Système et gestion des télécommunications

Image denoising plays an important role in digital image processing. There are many ways to denoise an image, which including gradient-based, sparse representation-based, non-local self-similarity-based, Gradient Histogram Preservative (GHP) algorithm. By using GHP algorithms noise can be removed, but it degrads the visual quality of an original image and also execution time to generate the denoised image is large. To avoid this problem, in this paper, we propose a Discrete Wavelet Transform (DWT), Stationary wavelet transform (SWT) and Singular Value Decomposition (SVD) method. This method is developed to enhance brightness and resolution while removing noise and execution time should be reduced. Our experimental results demonstrate that the proposed Discrete Wavelet Transform (DWT), Stationary wavelet transform (SWT) and Singular Value Decomposition (SVD) method can well preserve the texture appearance in the denoised images and improve the resolution of denoised image and execution time should be reduced.

Self-interference (SI) occurs if the transmission is through a multipath channel. The channel distorts helps to break the orthogonality between the spreading codes. In addition, the amplitude of linear precoded orthogonal frequency division multiplexing (LP-OFDM). LP-OFDM signals have strong fluctuations. Thus, it is necessary to seek or to minimize these two problems by the reduction of term SI and the amplitude of fluctuations Peak-to-Average Power Ratio (PAPR). In this paper a new method of allocation of spreading code has proposed. It consists of a double selection of spreading codes minimizing joint SI and PAPR. Simulation results show that the LP-OFDM system is optimized by this proposal compared to the conventional solution where the systems don’t operate in full load.

Code-Hopping Multiple Access (CHMA) has been an emerging Multiple Access (MA) technology which offers excellent performance in multipath fading channels with Orthogonal Complementary Codes (OCC). Orthogonality among users is not preserved in multipath channel conditions using the existing orthogonal and semi-orthogonal codes. Further, Multiple Access Interference (MAI) and Multipath Interference (MPI) destroy orthogonality of the code set which in turn increases the error rate during the detection process. An OCC set possesses both ideal auto-correlation and ideal cross-correlation properties for any two codes in the same set. Here, we employ OCC for spreading and prove that the performance of OCC is superior to those of Gold codes in multipath channels where orthogonality does not hold. The error probability expressions for Rayleigh and Nakagami-m fading channels using Maximal Ratio Combining (MRC) are derived for CHMA system using OCCs. We then evaluate the system performance using the proposed technique and show that the new scheme is much better compared to traditional CHMA schemes.

MANET is a type of wireless network without a fixed topology and consists of set of self-organized nodes. The nodes are randomly, frequently and unpredictably mobile. The inherent features make them an ideal choice in military and civilian communication applications. Major performance constraint of these types of networks comes from security attacks due to the dynamic topology and lack of centralized monitoring authority. Both passive and active attacks adversely affect the normal functionality of the network. Passive attackers monitor the network traffic and nodes in the networks. Active attacks like Blackhole attackers can drop packets partially or completely from the network. Secure routing protocol can conceal the identities and locations of route, source and destination to provide security and privacy from intruder’s attacks. So in this paper, a route selection method is introduced for MANET which improves the security features for source, destination and route against passive attacks and specified active attacks. The developed method dynamically partitions the entire communication area in to different zones and randomly chooses a position from the divided zones as the temporary destination. The node which is very close to the position is selected as the random forwarder node and data is transmitted through random forwarder node using GPSR. The proposed method provide both identity and location anonymity to nodes. Methods are also proposed for avoiding the timing attacks. Position of active attacker like Blackhole attackers in the route are obtained and eliminated by using Hom omorphic Message Authentication method.

Challenging times for Chief Marketing Officers (CMOs) in Telecommunication space: The telecom industry is a fast moving, emerging, evolving and converging space with rapidly changing business scenarios and technology variations. This poses a formidable challenge and also an opportunity to the CMOs. Churn rates reaching up to 8-10% or further are experienced by most telecom operators across the globe. Although large investments are made to bridge the gap, but CMOs have been forced to admit that there is no unanimous solution. ARPU on a steady decline: With greater maturity in the marketplace, operators attract more marginal customers leading to inevitable squeezing of ARPU and margins. Also, new technology alternatives such as VoIP are further eroding traditional profit centres for most of the operators. Multiple channels to the customer: Telecom operators have a distinct advantage - telecommunication companies control the media as well as the message. Mobile operators in particular have access to the new billboard i.e. the mobile phone. On the downside, as increase in the choice of channels to the customer also means more sophistication in execution is required to choose the most appropriate channel to each customer.

Voice over long-term evolution is stated as VoLTE. It is youngest evolution in IP technology and evolving very fast. The main drivers for VoLTE have been the fact that LTE is a packet only architecture and LTE has no inbuilt voice+SMS service engine. A solution for Voice over LTE needed as soon as mobile terminals start to use the LTE access. VoLTE provides various advantages for operator as well as end users by improving spectral and network efficiency. Deployments of VoLTE services are increasing at very fast rate and it requires number of troubleshooting and optimizations methods to improve the high definition voice quality of service. This paper presents the various aspects used to optimize the VoLTE network.

This article intends to make a proposal to implement the organizational model applied to digital cities. It uses a model proposed by the author which was used as content in four of his published books, covering the main areas of the administration in a systemic way. Allows the study of areas composing the management of a city, separately assessing their characteristics, composition and interconnection. After this study the Manager will be able to assess the entire system and seek to optimize the application in a systemic manner. His contribution is to allow a breakthrough in the study of the integration between the parts making up the functioning of the city.

6LoWPAN was introduced by the IETF as a standard protocol to interconnect tiny and constrained devices across IPv6 clouds. 6LoWPAN supports a QoS feature based on two priority bits. So far, little interest has been granted and this QoS feature and there are no implementations of such feature in real networks. In this paper, we evaluate the effectiveness of these priority bits in various scenarios. We show that under very heavy or very low network load, these bits have a limited effect on the delay.

Presently, Multimedia services such as video-streaming applications e.g. Live streaming, video lecture are more demanded and service over wireless network (802.11e) are more used. Hence, it is necessary to provide end-to-end Quality of service (QoS) over wireless network, as it poses a challenging problem due to the transient structure of wireless networks. The weakness of Dynamic source routing with wireless system has been analyzed and work has been done to improve the Quality of service parameters such as throughput etc. MMDSR (Multipath Multimedia Dynamic Source Routing) is a multipath routing protocol DSR-based if merged with a cross-layer framework can provide enhanced QoS for multiple sources of video over IEEE 802.11e wireless networks.