Joint optimization of connection-level and packet-level quality of service for wireless multimedia network

Abstract

Quality of Service (QoS) is an important issue in the next generation wireless networks providing multimedia services. To address this complex problem, we consider QoS in wireless multimedia networks at two levels: connection-level QoS, measured by the connection blocking and dropping probabilities, and packet-level QoS, measured by bandwidth, delay/jitter and loss sensitivity. First, different multimedia applications are classified into three service classes, namely CBR, VBR and UBR, according to their bandwidth, delay/jitter and reliability requirements. Then, network can choose appropriate resource management schemes for different service classes accordingly in order to meet their QoS requirements. CBR traffic requires a constant bit rate available during the entire lifetime of the connection. Both connection-level and packet-level QoS is guaranteed by connection-oriented service. Thus the joint optimization problem can be reduced to optimization of connection-level QoS (handoff dropping probability and new call blocking probability) for CBR traffic. VBR traffic could generally tolerate a certain amount of delay or packet loss, thus improve resource utilization by connection-less service. We formulate the trade-off of the QoS parameters on both levels based on a VBR traffic model, and find the near-optimal solutions for the joint optimization problem. UBR traffic does not have specified requirement on QoS, thus being served by the best-effort service. Network uses whatever the resource not being used to improve the overall system utilizations.