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A number of congestion control schemes which adopt the max-min fairness criterion and do not require maintenance of per flow states within the network have been proposed in the literature. The establishment of global asymptotic stability remains an open challenging research topic. In this paper, we show global asymptotic stability of two decentralized max-min congestion controllers in the absence and presence of queueing dynamics when the propagation delays are assumed to be zero. In particular, we show that these max-min congestion control schemes applied to a network of arbitrary topology, guarantee that the user sending rates converge asymptotically to the max-min allocation values for any arbitrary feasible initial condition. The second algorithm which accounts for queueing dynamics, typical in store and forward networks, does not only guarantee convergence of the sending rates to their max-min allocation values but also guarantees that the queue sizes within the network all converge to zero when there is only one bottleneck link at each path. © The authors 2015. 34 1 179 201

Many congestion control protocols have been recently proposed in order to alleviate the problems encountered by TCP in high-speed networks and wireless links. Protocols utilizing an architecture that is in the same spirit as the ABR service in ATM networks require estimates of the effective number of users utilizing each link in the network to maintain stability in the presence of delays. In this paper, we propose a novel estimation algorithm that is based on online parameter identification techniques and is shown through analysis and simulations to converge to the effective number of users utilizing each link. The algorithm does not require maintenance of per-flow states within the network or additional fields in the packet header, and it is shown to outperform previous proposals that were based on pointwise division in time. The estimation scheme is designed independently from the control functions of the protocols and is thus universal in the sense that it operates effectively in a number of congestion control protocols. It can thus be successfully used in the design of new congestion control protocols. In this paper, to illustrate its universality, we use the proposed estimation scheme to design a representative set of Internet congestion control protocols. Using simulations, we demonstrate that these protocols satisfy key design requirements. They guide the network to a stable equilibrium that is characterized by high network utilization, small queue sizes, and max-min fairness. In addition, they are scalable with respect to changing bandwidths, delays, and number of users, and they generate smooth responses that converge quickly to the desired equilibrium. © 2011 IEEE. 19 5 1499 1512 Cited By :8

In this paper we present a new queue length based Internet congestion control protocol which is shown through simulations to work effectively. The control objective is to regulate the queue size at each link so that it tracks a reference queue size chosen by the designer. To achieve the latter, the protocol implements at each link a certainty equivalent proportional controller which utilizes estimates of the effective number of users utilizing the link. These estimates are generated online using a novel estimation algorithm which is based on online parameter identification techniques. The protocol utilizes an explicit multi-bit feedback scheme and does not require maintenance of per flow states within the network. Extensive simulations indicate that the protocol is able to guide the network to a stable equilibrium which is characterized by max-min fairness, high utilization, queue sizes close to the reference value and no observable packet drops. In addition, it is found to be scalable with respect to changing bandwidths, delays and number of users utilizing the network. The protocol also exhibits nice transient properties such as smooth responses with no oscillations and fast convergence. © 2007 IEEE. 584 589 Sponsors: IEEE Systems, Man and Cybernetics Society Conference code: 70274 Cited By :4

It is shown that Enhanced UMTS will be an affordable solution for providing the required network quality and to reduce infrastructure investments in offices scenarios. System capacity results are obtained by using a system level simulator which considers traffic characterisation parameters and services usage in detail, among other. Results for the most profitable cell radius are obtained via an optimisation procedure based in economic aspects. A higher number of pico cells (with a smaller radius, around 30-32 m) can be installed in the future, when costs of deploying and maintaining the network decreases, allowing for supporting higher system capacity, and reducing prices. Our approach is based in a detailed services analysis, which represents a worst case situation relatively to the total services approach, because the later does not discriminate results for the different traffic classes. The impact of call blocking, handover failure, end-to-end delay, and delay variation are taken into account. © 2006 IEEE. Conference code: 72218 Cited By :2

Enhanced UMTS traffic characterisation parameters have been addressed for the offices scenario. By using a system level simulator, results concerning QoS measures as packet delay, blocking and handover failure probabilities have been obtained. If the cell radius decreases and the number of BSS increases the blocking probability decreases with a linear trend. One concludes that the supported traffic and the corresponding throughput significantly increase when the cell radius decreases. However, increasing system capacity by decreasing the cell radius causes an increase in the intensity of hand overs and a decrease in the throughput per BS. Hence, optimum values for the coverage distance will correspond to higher cell radius. Delay and delay variation are not a limitation. Sponsors: Conference code: 114330 Cited By :2

This paper presents a new system level simulator that has been developed to evaluate Radio Resource Management (RRM) techniques in UMTS (Universal Mobile Telecommunication Systems) and enhanced-UMTS networks. The simulator includes new implementations for the User Equipment, Node B, Radio Network Controller nodes and can evaluate parameters associated with UMTS or enhanced-UMTS performance, related to the introduction of RRM functions. The RRM functions implemented deal with admission control, packet scheduling, handover control, load control, and power control. The evaluation of RRM mechanisms is supported by the provision of appropriate radio propagation, traffic generation, and mobility models. 2005 396 403 Sponsors: IEEE Computer Society CREATE-NET INRIA ICST Intel Conference code: 67373 Cited By :2

Third generation and beyond mobile networks have brought about a demand for new services that refrain from the traditional unicast communication model. These are services demanding transmission to many receivers with acceptable efficiency and quality. In such networks radio resource management is a set of mechanisms responsible for maintaining quality of service over the radio interface. Power Control is the mechanism responsible for keeping signal interference at minimum levels and ensuring an adequate quality of service level so that the percentage of dropped calls is kept below the acceptable thresholds. The novelty of this work is proposing new approaches for efficient power control in the case of multicast services for 3G and beyond mobile networks, demonstrating simultaneously the tradeoff between the number of users and the average distance from the Node B when transmitting to a multicast group. © Copyright 2015 IEEE All rights reserved. Sponsors: Conference code: 114327 Cited By :2

In this paper we present a soft handover algorithm for wide band CDMA based E-UMTS networks and the associated power control algorithm. The handover and power control algorithms have been developed and implemented in the framework of a system level E-UMTS simulator developed under the IST SEACORN project. The paper provides a background on handover design techniques and explains the handover implementation. The soft handover algorithm has been modeled using the guidelines provided in the standards and the literature for W-CDMA intra-frequency handovers. The combination of established handover techniques with Enhanced UMTS is a novelty feature of this paper and provides a reference for further performance comparison. © 2005 IEEE. 3 1646 1651 Cited By :7

In this paper Enhanced UMTS offices scenarios and classes of services up to wideband are taken into account. A model is proposed for optimising Enhanced UMTS based in costs and revenues. A system level simulator is used to obtain the blocking probability, and other QoS measures, e.g., handover failure probability and delay. Using these results, one obtains the system capacity, i.e., the supported fraction of active users and throughput for a given grade of service. The profit (in percentage) was obtained, and the optimum (most profitable) cell radius was found. A higher number of pico-cells (with a cell radius around 34 m) will be a profitable solution for the optimisation of network planning. This will also allow for increasing system capacity and reducing prices. 523 527 Sponsors: Bechtel Nokia Conference code: 66377 Cited By :2

This paper presents a new active queue management scheme, fuzzy explicit marking (FEM), implemented within the differentiated services (Diffserv) framework to provide the congestion control using a fuzzy logic control approach. Network congestion control remains a critical and high priority issue. The rapid growth of the Internet and increased demand to use the Internet for time-sensitive voice and video applications necessitate the design and utilization of effective congestion control algorithms, especially for new architectures, such as Diffserv. As a result, a number of researchers are now looking at alternatively schemes to TCP congestion control. RED (random early detection) and its variants are one of these alternatives to provide quality of service (QoS) in TCP/IP Diffserv networks. The proposed fuzzy logic approach for congestion control allows the use of linguistic knowledge to capture the dynamics of nonlinear probability marking functions and offer effective implementation, use of multiple inputs to capture the (dynamic) state of the network more accurately, enable finer tuning for packet marking behaviors (either dropping a packet or setting its ECN - explicit congestion notification - bit) for aggravated flows, and thus provide better QoS to different types of data streams, such as TCP/FTP traffic or TCP/Web-like traffic, whilst maintaining high utilization. © 2003 IEEE. 312 319 Sponsors: IEEE Computer Society - Technical Committee on Simulation IEEE Communications Society Conference code: 99372 Cited By :14

This paper presents a new system level simulator that has been developed to evaluate E-UMTS (Enhanced Universal Mobile Telecommunication Systems) 3G Networks. The article describes how the simulator supports different mobility, propagation, and traffic generation models and how this simulation framework can be used to evaluate new protocols, algorithms, or resource management mechanisms. Specific models and performance details for a sample scenario of a business city center are also provided. 1 369 370 Sponsors: ACM, SIGAPP Conference code: 62941 Cited By :7

Thesis (Master) -- University of Cyprus, Faculty of Pure and Applied Sciences, Department of Computer Science, 2003. The continuously increasing use of computers in the Internet, as well as the need from new applications on quality of service, require efficient ways so the congestion in cases where the demand in bandwidth is increased decreases in minimal. For this reason, the quality of service has been turned into one of the most challenging sectors in the research of computer networks in the last years. The result of this research was the two IP architectures for quality of service: the Intserv and the Diffserv. Independently from which architecture will be selected to be used, in order to achieve quality of service we have the need to control the flow in the network. The Resource Management in DiffServ (RMD) is a recently proposed QoS framework that extends the DiffServ architecture with new principles, necessary to provide resource provisioning and admission control. It was developed to satisfy requirements regarding support of large amount of real time traffic on costly leased transmission lines. Integrated Dynamic Congestion Control (IDCC) is a congestion control scheme used for controlling the flow in the network. It offers high utilization of the bandwidth by regulating the rate by which the ordinary traffic is send. This M.Sc. Thesis aim to study and evaluate the performance of IDCC in a Resource Management Differentiated Services (RMDS) Environment. The main objective is to examine the combined framework reliability and robustness and the possibility that it could meet the strict QoS requirements of real time traffic. Some other issues are also examined, such as the implementation of the best effort controller and the use of a function that estimates the number of flows traversing a link. The simulation scenarios were implemented and tested with the use of the ns-2 simulator.