Volume 16, Issue 1, September 2012

WDM Transmission after All-Optical NRZ to CSRZ and RZ to CSRZ Format Conversion Using a SOA-NOLM [Full Text]

Mousaab M. Nahas

Abstract— This paper presents experimental results for the performance of a CSRZ format after all-optical conversion from NRZ and RZ formats using a semiconductor laser amplifier based nonlinear optical loop mirror (SOA-NOLM). The paper starts with showing successful conversion results for 4 × 10 Gbit/s WDM signals with 100 GHz spacing. The optical conversion bandwidth and limitations for the all-optical converter device is also presented. The paper then demonstrates transmission results over a 195 km fiber span for the all-optical converted CSRZ signal and its original NRZ/RZ signals. The receiver sensitivity for the converted four wavelengths is compared with the sensitivity for the original NRZ and RZ counterparts. The paper proves that the power required at the receiver for 10-9 BER is less for the converted CSRZ format in all signals. We believe that such an investigation is useful since the all-optical devices are now considered to be of key importance in current and future all-optical networks. 


Color Image Compression Using Two Dimensions Discrete Wavelet Transform (2D-DWT) [Full Text]

Samir J. AL- Muraab

Abstract - More applications of advanced communication systems (Mobile, Internet, Satellite) need small or narrow channel capacity in order to increase the information bit rate/sec, so we use the information Compression process. This study presents a system for color image compression type JPEG by using Two Dimension Discrete Wavelet Transform [2D- DWT], with some digital signal processing techniques. The results of this system are 50% compression with good accuracy and 75% compression with suitable accuracy, and with consideration the image size for display process. All programs, graphics, and the results are accomplished by using MATLAB version (7). 


An Educational Model Cellular Shape Convertor (EMCSC): A Tool That Demonstrates and Calculates the Size and Shapes of Cells in Cellular Networks [Full Text]

Jameson Mbale

Abstract -This paper introduces the Educational Model Cellular Shape Convertor (EMCSC) a tool which demonstrates and calculates the sizes and shapes of various models of cellular network cells. The size and shape of the cell is the most critical factor in a cellular system design. The tool computes the area covered, distance around, ratio of boundary length and unit area, ratio of unit area with N channels with cells, channel increased by a factor K and cell reduced by a factor M. The computed data can be used to determine the ideal shape and use the information to guide the setting up and operation of the wireless cellular network. The EMCSC tool has four major components: the Heterogeneous Shape Cell Model (HSCM), which holds the various shape models; the Automated Equation Formula Calculator (AEFC), the automated part which evaluates the formulas; the Mathematical Sorter (MS), which sorts the calculated data and User Repository (UR) which stores the data for later use by the user.