Remote radio head unit system with wideband power amplifier

• US 10,153,789 B2
• Filed: 09/28/2017
• Issued: 12/11/2018
• 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:
  US15/718,469
• Publication Number:
  US 20180152947A1
• Time in Patent Office: 439 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. A dual channel remote radio unit (RRU) comprising:

a dual band input including inputs for a first frequency band and a second frequency band;

a duplexer coupled to the dual band input and configured to output a combined signal comprising the first frequency band and the second frequency band;

a wideband power amplifier coupled to the duplexer and configured to amplify the combined signal;

a diplexer coupled to the wideband power amplifier, wherein the diplexer includes a first output for the first frequency band and a second output for the second frequency band;

a first switch and a second switch coupled to the first output and the second output of the diplexer respectively;

a first circulator and a second circulator coupled to the first switch and the second switch respectively, wherein the first circulator and the second circulator are coupled to an antenna;

a first receive path coupled to the first circulator, wherein the first receive path is associated with the first frequency band; and

a second receive path coupled to the second circulator, wherein the second receive path is associated with the second frequency band.

2. The RRU of claim 1 further comprising:

a feedback coupler coupled to the first output of the diplexer and operable to provide a feedback signal based on the first output, wherein a characteristic of the feedback signal is representative of a characteristic of the first output;

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

a combiner coupled to the first receive path, wherein the combiner is operable to combine the processed signal with a received signal.

3. The RRU of claim 2 further comprising:

a second feedback coupler coupled to the second output of the diplexer and operable to provide a second feedback signal based on the second output, wherein a second characteristic of the second feedback signal is representative of a second characteristic of the second output, wherein the interference cancellation unit is coupled to the second feedback coupler and operable to generate a second processed signal associated with the second output; and

a second combiner coupled to the second receive path, wherein the second combiner is operable to combine the processed signal with a second received signal.

4. The RRU of claim 2 further comprising a multi-band frequency filter coupled to the feedback coupler.

5. The RRU of claim 2 further comprising a second feedback coupler coupled to the combiner and operable to provide a second feedback signal to the interference cancellation unit.

6. The RRU of claim 2 wherein the interference cancellation unit includes a delay block, an attenuator, and a phase shifter.

7. The RRU of claim 1 further comprising:

a second duplexer coupled to the first circulator and the second circulator;

a first receive switch coupled to the first circulator; and

a second receive switch coupled to the second circulator.

8. The RRU of claim 1 further comprising switch-operating logic that controls a position of the first switch and a position of the second switch.

9. A method for operating a dual channel remote radio unit (RRU), the method comprising:

receiving a first signal associated with a first frequency band;

receiving a second signal associated with a second frequency band;

combining, by a duplexer, the first signal and the second signal to form a combined signal;

amplifying, by a wideband power amplifier, the combined signal;

separating the combined signal, by a diplexer, into a first amplified signal associated with the first frequency band and a second amplified signal associated with the second frequency band;

controlling, by the RRU, a first switch associated with the first amplified signal and a second switch associated with the second amplified signal, wherein the first switch, and the second switch are coupled to an antenna; and

transmitting the first amplified signal or the second amplified signal.

10. The method of claim 9 further comprising:

generating a feedback signal based on the first amplified signal, wherein a characteristic of the feedback signal is representative of a characteristic of the first amplified signal;

processing the feedback signal to generate a processed signal;

receiving an intake signal during a second time slot while a third switch is in a first position, wherein the intake signal includes a first component from a signal received by the antenna and a second component of interference from the first amplified signal or the second amplified signal, wherein whether the third switch is in the first position or a second position is based on a time-division multiplexing technique; and

combining the intake signal and the processed signal to generate a combined signal.

11. The method of claim 10 wherein processing includes shifting a phase of the feedback signal.

12. The method of claim 10 wherein processing includes adjusting a magnitude of the feedback signal based on a magnitude of another signal.

13. The method of claim 10 wherein the feedback signal and a second signal are processed using a correlation technique.

14. The method of claim 10, wherein the processing of the feedback signal includes isolating each of a plurality of frequency bands within the feedback signal.

15. The method of claim 10, further comprising generating a second feedback signal based on the second amplified signal, wherein the second feedback signal is representative of the second amplified signal, and wherein the feedback signal is processed with the second feedback signal to generate a second processed signal.