A Contention-based Transmission Strategy for distributed detection based on wireless sensor network

A channel-sharing method was proposed to improve the bandwidth and energy efficiency per detection task in wireless sensor network. The sensor nodes transmitted their log-likelihood ratios (LLR) to the fusion center in approximately descending order of the absolute value of their LLRs by modifying the value of backoff timer and frame interval according to the values of their LLRs. Simulation results show that, compared with the method using dedicated channels to transfer data to the fusion center, the occurrence of the discrepancy between the global decisions of the two methods is less than 50 per a million tests, and the channel bandwidth of the system is reduced to1/N of the original. The proposed scheme can save transmissions more than 20%, compared with the optimum unconstrained energy approach. Therefore, the proposed method fulfills the evident decrease in communication bandwidth, at a very small cost of detection performance.