227 research outputs found

    EVEREST IST - 2002 - 00185 : D23 : final report

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    Deliverable pĂșblic del projecte europeu EVERESTThis deliverable constitutes the final report of the project IST-2002-001858 EVEREST. After its successful completion, the project presents this document that firstly summarizes the context, goal and the approach objective of the project. Then it presents a concise summary of the major goals and results, as well as highlights the most valuable lessons derived form the project work. A list of deliverables and publications is included in the annex.Postprint (published version

    Final report on the evaluation of RRM/CRRM algorithms

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    Deliverable public del projecte EVERESTThis deliverable provides a definition and a complete evaluation of the RRM/CRRM algorithms selected in D11 and D15, and evolved and refined on an iterative process. The evaluation will be carried out by means of simulations using the simulators provided at D07, and D14.Preprin

    The new enhancement of UMTS: HSDPA and HSUPA

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    During the last two decades, the world of the mobile communications grew a lot, as a consequence of the increasing necessity of people to communicate. Now, the mobile communications still need to improve for satisfies the user demands. The new enhancement of UMTS in concrete HSDPA and HSUPA is one of these improvements that the society needs. HSDPA and HSUPA which together are called HSPA, give to the users higher data rates in downlink and uplink. The higher data rates permit to the operators give more different types of services and at the same time with better quality. As a result, people can do several new applications with their mobile terminals like applications that before a computer and internet connection were required, now it is possible to do directly with the mobile terminal. This thesis consists in study these new technologies denominated HSDPA and HSUPA and thus know better the last tendencies in the mobile communications. Also it has a roughly idea about the future tendencies

    Comparative study between the generations of mobile communication 2G, 3G & 4G

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    Communication system has evolved from wired button telephone system to wireless mobile phone in the few years . With wider use of mobile communication which provides an easement to fast and easy communication mode. The study is on the comparative study between the 3 generations of mobile communication 2G, 3G & 4G. About the various data handling capacity of the three generation of mobile communication along with the services provided and basic technology behind the

    D2D-Based Grouped Random Access to Mitigate Mobile Access Congestion in 5G Sensor Networks

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    The Fifth Generation (5G) wireless service of sensor networks involves significant challenges when dealing with the coordination of ever-increasing number of devices accessing shared resources. This has drawn major interest from the research community as many existing works focus on the radio access network congestion control to efficiently manage resources in the context of device-to-device (D2D) interaction in huge sensor networks. In this context, this paper pioneers a study on the impact of D2D link reliability in group-assisted random access protocols, by shedding the light on beneficial performance and potential limitations of approaches of this kind against tunable parameters such as group size, number of sensors and reliability of D2D links. Additionally, we leverage on the association with a Geolocation Database (GDB) capability to assist the grouping decisions by drawing parallels with recent regulatory-driven initiatives around GDBs and arguing benefits of the suggested proposal. Finally, the proposed method is approved to significantly reduce the delay over random access channels, by means of an exhaustive simulation campaign.Comment: First submission to IEEE Communications Magazine on Oct.28.2017. Accepted on Aug.18.2019. This is the camera-ready versio

    Efficient Discovery Protocol for Ubiquitous Communication in Wireless Environment

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    Nowadays, according to the advances of the wireless network technologies and also mobile computing devices the concept of ubiquitous computing environments has become a considerable research area. Ubiquitous computing environment means an environment which is saturated by elements or devices with capacities of computing and communication. So, there are a lot of ways to develop and employ applications in such environment as infrastructure, but the most effective and general one is using service advertisements, service discovery and service remote invocation. In an Ad-hoc network which its devices make an ubiquitous computing environment, every device as a server node can announce various applications as services in the environment and at the same time every device is able to listen to the network interface and be aware of surrounding services and invoke the remote services.A mechanism which is needed to recognize surrounding services is called service discovery, this mechanism also clears how to advertise services, and invoke them. Type and method of discovery procedures play the critical role in quality and efficiency of services in ubiquitous environments. Because of these properties (small and mobile) there is a serious limitation for the resources of devices specially power resource. The problem is that the most of service discovery protocols are not effective for wireless Ad- Hoc networks and ubiquities environments, efficiency in case of service quality and power consumption. In this research a new mechanism and algorithm is designed to improve current wireless service discovery protocols. Analysis of the results has shown that the designed mechanism in most of the comparative parameters such as speed of service delivery, power consumption, and coverage of the services will act much better than the current discovery protocols. The proposed solution is compared with (directory based and directory-less based) of discovery protocols in ubiquitous environment in three states: mobile nodes, mobile and static nodes, and static nodes. It can be derived that the proposed model obtains fewer messages around 52% while maintain the same rate of service discovery and false rate of service discovery. The reduction of the number of posts per request coupled with the fact that devices with greater time availability transmit more responses in the proposed model, it can be concluded that energy consumption in devices with more restrictions will be decreased

    Wireless Cellular Mobile Communications

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    In this article is briefly reviewed the history of wireless cellular mobile communications, examined the progress in current second generation (2G) cellular standards and discussed their migration to the third generation (3G). The European 2G cellular standard GSM and its evolution phases GPRS and EDGE are described somewhat in detail. The third generation standard UMTS taking up on GSM/GPRS core network and equipped with a new advanced access network on the basis of code division multiple access (CDMA) is investigated too. A sketch of the perspective of mobile communication beyond 3G concludes this article
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