Fading distribution

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

Effective Rate Analysis in Weibull Fading Channels

Abstract: Recently, the theory of effective rate has attracted much attention, since it can take the delay aspect into account when performing channel capacity analysis. Weibull fading model is a flexible and practical model for describing fading channels in both indoor and outdoor environments. This letter derives the exact analytical expressions of effective rate over independent but not necessarily identical Weibull fading channels, which can be used in the system analysis in real-time communication scenarios. In addition, the closed-form asymptotic expressions under high signal-to-noise ratio (SNR) and low-SNR regimes are derived to provide useful insights into the effects of system and fading parameters on the effective rate.

Effect of spatial fading correlation on performance of space-time codes

Abstract: The performance of space-time codes is investigated over Rayleigh fading channels with spatially correlated fading between transmit antennas. An exact pairwise error probability is derived based on which an analytical estimate for bit error probability is computed. The analytical results are verified through computer simulation.

Level crossing rate in terms of the characteristic function: a new approach for calculating the fading rate in diversity systems

Abstract: The level crossing rate (LCR) of a random process conveys useful information about the underlying process, and is of interest in diverse engineering fields. In wireless communications, it is related to the system characteristics such as handoff, outage probability, fading rate, average duration of fades, velocity (or maximum Doppler shift) of the mobile, and the effect of diversity on fading. The LCR formula was originally derived by Rice in terms of the joint probability density function (pdf) of the underlying process and its time derivative. In this letter, we express the LCR in terms of the joint characteristic function (cf). This new formula is useful for many cases where the joint cf is simpler to derive than the associated joint pdf. As an application and for a direct-sequence code-division multiple-access system, the fading rate at the output of a RAKE receiver with either maximal ratio combiner or postdetection equal gain combiner, operating over a frequency-selective fading channel with different path statistics, is easily calculated using the new cf-based LCR formula.

Performance Analysis of Dual-Hop AF Relaying Systems over Mixed $\eta{-}\mu$ and $\kappa{-} \mu$ Fading Channels

Abstract: This paper investigates the end-to-end performance of a dual-hop amplify-and-forward (AF) relaying communication system where the source-to-relay and the relay-to-destination channels are subject to different fading conditions. The relay is assumed to either possess perfect channel state information (CSI) or have a fixed gain. We consider the case where the one hop's channel is subject to η - μ fading, whereas the other hop's channel is subject to κ- μ fading. This mixed fading propagation channel is capable of accurately modeling various practical dual-hop transmissions. Examples of such environments are encountered in micro-/macrocellular systems and/or hybrid satellite/terrestrial wireless communication systems, where typically, only the one hop's channel has a line-of-sight (LOS) component. For both CSI-assisted and fixed-gain relaying and for integer-valued fading parameters, exact analytical expressions in the form of rapidly convergent infinite series for the outage probability (OP) and average bit error probability (ABEP) of several modulation schemes are derived. Moreover, for CSI-assisted relaying and arbitrary-valued fading parameters, closed-form lower bounds [tight for high values of the signal-to-noise ratio (SNR)] for the OP and ABEP performance are obtained. The analysis is also substantiated by obtaining previously published equivalent performance expressions as special cases of our generic fading models, namely, those available for Nakagami- m and Rice fading channels. In addition, the derived analytical expressions have been numerically evaluated, and the performance evaluation results have been further validated by comparing them with equivalent results that have been obtained by means of Monte Carlo computer simulations.

Capacity of OFDM Systems Over Fading Underwater Acoustic Channels

Abstract: In this paper, we derive bounds to the channel capacity of orthogonal frequency division multiplexing (OFDM) systems over the underwater (UW) acoustic fading channel as a function of the distance between the transmitter and the receiver. The upper bound is obtained under perfect channel state information (CSI) at the receiver. The lower bound is obtained assuming the input is drawn from phase-shift keying (PSK) constellation which results in non-Gaussian distribution of the output signal and no CSI. The reduction from the upper bound is due to limited mutual information that can be conveyed by PSK constellation and the linear minimum mean square prediction error. Our UW channel deviates from the wide sense stationary and uncorrelated scattering (WSSUS) model commonly used for small bandwidths. We incorporate frequency-dependent path loss due to the acoustic propagation into each arrival path between the transmitter and the receiver. This leads the UW channel to be modeled as a frequency-dependent doubly spread fading channel characterized by the wide sense stationary and correlated scattering (WSS-non-US) fading assumption. Both Rayleigh and Ricean fading assumptions are investigated in our model. Results from the model show a gap between the upper and lower bounds which depends not only on the ranges and shape of the scattering function of the UW channel but also on the distance between the transmitter and the receiver. Our model for the scattering function was suggested by Rescheduled Acoustic Communications Experiment (RACE08) experimental data, leading to a multilag autoregressive (AR- q) model for the fading.