基于ROF的宽带无线接入网及切换技术研究

摘要

With the demand of RF bandwidth and the limited availability of the RF band, ROF access network is proposed. It combines wireless communication and optical communication, holding the high bandwidth and strong flexibility. Handof based on static virtual cell zone was proposed to enlarge the cell zone and reduce the handoff frequency. Static virtual cell zone improves the performance of handoff, but constrains the channel resources. In this paper, dynamic channel reservation is applied to further reduce cal drop rate. Through M/M/c model and mathematic analysis, simulation results show that call drop rate can be further reduced.%ROF宽带无线接入网是针对日益增长的带宽需求和紧张的低频段资源而提出的，是光纤通信和无线通信的结合，具有高带宽和灵活性强等优点。目前，用于实现ROF接入网切换的主流方法是采用静态扩展单元，即在用户移动前，将相邻的若干小区合并，形成扩展单元，增大小区覆盖范围，避免频繁切换。由于这种做法会使得扩展单元中的信道资源相对紧张，为了有效利用信道资源，并在静态扩展单元的基础上进一步降低切换掉话率，本文将动态信道预留方法应用于静态扩展单元中，并进行了相关的数学分析。同时设置不同的网络负载进行仿真，结果表明：在新呼叫阻塞率可接受范围内，采用动态信道预留方法，可以在静态扩展单元的基础上进一步降低切换掉话率。