Badr Benmammar

A Survey on Dynamic Spectrum Access Techniques in Cognitive Radio Networks

A Mobile Ad hoc NETwork (MANET) is a wireless communication network with minimum physical infrastructure with diverse communication applications. Mobility and Multihopping are the main characteristics of MANET. Multipath routing protocols establish multiple routes between nodes. The construction of multiple routes should be done with minimum overhead and bandwidth consumption. The purpose of this article is to analyze the characteristics and functionality of various multipath routing protocols and to do the performance comparison between these multipath routing protocols to choose the best among them to use in large networks.

Improving video conferencing application quality for a mobile terminal through cognitive radio

Cognitive radio (CR) is a form of wireless communication in which a transceiver can intelligently detect which communication channels are in use and which are not, and instantly move into vacant channels while avoiding occupied ones. This optimizes the use of available radio-frequency (RF) spectrum while minimizing interference to other users. In this paper, we propose a new approach which uses the CR for improving video conferencing application quality for a cognitive radio mobile terminal (CRMT). We also show through experimentation the interest of our approach.

Resource Management for End-to-End QoS in a Mobile Environment

The major challenge in a mobile environment is the provisioning of quality of service (QoS) guarantees that different applications demand considering the highly dynamic nature of this environment. In this context, providing QoS to mobile terminals is a very important field of research. In the integrated networks services, the majority of research seeks to extend the RSVP protocol to a mobile environment. Another way to obtain a better use of the resources is to determine the future locations of the mobile terminal. This paper describes a resource management approach for end-to-end QoS in the mobile networks; it is based on the QoS NSLP signaling application resulting from NSIS working group. This reservation is based on an object called MSpec (mobility specification) which determines the future location of the mobile terminal. The MSpec object is a part of a users mobility profile

Toward Cognitive Radio Resource Management Based on Multi-Agent Systems for Improvement of Real-Time Application Performance

Cognitive Radio (CR) is a promising technology that can alleviate the spectrum shortage problem by enabling unlicensed users equipped with CRs to coexist with incumbent users in licensed spectrum bands while causing no interference to incumbent communications. In this paper, we propose a new approach which uses CR for improving real-time application performance related to only one cognitive radio mobile terminal (CRMT). We also present a synthesis of research relating to dynamic spectrum allocation and sharing in the context of CR networks using multi-agent systems. In our future work, we will seek to improve real-time application performance related to many CRMT.

Prediction-based advanced resource reservation in mobile environments

This paper describes a novel approach for an advanced reservation protocol, MQoS-NSLP, to provide seamless real-time services to mobile users in wireless integrated services networks. The robustness of the proposed work is the result of a two-fold contribution. The first is the utilization of knowledge about user preferences, goals, and analyzed spatial conceptual maps to predict the users future location. The second contribution is a predictive advanced resources reservation protocol suitable for mobile environments. The protocol extends the original QoS-NSLP messages with new mobility specifications

Auction-Based Agent Negotiation in Cognitive Radio Ad Hoc Networks

The explosive growth of wireless services in recent years illustrates the growing demand for communications, so the spectrum becomes more congested. We know that static spectrum allocation is a major problem in wireless networks. Generally, these allocations lead to an inefficient use of spectrum. To solve the problem of congestion, cognitive radio networks use dynamic spectrum access. In this paper, we use a technique based on auctions theory known for its simplicity and facilitates the allocation of scarce resources.

Diffusing-CRN k-means: an improved k-means clustering algorithm applied in cognitive radio ad hoc networks

With increasing demand of new wireless applications and increasing number of wireless user’s, problem of spectrum scarcity arises. In this context, cognitive radio supports dynamic spectrum access to address spectrum scarcity problem. Cognitive radio defined the cognitive radio nodes by their ability to intelligently adapt the environment to achieve specific objectives through advanced techniques. The variance of channel availability for cognitive radio nodes degrades connectivity and robustness of this type of network; in this case the use of clustering is an effective approach to meet this challenge. Indeed, the geographical areas are homogeneous in terms of type of radio spectrum, radio resources are better allocated by grouping cognitive radio nodes per cluster. Clustering is interesting to effectively manage the spectrum or routing in cognitive radio ad hoc networks. In this paper, we aim to improve connectivity and cooperativeness of cognitive radio nodes based on the improvement of the k-means algorithm. Our proposed algorithm is applied in cognitive radio ad hoc networks. The obtained results in terms of exchange messages and execution time show the feasibility of our algorithm to form clusters in order to improve connectivity and cooperativeness of cognitive radio nodes in the context of cognitive radio ad hoc networks.

A novel approach to spectrum management in cognitive radio networks using agent coalition formation

Cognitive radio CR is a novel technology which uses an open spectrum allocation technique to make more efficient utilisation of the wireless radio spectrum and reduces the bottleneck on the frequency bands. In this paper, we develop a novel approach for spectrum allocation using a multiagent system method based on coalition that enables secondary user devices to work cooperatively with their neighbouring primary user devices. The fundamental aspect of our solution is the deployment of an agent on each device and these agents are grouped into coalitions where the powerful node is selected to be a leader. The leader of secondary users coalition organises the allocation requests based on their priorities using scheduling heuristics while the leader of primary users coalition handles the proposals for spectrum sharing. The simulation results confirm the intelligent management and the good performance of our approach.

QoS management for mobile users

The major challenge in wireless environment is the provision of quality of service (QoS) guarantees that different applications demand considering the highly dynamic nature of these environments. In this context, provide to mobile users the QoS required is a very important field of research. Our approach to improve the QoS in the wireless network is based on the user mobility profile, after the determination of this profile, an advance resources reservation is made for the mobile terminal solely in the locations where it can visit. The determination of this location is made after an observation phase during which the user is new and his mobility profile is unknown for the system. During the observation phase, the system can’t make advance resources reservation for the user. In this case, we use Agent technology in order to improve the QoS for this user.

Adapting radio resources in multicarrier cognitive radio using discrete firefly approach

The user resource allocation has attracted research attention in the context of the Cognitive Radio (CR) paradigm. Aiming at fully exploiting the frequency band unused by the primary users, it enables the secondary users to tune their transmission parameters and communicate within this band with a good Quality of Service (QoS). This paper targets the issue of radio resource adaptation according to the priority and the needs of the active users, the channel state and the availability of the frequency, in multicarrier transmission. The adaptation of such resources has been previously investigated and Particle Swarm Optimisation (PSO) and Cross Entropy (CE) approaches were shown to outperform their counterparts in terms of the convergence rate and the quality of the solution. Motivated by the great promises held by the newly proposed firefly approach, we have adapted its application as a multi-objective approach to optimise the communication quality of secondary users in a multicarrier system. The performance superiority of the proposed approach over PSO and CE techniques is assessed in terms of convergence speed, quality of solution and stability.