By design, IS-95 filter generates remaining ICI (interchip interference) after matched filtering in the receiver side. To keep the backward compatibility, IS-95 filter is recommended as a chip waveform shaping filter in all the sequels of international standard from the 3GPP2. The performance degradation by the filter was not significant in a conventional QPSK modulation scheme but not negligible in the recently proposed system where multi-level modulation scheme is adopted. In this paper, we investigate the performance degradation caused by this ICI of the IS-95 filter and propose MMSE receiver filter to compensate for the performance loss. We apply the proposed receiver to CDMA1xEV-DV system where multi-level modulation is used.

In this paper, we first analyze the performance loss due to the waveform shaping filter specified by the 3GPPZ. Analysis and simulation results show that there is significant SNR penalty which was not usually considered in the previous system. Then we propose the MMSE receiver filter which is designed to eliminate remaining interference and satisfy the FCC mask rule at the same time. Both the analysis and simulation results show that most of the SNR penalty can be eliminated.