Improving UDP performance using intermediate QoD-aware hop system for wired/wireless multimedia communication systems

Multimedia communication in wireless networks is challenging due to the inherent complexity and constraints of multimedia data. To reduce the high bandwidth requirement of video streaming, videos are compressed by exploiting spatial and temporal redundancy thus yielding dependencies among frames as well as within a frame. Unnecessary transmission and maintenance of useless packets in the buffers cause further loss and degrades the quality of delivery (QoD) significantly. In this paper, we propose a QoD-aware hop system that can decide when and which packets could be dropped without degrading QoD. Moreover, the transmission of useless packets causes network congestion and vain payment by the wireless system subscriber. In this paper, we focus on two types of frame discarding policies to maintain QoD; partial frame discarding policy (PFD) and early frame discarding policy (EFD). PFD policy discards the succeeding packets of a frame if a packet of the frame cannot be served. On the other hand, in EFD policy when it is likely to fail to serve packets of a frame (based on a threshold), the subsequent packets of the frame are discarded. We first provide an analytical study of average buffer occupancy based on these discarding policies and show the closed-form expressions for average buffer occupancy. We then perform our simulations by implementing a Markovian model and measure the frameput (the ratio of number of frames served) rather than the number of packets served.