Iterative suboptimal maximum likelihood receiver for Nonlinearly distorted SC-FDMA symbols

Single Carrier Frequency Division Multiple Access (SC-FDMA) is the modulation scheme being employed in the uplink of Long Term Evolution (LTE) and will also be employed in the upcoming fourth generation (4G) system LTE Advanced. The main advantage of using SC-FDMA in the uplink in opposite to the traditional orthogonal frequency division multiple access (OFDM) is its lower sensitivity to nonlinear amplification. Nevertheless, the strict requirements of 4G systems suggest that techniques to reduce sensitivity even further should be introduced. In this paper, we evaluate the effect of nonlinearities in SC-FDMA and present an iterative receiver scheme to reduce the error probability of SC-FDMA systems undergoing nonlinear amplification. The technique consists in successive estimation and compensation of both the nonlinear distortion and the non-constant attenuation and rotation introduced by the transmitter high power amplifier (HPA). Simulation results expressed by the bit error rate (BER), the error vector magnitude (EVM) and the total degradation (TD) show that the proposed iterative receiver provides a significant performance improvement.