Analysis and Design of Channel Estimation in Multicell Multiuser MIMO OFDM Systems

Peng Xu Peng Xu,Jinkuan Wang Jinkuan Wang,Feng Qi Feng Qi,Jiangzhou Wang Jiangzhou Wang

doi:10.1109/tvt.2014.2322654

Peng Xu Peng Xu, Jinkuan Wang Jinkuan Wang + Show 2 more

Open Access

https://doi.org/10.1109/tvt.2014.2322654

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Abstract

This paper investigates the uplink transmission in multicell multiuser multiple-input multiple-output (MIMO) orthogonal frequency-division multiplexing (OFDM) systems. The system model considers imperfect channel estimation, pilot contamination (PC), and multicarrier and multipath channels. Analytical expressions are first presented on the mean square error (MSE) of two classical channel estimation algorithms [i.e., least squares (LS) and minimum mean square error (MMSE)] in the presence of PC. Then, a simple H-infinity (H-inf) channel estimation approach is proposed to have good suppression to PC. This approach exploits the space-alternating generalized expectation-maximization (SAGE) iterative process to decompose the multicell multiuser MIMO (MU-MIMO) problem into a series of single-cell single-user single-input single-output (SISO) problems, which reduces the complexity significantly. According to the analytic results given herein, increasing the number of pilot subcarriers cannot mitigate PC, and a clue for suppressing PC is obtained. It is shown from the results that the H-inf has better suppression capability to PC than classical estimation algorithms. Its performance is close to that of the optimal MMSE as the length of channel impulse response (CIR) is increased. By using the SAGE process, the performance of the H-inf does not degrade when the number of antennas is large at the base station (BS).

Highlights

F UTURE wireless communications require the outstanding capability to combat multipath fading and to offer high spectral efficiency
We have shown that the minimum mean square error (MMSE) algorithm can obtain optimal performance by using prior information and better suppression to pilot contamination (PC)
We consider a multicell MU-multiple-input multiple-output (MIMO) system with M antennas at each base station (BS) to investigate the impact of PC on the mean square error (MSE) of channel estimation algorithms

Summary

Introduction

F UTURE wireless communications require the outstanding capability to combat multipath fading and to offer high spectral efficiency. Multiple-input multiple-output (MIMO) combined with orthogonal frequency-division multiplexing (OFDM) has been widely considered to be a promising candidate [1], [2]. Manuscript received July 18, 2013; revised December 13, 2013 and February 14, 2014; accepted April 10, 2014. Date of publication May 8, 2014; date of current version February 9, 2015. The review of this paper was coordinated by Prof.

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