1. Final Year Project LYU0301 Using GSM Cell Information on Mobile Phone Mok Ming Fai CEG mfmok1@cse Lee Kwok Chau CEG leekc1@cse

2. Agenda Symbian OS Location-based services (LBS) Connectivity of GSM base stations and mobile phones Using GSM cell information Example application: MTRTravaller Future Work

3. Symbian and Symbian OS Symbian: a software licensing company owned by Ericsson, Nokia, Panasonic, Psion, Samsung Electronics Siemens and Sony Ericsson. Symbian OS: standard operating system for data-enabled mobile devices

4. Symbian OS Currently supported mobile phones Nokia 6600, 7650, 3650, N-Gage and 9210 Communicator Sony Ericsson P800, P900 Motorola A920 Fujitsu F2051, F2102V New mobile phones supporting Symbian OS Samsung SGH-D700 Siemens SX1 Sendo X BenQ P30

5. Characteristics of Symbian OS Integrated multimode mobile telephony Open application environment Open standards and interoperability Multi-tasking Fully object-oriented and component based Flexible user interface design

6. Special Features in Symbian OS Error Handling Cleanup Stack Two-phase Constructions Active Object implements multi-tasking without using multithread One active scheduler per thread cooperating with one or mor active objects Non-preemptive, no mutual exclusion codes are needed

7. Programs Written for Symbian OS Robot Hello World Illustrations of the use of GUI components and basic APIs Nokia Square Illustrations of the basic APIs and the structure of Symbian- based applications

8. Location-Based Services (LBS) Services are provided based on user’s current location. Applicable on different fields: Driving Billing Shopping Guides Security Games and Entertainment...... Each of them requires different accuracy and latency.

9. Current Technologies on LBS 1) Global Positioning System (GPS) Good Accuracy: 30-100m Poor indoor and urban-area capabilities Generally high power consumption Expensive hardware 2) 3 rd Generation GSM (3G) Need time to replace current mobile network 3) Modified SIM Card Cooperation with telco 4) Global System for Mobile Communications (GSM) Common regular mobile phone network standard Available on ordinary cell phones

10. Operation of Mobile Phone Connectivity Location: [50] Cell ID: [1] Location: [50] Cell ID: [2] Location: [50] Cell ID: [3] Location: [50] Cell ID: [4]

11. Using GSM Cell Information Main idea: each base station may somehow indicate certain ‘information’ about location or region Cell information includes: Location ID Cell ID Received Signal Strength

12. Traditional Cell Information Collection Methods 1) Communicating with GSM modem Using AT command Require different kinds of hardware AT+CREG? +CREG:, [,50,7474] Location: [50] Cell ID: [7474]

13. Traditional Cell Information Collection Methods 2) Phone engineering mode Tell you a list of cell information Need to record them manually

14. Getting Cell Information via Symbian API Problem: Current Nokia SDK doesn’t provide any method for retrieving GSM cell information The internal library of the phone actually contains such API Solution: Use header file from other Symbian SDK GSMStatus Integrate current cell information and application

15. Cell Information for LBS Accuracy depends on: Base station deployment Cell size Pico-cell: 10-1000m Micro-cell: 100-1000m Small Macro-cell: 1000-3000m Large Macro-cell: 3000-30km Not accurate enough telling where you are How can we make use of such information?

16. Different registered cell in a particular location each time Problem of Pure Cell ID Detection Location: [50] Cell ID: [1] Location: [50] Cell ID: [2] Location: [50] Cell ID: [3] Location: [50] Cell ID: [4]

17. Pure Cell Detection VS Cell Change Event Event of Entering / Leaving a boundary Provide transition Information (from 1 cell to another)

18. Cell IDs in the 2D Space Initiatives To locate the approximate location of a mobile phone uses with a program run on Symbian OS Determining GSM cells coverage and their distribution Plot a cell ID-to-location map Locate current position of a mobile device

19. Cell ID Data Collection Collected location ID and cell ID pairs for two telcos in the CU campus. Data Collection method: Static Method for SmarTone Cell Change Method for Peoples

20. Principle of the two data collection methods Static Method Wait for a sufficiently long period of time at a specific point in the 2D map to see the strength and stability of a cell strength. Determine the location ID and cell ID of that specific location after observing for a period of time

21. Principle of the two data collection methods Cell Change Method Walk around the campus and find the “boundaries” of different cells When cell change occurs we note down the change and try to find out the boundaries of the cells

22. Advantages and Disadvantages of the Two Methods Static Method: Accurate at those specific point Experiment only done on a set of specific points selected from the 2D map Takes a longer time Cannot figure out the cell boundary clearly unless those sample points are dense enough

23. Advantages and Disadvantages of the Two Methods Cell Change Method: Most of the cell boundaries can be detected Can discover different overlapping of cells Use less time Boundaries detected are “regions” instead of sharp lines

24. Expectations We expected: GSM Cells are of similar size Only small overlapped region at the cell boundaries No large cell completely covering a smaller cell Can be modeled as hexagonal shape covering the area.

25. Experimental Result For Peoples

26. Experimental Result

27. For SmarTone Experimental Result

29. Inconsistencies with Our Expectations Cells vary greatly in size and shape Large scale of cell overlap Some marco-cell encapsulating smaller micro-cells Cells may change shapes under different environment condition at different time Cells in CU are too large to get an accurate location of the mobile device

30. Conclusion on the Experiment Potential difficulties in 2D Space ID-to-location map drawn not accurate enough Cannot locate the location of a mobile device to an acceptable accuracy owing to the large size of cells Hierarchy of cells make it even harder to locate your current position

31. The Idea of Cell IDs in 1D Space Owing to the difficulties and inaccuracy of the detection of cell ID in 2-dimensional space, we turn to the 1-dimensional space Only travel in one direction Concentrate on the Entrance of a region Limitation in 1D space helps to ease the inaccuracy.

32. Cell IDs in 1D Space Location: [50] Cell ID: [1] Location: [50] Cell ID: [2] Location: [50] Cell ID: [3] Location: [50] Cell ID: [4] Cell ID: [1->2]Cell ID: [2->3]

33. MTRTraveller for Stations in Subway Apply to traffic route MTRTraveller - tell user the station arrival Initial Observation: Between two stations in subway, there is exactly one change This event can tell user that you are going from one station to another station Due to the shape of antenna in these stations Station 2Station 1 Cell ID Changes Here

34. MTRTraveller for Stations in Open Area KCR Stations in open area Many cell IDs in between two stations A station platform may also involve multiple cells Transition pair => in between S1 and S2 Station cell => in the station platform Station Cells: [S1, O], [S1, B] Transition Pairs: [S1, S2, O], [S1, S2, B], [S1, S2, P], [S1, S2, G] Station 2 Station 1 Station Cells: [S1, O], [S1, B], [S1, P]

35. MTR Cell ID Data Peoples

36. KCR Cell ID Data Peoples

37. MTR Cell ID Data SmarTone

38. KCR Cell ID Data SmarTone

39. MTR Cell ID Data Sunday

40. Statistics Time of ‘station arrival’ event occurrence before entering that station Should be enough for user to figure out the change Entering station in open area

41. Demonstration Map data, station data, transition data Movie in actual stations Simulation

42. Potential Problems All cell data depends on cell deployment Cannot control time to tell user the event of station arrival Problem occurred if two or more stations share the same cell ID Up-to-date cell information required Developers - collect data regularly  Automatic cell information collection kit Users - update their data regularly  Convenient update using SMS / GPRS

43. More to Improve… Personalize Informative Fancy user interface Distributed intelligence

44. Other Possible Applications Bus route All bus stops are in open area Tram route for tourism Just tell tourists that they are in a particular district (e.g. Causeway Bay, Wan Chai)

45. Other Possible Applications Detection of car speed detectors Make use of inaccuracy of GSM cell More data have to be stored I am caught! Oh, there is speed detector!

46. Future Work Automatic cell information collection kit Improvement on MTRTraveller Personalization User Interface Informative Distributed intelligence Generic middleware/library for developers Other applications

47. Conclusion Symbian OS for mobile phones GSM provides location-related information Using GSM cell information in Symbian program Not accurate enough for positioning Easily available for ordinary mobile phones Pure cell ID detection VS cell ID change event Design special applications mastering these information MTRTraveller Other applications

48. End of Presentation Thank you very much!