A manual selection of the Mobile Network Operator (MNO) to be used on a mobile device is possible through the respective user interface. Furthermore, mobile devices can be adjusted to select automatically the MNO based on the strongest signal strength, among the list of those MNOs the Subscriber Identity Module (SIM) card is allowed to be registered with. However, so far in modern mobile operating systems, such as Android and iOS, there is no available method in the public developer’s Application Programming Interface (API), which allows for an automatic and on-demand selection of the MNO by third- party applications. Recently, various research approaches assume the existence of an automatic and on-demand MNO selection mechanism to achieve different goals, such as breaking the termination rates monopoly (AbaCUS) or minimizing the non-ionizing radiation of mobile/wearable devices. The interest of such a mechanism has been raised three years ago by the Android developers community. Thus, this work here presents an automatic and on-demand MNO selection mechanism, that has been designed and implemented on the Android platform. For evaluation purposes the energy and end-to-end (e2e) time consumption while switching among MNOs using this mechanism is evaluated and as an applied example the data consumption of AbaCUS signaling messages is measured.

1. © 2014 UZH, CSG@IFI
An Automatic and On-demand
MNO Selection Mechanism
Christos Tsiaras, Samuel Liniger, Burkhard Stiller
Department of Informatics IFI, Communication Systems Group CSG,
University of Zürich UZH
tsiaras@ifi.uzh.ch, samuel.liniger@uzh.ch, stiller@ifi.uzh.ch
Krakow 06 May 2014 - NOMS 2014
Motivation
MNO Selection Mechanism
Evaluation

2. © 2014 UZH, CSG@IFI
Current Termination Service Situation
The mobile termination service, since the early days of mobile
communication, is considered to be a monopoly
Could any of
you connect
me with Alice?
Mobile network XAlice’s network
I am the only
network that
can connect
anyone with
Alice! q Only the Mobile Network
Operator (MNO) that Alice is
connected with can reach her
Bob

3. © 2014 UZH, CSG@IFI
Motivation
Alice’s MNOBob’s network
Bob Alice
I want to
call
Termination rateService rate
q Total cost of the call = Service rate + Termination rate
q Calling Party Pays (CPP) principle → Total cost

4. © 2014 UZH, CSG@IFI
Research Idea
Auction-based Charging User-centric System (AbaCUS)
q Auction
– Auction parameters
– Quality-of-Service (QoS) parameters
• Resources availability
• Voice quality
• Network access priority
– Price
q Automatic and on-demand
MNO selection mechanism
Alice’s
MNO
MNO X

5. © 2014 UZH, CSG@IFI
MNO Selection Mechanism Requirements
q Download it @ http://www.abacusproject.eu/
q Accessing the Android internal Application
Programming Interface (API)
– Obtain the original Android framework
• Compile own framework
• Extract it from a device
– Create a customized Android framework
• Access the internal API in an Integrated Development
Environment (IDE)
– Modify the IDE access rule
• Eclipse prohibits to use the internal API
q Sign the application with the system signature key

6. © 2014 UZH, CSG@IFI
Evaluation
q MNO switching time R1
q Mechanism’s energy consumption R2
q Mechanism’s data volume demand R3
010101

7. © 2014 UZH, CSG@IFI
Experiment
q Foreign SIM cards in roaming to simulate the SIM
cards acceptance
– Switching between every MNO pair 6 x 100 times
– 5 different time-frames
– Urban area inside a building
– Moving on a train

8. © 2014 UZH, CSG@IFI
MNO Switching Time -1 (R1)

9. © 2014 UZH, CSG@IFI
MNO Switching Time - 2 (R1)
q MNO switching time
independent of the:
– MNO
– Scenario
• Stable
• Moving

10. © 2014 UZH, CSG@IFI
MNO Switching Time Correlations (R1)
RSSI
Value
Signal strength
[dBm]
0 -113
1 -111
2-30 -109 to -53
31 > -51
99 Not known or not
detectable
q Performance independent of:
– Signal strength
– Time-frame

11. © 2014 UZH, CSG@IFI
Long MNO Switching Time (R1)
08:00 10:30 12:00 14:00 17:00 02:00
0
50
100
150
200
250
Time of the day
NumberoftimesMNOswitchingexceeded10s
q Potential affect of high cell occupancy

12. © 2014 UZH, CSG@IFI
Calling Time With MNO Switching (R1)
q Low time-overhead

13. © 2014 UZH, CSG@IFI
Energy Evaluation (R2)
Consumption 2G max talk
time [h]
2G power
[W]
3G max talk
time [h]
3G power
[W]
Voice Service 18.33 0.3333 8.67 0.705
Stand-by 710.00 0.0086 610.0 0.010
Process Power [W]
Talk 3G 0.7050
MNO selection moving 0.6536
MNO selection stable 0.5406
Talk 2G 0.3333
Power consumption overhead on average of a 3 minute
call: +(2.6-6.5)% battery consumption per call.

14. © 2014 UZH, CSG@IFI
Data Evaluation (R3)
Activity Stakeholder Received [B] Sent [B]
Register GCM* Caller/Callee 128 457
Service request Caller 358 (1) 796 (4)
Change MNO Callee 256 (2) 276 (3)
Unregister GCM Caller/Callee 128 437
Caller Callee Auction Authority
1. Service request
2. Change MNO
3. OK
4. Ready to call
*Google Cloud Messaging

15. © 2014 UZH, CSG@IFI
Conclusions
q An automatic and on-demand MNO selection
mechanism is usable
– Energy
– Time
q Access to the internal Android API is needed to get
access to the GSM modem
– Such method need to be published in the open API from
multiple mobile terminal equipment vendors
✔

16. © 2014 UZH, CSG@IFI
Thank you
Q&A
FLAMINGO