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The downlink capacity performance of distributed antenna systems (DAS) with antennas selection is investigated in a composite fading channel which takes path loss, Rayleigh fading and lognormal shadowing into account. According to the performance analysis, and using log-normal distribution approximation, the tightly approximate closed-form expressions of cumulative distribution function (CDF) and...
In this paper, the bit error rate (BER) performance of multiuser multiple-input multiple-output (MIMO) systems over Rayleigh fading channels is studied, and corresponding asymptotic performance is analyzed. Based on the asymptotic analysis at high signal to noise ratio (SNR), using the probability density functions (PDF) of the instantaneous channel power gain, the diversity gain and coding gain of...
In this paper, the downlink bit error rate (BER) performance of distributed antenna systems (DAS) with antenna selection over a composite fading channel is presented, where path loss, Rayleigh fading and lognormal shadowing are all considered for practicability. According to the performance analysis, and using the gamma distribution to approach log-normal distribution, an approximate closed-form expression...
Discrete-rate adaptive modulation (AM) scheme for distributed antenna system (DAS) with imperfect channel state information (CSI) is developed, and the corresponding performance is investigated in composite Rayleigh channel. Subject to target bit error rate (BER) constraint, an improved fixed switching threshold (FST) for the AM scheme is presented by means of tightly-approximate BER expression, and...
In order to effectively integrate and share the enormous dispersed digital media resources, we propose Digital Media Cloud (DMCloud), aiming to integrate and share the distributed digital media resources and provide digital media synthesis services. In this paper, we construct a conceptual prototype for DMCloud. Firstly, we build a digital media resource unified view to manage resources, and develop...
Based on the imperfect channel state information (CSI) from noisy channel estimation, the performance analysis of OFDM systems with continuous-rate adaptive modulation (AM) and imperfect estimation in Rayleigh fading channels is presented. Subject to a target bit error rate (BER) constraint, the average spectral efficiency (SE) of the system with imperfect CSI is analyzed and derived, and the conditional...
The performance analysis of a space-time coded multiple-input multiple-output (MIMO) system with variable-rate adaptive modulation over flat Rayleigh fading channels for both perfect and imperfect channel state information (CSI) is presented. In this study, the optimum fading gain switching thresholds for attaining maximum spectrum efficiency (SE) subject to an average bit error rate (BER) constraint...
By combining adaptive modulation (AM) and automatic repeat request (ARQ), a cross-layer design (CLD) scheme for MIMO system with space-time block coding (STBC) and imperfect channel state information (CSI) is presented in this paper, and the effect of the imperfect CSI on the system performance is investigated. Based on the imperfect CSI, the probability density function of the effective signal to...
Improving the precision of shot boundary detection is very important. This paper presents an algorithm for shot boundary detection based on SVM (support vector machine) in compressed domain. It uses the features, such as the type of macroblock, the difference between DC coefficients of two co-located blocks in successive frames and the type of frame, to segment a video into the shots by classifying...
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