National Telecommunication Institute NTI

Cairo, Egypt

National Telecommunication Institute NTI

Cairo, Egypt
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Omran H.,German University in Cairo | Kotb H.E.,National Telecommunication Institute NTI | Khalil D.,Ain Shams University
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2017

In this paper we present a novel dual wavelength SOA based fiber ring laser. The ring laser combines the effect of SOA gain starving at the edge of the gain spectrum and the polarization state in the PM fiber ring to generate a dual wavelength laser at 1452.7 nm and 1454.5 nm with single mode operation verified. With the proposed technique, single wavelength single mode laser operation can be easily obtained by adjusting the SOA pumping current and the ring polarization state. © 2017 SPIE.

Ibn-Khedher H.,Orange S.A. | Abd-Elrahman E.,National Telecommunication Institute NTI | Kamal A.E.,Iowa State University | Afifi H.,Orange S.A.
Computer Networks | Year: 2017

Cloud computing and Network Function Virtualization (NFV) use cases proposed by ETSI can improve network caching when an adequate optimization algorithm is used. A cache placement algorithm is proposed based on these virtualization tools. Moreover, a cache placement protocol is presented to support the cache migration. Optimal cache and Virtual Machine (VM) placement and migration, and optimal routing based on several new constraints such as system load, network infrastructure, user satisfaction and migration cost is designed. Extensive evaluations and comparison to state of the art techniques are carried out. The results show that our cache techniques outperform other solutions and give better satisfaction to the three constituents: users, network operators and content providers. © 2017 Elsevier B.V.

Saafan A.M.,National Telecommunication Institute NTI | El-Badawy H.M.,National Telecommunication Institute NTI
National Radio Science Conference, NRSC, Proceedings | Year: 2017

Cognitive Radio (CR) is an emerging technology which enables efficient utilization of the spectrum. As such, it has created great interests in industrial and research fields. Since CR users are vulnerable to malicious attacks, security countermeasures are important for the successful deployment of CR networks in the future. This paper focuses on defending against the jamming attack. The major contribution in this paper is to create a test-bed model for evaluating the spectrum access and co-existence of primary and secondary users, study their performance analysis in presence of a jammer in the environment and how to deal with it in the CR system. In this paper, a spectrum monitoring technique with Software Defined Radio (SDR) is deployed, the setup of the prototype based on Universal Software Radio Peripheral (USRP) with LabVIEW is designed and implemented, the spectrum of 900 MHz band has been investigated as a proof of concept. © 2017 IEEE.

Sayed H.A.,National Telecommunication Institute NTI | Ibrahim A.W.,National Telecommunication Institute NTI | Ebrahim H.,National Telecommunication Institute NTI
2016 2nd IEEE International Conference on Computer and Communications, ICCC 2016 - Proceedings | Year: 2017

The IP Multimedia Subsystem (IMS) is an architectural framework suitable for Fixed Mobile Convergence (FMC), where users can access multimedia services ubiquitously from any wireless or wired device. Supporting the user mobility and seamless handover across different heterogeneous access networks in IMS environments represents a challenge. The process involves session re-establishment, incurs long signaling delay, and may result in session interruption. In this paper, we propose a new signaling technique to manage session continuity of IMS services, particularly the seamless transfer of multimedia sessions across different heterogeneous access networks. The proposal relies on using existing SIP requests and does not require the addition of new network entities as opposed to the existing approaches. The proposed technique is simulated using OPNET Modeler for different heterogeneous networks including WLAN/WiMAX/LTE and the performance is evaluated for different users mobility speeds. © 2016 IEEE.

El-Hennawy H.M.,Ain Shams University | Gomaa H.H.,Ain Shams University | Amin A.S.,National Telecommunication Institute NTI
ICT 2010: 2010 17th International Conference on Telecommunications | Year: 2010

Internet Protocol version 6 (IPv6) is a new protocol that has been defined to ultimately replace IPv4. IPv6 solves the problem imposed by the limited 32-bit address field in IPv4. However the definition of the new protocol results in longer header size, which affects services that used to be transmitted over IP especially real-time services such as voice. As IP network is no longer confined to the wired domain and is being extended over wireless networks. The IEEE 802.16-based WiMAX (World Wide Interoperability of Microwave Access) promises to be one of the wireless access technologies capable of supporting very high bandwidth applications. In this paper, using the simulation results obtained by NS2, we demonstrate the effectiveness of transmitting voice traffic over IPv6 convergence sublayer of WiMAX mesh network and compare it with the quality in case of applying current header compression techniques, Robust Header Compression (ROHC) and Payload Header Suppression (PHS), and a new proposed modification to the PHS technique. We prove that using our proposed technique we improve the current PHS technique and approach the same performance of ROHC technique. © 2009 IEEE.

Said A.M.,National Telecommunication Institute NTI | Ibrahim A.W.,National Telecommunication Institute NTI | Soua A.,Telcom SudParis | Afifi H.,Telcom SudParis
Proceedings - International Conference on Advanced Information Networking and Applications, AINA | Year: 2013

Sensor networks suffer from limited capabilities such as bandwidth, low processing power, and memory size. There is therefore a need for protocols that deliver sensor data in an energy-efficient way to the sink. One of those techniques, it gathers sensors' data in a small size packet suitable for transmission. In this paper, we propose a new Effective Data Aggregation Protocol (DAP) to reduce the energy consumption in Wireless Sensor Networks (WSNs), which prolongs the network lifetime. This work uses in-network aggregation approach to distribute the processing all over the aggregation path to avoid unbalanced power consumption on specific nodes until they run out. Simulation results prove that DAP, compared to other protocols, achieves more data aggregation percentage and less power consumption for a one data harvesting round. © 2013 IEEE.

Said A.M.,National Telecommunication Institute NTI | Ibrahim A.W.,National Telecommunication Institute NTI
2012 IEEE 14th International Conference on e-Health Networking, Applications and Services, Healthcom 2012 | Year: 2012

Sensor Networks are considered the heart of a wide range of applications. e-Health is one of those applications. This paper proposes a new network and Context Awareness service architecture for e-Health services. The proposal integrates the Ubiquitous Sensor Network (USN) with the IP Multimedia Subsystem (IMS)-based Next Generation Network (NGN). It provides a detailed signaling model for different healthcare scenarios based on SIP. The proposal involves modifications made to SIP to match the new e-Health features provided. © 2012 IEEE.

Eltaweel S.G.,National Telecommunication Institute NTI
2013 9th International Computer Engineering Conference: Today Information Society What's Next?, ICENCO 2013 | Year: 2013

In this paper, we have a mixture of two added images and it is required to separate the two image sources from the combined one after receiving the combined image and one of the two source images. The Discrete Wavelet Transform (DWT) is applied on the combined image. Also, it is applied on the corrupted and received image source. The high frequency components of the combined image and the image source are correlated. The result of correlation is used in classifying the pixel whether belongs to image source or zero. The experiment is applied on the other image source and the combined image. The performance is measured and compared to a recent paper in the same topic and the proposed method is proved to have better results than the results of the recent paper. In the recent paper, the color mixture is not considered, it is considered in our work and gave very good results. © 2013 IEEE.

Eltaweel S.G.,National Telecommunication Institute NTI
ICENCO'2011 - 2011 7th International Computer Engineering Conference: Today Information Society What's Next? | Year: 2012

In this paper a new technique is introduced to hide nine images in a color image. The color image has size four as the watermark size. In each of the color image components three images are hidden. Each color component is decomposed by a Discrete Wavelet Transform (DWT) into four components. Three of four components are used to hide the three images. The hiding operation starts with taking the Discrete Cosine Transform (DCT) for the watermark and the result is multiplied by a factor and added to a component of the three components which result from the DWT decomposition. The Inverse DWT (IDWT) is applied to reconstruct the red, green and blue components. Finally, the result is the reconstruction from the main components. The extraction process is considered in the theory of statistical signal processing as a correlation receiver. The correlation is calculated to decide each pixel is a watermark pixel or not. Different types of images are used as watermarks. The results show the robustness of the technique, the SNR obtained is at least 25 dB. © 2011 IEEE.

El Zorkany M.,National Telecommunication Institute NTI
Advances in Intelligent Systems and Computing | Year: 2014

Image and video transmissions require particularly large bandwidth and storage space. Image compression technology is therefore essential to overcome these problems. Practically efficient compression systems based on hybrid coding which combines the advantages of different methods of image coding have also being developed over the years. In this paper, different hybrid approaches to image compression are discussed. Hybrid coding of images, in this research, deals with combining three approaches to enhance the individual methods and achieve better quality reconstructed images with higher compression ratio. In this paper A new Hybrid neural-network, vector quantization and discrete cosine transform compression method is presented. This scheme combines the high compression ratio of Neural network (NN) and Vector Quantization (VQ) with the good energy-compaction property of Discrete Cosine Transform(DCT). In order to increase the compression ratio while preserving decent reconstructed image quality, Image is compressed using Neural Network, then take the hidden layer outputs as input to re-compress it using vector quantization (VQ), while DCT was used the code books block. Simulation results show the effectiveness of the proposed method. The performance of this method is compared with the available jpeg compression technique over a large number of images, showing good performance. © Springer International Publishing Switzerland 2014.

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