Communication relay apparatus, system, interference suppression method and program

Patent metadata

Field	Value
Publication number	US-11973573-B2
Application number	US-202218261729-A
Country	US
Kind code	B2
Filing date	Jan 12, 2022
Priority date	Jan 18, 2021
Publication date	Apr 30, 2024
Grant date	Apr 30, 2024

Abstract

It is prevented of degradation of communication quality caused by estimation errors of plural path differences between plural antennas for feeder link (FL antennas) incorporated in an aerial-staying type communication relay apparatus and plural gateway (GW) stations. The aerial-staying type communication relay apparatus estimates plural first path differences Δd ji respectively between the plural GW stations and the plural FL antennas with reference to a main path, based on plural pilot reception signals received from the plural GW stations, obtains plural correction values corresponding to the plural first path differences, based on the plural pilot reception signals, estimates a propagation path response in the transmission signal band of the feeder link, based on plural corrected second path differences Δ dji_new obtained by respectively correcting the plural first path differences with plural correction values, calculates and stores reception weights for suppressing interference signals, and applies the plural reception weights to reception signals received via the plural antennas for feeder link, with respect to each of the plural gateway stations.

First claim

The invention claimed is:

1. An aerial-staying type communication relay apparatus including a repeater-type relay communication station for relaying radio communication of a terminal apparatus and plural antennas for feeder link, comprising:
a feeder-link communication section for transmitting and receiving relay signals different from each other on a same frequency in a feeder link to and from plural gateway stations that are time-synchronized with each other, via plural antennas for feeder link; and
an interference suppression section for suppressing an interference between plural feeder links formed with the plural gateway stations,
wherein the interference suppression section comprises:
means for retrieving plural pilot reception signals corresponding to plural pilot signals transmitted respectively from the plural gateway stations in a frequency band adjacently outside a transmission signal band of the feeder link, from reception signals received via the plural antennas for feeder link;
means for estimating plural first path differences respectively between the plural gateway stations and the plural antennas for feeder link with reference to a main path, based on the plural pilot reception signals;
means for obtaining plural correction values respectively corresponding to the plural first path differences, based on the plural pilot reception signals;
means for estimating a propagation path response in the transmission signal band of the feeder link, based on plural corrected second path differences obtained by respectively correcting the plural first path differences with the plural correction values;
means for calculating and storing plural reception weights based on an estimation result of the propagation path response, with respect to each of the plural gateway stations; and
means for applying the plural reception weights to reception signals received via the plural antennas for feeder link, with respect to each of the plural gateway stations.

2. The communication relay apparatus according to claim 1 , the interference suppression section, with respect to each of the plural gateway stations, calculates and stores plural reception weights and plural transmission weights based on the estimation result of the propagation path response, applies the plural reception weights to reception signals received via the plural antennas for feeder link, and applies the plural transmission weights to transmission signals to be transmitted via the plural antennas for feeder link.

3. An aerial-staying type communication relay apparatus including a repeater-type relay communication station for relaying radio communication of a terminal apparatus and plural antennas for feeder link, comprising:
a feeder-link communication section for transmitting and receiving relay signals different from each other on a same frequency in a feeder link to and from plural gateway stations that are time-synchronized with each other, via plural antennas for feeder link; and
an interference suppression section for suppressing an interference between plural feeder links formed with the plural gateway stations,
wherein the interference suppression section comprises:
means for retrieving plural pilot reception signals corresponding to plural pilot signals transmitted respectively from the plural gateway stations in a frequency band adjacently outside a transmission signal band of the feeder link, from reception signals received via the plural antennas for feeder link;
means for estimating plural first path differences respectively between the plural gateway stations and the plural antennas for feeder link with reference to a main path, based on the plural pilot reception signals;
means for obtaining plural correction values respectively corresponding to the plural first path differences, based on the plural pilot reception signals;
means for estimating a propagation path response in the transmission signal band of the feeder link based on plural corrected second path differences obtained by respectively correcting the plural first path differences with the plural correction values;
means for calculating and storing plural transmission weights based on an estimation result of the propagation path response, with respect to each of the plural gateway stations; and
means for applying the plural transmission weights to transmission signals to be transmitted via the plural antennas for feeder link, with respect to ach of the plural gateway stations.

4. The communication relay apparatus according to claim 1 ,
wherein the communication relay apparatus, with respect to each of the plural first path differences, obtains a difference between two pilot reception signals respectively corresponding to the main path and the other path of the first path difference, while changing a phase difference of one of the two pilot reception signals relative to the other pilot reception signal, and obtains a correction value corresponding to the first path difference based on the phase difference when the difference between the two pilot reception signals is minimized.

5. The communication relay apparatus according to claim 4 ,
wherein the communication relay apparatus adjusts an amplitude of at least one of the two pilot reception signals so that amplitudes of the two pilot reception signals become a same value as each other.

6. The communication relay apparatus according to claim 5 ,
when a frequency of the pilot reception signal is f [Hz], a wavelength of the pilot reception signal is λ [m], and the first path difference is Δd [m], a ratio of absolute values of the amplitudes of the two pilot reception signals is y, a correction angle of the phase difference to be changed is ε [degrees], and light velocity is c [m/s],
wherein the communication relay apparatus obtains a value of error function E(ε) by adding the one pilot reception signal and the signal obtained by correcting the other pilot reception signal as shown in the following equation (1), and obtains the correction value corresponding to the first path difference based on the correction angle E of the phase difference when the value of the error function E(ε) is minimized

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γ
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π

×

e

j
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2
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π
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f
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Δ
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d

c

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λ

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Assignees

• Softbank Corp

Inventors

• Fujii Takafumi
• Fujii Teruya

Classifications

• H04B7/18513 Primary

  Transmission in a satellite or space-based system · CPC title

• H04J11/0036 Primary

  at the receiver · CPC title

• H04B7/18504

  Aircraft used as relay or high altitude atmospheric platform · CPC title