Effective CQI feedback mechanism for adaptive multicast IPTV in wireless cellular networks

Conventional multicast IPTV services in wireless cellular networks use the most robust modulation and coding scheme (MCS) to guarantee that all mobile users within the cell can receive the video streams with acceptable qualities. Since the most robust MCS has the lowest data rate, the spectral efficiency is not good. To enhance the spectral efficiency, the adaptive multicast IPTV that uses the adaptive MCS based on signal-to-noise ratios (SNRs) or channel quality indicators (CQIs) of user equipments (UEs) was proposed. However, the CQI feedback messages induced by the adaptive multicast scheme incur additional signaling overhead. To effectively reduce the amount of CQI feedback messages, this paper1 presents a novel CQI feedback scheme. Numerical results show that the proposed feedback mechanism can significantly reduce the amount of CQI feedback messages and thus the load at the base station.