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Tight synchronization timing is expected to play a crucial role for the realization of emerging Internet of Things (IoT) high value real-time applications such as smart transportation and smart grid. Most packet-based synchronization protocols require two-way communications delay symmetry for precise accuracy. The Precision Time Protocol (PTP) provides mechanisms to measure and take into account the...
Accuracy and power saving are two important quality of service (QoS) metrics in most applications of wireless sensor networks (WSNs) especially in acoustic target localization. The middleware layer of WSNs is responsible to properly manage the network-level resources and accurately setting the network parameters in support of these two application-level QoS metrics. A critical middleware-level task...
Active measurement, which can provide end-to-end measurements of network performance, is critical since the Internet is managed by multiple organizations. Recently, on the active measurement of delay and loss, Baccelli et al reported that many probing policies can be used to provide appropriate estimation in addition to the traditional policy based on PASTA property if the volume of probe stream is...
It is not easy to achieve real-time video transmission testbed on WiMax, due to the lack availability of WiMax networks. This paper presents a ns-2 based emulator to evaluate the quality of multicast video services transmitted over an IEEE 802.16 wireless network. The impact of the modulation schemes and the cyclic prefix, on the throughput and video quality were discussed and the performance of the...
Time and frequency alignment is critical for ensuring QoS for application such as voice, real-time video, wireless hand-off, and data over a converged access medium. To satisfy the accuracy of time synchronization, both adjusting Communication path asymmetry and ratio of frequency between the time-aware systems are important. Network Time Protocol (NTP) is not satisfies time-sensitive applications...
Quality of Service (QoS) measurement in large-scale QoS networks is required to be both cost effective and well performed. Common PC-based QoS measurement often suffers from measurement accuracy problems, especially for delay distribution edge (99.9 percentile) measurement. We propose a generic measurement accuracy evaluation method applicable for any delay measurement equipment. Applying this evaluation...
All wireless systems require the precise timing synchronization to satisfy the higher quality of service (QoS) requirements. Particularly, timing synchronization between base stations (BSs) during soft handover is required to increase the diversity gain of soft handover. Current timing synchronization protocol (e.g. IEEE1588, GPS) updates the synchronization at fixed time duration and it causes the...
Resource management in differentiated services (RMD) is a simple, scalable signaling method for resource reservation within a differentiated services domain. However, the algorithms used in RMD reservation-based mode cannot accurately maintain the aggregated reservation state. In this paper we present a synchronized control mechanism that can accurately control the aggregated reservation state. Our...
Acoustic target tracking is one of the application areas of wireless sensor networks (WSNs) in which time synchronization error influences the results of target tracking. Algebraic numerical methods are used to solve simultaneous equations of target tracking. A more efficient approach is to use algebraic geometry for solving simultaneous equations of target tracking, but the analytic study of error...
Maintaining synchronization of clocks between wireless systems is a well known problem of which significant research has been performed. This has lead to a variety of methods introduced to maintain clock synchronization. Typically, works are heavy weight in that they require constant communication between systems in order to maintain clock synchronization on the order of microseconds. Unfortunately,...
Time and frequency alignment is critical for ensuring QoS for applications such as voice, real-time video, wireless hand-off, and data over a converged access medium. To satisfy the accuracy of time synchronization, propagation delay measurement is required between time-sensitive devices. There is existing network technology for time synchronization, such as network time protocol (NTP), IEEE 1588...
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