Study On Subnet Partition And Timing Schedule-Based Wireless Sensor Network Multi-Channel MAC Protocol

Wireless Sensor Network (WSN) is a distributed, multi-hop network composed of massive micro-sensor placed densely in the monitoring area in wireless, self-organizing manner, aiming to collaboratively sense, collect and process the information from the sensed objects in the monitoring area, and then report to the observer. As an emerging data acquisition technology, WSN has played a great role in many applications such as military and national defense, health care, environmental monitoring, smart home, etc.Research into WSN mainly focuses on routing protocols, MAC protocols, positioning technology, data aggregation technology, etc. WSN MAC protocols control the allocation of the wireless media and determine the timing of data sending and receiving, which build the infrastructure of the network systems and have great influence upon network performances. In traditional WSN MAC protocols, energy efficiency may be considered to be the most important concern whereas utilizing bandwidth and maximizing throughput are of secondary importance. However, recent applications, such as structural health monitoring, require high amounts of data to be collected at a faster rate, which presents a greater challenge to the network throughput.Taking into account that transceivers equipped by WSN nodes have supported multi-channel, the paper proposes a multi-channel WSN MAC protocol based on subnet partition and timing schedule. First, according to the rule of minimum interference value, the whole network is divided into multiple tree-based subnets to reduce intra-subnet interference, each of which takes a different channel to eliminate inter-subnet interference. Second, timing schedule-based media access is adopted in individual subnets and all of the neighboring nodes in a 2-hop radius of some node try to select different sending timeslots, which achieves non-collision transmission.At last, the proposed protocol is analyzed in detail and compared to single-channel CSMA protocol and multi-channel CSMA protocol. The simulation results manifest that with a proper estimation of the node density the proposed protocol can achieve high throughput and low latency while keeping energy efficient.