Performance analysis of a differentiated services over wireless links

This article analyses a differentiated services scheme accounting for wireless link features like fast and slow fading, error control and mobile power profile. The approach brings insights into the interaction between network-level QoS and link-level parameters. A buffer management scheme based on RIO (RED - random early detection - with in/out) and a scheduling scheme based on mobile power level and maximum RIO threshold are used to provision differentiated services over wireless IP links. The tail distribution of the bivariate semi-Markov process modelling the wireless link state and buffer occupancy is computed using matrix analytic methods. The results are used to examine the loss rate and expected queuing delays of packets. Packets are categorized into five classes based on QoS requirements and mapped onto UMTS/3G traffic and standard DiffServ per-hop behaviours. The proposed scheme guarantees a low average packet queuing delay and a low packet loss rate simultaneously.