Fading distribution

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

Outage Probability of Space–Time Network Coding Over Rayleigh Fading Channels

Abstract: In this paper, we analyze the outage probability of space–time network coding (STNC) in a distributed cooperative relaying system, where multiple sources transmit their information to a common destination with the help of multiple decode-and-forward (DF) relays in timedivision multiple-access (TDMA) mode. We first derive an exact closed-form expression of the outage probability for STNC with an arbitrary number of relays for independent but not necessarily identically distributed (i.n.i.d.) Rayleigh fading channels. With the developed result, we discuss the impact of the transmit SNR, the outage threshold, the number of relays, the nonorthogonal codes, and the relay position on the system performance.

Outage Probabilities of a MIMO Scheme in Shadowed Fading Channels with Micro- and Macrodiversity Reception

Abstract: A compound probability density function (pdf) model is used for the outage analysis of a multiple input multiple output (MIMO) scheme operating in shadowed fading channels. Instead of the lognormal pdf, the compound pdf uses a gamma distribution to account for shadowing, leading to a closed form expression for the pdf of the signal-to-noise ratio in a shadowed fading channel. While the mitigation of short term fading is achieved through the use of multiple transmitters and multiple receivers, the shadowing is mitigated with macrodiversity using two base stations. Taking into account the fact that shadowing has a larger correlation distance, the two base stations are treated to have nonzero correlation. It is shown that the expression for the outage probability in a MIMO scheme operating in shadowed fading channels can be written in a simple form eliminating the need for numerical evaluation of double integrals. Results demonstrate the usefulness of the approach for the analysis of MIMO schemes.

Modified adaptive multiuser detector for DS-CDMA in multipath fading

Abstract: Direct sequence code division multiple access (DS-CDMA) is the muitiplexing method used for the next generation of wireless digital standards. This paper deals with an asynchronous DS-CDMA system in which the receiver has knowledge of the signature waveform of all the users. In the presence of white Gaussian noise and channel fading, we propose an adaptive suboptimum detector for signal detection during every bit period. The performance of this detector has been compared to the one shot detector under Gaussian noise and channel fading condition.

Effect of Microdiversity and Macrodiversity on Average Bit Error Probability in Gamma-Shadowed Rician Fading Channels

Abstract: In this letter, we analyze the error performance of a mobile communication system with microdiversity and macrodiversity reception in gamma-shadowed Rician fading channels for a binary differential phase-shift keying modulation scheme. Analytical expressions for the probability density function (PDF) and moment-generating function (MGF) are derived. The average bit error probability can be calculated by averaging the conditional bit error probability over the PDF or using the MGF-based approach. Numerical results are graphically presented to show the effects of macrodiversity, correlation, number of diversity branches, and severity of both fading and shadowing.

Optimal decision strategies for acquisition of spread spectrum signals in frequency selective fading channels

Abstract: The focus of this paper is on the initial acquisition of a direct sequence spread spectrum signal utilizing a purely parallel search strategy. A purely parallel search strategy is utilized because it reduces the acquisition time compared to either serial or partially parallel strategies. In particular, the purpose of this paper is to derive the optimal decision rule, based on the maximum-likelihood criterion, for coarse acquisition of direct sequence waveforms transmitted over frequency selective fading channels. The performance of the conventional decision rule, optimized for additive white Gaussian noise and flat fading channels, and the optimal decision rule, derived in this paper, are compared. It is shown that the performance improvement increases as the number of resolvable paths increases. Furthermore, it is shown that the optimal decision rule for Rayleigh fading channels, and a decision rule which yields approximately optimal performance for Rician fading channels, are easily implemented.