MIMO-OFDM Channel Estimation Using Pilot Carries

Abstract

A multiple-input multiple-output (MIMO) communication system combined with the orthogonal frequency division multiplexing (OFDM) modulation technique can achieve reliable high data rate transmission over broadband wireless channels. Channel state information for both single-input single-output (SISO) and MIMO systems based on pilot aided arrangement is investigated in this paper. The estimation of channel at pilot frequencies with conventional Least Square (LS) and Minimum Mean Square (MMSE) estimation algorithms is carried out through Matlab simulation. The performance of MIMO OFDM and SISO OFDM are evaluated on the basis of Bit Error Rate (BER) and Mean Square Error (MSE) level. Further enhancement of performance can be achieved through maximum diversity Space Time Block Coding (STBC) and Maximum Likelihood Detection at transmission and reception ends respectively. MMSE estimation has been shown to perform much better than LS but is more complex than LS for the MIMO system using pilot carriers.

OFDM-System Design Using Adaptive Modulation and Channel Estimation for Underwater Acoustic Communication

“…In this experiment we insert the pilot symbols of length 4 for each frame in the transmitter side and after FFT algorithm we remove the pilot symbols at the receiver side. The capability to generate and to demodulate the signal with the use of FFT algorithm is one of the main factors for OFDM to become popular in transmission schemes [13]. By using IFFT/FFT techniques, implementation of modulation and demodulation is computationally efficient.…”

“…The Kalman filter is then applied to estimate the unknown state of the system. Received signal y k (n) at each instant is given as input observation to Kalman filter algorithm [13] and the following figure (2) shows the Kalman filter algorithm. There is a consideration of two ideal equations: Time Update and Measurement Update and both set of e equations are applied at each k th state.…”

Performance Analysis of MIMO OFDM System by using LS and MMSE Techniques

“…The binary input data is first modulated different modulation technique such as QPSK, BPSK, depending upon the channel like fading channel, IEEE 802.11.After this coding is done. The serial data is fed to serial to parallel converter [12,13]. This reduce data rate by N times, where N is number of parallel stream.…”

Enhanced Adaptive Channel Estimation Technique for MIMO-OFDM Wireless Systems

“…Training based requires pilot bits to be sent along with the data. Arrangement of pilot bits can be block type and comb type [7]. In block type transmission of pilot is done on each and every subcarrier at successive intervals of time.…”

“…While in comb type pilots are sent for whole time i.e pilots are implanted into apiece OFDM emblem. Blind channel approximation is done by exploiting the statistical [7] properties of the network. It is advantageous to use as it does not wastes bandwidth as no pilots are needed.…”