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The two-point moment generating function (MGF) matching technique has been used with some success to approximate the output from an MRC diversity combiner operating in correlated lognormal fading channels. The technique, however, is very sensitive to the choice of the location of the two matching points. This paper proposes to apply the principle of power conservation across the combiner to control...
In modern broadband wireless access systems such as mobile worldwide interoperability for microwave access (WiMAX) and others, repetition coding is recommended for the lowest modulation level, in addition to the mandatory concatenated Reed-Solomon and convolutional code data coding, to protect vital control information from deep fades. This paper considers repetition coding as a time-diversity technique...
In cooperative spectrum sensing, information from deeply faded local cognitive radios (CRs) needs to be eliminated from contributing to the fusion pool at the fusion center. Most current works on the subject unrealistically assume that the reporting channels between the CRs and the fusion center are free of loss and fading. In order not to waste those deeply faded CRs, this paper proposes an efficient...
In wireless communications, fading always plays an important role that affects the performance of communication systems. The composite Rayleigh-lognormal fading, also known as Suzuki fading, is widely accepted as frequently encountered by mobile radio terminals in urban areas. In this paper, we propose various moment generating function (MGF) matching methods, as well as probability density function...
It is well known in the research field of cooperative spectrum sensing that deeply faded local cognitive sensors need to be eliminated from contributing to the fusion pool at the fusion center in order to improve global detection reliability. Also, most current works on the topic unrealistically assume that the reporting channels between the cognitive sensors and the fusion center are free of loss...
Dual feedback control algorithm has proved to allow the base station to respond quickly and efficiently to the uplink bandwidth request in broadband wireless access (BWA) networks. In this algorithm the bandwidth request is calculated based on both the length of the backlogged queue and the mismatch between packet arrival and service rates. However, the physical channel quality, SNR, does not play...
It is well known that exploiting spatial diversity via cooperation of many cognitive radios leads to an increase in energy detection reliability. This is because the probability that many radio channels concurrently experience the worst shadowing and fading channel conditions decreases as the number of cooperative CRs increases. Compared to multipath fading, shadowing effects tend to produce weak...
The paper derives a more accurate upper bound for BER for M-QAM than is currently used in the literature. This allows a more thorough analysis of the power adaptation to fading conditions for optimization of spectral efficiency. By taking into account the effect of error coding gain on power adaptation, a 7-state FSMC model for the implementation of the adaptive modulation and coding scheme in WiMAX...
In order for the base station to respond quickly and efficiently to the uplink bandwidth request in broadband wireless access (BWA) networks using time-division duplex (TDD), a dual feedback control algorithm has recently been proposed. In this algorithm the bandwidth request is adjusted in accordance with both the length of the backlogged queue and the mismatch between packet arrival and service...
To protect vital control information from deep fades, repetition coding is recommended in mobile WiMAX. This paper considers repetition coding as a maximum ratio combining process and proposes an expression for the coding gain and its effect on BER. A 10-state finite state Markov channel (FSMC) model is also proposed for the implementation of the adaptive modulation and coding (AMC) scheme in mobile...
The authors consider the viability of a wavelet-based multicarrier modulation (MCM) scheme as an alternative to the current FFT-based system used in an asymmetrical digital subscriber line (ADSL). Current work tends to unfairly compare the performance of wavelet-based MCM to that of the conventional MCM. Biorthogonal wavelet bases have a quite different structure from the classical FFT-based harmonic...
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