The integration of heterogeneous wireless access technologies has numerous
issues for multimedia applications, such as to smoothly continue over new
connections without any service disruption during vertical handovers. We
propose State-Aware Feedback extension to Datagram Congestion Control
Protocol (DCCP) that meets QoS requirements of multimedia applications
throughout the handover process. We consider movement of mobile subscribers
among heterogeneous access technologies from highly unstable to more stable
environment and model their mobility patterns as Uniform, Pareto, and
Exponentially distributed. We present detailed analysis on the performance of
proposed mechanism in terms of resuming transmissions during the handover
process. In particular, we propose Markov model of TFRC capturing TCP
timeouts, loss rates, and no-feedback timer expirations. We validate the
proposed analytical model through simulations and show that it accurately
predicts various congestion events that may happen during the handover
process. We then evaluate the performance of S-TFRC via both simulations and
analytical model and observe the sender rates and throughputs achieved. We
also consider transmission delays and transmission rates as performance
metrics and compare performance of S-TFRC with the standard TFRC. Our results
show that S-TFRC is capable of providing better QoS to multimedia
applications than standard TFRC by significantly reducing transmission delays
and provides better throughput to multimedia applications.