Performance analysis of packet voice/data multiplexing systems

Abstract

In this dissertation work, the performances of statistical packet voice and voice/data multiplexers and cut-through switching technique for packet communication are studied extensively. We assume that in the packet voice/data multiplexer two separate queues are used for voice and data traffics, and each queue is served based on the first-in first-out (FIFO) rule. Also, we assume that voice traffic gets priority over data. For the performance analysis of the multiplexers, we divide the output link into a sequence of time slots. The voice signal is modeled as an (M+1)-state Markov process, M being the packet generation time in slots. This model reflects the slot-by-slot correlation property of talkspurt and pause and the periodic nature of packet generation when the voice input is in a talkspurt state. As for the data traffic, it is modeled by a simple Poisson process. In our discrete time domain analysis, the queueing behavior of voice traffic is little affected by the data traffic since voice signal has priority over data. Therefore, we first analyze the queueing behavior of voice traffic, and then using the result, we study the queueing behavior of data traffic. For the packet voice multiplexer, both input state and voice buffer occupancy are formulated by a two-dimensional Markov chain. Numerical results for the performance of the packet voice multiplexer have been obtained using the Gauss-Seidel iteration method. For the integrated voice/data multiplexer we use a three-dimensional Markov chain that represents the input voice state and the buffer occupancies of voice and data. With this model the numerical results for the performance of the packet voice data multiplexer have been obtained also by the Gauss-Seidel iteration method. The analytical results have been verified by computer simulation. From the results we have found that there exist tradeoffs among the number of voice users, output link capacity, voice queue size and overflow probability...