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  • 1.
    Abdelsamad, Deena
    Blekinge Institute of Technology, School of Engineering.
    Video Transmission Jerkiness Measure2013Independent thesis Basic level (degree of Bachelor)Student thesis
    Abstract [en]

    Digital video transmission is widely used nowadays in multimedia. Frame dropping, freeze and reduced number of frames in the transmitted video are common symptoms of bad transmission quality. In order to assess the quality of transmission, a criterion is introduced in a model for a no reference video jerkiness measure [3]. This model is dierent from the former models presented as it depends on viewing conditions and video resolutions, so it is applicable for any frame size from QCIF to HD. The model uses simple mathematical equations of jerkiness and can be used for any video sequence [3]. A model of reduced reference method (Qtransmission) which depends on a pre-measured Jerkiness is introduced as a suggestion of future work.

  • 2.
    Abelsson, Sara
    Blekinge Institute of Technology, School of Engineering, Department of Signal Processing.
    Propagation Measurements at 3.5 GHz for WiMAX2007Independent thesis Advanced level (degree of Master (One Year))Student thesis
    Abstract [en]

    Propagation measurements at the frequency 3.5 GHz for the WiMAX technology have been conducted. The purpose of these measurements is that a coverage analysis should be accomplished. The mathematical software package MATLAB has been used to analyze the collected data from the measurement campaign. Path loss models have also been used and a comparison between these models and the collected data has been performed. An analysis prediction tool from an application called WRAP has also been used in the comparison with the collected data. In this thesis, diff

  • 3.
    Abualhana, Munther
    et al.
    Blekinge Institute of Technology, School of Computing.
    Tariq, Ubaid
    Blekinge Institute of Technology, School of Computing.
    Improving QoE over IPTV using FEC and Retransmission2009Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    IPTV (Internet Protocol Television), a new and modern concept of emerging technologies with focus on providing cutting edge high-resolution television, broadcast, and other fascinating services, is now easily available with only requirement of high-speed internet. Everytime a new technology is made local, it faces tremendous problems whether from technological point of view to enhance the performance or when it comes down to satisfy the customers. This cutting edge technology has provided researchers to embark and play with different tools to provide better quality while focusing on existing tools. Our target in dissertation is to provide a few interesting facets of IPTV and come up with a concept of introducing an imaginary cache that can re-collect the packets travelling from streaming server to the end user. In the access node this cache would be fixed and then on the basis of certain pre-assumed research work we can conclude how quick retransmission can take place when the end user responds back using RTCP protocol and asks for the retransmission of corrupted/lost packets. In the last section, we plot our scenario of streaming server on one side and client, end user on the other end and make assumption on the basis of throughput, response time and traffic.

  • 4.
    Adapa, Sasank Sai Sujan
    Blekinge Institute of Technology, Faculty of Computing, Department of Communication Systems.
    APPLYING LEAN PRINCIPLES FOR PERFORMANCE ORIENTED SERVICE DESIGN OF VIRTUAL NETWORK FUNCTIONS FOR NFV INFRASTRUCTURE: Concepts of Lean2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Context. Network Function Virtualization was recently proposed by European Telecommunications Standards Institute (ETSI) to improve the network service flexibility by virtualization of network services and applications that run on hardware. To virtualize network functions, the software is decoupled from underlying physical hardware. NFV aims to transform industries by reducing capital investments on hardware by using commercial-of-the-shelf (COTS) hardware. NFV makes rapid innovative growth in telecom services through software based service deployment.

    Objectives. This thesis work aims to investigate how business organizations function and the roles in defining a service relationship model. The work also aims to define a service relationship model and to validate it via proof of concept using network function virtualization as a service. For this thesis, we finally apply lean principles for the defined service relationship model to reduce waste and investigate how lean benefits the model to be proven as performance service oriented.

    Methods. The essence of this work is to make a business organization lean by investigating its actions and applying lean principles. To elaborate, this thesis work involves in a research of papers from IEEE, TMF, IETF and Ericsson. It results in modelling of a PoC by following requirement analysis methodology and by applying lean principles to eliminate unnecessary processes which doesn’t add any value.

    Results. The results of the work include a full-fledged service relationship model that include three service levels with roles that can fit in to requirement specifications of NFV infrastructure. The results also show the service levels functionalities and their relationships between the roles. It has also been observed that the services that are needed to be standardized are defined with syntax for ways to describe network functions. It is observed that lean principles benefit the service relationship model from reducing waste factors and hereby providing a PoC which is performance service oriented.

    Conclusions. We conclude that roles defined are fit for the service relationship model designed. Moreover, we conclude that the model can hence contain the flow of service by standardizing the subservices and reducing waste interpreted with lean principles and there is a need for further use case proof of the model in full scale industry trials. It also concludes the ways to describe network functions syntax which follows lean principles that are essential to have them for the sub-services standardization. However, PoC defined can be an assurance to the NFV infrastructure.

  • 5.
    Addu, Raj Kiran
    et al.
    Blekinge Institute of Technology, Faculty of Computing, Department of Communication Systems.
    Potuvardanam, Vinod Kumar
    Blekinge Institute of Technology, Faculty of Computing, Department of Communication Systems.
    Effect of Codec Performance on Video QoE for videos encoded with Xvid, H.264 and WebM/VP82014Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    In recent years, there has been a significant growth in multimedia services such as mobile video streaming, Video-on-Demand and video conferencing. This has led to the development of various video coding techniques, aiming to deliver high quality video while using available bandwidth efficiently. This upsurge in the usage of video applications has also resulted in making endusers more quality-conscious. In order to meet the users’ expectations, the Quality of Experience (QoE) studies has gained utmost importance from both researchers and service providers. This thesis aims to compare the performance of H.264/AVC, Xvid and WebM/VP8 video codecs in wired and wireless networks. The codec performance is evaluated for different packet loss and delay variation values. The evaluation of codec performance is done using both subjective and objective assessment methods. In subjective assessment method, the evaluation of video codec performance is done using ITU-T recommended Absolute Category Rating (ACR) method. Using this method the perceptual video quality ratings are taken from the users, which are then averaged to obtain Mean Opinion Score. These obtained scores are used to analyze the performance of encoded videos with respect to users’ perception. In addition to subjective assessment method, the quality of encoded video is also measured using objective assessment method. The objective metric SSIM (Structural Similarity) is used to evaluate the performance of encoded videos. Based on the results, it was found that for lower packet loss and delay variation values H.264 showed better results when compared to Xvid and WebM/VP8 whereas, WebM/VP8 outperformed Xvid and H.264 for higher packet loss and delay variation values. On the whole, H.264 and WebM/VP8 performed better than Xvid. It was also found that all three video codecs performed better in wired network when compared to the wireless network.

  • 6.
    Adebomi, OYEKANLU Emmanuel
    et al.
    Blekinge Institute of Technology, School of Computing.
    Mwela, JOHN Samson
    Blekinge Institute of Technology, School of Computing.
    Impact of Packet Losses on the Quality of Video Streaming2010Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    In this thesis, the impact of packet losses on the quality of received videos sent across a network that exhibit normal network perturbations such as jitters, delays, packet drops etc has been examined. Dynamic behavior of a normal network has been simulated using Linux and the Network Emulator (NetEm). Peoples’ perceptions on the quality of the received video were used in rating the qualities of several videos with differing speeds. In accordance with ITU’s guideline of using Mean Opinion Scores (MOS), the effects of packet drops were analyzed. Excel and Matlab were used as tools in analyzing the peoples’ opinions which indicates the impacts that different loss rates has on the transmitted videos. Statistical methods used for evaluation of data are mean and variance. We conclude that people have convergence of opinions when losses become extremely high on videos with highly variable scene changes

  • 7.
    Adeleke, Adesina
    Blekinge Institute of Technology, School of Management.
    How External Forces are influencing the Ebusiness strategy of MTN-Nigeria2009Independent thesis Advanced level (degree of Master (One Year))Student thesis
    Abstract [en]

    The Internet and e-business has had enormous impact on many companies in Nigeria and there has been much research on how e-business influences the environment, but little can be found on how the environment of a developing country like Nigeria influences e-business. In e-business, technology tells the business what can be done in smarter ways. Technology not only can make business more efficient but also can make business more effective in targeting and reaching markets, however technology cannot enhance business in isolation as there are other vital factors that equally impact business. This thesis presents an adapted version of the PESTEL (Political, Economic, Socio cultural, Technology, Environment, and Legal) framework so called e-business PESTEL framework, as a method for structural analysis of macro environment forces in the future. In addition to this PESTEL framework, the Porter’s five forces model was employed to analyse the industrial forces that also influence MTNN e-business strategy. The main goal of this research is to give an overview of industry and macro-environment forces influencing the e-business strategy MTN-Nigeria and the impact of future developments. The research methodology was explorative and descriptive. A further method for future analysis of the macro-environments influences and a suggestion on how to incorporate it in this research work is given. The e-business strategy of MTNN consists of four areas: E-procurement, E-collaboration (CRM), Supply chain management and E-commerce. The influences found on macro-environments level are political and sociocultural forces and in the industry levels are bargaining power of customers and suppliers of its products and services .The most recommendations are that MTN-Nigeria should add e-business PESTEL framework described in this thesis to its e-business strategy check. Furthermore MTNN should include environment analysis more extensively in their e-business strategy approach as the factors in this research work shape the environment in which it carries out its business.

  • 8.
    Adidamu, Naga Shruti
    et al.
    Blekinge Institute of Technology, Faculty of Computing, Department of Computer Science and Engineering.
    Bheemisetty, Shanmukha Sai
    Blekinge Institute of Technology, Faculty of Computing, Department of Computer Science and Engineering.
    Assessment of Ixia BreakingPoint Virtual Edition: Evolved Packet Gateway2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 9.
    Adolfsson, Henrik
    et al.
    Blekinge Institute of Technology, School of Engineering, Department of Telecommunication Systems.
    Svensson, Peter
    Blekinge Institute of Technology, School of Engineering, Department of Telecommunication Systems.
    Design and implementation of the MMS portal2006Independent thesis Basic level (degree of Bachelor)Student thesis
    Abstract [en]

    MMS-enabled terminals on the market today are very complicated to use. It takes several steps to create a multi-slide MMS-message with images and text. This discourages users from using it. To increase usage of MMS, several companies provide web-based or stand-alone programs that allow users to create and send MMS-messages from a regular computer. However these editors have many limitations and are not user-friendly. This thesis describes the design and implementation of a user-friendly web-based MMS-portal where users can create, edit and send MMS-messages. The portal is integrated into Densitet’s system for development of mobile services. Conclusions that can be draw from this work are that problems with MMS interoperability have mostly the poor standardization to blame. Different terminals support different types of images and sound formats, and to make the MMS-portal user-friendly, format conversions of uploaded content had to be implemented. Also the MMS-portal only supports basic MMS-functionality. If the MMS-specification includes more audio and image formats and if the MMS-terminals are upgraded to handle these formats, sending MMS-messages will be easier and mobile messaging will continue to grow.

  • 10.
    Advaita, Advaita
    et al.
    Blekinge Institute of Technology, Faculty of Computing, Department of Creative Technologies.
    Gali, Mani Meghala
    Blekinge Institute of Technology, Faculty of Computing, Department of Creative Technologies.
    Chu, Thi My Chinh
    Blekinge Institute of Technology, Faculty of Computing, Department of Creative Technologies.
    Zepernick, Hans-Juergen
    Blekinge Institute of Technology, Faculty of Computing, Department of Creative Technologies. Blekinge Inst Technol, SE-37179 Karlskrona, Sweden..
    Outage Probability of MIMO Cognitive Cooperative Radio Networks with Multiple AF Relays Using Orthogonal Space-Time Block Codes2017In: 2017 IEEE 13TH INTERNATIONAL CONFERENCE ON WIRELESS AND MOBILE COMPUTING, NETWORKING AND COMMUNICATIONS (WIMOB), IEEE , 2017, p. 84-89Conference paper (Refereed)
    Abstract [en]

    In this paper, we analyze the outage probability of multiple-input multiple-output cognitive cooperative radio networks (CCRNs) with multiple opportunistic amplify-and-forward relays. The CCRN applies underlay spectrum access accounting for the interference power constraint of a primary network and utilizes orthogonal space-time block coding to transmit multiple data streams across a number of antennas over several time slots. As such, the system exploits both time and space diversity to improve the transmission reliability over Nakagami.. fading. The CCRN applies opportunistic relaying in which the relay offering the highest signal-to-noise ratio at the receiver is selected to forward the transmit signal. Furthermore, selection combining is adopted at the secondary receiver to process the signal from the direct and relaying transmissions. To evaluate system performance, we derive an expression for the outage probability which is valid for an arbitrary number of antennas at the source, relays, and receiver of the CCRN. Selected numerical results are provided using Mathematica for analysis and Matlab for simulations, to reveal the effect of network parameters on the outage probability of the system.

  • 11.
    Afaq, Muhammad
    et al.
    Blekinge Institute of Technology, School of Engineering.
    Faheem, Sahibzada Muhammad
    Blekinge Institute of Technology, School of Engineering.
    Performance Analysis of Selected Cooperative Relaying Techniques2010Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    Recently, cooperative communication has gained significant interest due to the fact that it exploits spatial diversity and provides capacity/performance gain over conventional single- input single-output (SISO) systems. A mobile node with single antenna can cooperate with a nearby mobile node having single antenna in multi-user environment to create the effect of virtual multiple antenna system. Hence, reducing the complexity associated with actual multiple antenna systems. Despite the small size and power constraints, a mobile node can still benefit from spatial diversity by employing cooperation, thus saving transmission power and increasing the coverage range of the network. In this thesis, we have selected some of relaying protocols, namely, amplify-and-forward, decode-and-forward, detect-and-forward, and selective detect-and-forward that are studied and implemented for two different relaying geometries, i.e. equidistant and collinear. Results are studied and compared with each other to show the performance of each protocol in terms of average symbol error probabilities. The considered system model has three nodes, i.e. source, relay, destination. Communicating nodes are considered to be half-duplex with single antenna for transmission and reception. The source, when communicating with the destination, broadcasts the information, which is heard by the nearby relay. The relay then uses one of the cooperation protocols. Finally, the relayed signal reaches the destination, where it is detected by maximal ratio combiner (MRC) and combined with the direct transmission for possible diversity gains. The transmission path or the channel is modeled as a frequency non-selective Rayleigh fading in the presence additive white Gaussian noise (AWGN). The effect of path loss has been observed on cooperation for collinear arrangement with exponential decay up to four. Considering equidistant arrangement, decode-and-forward shows good performance at high signal-to-noise ratio (SNR) while amplify-and-forward is very promising for very low SNR. A selective relaying scheme called selective detect-and- forward is also presented which outperforms its fixed counterparts for a wide range of SNR.

  • 12.
    Aftab, Adnan
    et al.
    Blekinge Institute of Technology, School of Computing.
    Mufti, Muhammad Nabeel
    Blekinge Institute of Technology, School of Computing.
    Spectrum sensing through implementation of USRP22011Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    Scarcity of the wireless spectrum has led to the development of new techniques for better utilization of the wireless spectrum. Demand for high data rates and better voice quality is resulting in the development of new wireless standard making wireless spectrum limited than ever. In this era of wireless communication, service providers and telecom operators are faced with a dilemma where they need a large sum of the wireless spectrum to meet the ever increasing quality of service requirements of consumers. This has led to the development of spectrum sensing techniques to find the unused spectrum in the available frequency band. The results presented in this thesis will help out in developing clear understanding of spectrum sensing techniques. Comparison of different spectrum sensing approaches. The experiments carried out using USRP2 and GNU radio will help the reader to understand the concept of underutilized frequency band and its importance in Cognitive Radios.

  • 13.
    Ahmad, Nadeem
    et al.
    Blekinge Institute of Technology, School of Computing.
    Habib, M. Kashif
    Blekinge Institute of Technology, School of Computing.
    Analysis of Network Security Threats and Vulnerabilities by Development & Implementation of a Security Network Monitoring Solution2010Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    Communication of confidential data over the internet is becoming more frequent every day. Individuals and organizations are sending their confidential data electronically. It is also common that hackers target these networks. In current times, protecting the data, software and hardware from viruses is, now more than ever, a need and not just a concern. What you need to know about networks these days? How security is implemented to ensure a network? How is security managed? In this paper we will try to address the above questions and give an idea of where we are now standing with the security of the network.

  • 14.
    Ahmad, Naseer
    Blekinge Institute of Technology, School of Engineering, Department of Telecommunication Systems.
    Security Issues in Wireless Systems2009Independent thesis Advanced level (degree of Master (One Year))Student thesis
    Abstract [en]

    ireless Communication is one of the fields of Telecommunications which is growing with the tremendous speed. With the passage of time wireless communication devices are becoming more and more common. It is not only the technology of business but now people are using it to perform their daily tasks, be it for calling, shopping, checking their emails or transfer their money. Wireless communication devices include cellular phones, cordless phones and satellite phones, smart phones like Personal Digital Assistants (PDA), two way pagers, and lots of their devices are on their way to improve this wireless world. In order to establish two way communications, a wireless link may be using radio waves or Infrared light. The Wireless communication technologies have become increasingly popular in our everyday life. The hand held devices like Personal Digital Assistants (PDA) allow the users to access calendars, mails, addresses, phone number lists and the internet. Personal digital assistants (PDA) and smart phones can store large amounts of data and connect to a broad spectrum of networks, making them as important and sensitive computing platforms as laptop PCs when it comes to an organization’s security plan. Today’s mobile devices offer many benefits to enterprises. Mobile phones, hand held computers and other wireless systems are becoming a tempting target for virus writers. Mobile devices are the new frontier for viruses, spam and other potential security threats. Most viruses, Trojans and worms have already been created that exploit vulnerabilities. With an increasing amount of information being sent through wireless channels, new threats are opening up. Viruses have been growing fast as handsets increasingly resemble small computers that connect with each other and the internet. Hackers have also discovered that many corporate wireless local area networks (WLAN) in major cities were not properly secured. Mobile phone operators say that it is only a matter of time before the wireless world is hit by the same sorts of viruses and worms that attack computer software.

  • 15.
    Ahmad, Waqas
    et al.
    Blekinge Institute of Technology, School of Engineering.
    Aslam, Muhammad Kashif
    Blekinge Institute of Technology, School of Engineering.
    An investigation of Routing Protocols in Wireless Mesh Networks (WMNs) under certain Parameters2009Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    Wireless Mesh Networks (WMNs) are bringing revolutionary change in the field of wireless networking. It is a trustworthy technology in applications like broadband home networking, network management and latest transportation systems. WMNs consist of mesh routers, mesh clients and gateways. It is a special kind of wireless Ad-hoc networks. One of the issues in WMNs is resource management which includes routing and for routing there are particular routing protocols that gives better performance when checked with certain parameters. Parameters in WMNs include delay, throughput, network load etc. There are two types of routing protocols i.e. reactive protocols and proactive protocols. Three routing protocols AODV, DSR and OLSR have been tested in WMNs under certain parameters which are delay, throughput and network load. The testing of these protocols will be performed in the Optimized Network Evaluation Tool (OPNET) Modeler 14.5. The obtained results from OPNET will be displayed in this thesis in the form of graphs. This thesis will help in validating which routing protocol will give the best performance under the assumed conditions. Moreover this thesis report will help in doing more research in future in this area and help in generating new ideas in this research area that will enhance and bring new features in WMNs.

  • 16.
    Ahmadi Mehri, Vida
    et al.
    Blekinge Institute of Technology, Faculty of Computing, Department of Computer Science and Engineering.
    Ilie, Dragos
    Blekinge Institute of Technology, Faculty of Computing, Department of Computer Science and Engineering.
    Tutschku, Kurt
    Towards Privacy Requirements for Collaborative Development of AI Applications2018In: 14th Swedish National Computer Networking Workshop (SNCNW), 2018Conference paper (Refereed)
    Abstract [en]

    The use of data is essential for the capabilities of Data- driven Artificial intelligence (AI), Deep Learning and Big Data analysis techniques. The use of data, however, raises intrinsically the concern of the data privacy, in particular for the individuals that provide data. Hence, data privacy is considered as one of the main non-functional features of the Next Generation Internet. This paper describes the privacy challenges and requirements for collaborative AI application development. We investigate the constraints of using digital right management for supporting collaboration to address the privacy requirements in the regulation.

  • 17.
    ahmed, amar
    Blekinge Institute of Technology, School of Engineering, Department of Telecommunication Systems.
    Performance and Modeling of SIP Session Setup2009Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    During the recent last years, transport of multimedia sessions, such as audio streams and video conferences, over IP has acquired a lot of attention since most of communication technologies are migrating to work over IP. However, sending media streams over IP networks has encountered some problems related to signaling issues. The ongoing research in this area has produced some solutions to this subject. Internet Engineering Task Force (IETF) has introduced Session Initiation Protocol (SIP), which has proved to be an efficient protocol for controlling sessions over IP. While a great deal of research performed in evaluating the performance of SIP and comparing it with its competent protocols such as H.323, studying the delay caused by initiating the session has acquired less attention. In this document, we have addressed the SIP session setup delay problem. In the lab, we have built up a test bed for running several SIP session scenarios. Using different models for those scenarios, we have measured session setup delays for all used models. The analysis performed for each model showed that we could propose some models to be applied for SIP session setup delay components.

  • 18.
    Ahmed, Ashraf AwadElkarim Widaa
    et al.
    Blekinge Institute of Technology, School of Engineering.
    Makki, Ahmed Hamza Ibrahim
    Blekinge Institute of Technology, School of Engineering.
    Performance Evaluation of Uplink Multiple Access Techniques in LTE Mobile Communication System2010Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    The User Equipments (UE) nowadays are able to provide various internet applications and services that raise the demand for high speed data transfer and Quality of Service (QoS). Accordingly, next generation mobile communication systems driven by these demands are expected to provide higher data rates and better link quality compared to the existing systems. Orthogonal Frequency Division Multiple Access (OFDMA) and Single Carrier Frequency Division Multiple Access (SC-FDMA) are strong multiple access candidates for the uplink of the International Mobile Telecommunications-Advanced (IMT-Advanced). These multiple access techniques in combination with other promising technologies such as multi-hops transmission and Multiple-Input-Multiple-Output (MIMO) will be utilized to reach the targeted IMT-Advanced system performance. In this thesis, OFDMA and SC-FDMA are adopted and studied in the uplink of Long Term Evolution (LTE). Two transmission scenarios are considered, namely the single hop transmission and the relay assisted transmission (two hops). In addition, a hybrid multiple access technique that combines the advantages of OFDMA and SC-FDMA in term of low Peak-to-Average Power Ratio (PAPR) and better link performance (in terms of Symbol Error Rate (SER)) has been proposed in relay assisted transmission scenario. Simulation results show that the proposed hybrid technique achieves better end-to-end link performance in comparison to the pure SC-FDMA technique and maintains the same PAPR value in access link. In addition, a lower PAPR is achieved compared to OFDMA case, which is an important merit in the uplink transmission due to the UE’s power resources constraint (limited battery power).

  • 19.
    Ahmed, Ishtiaque
    Blekinge Institute of Technology, School of Engineering, Department of Telecommunication Systems.
    Study of the Local Backprojection Algorithm for Image Formation in Ultra Wideband Synthetic Aperture Radar2008Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    The purpose of this thesis project is to study and evaluate a UWB Synthetic Aperture Radar (SAR) data image formation algorithm, that was previously less familiar and, that has recently got much attention in this field. Certain properties of it made it acquire a status in radar signal processing branch. This is a fast time-domain algorithm named Local Backprojection (LBP). The LBP algorithm has been implemented for SAR image formation. The algorithm has been simulated in MATLAB using standard values of pertinent parameters. Later, an evaluation of the LBP algorithm has been performed and all the comments, estimation and judgment have been done on the basis of the resulting images. The LBP has also been compared with the basic time-domain algorithm Global Backprojection (GBP) with respect to the SAR images. The specialty of LBP algorithm is in its reduced computational load than in GBP. LBP is a two stage algorithm — it forms the beam first for a particular subimage and, in a later stage, forms the image of that subimage area. The signal data collected from the target is processed and backprojected locally for every subimage individually. This is the reason of naming it Local backprojection. After the formation of all subimages, these are arranged and combined coherently to form the full SAR image.

  • 20.
    Ahmed, Mamun
    Blekinge Institute of Technology, School of Engineering.
    Adaptive Sub band GSC Beam forming using Linear Microphone-Array for Noise Reduction/Speech Enhancement.2012Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    This project presents the description, design and the implementation of a 4-channel microphone array that is an adaptive sub-band generalized side lobe canceller (GSC) beam former uses for video conferencing, hands-free telephony etc, in a noisy environment for speech enhancement as well as noise suppression. The side lobe canceller evaluated with both Least Mean Square (LMS) and Normalized Least Mean Square (NLMS) adaptation. A testing structure is presented; which involves a linear 4-microphone array connected to collect the data. Tests were done using one target signal source and one noise source. In each microphone’s, data were collected via fractional time delay filtering then it is divided into sub-bands and applied GSC to each of the subsequent sub-bands. The overall Signal to Noise Ratio (SNR) improvement is determined from the main signal and noise input and output powers, with signal-only and noise-only as the input to the GSC. The NLMS algorithm significantly improves the speech quality with noise suppression levels up to 13 dB while LMS algorithm is giving up to 10 dB. All of the processing for this thesis is implemented on a computer using MATLAB and validated by considering different SNR measure under various types of blocking matrix, different step sizes, different noise locations and variable SNR with noise.

  • 21.
    Ahmed, Sabbir
    Blekinge Institute of Technology, School of Engineering, Department of Signal Processing.
    Performance of Multi-Channel Medium Access Control Protocol incorporating Opportunistic Cooperative Diversity over Rayleigh Fading Channel2006Independent thesis Advanced level (degree of Master (One Year))Student thesis
    Abstract [en]

    This thesis paper proposes a Medium Access Control (MAC) protocol for wireless networks, termed as CD-MMAC that utilizes multiple channels and incorporates opportunistic cooperative diversity dynamically to improve its performance. The IEEE 802.11b standard protocol allows the use of multiple channels available at the physical layer but its MAC protocol is designed only for a single channel. The proposed protocol utilizes multiple channels by using single interface and incorporates opportunistic cooperative diversity by using cross-layer MAC. The new protocol leverages the multi-rate capability of IEEE 802.11b and allows wireless nodes far away from destination node to transmit at a higher rate by using intermediate nodes as a relays. The protocol improves network throughput and packet delivery ratio significantly and reduces packet delay. The performance improvement is further evaluated by simulation and analysis.

  • 22. Ahmed, Sabbir
    et al.
    Casas, Christian Ibar
    Coso, Aitor del
    Mohammed, Abbas
    Performance of Multi-Channel MAC incorporating Opportunistic Cooperative Diversity2007Conference paper (Refereed)
  • 23.
    Aida, Horaniet
    et al.
    Blekinge Institute of Technology, School of Engineering, Department of Telecommunication Systems.
    Isabel, Llorente
    Blekinge Institute of Technology, School of Engineering, Department of Telecommunication Systems.
    Formation of High Resolution Images in SAR using GNSS2009Independent thesis Basic level (degree of Bachelor)Student thesis
    Abstract [en]

    The aim of this thesis is to investigate the possibility to form high resolution Synthetic Aperture Radar (SAR) images using the Global Navigation Satellite System (GNSS) Galileo, GPS and Glonas, In particular the thesis study the GPS signal and evaluate its properties for bistatic case. The report is based on the fact that Galileo and GPS are both positioning systems with similar characteristics. The difference is mainly that Galileo System uses a larger number of satellites and a different modulation scheme to improve the efficiency of the system, resulting in a better accuracy. On the topic of GNSS SAR, the report will be described with modes, resolution, geometry and algorithms. It is also explained the Space Surface Bi-static Radar and within two particular cases: parallel and non parallel paths

  • 24.
    Ajayi, Taiwo Seun
    Blekinge Institute of Technology, School of Engineering, Department of Telecommunication Systems.
    Mobile Satellite Communications: Channel Characterization and Simulation2007Independent thesis Advanced level (degree of Master (One Year))Student thesis
    Abstract [en]

    Abstract: The channel characterization of a mobile satellite communication which is an important and fast growing arm of wireless communication plays an important role in the transmission of information through a propagation medium from the transmitter to the receiver with minimum barest error rate putting into consideration the channel impairments of different geographical locations like urban, suburban, rural and hilly. The information transmitted from satellite to mobile terminals suffers amplitude attenuation and phase variation which is caused by multipath fading and signal shadowing effects of the environment. These channel impairments are commonly described by three fading phenomena which are Rayleigh fading, Racian fading and Log-normal fading which characterizes signal propagation in different environments. They are mixed in different proportions by different researchers to form a model to describe a particular channel. In the thesis, the general overview of mobile satellite is conducted including the classification of satellite by orbits, the channel impairments, the advantages of mobile satellite communication over terrestrial. Some of the major existing statistical models used in describing different type of channels are looked into and the best out of them which is Lutz model [6] is implemented. By simulating the Lutz model which described all possible type of environments into two states which represent non-shadowed or LOS and shadowed or NLOS conditions, shows that the BER is predominantly affected by shadowing factor.

  • 25.
    Akbar, Zeeshan
    et al.
    Blekinge Institute of Technology, School of Computing.
    Ali, Asar
    Blekinge Institute of Technology, School of Computing.
    Evaluation of AODV and DSR Routing Protocols of Wireless Sensor Networks for Monitoring Applications2009Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    Deployment of sensor networks are increasing either manually or randomly to monitor physical environments in different applications such as military, agriculture, medical transport, industry etc. In monitoring of physical environments, the most important application of wireless sensor network is monitoring of critical conditions. The most important in monitoring application like critical condition is the sensing of information during emergency state from the physical environment where the network of sensors is deployed. In order to respond within a fraction of seconds in case of critical conditions like explosions, fire and leaking of toxic gases, there must be a system which should be fast enough. A big challenge to sensor networks is a fast, reliable and fault tolerant channel during emergency conditions to sink (base station) that receives the events. The main focus of this thesis is to discuss and evaluate the performance of two different routing protocols like Ad hoc On Demand Distance Vector (AODV) and Dynamic Source Routing (DSR) for monitoring of critical conditions with the help of important metrics like throughput and end-to-end delay in different scenarios. On the basis of results derived from simulation a conclusion is drawn on the comparison between these two different routing protocols with parameters like end-to-end delay and throughput.

  • 26.
    Akber, Raza
    et al.
    Blekinge Institute of Technology, School of Engineering, Department of Telecommunication Systems.
    Raza, Syed Aqeel
    Blekinge Institute of Technology, School of Engineering, Department of Telecommunication Systems.
    Shafique, Usman
    Blekinge Institute of Technology, School of Engineering, Department of Telecommunication Systems.
    Performance Evaluation of WiMAX2009Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    The advancements in broadband and mobile communication has given many privileges to the subscribers for instance high speed data connectivity, voice and video applications in economical rates with good quality of services. WiMAX is an eminent technology that provides broadband and IP connectivity on “last mile” scenario. It offers both line of sight and non-line of sight wireless communication. Orthogonal frequency division multiple access is used by WiMAX on its physical layer. Orthogonal frequency division multiple access uses adaptive modulation technique on the physical layer of WiMAX and it uses the concept of cyclic prefix that adds additional bits at the transmitter end. The signal is transmitted through the channel and it is received at the receiver end. Then the receiver removes these additional bits in order to minimize the inter symbol interference, to improve the bit error rate and to reduce the power spectrum. In our research work, we investigated the physical layer performance on the basis of bit error rate, signal to noise ratio, power spectral density and error probability. These parameters are discussed in two different models. The first model is a simple OFDM communication model without the cyclic prefix, while the second model includes cyclic prefix.

  • 27.
    Akinwande, Gbenga Segun
    Blekinge Institute of Technology, School of Computing.
    Signaling Over Protocols Gateways in Next-Generation Networks2009Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    In this thesis, I examined various signalling both in wired and mobile networks, with more emphasis on SIGTRAN. The SIGTRAN is the protocol suite applicable in the current new generation and next-generation networks, most especially as it enables service provider to be able to interpolate both wireline and wireless services within the same architecture. This concept is an important component in today’s Triple-play communication, and hence this thesis has provided a broad view on Signalling and Protocol Gateways in Traditional and Next Generations Networks. Signal flow in a typical new generation network was examined by carrying out discrete event simulation of UMTS network using OPNET modeller 14.5. Through both Packet-Switching (PS) and Circuit-Switching (CS) signalling, I was able to examine the QoS on a UMTS. Precisely, I looked at throughput on UMTS network by implementing WFQ and MDRR scheduling schemes.

  • 28.
    Alahari, Yeshwanth
    et al.
    Blekinge Institute of Technology, School of Computing.
    Buddhiraja, Prashant
    Blekinge Institute of Technology, School of Computing.
    Analysis of packet loss and delay variation on QoE for H.264 andWebM/VP8 Codecs2011Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    The popularity of multimedia services over Internet has increased in the recent years. These services include Video on Demand (VoD) and mobile TV which are predominantly growing, and the user expectations towards the quality of videos are gradually increasing. Different video codec’s are used for encoding and decoding. Recently Google has introduced the VP8 codec which is an open source compression format. It is introduced to compete with existing popular codec namely H.264/AVC developed by ITU-T Video Coding Expert Group (VCEG), as by 2016 there will be a license fee for H.264. In this work we compare the performance of H.264/AVC and WebM/VP8 in an emulated environment. NetEm is used as an emulator to introduce delay/delay variation and packet loss. We have evaluated the user perception of impaired videos using Mean Opinion Score (MOS) by following the International Telecommunication Union (ITU) Recommendations Absolute Category Rating (ACR) and analyzed the results using statistical methods. It was found that both video codec’s exhibit similar performance in packet loss, But in case of delay variation H.264 codec shows better results when compared to WebM/VP8. Moreover along with the MOS ratings we also studied the effect of user feelings and online video watching experience impacts on their perception.

  • 29.
    Alam, Md. Jobayer
    et al.
    Blekinge Institute of Technology, School of Engineering.
    Sujan, Shaha Mohammed Goni Abed
    Blekinge Institute of Technology, School of Engineering.
    Low Complexity Channel Estimation for OFDM Systems Based on LS and MMSE Estimators’2010Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    In this paper we investigate the block-type pilot channel estimation for orthogonal frequency-division multiplexing (OFDM) systems. The estimation is based on the minimum mean square error (MMSE) estimator and the least square (LS) estimator. We derive the MMSE and LS estimators’ architecture and investigate their performances. We prove that the MMSE estimator performance is better but computational complexity is high, contrary the LS estimator has low complexity but poor performance. For reducing complexity we proposed two different solutions which are the Simplified Least Square (SLS) estimator and the modified MMSE estimator. We evaluate estimator’s performance on basis of mean square error and symbol error rate for 16 QAM systems. We also evaluate estimator’s computational complexity.

  • 30.
    Alam, Md. Khorshed
    Blekinge Institute of Technology, School of Engineering, Department of Telecommunication Systems.
    Linear Unequal Error Protection for Region of Interest Coded Images over Wireless Channels2005Independent thesis Advanced level (degree of Master (One Year))Student thesis
    Abstract [en]

    In this thesis, an unequal error protection scheme for transmitting JPEG2000 images over wireless channel is investigated. The rapid growth of wireless communication has resulted in a demand for robust transmission of compressed images over wireless networks. The challenge of robust transmission is to protect the compressed image data against the impairments of the radio channel, in such a way as to maximize the received image quality. However, for highly compressed images, it would be beneficial that regions of interest (ROI) are prioritized for interpretability. The thesis addresses this problem; investigating unequal error protection for transmitting JPEG2000 compressed images. More particularly, the results reported in this thesis provide guidance concerning the implementation of stronger error correction coding schemes (Golay code) for ROI and comparatively weaker coding (Hamming code) for non-ROI image spaces. Such unequal error protection can be utilized by the base station for transmitting JPEG2000-encoded images over next generation wireless networks.

  • 31.
    ALAM, MD. SHAMSER
    Blekinge Institute of Technology, School of Engineering.
    On sphere detection for OFDM based MIMO systems2010Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    The mobile wireless communication systems has been growing fast and continuously over the past two decades. Therefore, in order to fulfill the demand for this rapid growth, the standardization bodies along with wireless researchers and mobile operators around the world have been constantly working on new technical specifications.An important problem in modern communication is known as NP complete problem in the Maximum Likelihood (ML) detection of signals transmitting over Multiple Input Multiple Output channel of the OFDM transceiver system. Development of the Sphere Decoder (SD) as a result of the rapid advancement in signal processing techniques provides ML detection for MIMO channels at polynomial time complexity average case. There are weaknesses in the existing SDs. The sphere decoder performance is very sensitive for the most current proposals in order to choose the search radius parameter. At high spectral efficiencies SNR is low or as the problem dimension is high and the complexity coefficient can become very large too. Digital communications of detecting a vector of symbols has importance as, is encountered in several different applications. These symbols are as the finite alphabet and transmitted over a multiple-input multiple-output (MIMO) channel with Gaussian noise. There are no limitation to the detection of symbols spatially multiplexed over a multiple-antenna channel and the multi user detection problem. Efficient algorithms are considered for the detection problems and have recognized well. The algorithm of sphere decoder, orders has optimal performance considering the error probability and this has proved extremely efficient in terms of computational complexity for moderately sized problems in case of signal to noise ratio. At high SNR the algorithm has a polynomial average complexity and it is understood the algorithm has an exponential worst case complexity. The efficiency of the algorithm is ordered the exponential rate derivation of growth. Complexity is positive for the finite SNR and small in the high SNR. To achieve the sphere decoding solution applying Schnorr-Euchner by Maximum likelihood method , Depth-first Stack-based Sequential decoding is used. This thesis focuses on the receiver part of the transceiver system and takes a good look at the near optimal algorithm for sphere detection of a vector of symbols transmitted over MIMO channel. The analysis and algorithms are general in nature.

  • 32.
    Alam, Tahmid
    et al.
    Blekinge Institute of Technology, School of Engineering.
    Irshad, Sharmeen
    Blekinge Institute of Technology, School of Engineering.
    SW features in power systems for telecom equipment2013Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    This thesis report is a research effort with Ericsson’s devices and internal documents. In essence this thesis report contributes with a perspective to understand the power system of Radio Base Station and its features. The overall research aim is to understand the existing power system and its features and to propose new software and hardware features. A lot of investigations have been done with the Functional Specification and Requirement Specification documents for analysis of the present features. The main goal is to identify software features and their benefits to customer. After analysing the present features new features were proposed. For the proposal many steps were taken into consideration including cost and system information. Also some hardware changes have been required. With the new proposed features, the power system will perform better with different environments and also some of the proposals were improvements of the existing features. The proposed features are mostly focused on power saving and cost to benefit the customer.

  • 33.
    Aldalaty, Khalid
    Blekinge Institute of Technology, School of Engineering.
    Mobile IP handover delay reduction using seamless handover architecture2009Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    Seamless communication is becoming the main aspect for the next generation of the mobile and wireless networks. Roaming among multiple wireless access networks connected together through one IP core makes the mobility support for the internet is very critical and more important research topics nowadays. Mobile IP is one of the most successful solutions for the mobility support in the IP based networks, but it has poor performance in term of handover delay. Many improvements have been done to reduce the handover delay, which result in two new standards: the Hierarchical MIP (HMIP) and the Fast MIP (FMIP), but the delay still does not match the seamless handover requirements. Finally Seamless MIP (S-MIP) has been suggested by many work groups, which combine between an intelligent handover algorithm and a movement tracking scheme. In This thesis, we show the handover delay reduction approaches, specifically the Seamless Mobile IP. The thesis studies the effects of the S-MIP in the handover delay and the network performance as well. A simulation study takes place to compare between the standard MIP and the new suggested S-MIP protocol in term of handover delay, packet loss and bandwidth requirement. The thesis concludes with the analyzing of the simulation results, evaluating the S-MIP performance and finally gives some suggestions for the future work.

  • 34.
    Al-Delemi, Shahad
    Blekinge Institute of Technology, School of Management.
    Virtual Meeting's efficiency2011Student thesis
    Abstract [en]

    Idag använder många stora företag sig av distansarbete, där projekt utförs på olika orter/länder. För att få distansarbetet att vara så effektivt som möjligt så använder projektgrupperna sig av tekniska verktyg i sina möten som är utvecklade för att effektivisera dessa virtuella möten bland projektgruppen som befinner sig på olika orter/länder. Projektgruppen beteendet har också stor påverkan på hur effektiva dessa virtuella möten blir.

  • 35.
    Aleti, Mahesh
    et al.
    Blekinge Institute of Technology, Faculty of Engineering, Department of Applied Signal Processing.
    Syed, Rahamatulla
    Blekinge Institute of Technology, Faculty of Engineering, Department of Applied Signal Processing.
    Chennupati, Rajendra Prasad
    Blekinge Institute of Technology, Faculty of Engineering, Department of Applied Signal Processing.
    Fuzzy Based power control system Using ANFIS and MIMO-OFDM Techniques in Cognitive Radio Networks2014Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    Cognitive Radio technology is used for efficient utilization of the spectrum. There are two types of users, one is the Primary user (PU), and the second one is the Secondary user (SU). In those users, PU is having the license to use the spectrum. The SU does not have the license to use the spectrum. Cognitive Radio comprises of Spectrum sensing, Spectrum Management and Spectrum Mobility. In cognitive radio, optimal power control in spectrum sharing is main research issues. In the spectrum, sharing both PU and SU can access the spectrum simultaneously as long as there is no interference to PU’s of Quality of service (QOS). So we have to handle this interference to the PU and we have to improve the performance of the SU. For that power control is the main consternate to improve the performance of SU. In our thesis, we are divided into two parts, the first one is we used ANFIS (Adaptive Neuro Fuzzy Inference System) for optimizing power control in cognitive radio network Users (SU) by optimization of SNR & SINR at Primary User (PU) to maintain QOS of PU and improve the performance of SU and Channel capacity computation for various ISR tolerance levels at PU. In second part, we used implementation of MIMO (Multiple Input Multiple output)-OFDM (Orthogonal Frequency Division Multiplexing) transmission technique in CRN (Cognitive Radio networks) for it is use in emergency conditions where transmission requires reliability and high data rate. Then it is tested BER (Bit error rate) performance on MATLAB. Key words: Cognitive Radio, Power Control, the Fuzzy Interference System (FIS), ANFIS, “MIMO” (“Multiple Input Multiple Output”), “OFDM” (“Orthogonal Frequency Division Multiplexing”), AWGN, BER, SNR, Eb/N0

  • 36.
    Alfallah, Abdulaziz
    et al.
    Blekinge Institute of Technology, School of Computing.
    Alkaabey, Hieder
    Blekinge Institute of Technology, School of Computing.
    Study the Performance of the Use of SIP for Video Conferencing2011Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    The recent decades have witnessed enormous development in communication world; especially in internet technology that has played an important role in moving forward the human communications, with such development user demands better communication services such as video conferencing. Video conferencing becomes more popular nowadays since it can break the constraints on the communication ways of people who are probably exist in diverse geographical locations in real time. SIP is preferred to be used as signaling protocol for video conferencing, but still using SIP for video conferencing is affected by the delay which reduces the satisfaction of user as it decreases the QoS. This thesis work is aimed to study the performance of SIP signaling for video conferencing, and also describing the causes of the delay in SIP session establishment and termination. The literature review and the two simulations have been carried out in this thesis to examine the effect of specific parameters on the session setup delay. The first study is carried out by using ns-2 to simulate different transport protocols and study their effect on session setup delay. The second study is carried out by using SIPp to achieve two objects. The first object is to study the relationship between number of simultaneous calls on both the session setup delay and call release delay, while the second object is to verify the result of changing transport modes of transport protocol for both session setup delay and call release delay. The results obtained from first simulation showed that utilizing UDP as transport protocol will return less session setup delay than TCP and SCTP. The first objective of the second simulation results clarify the relationship between number of simultaneous calls on both the session setup delay and call release delay which was directly proportional; on the other hand the second object showed that by using UDP in mono socket mode has less session setup delay and call release delay.

  • 37.
    Ali, Hassan
    et al.
    Blekinge Institute of Technology, School of Computing.
    Yazdani, Talha Moiz
    Blekinge Institute of Technology, School of Computing.
    Measurement Tools for IP Multimedia Subsystems (IMS)2009Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    is indeed a milestone. Next Generation Network (NGN) is an IP network which facilitates researcher to achieve this milestone. IP Multimedia Sub-system (IMS) makes possible to deliver IP multimedia services to users. IMS uses Session Initiation Protocol (SIP) as a signalling protocol. Since IMS involves lot of signalling between IMS entities and other network elements, accordingly the signalling must guarantee quality of service. Test beds and measuring tools help us to perform various tests according to our need. These tests should be carried in early stages of development with designer in structured way according to well defined process and methods. Initially this thesis aims to identify useful tools for IMS which can develop an appropriate IMS service creation environment. The basic task involves decoding of SIP message and to gather response time information. Finally to provide a proposal which tool is suitable for measuring signalling protocol regarding performance, exportability and hardware requirements.

  • 38.
    Ali, Hazrat
    Blekinge Institute of Technology, School of Computing.
    A Performance Evaluation of RPL in Contiki2012Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    A Wireless Sensor Network is formed of several small devices encompassing the capability of sensing a physical characteristic and sending it hop by hop to a central node via low power and short range transceivers. The Sensor network lifetime strongly depends on the routing protocol in use. Routing protocol is responsible for forwarding the traffic and making routing decisions. If the routing decisions made are not intelligent, more re-transmissions will occur across the network which consumes limited resources of the wireless sensor network like energy, bandwidth and processing. Therefore a careful and extensive performance analysis is needed for the routing protocols in use by any wireless sensor network. In this study we investigate Objective Functions and the most influential parameters on Routing Protocol for Low power and Lossy Network (RPL) performance in Contiki (WSN OS) and then evaluate RPL performance in terms of Energy, Latency, Packet Delivery Ratio, Control overhead, and Convergence Time for the network. We have carried out extensive simulations yielding a detailed analysis of different RPL parameters with respect to the five performance metrics. The study provides an insight into the different RPL settings suitable for different application areas. Experimental results show ETX is a better objective, and that ContikiRPL provides very efficient network Convergence (14s), Control traffic overhead (1300 packets), Energy consumption (1.5% radio on time), Latency (0.5s), and Packet Delivery Ratio (98%) in our sample RPL simulation of one hour with 80 nodes, after careful configuration of DIO interval minimum/doublings, Radio duty cycling, and Frequency of application messages.

  • 39.
    Ali, Mohsin
    et al.
    Blekinge Institute of Technology, School of Engineering.
    Nasir, Muhammad Jamal
    Blekinge Institute of Technology, School of Engineering.
    Echo Cancellation using PMSAF and Compare the performance with NLMS and improved PNLMS under different Impulse responses2013Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    In the field of signal processing adaptive filtering is a major subject which has vast applications in speech processing e.g. speech coding, speech enhancement, echo cancellation and interference. Echo is the major problem in the communication systems. There are two major types of echoes hybrid and acoustic echoes. In order to remove these echoes the most important method for removing these echoes is through cancellation. Adaptive filters are used to estimate the replication of echoes and then subtracted from the infected signal. . We introduced subband filters to improve the performance of adaptive filter (time domain). Due to small adaptive filters in the subband filter banks, we can improve the reduction of complexity, computational and convergence level as compared with others. The major goal of this thesis is to present the echo cancellation using the multiband subband adaptive filtering and also compare the performance with NLMS and Improved PNLMS using different impulse responses. PMSAF algorithm behaves continuously better convergense rate with excitation signal (colored noise and speech signal) for both impulse responses (sparse and dispersive) as compared with IPNLMS and NLMS algorithms.

  • 40.
    Ali, Muhammad Usman
    Blekinge Institute of Technology, School of Computing.
    Cloud Computing as a Tool to Secure and Manage Information Flow in Swedish Armed Forces Networks2012Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    In the last few years cloud computing has created much hype in the IT world. It has provided new strategies to cut down costs and provide better utilization of resources. Apart from all drawbacks, the cloud infrastructure has been long discussed for its vulnerabilities and security issues. There is a long list of service providers and clients, who have implemented different service structures using cloud infrastructure. Despite of all these efforts many organizations especially with higher security concerns have doubts about the data privacy or theft protection in cloud. This thesis aims to encourage Swedish Armed Forces (SWAF) networks to move to cloud infrastructures as this is the technology that will make a huge difference and revolutionize the service delivery models in the IT world. Organizations avoiding it would lag behind but at the same time organizations should consider to adapt a cloud strategy most reliable and compatible with their requirements. This document provides an insight on different technologies and tools implemented specifically for monitoring and security in cloud. Much emphasize is given on virtualization technology because cloud computing highly relies on it. Amazon EC2 cloud is analyzed from security point of view. An intensive survey has also been conducted to understand the market trends and people’s perception about cloud implementation, security threats, cost savings and reliability of different services provided.

  • 41.
    Ali, Sajjad
    et al.
    Blekinge Institute of Technology, School of Computing.
    Ali, Asad
    Blekinge Institute of Technology, School of Computing.
    Performance Analysis of AODV, DSR and OLSR in MANET2010Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    A mobile ad hoc network (MANET) consists of mobile wireless nodes. The communication between these mobile nodes is carried out without any centralized control. MANET is a self organized and self configurable network where the mobile nodes move arbitrarily. The mobile nodes can receive and forward packets as a router. Routing is a critical issue in MANET and hence the focus of this thesis along with the performance analysis of routing protocols. We compared three routing protocols i.e. AODV, DSR and OLSR. Our simulation tool will be OPNET modeler. The performance of these routing protocols is analyzed by three metrics: delay, network load and throughput. All the three routing protocols are explained in a deep way with metrics. The comparison analysis will be carrying out about these protocols and in the last the conclusion will be presented, that which routing protocol is the best one for mobile ad hoc networks.

  • 42.
    Ali, Wajahat
    et al.
    Blekinge Institute of Technology, School of Computing.
    Muhammad, Asad
    Blekinge Institute of Technology, School of Computing.
    Response Time Effects on Quality of Security Experience2012Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    The recent decade has witnessed an enormous development in internet technology worldwide. Initially internet was designed for applications such as Electronic Mail and File Transfer. With technology evolving and becoming popular, people use internet for e-banking, e-shopping, social networking, e-gaming, voice and a lot of other applications. Most of the internet traffic is generated by activities of end users, when they request a specific webpage or web based application. The high demand for internet applications has driven service operators to provide reliable services to the end user and user satisfaction has now become a major challenge. Quality of Service is a measure of the performance of a particular service. Quality of Experience is a subjective measure of user’s perception of the overall performance of network. The high demand for internet usage in everyday life has got people concerned about security of information over web pages that require authentication. User perceived Quality of Security Experience depends on Quality of Experience and Response Time for web page authentication. Different factors such as jitter, packet loss, delay, network speed, supply chains and the type of security algorithm play a vital role in the response time for authentication. In this work we have tried to do qualitative and quantitative analysis of user perceived security and Quality of Experience with increasing and decreasing Response Times towards a web page authentication. We have tried to derive a relationship between Quality of Experience of security and Response Time.

  • 43.
    Alibabaei, Navid
    Blekinge Institute of Technology, Faculty of Computing, Department of Communication Systems.
    Wireless Mesh Networks: a comparative study of Ad-Hoc routing protocols toward more efficient routing2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Each day, the dream of seamless networking and connectivity everywhere is getting closer to become a reality. In this regard, mobile Ad-Hoc networks (MANETs) have been a hot topic in the last decade; but the amount of MANET usage nowadays confines to a tiny percentage of all our network connectivity in our everyday life, which connectivity through infrastructured networks has the major share. On the other hand, we know that future of networking belongs to Ad-Hocing , so for now we try to give our everyday infrastructure network a taste of Ad-Hocing ability; these types of networks are called Wireless Mesh Networks (WMN) and routing features play a vital role in their functionality. In this thesis we examine the functionality of 3 Ad-Hoc routing protocols known as AODV, OLSR and GRP using simulation method in OPNET17.5. For this goal we set up 4 different scenarios to examine the performance of these routing protocols; these scenarios vary from each other in amount of nodes, background traffic and mobility of the nodes. Performance measurements of these protocols are done by network throughput, end-end delay of the transmitted packets and packet loss ratio as our performance metrics. After the simulation run and gathering the results we study them in a comparative view, first based on each scenario and then based on each protocol. For conclusion, as former studies suggest AODV, OLSR and DRP are among the best routing protocols for WMNs, so in this research we don’t introduce the best RP based on the obtained functionality results, instead we discuss the network conditions that each of these protocols show their best functionality in them and suggest the best routing mechanism for different networks based on the analysis from the former part.  

  • 44.
    AL-MAMUN, ABDULLAH
    et al.
    Blekinge Institute of Technology, School of Engineering.
    ULLAH, MOHAMMAD RAFIQ
    Blekinge Institute of Technology, School of Engineering.
    Cognitive Radio for Short Range Systems based on Ultra-Wideband2011Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    Cognitive Radio (CR) has been proposed as a promising and effective technology to improve radio spectrum utilization. It can change its transmitter parameters depending on the environment in which it operate based on interaction. In CR, a number of different methods of spectrum sensing are used to identify the presence of signal transmission. Among them, the multitaper method (MTM), has been investigated in this thesis paper at the same time with other sensing methods, recently seems to be the best choice for spectrum sensing CR because of its accurate identification and estimation, quick computation, and regularization. This thesis paper is examining how CR can be utilized in short range systems based on Ultra-Wideband (UWB). UWB is a promising technology in wireless communication use for high speed data transmission with low power utilization or long distance localization in both military, radar, sensor, data collection, tracking or commercial application. UWB has the ability to move between very low data rate or very high data rate, short range distance or long range distance applications. Impulse radio UWB (IR-UWB) shows some impressive characteristics in short-range communication systems with varieties of throughput option including high data rates. The strong synergy between the aims of CR and features of IR-UWB has been shown in this thesis. Our key objective is to understand how CR can be applied to UWB systems.

  • 45. Al-Mamun, Abdullah
    et al.
    Ullah, Mohammad Rafiq
    Multitaper spectrum: A promising method in spectrum sensing cognitive radio2010Conference paper (Refereed)
    Abstract [en]

    Cognitive radio (CR) has been proposed as a promising and effective technology to improve radio spectrum utilization. The primary objective of the CR is to handle the non-interference rules with any primary users (PUs). Highly sensitive and optimal spectrum sensing detectors are required in order to avoid harmful interference to PUs. Multitaper spectrum seems to be the most appealing one for spectrum sensing CR because of its accurate identification and estimation and low computational complexity. Mulitaper uses small set of tapers and multiple orthogonal prototype filters to reduce the variance. The Fourier transform of a Slepian sequence, originally known as discrete prolate spheroidal sequences (DPSS), gives maximum energy density inside a given bandwidth and less spectral leakage with better specifications has been investigated in this paper and shows that no other window in signal processing can satisfy this property

  • 46. Al-Qahtani, Fawaz S.
    et al.
    Duong, Quang Trung
    Gurung, Arun K.
    Bao, Vo Nguyen Quoc
    Selection Decode-and-Forward Relay Networks with Rectangular QAM in Nakagami-m Fading Channels2010Conference paper (Refereed)
    Abstract [en]

    In this paper, we investigate the average symbol error probability (SEP) of fixed decode-and-forward relay networks over independent but not identically distributed Nakagami-m fading channels. We have derived closed form expression of SEP for general rectangular quadrature amplitude modulation (QAM) under relay selection scheme where only the best relay forwards message from the source to the destination. The expressions are in terms of hypergeometric series which can be efficiently numerically evaluated. The numerical results are validated with Monte-Carlo simulations.

  • 47. Al-Qahtani, Fawaz S.
    et al.
    Duong, Quang Trung
    Blekinge Institute of Technology, School of Computing.
    Zhong, Caijun
    Qaraqe, Khaild A.
    Alnuweiri, Hussein
    Performance Analysis of Dual-Hop AF Systems with Interference in Nakagami-m Fading Channels2011In: IEEE Signal Processing Letters, ISSN 1070-9908, Vol. 18, no 8, p. 454-457Article in journal (Refereed)
    Abstract [en]

    In this paper, we investigate the performance of dual-hop channel state information-assisted amplify-and-forward relaying systems over Nakagami-m fading channels in the presence of multiple interferers at the relay. Assuming integer fading parameter m, we derive closed-form expressions for the exact outage probability and accurate approximation for symbol error rate of the system. Furthermore, we look into the asymptotical high signal to noise ratio regime, and characterize the diversity order achieved by the system. All the analytical results are validated via Monte Carlo simulations.

  • 48.
    Aluguri, Tarun
    Blekinge Institute of Technology, Faculty of Computing, Department of Communication Systems.
    Performance Evaluation of OpenStack Deployment Tools2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Cloud computing enables on-demand access to a shared pool of computing resources, that can beeasily provisioned, configured and released with minimal management cost and effort. OpenStack isan open source cloud management platform aimed at providing private or public IaaS cloud onstandard hardware. Since, deploying OpenStack manually is tedious and time-consuming, there are several tools that automate the deployment of OpenStack. Usually, cloud admins choose a tool basedon its level of automation, ease of use or interoperability with existing tools used by them. However,another desired factor while choosing a deployment tool is its deployment speed. Cloud admins cannot select based on this factor since, there is no previous work on the comparison of deploymenttools based on deployment time. This thesis aims to address this issue.

    The main aim of the thesis is to evaluate the performance of OpenStack deployment tools with respectto operating system provisioning and OpenStack deployment time, on physical servers. Furthermore,the effect of varying number of nodes, OpenStack architecture deployed and resources (cores andRAM) provided to deployment node on provisioning and deployment times, is also analyzed. Also,the tools classified based on stages of deployment and method of deploying OpenStack services. In this thesis we evaluate the performance of MAAS, Foreman, Mirantis Fuel and Canonical Autopilot.

    The performance of the tools is measured via experimental research method. Operating system provisioning time and OpenStack deployment times are measured while varying the number of nodes/OpenStack architecture and resources provided to deployment node i.e. cores and RAM.

    Results show that provisioning time of MAAS is less than Mirantis Fuel, which is less than Foreman.Furthermore, for all 3 tools as number of nodes increases provisioning time increases. However, the amount of increase is lowest for MAAS than Mirantis Fuel and Foreman. Similarly, results for baremetal OpenStack deployment time show that, Canonical Autopilot outperforms Mirantis Fuel by asignificant difference for all OpenStack scenarios considered. Furthermore, as number of nodes in an OpenStack scenario increases, the deployment time for both the tools increases.

    From the research, it is concluded that MAAS and Canonical Autopilot perform better as provisioningand bare metal OpenStack deployment tool respectively, than other tools that have been analyzed.Furthermore, from the analysis it can be concluded that increase in number of nodes/ OpenStackarchitecture, leads to an increase in both provisioning time and OpenStack deployment time for all the tools.

  • 49.
    Amjad, Shoaib
    et al.
    Blekinge Institute of Technology, Faculty of Computing, Department of Computer Science and Engineering.
    Malhi, Rohail Khan
    Blekinge Institute of Technology, Faculty of Computing, Department of Computer Science and Engineering.
    Burhan, Muhammad
    Blekinge Institute of Technology, Faculty of Computing, Department of Computer Science and Engineering.
    DIFFERENTIAL CODE SHIFTED REFERENCE IMPULSE-BASED COOPERATIVE UWB COMMUNICATION SYSTEM2013Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    Cooperative Impulse Response – Ultra Wideband (IR-UWB) communication is a radio technology very popular for short range communication systems as it enables single-antenna mobiles in a multi-user environment to share their antennas by creating virtual MIMO to achieve transmit diversity. In order to improve the cooperative IR-UWB system performance, we are going to use Differential Code Shifted Reference (DCSR). The simulations are used to compute Bit Error Rate (BER) of DCSR in cooperative IR-UWB system using different numbers of Decode and Forward relays while changing the distance between the source node and destination nodes. The results suggest that when compared to Code Shifted Reference (CSR) cooperative IR-UWB communication system; the DCSR cooperative IR-UWB communication system performs better in terms of BER, power efficiency and channel capacity. The simulations are performed for both non-line of sight (N-LOS) and line of sight (LOS) conditions and the results confirm that system has better performance under LOS channel environment. The simulation results also show that performance improves as we increase the number of relay nodes to a sufficiently large number.

  • 50.
    AMUJALA, NARAYANA KAILASH
    et al.
    Blekinge Institute of Technology, Faculty of Computing, Department of Communication Systems.
    SANKI, JOHN KENNEDY
    Blekinge Institute of Technology, Faculty of Computing, Department of Communication Systems.
    Video Quality of Experience through Emulated Mobile Channels2014Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    Over the past few years, Internet traffic took a ramp increase. Of which, most of the traffic is video traffic. With the latest Cisco forecast it is estimated that, by 2017 online video will be highly adopted service with large customer base. As the networks are being increasingly ubiquitous, applications are turning equally intelligent. A typical video communication chain involves transmission of encoded raw video frames with subsequent decoding at the receiver side. One such intelligent codec that is gaining large research attention is H.264/SVC, which can adapt dynamically to the end device configurations and network conditions. With such a bandwidth hungry, video communications running over lossy mobile networks, its extremely important to quantify the end user acceptability. This work primarily investigates the problems at player user interface level compared to the physical layer disturbances. We have chosen Inter frame time at the Application layer level to quantify the user experience (player UI) for varying lower layer metrics like noise and link power with nice demonstrator telling cases. The results show that extreme noise and low link level settings have adverse effect on user experience in temporal dimension. The video are effected with frequent jumps and freezes.

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