722 research outputs found
Mobile Radio Channels Modeling in MATLAB
In this paper, a MATLAB based approach for mobile radio channels modeling is presented. Specifically, the paper introduces the basic concepts for modeling flat fading channels in MATLAB by means of user-defined m-files. Typical small-scale fading channel models are derived such as uncorrelated Rician fading channel and Rayleigh fading channel with Doppler shift. Further, simple and useful MATLAB constructions for approximation of cumulative distribution functions (CDFs) and probability density functions (PDFs) are also given. Finally, a MATLAB based Monte Carlo simulation example is presented, which comprises performance estimation of phase shift keying (PSK) signaling over a Rician fading channel
Convolutional/Single Parity Check Turbo Codes for Wireless Multimedia Communications
Error correction codes are widely used in digital communications to improve the Quality of Service. The Quality of Service is typically expressed in terms of maximum acceptable frame error rate and bit error rate. The key implementation issues for most powerful error correction codes are the complexity and overall encoding/decoding latency. In this paper, short-frame turbo product codes for real-time wireless multimedia communications are proposed. Performance of the proposed turbo codes is studied through simulations on an additive white Gaussian noise (AWGN) channel. The obtained results indicate that the performance of these codes is quite exceptional given their decoding complexity
Bose-Einstein condensates with F=1 and F=2. Reductions and soliton interactions of multi-component NLS models
We analyze a class of multicomponent nonlinear Schrodinger equations (MNLS)
related to the symmetric BD.I-type symmetric spaces and their reductions. We
briefly outline the direct and the inverse scattering method for the relevant
Lax operators and the soliton solutions. We use the Zakharov-Shabat dressing
method to obtain the two-soliton solution and analyze the soliton interactions
of the MNLS equations and some of their reductions.Comment: SPIE UNO-09-UN101-19, SPIE Volume: 7501, (2009
Bulk correlation functions in 2D quantum gravity
We compute bulk 3- and 4-point tachyon correlators in the 2d Liouville
gravity with non-rational matter central charge c<1, following and comparing
two approaches. The continuous CFT approach exploits the action on the tachyons
of the ground ring generators deformed by Liouville and matter ``screening
charges''. A by-product general formula for the matter 3-point OPE structure
constants is derived. We also consider a ``diagonal'' CFT of 2D quantum
gravity, in which the degenerate fields are restricted to the diagonal of the
semi-infinite Kac table. The discrete formulation of the theory is a
generalization of the ADE string theories, in which the target space is the
semi-infinite chain of points.Comment: 14 pages, 2 figure
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