A dense multi-hop wireless sensor network usually faces a scalability problem since the distance between cluster heads could be high, which causes relatively low throughput and high latency between the sink node and cluster heads. In this paper, we propose a heterogeneous structure for a dense WSN using IEEE 802.15.4 and IEEE 802.11 networks to increase throughput and reduce latency. However, since both networks usually share the same unlicensed 2.4GHz band, the transmissions between them can cause inter-network interference if overlapping channels are used. To mitigate this interference, we further present a novel algorithm named Blank Burst (BB), which exploites the difference in transmission rates of the two standards to avoid packet collisions. To evaluate the performance of this dense heterogeneous WSN and the effectiveness of the proposed algorithm, a new OPNET simulation model was developed. Simulation results show that heterogeneous WSNs are superior to homogeneous WSNs in terms of throughput and latency. This algorithm can also effectively alleviate inter-network interference, thereby significantly improving the overall system performance.
['Dong Chen', 'Jason Brown', 'Jamil Y. Khan']
An interference mitigation approach for a dense heterogeneous wireless sensor network