High speed packet access with parallel interference cancellation and high-order modulation for coded FDD CDMA communications

The high-order modulation increases the transmission data rate, but apparently is more sensitive to amplitude and phase errors. For CDMA downlink transmissions, the common pilot channel reserves 10% of the total transmission power at base stations with the result of perfect channel estimation at mobile stations. Therefore the multiple access interference and co-channel interference can be successfully suppressed by parallel interference cancellation (PIC). Motivated by this, a high speed packet access (HSPA) scheme using PIC and flexible high-order modulation is proposed in this paper for frequency division duplex downlink CDMA communications. The proposed HSPA scheme has been evaluated by system level simulations in frequency selective Rayleigh fading channel with soft-decision channel decoding. The numerical results showed that the target coded bit error rate could be achieved by the HSPA receiver using 16-QAM with reasonable increase in signal-to-noise ratios, but the data rates can be doubled compared with the RAKE receiver using QPSK modulation