A cell specific reference signal interference cancellation scheme for LTE cellular access systems

Heterogeneous network is supported to improve the link performance in LTE Rel. 10+. The network introduces co-existence of Macro and Pico cell which can alleviate the potential traffic congestion caused by increased user density. Along with the co-existence of difference cells comes the disadvantage of inter-cell interference. Although almost blank subframe (ABS) is proposed to mitigate the interference, the reference signal in ABS still inevitably causes interference. This paper focuses on the interference cancellation by utilizing the information in the ABS. First, the interference signal model which takes account of channel effect, time and frequency error is presented. Based on this model, interference cancellation scheme is studied. The timing and carrier frequency offset of interference signal is compensated. Afterwards, the reference signal of interfering cell is generated locally and channel response is estimated by making use of channel statistics. Then, the interference signal is reconstructed based on previous estimate of channel, timing and carrier frequency offset. The interference is then mitigated by substracting the estimate of interference signal. Computer simulation shows this interference cancellation algorithm significantly improves performance in different channel conditions.