Capacity analysis of multi-hop wireless sensor networks using multiple transmission channels: A case study using IEEE 802.15.4 based networks

Designing a multi-hop wireless network is a challenge mainly because of high bit error rates and the inherent broadcast nature of the medium creating interference. To improve the capacity, protocols based on spatial reuse of frequencies with multiple orthogonal channels have been introduced. This is particularly useful in complete wireless environments such as wireless mesh networks and wireless sensor networks (WSN). Based on initial testbed experiments on WSN testbeds, we show that there is a gap between reality and simulation models due to overheads in implementing these protocols. In order to support QoS guarantees in critical paths for such networks, we present a generic channel allocation scheme based on k-distance coloring problem, for multiple channel networks. The scheme is designed keeping in mind the real time deployment issues in wireless networks. We report the results from experiments conducted using a IEEE 802.15.4 based testbed consisting of Xbow MicaZ nodes and results obtained using the OMNET4 simulation environment.