A Hierarchical Selective CQI Feedback Scheme for 3GPP Long-Term Evolution System

In the 3GPP Long term Evolution system, one of the key techniques to meet the performance requirements in the downlink is the frequency selective schedule (FSS), in which resource allocation and modulation and code schemes are changed adaptively according to the downlink channel quality reported by user equipments (IE). Therefore, the channel quality information (CQI) scheme will directly affect the accuracy of the FSS and the system performance. In this paper, we propose a hierarchical selective (HS) CQI feedback scheme where a hierarchical structure is used to divide the whole system band into subbands and only CQI of the subbands with good channel quality is selected to be reported. The simulation results show that the proposed scheme can significantly reduce the CQI feedback overhead in the uplink by the cost of little performance degradation in the downlink.