An adaptive backoff algorithm for multi-channel CSMA in wireless sensor networks

Multiple channels have been widely used in wireless sensor networks (WSNs) for the improvement of network performance. Since the existing backoff algorithms proposed for single-channel MAC protocols are not suitable for multi-channel carrier sense multiple access (CSMA), we propose an ADaptive Backoff Algorithm (ADBA) for multi-channel CSMA in WSNs, which is able to improve energy efficiency, throughput, and fairness of random channel accesses. A novel feature of ADBA is the adaptability to traffic load, where every node tunes its backoff interval based on the estimation of real-time traffic load in WSNs. A near-optimal backoff interval can be generated using the number of competing nodes on one channel which can be estimated by the channel traffic load. Theoretical analysis indicates that ADBA can generate near-optimal backoff intervals that can maximize energy efficiency and throughput and improve fairness of random channel accesses, compared with other backoff schemes.