Efficient real-time video transmission in OVSF-CDMA system

The paper studies downlink channel utilization for real-time video traffic transmission in an orthogonal variable spreading factor code division multiple access (OVSF-CDMA) system. By modeling video traffic as a Markov modulated process and properly partitioning the states of the Markov process, an adaptive rate allocation scheme is proposed for real-time video transmission with quality of service (QoS) satisfaction while achieving high channel utilization. The scheme is applicable for packet switching and frame-by-frame real-time video transmission, and incorporates both physical layer and network layer characteristics. The QoS requirements include stringent packet delay and packet loss rate. Analytical and simulation results demonstrate that the proposed scheme can significantly improve the channel utilization over the commonly used effective bandwidth approach.