6,244 research outputs found
Control-Based Resource Management Procedures for Satellite Networks
This paper describes the resource management of a DVBRCS
geostationary satellite network. The functional modules
of the access layer aim at efficiently exploiting the link
resources while assuring the contracted Quality of Service
(QoS) to the traffic entering the satellite network. The main
novelty is the integration between the Connection Admission
Control and the Congestion Control procedures. Both them
exploit the estimation of the traffic load, performed by a
Kalman filter. The proposed solution has been analysed via
computer simulations, which confirmed their effectiveness
4. generĂĄciĂłs mobil rendszerek kutatĂĄsa = Research on 4-th Generation Mobile Systems
A 3G mobil rendszerek szabvĂĄnyosĂtĂĄsa a vĂ©gĂ©hez közeledik, legalĂĄbbis a meghatĂĄrozĂł kĂ©pessĂ©gek tekintetĂ©ben. EzĂ©rt lĂ©tfontossĂĄgĂș azon technikĂĄk, eljĂĄrĂĄsok vizsgĂĄlata, melyek a következĆ, 4G rendszerekben meghatĂĄrozĂł szerepet töltenek majd be. Több ilyen kutatĂĄsi irĂĄnyvonal is lĂ©tezik, ezek közĂŒl projektĂŒnkben a fontosabbakra koncentrĂĄltunk. A következĆben felsoroljuk a kutatott terĂŒleteket, Ă©s röviden összegezzĂŒk az elĂ©rt eredmĂ©nyeket. SzĂłrt spektrumĂș rendszerek KifejlesztettĂŒnk egy Ășj, rĂĄdiĂłs interfĂ©szen alkalmazhatĂł hĂvĂĄsengedĂ©lyezĂ©si eljĂĄrĂĄst. SzimulĂĄciĂłs vizsgĂĄlatokkal tĂĄmasztottuk alĂĄ a megoldĂĄs hatĂ©konysĂĄgĂĄt. A projektben kutatĂłkĂ©nt rĂ©sztvevĆ Jeney GĂĄbor sikeresen megvĂ©dte Ph.D. disszertĂĄciĂłjĂĄt neurĂĄlis hĂĄlĂłzatokra Ă©pĂŒlĆ többfelhasznĂĄlĂłs detekciĂłs technikĂĄk tĂ©mĂĄban. Az elĂ©rt eredmĂ©nyek Imre SĂĄndor MTA doktori disszertĂĄciĂłjĂĄba is beĂ©pĂŒltek. IP alkalmazĂĄsa mobil rendszerekben TovĂĄbbfejlesztettĂŒk, teszteltĂŒk Ă©s ĂĄltalĂĄnosĂtottuk a projekt keretĂ©ben megalkotott Ășj, gyƱrƱ alapĂș topolĂłgiĂĄra Ă©pĂŒlĆ, a jelenleginĂ©l nagyobb megbĂzhatĂłsĂĄgĂș IP alapĂș hozzĂĄfĂ©rĂ©si koncepciĂłt. A tĂ©makörben Szalay MĂĄtĂ© Ph.D. disszertĂĄciĂłja mĂĄr a nyilvĂĄnos vĂ©dĂ©sig jutott. Kvantum-informatikai mĂłdszerek alkalmazĂĄsa 3G/4G detekciĂłra Ăj, kvantum-informatikai elvekre Ă©pĂŒlĆ többfelhasznĂĄlĂłs detekciĂłs eljĂĄrĂĄst dolgoztunk ki. Ehhez Ășj kvantum alapĂș algoritmusokat is kifejlesztettĂŒnk. Az eredmĂ©nyeket nemzetközi folyĂłiratok mellett egy sajĂĄt könyvben is publikĂĄltuk. | The project consists of three main research directions. Spread spectrum systems: we developed a new call admission control method for 3G air interfaces. Project member Gabor Jeney obtained the Ph.D. degree and project leader Sandor Imre submitted his DSc theses from this area. Application of IP in mobile systems: A ring-based reliable IP mobility mobile access concept and corresponding protocols have been developed. Project member MĂĄtĂ© Szalay submitted his Ph.D. theses from this field. Quantum computing based solutions in 3G/4G detection: Quantum computing based multiuser detection algorithm was developed. Based on the results on this field a book was published at Wiley entitled: 'Quantum Computing and Communications - an engineering approach'
A novel admission control scheme for network slicing based on squatting and kicking strategies
New services and applications impose differentquality of service (QoS) requirements on network slicing. Tomeet differentiated service requirements, current Internet servicemodel has to support emerging real-time applications from 5Gnetworks. The admission control mechanisms are expected tobe one of the key components of the future integrated serviceInternet model, for providing multi-level service guarantees withthe different classes (slices) of services. Therefore, this paperintroduces a new flexible admission control mechanism, basedon squatting and kicking techniques (SKM), which can beemployed under network slicing scenario. From the results, SKMprovides 100% total resource utilization in bandwidth contextand 100% acceptance ratio for highest priority class underdifferent input traffic volumes, which cannot be achieved byother existing schemes such as AllocTC-Sharing model due topriority constraints.Peer ReviewedPostprint (published version
Distributed QoS Guarantees for Realtime Traffic in Ad Hoc Networks
In this paper, we propose a new cross-layer framework, named QPART ( QoS br>rotocol for Adhoc Realtime Traffic), which provides QoS guarantees to real-time multimedia applications for wireless ad hoc networks. By adapting the contention window sizes at the MAC layer, QPART schedules packets of flows according to their unique QoS requirements. QPART implements priority-based admission control and conflict resolution to ensure that the requirements of admitted realtime flows is smaller than the network capacity. The novelty of QPART is that it is robust to mobility and variances in channel capacity and imposes no control message overhead on the network
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A connection-level call admission control using genetic algorithm for MultiClass multimedia services in wireless networks
Call admission control in a wireless cell in a personal communication system (PCS) can be modeled as an M/M/C/C queuing system with m classes of users. Semi-Markov Decision Process (SMDP) can be used to optimize channel utilization with upper bounds on handoff blocking probabilities as Quality of Service constraints. However, this method is too time-consuming and therefore it fails when state space and action space are large. In this paper, we apply a genetic algorithm approach to address the situation when the SMDP approach fails. We code call admission control decisions as binary strings, where a value of â1â in the position i (i=1,âŠm) of a decision string stands for the decision of accepting a call in class-i; a value of â0â in the position i of the decision string stands for the decision of rejecting a call in class-i. The coded binary strings are feed into the genetic algorithm, and the resulting binary strings are founded to be near optimal call admission control decisions. Simulation results from the genetic algorithm are compared with the optimal solutions obtained from linear programming for the SMDP approach. The results reveal that the genetic algorithm approximates the optimal approach very well with less complexity
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
Joint in-network video rate adaptation and measurement-based admission control: algorithm design and evaluation
The important new revenue opportunities that multimedia services offer to network and service providers come with important management challenges. For providers, it is important to control the video quality that is offered and perceived by the user, typically known as the quality of experience (QoE). Both admission control and scalable video coding techniques can control the QoE by blocking connections or adapting the video rate but influence each other's performance. In this article, we propose an in-network video rate adaptation mechanism that enables a provider to define a policy on how the video rate adaptation should be performed to maximize the provider's objective (e.g., a maximization of revenue or QoE). We discuss the need for a close interaction of the video rate adaptation algorithm with a measurement based admission control system, allowing to effectively orchestrate both algorithms and timely switch from video rate adaptation to the blocking of connections. We propose two different rate adaptation decision algorithms that calculate which videos need to be adapted: an optimal one in terms of the provider's policy and a heuristic based on the utility of each connection. Through an extensive performance evaluation, we show the impact of both algorithms on the rate adaptation, network utilisation and the stability of the video rate adaptation. We show that both algorithms outperform other configurations with at least 10 %. Moreover, we show that the proposed heuristic is about 500 times faster than the optimal algorithm and experiences only a performance drop of approximately 2 %, given the investigated video delivery scenario
Multiplexing regulated traffic streams: design and performance
The main network solutions for supporting QoS rely on traf- fic policing (conditioning, shaping). In particular, for IP networks the IETF has developed Intserv (individual flows regulated) and Diffserv (only ag- gregates regulated). The regulator proposed could be based on the (dual) leaky-bucket mechanism. This explains the interest in network element per- formance (loss, delay) for leaky-bucket regulated traffic. This paper describes a novel approach to the above problem. Explicitly using the correlation structure of the sourcesâ traffic, we derive approxi- mations for both small and large buffers. Importantly, for small (large) buffers the short-term (long-term) correlations are dominant. The large buffer result decomposes the traffic stream in a stream of constant rate and a periodic impulse stream, allowing direct application of the Brownian bridge approximation. Combining the small and large buffer results by a concave majorization, we propose a simple, fast and accurate technique to statistically multiplex homogeneous regulated sources. To address heterogeneous inputs, we present similarly efficient tech- niques to evaluate the performance of multiple classes of traffic, each with distinct characteristics and QoS requirements. These techniques, applica- ble under more general conditions, are based on optimal resource (band- width and buffer) partitioning. They can also be directly applied to set GPS (Generalized Processor Sharing) weights and buffer thresholds in a shared resource system
Study of the CAC mechanisms for telecommunications systems with adaptive links according to propagation conditions
This paper presents the framework and the activities of a PhD research work in progress supported by Alcatel Alenia Space in collaboration with TeSA and SUPAERO. It deals with Connection Admission Control (CAC) for Telecommunications Systems with adaptive links according to propagation conditions. Indeed, in high frequency bands communications, deep fadings may occur because of atmospheric propagation losses. The mitigation techniques used to counteract fades impacts the system capacity, therefore the CAC mechanism. The CAC which only uses current capacity information may lead to intolerable dropping of admitted connection, and thus breaches the QoS guarantees made upon connection acceptance. New CAC mechanisms shall be studied to take into account the capacity variation and the mitigation techniques (IFMT) developed to compensate the attenuation in Ka and above frequency range
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