to the combiner and operable to provide a second feedback signal to the interference cancellation unit.

4. The interference mitigation system of claim 3 wherein the interference cancellation unit is operable to process the second feedback signal in addition to the feedback signal.

5. The interference mitigation system of claim 1 further comprising a transmit switch coupled between the power amplifier and the antenna.

6. The interference mitigation system of claim 5 further comprising a receive switch coupled between the antenna and the combiner.

7. The interference mitigation system of claim 1 wherein the interference cancellation unit includes a plurality of delay blocks.

8. The interference mitigation system of claim 7 wherein each of the plurality of delay blocks is associated with a frequency band.

9. The interference mitigation system of claim 7 wherein the interference cancellation unit further includes a plurality of attenuators and a plurality of phase shifters.

19. The interference mitigation system of claim 1 wherein the antenna is operable to transmit and receive concurrently at the predetermined frequency.

10. An interference mitigation system for improving isolation between transmitters and receivers in wireless communications systems comprising:

a power amplifier operable to receive and amplify a received signal at a predetermined frequency to provide a transmit signal at the predetermined frequency;

a feedback coupler coupled to the power amplifier and operable to provide a feedback signal based on the transmit signal, wherein a characteristic of the feedback signal is representative of a characteristic of the transmit signal;

an interference cancellation unit including a plurality of delay blocks and operable to process the feedback signal to generate a processed signal;

an antenna operable to;

broadcast the transmit signal at the predetermined frequency; and

receive an intake signal at the predetermined frequency;

a combiner that is operable to combine the processed signal with the intake signal from the receiver to generate a combined signal; and

a low noise amplifier coupled to the combiner and operable to receive the combined signal.

11. The interference mitigation system of claim 10 further comprising a multi-band frequency filter coupled to the feedback coupler.

12. The interference mitigation system of claim 10 further comprising a second feedback coupler coupled to the combiner and operable to provide a second feedback signal to the interference cancellation unit.

13. The interference mitigation system of claim 12 wherein the interference cancellation unit processes the second feedback signal in addition to the feedback signal.

14. The interference mitigation system of claim 10 further comprising a transmit switch coupled between the power amplifier and the antenna.

15. The interference mitigation system of claim 14 further comprising a receive switch coupled between the antenna and the combiner.

16. The interference mitigation system of claim 10 wherein each of the plurality of delay blocks is associated with a frequency band.

17. The interference mitigation system of claim 16 wherein the interference cancellation unit further includes a plurality of attenuators and a plurality of phase shifters.

18. The interference mitigation system of claim 10 wherein the antenna is operable to transmit and receive concurrently at the predetermined frequency.