Abstract: In order to guarantee the quality of service for spectrum handoff, a multi-hop spectrum handoff algorithm is presented for the centralized cognitive radio networks, in which spectrum heterogeneity has been taken into account. A user mobile model is developed to predict the usage time of allocated channel, the different processing approaches are designed for different types of nodes in the routing path, and the cognitive radio base station selects the optimal path according to the predicted shortest path time and time stamp. Simulation results reveal that the proposed multi-hop routing algorithm can considerably decrease the handoff blocking probability, and the channel utilization is also enhanced. Moreover, further simulation results show that cognitive radio node’s mobility plays an important role in the channel available usage time.

Key words: cognitive radio, spectrum heterogeneity, spectrum handoff, multi-hop routing

摘要： 针对集中控制认知无线网络，在考虑频谱异构特性的同时，为保证频谱切换业务的服务质量，提出了一种多跳频谱切换算法。通过建立用户移动模型来预测分配信道的可使用时间；设计出路径中不同类型节点的路由处理方法；认知基站根据预测最短路径时间和路由请求包中的时间戳来选择最优路径。仿真结果表明，提出的多跳频谱切换算法能够大大降低切换阻塞概率，提高信道利用率；用户移动对信道可使用时间有着显著的影响。

关键词: 认知无线电, 频谱异构, 频谱切换, 多跳路由