Abslrmt-Statistical properties of generalized Rice multipath fading channels are studied. A closed-form expression for the probability density function (PDF) of the phase process is derived first. Second order statistics, in the form of the level-crossing rate (LCR) and the average duration of fades (ADF), are then investigated for an arbitrary cmssing level of the fading amplitude. Additionally, it is shown that the generalized Rice model yields a good fining to available measurement data on mobile satellite channels in the case of an environment with tight shadowing. I . INTRODUCTIONRayleigh and Rice processes are the most widely used models in the statistical description of the behavior of small scale fading in multipath propagation channels [I], [21, [31. These processes are generated by using two uncorrelated Gaussian processes having identical variances. In order to increase the flexibility of these classical models, so that they enable a better statistical fitting to real-world mobile fading channels, modifications of the these models have been studied in [4], [21, where the Gaussian processes describing the models are allowed to be cross correlated. In [21, it was shown that such extended models allow a better description of real-world mobile fading channels.Another possibility enabling the extension of the classical Rayleigh and Rice models, while keeping the basic concept used for their generation, is to assume that the underlying Gaussian processes can have different variances. Accordingly, [7]) was also subsequently studied in [SI, where the PDF of the envelope was re-derived and combined with a lognormal process to obtain a model that takes the effects of small scale fading and shadowing into account. Furthermore, in [SI the theoretical PDF of the resultant process was shown to fit accurately to measurement data on mobile satellite channels. In [9], the moment generating function of the generalized Rice process, which plays an important role in the performance analysis of transmission systems, is obtained in closed form.In this paper, we study the statistics of the generalized Rice fading channel model by deriving the PDF of the phase process, and the second order statistics of the envelope fading, i.e., the LCR and the ADF. The fitting of the first and second order statistics of the underlying fading model to available measurement data of mobile satellite channels is also considered for the case of an environment with light shadowing. In addition to the results reported in [8], it is demonstrated that the generalized Rice model is useful to describe accurately the statistics of realistic mobile radio channels. The remainder of the paper is organized as follows. The analytical generalized Rice model is described in Section 11. Section 111 contains the derivation of the PDF of the phase process, the LCR and the ADF. Comparison of the derived statistics to corresponding measurement data is reported in Section IV. Finally, Section V contains the conclusion of the papa. THE GENERALIZED RICE FADING MOD...
This paper derives explicit closed-form expressions for the joint/marginal probability density functions of the uplink/downlink multipaths' time-of-arrival (TOA) and azimuth angle-of-arrival (AOA) in a wireless-communication fading channel. These models assume that the scatterers lie within a hollowdisc and an elliptical space, respectively. These probability density functions (pdf) provide insight into the properties of the spatial wireless channel.
In this paper, we estimate the azimuth, the elevation, and the time of arrival of diffuse sources using the covariance matching estimator (COMET) algorithm. Previous works dealt with azimuth estimation of diffuse sources or azimuth and time of arrival estimation of point sources. However, in realistic situations, a tridimensional diffuse source localization is needed, which is the main objective of this paper. We show that the dimensionality of the COMET algorithm can be reduced by separating the estimation of the different source powers and the noise variance from that of the remaining parameters, namely the azimuth, the elevation, the time of arrival, and the corresponding angular and temporal spreads. As COMET still involves a multidimensional nonlinear optimization, we choose, in this purpose, the alternating projection algorithm to alleviate the corresponding complexity. The multiple signal classification (MUSIC) algorithm is processed to initialize the so-resulted algorithm. Simulations of the proposed algorithm are carried in different
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