453 research outputs found
Understanding mobile network quality and infrastructure with user-side measurements
No full textMeasurement collection is a primary step towards analyzing and optimizing performance
of a telecommunication service. With an Mobile Broadband (MBB) network,
the measurement process has not only to track the network’s Quality of Service (QoS)
features but also to asses a user’s perspective about its service performance. The later
requirement leads to “user-side measurements” which assist in discovery of performance
issues that makes a user of a service unsatisfied and finally switch to another
network.
User-side measurements also serve as first-hand survey of the problem domain. In
this thesis, we exhibit the potential in the measurements collected at network edge by
considering two well-known approaches namely crowdsourced and distributed testbed-based
measurements. Primary focus is on exploiting crowdsourced measurements
while dealing with the challenges associated with it. These challenges consist of differences
in sampling densities at different parts of the region, skewed and non-uniform
measurement layouts, inaccuracy in sampling locations, differences in RSS readings
due to device-diversity and other non-ideal measurement sampling characteristics. In
presence of heterogeneous characteristics of the user-side measurements we propose
how to accurately detect mobile coverage holes, to devise sample selection process
so to generate a reliable radio map with reduced sample cost, and to identify cellular
infrastructure at places where the information is not public. Finally, the thesis unveils
potential of a distributed measurement test-bed in retrieving performance features
from domains including user’s context, service content and network features, and understanding
impact from these features upon the MBB service at the application layer.
By taking web-browsing as a case study, it further presents an objective web-browsing
Quality of Experience (QoE) model
Web Experience in Mobile Networks: Lessons from Two Million Page Visits
No full textMeasuring and characterizing web page performance is a challenging task.
When it comes to the mobile world, the highly varying technology characteristics coupled with the opaque network configuration make it even more difficult.
Aiming at reproducibility, we present a large scale measurements study of web page performance collected in eleven commercial mobile networks spanning four countries.
We build a dataset of nearly two million web browsing sessions to we shed light on the impact of different web protocols, browsers, and mobile technologies on the web performance.
We find that the impact of mobile broadband access is sizeable.
For example, the median page load time using mobile broadband increases by a third compared to wired access.
Mobility clearly stresses the system, with handover causing the most evident performance penalties.
Contrariwise, our measurements show that the adoption of HTTP/2 and QUIC has practically negligible impact.
Our work highlights the importance of large-scale measurements.
Even with our controlled setup, the complexity of the mobile web ecosystem is challenging to untangle.
For this, we are releasing the dataset as open data for validation and further research.
We also release together with the datasets we collected the scripts we use to produce the analysis we present in the paper. Please use plot_all.sh script to generate the plots in the paper, using the separate scripts from the "scripts" archive.
Should you use any of these resources, please also make an attribution using the following reference (provided here in bibtex format):
@inproceedings{rajiullah2019web,
title={{Web Experience in Mobile Networks: Lessons from Two Million Page Visits}},
author={Rajiullah, Mohammad and Lutu, Andra and Khatouni, Ali Safari and Fida, Mah-Rukh and Mellia, Marco and Brunstrom, Anna and Alay, Ozgu and Alfredsson, Stefan and Mancuso, Vincenzo},
booktitle={The World Wide Web Conference},
pages={1532--1543},
year={2019},
organization={ACM},
address = {San Francisco, CA, USA},
keywords = {Web Experience, HTTP2, QUIC, TCP, Mobile Broadband, Measurements}
}</pre
SURVEY OF HISTORY BASED ROUTING PROTOCOLS IN DELAY TOLERANT NETWORK
No full textFrequent changes in topology and the lack of infrastructure compel disrupted networks to avoid the use of traditional routing protocols. Rather than defining paths towards destinations, the routing tables store access chances of known nodes towards a specific destination. History of a node’s encounter is maintained in three different ways to find out its power of access to the rest of network nodes. The survey paper discusses various routing schemes based on the past encounter patterns of network nodes.Keywords: (Delay Tolerant Network) DTN; routing protocols; history-based routing; frequency; encounter; inter-contact duration; recency
Story of Adeline Yen Mah
No full textProducer, Eleanor Morris ; narrator, Connie Booth.Adeline Yen Mah, the author of Falling leaves, traces her and her family's life from Shanghai of the 1930s to the Cultural Revolution, through her life as a doctor in California
From the history of establishing People’s Movement (Rukh) of Ukraine and renewing “Prosvita” (1988-1991). A Memoir
No full textРозкрито процес зародження українського національного руху на переломі
80–90-х рр. ХХ ст. та його еволюцію, що призвела до відродження Товариства
“Просвіта” і створення Народного Руху України. Значну частину матеріалів склали
власні спогади автора про події у Львові.The author reveals the process of the genesis of Ukrainian national movement at the turn
of the 1990s and its evolution that led to the revival of the “Prosvita” society and establishing
of the People’s Movement (Rukh) of Ukraine. Considerable part of materials consists of
personal memoirs of the author; they mostly deal with the events that took place in Lviv
Spatial Interpolation based Cellular Coverage Prediction with Crowdsourced Measurements
No full textCoverage prediction has always been of great concern for mobile network operators. Yet the prevalent approach using analytical models assisted by drive testing based measurements is inherently inaccurate and expensive. We consider a promising alternative for coverage mapping involving crowdsourced measurements and spatial interpolation. In particular, we empirically study the accuracy of wide range of spatial interpolation techniques in different scenarios that capture the unique characteristics of crowdsourced measurements (inaccurate locations, sparse and non-uniform measurements, etc.), and find ordinary kriging to be a fairly robust technique
- …
