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Call admission control (CAC) functionality is a critical requirement for guarantee the desired quality of service (QoS) for voice calls in IP-based wireless networks. In this paper, three different CAC strategies for voice over IP (VoIP) traffic over wireless access networks with packet buffering are mathematically analyzed through a joint call and packet level discrete time teletraffic model. The...
HSPA (High Speed Packet Access) technologies have become an attractive solution for broadband wireless Internet access. This article evaluates the quality of service experimented by one HSPA user in the presence of multiple terminals sharing the cell capacity. The study focuses on Web traffic and includes analytical and simulation results, providing a basis for dimensioning and admission control in...
The volume of Internet traffic increases every year, caused by increased amounts of individual information. Quality of Service (QoS) controls is necessary to manage this traffic. Differentiated Service (Diffserv) is a promising technique to realize scalable QoS control in the internet; extensive efforts have been made for its practical use and it is already introduced in some networks. The control...
Dynamic routing is very important in terms of assuring QoS in today's packet networks especially for streaming and elastic services. Existing solutions dedicated to dynamic routing are often too complicated and seem to be not usable in real time traffic scenarios where transferred traffic may vary significantly. This was the main reason for research and new routing mechanism proposal which should...
For the issue of resource allocation in a heterogeneous multi-user downlink OFDMA system with both delay-constrained (DC) and non-delay-constrained (NDC) traffic, this paper proposes suboptimal joint subcarrier and power allocation (JSPA) for channel-aware queue-aware(CAQA) scheduling. The objective is to maximize the sum of all NDC users' logarithmic utility functions (achieving proportional fairness)...
Through sensing and utilizing available network resources, cognitive network can obviously increase network performance. In this paper, a distributed on-demand routing protocol with traffic awareness (TACR) is proposed for cognitive wireless network. This routing protocol establishes the path based on the cognition and reasoning of traffic loads in a network and it also meet quality of service (QoS)...
Multi-granular traffic is considered as the traffic generated by the high variety of applications supported by future Internet. Hybrid interconnection is a viable way to achieve the high throughput and flexibility required in the optical nodes with available optical and electronic technology. The task of finding a way to efficiently match these two key aspects is a challenge for possible short term...
Handover happens among access points which not only belong to the same network, but also belong to various networks. Handover decision algorithm is one of key issues which decides when and how handover happens. In this paper, a novel handover decision algorithm shielding physical realization of various networks is proposed, which uses GRA (Grey Relational Analysis) method and GPS(Global Position System)...
This paper reports on the results of service performance in FON network - Wi-Fi network where each hotspot has its owner, Fonero, who has priority in service, and the right to grant access to the limited number of visitors of his hotspot. Simulation model developed assuming that users in FON behave similar to the users in Wi-Fi, and taking into account service priority of Fonero. Results of simulation...
The IEEE802.16 (WiMAX) standard specifies the air interface of broad width access systems. Mesh topology is supported as an optional structure. In the mesh network, coordinated distributed scheduling is an important scheduling mode. Such mode permits traffic to be routed through other subscriber stations (SS) and occur directly between SSs. Xmt holdoff exponent is an import parameter in the mode....
Network multimedia applications constitute a large part of Internet traffic and present a big challenge because of their sensitivity to delay, packet loss and higher bandwidth requirement. The need for guaranteed delivery and lower delay is caused by propagation of more the one domain. The domains used in this paper are co-operating and communicating with each other and all of them support IPv6 QoS...
Quality of service support for MANETs is a challenging task due to dynamic topology and limited resources. The main purpose of QoS routing is to find a feasible path that has sufficient resources to satisfy the constraints. In this paper a novel QoS routing algorithm based on ant colony optimization is proposed. The proposed algorithm uses Ant-like agents to discover and maintain paths, that satisfy...
This paper presents a comprehensive system modeling and analysis approach for both predicting and controlling queuing delay at an expected value under multi-class traffic in a single buffer. This approach could effectively enhance QoS delivery for delay sensitive applications. Six major contributions are given in the paper: (1) a discrete-time analytical model is developed for capturing multi-class...
Researchers in the denial-of-service (DoS) field lack accurate, quantitative, and versatile metrics to measure service denial in simulation and testbed experiments. Without such metrics, it is impossible to measure severity of various attacks, quantify success of proposed defenses, and compare their performance. Existing DoS metrics equate service denial with slow communication, low throughput, high...
Optimization of IEEE 802.11e MAC protocol performance is addressed by modifying several parameters left open in the standard, like block size and acknowledgement policies in order to improve the channel efficiency. The use of small block sizes leads to a high overhead caused by the negotiation on the other hand, the use of large block sizes causes long delays, which can affect negatively real-time...
We propose a new scheme for multiclass packet scheduling which is a variant of EDF (earliest deadline first). The model corrects EDF domino effect in a nearly-overloaded system. Simulations results show that the proposed model performs better than classical EDF by enhancing QoS for soft-real time traffic without significant degradation of less constrained traffic.
As the integration of prevailing voice over Internet protocol (VoIP) technology and wireless local area network (WLAN), voice over WLAN (VoWLAN) is expected to experience a dramatic growth in the near future. However, increasing voice capacity of the system still remains a problem. In this paper, the voice capacity of "waiting-time dependent backoff (WDB)" algorithm proposed in our previous...
In this paper, an energy efficient adaptive modulation scheme is proposed for a wireless cognitive radio ad hoc network, where each node is equipped with cognitive radio and the network is an OFDMA system operating on time slots. In each slot, the users with new traffic demand will sense the spectrum and locate the available subcarrier set. Then they choose subcarriers with favorable channel condition...
We propose an adaptive offset time scheme in which the offset time is assigned according to the burst size. A specific algorithm is presented and the simulation results show an improvement in the network goodput.
A principal factor in sensor network design is energy efficiency. In this work, we propose to extend the lifetime of sensor networks using appropriate choice of sensor node distribution. The key idea of our scheme is to deploy more nodes in areas of extensive energy usage. Using this scheme of sensor node distribution, we use probabilistic angular routing to route data packets from the sensor nodes...
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