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Fast Fourier transform (FFT) 2

Coding gain 1

Computational complexity 1

Cyclic prefix (CP) 1

FFT 1

Inter carrier interference (ICI) 1

Inter symbol interference (ISI) 1

Low-density parity-check (LDPC) codes 1

Maximum likelihood estimation (MLE) 1

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Orthogonal frequency division multiplexing (OFDM) 1

Sum-product algorithm (SPA) 1

regular pulse excitedlong term prediction 1

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A novel energy-efficient ICI cancellation technique for bandwidth improvements through cyclic prefix reuse in an OFDM system Article

Sandeep SAROWA, Harmanjeet SINGH, Sunil AGRAWAL, B. S. SOHI

Frontiers of Information Technology & Electronic Engineering 2017, Volume 18, Issue 11, Pages 1892-1899 doi: 10.1631/FITEE.1601333

Abstract: Orthogonal frequency division multiplexing (OFDM), a very promising technique that is leading the evolution in wireless mobile communication to sideline the bandwidth scarcity issue in spectrum allocation, is severely affected by the undesirable effects of the frequency offset error, which generates inter carrier interference (ICI) due to the Doppler shift and local oscillator frequency synchronization errors. There are many ICI cancellation techniques available in the literature, such as self-cancellation (SC), maximum likelihood estimation (MLE), and windowing, but they present a tradeoff between bandwidth redundancy and system complexity. In this study, a new energy-efficient, bandwidth-effective technique is proposed to mitigate ICI through cyclic prefix (CP) reuse at the receiver end. Unlike SC and MLE where the whole OFDM symbol data is transmitted in duplicate to create redundancy at the transmitter end, the proposed technique uses the CP data (which is only 20% of the total symbol bandwidth) to estimate the channel, and it produces similar results with a huge bandwidth saving. The simulation results show that the proposed technique has a significant improvement in error performance, and a comparative analysis demonstrates the substantial improvement in energy efficiency with high bandwidth gain. Therefore, it outperforms the legacy ICI cancellation schemes under consideration.

Keywords： Orthogonal frequency division multiplexing (OFDM) Fast Fourier transform (FFT) Cyclic prefix (CP)

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An improved low-complexity sum-product decoding algorithm for low-density parity-check codes

Michaelraj Kingston ROBERTS,Ramesh JAYABALAN

Frontiers of Information Technology & Electronic Engineering 2015, Volume 16, Issue 6, Pages 511-518 doi: 10.1631/FITEE.1400269

Abstract: proposed algorithm, reduction in computational complexity is achieved by utilizing fast Fourier transform (FFT

Keywords： Computational complexity Coding gain Fast Fourier transform (FFT) Low-density parity-check (LDPC)

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An End to End Modulating Transmission Scheme With Good Robustness Against the RPE-LTP Vocoder

Chen Liquan,Hu Aiqun,Xu Qing and Yang Xiaohui

Strategic Study of CAE 2007, Volume 9, Issue 12, Pages 81-85

Abstract:

A novel endtoend data transmission scheme based on OFDM mechanism with good robustness against the RPE-LTP vocoder in GSM voice channel is proposed. According to the character of RPE-LTP vocoder, data are modulated to orthogonal lowfrequency sinusoidal carrier. In OFDM, the modulation is done by IFFT and the modulated signals are conformed to the time and frequency characters of RPELTP vocoder. The results of simulation show that the transmission bit rate of the proposed scheme reaches 2.4 kb/s，and the bit error rate of the scheme is lower than 0.3 %. This scheme provides a new approach for realtime secure voice data transmission over GSM system.

Keywords： vocoder regular pulse excitedlong term prediction OFDM FFT