Detection of time-varying directional flows in wireless networks

The problem of detecting packet flows between two nodes in a wireless network is considered. Especially, the transmission timings of two nodes are recorded, and their transmission rates can be time-varying (piecewise constant). Based on the timing measurements, our objective is to detect the presence of packet flows between them. Two different scenarios are considered; the first is that a flow may exist in only one specific direction, and the other is that a flow may exist in any direction. For each case, a detection algorithm is provided, and for the latter scenario, an additional algorithm aimed at estimating the direction of the underlying flow is proposed. When the transmission processes are nonhomogeneous Poisson processes, under certain conditions, our algorithms are proved to be consistent. The algorithms are tested using the MSN Voice over IP (VoIP) traffic and the synthetic Poisson traffic.