Iterative Suboptimal Maximum Likelihood Receiver for Nonlinearly Distorted SC-FDMA Symbols

Abstract

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.

Non-linear distortion noise cancellation for satellite return links

“…The output of this process are the improved received symbols after a number of iterations. The IMI cancellation approach has been adopted for systems with SC-FDMA in [9]. However, the same estimator for the interfering component based on a single scaling factor for all symbols is applied.…”

“…Cancellation of the IMI has been first proposed in [8] for OFDM systems. The approach has been adopted for systems with SC-FDMA in [9]. The interfering component is estimated by means of a model for the received constellation centroids based on the Bussgang decomposition [10], where the cross-correlation between the transmitted and received symbols is exploited, and a single cross-correlation factor is used for all the symbols in the constellation.…”

Iterative Cancellation of Non-Linear Distortion Noise in Digital Communication Systems

“…Finally, the buffer is released and a new set of received symbols is processed. The IMI cancellation approach has been studied for coded OFDMA signals in [8] and adopted for systems with SC-FDMA in [9], [10]. However, the same estimator for the interfering component based on a single scaling factor for all symbols from (2) is applied.…”

“…In TDMA, even though the SRRCF at the transmitter is matched to the one at the receiver, there is a residual nonlinear distortion for low roll-off-factors, due to the truncation of the filter impulse response to reduce the processing complexity and latency. The improved IMI cancellation receiver is tested against the state-of-the-art IMI cancellation receiver which is studied in [7]- [10] for OFDMA and SC-FDMA, referred to as standard receiver, where a single attenuation factor for the received symbols is used in the IMI cancellation procedure. In addition, the standard receiver is also tested in the case, where data pre-distortion is employed at the transmitter.…”

“…The approach has been adopted for SC-FDMA in [9], [10]. The interfering component is estimated by means of a model for the received constellation centroids based on the Bussgang decomposition [11], where the attenuation of the transmitted symbols in the channel is exploited.…”