Analog representation and digital implementation of OFDM systems
نویسندگان
چکیده
Many existing results on the analysis of OFDM systems are based on an analog representation. The actual implementation of OFDM transmitters typically consists of a discrete DFT matrix and a digital-to-analog (DAC) converter. In this paper, we show that the analog representation admits the implementation of a DFT matrix followed by a DAC converter only in special cases. Necessary and sufficient conditions for such cases will be given. Analyses based on the analog representation, e.g., spectral roll-off of transmitter outputs and carrier frequency offset, may not be appropriate when digital implementation is employed.
منابع مشابه
OFDM transmitters: analog representation and DFT-based implementation
The implementation of OFDM transmitters typically consists of a discrete DFT matrix and a digital-to-analog (DAC) converter. Many existing results on the analysis of OFDM systems, e.g., spectral roll-off, are based on a convenient analog representation. In this paper, we show that the analog representation and the DFT-based OFDM transmitters are equivalent only in special cases. Using the analo...
متن کاملImproved Channel Estimation for DVB-T2 Systems by Utilizing Side Information on OFDM Sparse Channel Estimation
The second generation of digital video broadcasting (DVB-T2) standard utilizes orthogonal frequency division multiplexing (OFDM) system to reduce and to compensate the channel effects by utilizing its estimation. Since wireless channels are inherently sparse, it is possible to utilize sparse representation (SR) methods to estimate the channel. In addition to sparsity feature of the channel, the...
متن کاملUsing WPT as a New Method Instead of FFT for Improving the Performance of OFDM Modulation
Orthogonal frequency division multiplexing (OFDM) is used in order to provide immunity against very hostile multipath channels in many modern communication systems.. The OFDM technique divides the total available frequency bandwidth into several narrow bands. In conventional OFDM, FFT algorithm is used to provide orthogonal subcarriers. Intersymbol interference (ISI) and intercarrier interferen...
متن کاملPAPR and Fiber Nonlinearity Mitigation of DFT-Precoded OFDM System
High Peak-to-Average Power Ratio (PAPR) is one of the major drawback of Orthogonal Frequency Division Multiplexing (OFDM) based systems that can cause intermodulation among the subcarriers due to the nonlinearities of the fiber. The high PAPR increases the complexity of the Analog to Digital (A/D) and Digital to Analog (D/A) converters. In this paper, I present an analysis of Discrete Fourier T...
متن کاملImproving adaptive resolution of analog to digital converters using least squares mean method
This paper presents an adaptive digital resolution improvement method for extrapolating and recursive analog-to-digital converters (ADCs). The presented adaptively enhanced ADC (AE-ADC) digitally estimates the digital equivalent of the input signal by utilizing an adaptive digital filter (ADF). The least mean squares (LMS) algorithm also determines the coefficients of the ADF block. In this sch...
متن کامل