Mobile OFDM refers to OFDM systems with fast moving transceivers, in contrast to traditional OFDM systems whose transceivers are stationary or have a low velocity. In this paper, we use the basis expansion model (BEM) to model time-varying OFDM channels. Using different BEM’s, we investigate various architectures to implement the least-squares (LS) channel estimation and its corresponding zero-...

Parallel combinatory orthogonal frequency division multiplexing (PC-OFDM) yields lower maximum peak-toaverage power ratio (PAR), higher bandwidth efficiency and lower bit error rate probability (BER) on Gaussian channels compared to OFDM systems. However, PC-OFDM does not improve the statistics of PAR significantly. In this paper, the use of a set of fixed permutations to improve the statistics...

OFDM/OQAM is a special type of multi-carrier modulation that can be considered as an alternative to conventional OFDM with cyclic prefix (CP) for transmission over multipath fading channels. Indeed, as it requires no guard interval, it has the advantage of a theoretically higher spectral efficiency. Furthermore if the pulse shape is well-localized in frequency, the resulting OFDM/OQAM signal sa...

Orthogonal frequency division multiplexing (OFDM) has been attracting much attention because of its robustness against frequency selective fading. Instead of well-known cyclic prefix (CP) insertion, known training sequence (TS) insertion can be used for OFDM block transmission (called TS-OFDM). In this paper, we propose a new receiver design, which can obtain the frequency diversity gain throug...

The 60 GHz band is of much interest since this is the band in which a massive amount of spectral space (5 GHz) has been allocated unlicensed worldwide for dense wireless local communications. OFDM has gained much popularity in the field of wireless communication because of its ability to transfer the data at higher rate, high bandwidth efficiency and its robustness with regard to multipath and ...

1Professor,Dept.of ECE,GMR Institute of Technology,Rajam,AP,India 2Professor, Dept.of ECE ,GMR Institute of Technology,Rajam, AP,India 3Assistant Professor, Dept.of ECE ,GMR Institute of Technology,Rajam, AP,India ---------------------------------------------------------------------***--------------------------------------------------------------------Abstract Orthogonal Frequency Division Mult...

Orthogonal frequency division multiplexing (OFDM) is an attractive, promising and emerging technique which achieves high data rate in mobile multipath channels. LTE was the first technology to use OFDM. There are many more advantages of OFDM which includes immunity to multipath fading. High Peak to Average Power Ratio(PAPR) is the main disadvantage of OFDM-LTE Networks. This paper describes how...

In this letter, we propose layered asymmetrically clipped optical-orthogonal frequency-division multiplexing (LACO-OFDM) with index modulation (IM), i.e., LACO-OFDM-IM for optical wireless systems. classical LACO-OFDM, the spectral leakage because of out-of-band clipping harmonics increases baseband bandwidth (BB) resulting in lower efficiencies. For LACO-OFDM-IM, use IM and optimize BB by filt...

Being sensitive to synchronization errors, symbol timing is a key factor affecting the performance of orthogonal frequency division multiplexing (OFDM) -based visible light communication (VLC) systems. A novel method based on odd-even symmetry for direct current biased optical OFDM (DCO-OFDM) investigated in this paper. The proposed produces an excellent pulse-like metric, resulting sharper pea...

To improve performance of orthogonal frequency division multiplexing (OFDM) for fading channels, linear dispersion coded OFDM (LDC-OFDM) was recently proposed to increase frequency and time diversity with high bandwith efficiency and performance. The performance of recently proposed LDC-OFDM was investigated through simulations. This paper analyzes the diversity aspects of LDCOFDM system, and s...