Multi-Hop Synchronization at the Application Layer of Wireless and Satellite Networks

Time synchronization is a key issue in wireless and satellite networks; time-stamping collected data, tasks scheduling or efficient communications are just some applications. From all the existing techniques to achieve synchronization, those that work at the MAC layer and can precisely timestamp sync messages are the most accurate. However, working with standard protocols, usually prevents the user from accessing lower layers and consequently reduces accuracy. Receiver-receiver schema improves time-stamping performance because it eliminates the biggest non-deterministic error at the sender side; the medium access time. Nevertheless, utilization of these methods in multi- hop networks usually requires an extra amount of traffic. In this paper we present a method which allows accurate synchronization of large multi-hop networks such as satellite networks working at the application layer while keeping the message exchange to the minimum. Through an exhaustive experimentation, we show the protocol´s performance and analyze the factors that influence synchronization accuracy the most.