Scheduling algorithm for MPEG-2 TS multiplexers in CATV networks

We study the scheduling algorithm for multiplexers in CATV networks. First we propose the scheduling matrix concept, and then two kinds of scheduling algorithms are given, which are described with the scheduling matrix. Especially, we focus on the VBR scheduling algorithm being able to achieve a better display of the MPEG-2 program in CATV networks. The scheduler applying our VBR scheduling algorithm maintains, for each input stream, a counter to determine how many TS packets should be transmitted in the current scheduling cycle (one frame period) in order to prevent deadline violation. The real-time bit rate of each input stream is used to update the parameters of the scheduling matrix. Our VBR scheduling algorithm is compared numerically with the traditional CBR scheduling algorithm. The results of the simulation show that our VBR scheduling algorithm can achieve significantly lower delay, i.e., deadline violation probability, in comparison with the CBR scheduling algorithm. Also it is shown that a higher utilization of bandwidth can be achieved by means of our VBR scheduling algorithm than by the CBR scheduling algorithm.