Multi modal wireless sensor networks based on wake-up radio receivers: An analytical model for energy consumption

Traditionally, sophisticate power-aware wake-up techniques have been employed to achieve energy efficiency in Wireless Sensor Networks (WSNs), such as low-duty cycling protocols using a single radio architecture. These protocols achieve good results regarding energy savings, but they suffer from idle-listening and overhearing issues, that make them not reliable for most ultra-low power demanding applications, especially, those deployed in hostile and unattended environments. Currently, Wake-up Radio Receivers (WuRx) based protocols, under a dual-radio architecture and always-on operation, are emerging as a solution to overcome these issues, promising higher energy consumption reduction compared to classic wake-up protocols. By combining different transceivers and reporting protocols regarding energy efficiency, multimodality in WSNs is achieved. This paper presents an energy consumption estimation model that considers the behavior and performance of wake-up protocols based on WuRx in multi-hop communications under several cases instead of traditional low-duty cycling schemes. The results show that the WuRx with addressing does not significantly reduce the energy consumption compared to WuRx without addressing. In some cases, classic low-duty cycling protocols outperform WuRx based protocols, but in most cases, it is contrariwise, giving a strong motivation for considering multi-modal approaches in WSNs.