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局域多点分布式系统(LMDS)是一种宽带无线点对多点通信系统。该系统利用目前还很少使用的20GHz至40GHz的频谱,用无线电波作为传输媒介,提供双向语音、数字、Internet及视频传输服务。本文首先讨论LMDS系统采用的无线连接介质访问方法及调制方法,之后从LMDS系统可提供的数据传送输率、用户接入个数两方面对LMDS系统的容量进行分析。分析结果表明,LMDS系统若采用FDMA与TDMA相结合的介质访问方法,则能同时满足用户对数据传送率及接入数的需求。
Local Multipoint Distributed System (LMDS) is a broadband wireless point-to-multipoint communication system. The system utilizes the 20 GHz to 40 GHz spectrum, which is still rarely used, and uses radio waves as a transmission medium to provide two-way voice, digital, Internet and video transmission services. This paper first discusses the wireless access medium access method and modulation method adopted by the LMDS system, and then analyzes the capacity of the LMDS system from the data transmission rate and the number of user access that the LMDS system can provide. The analysis results show that the LMDS system can meet both the data transfer rate and the number of access requests by using the media access method combined with FDMA and TDMA.