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The behavior of Networked Embedded Systems (NES) is not only driven by network components but also by the surrounding environment. To verify the correct behavior of such systems, different tests should be performed under different environmental conditions. The complexity and expense of testing such systems in real environments leads us to propose a simulation-based approach to tackle this problem...
The paper describes a service model for cost-effective event reporting to clients over a wide-area network. The service provider (SP) maintains multiple protocol mechanisms to replicate the event pages at different proxy nodes of the distribution network. The mechanisms, which embody server-driven and client-driven replica update schemes to synchronize the page copies, reduce the access latency on...
The IP Multimedia Subsystem (IMS) seems to be the technology that will prevail in Next Generation Networks (NGN s), since the interworking environment and the service flexibility that this technology offers to the currently deployed wireless broadband technologies makes it appealing to users, service developers and network operators. In this paper a heterogeneous network model based on the IMS that...
Two-way relaying promises considerable improvements on spectral efficiency in wireless relay networks. While most existing works focus on physical layer approaches to exploit its capacity gain, the benefits of two-way relaying on upper layers are much less investigated. In this paper, we study the cross-layer design and optimization for delay quality-of-service (QoS) provisioning in two-way relay...
Promising machine-to-machine (M2M) communication emerges to achieve ubiquitous communications among objects and the surrounding environment in everyday life. For a large M2M network to support scrupulous connections among abundant devices, sharing radio resource efficiently with the existing wireless networks while maintaining sufficient quality-of-service (QoS) for reliable communications becomes...
This paper investigates and compares the performance of the popular VoIP codecs G.711, G.723.1 and G.729A over an IP network based on SIP architecture, using RTP as a transport protocol. This is based on different simulations in order to evaluate the performance of each codec and to find the optimal codec. For this objective this paper analyzes Quality of service (QoS) parameters, principally delay,...
The quality-of-service (QoS) metrics in a wireless sensor network (WSN) of multiple sensor types depend on the performance of the network protocol layers, motivating a comprehensive cross-layer design approach to optimize QoS. Advances in energy-harvesting techniques enable increases in WSN lifetime by prolonging operation of the wireless nodes. While the primary objective of energy harvesting is...
The Internet Protocol Multimedia Subsystem (IMS) has been recognized as a common signaling architecture for providing next generation multimedia services. In order to enhance perceived service quality regardless of access network and device, IMS supports Quality of Service (QoS) negotiation and signaling. The IMS procedures used for that purpose are based on Session Initiation Protocol (SIP). Therefore,...
The Internet has now become such an important infrastructure that is capable of sending information within a very short time and easy to access. It is considered as public networks that provide affordable WAN services to most customers. Applications such as video conferencing, file transfer protocol and VoIP are the example of typical network applications supported by the Internet Protocol. Various...
In this paper, we propose relay transmission protocol based on SoQ(Satisfaction of QoS) for QoS enhancement and analyze the performance of the proposed method in Wireless USB Networks. In the proposed protocol, Wireless USB host executes the Satisfaction of QoS (SoQ) time slot allocation algorithm. And, in order to give devices with scarce resource another chance to improve QoS, the proposed relay...
A new scheduling module, the Selective Early Detection (SED) mechanism is proposed in this paper. An experimental evaluation in order to demonstrate how this algorithm succeeds in enhancing the quality, improving the performance and easing the deployment of a production level service is carried out. SED algorithm is useful in controlling the Actual average queue size, and hence the queuing delay,...
For ad-hoc wireless sensor networks (WSN), multi-hop routing has been adopted in order to save communication power consumption and to increase network lifetimes. In contrast to traditional multi-hop routing, the Opportunistic Routing (OR) protocol provides an alternative and efficient method for exploiting the spatial and temporal characteristics of wireless networks. One of the more important aspects...
VoIP is replacing traditional telephony system over PSTN as a more affordable communication tool on account of convergence of networks. Meanwhile, security issue brings more attention and becomes more important. SIP is based on text message. This makes the protocol easy to implement but also creates opportunity for hackers to steal or modify the messages. There exist a various approaches to secure...
Multimedia sensor network (MSN) has been deployed in many fields owing to its reliability, flexibility and availability of multimedia data. Correspondingly more challenges draw into the QoS guarantee research. In this paper, we establish a comprehensive performance analytical framework for MSN considering both the traffic self-similarity and stochastic service curve of MSN with S-MAC protocol based...
Transmission of video and imaging data requires both energy and QoS aware routing in order to ensure efficient usage of the sensors and effective access to the gathered information. In large-scale networks with a large number of sensor nodes, multiple sink nodes should be deployed to increase the manageability of the network and also to reduce the energy dissipation at each node. In this paper we...
Traditionally, a packet with errors, either due to channel noise or collisions, is discarded and needs to be retransmitted, leading to performance losses. Hybrid Automatic Retransmission reQuest (H-ARQ) and time diversity multipacket reception approaches, such as Network Diversity Multiple Access(NDMA), improve the system performance by requesting additional retransmissions and combining all the signals...
If network congestion occurs, packets cannot be delivered timely, the data rate decreases significantly and the required level of QoS cannot be achieved for all nodes. Especially in Home Area Networks (HANs) with limited uplink bandwidth for internet access, congestion is a major problem. Different approaches for congestion aware link sharing and QoS provisioning exist. Also the Distributed Fair Congestion...
The number of wireless applications, services and devices such as mobile telephone handsets, laptops and personal digital assistant (PDAs) are growing rapidly. The next generation wireless technology systems are being devised with the vision of heterogeneity where a mobile user will be connected with multiple wireless networks like GPRS/UMTS, IEEE 802.1x, WiMAX and satellite etc. To connect the above...
Virtual Desktop Infrastructures (VDIs) are gaining popularity in cloud computing by allowing companies to deploy their office environments in a virtualized setting instead of relying on physical desktop machines. Consolidating many users into a VDI environment can significantly lower IT management expenses and enables new features such as “available-anywhere” desktops. However, barriers to broad adoption...
In recent years, IEEE 802.11 Wireless Local Area Networks (WLANs) have emerged as one of the prevailing technologies for the broadband wireless access. Although IEEE802.16 wireless network has become a newer generation of wireless network, it will be used as wireless metropolitan area network in the beginning because of its price. IEEE 802.11 network will continue to be the most important wireless...
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