Fading distribution

About: Fading distribution is a research topic. Over the lifetime, 5732 publications have been published within this topic receiving 114193 citations.

Polarization of quasi-static fading channels

Abstract: This work investigates polar coding for block-fading channels. We show that polarization does occur at infinity for three types of channel multiplexers. Nevertheless, the polarization process is not unique, as it is shaped by the choice of the multiplexer. The fading-plane approach is used to study the outage behavior of polar coding at a fixed transmission rate. Two types of multiplexers are shown to provide full diversity at finite and infinite code length.

Cooperative Fading Regions for Decode and Forward Relaying

Abstract: Cooperative transmission protocols over fading channels are based on a number of relaying nodes to form virtual multi-antenna transmissions. Diversity provided by these techniques has been widely analyzed for the Rayleigh fading case. However, short range or fixed wireless communications often experience propagation environments where the fading envelope distribution is meaningfully different from Rayleigh. The main focus in this paper is to investigate the impact of fading distribution on performances of collaborative communication. Cooperative protocols are compared to co-located multi-antenna systems by introducing the concept of cooperative fading region. This is the collection of fading distributions for which relayed transmission can be regarded as a competitive option (in terms of performances) compared to multi-antenna direct (noncooperative) transmission. The analysis is dealt with by adopting the information theoretic outage probability as the performance metric. Cooperative link performances at high SNR are conveniently expressed here in terms of diversity and coding gain as outage parameters that are provided by the fading statistics of the channels involved in collaborative transmission. Advantages of cooperative transmission compared to multi-antenna are related to the propagation environment so that the analysis can be used in network design.

Information rates of time varying Rayleigh fading channels

Abstract: In this paper, information rates of mobile radio channels without channel state information (CSI) at either the transmitter or the receiver are investigated. The channel is modeled as a time varying Rayleigh fading process whose dynamics are characterized by a Doppler spectrum with specified normalized fading rate. Results are presented in terms of the block length, the normalized fading rate, and the signal-to-noise ratio (SNR), for the Clarke's Doppler spectrum and uniform spectrum.

Fast transmit antenna selection algorithms for MIMO systems with fading correlation

Abstract: Motivated by some properties of the determinant of Hermitian positive definite matrices, this paper develops some fast transmit antenna selection algorithms for MIMO systems, based on instantaneous channel information or channel statistics for a correlated fading channel. The performance of these algorithms is evaluated in terms of both the resulting system capacity and error rate. The novel G-circles method can achieve many advantages over other existing algorithms.

On the performance of adaptive MMSE detectors for a MC-CDMA system in fast fading Rayleigh channels

Abstract: Multi-carrier CDMA (MC-CDMA) is a hybrid multiple access scheme combining multi-carrier modulation (MCM or OFDM) with direct sequence spread spectrum (DS-SS). Although a common assumption in the analysis of the performance of the various MC-CDMA detectors is that they have perfect knowledge of the fading channel, this assumption is no longer valid as the fading rate (Doppler spread) of the channel increases. We examine the performance of various forms of the minimum mean square error (MMSE) detector operating in a fast fading Rayleigh channel described by a Gauss-Markov state-space model. We show that, although adaptive detection based on the LMS and RLS algorithms is possible without explicit channel estimation, a low complexity detector, termed MMSE per carrier, combined with an RLS channel estimator can achieve better performance as well as increased robustness to the selection of the adaptation parameters.