Patent Document ID: 20140355628
Application ID: 13909031
Patent Flag: 0

Claim One:
1. A computer-implemented recursive time synchronization protocol method for a wireless sensor network (WSN), comprising the steps of: electing a single reference node i for offset and drift compensation, the electing being limited to nodes that are clusterheads; calculating a time read by a logical clock of the i th node of the WSN, the calculation utilizing the relation: 
 C i ( t )=α i +β i t, where α i is the clock offset deviation from ideal time at the reference time t=0 and β i , is the frequency of the clock; re-synchronizing the clock within a time T≦δ/2ρ, where δ is a relative offset and ρ is a skew rate; estimating the relative offset and a drift of the clock, thereby re-synchronizing the clock infrequently; initiating a time synchronization request, the time synchronization request being initiated by any node in the WSN; recursively forwarding the time synchronization request to the reference node, thereby establishing a request-path; using a REP (reply to time synchronization) message to forward the time T back to the initiating node via the request-path; and compensating the time T with a propagation delay time at each hop in the request-path, thereby time synchronizing all WSN nodes in the request-path.