Bengt Holter

Performance analysis of a rate-adaptive dual-branch switched diversity system

In this letter, a performance analysis of a dual-branch switched diversity system operating on statistically independent and identically distributed Nakagami-m flat-fading channels is presented. An adaptive coded modulation (ACM) scheme is employed to increase the spectral efficiency of the system. The ACM scheme consists of a set of multidimensional trellis codes originally designed for additive white Gaussian noise channels, where the codes are based on quadrature amplitude modulation (QAM) signal constellations of varying size. The performance is evaluated by assuming perfect channel knowledge at both transmitter and receiver and instantaneous feedback of channel state information, conveyed from the receiver to the transmitter on an error-free feedback channel. The optimal switching threshold of the switched diversity combiner, maximizing the average spectral efficiency, is identified for spatially uncorrelated antenna branches.

Impact of Spatial Correlation on Adaptive Coded Modulation Performance in Rayleigh Fading

A performance analysis of an adaptive coded modulation (ACM) scheme operating on identically distributed and spatially correlated Rayleigh flat-fading channels is presented. In particular, we study a single-input multiple-output system where spatial diversity is exploited at the receiver by using a maximum ratio combining scheme. The ACM scheme consists of a set of multidimensional trellis codes originally designed for additive white Gaussian noise channels, with codes being based on quadrature amplitude modulation signal constellations of varying size. Rate adaptation is achieved by providing the transmitter with channel state information as predicted by the receiver. Approximate closed-form expressions for the average bit error rate and the average spectral efficiency are derived, and numerical examples are given for the case of Jakes correlation profile and maximum a posteriori optimal predictor coefficients

Performance Analysis of a Rate-Adaptive Dual-Branch Switched Diversity System

In this paper, a performance analysis of a dual- branch switched diversity system operating on identically distributed Nakagami-m fading channels is presented. An adaptive coded modulation (ACM) scheme is employed to increase the spectral efficiency of the system. The ACM scheme consists of a set of multidimensional trellis codes originally designed for additive white Gaussian noise channels, where the codes are based on quadrature amplitude modulation (QAM) signal constellations of varying size. The performance is evaluated by assuming perfect channel knowledge at the receiver and instantaneous feedback of channel state information, conveyed from the receiver to the transmitter on a zero-error feedback channel. Both spatially uncorrelated and correlated antenna branches are considered. The optimal switching threshold in terms of maximizing the average spectral efficiency is identified in the case of uncorrelated antenna branches.

Wave propagation along a thin wire antenna placed in a horizontally layered medium

A theoretical and numerical analysis of the wave propagation along a long thin wire antenna is presented. The wire antenna is assumed to be placed in a horizontally layered medium, where each layer is characterized by an individual conductivity. The current distribution along the wire antenna is derived as the solution of an electric field integral equation which is solved by the method of moments. Numerical results are presented and discussed.

Impact of spatial correlation on adaptive coded modulation performance in rayleigh fading

A performance analysis of an adaptive coded modulation (ACM) scheme operating on identically distributed and spatially correlated Rayleigh flat-fading channels is presented. In particular, a single-input multiple-output system using maximum ratio combining at the receiver is considered. The ACM scheme consists of a set of multidimensional trellis codes originally designed for additive white Gaussian noise channels, with codes being based on quadrature amplitude modulation signal constellations of varying size. Rate adaptation is achieved by providing the transmitter with channel state information as predicted by the receiver. Numerical examples are given for the case of Jakes correlation profile and maximum a posteriori-optimal predictor coefficients, and results are compared to previously published results for spatially uncorrelated channels.