To suppress the influence of radio wave interference without increasing a delay time, by making channel changeover be unnecessary even under an environment in which spatial restriction or restriction on available frequency resources is severe.SOLUTION: A vehicle radio communication system includes a terminal that when another terminal in the system is a source of interference, transmits an instruction to suppress transmission output to suppress the interference. When the source of the interference is outside the system, transmission power of the terminal is strengthened to suppress the interference. A distance to the source of the interference is measured on the basis of a propagation delay time of a radio wave. The measured distance is compared with distance information on each terminal stored in a memory. Whether or not the source of interference is inside the system is identified on the basis of a result of determining whether or not the distances agree with each other. Or, the distance to the source of interference is compared with an in-vehicle distance threshold. In order to identify whether the source of interference is inside or outside the system, a fluctuation range of the distance to the source of interference, a fluctuation range of reception power, antenna directivity, and the like are considered. An adjustment range of the transmission power is determined depending on reception power of a detected interference wave. A signal power to interference power ratio SIR is improved by power control.SELECTED DRAWING: Figure 3
【課題】空間の制約や利用可能な周波数資源の制約が大きい環境でも、チャネル切替を不要とし、遅延時間を増加させることなく電波干渉の影響を低減すること。【解決手段】自システム内の他端末が干渉源の場合は、送信出力を抑制する指示を送り干渉を抑制する。自システム外の干渉源の場合は自端末の送信電力を増強して干渉を抑制する。電波の伝搬遅延時間に基づき干渉源までの距離を計測する。メモリが保持している各端末の距離情報と計測した距離を比較して一致するか否かで干渉源がシステム内か否かを識別する。又は干渉源の距離を車内距離閾値と比較する。干渉源がシステム内か否かを識別するために、干渉源の距離の変動幅、受信電力変動幅、アンテナ指向性などを考慮する。検出した干渉波の受信電力に応じて送信電力の調整幅を決定する。電力の制御により信号電力対干渉電力比SIRが改善される。【選択図】図3
VEHICLE RADIO COMMUNICATION SYSTEM
車両用無線通信システム
2019-01-17
Patent
Electronic Resource
Japanese
VEHICLE RADIO COMMUNICATION DEVICE AND RADIO COMMUNICATION SYSTEM
European Patent Office | 2017
|European Patent Office | 2021
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