Dynamic Spectrum Access Based Cooperative Relay Approach For Real-time Transmission Over Multi-hop Wireless Ad hoc Networks

摘要

Owing to bursty nature of source data, even an ad hoc network with low average traffic may suffer abrupt heavy traffic, which then increases difficulty in realizing real-time transmission. In this paper, we construct a hybrid system consisting of plural ad hoc networks, which are defined as primary radio networks (PRNs), and a secondary radio network (SRN). Aiming to provide a solution to real-time transmission, a cooperative relay scheme based on dynamic spectrum access (DSA) is investigated. Two types of cognitive relay technologies defined as dynamic cognitive relay and limited cognitive relay have shown different characteristics: the former has higher flexibility to dynamic traffic while the latter relies less on cooperation of SRN. Simulation-based evaluation shows that compared to limited cognitive relay, dynamic cognitive relay is more effective in realizing real-time traffic, but suffers higher channel switching rate. We then propose a smart interference control method to improve immunity of primary terminals to interference caused by cognitive relay, which can reduce channel switching rate and improve success rate at the same time.