Successive interference canceller with residual interference reduction for M2M wireless access system

This paper proposes two residual interference reduction schemes for the successive interference canceller (SIC) in M2M wireless access systems. In general, it´s difficult for SIC to completely eliminate interference due to channel estimation errors. Such errors are a serious problem if there are many terminals and the environment is multi-path. The first scheme, the Pre-FDE scheme, employs frequency domain pre-equalization (Pre-FDE) at the terminal side to alleviate the effect of multi-path propagation; it allows the base station to estimate the channel state information (CSI) precisely and also to reduce the residual interference. In the second scheme, the Path-SIC scheme, the base station estimates the CSI accurately by dealing with the interference replica of one path, not one terminal in one subtraction. Both schemes are simulated using actual temporal channel variations obtained by experiments. The simulation results show that the Pre-FDE scheme and the Path-SIC scheme improve the number of terminals transmitting simultaneously from 6 to over 10 compared with the conventional one. However, the PER performance of the Pre-FDE scheme degrades as the environmental speed increases.