Efficient Packet Converge-Casting: Relieving the Sink Congestion in Wireless Sensor Networks

In this paper, we consider a wireless sensor network (WSN) where packets are forwarded to a central collector node (the sink). As all network traffic converges to this point, congestion builds up. We deal with this problem by assuming that the nodes around the sink are allowed to use a different, more efficient protocol for advancing data, namely a method designed to yield more throughput and reduce collisions, at the expense of some coordination efforts. We carry out extensive simulations, and compare our solution (which is composed of two protocols, one for the sink and its neighbors and one for the rest of the network) to a simpler collision avoidance approach used throughout the whole network. This allows to highlight the tradeoff between coordinating and interfacing two protocols (which requires better design, but achieves higher effectiveness) and using just one protocol (simpler, but more prone to congestion and losses). We show how our two-protocol solution outperforms the simpler one.