A cognitive wireless network is mostly deployed as wireless access network to optimize the utilization efficiency of radio resource by using multiple wireless systems. In such deployment, the network topology based on a tree structure can be efficiently and quickly constructed among the cognitive terminals (CT) by using the cognitive base station (CBS) as a root, to support the multihop communication. However, the original tree-based routing (TBR) protocol is designed to handle a single wireless system such as IEEE802.11a or lib, and thus can not be applied to the cognitive networks configured with multiple wireless systems, which may have the different bandwidths and transmission ranges. To solve this problem, we propose in this paper an efficient and practical protocol, called cognitive tree-based routing (CTBR) protocol, which extends and significantly enhances the ability of the known TBR protocol to enable it to support multiple wireless systems such as IEEE802.11g and IEEE802.11j. Simulation results reveal that our proposed CTBR protocol that utilizes the cognitive-aware link metric to select a route with the best end-to-end metric and an interface with the least local load for any source-destination pair, achieves much higher performance than the utilization of normal metric associated with the hop count.
['Bing Zhang', 'Yasuhisa Takizawa', 'Akio Hasagawa', 'Akira Yamaguchi', 'Sadao Obana']
Tree-Based Routing Protocol for Cognitive Wireless Access Networks