Effect of the Feedback Function on the QoS in a Time Space Priority with Active Queue Management

The basic idea behind an active queue management (AQM) is to sense the congestion level within the network and inform the packet sources about, so that they reduce their sending rate. In literature a lot off mechanisms of AQM are studied. But there are not used in the context of the DiffServ architecture where different types of packet with different requirements of QoS share the same link. In this paper, we study an access control mechanism for RT and NRT packets arriving in a buffer implemented at an end user in HSDPA. The mechanism uses thresholds to mange access in the buffer and gives access priority to RT packets. In order to control the arrival rate of the NRT packets in the buffer an active queue management is used. We study the effect of the feedback function on the QoS parameters for both kinds of packets .Mathematical description and analytical results are given, and numerical results show that the proposed function achieves higher QoS for the NRT packets in the system.