Improvement of Transmission Properties of Multimode Fibers Using Spread Spectrum Technique and a Rake Receiver Approach

Abstract

Abstract-Multimode fibers are characterized by multipath propagation of optical signals and this leads to severe intersymbol interference at the output of the fiber. In this work an approach based on the Rake receiver is proposed to overcome this drawback. An optimization algorithm was developed and appropriate software was employed to apply the proposed methodology on specific multimode fiber. Extensive simulation results were produced and are presented herein. The numerical results have shown that the order of magnitude of the maximum data rate, R, supported at different CDMA gains, in order to achieve a Bit Error Rate value smaller or equal to a convergent point, is related to the length of the multimode fiber, L, by the expression R = dL −1 with d increasing from 10 6 to 10 7 (Kbps. m) when CDMA gain increases from 50 to 500.

Study on Reflection of Dust Plasma in Polar Mesosphere to Electromagnetic Wave

“…But, it is a pity that the characteristics of dust particles in Mesosphere have not been presented with wave propagation theory. Except for plasma, reflection and transmission of others materials [16][17][18] have also developed, such as inhomogeneous slab, multimode fibers and so on. Meanwhile, many methods [19][20][21] to solve electromagnetic wave propagation are provided by scholars.…”

Adaptive Turbo-Equalizer Design for Multi-User Mobile Communication Channel

“…At the receiver end an adaptive channel estimator uses a training sequence to find the optimum tap coefficients for the equalizer. The usual RAKE receiver [11][12][13] would not yield sufficient performance due to interference. The signal r is thus processed by an adaptive equalizer, consisting of LMS or NLMS algorithm [25] & leads to estimation ofx CDMA .…”

“…The signal r is thus processed by an adaptive equalizer, consisting of LMS or NLMS algorithm [25] & leads to estimation ofx CDMA . Next a matched filter adjusted to users spreading sequences & estimates [12][13][14][15] the modulation symbols of this userx QAM,1 . Simultaneously one user is selected in the Logmap among the user of interest.…”

An Elaborate Frequency Offset Estimation for Ofdm Systems

“…The orthogonal frequency division multiplexing (OFDM) system, which is now considered as an efficient method for high rate data communication, has some advantages, for example, flexibility which is obtained against the frequency selective channel, high spectrum efficiency [1,2], and large system capacity [3][4][5][6][7][8]. So, OFDM system was selected as the standards of IEEE 802.11a, IEEE 802.11g, high wireless LAN of HIPERLAN/2, IEEE 802.…”