An efficient distributed synchronization method for TD/CDMA based Mobile Ad Hoc Networks

Mobile ad Hoc network (MANET) and sensor networks have no fixed infrastructures such as Base Stations and Towers, and have limited bandwidth across the network elements. They use multi-hop radio communications to deliver multi-service (voice, data, and video) information. Each network element can either send a packet or receive a packet but not both. Therefore, synchronization between radios must be achieved for every packet scheduling time with minimal amount of time to ensure QoS provisioning. This paper presents a novel distributed synchronization scheme for radio communication in a TD/CDMA based MANET and Sensor Networks. The scheme is designed using a first order Digital Phase locked loop (DPLL) which performs the dasialocal lockingpsila at each receiver radio in a cluster of radios. The method exploits the clock drifts in each local clock of a radio with reference to which the local stored clocks are phase adjusted within the loop of the DPLL. A parameter called dasiaphase adjustment indexpsila represented by dasiaNpsila- an integer; is defined and is used as the scaling value of the local clock frequency. Analytical results have been shown to yield an effectively reduced size of overhead when compared to the overhead sizes dedicated for synchronization purpose in IEEE 802.11. The results have been verified by simulation in MATLAB.