Baseband receiver design for 3GPP Long Term Evolution downlink OFDMA systems under fast-fading channels

This paper presents baseband receiver design for the third Generation Partnership Project (3GPP) Long Term Evolution (LTE) downlink systems under fast-fading channels. We aim to support 2×2 open-loop spatial multiplexing at high mobility up to 240 Km/hr with well-synchronized capability. The proposed receiver contains the functional blocks of mode detection, synchronization, channel tracking, inter-carrier interference (ICI) cancellation and iterative MIMO detection. When the receiver starts up, a blind mode detection algorithm is designed to distinguish the length of cyclic prefix. The proposed estimation method for the residual carrier frequency offset and sampling clock offset can exploit the information carried in the scattered reference signals compared to the conventional approaches and thus better mean squared estimation error can be obtained. The iterative inter-antenna interference (IAI) plus ICI cancellation scheme improves the performance of MIMO detection under high mobility. As a result, the receiver has good performance even with constellation of 64-QAM under the mobility of 240 Km/hr.