Power Control and Cross-Layer design of RPL Objective Function for Low Power and Lossy Networks

Wireless Industrial IoT applications demand realtime service requirements over low-power and lossy networks (LLNs). Therefore, designing networks based on open standards which meet the specified quality of service requirements for such low power and lossy networks is important. In this paper, we design an objective function for LLNs using the IPv6 routing protocol for LLNs (RPL) with 6LoWPAN adaptation layer over IEEE802.15.4 MAC and PHY. We address the problem of meeting latency and reliability requirements using a combination of route design and power control. Since RPL uses objective functions (OFs) at each node to build routes, we propose an OF which meets the latency and reliability requirements using a fuzzy logic based combination of expected transmission count (ETX) and estimated latency across protocol layers. We also propose an associated power control mechanism which when used along with this OF gives better packet delivery ratio and smaller latency by reducing the latency due to CSMA channel access under sizable traffic. We compare the performance of the proposed OF and power control scheme with the existing schemes using the Cooja simulator.