| 1. |
- Aktas, Bagsen, et al.
(författare)
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Evaluation of User Perceived Performance in Sparce Infrastructure Wireless Systems
- 2004
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Konferensbidrag (refereegranskat)abstract
- This work tries to evaluate the user perceived performance in a wireless system based on sparse infrastructure (islands of coverage).We investigate a mobile user in a Manhattan environment and the considered service is web browsing. Data caching in the use terminal is employed in order to hide the discontinuities of coverage. We show that for this particular application, the user's behavior of revisiting pages previously accessed makes caching a way to increase the user perceived coverage. Our results show that at low levels of effective area coverage caching brings a large improvement, while the gain is not significant at high levels. If the sparse coverage network is overlaid over a cellular system the obtained results show potential for significant cost savings.
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| 2. |
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| 3. |
- Berggren, Fredrik, et al.
(författare)
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Multi-radio resource management for ambient networks
- 2005
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Ingår i: IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC. - : IEEE. - 9783800729098 ; , s. 942-946
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Konferensbidrag (refereegranskat)abstract
- The Ambient Networks concept targets forthcoming dynamic communication environments, characterized by the presence of a multitude of different wireless devices, radio access technologies, network operators and business actors, which can form instant inter-network agreements with each other. MultiRadio Resource Management (MRRM) mechanisms, coordinating several radio accesses, fulfill a key role for providing wireless services with improved resource efficiency, coverage and service quality. This paper presents an MRRM concept for Ambient Networks, describes the principal MRRM functions and discusses design criteria.
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| 4. |
- Bria, Aurelian, et al.
(författare)
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4th Generation Wireless Infrastructures : Scenarios and Research Challenges
- 2001
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Ingår i: IEEE personal communications. - : IEEE. - 1070-9916 .- 1558-0652. ; 8:6, s. 25-31
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Tidskriftsartikel (refereegranskat)abstract
- A "fourth generation" of wireless systems, likely to appear after the successful deployment of the current third-generation systems, is frequently debated these days. This article presents some of the results of the Fourth Generation Wireless project (4GW) of the Personal Computing and Communications program (PCC), the major Swedish academic research effort on future communications systems, launched in late 1997. In the 4GW project, scenarios have been used as tools for formulating relevant research topics related to future wireless systems. By working with scenarios the project group has been able to challenge some of the assumptions commonly made in the field of wireless research. Since the project group is multidisciplinary, the work has also helped the members of the project group to understand the differences between the research traditions to which they belong. The scenarios, as well as the ensuing research into various wireless related topics, point to a vision of fourth-generation systems where "low-hierarchy" user-deployed infrastructures are the prime candidate. Fourth-generation systems will offer short- to moderate-range communications with very high data rates (>100 Mb/s). They are likely to employ array signal processing and ad hoc operation to provide the required coverage. A key aspect of their design will be the fact that they will be deployed in environments where large-scale wireless, and wired, infrastructures are already in operation.
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| 5. |
- Bria, Aurelian, et al.
(författare)
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Cost-Based Resource Management for Filecasting Services in Hybrid DVB-H and 3G systems
- 2008
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Ingår i: 2008 IEEE INTERNATIONAL SYMPOSIUM ON WIRELESS COMMUNICATION SYSTEMS (ISWCS 2008). - NEW YORK : IEEE. - 9781424424887 ; , s. 159-163
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Konferensbidrag (refereegranskat)abstract
- This paper describes and evaluates a novel resource management technique for minimizing the file transmission cost in a hybrid cellular-broadcasting system. While DVB-H technology is utilized for wide area broadcasting, the 3G-HSDPA(1) system takes the role of providing not only feedback about reception conditions, but also on-demand repair information to the users that have missed part of the DVB-H transmissions. The Application Layer - Forward Error Correction with Raptor coding is used to generate parity data that is sent to the users through both cellular and broadcasting system. Our results show significant potential for cost reduction under certain settings and scenarios. Overall, we think that the outcomes of this study should encourage the interworking of cellular 3G and DVB-H broadcasting systems, in an effort to achieve cost efficient delivery of multimedia content to mobile users.
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| 6. |
- Bria, Aurelian
(författare)
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Cost-based resource management in hybrid cellular-broadcasting systems
- 2005
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Ingår i: VTC2005-SPRING: 2005 IEEE 61ST VEHICULAR TECHNOLOGY CONFERENCE, VOLS 1-5, PROCEEDINGS. - New York : IEEE. - 0780388879 ; , s. 3183-3187
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Konferensbidrag (refereegranskat)abstract
- This article introduces a cost based framework for the resource management in hybrid cellular-broadcasting systems with adaptive data rate. The considered service is delivery of multimedia items to the cache memory of user terminals. The problem investigated here is the minimization of the delivery cost per item, given that we have at our disposal a cellular and a broadcasting system. The proposed solution is to search for optimum set of users that are assigned to the broadcasting radio access and the respective data rate for serving them. The simulations performed on a test bed show that it is possible to achieve even four to five times reduction in cost per item if we employ both infrastructures, compared to a simpler strategy that assumes the transmission to only one of them. This significant gain justify the need for centralized resource management of the cellular and broadcasting systems. We have identified also situations when this gain is not significant, hence centralized management is not needed. Both situations are possible in realistic environments.
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| 7. |
- Bria, Aurelian
(författare)
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Cost Based Resource Management in Hybrid Cellular-Broadcasting Systems
- 2004
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Konferensbidrag (refereegranskat)abstract
- This article presents ongoing work on the problem of minimization of delivery cost per item for a given set of multimedia items, under the assumption that we have at our disposal a cellular and a broadcasting infrastructure covering the same service area. Only best effort traffic is considered. The center of our investigations is a generic mobile network operator. We consider two scenarios: the MNVO (Mobile Network Virtual Operator) and the Integrator Operator. We defined a cost model for each scenario. Our approach to the problem is to propose a suitable resource management mechanism which takes the transmission cost as an input for assigning different data traffic to the infrastructure that delivers it cheapest.
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| 8. |
- Bria, Aurelian
(författare)
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Digital broadcasting and mobile cellular networks to provide asymmetric data services - A survey
- 2002
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Konferensbidrag (refereegranskat)abstract
- High demand for mobile Internet services and interactive services are expected to characterize the user of the future wireless systems. For a large number of applications the user terminal will have to receive massive amount of information while sending only a few data. Exploiting this fact in the infrastructure design may have significant implications on the deployment cost of the infrastructure since higher powers can be used at the transmitting sites. Emerging examples include the integration of digital broadcasting systems with personal communication systems. Being capable of taking advantage of future digital broadcasting infrastructure (DAB/DVB-T) and the spectrum allocated for radio and TV broadcasting in VHF/UHF band, the new hybrid systems show promising performance and especially good business opportunities when deployed in wide areas with fairly low user densities. The objective of the paper is to evaluate the potential of digital broadcasting systems (mainly DVB-T) when using them as a high-speed downlink channel in a hybrid system providing large-scale asymmetric services. This investigation is part of the research on 4th Generation of Wireless Systems supported by Swedish Personal Computing and Communication program (PCC).
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| 9. |
- Bria, Aurelian
(författare)
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Future Hybrid Cellular-Broadcasting Systems for Multimedia Multicasting
- 2006
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Ingår i: Second International Conference on Wireless and Mobile Communications, ICWMC 2006. - : IEEE. - 0769526292 ; , s. 18-
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Konferensbidrag (refereegranskat)abstract
- This paper discusses hybrid cellular-broadcasting systems as an alternative for future delivery of wireless multimedia multicast services. A resource management framework is proposed, with the objective of minimizing the cost of multicasting transmissions. A comparison with traditional cellular and broadcasting systems is performed, showing the advantages of the hybrid solution under specific settings. Several implementation issues are investigated, as the number of broadcasting modulation and coding rates (MCR) and the importance of radio link monitoring. Dynamic control of the coverage of the broadcasting system by choosing from a pre-defined set of MCRs is shown to be the most important requirement for minimizing transmission cost. As the existing digital broadcasting technologies do not offer the possibility to dynamically change the MCR, several possibilities to overcome this are identified.
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| 10. |
- Bria, Aurelian
(författare)
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Hybrid cellular-broadcasting infrastructure systems : radio resource management issues
- 2006
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis addresses the problem of low-cost multicast delivery of multimedia content in future mobile networks. The trend towards reuse of existing infrastructure for cellular and broadcasting for building new systems is challenged, with respect to the opportunities for low cost service provision and scalable deployment of networks. The studies outline significant potential of hybrid cellular-broadcasting infrastructure to deliver lower-cost mobile multimedia, compared to conventional telecom or broadcasting systems. Even with simple interworking techniques the achievable cost savings can be significant, at least under some specific settings. The work starts with a foresight study shaped around four scenarios of the future, and continues with the introduction of a high-level framework for radio resource management in Ambient Networks. Two approaches on the hybrid system architecture are considered. The first one assumes different degrees of interworking between conventional cellular and broadcasting systems, in single and multi-operator environments. Second, is a broadcast only system where cellular sites are used for synchronized, complementary transmitters for the broadcasting site. In the first approach, the key issue is the multi-radio resource management, which is strongly affected by the degree of integration between the two networks. Two case studies deal with the problem of delivering, for lowest cost, a data item to a certain number of recipient users. A flexible broadcasting air interface, which offers several transmission data rates that can be dynamically changed, is demonstrated to significantly increase cost efficiency under certain conditions. An interesting result is that real-time monitoring of the user reception conditions is not needed, at least when multicast group is large. This indicates a high degree of integration between cellular and broadcasting networks may not by generally justified by visible cost savings. Scalability of the hybrid infrastructure deployment is the main topic in the second approach. For a DVB-H type of network, the numerical evaluations show that achievement of economies of scale while increasing network capacity and coverage, by employing higher modulation and coding rate or installing new transmission sites, is difficult. Therefore, a technique based on application-layer forward error correction with Raptor codingA is suggested for enabling a flexible trading between system capacity, perceived coverage and delay, in the case of mobile users.
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