The key contribution of this work is to develop transmitter and receiver algorithms in discrete-time for turbocoded offset QPSK signals. The proposed synchronization and detection techniques perform effectively at an SNR per bit close to 1.5 dB, in the presence of a frequency offset as large as 30 % of the symbol-rate and a clock offset of 25 ppm (parts per million). Due to the use of up-sampli...

This contribution proposes a minimum bit error rate (MBER) decision feedback equaliser (DFE) designed for single-input multiple-output (SIMO) systems employing a quadrature phase shift keying (QPSK) modulation scheme. It is shown that this MBER design is superior over the standard minimum mean square error DFE in the SIMO scenario considered, in terms of the achievable system bit error rate. A ...

Firstly, this paper researches on the scheme of amplitude weighting(AW) for smart antenna(SA) beamforming in linear array. With the proposed mathematical model in this paper, QPSK base-band AW is an effective method for linear SA to realize multi-user and multi-direction transmission, by which the perfect directional beam-forming can be realized with low complexity and low cost. Secondly, this ...

IEEE specifies different modulation techniques for WiMAX; namely, BPSK, QPSK, 16 QAM and 64 QAM. This paper studies the performance of Internet Protocol Television (IPTV) over Fixed WiMAX system considering different combinations of digital modulation. The performance is studied taking into account a number of key system parameters which include the variation in the video coding, path-loss, sch...

In this paper, we provide an exact closed-form expression of the effective signal-to-noise ratio (SNR) for orthogonal frequency division multiplexing (OFDM) performance under the combined effect of the phase noise, frequency offset, and amplifier nonlinearities of the soft envelope limiter (SEL). A simplified approximate expression is also obtained for the effective SNR under certain conditions...

The author considers the use of coding to reduce the peak-to-mean envelope power ratio (PMEPR) for orthogonal frequency division multiplexing (OFDM) systems. Most of the existing schemes that use coding for PMEPR reduction assume a PSK constellation. The author presents the construction of non-square M-QAM symbols from a combination of QPSK and BPSK signals when M=2 and n is an odd number. By u...

In this paper, we derive a closed-form bit error rate (BER) solution for equaland nonequal-strength L-path channels considering imperfect channel estimation. The channel model assumes independent paths with Rayleigh fading statistics in a single-cell downlink environment. By using a simple maximum likelihood (ML) estimator, the effects of the channel estimation error due to Doppler shift, resid...

The peak-to-average ratio (PAR) of a signal is commonly used for estimating the backoff required for an radio-frequency/microwave power amplifier to exhibit acceptable intermodulation distortion. In this paper, it is shown that the PAR is an inaccurate metric for predicting the backoff and can lead to improper choices for modulation with respect to the linearity–efficiency tradeoff. A specific ...

We demonstrate an all-optical phase noise mitigation scheme based on the generation, delay, and coherent summation of higher order signal harmonics. The signal, its third-order harmonic, and their corresponding delayed variant conjugates create a staircase phase-transfer function that quantizes the phase of quadrature-phase-shift-keying (QPSK) signal to mitigate phase noise. The signal and the ...