Outage and energy level performance of layered CDMA wireless sensor networks with space diversity

In this paper, we analyze the performance of a single hop CDMA based wireless sensor network (WSN) using receiving antenna diversity at sink in terms of outage probability and bit error rate (BER). Correlation amongst signal and interferers is considered in large scale fading environment. We assume each node is power controlled while antenna diversity is present only at the sink. Energy consumption for successful delivery of information from source to sink is also evaluated. Two kinds of interference namely multiple access interference (MAI) and node interference (NI) are considered and an infinite automatic repeat request (ARQ) is assumed at link layer between a sending node and sink till successful delivery of packetized data. An appropriate model for evaluating quality of service (QoS) in terms of probability of outage and BER at sink is presented and validated by simulation. The effects of node density, correlation amongst signal and interferers, and number of antennas used for spatial diversity on outage probability and BER are investigated. The impact of antenna diversity on energy consumption is also indicated.