3,476 research outputs found
Implementation of QoS onto virtual bus network
Quality of Service (QoS) is a key issue in a multimedia environment because multimedia applications are sensitive to delay. The virtual bus architecture is a hierarchical access network structure that has been proposed to simplify network signaling. The network employs an interconnection of hierarchical database to support advanced routing of the signaling and traffic load. Therefore, the requirements and management of quality of service is important in the virtual bus network particularly to support multimedia applications. QoS and traffic parameters are specified for each class type and the OMNeT model has been described
Final report on the evaluation of RRM/CRRM algorithms
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
EVEREST IST - 2002 - 00185 : D23 : final report
Deliverable públic 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
Auction-based Bandwidth Allocation Mechanisms for Wireless Future Internet
An important aspect of the Future Internet is the efficient utilization of
(wireless) network resources. In order for the - demanding in terms of QoS -
Future Internet services to be provided, the current trend is evolving towards
an "integrated" wireless network access model that enables users to enjoy
mobility, seamless access and high quality of service in an all-IP network on
an "Anytime, Anywhere" basis. The term "integrated" is used to denote that the
Future Internet wireless "last mile" is expected to comprise multiple
heterogeneous geographically coexisting wireless networks, each having
different capacity and coverage radius. The efficient management of the
wireless access network resources is crucial due to their scarcity that renders
wireless access a potential bottleneck for the provision of high quality
services. In this paper we propose an auction mechanism for allocating the
bandwidth of such a network so that efficiency is attained, i.e. social welfare
is maximized. In particular, we propose an incentive-compatible, efficient
auction-based mechanism of low computational complexity. We define a repeated
game to address user utilities and incentives issues. Subsequently, we extend
this mechanism so that it can also accommodate multicast sessions. We also
analyze the computational complexity and message overhead of the proposed
mechanism. We then show how user bids can be replaced from weights generated by
the network and transform the auction to a cooperative mechanism capable of
prioritizing certain classes of services and emulating DiffServ and time-of-day
pricing schemes. The theoretical analysis is complemented by simulations that
assess the proposed mechanisms properties and performance. We finally provide
some concluding remarks and directions for future research
A resource management architecture for future mobile communications systems
This paper presents an overview of a hierarchical Resource Management architecture for future mobile communications systems. The architecture is designed to be generic and can therefore be adopted for a range of Radio Access Methodologies. In particular it provides a mechanism for radio resource management across airinterfaces such as those being defined for use with UMTS. Given the move towards packet-switched technologies both in the Core Network and the Radio Access Network [1], the architecture embraces the concept of statistical QoS applied to individual flows in the form of a commitment level. I
Mobility: a double-edged sword for HSPA networks
This paper presents an empirical study on the performance of mobile High Speed Packet Access (HSPA, a 3.5G cellular standard) networks in Hong Kong via extensive field tests. Our study, from the viewpoint of end users, covers virtually all possible mobile scenarios in urban areas, including subways, trains, off-shore ferries and city buses. We have confirmed that mobility has largely negative impacts on the performance of HSPA networks, as fast-changing wireless environment causes serious service deterioration or even interruption. Meanwhile our field experiment results have shown unexpected new findings and thereby exposed new features of the mobile HSPA networks, which contradict commonly held views. We surprisingly find out that mobility can improve fairness of bandwidth sharing among users and traffic flows. Also the triggering and final results of handoffs in mobile HSPA networks are unpredictable and often inappropriate, thus calling for fast reacting fallover mechanisms. We have conducted in-depth research to furnish detailed analysis and explanations to what we have observed. We conclude that mobility is a double-edged sword for HSPA networks. To the best of our knowledge, this is the first public report on a large scale empirical study on the performance of commercial mobile HSPA networks
Analysis of packet scheduling for UMTS EUL - design decisions and performance evaluation
The UMTS Enhanced Uplink (EUL) provides higher capacity, increased data rates and smaller latency on the communication link from users towards the network. In this paper we present a performance comparison of three distinct EUL scheduling schemes (one-by-one, partial parallel and full parallel) taking into account both the packet level characteristics and the flow level dynamics due to the (random) user behaviour.\ud
Using a very efficient hybrid analytical and simulation approach we analyse the three schemes with respect to performance measures such as mean file transfer time and fairness. In UMTS, a significant part of the system capacity will be used to support non-elastic voice traffic. Hence, part of our investigation is dedicated to the effects that the volume of voice traffic has on the performance of the elastic traffic supported by the EUL. Finally, we evaluate the impact that implementation specifics of a full parallel scheduler has on these measures.\ud
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Our main conclusion is that our partial parallel scheduler, which is a hybrid between the one-by-one and full parallel, outperforms the other two schedulers in terms of mean flow transfer time, and is less sensitive to volume and nature of voice traffic. However, under certain circumstances, the partial parallel scheduler exhibits a somewhat lower fairness than the alternatives
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