Performance Analysis of ICA Based Carrier Frequency offset Estimation for Multiband OFDM based UMB Systems

Abstract

Orthogonal frequency division multiplexing (OFDM) is a well known method for high data rate wireless transmission. Multiband-OFDM (MB-OFDM) is one of the capable technique for PHY layer of short-range high data-rate UWB communications. It combines Orthogonal Frequency Division Multiplexing (OFDM) with a multi-band approach enabling UWB transmission to inherit all the strength of OFDM technique which has already been proven for wireless communications. The multibanding introduces orthogonality in the frequency domain and longer impulse radio pulses in every band. The Multi-Band OFDM (MB-OFDM) system divides the Ultra Wide Band (UWB) spectrum (3.1-10.6 GHz) into 528 MHz wide sub-bands and uses OFDM modulation to transmit the information in each sub-band. newlineThe UWB provide channel models for short range by modifying Saleh-Valenzula(S-V) channel Model. It provides different channel models for both Line-of-Sight (LOS) and Non-line-of- Sight (NLOS) environment conditions of both indoor and outdoor conditions. Although OFDM is resistant to multipath fading, it requires a high degree of synchronisation to maintain sub-carrier orthogonality. Therefore the level of performance of the system depends first on the accuracy in estimating the carrier frequency offset. newlineCarrier frequency offset (CFO) severely deteriorates the performance of OFDM receiver. Here an effective time domain CFO estimation and compensation method using independent component analysis (ICA) for multiband orthogonal frequency division multiplexing (MBOFDM) based ultra-wideband system is proposed for different channel models considering low data rate ,medium data rate and high data rate. The channel models CM1, CM2, CM3 and CM4 were simulated for QPSK and 16QAM modulation techniques. A data supported CFO estimation technique, which is robust to a larger offset, is presented as a novel method in compensation of CFO. An effective separation matrix scheme of OFDM signal with CFO is obtained.