01-04-2011, 03:38 PM
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TRACKING AND POSITIONING OF MOBILES IN TELECOMMUNICATION
INTRODUCTION:
Mobile positioning technology has become an important area of research, for emergency as well as for commercial services. Mobile positioning in cellular networks will provide several services such as, locating stolen mobiles, emergency calls, different billing tariffs depending on where the call is originated, and methods to predict the user movement inside a region. The evolution to location-dependent services and applications in wireless systems continues to require the development of more accurate and reliable mobile positioning technologies. The major challenge to accurate location estimation is in creating techniques that yield acceptable performance when the direct path from the transmitter to the receiver is intermittently blocked. This is the Non-Line-Of-Sight (NLOS) problem, and it is known to be a major source of error since it systematically causes mobile to appear farther away from the base station (BS) than it actually is, thereby increasing the positioning error.
In this a simple method for mobile telephone tracking and positioning with high accuracy, the location of a mobile telephone by drawing a plurality of circles with the radii being the distances between a mobile telephone and a several base stations (it will be found using Time Of Arrival (TOA)) and the base stations at their centers, and using location tracking curves connecting the intersection points between each circle pair instead of the common chords defined by the circles. Using location tracking curves,connecting the intersection points of the two circles which will be drawn by ordinary TOA method, instead of the common chord as in TDOA.
REVIEW TO MOBILE TECHNOLOGY :
Configuration of a typical mobile telecommunication network.
The mobile telecommunication network includes a several base stations (BSs) T 1 to T N for providing mobile telecommunication service to a mobile subscriber through a mobile telephone M1, a base station controller (BSC) for controlling the BSs T 1 to T N, and a mobile telephone switching office (MTSO) for connecting the BSC to another BTS or a PSTN (Public Switched Telephone Network). In a cellular mobile telecommunication network, the whole service area is divided into a several coverage areas having respective base stations (BS). Each BS coverage area is called a "cell." Each BS is provided with a frequency of a range between 450 to900 MHz. More than one cells can use same frequency. Only condition is that no two adjacent cells must have same frequencies. An MTSO controls these BSs so that a subscriber can continue his call without interruption while moving between different cells. The MTSO can reduce the time required for calling a subscriber by locating the cell of the subscriber. In case of an emergency like a fire, or a patient needing first aid treatment, the mobile subscriber should be accurately located. Tracking the location of a mobile subscriber within the boundary of a cell in a mobile telecommunication network is known as "location based services Mobile technology includes mainly two functions. They are call fixing and hands-off process. All the BSs are sending a signal of power 25 to 30w to the mobile unit. When a user switches ON his mobile, it will search for the strongest signal and got connected to that BS. Then the mobile unit sends an identification signal to the BS. When he fixes a call, the BS accepts the request and sends the request to the BSC and MTSO. Then the MTSO will searches where the subscriber is and connects the call.
When a user moves to another cell the MTSO will change the frequency allotted to it and allots the frequency of the new BS.For both these processes GEOLOCATION of the mobile unit is essential.
NEED FOR GEOLOCATION:
One of the most powerful ways to personalize mobile services is based on location. The location based services, provides the subscribers very best of the service. Recent demands from new applications require positioning capabilities of mobile telephones or other devices. The ability to obtain the geo-location of the Mobile Telephone (MT) in the cellular system allows the network operators to facilitate new services to the mobile users. The most immediate motivation for the cellular system to provide MT position is enhanced in accident emergency services. The geolocation of the mobile user could provide services like
• Emergency service for subscriber safety.
• Location sensitive billing.
• Cellular Fraud detection.
• Intelligent transport system services.
• Efficient and effective network performance and management.
ARCHITECTURE OF A GEOLOCATION SYSTEM:
In order to fix a call the subscriber we are calling must be located accurately. A geolocation service provider provides location information and location aware services to subscribers.
Upon a request from a subscriber for location information about an MS, the service provider will contact a location control center querying it for the coordinates of the MS. This subscriber could be a commercial subscriber desiring to track a mobile device. The location control center will gather information required to compute the MS’s location. This information could be parameters such as received signal strength, BTS ID, TOA of signals, and so on that we discuss later. Depending on past information about the MS, a set of BS’s could be used to page the MS, and directly or indirectly obtain the location parameters. These are sometimes called Geolocation base stations (GBSs). Once this information is collected, the location control center can determine the location of the mobile with certain accuracy and convey this information to the service provider. The service provider will then use this information to visually display the MS’s location to the subscriber. Sometimes the subscriber could be the MS itself, in which case the messaging and architecture will be simplified, especially if the application involves self-positioning.
TECHNOLOGIES USED FOR GEOLOCATION:
1. GPS based Cell Phone Tracking(HANDSET BASED)
2. GSM based Cell Phone Tracking(NETWORK BASED)
3. HYBRID
4. DIRECTION BASED GEOLOCATION
• GPS BASED:
GPS-based technology requires the installation of client software on the handset to determine its location for emergency purposes. This technique determines the location of the handset by computing its location by cell identification, signal strengths of the home and neighboring cells, which is continuously sent to the carrier. In addition, if the handset is also equipped with GPS then significantly more precise location information is then sent from the handset to the carrier.
It requires the active cooperation of the mobile subscriber as well as software that must be able to handle the different operating systems of the handsets. Typically, smart phones, such as one based on Symbian, Windows Mobile , iPhone / iPhone OS, or Android, would be able to run such software. The key disadvantage of this technique (from mobile operator's point of view) is the necessity of installing software on the handset and others are as follows
• Increases the price and the size of the mobile telephone.
• The load on the mobile telephone is increased.
• Power consumption is high.
Global positioning system
EXAMPLES:
Zentek Electronics & Communication Pvt Ltd (Mumbai) :Zentek is a vehicle tracking solution provider & manufacturer of gps vehicle tracking & complete fleet tracking.
Airsys Safety Solutions (P) Ltd(Hyderabad): Provides vehicle tracking systems in Hyderabad .
• GSM based Cell Phone Tracking:
GSM cell phones' technology works based on small, equal, and adjacent areas. Each area is termed a "cell". An entire region covered by a service provider contains several such cells. This may lead to corrupt data when the cell phone is on or near the border of two adjacent "cells" – creating intersection of data over two different signals: a small disadvantage of GSM based cell phone tracking.
On the other hand, as you receive continuous information from the service provider about the cell where the phone is travelling, much calculation need not be performed for tracking cell phones. If the cell phone is on roaming, the computations will be little more complex as you have to consider the base (home cell) and then determine the "cell" or area where the cell phone is roaming.Network-based techniques utilize the service provider's network infrastructure to identify the location of the handset. The advantage of network-based techniques (from mobile operator's point of view) is that they can be implemented non-intrusively, without affecting the handsets.
The accuracy of network-based techniques varies, with cell identification as the least accurate and triangulation as the most accurate. The accuracy of network-based techniques is closely dependent on the concentration of base station cells, with urban environments achieving the highest possible accuracy.
One of the key challenges of network-based techniques is the requirement to work closely with the service provider, as it entails the installation of hardware and software within the operator's infrastructure.
EXAMPLES:
AIRCEL,AIRTEL,IDEA, RELIANCLE,TATA and VODAFONE are some Indian companies which provide 2G based services using GSM technology.
• HYBRID :
Hybrid positioning systems are systems for finding the location of a mobile device using several different positioning technologies. Usually GPS (Global Positioning System) is one major component of such systems, combined with cell tower signals, wireless internet signals, Bluetooth sensors or other local Positioning Systems.
These systems are specifically designed to overcome the limitations of GPS, which is very exact in open areas, but works poorly indoors or between tall buildings (the urban canyon effect). By comparison, cell tower signals are not hindered by buildings or bad weather, but usually provide less precise positioning. Wi-Fi signals may give very exact positioning, but only in urban areas with high Wi-Fi density - and depend on a comprehensive database of Wi-Fi access points.
EXAMPLE:
Skyhook’s Core Engine is a software-only location system that quickly determines device location with 10 to 20 meter accuracy. It is presently implemented in USA .
• DIRECTION BASED GEOLOCATION:
ANGLE OF ARRIVAL METHOD in this there will be transmission and reception of signals between the mobile unit and BSs. This method calculates the angle of arrival of signal receiving at the BS. When a mobile user switches the system ON it receives the signal from different base stations, may be 3 or 4 or more. The angle of arrival method two or more base station for the determination. It measures the direction of signal falling on the base station and measures the angle of incidence with respect to a normal and determines the position of the system. Angle of arrival method is not an accurate method used for the mobile positioning because of its some disadvantages such as:
• The determination of the system will be in error if the angle of incidence is changed due to any obstacle like atmospheric particles or due to scattering etc.
• The accurate location cannot be determined if the mobile user is in between the BSs, that is in a straight line.
• It cannot be used for the indoor environments.
TRACKING AND POSITIONING OF MOBILES IN TELECOMMUNICATION
INTRODUCTION:
Mobile positioning technology has become an important area of research, for emergency as well as for commercial services. Mobile positioning in cellular networks will provide several services such as, locating stolen mobiles, emergency calls, different billing tariffs depending on where the call is originated, and methods to predict the user movement inside a region. The evolution to location-dependent services and applications in wireless systems continues to require the development of more accurate and reliable mobile positioning technologies. The major challenge to accurate location estimation is in creating techniques that yield acceptable performance when the direct path from the transmitter to the receiver is intermittently blocked. This is the Non-Line-Of-Sight (NLOS) problem, and it is known to be a major source of error since it systematically causes mobile to appear farther away from the base station (BS) than it actually is, thereby increasing the positioning error.
In this a simple method for mobile telephone tracking and positioning with high accuracy, the location of a mobile telephone by drawing a plurality of circles with the radii being the distances between a mobile telephone and a several base stations (it will be found using Time Of Arrival (TOA)) and the base stations at their centers, and using location tracking curves connecting the intersection points between each circle pair instead of the common chords defined by the circles. Using location tracking curves,connecting the intersection points of the two circles which will be drawn by ordinary TOA method, instead of the common chord as in TDOA.
REVIEW TO MOBILE TECHNOLOGY :
Configuration of a typical mobile telecommunication network.
The mobile telecommunication network includes a several base stations (BSs) T 1 to T N for providing mobile telecommunication service to a mobile subscriber through a mobile telephone M1, a base station controller (BSC) for controlling the BSs T 1 to T N, and a mobile telephone switching office (MTSO) for connecting the BSC to another BTS or a PSTN (Public Switched Telephone Network). In a cellular mobile telecommunication network, the whole service area is divided into a several coverage areas having respective base stations (BS). Each BS coverage area is called a "cell." Each BS is provided with a frequency of a range between 450 to900 MHz. More than one cells can use same frequency. Only condition is that no two adjacent cells must have same frequencies. An MTSO controls these BSs so that a subscriber can continue his call without interruption while moving between different cells. The MTSO can reduce the time required for calling a subscriber by locating the cell of the subscriber. In case of an emergency like a fire, or a patient needing first aid treatment, the mobile subscriber should be accurately located. Tracking the location of a mobile subscriber within the boundary of a cell in a mobile telecommunication network is known as "location based services Mobile technology includes mainly two functions. They are call fixing and hands-off process. All the BSs are sending a signal of power 25 to 30w to the mobile unit. When a user switches ON his mobile, it will search for the strongest signal and got connected to that BS. Then the mobile unit sends an identification signal to the BS. When he fixes a call, the BS accepts the request and sends the request to the BSC and MTSO. Then the MTSO will searches where the subscriber is and connects the call.
When a user moves to another cell the MTSO will change the frequency allotted to it and allots the frequency of the new BS.For both these processes GEOLOCATION of the mobile unit is essential.
NEED FOR GEOLOCATION:
One of the most powerful ways to personalize mobile services is based on location. The location based services, provides the subscribers very best of the service. Recent demands from new applications require positioning capabilities of mobile telephones or other devices. The ability to obtain the geo-location of the Mobile Telephone (MT) in the cellular system allows the network operators to facilitate new services to the mobile users. The most immediate motivation for the cellular system to provide MT position is enhanced in accident emergency services. The geolocation of the mobile user could provide services like
• Emergency service for subscriber safety.
• Location sensitive billing.
• Cellular Fraud detection.
• Intelligent transport system services.
• Efficient and effective network performance and management.
ARCHITECTURE OF A GEOLOCATION SYSTEM:
In order to fix a call the subscriber we are calling must be located accurately. A geolocation service provider provides location information and location aware services to subscribers.
Upon a request from a subscriber for location information about an MS, the service provider will contact a location control center querying it for the coordinates of the MS. This subscriber could be a commercial subscriber desiring to track a mobile device. The location control center will gather information required to compute the MS’s location. This information could be parameters such as received signal strength, BTS ID, TOA of signals, and so on that we discuss later. Depending on past information about the MS, a set of BS’s could be used to page the MS, and directly or indirectly obtain the location parameters. These are sometimes called Geolocation base stations (GBSs). Once this information is collected, the location control center can determine the location of the mobile with certain accuracy and convey this information to the service provider. The service provider will then use this information to visually display the MS’s location to the subscriber. Sometimes the subscriber could be the MS itself, in which case the messaging and architecture will be simplified, especially if the application involves self-positioning.
TECHNOLOGIES USED FOR GEOLOCATION:
1. GPS based Cell Phone Tracking(HANDSET BASED)
2. GSM based Cell Phone Tracking(NETWORK BASED)
3. HYBRID
4. DIRECTION BASED GEOLOCATION
• GPS BASED:
GPS-based technology requires the installation of client software on the handset to determine its location for emergency purposes. This technique determines the location of the handset by computing its location by cell identification, signal strengths of the home and neighboring cells, which is continuously sent to the carrier. In addition, if the handset is also equipped with GPS then significantly more precise location information is then sent from the handset to the carrier.
It requires the active cooperation of the mobile subscriber as well as software that must be able to handle the different operating systems of the handsets. Typically, smart phones, such as one based on Symbian, Windows Mobile , iPhone / iPhone OS, or Android, would be able to run such software. The key disadvantage of this technique (from mobile operator's point of view) is the necessity of installing software on the handset and others are as follows
• Increases the price and the size of the mobile telephone.
• The load on the mobile telephone is increased.
• Power consumption is high.
Global positioning system
EXAMPLES:
Zentek Electronics & Communication Pvt Ltd (Mumbai) :Zentek is a vehicle tracking solution provider & manufacturer of gps vehicle tracking & complete fleet tracking.
Airsys Safety Solutions (P) Ltd(Hyderabad): Provides vehicle tracking systems in Hyderabad .
• GSM based Cell Phone Tracking:
GSM cell phones' technology works based on small, equal, and adjacent areas. Each area is termed a "cell". An entire region covered by a service provider contains several such cells. This may lead to corrupt data when the cell phone is on or near the border of two adjacent "cells" – creating intersection of data over two different signals: a small disadvantage of GSM based cell phone tracking.
On the other hand, as you receive continuous information from the service provider about the cell where the phone is travelling, much calculation need not be performed for tracking cell phones. If the cell phone is on roaming, the computations will be little more complex as you have to consider the base (home cell) and then determine the "cell" or area where the cell phone is roaming.Network-based techniques utilize the service provider's network infrastructure to identify the location of the handset. The advantage of network-based techniques (from mobile operator's point of view) is that they can be implemented non-intrusively, without affecting the handsets.
The accuracy of network-based techniques varies, with cell identification as the least accurate and triangulation as the most accurate. The accuracy of network-based techniques is closely dependent on the concentration of base station cells, with urban environments achieving the highest possible accuracy.
One of the key challenges of network-based techniques is the requirement to work closely with the service provider, as it entails the installation of hardware and software within the operator's infrastructure.
EXAMPLES:
AIRCEL,AIRTEL,IDEA, RELIANCLE,TATA and VODAFONE are some Indian companies which provide 2G based services using GSM technology.
• HYBRID :
Hybrid positioning systems are systems for finding the location of a mobile device using several different positioning technologies. Usually GPS (Global Positioning System) is one major component of such systems, combined with cell tower signals, wireless internet signals, Bluetooth sensors or other local Positioning Systems.
These systems are specifically designed to overcome the limitations of GPS, which is very exact in open areas, but works poorly indoors or between tall buildings (the urban canyon effect). By comparison, cell tower signals are not hindered by buildings or bad weather, but usually provide less precise positioning. Wi-Fi signals may give very exact positioning, but only in urban areas with high Wi-Fi density - and depend on a comprehensive database of Wi-Fi access points.
EXAMPLE:
Skyhook’s Core Engine is a software-only location system that quickly determines device location with 10 to 20 meter accuracy. It is presently implemented in USA .
• DIRECTION BASED GEOLOCATION:
ANGLE OF ARRIVAL METHOD in this there will be transmission and reception of signals between the mobile unit and BSs. This method calculates the angle of arrival of signal receiving at the BS. When a mobile user switches the system ON it receives the signal from different base stations, may be 3 or 4 or more. The angle of arrival method two or more base station for the determination. It measures the direction of signal falling on the base station and measures the angle of incidence with respect to a normal and determines the position of the system. Angle of arrival method is not an accurate method used for the mobile positioning because of its some disadvantages such as:
• The determination of the system will be in error if the angle of incidence is changed due to any obstacle like atmospheric particles or due to scattering etc.
• The accurate location cannot be determined if the mobile user is in between the BSs, that is in a straight line.
• It cannot be used for the indoor environments.
