Implementation of Pilot Channel Estimation Techniques for OFDM System with Low Mean Square Error

Abstract

Abstract: Orthogonal Frequency Division Multiplexing
(OFDM) has grown to be the most popular multi carrier
communication system in high speed data communications.
The available bandwidth is utilized efficiently, and more data
rates can be achieved because of orthogonal carriers in OFDM
system. OFDM system requires precise channel estimation and
synchronization to reduce Mean Square Error (MSE). In this
work, various Pilot Channel Estimation (PCE) techniques are
used to compute CSI (Channel State Information). Pilots are
transmitted along with the data and channel response is
computed with various interpolation techniques such as linear,
spline, cubic Interpolation techniques by extracting the pilots
at the receiver. The performance metrics like Mean Square
Error (MSE) and computation time are computed and
compared for different PCE techniques. Discrete Fourier
Transform (DFT) based channel Estimation is combined with
interpolation techniques and channel response is computed and
compared with Least Squares (LS) and Minimum Mean
Square Error (MMSE) approaches. LS, MMSE, LMMSE
(Linear MMSE) methods are combined with Time
Division(TD) and Time Division Duplexing(TDD) techniques
to compute MSE. TD-LMMSE approach achieves least MSE
with more computation time.

Index Terms: OFDM, channel estimation, interpolation, CSI,
MSE, computation time.