Design and Analysis of CQI Feedback Reduction Mechanism for Adaptive Multicast IPTV in Wireless Cellular Networks

To guarantee that all mobile users in a cell can watch video with acceptable quality, conventional multicast IPTV services use the most robust modulation and coding scheme (MCS) for video transmission, resulting in worse spectral efficiency. To enhance the spectral efficiency, the adaptive multicast IPTV using the adaptive MCS based on signal-to-noise ratios (SNRs) or channel quality indicators (CQIs) was proposed in the literature. However, the CQI feedback messages induced by the adaptive multicast IPTV incur additional signaling overhead. Thus, a novel CQI feedback scheme was proposed in this paper to effectively decrease the amount of CQI feedback messages while preserving the system performance. Additionally, the CQI feedback rates of various CQI feedback schemes were theoretically analyzed based on the multi-dimensional Markovian model. Numerical results show that the proposed CQI feedback mechanism significantly reduces the CQI feedback rate without sacrificing the system performance and outperforms other existing CQI feedback schemes. Moreover, the analytical results almost coincide with simulation results, demonstrating that the theoretic analyses are accurate.