Design of a novel hybrid intercarrier interference mitigation technique through wavelet implication in an OFDM system

Orthogonal Frequency Division Mtfltiplexing (OFDM)is the most preferred and widely used multiplexing tech- nique in current wireless environment for sidelining the spectrum scarcity problem by splitting a signal into N signals and subsequently modulating them through several orthogonal subcarriers (which bears high frequency). With several great features,OFDM is severely affected by undesirable affects of frequency offset errors and Local Oscillator (LO)frequency synchronization errors.This paper proposes an approach that devises a new hybrid technique,which is a combination of Maximum Likelihood Estimation (MLE)and Self Cancellation (SC)techniques through wavelet implication,to enhance BER performance of the OFDM system.A comparative analysis of SC,MILE,and wavelet-based hybrid InterCarrier Interference (ICI)cancellation techniques was conducted using 64-QAM and differential offset (0.02 and 0.01)for differential data bits (4 Mb and 16 Mb)to justify the outstanding results.The simulation results showed a significant byte-error-rate improvement over different legacy techniques based on fast Fourier transform.

A novel energy-efficient ICI cancellation technique for bandwidth improvements through cyclic prefix reuse in an OFDM system

作为一项非常有前景的技术,正交频分复用(orthogonal frequency division multiplexing,OFDM)解决了频谱分配中的带宽不足问题,引领了无线移动通信领域的发展。然而,多普勒频移和本地振荡器频率同步误差的存在会导致载波间干扰(inter carrier interference,ICI),严重影响了正交频分复用。以往文献中提出了许多ICI消除技术,例如自消除法(self-cancellation,SC),最大似然估计法(maximum likelihood estimation,MLE)和加窗法,但需要在带宽冗余和系统复杂度之间权衡。本文基于接收端循环前缀(cyclic prefix,CP)再利用,提出了一种节能且具有有效带宽的新技术来消除ICI。自消除法和最大似然估计法在发送端发送整个OFDM符号数据时会产生冗余,而本文提出的技术仅使用循环前缀数据(仅占总符号带宽的20%)来估计信道,产生与前两者类似结果的同时节省了大量带宽。仿真结果表明,该技术在误差性能方面有显著的改进;并且在实现高带宽增益的同时,能效也得到了实质性的改善。因此,该技术优于传统ICI消除技术。