Low Energy and Low Latency in Wireless Sensor Networks

It is widely known that in wireless sensor networks (WSN), energy efficiency is of utmost importance. As a result, a common protocol design guideline has been to trade off some performance metrics such as throughput and delay for energy. This has also gone well in line with many applications for WSN. However, there are other applications with real-time constraints, such as those involved in surveillance or control loops, for which WSN still need to be energy efficient but also need to provide better performance, particularly latency. This paper presents a WSN cross-layer design approach involving the physical, MAC, and network layers that not only preserves the energy efficiency of current alternatives but also coordinates the transfer of packets from source to destination in such a way that latency and jitter are improved considerably. Our simulations show how LEMR (Latency, Energy, MAC and Routing), the proposed protocol, outperforms the well-known TMAC and S-MAC protocols in both performance metrics.