| Summary: | 博士 === 淡江大學 === 電機工程學系博士班 === 94 === In this work, a pre-averaging method is proposed for deriving theoretical symbol error probability (SEP) expressions for orthogonal space-time block code (OSTBC) diversity systems employing arbitrary rectangular M-QAM transmission over flat Rayleigh fading channels. Independent fading between diversity channels are assumed for simplicity as the technique of channel decorrelation has been proposed in the literature. Channel average powers may be distinctive, identical, or mixed with both. The rectangular M-QAM results are extended to square M-QAM, M-PAM, and binary antipodal signaling. All derived expressions are in elementary forms without complicated high order transcendental functions and/or unevaluated integrals and hence are strictly exact and can be readily simulated by the computer with good accuracy. We delve into the error probability performance by proposing a new derivation method, from which many new equations and properties are shown and proved. Moreover, we show that mixed Rayleigh fading results can be readily extended to various Nakagami-m fading results. We use a four transmit antenna system with a half-rate OSTBC for 16-QAM signaling as the example to demonstrate that our theoretical results are in excellent agreements with the Monte Carlo simulated results. From simulation curves, we show that, under the independent channel fading condition, channels with identical powers have better error rate performance than channels with distinctive powers. Moreover, we discuss the performance of OSTBC with generalized complex orthogonal design (GCOD) in a rather general scope, which has not been explored in depth in the literature. Thus far, the SEP expressions for OSTBC found in the literature are only restricted to complex orthogonal design (COD) or some special GCOD cases. An important discovery is that OSTBC can produce different SEP performances for different information symbols. Although our derivation is presented based on the assumption of independent fading channels, we also provide an outline for the derivation for correlative fading channels.
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