Amplifier nonlinearities affect drastically the performance of Orthogonal Frequency Domain Multiplexing OFDM systems. In this paper, the effects of amplifier nonlinearities is evaluated in OFDM with Space-Division-Multiple-Access (SDMA). We showed that nonlinear power amplifier reduced dramatically the performance of multiple-antennas OFDM systems.

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Design of Weyl-Heisenberg sets of waveforms for robust orthogonal frequency division multiplexing (OFDM) has been the subject of a considerable volume of work. In this paper, a complete parameterization of orthogonal Weyl-Heisenberg sets and their corresponding biorthogonal sets is given. Several examples of Weyl-Heisenberg sets designed using this parameterization are presented, which in simul...

Channel estimation is one of the most significant technologies in orthogonal-frequency-divisionmultiplexing(OFDM) . Inter-carrier-interference (ICI) occurs in OFDM which must be removed. There are various methods to reduce ICI in OFDM . Channel estimation techniques are used to investigate to reduce ICI in OFDM .In this paper we will discuss Channel estimation methods and DFT based channel esti...

We proposed a novel rate-1, space-frequency (SF) code for an Orthogonal Frequencey Division Multiplexing (OFDM) system with transmit (M ) and receive (N ) antennas that achieves the maximum diversity attainable over frequencyselective channels. Since the SF code symbol is transmitted in one OFDM block duration, it has smaller processing delay than previously proposed Space-Time-Frequency (STF) ...

Increased data rates and reliability are the two key factors required to support emerging multimedia applications and new communications technologies. The two techniques used in high data rate transmission are orthogonal frequency division multiplexing (OFDM) and multiple-input multiple-output (MIMO) scheme. The OFDM is used to mitigate the problem of inter symbol interference (ISI) and provide...

This paper presents a new ground penetrating radar (GPR) design approach using orthogonal frequency division multiplexing (OFDM) and compressive sensing (CS) algorithms. OFDM technique is applied to leverage GPR operating speed with multiple frequency tones transmission and receiving concurrently, and CS technique allows utilizing reduced frequency tones without compromising data reconstruction...

The performance comparison of the most feasible multiple access techniques proposed for fourth generation wireless communication systems, i.e., Orthogonal Frequency Division Multiplexing (OFDM) and Multi-Carrier Code Division Multiple Access (MC-CDMA) is evaluated. The objective is to find the most suitable technique for implementation in 4G Communication Systems. The modems of OFDM and MC-CDMA...

This paper will focus on improving the performance of orthogonal frequency division multiplexing (OFDM) in Rayleigh fading environments. The proposed technique will use a previously published method that has been shown to improve OFDM performance in independent fading, based on ordered sub-carrier selection. Then, a simple non-iterative method for finding the optimal bit-loading allocation was ...