scholarly journals Real-time delay statistics in wireless IP networks

2012 ◽  
Vol 10 ◽  
pp. 105-111 ◽  
Author(s):  
D. Huo

Abstract. In the wireless communication, the variation of the transmission delay is called jitter and is one of the variables responsible for the degradation of the service quality. Jitter is present in every section of the transmission system. Its stochastic behavior depends on the technology implemented in the system and the service provided by the system. This paper focuses on mathematical modeling and phenomenological analysis of the jitter encountered by the real-time services in a wireless network. Using the data made available to the public by the wireless industry, we explore the stochastic characterizations of the jitter in a wireless IP networks. Within the scope of real-time service, we studied the relation between delay, jitter and the inter-packet time. Evaluation of the sample data indicates a long range dependence of the inter-packet time of the received packets in a real-time connection. The result helps understanding the transmission delay encountered by the real-time service over wireless IP networks.

2015 ◽  
Vol 50 (2) ◽  
pp. 59-76 ◽  
Author(s):  
Hadaś Tomasz

Abstract On April 1, 2013 IGS launched the real-time service providing products for Precise Point Positioning (PPP). The availability of real-time makes PPP a very powerful technique to process GNSS signals in real-time and opens a new PPP applications opportunities. There are still, however, some limitations of PPP, especially in the kinematic mode. A significant change in satellite geometry is required to efficiently de-correlate troposphere delay, receiver clock offset, and receiver height. In order to challenge PPP limitations, the GNSS-WARP (Wroclaw Algorithms for Real-time Positioning) software has been developed from scratch at Wroclaw University of Environmental and Life Science in Poland. This paper presents the GNSS-WARP software itself and some results of GNSS data analysis using PPP and PPP-RTK (Real-Time Kinematic) technique. The results of static and kinematic processing in GPS only and GPS + GLONASS mode with final and real-time products are presented. Software performance validation in postprocessing mode confirmed that the software can be considered as a state-ofthe- art software and used for further studies on PPP algorithm development. The real-time positioning test made it possible to assess the quality of real-time coordinates, which is a few millimeters for North, East, Up in static mode, a below decimeter in kinematic mode. The accuracy and precision of height estimates in kinematic mode were improved by constraining the solution with an external, near real-time troposphere model. The software also allows estimation of real-time ZTD, however, the obtained precision of 11.2 mm means that further improvements in the software, real-time products or processing strategy are required.


2014 ◽  
Vol 5 (10) ◽  
pp. 3946-3951 ◽  
Author(s):  
Weiguang Ma ◽  
Dongxue Han ◽  
Min Zhou ◽  
Hao Sun ◽  
Lingnan Wang ◽  
...  

Using utg-C3N4/TiO2, a photoelectrochemical platform was designed for the sensing of global antioxidant capacity, which presented a rapid response, and anti-fouling and colour-interference-proof properties.


2018 ◽  
Vol 137 ◽  
pp. 301-309 ◽  
Author(s):  
J.P.R. Sorensen ◽  
A. Vivanco ◽  
M.J. Ascott ◽  
D.C. Gooddy ◽  
D.J. Lapworth ◽  
...  

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