CS-MNS: Analysis and Implementation

Wireless sensor networks (WSNs) consist of numerous nodes gathering observations and combining these observations. Often, the timing of these observations is of importance when processing sensor data. Thus, a need for clock synchronization arises in WSNs. The clock sampling mutual network synchronization (CS-MNS) algorithm has been proposed to fulfil this role. Analytical results are given that show, in the absence of initial offset errors, that the network clocks converge. In the general case, conditions are presented under which the clock rates show convergent behaviour. The CS-MNS algorithm is improved through the addition of a bias term to control initial divergence. Numerical simulation is used to explore the behaviour of CS-MNS for different network topologies. The CS-MNS algorithm is implemented under TinyOS and its performance experimentally evaluated. The results show that CS-MNS behaves as pedicted by analysis and simulation, and acheives significantly better clock synchronization performance than the flooding time synchronization protocol (FTSP).