Efficient communication through multi-channel time division multiple access for wireless sensor network

Abstract

Network congestion is an essential issue to be addressed in Wireless Sensor Network (WSN). Congestion degrades network performance in terms of packet throughput and throughput fairness. This is mainly caused by collisions and traffic imbalance. To reduce network congestion, three mechanisms to minimize the problem are proposed. Firstly, a load balancing strategy is deployed into mechanism of network self-organizing. The strategy addresses the issue of traffic imbalance. Secondly, the implementation of hop by hop flow control allowing sensor nodes to detect congested nodes and suspend their data transmission until the congested nodes are ready to receive data. Finally, a mechanism for reducing collisions through multi-channel Time Division Multiple Access (TDMA) is deployed in the Medium Access Control (MAC) layer. These mechanisms are realized in a dedicated WSN protocol called Multi-Channel Time Division Multiple Access – Cross Layer Protocol (MT-XLP). Design of the MT-XLP involved the Medium Access Control (MAC) and routing layers. The first layer manages the mechanisms for channel assignment, time slot allocation, and time synchronization to provide communication links and reduce collisions in the network. The second layer manages the load balancing and hop by hop flow control mechanisms. A series of experiments to measure packet throughput and index of throughput fairness were conducted using a number of sensor nodes and one sink node that installed with the MT-XLP protocol. The results were compared with result from the identical experiments that use IEEE 802.15.4/ZigBee protocol. The comparison showed that MT-XLP is able to provide packet throughput that are two times larger and has a larger index of throughput fairness in comparison to IEEE 8021.5.4/ZigBee.