Volume 7, Issue 2, February 2016

A Device Pair Classification based Channel Slot Re-Utilization Optimization for Scalability Enhancement in Wireless Mesh Network
Pages: 1-8 (8) | [Full Text] PDF (661K)
Asha C. N., and T. G. Basavaraju
Visvesvaraya Technological University (VTU), Belgaum
Department of Computer Science and Engineering, Government SKSJ Technological Institute, K. R. Circle, Bangalore

Abstract - Wireless mesh networks (WMNs) are multihop systems which can develop the scope of remote systems, with the benefits of fast and easy deployment, high transfer speed, simple establishment and upkeep, low front expense. They are potential methods to assemble the cutting edge remote correspondence frameworks. IEEE 802.11 standard is currently the most commonly used radio technique for WMNs. Due to tremendous growth of the wireless based application services are increasing the demand for wireless communication techniques that use bandwidth more effectively. Channel slot re-utilization in multi-radio wireless mesh networks is a very challenging problem. WMNs have been adopted as back haul to connect various networks such as Wi-Fi (802.11), WI-MAX (802.16e) etc. to the internet. The slot re-utilization technique proposed so far suffer due to high collision due to improper channel slot usage approximation error. To overcome this here the author propose the cross layer optimization technique by designing a device classification based channel slot re-utilization routing strategy which considers the channel slot and node information from various layers and use some of these parameters to approximate the risk involve in channel slot re-utilization in order to improve the QoS of the network. The simulation and analytical results show the effectiveness of our proposed approach in term of channel slot re-utilization efficiency and thus helps in reducing latency for data transmission and reduce channel slot collision.
 Index Terms - Multi-radio WMN, Radio Channel Measurement, Scheduling, Routing and Medium Access Control (MAC)
Performance Comparison of Cyclic Prefix OFDM and Unique Word OFDM in the LTE Downlink
Pages: 9-14 (6) | [Full Text] PDF (909K)
Amevi Acakpovi, Abdul-Shakud Iddrisu, Nana Yaw Asabere and John Kwofie
Department of Electrical/Electronics Engineering, School of Engineering, Accra Polytechnic, Accra, Ghana
Department of Computer Science, School of Applied Sciences and Arts, Accra Polytechnic, Accra, Ghana
National Institute of Standards and Technology, Boulder, CO 80305 USA
Department of Physics, Colorado State University, Fort Collins, CO 80523 USA

Abstract - The Long Term Evolution (LTE) downlink frame structure currently uses Cyclic Prefix Orthogonal Frequency Division Multiplexing (CP-OFDM) where the bandwidth occupied by the prefix is not utilized. Optimization of this prefix could result in increased throughput and bandwidth efficiency. This paper investigates the benefits of exploiting the unused bandwidth occupied by CP in the LTE downlink frame structure by replacing it with a newly recognized bit sequence known as the unique word (UW). A modelling and simulation approach under Matlab Simulink software was adopted. The Orthogonal Frequency Division Multiplexing (OFDM) was first modelled and tested with a 2 x 2 Multiple-In-Multiple-Out (MIMO) system while the CP and UW where implemented and tested respectively for the same input parameters. Metrics of comparison included Channel Bandwidth, number of control symbols, Modulation type, coding rate and Signal-to-Noise-Ratio (SNR) as per the LTE standard. In short, the power spectral densities of the two systems were found to be similar at about 75dBW/Hz. The Bit Error Rate (BER) of the CP-OFDM was however found to be better than BER of the UW-OFDM. In terms of throughput and Spectral efficiency, the UW-OFDM was found to outperform the CP-OFDM by 15% and 7% respectively. In this study the overall performance of the UW-OFDM is found to be better than the CP-OFDM in the LTE downlink. By eliminating cyclic prefix, bandwidth efficiency was improved. This paper therefore recommends the adoption of the UW sequence instead of the CP sequence for the LTE downlink frame structure.
 Index Terms - Cyclic Prefix OFDM, Unique Word OFDM, OFDMA, LTE, BER and PSD
Performance Comparison of Blind Equalization Algorithms for Frequency Selective Channels
Pages: 15-19 (5) | [Full Text] PDF (345K)
Fazal-E-Asim, Sajid Bashir, Shafayat Abrar and Syed Ismail Shah
Department of Electrical Engineering, Institute of Space Technology, Islamabad, Pakistan
Department of Computing, Iqra University, Islamabad, Pakistan
Department of Electrical Engineering, COMSATS Institute of Information Technology, Islamabad, Pakistan
Pakistan Telecommunication Authority (PTA), Islamabad, Pakistan

Abstract - The need of blind equalization algorithms evolved due to the growing demand of high data rates in the future standards of multicast and broadcast networks. The idea is very useful for slow fading channels as blind algorithms are quite complex as compared to the training based algorithms, no one want to sacrifice the valuable and precious bandwidth for training of equalizer. The commitment of higher data rates in the proposed fifth generation (5G) of mobile communication can only be achieved with the smaller cell size and the use of millimeter waves. The training based equalizer requires separate bandwidth for training of equalizer limiting the overall channel capacity. The channel capacity can be saved if we use the blind equalization algorithms. In this paper we compared the two well known blind algorithms for channel equalization in a modern mobile communication system i.e Multimodulus algorithm (MMA) and Square Contour algorithm (SCA) respectively. The performance measuring parameters are mean square error (MSE), inter symbol interference (ISI) and bit error rate (BER). The channel selected is time invariant and frequency selective in nature having exponentially decaying power delay profile (PDP) which satisfies the properties of extended pedestrian-A model of long term evolution (LTE). The MMA algorithms performs better in the sense of minimizing MSE, ISI and a better BER. SCA shows efficient initial convergence in terms of MSE and ISI keeping in mind that SCA used second order moments and MMA used fourth order moments to minimize their cost functions respectively. Fluctuations are observed in terms of ISI for SCA but it ends with a better recovered constellation. MMA shows stability as compared to SCA in terms of step size selection.
 Index Terms - Blind Equalization, Fading, Frequency Selective, MMA, Multipath, SCA, Mean Square Error and Inter Symbol Interference
Software-Defined Network (SDN)'s Security: Analysis of Security Threats and Solutions
Pages: 20-25 (6) | [Full Text] PDF (654K)
Tooba Maryam, Saima Akbar and Muhammad Junaid
Computer Science and Engineering Department, University of Engineering & Technology, Lahore, Pakistan

Abstract - Software-Defined Networks (SDN) is a growing technology to build programmable networks as a way to simplify the advancement of networks. Its main aim is to separate forwarding hardware from control decisions. Network flexibility, speedy service provisioning and efficiency are the excellent benefits gained by the implementation of SDN. SDN's centralized controller has potential of confidentiality, manageability and programmability. Due to these outstanding characteristics, SDN is becoming popular in industry day-by-day. As SDN is getting more popular by every passing day, its security must be raised on the agenda. In this paper, a comprehensive survey of the research related to the SDN security is presented. SDN security threats and breaches are reviewed. The paper then reviews the previously presented solutions to the identified threats. We suggested Machine Learning Techniques as a solution to the most important security threat of SDN i.e. DDOS attack. And in the end a comparison between Machine Learning Techniques is also presented.
 Index Terms - Software-Defined Networking (SDN), Security, STRTIDE, DoS, DDoS and Machine Learning Techniques
A Survey on Secure Binary Image Steganography Based on Minimizing the Distortion on the Texture
Pages: 26-29 (4) | [Full Text] PDF (289K)
Honey Mol M. and Reji P.I.
Department of Computer Science and Engineering, Mohandas College of Engineering, Anad, Trivandrum

Abstract - Many of the binary image steganographic techniques only consider the flipping distortion according to the HVS (Human Visual System), which will be not secure. Here, a binary image steganographic scheme is to minimize the embedding distortion on the texture. To extract the complement, rotation, and mirroring-invariant local texture patterns (crmiLTPs) from the binary image. The weighted sum of crmiLTP changes when flipping one pixel is then used to measure the flipping distortion corresponding to that pixel. By testing on simple binary images and the new image data set, the results shows that the proposed scheme can well describe the distortions on both visual quality and statistics. This scheme generates the cover vector by dividing the scrambled image into super pixels. Experimental results show that the proposed scheme can achieve statistical security without degrading the image quality or the embedding capacity. In this paper describes survey on image steganographic techniques and steganographic techniques used with different cryptographic algorithms, to provide extra layer of Security.
 Index Terms - Binary Image, Steganography, Complement, Rotation, and Mirroring-Invariant Local Texture Pattern (crmiLTP) and Flipping Distortion Measurement

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