GSM-R網路隧道覆蓋同頻干擾分析

Abstract

為了對GSM-R網路隧道覆蓋進行合理的規劃，減少採用光纖直放站所帶來的同頻干擾影響，該文通過對GSM-R網路隧道覆蓋模型進行分析，提出了一種基於信號衰落分析的隧道覆蓋同頻干擾分析方法：通過比較隧道中採用全向光纖直放站情況和單向光纖直放站情況的下行信號的大尺度衰落和小尺度衰落，對這兩種情況的載波干擾比和信號傳輸時延差進行了分析，結合二者誤比特率的仿真結果，得出了其各自滿足同頻干擾要求的條件，即在採用全向光纖直放站時基站與直放站距離不宜超過1.5km，採用單向光纖直放站時基站與直放站距離可以較大，但應當小於基站的覆蓋半徑。從設備的覆蓋距離來看，採用單向光纖直放站的網路性能優於採用全向光纖直放站的網路。In the Global System for Mobile communication for Railway (GSM-R), the optical repeater is widely used for tunnel coverage. However, the application of optical repeater brings in some co-channel interference for the network. This article analyzed this co-channel interference by the carrier-to-interference ratio and delay difference between the optical repeater and the base station. According to some simulations, by comparing the situation when the network is covered by Omni directional repeater to that when it is covered by the unidirectional repeater, to meet the demand of the carrier-to-interference ratio and the delay difference in GSM-R, it is shown that the former has a coverage distance of 1.5 km and the latter has a larger distance which should be lower than the radius of the base station, thus, the latter has a higher equipment utilization ratio.