The impact of fading and shadowing on the network performance of wireless sensor networks

Most ad hoc and sensor network research assumes idealised radio propagation models without considering fading and shadowing effects. Experimental results have shown that many well-designed protocols will fail simply because of fading and shadowing experienced in a realistic wireless environment. While fading and shadowing for radio propagation are well understood in the wireless communication community, they are rarely studied in network level research for wireless sensor networks. This paper studies the fading and shadowing effects on the performance of different systems for wireless sensor networks. We show that fading and shadowing can have a significant influence on network performance. We study and compare network performance for three different systems: (1) a multichannel CDMA system; (2) a pure CDMA system; (3) a contention-based system. Through discrete event simulation (using ns-2), we show that the multichannel CDMA system outperforms the pure CDMA system as well as the contention-based system under fading and shadowing environments.