Mohd Nizam Omar

5Gbps HG 0,1 and HG 0,3 optical mode division multiplexing for RoFSO

Radio-over-free-space optics (Ro-FSO) technology harnesses the large capacity of optical fiber and the mobility native to wireless networks. To increase the capacity of Ro-FSO networks, this work introduces a new optical mode division multiplexing (MDM) scheme for Ro-FSO by incorporating optical Hermite-Gaussian modes HG 0, 1 and HG 0, 3 for transmitting two distinct 2.5 Gbps data modulated on 10 GHz radio subcarriers. Signal-to-noise ratios and bit-error-rates show successful 2 × 2.5Gbps data transmission of 10GHz radio-modulated subcarriers over the two HG optical carriers through a 800m free-space channel.

An integrated priority-based cell attenuation model for dynamic cell sizing

A new, robust integrated priority-based cell attenuation model for dynamic cell sizing is proposed and simulated using real mobile traffic data. The proposed model is an integration of two main components; the modified virtual community–parallel genetic algorithm (VC-PGA) cell priority selection module and the evolving fuzzy neural network (EFuNN) mobile traffic prediction module. The VC-PGA module controls the number of cell attenuations by ordering the priority for the attenuation of all cells based on the level of mobile level of mobile traffic within each cell. The EFuNN module predicts the traffic volume of a particular cell by extracting and inserting meaningful rules through incremental, supervised real-time learning. The EFuNN module is placed in each cell and the output, the predicted mobile traffic volume of the particular cell, is sent to local and virtual community servers in the VC-PGA module. The VC-PGA module then assigns priorities for the size attenuation of all cells within the network, based on the predicted mobile traffic levels from the EFuNN module at each cell. The performance of the proposed module was evaluated on five adjacent cells in Selangor, Malaysia. Real-time predicted mobile traffic from the EFuNN structure was used to control the size of all the cells. Results obtained demonstrate the robustness of the integrated module in recognizing the temporal pattern of the mobile traffic and dynamically controlling the cell size in order to reduce the number of calls dropped.

Hybriding Intelligent Host-Based and Network-Based Stepping Stone Detections

This paper discusses the idea of hybriding intelligent host-based and network-based stepping stone detections (SSD) in order to increase detection accuracy. Experiments to measure the True Positive Rate (TPR) and False Positive Rate (FPR) for both Intelligent-Network SSD (I-NSSD) and Intelligent-Host SSD (I-HSSD) are conducted. In order to overcome the weaknesses observed from each approach, a Hybrid Intelligent SSD (HI-SSD) is proposed. The advantages of applying both approaches are preserved. The experiment results show that HI-SSD not only increases the TPR but at the same time also decreases the FPR. High TPR means that accuracy of the SSD approach increases and this is the main objective of the creation of HI-SSD.