On the Performance of Multiplexing Real-Time VBR Traffic with Multiple Hysteresis Areas

Statistical multiplexing of variable bit rate real time (VBR-rt) traffic plays an important role in compressed multimedia applications. When employing statistical multiplexing for VBR-rt traffic, in order to achieve a better overall quality of service, it is expected for the system to accommodate more high rate calls and at the same time to maintain the stability of the bit rate. Although more thresholds result in a larger number of calls in better encoding bit rate, they produce higher bit rate fluctuations. By introducing hysteresis, the fluctuations can be mitigated at a cost of a slightly lower bit rate. In this paper, we propose a general model using a continuous time Markov chain to describe the dynamics of the system and to analyze its performance with multiple hysteresis areas. More specifically, our proposed model depicts a system operating at 3 encoding bit rates and involves multiple state-levels which are separated by hysteresis areas. The model is validated by simulations in Matlab. Based on the numerical results, we observed that with a proper configuration of the number and the length of hysteresis areas, better performance in both the number of high rate calls and the bitrate stability is obtained compared with the traditional approaches.