Resource Allocation Algorithms for Multicast OFDM Scenarios Based on Subband-CQI Feedback

Multicast transmission is one of the key enablers towards a more efficient distribution of multimedia content in group-oriented services delivered in current and envisaged cellular networks. Traditionally, most multicast techniques adopt conservative strategies to choose the modulation and coding scheme (MCS) to deliver the service to all the multicast users. Unfortunately, these conservative strategies present two main drawbacks. Firstly, the multicast MCS is selected according to the propagation characteristics of the worst user in the multicast group, thus severely compromising spectral efficiency. Secondly, this MCS selection is done on the basis of wideband channel quality indicators (CQIs), and therefore neglects the frequency-selective character of the channel experienced by the different users. In trying to confront these two drawbacks, novel subband CQI-based schemes are proposed in this paper leading to improved spectral efficiencies while still fulfilling quality of service (QoS) metrics.