Effect of End-to-end Delay on Lifetime and Average Bit Error Rate in Directional Antenna Based Wireless Sensor Networks

This paper evaluates the effect of end-to-end delay on lifetime and the average bit error rate for wireless sensor networks where each sensor node sends its data to sink via directional antennas. Using Mixed Integer Programming, lifetime is optimized for circular network topologies with different numbers of nodes. Using both directional and omnidirectional antennas, different end-to-end delay restrictions are applied to the same sensor network to examine the effect on lifetime and average bit error rate. When delay restriction is relaxed, an increase in lifetime and a decrease in average bit error rate are observed for both antennas. In this case, the directional antenna benefits more from relaxing the delay restriction. In the end, an optimal end-to-end delay was determined which provides sufficient lifetime and bit error rate while taking into account data freshness.

I. Introduction

WIRELESS Sensor Networks (WSNs) are spatially dispersed sensors that are used to detect physical conditions of the environment and transfer collected data to a central location for communication purposes. In a WSN, data is forwarded to a sink node from sensor nodes, which can generate their own data in addition to acting as relays [1] . Even though they were initially designed for military purposes, they have broad usage areas in the modern world such as smart home systems, vehicle tracking, and medical imaging [2] .