The demand for increased channel capacity in mobile and wireless communication has been rapidly increasing due to multi fold increase in demands of multimedia services and mobile data. In the present scenario, high data rate are offered by WLAN, WiMax and LTE/ LTE-Advanced (LTE-A). Developing a wireless system for more spectral efficiency under varying channel condition is a key challenge to pr...

Multiprocessor platforms have been proposed as an enabling technology for Cognitive Radio. In this paper, we explore various FFT implementations on a multiprocessor prototype platform as building components for OFDM based Cognitive Radio. The results show that our FFT implementations on the multiprocessor platform are fast and energy efficient. Moreover, the FFT implementations can be dynamical...

This work presents a study of the Fractional Fourier Transform (FrFT) modulation scheme for Multiple Input Multiple Output (MIMO) multicarrier systems. Two forms of FrFT modulation techniques were observed; one involved the FrFT-OFDM implementation style with cyclic prefix, while the other precludes the FrFT following some established logical signal processing justifications. Then, both were co...

Conventional OFDM employs a guard interval to combat delay spread distortion oftransmitted data. This reduces the efliciency of the OFDM transmission. The combined OFDM-Equalization strategy described here employs an Adaptive Equalizer to combat delay spread distortion and thereby facilitates the use of very short guard intervals and thus a more eflcient OFDM modulation scheme. The OFDM receive...

A special pilot pattern across two OFDM symbols is devised for channel estimation in OFDM systems with IQ imbalance at receiver. Based on this pilot pattern, a high-efficiency time-domain (TD) least square (LS) channel estimator is proposed to suppress channel noise by a factor of N/(L+1) in comparison with the frequency-domain LS one in [1] where N and L+1 are the total number of subcarriers a...

This paper proposes that several FFT algorithms such as radix2, radix-4 and split radix were designed using VHDL with the multiplication complexity reduced more than 30% by using the newly proposed CSD constant multipliers instead of the programmable multipliers and the simulations of standard 0.35 μm. The sizes of FFT/IFFT operations are varied in different applications of OFDM systems. The re...

Integrated circuits to support digital communication standards are commonly based on a Fast Fourier Transform (FFT) of some length. Flexible length makes the design more usable for configurable algorithm-specific circuits. The proposed project discusses the functional aspects of a FFT design. As the transform length increases the amount of arithmetic involved becomes excessive. This makes Fast ...

Orthogonal Frequency Division Multiplexing (OFDM) is multiplexing technology of orthogonal multicarrier, and the channel estimation model based on pilot in OFDM systems is analyzed; Now that, the channel estimation based on pilot needs interpolation, in order to reduce the complexity of the interpolation algorithm, the FFT channel estimation algorithm based on pilot is studied. Because of the d...

Recently, the demand of high-speed network in home is increasing. PLC (Power Line Communication) is expected as one method of realizing it. OFDM is one of the methods, which realizes high-speed PLC. But the minimum stopband attenuation of OFDM modulation is only -13dB. It indicates that OFDM subchannels are not spectrally isolated, therefore OFDM is sensitive to the locations of narrow band int...

Orthogonal frequency division multiplexing (OFDM) is a special case of multicarrier transmission, where a single data stream is transmitted over a number of lower ratesubcarriers.4G and other wireless systems are currently hot topics of research and development in the communication field. Orthogonal frequency division multiplexing (OFDM) is the most commonly used modulation scheme for high data...