A Downlink Transmission Method for OFDM Cellular Systems with Inter-Cell Interference Cancellation Using Simplified MLD based on MMSE QRD-M Algorithm

For next generation mobile radio communication, one-cell-frequency-reuse OFDM systems are attracting considerable attention. In such systems, it is necessary to improve the throughput performance of users at the cell-edge. This paper introduces an effective signal detection method with ICI canceller for OFDM cellular systems. The proposed method is an enhancement of a simplified MLD (Maximum Likelihood Detection) in which the signal path search space includes not only the desired signal space but also the interference signal space. This algorithm uses the MMSE QR decomposition of the virtual MIMO channel matrix and the M-algorithm in order to reduce the computational complexity of the original MLD. Its transmission performance is evaluated by computer simulation and it is confirmed that the signal detection that the proposed method can improve the throughput performance of the MS at the cell-edge in fully-loaded OFDM cellular systems. This paper also clarifies the tolerance of the frequency offset difference between local oscillators in the adjacent base stations for the proposed signal detection method.