Performance models of handover protocols and buffering policies in mobile wireless ATM networks

Due to the connection-oriented nature of the asynchronous transfer mode (AT M), one of the challenges in mobile wireless ATM (WATM) systems is the mana gement of terminal handovers. When ATM connections are reestablished to fol low terminals moving between areas covered by distinct base stations, seaml ess handover protocols are necessary to guarantee that ATM cells are delive red to terminals in the correct order, with cell loss rate and delay that s atisfy the contracted quality of service (QoS). A promising approach to mee t QoS requirements is based on the use of handover buffers at the (destinat ion) base station, where transmitted cells are stored while the connection is being reestablished. Up to date, only simulation and experimental result s are available to determine the performance of such protocols and bufferin g schemes. This paper presents the first attempt to develop an analytical m odeling approach to estimate the performance of handover protocols making u se of handover buffers at the base station. By incorporating several approx imations, the proposed models allow designers to simultaneously take into a ccount numerous system parameters, including handover buffer size, sustaina ble and peak cell rates of the ATM connection, terminal offered load, and t ime needed to reestablish the ATM connection. Analytical performance predic tions are shown to closely match results of detailed simulation experiments , thus demonstrating the suitability of the proposed modeling framework for the selection of the most adequate solution to handle handover and provide the QoS required by end users.