SiMple: A Unified Single & Multi-Path Routing Algorithm for WSNs with Source Location Privacy

Wireless Sensor Networks (WSNs) experience two different patterns of traffic with different requirements: 1) Event-driven traffic from sensor nodes to the base-station (BS) in the form of single-path uni-cast packets, and 2) Query-driven traffic from BS to sensors that better matches multi-casting and generates multi-path traffic. In this paper, we propose SiMple, a unified algorithm to jointly route single- and multi-path packets in WSNs. SiMple establishes a square destination area to control the degree of path multiplicity as well as the number of intermediate nodes between the source and destination nodes. When performing single-path routing, SiMple considers the direct line connecting source and destination nodes to select the closest sensor node to the line as the next carrier of the packet. Otherwise, SiMple directs packets towards the destination node(s) by exploiting multiple disjoint routes where the number of disjoint routes is controlled by the source node. In addition, SiMple introduces virtual source nodes to hide the location of the real source node, which is needed in asset monitoring applications. The conducted extensive NS-2 simulation experiments for mixed single- and multi-path packets confirm that SiMple results in a higher performance level and consumes lower energy when compared to the case of using two separate algorithms to individually route event and query packets.