A timestamp-sensitive scheduling algorithm for MPEG-II multiplexers in CATV networks

Abstract

To achieve smooth display of MPEG-II programs in the residential cable TV networks, we present a timestamp-sensitive scheduling algorithm for MPEG-II multiplexers. The deadline-driven scheduler maintains, for each program stream, a counter and a timestamp to record and determine how many Transport Stream (TS) packets should be transmitted before the current scheduling cycle ends. The decoding timestamp (DTS) of TS packets is used to update the counter in order to prevent deadline violation. This algorithm is compared numerically with the timestamp-insensitive algorithm which runs constant-bit-rate (CBR) scheduling. The trace-driven simulation shows that the deadline violation of our timestamp-sensitive scheduling is much lower than CBR's and well controlled for programs with various degrees of burstiness. We also show that the algorithm can be further improved by adding a scheme to prevent buffer underflow and overflow at multiplexers and set-top-boxes, respectively.