In this modern wireless technology Multicarrier communication is one of the more suitable and reliable communication technique. Orthogonal Frequency Division Multiplexing (OFDM) is used as modulation technique in multicarrier communication. The present paper gives an overview of OFDM and the various Channel Estimation techniques used in OFDM. The results implemented in MATLAB gives the performa...

Unique word OFDM is a novel technique for constructing OFDM symbols, that has many advantages over cyclic prefix OFDM. In this paper we investigate two different approaches for the generation of an OFDM symbol containing a unique word in its time domain representation. The two-step and the direct approach seem very similar at first sight, but actually produce completely different OFDM symbols. ...

In wireless communications systems, Orthogonal Frequency Division Multiplexing (OFDM) and Multiple Input Multiple Output (MIMO) are used to improve spectral efficiency and spatial diversity. Beamforming is used to improve bandwidth utilization. It increases the network range in wireless systems. The main challenge of OFDM system is Carrier frequency offset (CFO). The project focuses on CFO esti...

ABSTRACT Standard OFDM systems are associated with a rectangular grid in the time-frequency plane. However such a setup is in general not optimal for pulse shaping OFDM systems for doubly dispersive channels. We introduce lattice-OFDM systems (LOFDM), which are OFDM systems constructed with respect to general lattices in the time-frequency plane. We show how to design optimal pulse shapes for L...

This paper provide MMSE Channel estimation For MIMO-OFDM Using Spatial and Temporal Correlations. Generally there are a lot of methods for channel estimation of OFDM as well as MIMO OFDM. In this paper I first described about the latest MIMO OFDM channel estimation which is super resolution approach that explores spatial and temporal correlation of MIMO-OFDM. I then implemented it using MMSE ch...

In recent years, the wireless industry has shown great interest in OFDM systems. Indeed, such systems have been adopted in a variety of wireless applications such as digital audio broadcasting (DAB) and digital video broadcasting (DVB). Moreover, OFDM has also been proposed for indoor wireless networks and fixed wireless broadband access [1,2]. This growing interest was due to the realisation t...

This paper demonstrates the advantage of application time domain diversity combining (TDDC) at transmitter over receiver (TDDR) for a single layer ACO-OFDM in terms reduced complexity. The further implementation delay-and-advanced operation with TDDC two-layered LACO-OFDM system, where all subcarriers are utilized and an improved BER performance is achieved. new 2-LACO-OFDM system achieves 2.7 ...

In this paper, analytic expressions of upper bounds of the bit error probability provided by the MMSE receiver are derived for OFDM based systems when the number of carriers is large enough. Considering convolutive Forward Error Correcting schemes and QPSK constellations, it is shown that coded Linear Precoded OFDM (LP-OFDM) outperforms Coded OFDM (COFDM) if the input SNR is greater than a thre...

Low-density parity-check (LDPC) coded orthogonal-frequency-division multiplexing (OFDM) is studied as an efficient coded modulation technique suitable for fiber-optics communication systems. We show that in long-haul fiber optics communications LDPC-coded OFDM increases spectral efficiency and requires simple equalization to deal with chromatic dispersion. LDPC-coded OFDM is also a promising po...

Orthogonal frequency division multiplexing (OFDM) combined with time division multiplexing (TDM), called OFDM/TDM, can overcome the high peak-to-average-power ratio (PAPR) problem of the conventional OFDM. Its bit error rate (BER) performance in a frequency-selective fading channel is improved by adoption of frequency-domain equalization (FDE) based on minimum mean square error (MMSE) criterion...