A New Channel Estimation Method Based on Per-path Interference Cancellation for Cdma Downlink System

摘要

Since the auto-correlation of the Training Sequence (TS) is not perfect and the Channel Impulse Response (CIR) estimated by this TS will exists the inter-path interference at User Equipments (UE). If there is only one user at this slot, then there only exists the intra-user interference, such as GSM/EDGE system. If there is more than one user at this slot, then there exist the intra- and inter-user/cell interference, such as TD-SCDMA, CDMA2000, WCDMA systems. To mitigate this kind of interference, interference cancellation based on chip level methods are conventionally adopted, whose complexity is very high. To overcome the complexity problem in previous method, a lower complexity method named Per-Path Interference Cancellation (PPIC) has been proposed. Meanwhile, this method also has much higher estimation accuracy but its iteration time is very lager in some scenario, such as stronger interference or low SNR. In this study, a new iteration method based on per-path interference cancelation has been proposed. Take TD-SCDMA system for example, the simulation results show that the proposed method only needs less iteration times and obtains better estimation accuracy compared with the PPIC method.