Handover based backlogged packet discard scheme for wireless ATM networks

We consider connection-oriented packet-switched wireless cellular networks such as wireless ATM networks. At a cell's base station, packets destined to mobiles are stored and sent to the cell's mobile stations across forward wireless channels. When a handover occurs, backlogged packets which are destined to the mobile station and which have not yet been delivered remain at the buffer of the old base station. For applications which are sensitive to delay fluctuations but are relatively tolerable to packet losses, (e.g., packetized voice and video streams), it is not effective forward these packets to the new base station. We thus consider a Backlogged Packet Discard Scheme under which all backlogged packets are discarded. In this manner, we eliminate additional packet delays caused by inter-cell rerouting of backlogged packets. In turn, this scheme leads to an increase of the packet loss level due to its dropping of the backlogged packets. To guarantee a pre-negotiated quality-of-service level, the incurred packet loss value must be limited. In this paper, we develop an analytical method for characterizing the statistics of the number of backlogged packets per handover, and derive an estimate for the probability of handover-induced packet loss. Using our analytical method, we investigate the effect of network parameters on the packet loss probability.