On the synchronization rate of distributed medium access protocols

Network synchronization can improve the performance of wireless networks in several ways, such as by enabling the use of slotted medium access protocols. Distributed synchronization is an appealing technique to achieve network synchronization in wireless ad-hoc and sensor networks. At the MAC layer, different signaling techniques and medium access protocols may be employed for synchronization purposes. Here we evaluate the impact of the use of reservation, contention and superposition access protocols on the convergence rate of distributed synchronization based on Distributed Digital Locked Loops (D-DLL). Contention and superposition are random access protocols, and almost sure convergence can be guaranteed by studying convergence in the mean. Also, an approximation of the convergence rate of random access protocols is proposed based on numerical results. Finally, the performance of the considered protocols over a regular square grid network is compared via simulations.