Power Allocation between Pilot and Data Symbols for MIMO Systems with MMSE Detection under MMSE Channel Estimation

Jun Wang,Hongyang Chen,Shaoqian Li,Oliveryu Wen

doi:10.1155/2011/785437

Abstract

For multiple-input multiple-output (MIMO) wireless communication system with minimum mean square error (MMSE) detection, a new scheme of power allocation between pilot and data symbols is investigated under MMSE channel estimation in this paper. First, we propose a novel soft-output MMSE MIMO detector by taking into consideration the channel estimation error. Then, through the application of randommatrix theorem, we propose an efficient scheme for power allocation between pilot and data symbols which maximizes the lower bound of postprocessing signal-to-interference-and-noise ratio (SINR) for MIMO systems with equal number of transmitter and receiver antennas. We have proven the existence and uniqueness of the proposed optimal power allocation settings. Furthermore, our analysis shows that the proposed power allocation is also valid and applicable for those MIMO systems with unequal number of transmitter and receiver antennas. Finally, our extensive simulation results have validated this novel power allocation scheme.

Highlights

For wireless multiple-input multiple-output (MIMO) communication systems, most of the popular MIMO channel estimation approaches are based on maximum likelihood (ML) or minimum mean square error (MMSE) criteria while employing pilot symbols [1,2,3,4]
Soft-output linear minimum mean square error (MMSE) detection is widely applied in practical systems, because it has relatively lower, and manageable complexity while suppressing both coantenna interference (CAI) and noise at the same time [6]
M-PSK and 16-QAM modulations with Gray mapping are used in the simulations, and the simulations are performed for the MIMO systems with MR = 4 and MT = 2, 3, 4

Summary

Introduction

For wireless multiple-input multiple-output (MIMO) communication systems, most of the popular MIMO channel estimation approaches are based on maximum likelihood (ML) or minimum mean square error (MMSE) criteria while employing pilot symbols [1,2,3,4]. As the estimated MIMO channel matrix is inevitably imperfect, the channel estimation error should be taken into account while designing MIMO detectors in order to achieve better performances. This design philosophy has been investigated in [4] for ML detector and in [5] for V-BLAST detector. Its LLR generation needs to be modified to take the imperfect channel estimation into consideration in order to achieve better performances as in single antenna systems [7]. We propose a novel soft-output MMSE MIMO detector with this consideration

Objectives

Results

Conclusion