On-Demand QoS Routing in Multihop Mobile Networks†

The emergence of nomadic applications have recently generated a lot of interest in next generation wireless network infrastructures (e.g., the 3G EGPRS (Enhanced Gen- eral Packe tR adio Services), UMTS/IMT-2000, etc.) which provide differentiated service classes. So it is important to study how the Quality of Service (QoS), suc ha s p acke tl oss and bandwidth, should be guaranteed. T oa ccomplish this, we develop an admission control scheme whic hc an guarantee bandwidth for real-time applications in multihop mobile net- works. In our scheme ,ah ost need not discover and maintain any information of the network rces status on the routes to another host until a connection request is g enerated for the communication between the two hosts, unless the former host is offering its services as an intermediate forwarding station to maintain connectivity between two other hosts. This band- width guarantee featur ei s important for a mobile network (e.g., wireless LAN, EGPRS, etc.) to interconnect wired net- works with QoS support (e.g., ATM, Internet, etc.). Our con- nection admission control scheme can also work in a stand- alone mobile ad hoc network for real-time applications. This control scheme contains end-to-end bandwidth calculation and bandwidth allocation. Under suc has cheme ,t he source (or the ATM gateway ,o r Enhanced Serving GPRS Supporting Node) is informed of the bandwidth and QoS available to any destination in the mobile network. This knowledg ee nables the establishment of QoS connections within the mobile net- work and the efficient support of real time applications. In case of ATM interconnection, the bandwidth information can be used to carry out intelligent handof fb etween ATM gate- ways and/or to extend the ATM virtual circuit service to the mobile network with possible r enegotiation of QoS parame- ter sa t the gateway (e.g., Enhanced Gateway GPRS Support- ing Node). We examine via simulation the system perfor - mance in various QoS traffic flows and mobility en viron- ments. Simulation results suggest distinct performance advantage so f our protocol calculating the bandwidth infor - mation. Furthermore, ''on-demand' 'f eatur ee nhances the performance in the mobile en vironment because the source can keep mor ec onnectivity with enough bandwidth to a