# US 2019/0173564 A1 · Diversity receiver and terminal

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- Number: US 2019/0173564 A1
- Document ID: US20190173564A1
- Status: Published application
- Kind: A1
- Application number: 16/267,808
- Filed: 2019-02-05
- Published: 2019-06-06
- Earliest claimed: 2016-08-08
- Assignees: Huawei Technologies Co., Ltd.
- Applicants: Huawei Technologies Co., Ltd.
- Inventors: Weinan Li; Xiaoran Li; Jian Liang
- Web page: https://patentgrep.com/patent/US20190173564A1

## CPC

- H04B 7/0825: {with main and with auxiliary or diversity antennas}
- H04B 1/1036: {with automatic suppression of narrow band noise or interference, e.g. by using tuneable notch filters (H04B1/123 takes precedence; filter circuits H03H)}
- H04B 1/525: with means for reducing leakage of transmitter signal into the receiver
- H04B 7/08: at the receiving station
- H04B: TRANSMISSION

## Abstract

The present application discloses a diversity receiver and a terminal. The diversity receiver includes a first main channel and a first diversity channel, the first main channel includes an antenna diplexer and a first main transmission channel, and the first diversity channel includes a tunable bandpass filter and a first diversity receiving channel. The first diversity receiving channel is coupled to a diversity antenna by using the tunable bandpass filter, and the tunable bandpass filter is configured to: adjust a passband bandwidth of the tunable bandpass filter according to a band bandwidth of a first transmit signal generated by the first main transmission channel and a band bandwidth of a first receive signal received from the diversity antenna, and perform bandpass filtering based on the passband bandwidth on the first receive signal.

## Claims

### Claim 1

A diversity receiver, comprising:
a first main channel comprising,
an antenna diplexer, and
a first main transmission channel coupled to a main antenna by using the antenna diplexer and configured to: generate a first transmit signal according to a first baseband signal, and send the first transmit signal to the main antenna by using the antenna diplexer; and
a first diversity channel comprising,
a tunable bandpass filter, and
a first diversity receiving channel coupled to a diversity antenna by using the tunable bandpass filter and configured to: perform bandpass filtering on a first receive signal based on a tunable passband bandwidth, and generate a second baseband signal according to the filtered first receive signal.

### Claim 2 (depends on 1)

The diversity receiver according to claim 1, wherein the tunable bandpass filter is configured to adjust the passband bandwidth of the tunable bandpass filter according to a band bandwidth of the first transmit signal and a band bandwidth of a first receive signal received from the diversity antenna.

### Claim 3 (depends on 1)

The diversity receiver according to claim 1, wherein the tunable bandpass filter is configured to set the passband bandwidth of the tunable bandpass filter as a channel bandwidth of the first receive signal.

### Claim 4 (depends on 1)

The diversity receiver according to claim 1, wherein the first main channel further comprises:
a first main receiving channel configured to generate a third baseband signal according to a second receive signal received from the main antenna, wherein the third baseband signal and the second baseband signal are a pair of diversity receive signals.

### Claim 5 (depends on 4)

The diversity receiver according to claim 4, wherein each of the first main transmission channel, the first main receiving channel, and the first diversity receiving channel comprises a one of a zero intermediate frequency channel, a low intermediate frequency channel, or a superheterodyne channel.

### Claim 6 (depends on 1)

The diversity receiver according to claim 1, wherein the diversity receiver further comprises:
an adaptive filter separately coupled to the first main transmission channel and the first diversity receiving channel and configured to:
construct, by using the first baseband signal received on the first main transmission channel and by performing an adaptive filtering algorithm, a second-order intermodulation distortion (IMD2) interference signal generated because of signal leakage of the first baseband signal to the first diversity receiving channel; and
filter out the IMD2 interference signal from the second baseband signal generated by the first diversity receiving channel.

### Claim 7 (depends on 6)

The diversity receiver according to claim 6, wherein the adaptive filtering algorithm comprises at least one of a least mean square (LMS) algorithm or a recursive least square (RLS) algorithm.

### Claim 8 (depends on 6)

The diversity receiver according to claim 6, wherein the adaptive filter is configured to:
use the first baseband signal as a reference signal, synchronize the reference signal with the second baseband signal, and construct the IMD2 interference signal according to the following formula:
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IMD2 represents the constructed IMD2 interference signal, Ii represents an i-order in-phase component of the reference signal obtained after the synchronization, Qi represents an i-order quadrature component of the reference signal obtained after the synchronization, Ij represents a j-order in-phase component of the reference signal obtained after the synchronization, Qj represents a j-order quadrature component of the reference signal obtained after the synchronization, Si is an autocorrelation coefficient, Cij is a cross coefficient, nCij is a negative cross coefficient, and DC represents a direct current term, wherein i and j are natural numbers, i≤n, j≤n, and i≠j.

### Claim 9 (depends on 1)

The diversity receiver according to claim 1, comprising:
multiple main channels; and
a main switch configured to select one of the multiple main channels as the first main channel.

### Claim 10 (depends on 9)

The diversity receiver according to claim 9, comprising:
multiple diversity channels; and
a diversity switch configured to select, from the multiple diversity channels according to the first main channel determined by the main switch, one diversity channel matching the first main channel to serve as the first diversity channel, wherein a filtering range of a tunable bandpass filter in the diversity channel selected by the diversity switch does not overlap a transmit band of the first main channel, but matches a receive band of the first main channel.

### Claim 11

A terminal, comprising:
a diversity receiver, comprising:
a first main channel comprising,
an antenna diplexer; and
a first main transmission channel coupled to a main antenna by using the antenna diplexer and configured to: generate a first transmit signal according to a first baseband signal, and send the first transmit signal to the main antenna by using the antenna diplexer, and
a first diversity channel comprising,
a tunable bandpass filter; and
a first diversity receiving channel coupled to a diversity antenna by using the tunable bandpass filter and configured to: perform bandpass filtering on a first receive signal based on a tunable passband bandwidth, and generate a second baseband signal according to the filtered first receive signal; and
a processor coupled to the diversity receiver and configured to:
generate the first baseband signal, and
perform diversity receiving on the second baseband signal generated by the diversity receiver.

### Claim 12 (depends on 11)

The terminal according to claim 11, wherein the tunable bandpass filter is configured to adjust the passband bandwidth of the tunable bandpass filter according to a band bandwidth of the first transmit signal and a band bandwidth of a first receive signal received from the diversity antenna.

### Claim 13 (depends on 11)

The terminal according to claim 11, further comprising:
the main antenna and the diversity antenna, wherein the main antenna and the diversity antenna are separately coupled to the diversity receiver.