GSM-R光纤直放站应用简要分析

Brief Analysis on Application of Optic-fiber Repeater in GSM-R Network

研究目的:光纤直放站在GSM-R网络中的应用越来越广泛,如何合理应用光纤直放站,使之更好地为GSM-R网络服务,需要对光纤直放站的特性进行研究。研究方法:本文主要从理论上对光纤直放站上行噪声对基站的影响和时延限制等方面进行了简要分析,并对光纤直放站的工程应用提出了一些建议。研究结果:通过分析得出,每个基站所带光纤直放站不宜超出4个,否则将引起基站灵敏度的严重下降。基站和光纤直放站采用空间波覆盖时,光纤直放站宜采用单定向天线向远离基站的方向覆盖。在采用LCX的区段,由于时延限制,提高光纤直放站输出电平不能增加覆盖范围。另外,基站和光纤直放站之间的LCX最好不作断开。研究结论:光纤直放站在GSM-R工程中不仅需要考虑覆盖电平。

Research purposes： The optic - fiber repeaters are widely used in the GSM - R network. How to apply it reasonably and make it serve better in the GSM - R network needs further analysis and research. Research methods：An analysis has been theoretically made of influences of the uplink noise from the optic - fiber repeater on the repeater and time - limited delay, etc. And some advices have been put forward on application of optic -fiber repeaters in the GSM -R engineering. Research results：It has been pointed out through analysis that not more than four optic -fiber repeaters shall be set in each BTS. If more than four, this will reduce the sensitivity of BTS. The BTS and optic - fiber repeater shall be covered by spatial waves while the optic - fiber repeater shall be better to be covered by the single - directional antenna far from the BTS. In the LCX section, the coverage range cannot be increased due to the time- limited delay by increasing the output - electrical level of optic - fiber repeaters. It is better not to cut off the LCX between the BTS and the optic - fiber repeater. Research conclusions： In the GSM -R engineering, not only the electrical level would be considered, but also the uplink noise and the time- limited delay would be considered.