Fast mobility support in low-power wireless networks: smart-HOP over RPL/6LoWPAN

摘要

With the emergence of low-power wireless hardware new ways of communicationwere needed. In order to standardize the communication between these low powereddevices the Internet Engineering Task Force (IETF) released the 6LoWPAN stand-ard that acts as an additional layer for making the IPv6 link layer suitable for thelower-power and lossy networks. In the same way, IPv6 Routing Protocol for Low-Power and Lossy Networks (RPL) has been proposed by the IETF Routing Over Lowpower and Lossy networks (ROLL) Working Group as a standard routing protocolfor IPv6 routing in low-power wireless sensor networks. The research performed inthis thesis uses these technologies to implement a mobility process.Mobility management is a fundamental yet challenging area in low-power wirelessnetworks. There are applications that require mobile nodes to exchange data witha xed infrastructure with quality-of-service guarantees. A prime example of theseapplications is the monitoring of patients in real-time. In these scenarios, broadcast-ing data to all access points (APs) within range may not be a valid option due tothe energy consumption, data storage and complexity requirements. An alternativeand e cient option is to allow mobile nodes to perform hand-o s.Hand-o mechanisms have been well studied in cellular and ad-hoc networks.However, low-power wireless networks pose a new set of challenges. On one hand,simpler radios and constrained resources ask for simpler hand-o schemes. On theother hand, the shorter coverage and higher variability of low-power links require acareful tuning of the hand-o parameters.In this work, we tackle the problem of integrating smart-HOP within a standardprotocol, speci cally RPL. The simulation results in Cooja indicate that the pro-posed scheme minimizes the hand-o delay and the total network overhead. Thestandard RPL protocol is simply unable to provide a reliable mobility support sim-ilar to other COTS technologies. Instead, they support joining and leaving of nodes,with very low responsiveness in the existence of physical mobility.