Research Area:  Internet of Things
We propose a novel cross-layer scheme to reduce energy consumption in wireless sensor networks composed of IEEE 802.15.4 IoT devices with adjustable transmit power. Our approach is based on the IETF-s Routing Protocol for Low power and lossy networks (RPL). Nodes discover neighbors and keep fresh link statistics for each available transmit power level. Using the product of ETX and local transmit power level as a single metric, each node selects both the parent that minimizes the energy for packet transmission along the path to the root and the optimal local transmit power to be used. We have implemented our cross-layer scheme in NG-Contiki using the Z1 mote and two transmit power levels (55mW and 31mW). Simulations of a network of 15 motes show that (on average) 66 percentage of nodes selected the low-power setting in a 25m area. As a result, we obtained an average reduction of 25 percentage of the energy spent on transmission and reception of packets compared to the standard RPL settings where all nodes use the same transmit power level. In large scenarios our approach provides better results in dense networks where reducing the transmit power of nodes does not translate into longer paths to the root nor degraded quality of service.
Author(s) Name:  Rafael Estepa; Antonio Estepa; German Madinabeitia; Ernesto Garcia
Journal name:  IEEE Access
Publisher name:  IEEE
Volume Information:  Volume: 9, Pages: 120689 - 120703
Paper Link:   https://ieeexplore.ieee.org/abstract/document/9523554