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Orthogonal Frequency Division Multiplexing (OFDM) is considered as an effective method for overcoming problems such as noise, multi-path propagation and frequency selective fading in low voltage power-line communication (PLC). However, OFDM system is sensitive to the error of synchronization. Accurate symbol timing and carrier frequency offset estimation are crucial to the PLC system based on OFDM...
In pilot-aided OFDM systems, the minimum mean-square-error (MMSE) interpolator provides the optimum performance based on the channel statistics. And symbol timing offset (STO) introduces a linear phase rotation to data modulated on individual subcarriers. A MMSE channel estimator designed only using the wireless channel statistics performs only sub-optimally when subcarrier phase rotations due to...
In this paper, a simple and effective synchronization scheme for NC-OFDM systems is proposed. To keep the autocorrelation in the scenario of subcarriers deficiency, the preamble is consists of two identical pseudo-noise (PN) sequences instead of ZC sequences. Coarse timing estimation and fractional CFO(carrier frequency offset) estimation are completed according to the correlation between the received...
Making full use of the characteristics of the power line channel, a new blind OFDM (orthogonal frequency multiplexing) synchronization method based on Maximum Likelihood-type (ML) algorithms is proposed. This method is effective to overcome the limitations that the ML-type algorithms are not fit for the power line channel, which have multipath effect. Theoretical analysis and computer simulation results...
Time and frequency synchronization is one of the most important tasks in an OFDM system. An improved adaptive synchronization algorithm is proposed in this paper. It combines the advantages of both decreasing step-size and constant step-size algorithms, meanwhile, a bidirectional search method is introduced into the new algorithm to accelerate the tracking speed. Simulation results show that the new...
In this paper we have presented an OFDM-based channel sounder system. We can use commercial VSG (with arbitrary waveform generator) and real time VSA to conduct channel measurements. The requirement is that both VSG and VSA should have stable oscillator during the time of measurement and the frequency offset between these two equipments can be known in advance. Because the time offset was not calibrated,...
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