Search

In this paper, we present a comprehensive analytical study of the symbol error rate (SER) of single‐carrier frequency‐division multiple access (SC‐FDMA) with zero‐forcing frequency domain equalization (ZF‐FDE) over a Rayleigh fading channel. SC‐FDMA is considered as a potential waveform candidate for fifth‐generation (5G) radio access networks (RANs). First, the NC fold convolution of the noise distribution of an orthogonal frequency‐division multiplexing (OFDM) system is computed for each value of the signal‐to‐noise ratio (SNR) in order to determine the noise distribution of the SC‐FDMA system. NC is the number of subcarriers assigned to a user or the size of the discrete Fourier transform (DFT) precoding. Here, we present a simple alternative method of calculating the SER by simplifying the NC fold convolution using time and amplitude scaling properties. The effects of the NC fold convolution and SNR over the computation of the SER of the SC‐FDMA system has been separated out. As a result, the proposed approach only requires the computation of the NC fold convolution once, and it is used for different values of SNR to calculate the SER of SC‐FDMA systems. [ABSTRACT FROM AUTHOR]

This paper investigates the performance of orthogonal frequency division multiplexing (OFDM) with $$\pi /4$$ -differential quadrature phase shift keying ( $$\pi /4$$ -DQPSK) modulation, over underwater acoustic (UWA) channels. The orthogonal multicarrier scheme with non-coherent detection technique results in spectrally efficient, reliable and simple receiver design. $$\pi /4$$ -QPSK has less envelop fluctuation and performs better in multipath UWA channels. It is shown that with a pair of hydrophones for reception and maximum-ratio combining (MRC) technique, one can achieve considerably low bit-error-rate (BER) at practical signal-to-noise ratio (SNR) value. Further, the BER expression for such a scheme is obtained by using the probability density function and is shown to consist of a series with fast converge rate. The series solution approximation provides a reasonable match between the simulation and the analytical results with and without the MRC diversity technique. [ABSTRACT FROM AUTHOR]