The necessary and sufficient condition for beamforming optimality for multiple-input multiple output (MIMO) systems with mean feedback has been derived and thoroughly investigated in this article. The condition is an inequality that contains parameters of the number of antennas, transmission power, and the singular values of channel mean matrix. When the beamforming optimality condition is sati...

The Shannon capacity of a graph G is c(G) = supd>1(α(G d)) 1 d , where α(G) is the independence number of G. The Shannon capacity of the Kneser graph KGn,r was determined by Lovász in 1979, but little is known about the Shannon capacity of the complement of that graph when r does not divide n. The complement of the Kneser graph, KGn,2, is also called the triangular graph Tn. The graph Tn has th...

Abstract This paper uses observations from two British Columbia studies to illustrate the shortcomings of widely used ratio-based approaches for residential long-term care capacity planning. It shows that capacity plans based on a fixed ratio of beds per population over age 75 may result in either excess capacity or long wait times for admission. It then investigates the use of linear regressio...

Introduction: The forced expiratory flow at 25 and 75% of the pulmonary volume/forced vital capacity ratio (FEF25-75/FVC) as a spirometry parameter has been successful in the early diagnosis of chronic obstructive pulmonary disease (COPD) and the methacholine challenge test for assessing airway responsiveness.To determine the accuracy of FEF25-7...

This paper proposes a vertical beamforming concept to a cellular network employing Fractional Frequency Reuse technique including with cell sectorization. Two different beams are utilized in cell-center and cell-edge, separately. The proposed concept is validated through computer simulation in term of SINR and channel capacity. Also, comparison when utilizing horizontal and vertical beam format...

In this two-part paper, we consider the transmission of confidential data over wireless wiretap channels. The first part presents an information-theoretic problem formulation in which two legitimate partners communicate over a quasi-static fading channel and an eavesdropper observes their transmissions through another independent quasi-static fading channel. We define the secrecy capacity in te...

The capacity of MIMO systems under ideal (i.i.d.) channel conditions has been shown to increase linearly with the number of antennas. Capacity scaling is observed in a correlated channel environment as well but the constant of scaling is shown in [7] to be less than that of the i.i.d. scaling factor. Using a channel representation motivated by physical scattering considerations, the virtual cha...

In this paper, a novel unified analytical expression for average bit error rates (ABER) and average channel capacity (ACC) is presented for the – shadowed fading model. This model has recently shown to be suitable for underwater acoustic wireless channel modeling using the measurements conducted by the Naval Research Laboratory [1], and is not so well covered in the public literature. Deploying...

In this paper we investigate the performance of MIMO systems in co-channel interference. We present a way of explicitly examining the effect of interference on the MIMO sub-channel gains. Using this, we derive upper and lower asymptotic bounds on capacity with many interferers and in high interference-to-noise ratio. Simulation results are presented for these bounds and for the performance of M...

There are two kinds of MIMO systems [1], such as spatial multiplexing method and diversity method. To enhance the channel capacity, the space multiplexing method is effective in high SNR environment, while the diversity method is effective in low SNR environment. The channel capacity improvement combining two transmission methods is expected by selecting on appropriate methods depending on the ...