Location-Based Services Using GSM Cell Information over Symbian OS

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Location-Based Services Using GSM Cell Information

over Symbian OS

Final Year ProjectLYU0301

Mok Ming Fai (mfmok1)Lee Kwok Chau (leekc1)

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Agenda

Project Motivation Work Review Middleware for LBS Developers

Application Programming Interface (API) Development Toolkit

Sample Application Conclusion

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Motivation

The need of LBS emerges We would like to provide LBS with minimum

hardware requirement Symbian phones support retrieving location

information via GSM modem Using GSM cell information to approximate

current location. Provide a set of development tools for rapid

LBS development

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Previous Work

In the previous semester, Written software to collect GSM cell information Collected cell information in CU Campus and alon

g the rails Concluded the accuracy 2D space is not good en

ough Migrated to 1D path which provide a better accura

cy Built MTR Traveller to illustrate the accuracy that

we could achieve.

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LBS Application Development

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Middleware

Current issues: Developers are required to put a great effort in the

whole development process Service is usually the main focus The proposed method is applicable in different

fields, but not just MTR / KCR route Different developers have different requirements

to meet There is a great desire to have middleware.

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Overview of Middleware Architecture

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Definition – Reference Point

Reference point: Place taken as a reference on target path in the cell data collection process (e.g. bus stop, railway stations)

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Definition – Point of Interest

Point of Interest (POI): Location that is interested in the application level (e.g. building, tourist spot)

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API Design

Retrieving location information involves complex system calls

Wrap low level system calls into high level function calls

Make development process more efficient

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API Design

Two major functions required in LBS: Perform a particular action upon encountering

specific set of cell change event Search for nearest POI related to current

reference point

CNetworkInfo

CProximityCLocationListener

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API Design

Three components in API package: CNetworkInfo

Connect to GSM Modem Retrieve location information

Operating System and GSM modem

CNetworkInfo

User Application

Complex function calls are handled

Simple function calls, requesting the action of hardware modem

Location information returns when available

Retrieve current location information

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API Components

CLocationListener Keep track of cell change events Perform specific action upon entering specific cells

Cell B

Cell D

Cell E

Cell A

Cell B

Cell C

Cell D

Action performsat these transitions

Action not performed, since they are not listed

Cell changes to be kept tracked

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API Components

CProximity Read in a location defini

tion file Search for nearest POI

relative to current reference point

Current Location

Points-of-interest, for example, restaurants

Nearest POI relative to current location

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Software Development Kit

It consists of software tools for reducing time spent on application development, providing developer with maximum convenience

Components include: Cell Snap – cell data collection Cell Analyzer – cell data processing Distance Mapper – nearest cell searching AppGen – LBS application generation

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Cell Data Collection and Processing

API focuses on easy cell data manipulation Data collection has to be done manually Multiple network operators and routes

involved Cell data has to be processed and optimized

before use Cell Snap and Cell Analyzer are introduced

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Cell Snap

Collection of cell data was done manually in the past Cell Snap - a tool for automated cell data collection Different reference points can also be captured by

phone camera

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Need of Data Processing

Cell Snap output is designed to be read by human Formatted cell data for machine

Photos and data output are separated, so developers have to map cell data and reference point on their own Better presentation of cell data to developers

Cell Snap data is just raw data Data editing tool and automated data analysis

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Cell Analyzer

Cell Analyzer provides developers with a user-friendly environment to edit and process cell data for further use

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Features of Cell Analyzer

It has the following features: Data processing:

Data format transform Better cell data presentation to developers Manual cell data editing Data combination for multiple operators

Automated data optimization: Cell duplicate removal Clear classification between reference points

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Cell Data in Tree Representation

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Cell Analyzer in Action

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Need of Reference Point Classification

There is a need to clearly classify between two reference points so that the application accurately can tell users that they enter a new reference point

Two pieces of information can be concluded through cell data at any moment: “You are in the station” “You are in the way from station X to station Y”

This is handled by Cell Analyzer automatically

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Open Area Problem in MTR Traveller

Stations in open area in MTR Traveller

Station Cells:

[S1, O], [S1, B]

Transition Pairs:

[S1, S2, O, B], [S1, S2, B, P], [S1, S2, P, G]

Station 2Station 1

Cell ID: O

[S1, O] => in Station 1

Cell ID: OB[S1, B] => in

Station 1

Cell ID: BP[S1, S2, B, P] => on the

way of S1S2

Cell ID: PG[S1, S2, P, G] => on the

way of S1S2

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Handling by Cell Analyzer

Both reference points X and Y contain a node of cell 1

Cell 1 really tells user that they are in Y Cell Analyzer simply removes cell 1 from

reference point X

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Distance Mapper

To provide searching function, we need a location definition file

Distance Mapper let users to map those POI onto a physical map

It reads in the file generated by Cell Analyzer

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Distance Mapper

It calculate the logical distance among all POIs in pixel domain

After the calculation, it outputs a location definition files which is used by the LBS application

(15,63)

100

94

75

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62

75

(15,201)

(24,17)

(23, 4522)

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Application Generation

The previous tools mentioned enable developers to have a nice LBS application development environment

LBS application often focuses also on content and service, including actions upon cell changes and information provided

Points of interest (e.g. tourist spots) should also be considered instead of just reference points (e.g. bus stops)

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AppGen

AppGen is specifically designed for content builders by generating source code for a LBS application

General developers may also use source code as a starting point to build their own application

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Options Provided in AppGen General

Map displayed Icon Message format

Reference Point Location on the map

Point of Interest Name Description Image Path to POI from a

reference point

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Application in Action (1)

Reference Points

Points of Interest

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Application in Action (2)

1. User selects adestination

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Application in Action (3)

2. User is at the startingpoint of a route

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Application in Action (4)

3. The application keepstrack of the location of theuser in the path at eachreference point

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Application in Action (5)

4. Display the informationabout the point of interest(destination)

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MTR Traveller Remake

Development Process Cell data collection by Cell Snap Cell data processing by Cell Analyzer Application generation by AppGen

Advantages Short development time: 1.5 week VS < 8 hours f

or multiple operators Easy to be extended (e.g. new stations coming int

o service)

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CU Campus Bus Route Guide

It is another complete LBS application to illustrate the ease of development with the middleware

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Flow of LBS Application Development through Middleware

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Three Development Streams

Low-level developers would like to work on GSM cell ID and even optimize the underlying mechanism and algorithm to suit their application needs

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Three Development Streams

General application developers would need a set of tools to facilitate cell data collection, analysis and distance measurement on a given map.

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Three Development Streams

Content builders would focus on how a location-based service is offered through content editing and enrichment rather than creating an application from stretch

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Trade-off of Applying Middleware

AppGen Distance Mapper

Cell Snap & Cell Analyzer

LBS Application Development Interface(API)

GSM Modem and NetworkAccess cell information

Work with low-level APIs

Generate LBS application

Facilitate location assignment to cell

for searching nearest cell

Flexibility

Convenience

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Conclusion

We have developed a new approach in providing location-based service using mobile phone only

Accuracy in 1D space can be fairly accurate

We have developed a set of development tools to simplify LBS development process.

Created several LBS application using the development tools to test its completeness

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Thank you!

Q & A session