The Implications of Reliable Data Delivery for Performance in Wireless Sensor Networks

Messages transported within a sensor network are subject to losses due to a number of factors. These factors include losses in the wireless channel, MAC layer collisions, node error or failure and losses due to incorrect routing. This paper describes these sources of data loss and discusses the various strategies available to prevent data loss. The effectiveness of each of the strategies to prevent the different types of data loss is discussed. In particular, it is examined how the implementation of any particular scheme affects network performance. Here we define performance as accurate sensing of phenomena, reliable delivery of data, and the timeliness of data delivery. The implementation of reliability mechanisms in a sensor network can adversely effect the timeliness of data delivery thus presenting a design trade off in this area. Our principal contribution is the identification and description of this problem. Furthermore, we discuss the trade offs between reliability and delay and investigate the need for a framework to aid in WSN design in this area. It is our intention to implement and evaluate such a framework in our ongoing