The performance of an asynchronous transfer mode (ATM) multiplexer is evaluated, with the aggregate arrivals modeled as a Markov-modulated Poisson process (MMPP). The analysis is based on two simplifying assumptions: the probability that the MMPP goes through multiple state transitions between two successive departures is negligible, and state transitions occur at departure points. The transition probability matrix that describes the number of cells in the buffer after a departure can then be partitioned into submatrices, each of which is analogous to that of an M/D/1/K queue. These assumptions are reasonable for ATM traffic models in which the arrival rates are large and cell size is small. The accuracy of the analysis is evaluated, using a four-state MMPP model to represent the aggregate arrival process. The departure point and arrival point queue-length distributions, cell loss probabilities and average queuing delays are obtained analytically and compared to simulation results.>

The statistical characteristics of full-motion video sources using motion-adaptive variable-bit-rate coding techniques is studied. Analytical models are developed to describe the behavior of the coded video signals based on the encoder structure. The video-compression algorithm used is in compliance with the general MPEG syntax and bit-stream definition. Statistical characteristics associated with each block type and their aggregate are presented. A composite model to represent the number of bits per field for the encoded video traffic that comprises multiple autoregressive models for the number of blocks per field and the number of bits in each coded block is derived. The statistics measured from a sample video sequence are compared to those obtained by the model and it is observed that the model captures the coded video behavior for each block type and their combination reasonably well. This model can be used to further study the cell-generation process of full-motion video codecs and the aggregation of such video sources at the statistical multiplexers.>

A motion-adaptive variable-bit-rate (VBR) video codec is considered, and a motion-classified model is developed to represent the characteristics of various classes of motion activities, including scene changes. The codec switches between interframe, motion-compensated, and intraframe coding corresponding to low, medium, and high amounts of motion and scene changes, respectively. The model captures the motion of various video scenes by providing the statistics of VBR-coded video traffic through a first-order autoregressive process with time-varying parameters. The parameters of this model are obtained from a VBR-coded sample video sequence with the objective of matching the bit-rate distribution and the autocorrelation among the bit rates. The validity and accuracy of the model are evaluated, and the characteristics of aggregated traffic sources obtained with the model are discussed.>

The authors use a motion adaptive variable-bit-rate (VBR) video codec and propose a motion classified model to represent the characteristics of various classes of motion activities. The codec switches between interframe, motion compensated, and intraframe coding corresponding to low, medium, and high motions and scene changes, respectively. The model captures the motion of various video scenes and the codec structure by providing the statistics of VBR-coded video' traffic through a first-order composite autoregressive process with three motion classes. The parameters of this model are derived from a VBR-coded sample video sequence such that the bit rate distribution and the autocorrelation in bit rates of two successive frames are matched. The validity and accuracy of the model are verified. Using this model, the characteristics of aggregated traffic sources are discussed.>