Abstract:
In Flooding Time Synchronization Protocol (FTSP), the propagation speed of the flood is slow since each node waits for a given period of time in order to propagate its time information about the reference node. It has been shown that slow-flooding decreases the synchronization accuracy and scalability of FTSP drastically. Alternatively, to answer the question of whether it is possible for sensor nodes to synchronize to a reference node while they optimize the clock skew between their neighboring nodes at the same time, a novel time synchronization protocol, namely External Gradient Time Synchronization Protocol (EGSync) is used. Thus it synchronizes sensor nodes to the clock of a reference node will be optimizing synchronization error between neighboring nodes at the same time. In order to achieve this goal, EGSync executes an agreement protocol among the neighboring sensor nodes and forces them to agree on a common clock value and clock speed. Additionally a reference node floods its time information into the network. In EGSync, each sensor node synchronizes to a reference node by using time information flooded by this node as well as synchronizes to its neighbouring nodes by employing the agreement algorithm which all nodes agree on a common logical clock speed within a stable time on a whole network. The main objective of gradient time synchronization protocol is to minimize the clock skew between neighbouring nodes.
Keywords: Slow Flooding, Least Squares, Clock Speed Agreement, FTSP