Collision-free and low delay MAC protocol based on multi-level quorum system in underwater wireless sensor networks

摘要

Underwater wireless sensor network (UWSN) is a typical application of wireless network in underwater environment, which mainly uses acoustic communication at present. However, due to the characteristics of high bit error rate, very limited bandwidth and high transmission delay, the data transmission collision of underwater communication is very serious. In order to reduce transmission collision and improve network performance, we propose a collision-free time slot scheduling MAC protocol based on multi-level quorum system for high loaded UWSNs. The proposed protocol can allocate different time slots for nodes in the same collision area, while realize space reuse for nodes in different collision areas. Considering the unbalanced data transmission of each node, a multi-level quorum system algorithm is constructed for fairness, which can allocate time slots on demand according to the data transmission amount of each node. In order to ensure reliable transmission of data, a light weight retransmission mechanism is designed to reduce the impact of long delay on channel duty cycle. Simulation results prove that the proposed MAC protocol can effectively avoid transmission collision, reduce transmission delay, improve system energy efficiency, and have good adaptability for different network topologies.