On the capabilities of packet discarding mechanisms in wireless networks

It is widely recognized that mobility is one of the main features of wireless networks. In order to be able to remain reachable within a given geographic area (cell), a mobile terminal has to keep within the reach of a base station. As the mobile terminal moves from cell to cell, the station has to connect to the base station covering the new cell. A handover mechanism defines the steps involved in the transfer of all the information and resource allocation enabling a mobile terminal to remain connected to the wireless network infrastructure. In this article, we carry out a performance evaluation of various buffer management schemes used to compensate for service disruption caused during the handover phase. All these schemes have been modelled and simulated using the NIST simulation package. We present a comparison in terms of packet losses. In the simulation, we make use MPEG-4 video sources to evaluate the various buffer management mechanisms. The video is encoded using a hierarchical scheme. Under the scenario under consideration, the push-out mechanism exhibits the best results.