Energy conservation is vital to wireless sensor networks (WSNs) due to the inherently limited sensor power budget. WSN routing consumes a lot of power, ergo sensor deployment density in the field is critical to routing and power efficiency. Due to the nature of WSNs, the challenge of energy conservation takes priority over other performance metrics.

This paper focuses on energy conservation of data routing over WSNs via the selection of the next-hop sensor. It divides the source sink route into circular regions, with the greater number of nodes in the sink region (nonuniform density). Sensed data is routed “in a multicast-traversal manner through multi-hop paths [over such regions].” Traditional mechanisms would randomly select the next hop from among neighboring nodes, leading to the unbalanced utilization of sensors. Another approach is to select the node with the largest residual energy, but this encounters a huge overhead in the exchanging nodes’ remaining energy levels.

The authors present an energy tie-breaking companion protocol based on a probabilistic spatial model that restricts the node selection to certain regions. They perform a thorough analysis, both mathematically and via simulation, but ignore other performance metrics, such as the packet delay/arrival ratio and network throughput in the context of presented solutions. In general, totally sacrificing the aforementioned metrics for energy conservation is not wise.

The paper fails to hint at approaches where each node decides for itself (via the function of its remaining energy) whether or not to be a part of the route, which are proven to be efficient.