Multipath fading compensation techniques using pilot and data symbols in mobile radio channels

Abstract

The paper studies techniques for transmitting a 16-ary quadrature-amplitude modulated (16QAM) signal in different mobile radio environments. Conventional multipath fading compensation techniques using only the pilot symbols, incorporated with zeroth-order and firstorder prediction methods, are studied. Novel techniques making use both the pilot symbols and the data symbols, together with the improved zeroth-order and first-order prediction methods, are proposed. A series of intensive Monte Carlo simulations has been carried out on these techniques and the results have shown that, at high signal-tonoise ratios (SNRs), the bit-error rate (BER) performance can be reduced by a factor of about 46 and 2 using the improved zeroth-order and first-order prediction respectively, relative to those obtained using the pilot symbols only.

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“…Among these spectrally efficient signals, the 16-ary phase-shift keyed (16PSK) and 16-ary quadrature-amplitude-modulated (16QAM) signals with a theoretical spectral efficiency of four bit/s/Hz are promising candidates because of their relative simplicity of implementation and good bit-error-rate (BER) performance through linear channels [1][2]. Recently, the pilot-symbol-aided (PSA) transmission techniques have been proposed to compensate the signal distortion when this type of signals is transmitted in the fading channels [3][4][5][6][7][8][9]. In a PSA system, the transmitted data-symbol sequence is divided into frames of data symbols.…”

“…In these studies, the fading estimation processes make use of only the pilot symbols but ignore the fading distortion information in the data symbols [3][4][5][6][7]. Several simple estimation techniques that make use of the data symbols as well as the pilot symbols to enhance the accuracy of the estimation process have been proposed by the authors [8][9]. Studies have shown that, in the frequency non-selective fading channels, substantial improvements on BER performances of the signals can be achieved by using both the pilot and data symbols, instead of only the pilot symbols, for fading estimation.…”

“…This paper studies a first-order estimation technique [8] to be used in the frequencyselective and frequency-nonselective Rayleigh fading channels that corrupted by co-channel interference (CCI) or additive white Gaussian noise (AWGN). The major advantages of the proposed technique are its simple implementation and the short storage-delay time introduced.…”