Dusan Drajic

The Second Order Statistics of Maximal Ratio Combining with Unbalanced Branches

In this letter, exact closed form expressions for the level crossing rate and the autocorrelation function are derived for maximum-ratio-combining with independent but unbalanced diversity branches. The novel expressions are given for Rayleigh propagation and an arbitrary number of diversity branches. The derived identities can be applied to isotropic as well as to nonisotropic scattering environment. The analytical results are validated by simulation.

Level Crossing Rates of Ricean MIMO Channel Eigenvalues for Imperfect and Outdated CSI

In this paper, the exact closed-form expressions for the level crossing rates of the multiple-input multiple output (MIMO) channel ordered eigenvalues are derived for the Ricean propagation and arbitrary channel matrix dimensions. The novel expressions can be applied for the imperfect channel state information (CSI) and feedback delay, with or without prediction. The analytical results are validated by simulation.

Level Crossing Rates in Transmit Beamforming Systems

In this paper, the second-order statistics of the signal to noise ratio (SNR) at the output of a multiple-input-multiple-output (MIMO) system employing maximal ratio combining (MRC) are analyzed. Exact expressions for the level crossing rate (LCR) and the average fade duration (AFD) are derived for the Rayleigh propagation and arbitrary channel matrix dimensions. The analytical results are validated by simulation

Performance Evaluation of Adaptive MIMO-MRC Systems with Imperfect CSI by a Markov Model

An analytical method for the performance evaluation of adaptive multiple-input-multiple-output (MIMO) system employing maximal ratio combining (MRC) by a Markov model is developed. The finite state Markov channel model parameters were determined by a new exact expression for level crossing rate of the signal to noise ratio at the output of MIMO-MRC with imperfect channel state information, derived for the Rayleigh propagation and arbitrary channel matrix dimensions. The analytical results are validated by computer simulation.

Closed-Form Level Crossing Rates Expressions of Orthogonalized Correlated MIMO Channels

In this paper, the exact closed-form expressions for the level crossing rate (LCR) and the temporal autocorrelation function (ACF) of the signal-to-noise ratio (SNR), at the output of the spatially correlated multiple-input-multiple-output (MIMO) systems with orthogonal space-time block codes (OSTBCs), are derived. The expressions are derived for the case of an arbitrary number of Rayleigh distributed branches and any form of the covariance matrix. The derived identities can be applied to isotropic and nonisotropic scattering environments, and they are validated by Monte Carlo simulations.

Combined optimal power allocation and adaptive modulation for MIMO systems with imperfect CSI

This paper presents combination of optimal power adaptation and adaptive modulation for MIMO systems with imperfect channel state information (CSI). Proposed algorithm is designed to enable high-reliable transmission with as much possible capacity, convenient for high data rate FEC systems. Effect of use of Reed-Solomon code in the case of imperfect CSI is also considered.

Second-order statistics of a maximum ratio combiner with unbalanced and unequally distributed nakagami branches

In this study, exact closed-form expressions for the second-order statistics of the signal-to-noise ratio at a maximum ratio combiner (MRC) output for a Nakagami fading channel are derived. Using the joint characteristic function for the MRC output and its time derivative, the level crossing rate, average fading duration and autocorrelation function expressions are derived for the case of independent but unbalanced diversity branches, with unequal fading parameters and an arbitrary number of diversity branches. The analytical results are validated by simulations.

Performance of the OFDM system

In this paper, the effect of timing offset, and number of subcarriers on the error probability for an orthogonal frequency division multiplexing (OFDM) system is investigated. It is shown that the probability of error increases as the value of the timing offset increases. Timing offset becomes an increasingly important concern as higher data rates are supported.

60 Years of Shannon Information Theory

In this paper an attempt is made to give a very short survey of the development of Shannon information theory. Also, some thoughts concerning the future of information theory are given.

Level Crossing Rates of MIMO-MRC Ricean Channels and Their Implications on Adaptive Systems

The second-order statistics of the time varying signal to noise ratio at the output of a multiple-input-multiple-output(MIMO) system with maximal ratio combining (MRC) are analyzed. Exact closed-form expressions for the level crossing rate and the average fade duration are derived for the Ricean propagation and arbitrary channel matrix dimensions. Novel expressions are compared with the special case of MRC receive diversity. The analytical results are validated by simulation.