Network Architectures and Services, Georg Carle Faculty of Informatics Technische Universität München, Germany User assisted analysis of cellular network structures 26.10.2011 Author: Simon Wagner Advisor: Johann Schlamp Supervisor: Prof. Georg Carle
What did we do? ● We developed an Android application to collect information about the user's network 2 Simon Wagner - User assisted analysis of cellular network structures
Why did we do it? Value for the user: ● User can measure his mobile connection ● Collected data might be interesting for the user himself (e.g. comparing network availability for a provider) Value for us: ● We get to know how users access the internet on mobile devices ● We can take a look how users are using their mobile phones (e.g. GPS availability and accuracy) 3 Simon Wagner - User assisted analysis of cellular network structures
How did we do it? ● Measurements are conducted in the background without the users interactions. They are started by an Android background service that is started in a certain interval ● The user can deactivate the measurements if he wants to ● The user can measure his down- and upstream on his request ● The measured speed will then be reported to the user and us 4 Simon Wagner - User assisted analysis of cellular network structures
How did we do it? Collector store upload ● Measurements will get uploaded as JSON to our servers as soon as an internet connection is available and will be stored in a CouchDB instance ● Therefore new information can be collected without changing the storage backend ● CouchDB provides a safe storage 5 Simon Wagner - User assisted analysis of cellular network structures
How did we do it? Postgres DB synchronize ● Another server provides a web interface to our data ● Interested users can take a look at our collected data ● Presents some interesting data like recorded speed, availability of different network types, etc. ● Synchronizes from time to time with the storage server and updates its own database 6 Simon Wagner - User assisted analysis of cellular network structures
Web interface - Statistics The webinterface provides information about the performance of different networks and also serves informations about the collected statistics 7 Simon Wagner - User assisted analysis of cellular network structures
Web interface - Map The location of our measurement points is shown together with detected basestations (blue) and basestations from OpenCellID (white) 8 Simon Wagner - User assisted analysis of cellular network structures
User distribution ● Users are mainly from the USA ● Germany ranks second ● Rest comes from Europe 9 Simon Wagner - User assisted analysis of cellular network structures
Number of active users Number of active users Overall number of users: 459 Collected measurements: 242299 (as of September 1st) 10 Simon Wagner - User assisted analysis of cellular network structures
User distribution Measured Android OS distribution amongst our users: The distribution of Android versions does not differ much from the official data presented below 11 Simon Wagner - User assisted analysis of cellular network structures
Geolocation services When developing a location-aware Android application, you should ● use both geolocation services GPS has a reliable accuracy, network based location's accuracy is ● fluctating With GPS, accuracy is better than 73m in 75% of all measurements. ● Network based locations was only better than 90m in 25% of all cases 12 Simon Wagner - User assisted analysis of cellular network structures
Wifi usage Wifi encryption Wifi availability ● Smartphone users connect to wifi networks ● Decreases the load on the mobile networks ● Wifi connections are mostly encrypted ● Nearly no usage of WEP ● Mostly safe access via WPA ● Wifi-connected users don't deliver data about cellular networks, but give insight into Internet connections of home networks 13 Simon Wagner - User assisted analysis of cellular network structures
Mobile data usage ● 3G technology is available most of the time ● 2G (GPRS, EDGE) still used ● 2G might be used to save energy 14 Simon Wagner - User assisted analysis of cellular network structures
Mobile data usage ● Speed was also measured ● However some incorrect data was reported and only few speed measurements were available 15 Simon Wagner - User assisted analysis of cellular network structures
User tracking via global IP User has IP address 2.213.203.149 100 km User has still the same IP address here ● IP address travels with user ● GPRS core network handles the transition between base stations ● Public IP address tells the network provider of the user: The public IP belongs to an AS registered for the provider 16 Simon Wagner - User assisted analysis of cellular network structures
Future work – Possible Improvements ● Idea 1: Send phones through Germany to collect informations along the route ● Our users stay mostly at the same area, so sending a phone will deliver new informations ● Idea 2: Improve data collections: Start measurements on users' phones only where no data has been collected 17 Simon Wagner - User assisted analysis of cellular network structures
Summary ● Reaching users all over the world is easy ● Programmers should implement both GPS and network based location services ● Smartphone users use both Wifi and mobile data connections to access the internet ● WEP is finally getting rare ● 3G is widely available, 2G is however still used (possibly to save energy) ● Switching basestations still leaves you with the same IP 18 Simon Wagner - User assisted analysis of cellular network structures
Thank you for your attention. Questions? 19 Simon Wagner - User assisted analysis of cellular network structures
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