Power Aware Ofdm Lte System Architecture for Mu-Mimo

Abstract

This project proposes the performance of two suboptimal channel estimation algorithms, denoted as RB and RBG, to be employed in a downlink MUMIMO communication between a BS and multiple MSs. Communications are compliant with the LTE standard in FDD mode and are based on OFDM modulation. Since the LTE standard defines a fundamental block, denoted as PRB, consisting of a given number of consecutive subcarriers in a time slot, the key idea is to approximate the channel as constant over multiples of this unit. This leads to a significant saving in terms of size of the feedback to be transmitted to the BS for precoding purposes, with minimal (often negligible) BER performance loss in all the considered scenarios.  The LTE standard uses three different modulation schemes to adapt to various channel conditions in order to improve achievable data rates. These modulation schemes are the QPSK, 16-QAM and 64-QAM. This paper presents an overview of an LTE digital communication system. A Simulation model, designed in order to study the effects of the different modulation schemes on the basis of BER performance with an AWGN channel model. Different subsystems within the transmitter and receiver blocks are implemented in MATLAB. It is noted that the LTE system uses different coding techniques to offer reliable and secure services to the users. Depending on the assumed channel condition (clear, medium clear or noisy), the 64- QAM, 16-QAM or QPSK modulation scheme, on the transmitter side as well as the corresponding demodulation scheme, on the receiver side is used. Based on the recovered data bits, the obtained bit error rates are analyzed, compared and discussed.