Research On The Key Technologies Of Routing Protocol Of Low Power And Lossy Networks

The rapid development of Internet of Things has further promoted the development of sensor network technology. The sensor network is a low power and lossy network (LLN). Nodes in low-power and lossy networks are limited in the memory, energy consumption, operating power and etc. How to enable the nodes to quickly establish the netwok topology and maintain a stable and reliable communication has attracted the interest of many scholars. Routing Protocol over Low power and Lossy Networks (RPL) proposed by the IETF's Routing Over Low-power and Lossy networks (ROLL) working group in a draft form in 2009 is a milestone in the routing of LLN. RPL not only provides a new idea for the routing mechanism of LLN, but also promotes the emergence of the- Internet of Things operating systems with RPL as the routing protocol, including Contiki and TinyOS.Based on the current research results of RPL, this paper deeply studies the objective functions and routing metrics used by objective functions .of RPL. As for the design of objective functions, this paper proposes algorithm of importing cross layer rectifier to the objective function with expected transmission times(ETX) as routing metrics and an objective function scheme of the combination of ETX and received signal strength index (RSSI) through fuzzy control system. In this paper, RPL simulation environment is built based on OMNeT++ simulation tool and its related mechanisms have been achieved. The performance improvement of RPL including packet delivery rate and mean end-to-end delay with the scheme has been proved. Especially, the performance improvement of large-scale networks is analyzed and discussed deeply. According to the switching rate of parent nodes, this paper verified that the scheme with fuzzy controlling can better balance the problem between RPL network performance and control overhead.