I/Q Imbalance Problem in SC-FDMA System with DCT and DFT Basis Functions

F S Al-Kamali,N A Odhah,Hefdhallah Sakran

doi:10.1155/2015/723805

Abstract

In-phase/quadrature-phase (I/Q) imbalance is one of the most serious concerns in the practical implementation of the direct conversion receiver architecture. This paper investigates and analyzes the impacts of the I/Q imbalance on the performance of the single-carrier frequency-division multiple access (SC-FDMA) system with different basis functions by computer simulations only. The suitable phase and amplitude of I and Q branches that can be utilized in SC-FDMA system are studied and determined through simulations for different I/Q imbalance scenarios and different subcarrier mapping schemes. Simulation results show that the phase and amplitude of I and Q branches have significant effects on the bit error rate (BER) performance of the SC-FDMA system.

Highlights

Due to high spectral efficiency and robustness against frequency-selective fading, orthogonal frequency-division multiple access (OFDMA) has been chosen as a downlink transmission technique in 3GPP long-term evaluation (LTE) standards [1]
The work in this paper is distinct from the previous research works in this area in that we study the effects of the in-phase and quadrature-phase (I/Q) imbalance problem using a three-dimensional results
The performance of the discrete Fourier transform (DFT)-Single-carrier frequencydivision multiple access (SC-FDMA) and the discrete cosine transform (DCT)-SC-FDMA systems in the presence of I/Q imbalance problem has been evaluated by simulations

Summary

Introduction

Due to high spectral efficiency and robustness against frequency-selective fading, orthogonal frequency-division multiple access (OFDMA) has been chosen as a downlink transmission technique in 3GPP long-term evaluation (LTE) standards [1]. Simulation results show that I/Q imbalance problem significantly degrades the system performance and its effects on the DCT-SC-FDMA system are greater than that on the DFT-SC-FDMA system.

Results

Conclusion