Downlink Transmission in Multi-Carrier Systems with Reduced Feedback

in this paper we address the problem of reducing the feedback for the downlink transmission in multi-carrier systems. In these systems multiple Component Carriers (CCs) are aggregated together to form a wide spectrum. Consequently, a large feedback overhead is required to report the channel quality information over such a wide bandwidth. We first generalize two existing feedback reduction techniques, and then propose a new one. These techniques use different feedback schemes across the CCs, or allow some CCs to be un-reported, for the purpose of reducing the amount of feedback. Performance for the investigated techniques is evaluated in a realistic system setting with different traffic conditions and terminal categories. Based on the obtained results, the selection of proper feedback reduction technique under different load conditions can be made. The findings are useful for reducing the feedback overhead in future generation wireless communication systems that operate over multiple CCs.