On performance of cooperative network based on OFDM combined with TDM using MMSE-FDC in the presence of nonlinear HPA

Amir Ligata,Fumiyuki Adachi,Haris Gacanin

doi:10.1186/1687-1499-2013-185

Amir Ligata, Fumiyuki Adachi + Show 1 more

Open Access

https://doi.org/10.1186/1687-1499-2013-185

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Abstract

In this paper, we analyze the impact of nonlinear high-power amplifier (HPA) on the performance of cooperative network based on orthogonal frequency division multiplexing combined with time-division multiplexing (OFDM/TDM) using minimum mean-square-error frequency-domain combining (MMSE-FDC) in a frequency-selective fading channel. We design a novel MMSE-FDC weights while taking into account the nonlinearity of HPA at source and relay. Closed-form symbol error rate and outage probability expressions are derived while approximating the residual inter-slot interference after the MMSE-FDC as a random Gaussian variable. We discuss and address the nonlinear OFDM/TDM system design issues in cooperative network using the obtained simulation and theoretical results. We show that the OFDM/TDM with MMSE-FDC can be used to reduce the impact of nonlinear HPA on overall performance of cooperative network in comparison to OFDM while providing the target quality-of-service for reduced required signal-to-noise ratio. This is because OFDM/TDM with MMSE-FDC achieves frequency diversity in addition to cooperative diversity, while reduced peak-to-average power ratio makes it more robust on nonlinear degradation due to HPA saturation in comparison to conventional OFDM.

Highlights

Multi-antenna techniques are promising candidates to achieve broadband data services in a limited available bandwidth
4.1.1 Ideal high-power amplifier (HPA) The performance of cooperative network based on orthogonal frequency division multiplexing (OFDM)/TDM with MMSE-FDC is largely dependent on channel frequency selectivity; we investigate the effect of different propagation scenarios
5 Conclusion In this paper, we investigate the impact of nonlinear HPA using AF-instantaneous power scaling (IPS) at relay on the performance of cooperative OFDM/TDM with MMSE-FDC in the frequencyselective fading channel

Summary

Introduction

Multi-antenna techniques are promising candidates to achieve broadband data services in a limited available bandwidth. The cooperative network using OFDM/TDM access based on MMSE frequency-domain combining (MMSEFDC) in a frequency-selective fading channel may be an attractive solution to achieve both cooperative and frequency diversity gains with a lower PAPR in comparison with cooperative OFDM [21]. The PAPR is not completely eliminated and the nonlinear HPA may considerably degrade the performance of cooperative network based on OFDM/TDM with MMSE-FDC. Unlike [21], in this work, we present extensive analysis of cooperative network based on OFDM/TDM with MMSE-FDC in frequency-selective fading channel in respect to impact of nonlinear HPA. We discuss and address the nonlinear OFDM/TDM design issue and show that cooperative network based on OFDM/TDM with MMSE-FDC can be used to improve the robustness against nonlinear degradation due to HPA saturation in comparison to conventional OFDM. The remainder of this paper is organized as follows: section 2 presents the network model; performance analysis is provided in section 3, while numerical results and discussions are presented in section 4; and section 5 concludes the paper

Transmit signal representation

Outage probability

Findings

Conclusion