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During last few years mobile phones has increased many folds in several countries and in some countries the mobile phone system is ready to overtake conventional fixed lines. “Being mobile” is one of the most important reasons for the exponential growth of mobile phones. Location in a mobile network is always a very strong component of “mobility. A rapid growth in Location Determination Technologies (LDT's) in recent years has given rise to possibility of precisely locating a mobile phone. This makes a new set of wireless application called “Location Based Services” (LBS). Various location specific questions can be answered if the precise location of the mobile object is known at a given time: “Where am I?” “How do I reach the nearest location. These positioning techniques give the means to locate subscriber when someone initiates a request. For example, the subscriber initiates a request - where is my hotel located? The subscriber need not enter an address, because with location determination technology, the network will automatically locate him/her and a send map to the mobile device showing the location of the hotel. During this time of telecommunications competition, mobile network operators continuously produce new and innovative ideas to create differentiation and increase profits. One of the best ways to do accomplish this is through the delivery of highly personalized services. One of the most powerful ways to personalize mobile services is based on location. Faced with an increasingly difficult challenge in growing the numbers of subscribers, wireless carriers and their partners are developing a host of new products, services, and business models based on data services. Location services, which provide information specific to a location, are a key part of this portfolio.
3. TECHNOLOGY BEHIND THE CONCEPT:
Location in mobile network Based Services exploit knowledge about where a mobile device and its user are located. This location knowledge is used to provide relevant, contextual information to users. A result of the convergence of information systems, (wireless) communication mechanisms and positioning technologies, Location Based Services offer a personalised approach to data access.
The concept behind LBS is location determination technologies (LDT's). These are used to estimate subscribers' location based upon terrestrial or satellite-based (like the Global Positioning System or GPS) technologies.
By using the information obtained from the determination systems of certain location, a Location Platforms is established ,which then compares the location of mobile device against the map content database to find or search addresses, our interests points etc. It also has software tools which are determine the travel direction, predictive traffic analysis and position/address matching, etc.
The concept of location based systems is not compliant with the standardized. Concept of real time locating systems and related local services (RTLS),.Though there are technological and infrastructure constraints currently holding back the growth of the LBS provision, these are likely to get resolved in due course of time, given the moves in the international arena. But the concern in the Indian context is that the mobile industry market structure as determined through policy and regulation has not favoured the growth of competition and innovation in value added services such as LBS.
Location based services:
· Public safety or emergency services:
Since the location of the subscriber can be provided by the carrier, the mobile phone is a valuable access point in the times of emergency. In the US, Europe and Japan, it is mandatory by law for carriers to be able to provide such information.
· Consumer services:
- Navigation: Users get route maps to a particular destination, real time traffic routing that takes into account actual congestion patterns etc.
- Location based advertising: Advertisements of discounts or offers from a store as the user comes within the vicinity.
- Location based reminders: Users can enter in to-do lists, whose location information activated when the user passes by; for instance, pick up shopping or laundry etc.
- Family and friend finder: Allows users to keep track of the location of their children relatives or friends, with the informed consent of these subscribers.
- Location based search: Allows users to access local services, or find even more.
- Location based mobile gaming: which began a decade ago has larger scope now as positioning and handset technology have improved considerably.
· Enterprise services :
LBS enables firms in fleet and asset tracking, field service dispatching, route and delivery optimization, and mobile workforce management. This has proved extremely useful for small and medium businesses. For instance, Metro Transportation Services, a company providing ground transportation services in the US, achieved a 30 percent increase in productivity and 10 percent reduction in accidents using Nextel's location-based service.
· Privacy issues with these services:3
Privacy is a very important issue in location-based services. As a user decides what applications are allowed to receive his location. These applications are previously registered in user's user preferences..Once the location-based service receives the HTTP request from WES (Web Sphere Every place Server), privacy checks are performed. A check is made to determine if the requested application is a location-based application. Additionally, a check is made to determine if the application is allowed to receive user's location. If all checks are returned positive, the location-based service sends the XML request to a mobile location provider (MLP) to find user's location. One implication of this technology is that data about a subscriber's location and historical movements is owned and controlled by the network operators, including mobile carriers and mobile content providers.
· Three core technologies of location based services:
It is based on three core technologies: mobile devices, wireless networking and locating sensing.
Location-based experiences can be delivered through a wide variety of mobile devices. Commercial products range from high-specification laptop computers, to personal digital assistants (PDAs), through to mobile phones. They vary greatly in terms of computing power, display size, form factor, portability and battery life. Previous attempts to classify such devices include the IEEE's distinction between mobile devices (including phones and PDAs, which are essentially small enough to fit into a pocket), and larger devices such as laptops that are classed as portable (IEEE, 2002). However, emerging devices such as mobile gaming consoles and future developments such as wearable computing may soon challenge such classifications. As noted previously, perhaps the key technology to watch here is the mobile phone, both because it is so widespread and also because mobiles are beginning to emerge as genuine computing devices (for example, high-end phones can now support simple 3D graphics).
Another interesting technology to watch is mobile game consoles, with major players in the mobile phone and/or gaming markets releasing innovative mobile consoles (e.g. Nokia's nGage and Sony's forthcoming Personal Playstation), and other interesting new devices such as the Gizmondo, which supports inbuilt GPS positioning. At the very cheap end of the market, even Tamagotchi now have basic peer-to-peer communication facilities for multiplayer use.
While there is a wide range of wireless networking that might be used to deliver location-based experiences to mobile participants, three broad classes of technology seem likely to dominate the field in the immediate future: cellular telephony, Wireless Ethernet and Bluetooth. Cellular telephony itself refers to a wide range of technologies that share the common goal of supporting commercial mobile telephone services. These include the most established but low bandwidth technologies of GSM and SMS as well as more recent, higher-bandwidth (but lower coverage) protocols such as GPRS (2.5G) and now 3G. The defining feature of these technologies is that they are commercial services provided by operating companies, meaning that users and their organisers do not have to provide or manage the core infrastructure but they do have to pay for data transfer. Of course, they are also the networking protocols of choice for mobile phones.
The third core technology is location sensing (or more generally, context sensing). Once again, there is a very wide variety of technologies available, many of which were reviewed in detail in a previous Tech Watch report . The following briefly summarises the most significant approaches.
The Global Positioning System (GPS) enables a mobile receiver to triangulate time-of-flight of transmissions from multiple orbiting satellites in order to compute its location above the Earth's surface. The appeal of GPS is the potential to track the user's position across a wide geographical area, potentially to within a few metres (or even better with some variants of GPS). In practice however, while GPS has enjoyed great success in relatively constrained and predictable situations such as vehicle navigation, early attempts to use it as part of coherent location-based experiences indicate some of its frailties, especially coverage and accuracy, that vary with both location and time-of-day, especially in built-up urban environments.
4. STRUCTURE NEEDED FOR THE SYSTEM:
The most important technology used in LBS provision is the positioning technology, which determines the accuracy of location. Various methods which are present today are:
- Cell of origin: It is the most basic and cheapest method is to use the location of the radio base station to which cell phone is connected. The location can be determined within 0.5 km in urban areas and 35 kms in rural areas.
- Time of arrival: In this we use the time it takes for a signal to move from the cell phone to the base station that it is connected to. The accuracy of this method is higher and for high number of location measurement scales; there are some additional costs of implementation.
- Angle of arrival: The angles at which a signal arrives at two base stations are calculated and then some triangulation is done to determine the location of the user. In urban areas, buildings cause reflection and hindrance in the signals due to which accuracy can be affected by this method.
- Enhanced observed time difference (E-OTD): cell phone with this capability measure the time difference between neighbouring synchronized base stations. For this method location of the base station should be known. This method is best for 100 to 300 metres.
- Assisted GPS (or A-GPS): The latest technology that integrates the mobile network with the GPS to give a better accuracy of 5 to 10 meters. This system fixes the position within seconds, has better coverage and can in some cases be used indoors, consumes less power and requires fewer satellites. The disadvantage to date has been the cost of A-GPS enabled handsets for the user but this issue has been tackled by operators and handset manufacturers recently.
5. LOCATION MANAGEMENT:
The growth of mobility aspects in cellular networks occurs at three different levels. First, there is spatial level, that is, users desire to roam with a mobile terminal. Second, growth occurs from the penetration rate of mobile radio access lines. Third the traffic generated by each wireless user is constantly growing. On one hand cellular adhoc subscriber use their mobile terminals, on the other hand more capacity-greedy services like multimedia services, internet accesses arrive one after another. From this consideration, the generalized mobility features will have serious impact on the wireless telecommunication networks. Mobility can be categorized into two areas.
- Radio mobility, which mainly consist of the handover process.
- N/w mobility, which mainly consists of location management
Location updating and paging:
The main task of location management is to keep tracks of the user's current location, so that an incoming message can be routed to mobile station (MS). Location management schemes are essentially based on user's mobility and incoming call rate characteristic. The n/w mobility method has to face strong antagonism between its two basic procedures: 1. Updating (or registration) the process by which a mobile endpoint initiates a change in the location database according to its new location; and 2. Finding (or paging), the process by which the network initiates a query for an endpoint's location (this result in the update of location database). The location updating procedure allows the system to keep the user's location knowledge, more or less accurately, in order to be able him or her, in case of an incoming call, for example location updating is also used to bring the user's service profile near its location and allows the network to rapidly provide the user with his or her services. The paging process achieved by the system consists of sending paging message in all cells where the mobile terminal could be located. Most location management techniques use a combination of updating and finding in an effort to select the best trade-off between update overhead and delay incurred in finding. Specially, updates are not usually sent every time an endpoint enters a new cell, but rather are sent according to a predefined strategy such that the finding operation can be restricted to a specific area.
There are three mobility models, namely fluid flow model, the random-walk model, and the gravity model are addressed. The fluid flow model considers traffic flow as the flow of fluid, modelling, macroscopic movement behaviour. The random -walk model describes individual movement behaviour. It is also applied to regions of varying sizes, from city mobility models to national and international mobility models. Mobility traces indicate current movement behaviour of users and are more realistic than mobility models.
In a cellular n/w, location tracking mechanism may be perceived as updating and querying as distributed database i.e. location database of endpoint identifier-to-address mappings. Location tracking has two components: (1) determining when and how a change in a location database entry should be initiated and (2) organizing and maintaining the location data base. In cellular n/w, endpoint mobility within a cell is transparent to the network, and hence location tracking is only required when an endpoint moves from one cell to another. The location-tracking methods are broadly classified into two groups. The first group includes all methods based on algorithms and n/w architecture, mainly on the processing capabilities of the system. The section group contain the methods based on learning process, which require the collection of statistic on subscriber mobility's behaviour for instance. This type of method emphasizes the information capabilities of the network.
Radio Resource Management:
The problem of radio resource management is one important issue or good network performance. The radio resource management problem depends on the three allocation decisions that are concerned with channels, base station, and with the transmitter powers. Both channel derivation and allocation methods will influence the performance. The use of TDMA and CDMA are alternative to FDMAused in the first-generation systems. With TDMA, the usage of each radio channel is partitioned into time slots, and each user is assigned a specific frequency and timeslot combination. Thus, only a single mobile in a given cell is using a given frequency at any particular time. With CDMA multiple mobiles in a given cell use a frequency channel simultaneously, and the signals are distinguished by spreading them with different codes. The channel allocation is an essential feature in cellular networks and impacts the networks performance.
6. PROBLEM WITH LOCATION IN MOBILE NETWORK BASED SERVICES:
Present wireless location based services are growing at slower rate. The major problem is the inefficiency of geographic coordinates such as longitude/latitude and UTM. Coordinates for the location based services requires more than 20 characters at a resolution of meters that are difficult for people to remember and communicate. Consumers remain using the traditional addresses and place names to access location based services. Such addresses and place names are long character strings that sometimes require foreign characters that can't be directly feed on a mobile phone key pad. These wide variations of address formats make it impossible to develop reliable algorithms to handle all addresses, which results in frequent failures in handling addresses.
HOW TO SOLVE THESE PROBLEMS?
All these problems can be solved by the Natural Area Coding System. This article proposed five wireless location based services enhanced with the Natural Area Coding System:
- Universal Address lookup service
- GPS enhanced cell phone
- Wireless driving directions service
- Wireless map service
- Wireless location based search service
Some example of location based services:
- Turn by turn navigation to any address
- Locating people on a map displayed on the mobile phone.
- Receiving alerts, such as notification of a sale on gas or warning of a traffic jam.
- Location-based mobile advertising.
There is wide range of services which rely on users location information have been conceived, although the mark used to filter access to many types of geographical information services (GIS). There are many which are not yet mature. The main point is to remember that location is simply a useful bit of data can be used to filter access to many types of geographical information services There are many exploit location in order to provide more relevant information, or to generate new services. It can be powerful when added to other user profile information to offer personalized and location sensitive responses to customers. Van de Kar and Bouwman (2001) distinguish between emergency services, mobile network operator services, and value-added services (VAS), focusing on the latter category as the primary e-commerce opportunity. In the VAS category, they describe a number of different service areas, including information, entertainment, communication, transaction, mobile office and business process support services. During 2000 Levijoki offers a simpler categorization scheme, distinguishing b/w billing, safety, information, and tracking and proximity services. D.Roza and Bilchev (2003) demonstrate services into two broad categories: first one are requested by users once their location is determined, and other one are triggered automatically once a certain condition is met (e.g. boundary is crossed). We might consider the former set to be “pull” services and the latter to “push” services. In addition, D. Roza and Bilchev (2003) identify five groups of application areas: communication, fleet management, routing, safety and security, and entertainment. Services can also classify according to whether they apply to consumer business customers, or employees in a firm. Some of the most commonly discussed services are described below:
Emergency safety and medical health care services:
As noted earlier, many governments are moving to require cellular operators to develop the capability to automatically identify subscribers' locations in the event of an emergency. This data would then be forwarded to the appropriate public safety answering point (PSAP) to coordinate the dispatch of emergency personnel. These are not necessarily revenue producing services in their own right, but it is possible to conceive of medical and safety services that would be offered on a commercial basis, particularly if LBS were combined with telemedicine techniques that would allow physiological data to be transmitted back to health care providers.
Mobile users can be provided with a wide range of localized information. Weather forecasts, tourist attractions, landmarks, restaurants, gas stations, repair shops, ATM locations, theatres, public transportation options (including schedules) are just a few examples of the types of information that would be more useful if filtered by the user's location. Gazetteer services link current and historic geographic names to spatial data. More sophisticated services will depend on the development of richer geographical information systems. For example, a query about local theatres might be extended to focus only on those playing a specific movie. Or, rather than look for particular types of businesses, a customer may input a specific product, and ask for all businesses in the area that carry it. If the database includes other product
information, such as prices and other terms, then real time comparison shopping may be feasible en route or even inside stores.
In addition to identifying the location of various destinations, location-based services can also be employed to guide users along the best routes. Automobile manufacturers are already offering services such as GM's On star, using vehicle-based GPS receivers and mapping/route guide services in selected cars. Collectively these types of services are often referred to as telemetric services and automatic vehicle location services by the automotive companies. If integrated with real time traffic data, such route guide services may also make routes contingent on current traffic conditions.
Transaction and billing:
Cellular operators are beginning to offer different rates based on the location of callers (e.g. in a designated home area). E-commerce services might include use of the wireless device to make payments for tickets at theatres and on public transportation, vending machines, and for goods in shops to speed up check outs. Often this capability requires that wireless devices exchange payment information with local POS devices. In the US, for example, a company called Merchant Wired is putting wireless LANs into shopping malls so that small stores can have this capability.
Asset training and fleet management:
Location services can be used to track the locations of people, pets, objects, vehicles, etc. Trucking companies are putting in their own systems, for example, that not only track the location of vehicles, but also the contents inside delivery trucks using an onboard wireless LAN. Last minute delivery changes can be made based on truck inventory and location, enhancing efficiency and customer service. Tracking can also be combined with navigation services to help with route optimization for deliveries. Tracking services can also aid in preventing theft of valuable items, and even in locating people.
Many applications are targeted to employees that are out of their offices. In general, these will be internal information systems applications, but may involve partnering with location-based service providers for their implementation. Some applications have to do with the provision of location sensitive information, such as updates or changes to customer account information when field representatives are in proximity to specific customers. Given the limited screen space of mobile units, even emails might be filtered so that only those that re critical or relevant would be forwarded to a field agent, while others remain on the server. Scheduling applications might also take into account the location of workers
There are many possibilities for location-specific entertainment services using a mobile device. One of the more well-known location services now in use is a game called Bo t-Fighters, developed the gaming company It's Alive and offered by Telia Mobile (Norris, 2003).In this game, subscribers use the location determination capability of the network and SMS messages sent from their mobile phones to locate and “shoot” imaginary robots (other players). They must be close enough to the target to be able to “hit” them. New versions using Java-equipped handsets have even more functionality, and the game is spreading to other markets like the UK (Norris, 2003). Other entertainment applications that have been discussed
include dating services, DJ requests in clubs, person-to-person messaging in a closed setting like a concert..
Another category that overlaps with many of the above application areas is that of proximity services. These services inform users when they are within a certain distance of other people, businesses, or other things. Examples include those discussed in the information category, such as when users are informed ofthe closest desired business (e.g. in response to queries about the closest gas station or ATM), or the Bot-Fighter game mentioned under entertainment. Other services have been introduced based on knowledge of the proximity to other mobile devices (and, hence, the people that are carrying them). For example, NTT DoCoMo offers a “friend's finder” service on its iMode system (Levijoki, 2000). Users predefine which friends are allowed to know their location.
8. CHALLENGES AND DEVELOPMENT:
Future of the location based service industry shows the state of immaturity. The extensive work in the computer science community on pervasive and context -aware computing further suggest that future system will incorporate more than location information and data drawn from personal
Location-based experiences are in their infancy and the technologies on which they build are diverse and still maturing. Unsurprisingly, significant challenges need to be addressed before they reach their potential. In particular, it is important to be aware of the limitations of the technologies involved.
Dealing with uncertainty of location sensing:
All of the location-sensing technologies mentioned previously introduce considerable uncertainty - far more than traditional input technologies such as keyboards and mice, which tend to be precise and predictable. These uncertainties include limited coverage, accuracy and often considerable variation of performance over both space and time. Early studies of location-based experiences have shown how these uncertainties can have a profound impact on the user's experience (Crabtree et al., 2004). Consequently, researchers in human-computer interaction have begun to articulate the design challenges that have to be met, for example, Bellotti's ‘five questions' for sensing-based interfaces :
How do I address one (or more) of many possible devices?
How do I know the system is ready and attending to my actions?
How do I effect a meaningful action, control its extent and possibly specify
at a target or targets for my action?
How do I know the system is doing (has done) the right thing?
How do I avoid mistakes?”
Dealing with uncertainty of connection:
A second major source of uncertainty lies in wireless networking. It is highly likely that the user of an extended location-based experience is going to suffer from one or more periods of disconnection. Again, it may also make sense to reveal the state of the connection to the user, a technique already familiar from everyday mobile phones, which display an estimation of signal strength. It may also be important to provide some level of continued experience when disconnected, requiring designers to cache information on the user's mobile device (or at least guidance on how to get reconnected), even though its memory may be small. Finally, designers must anticipate potentially inconsistent information as users continue to interact with the local part of an experience while disconnected.
Privacy is perhaps the most significant long-term challenge facing the successful roll-out of location-based experiences. Monitoring a user's location and transmitting this to other users, or storing it centrally, has the potential to seriously compromise individual privacy. Solutions are likely to rely in a mixture of technical, social and perhaps even legal mechanisms. Technical mechanisms for handling privacy will involve the careful choice of location-sensing technologies (e.g. preferring those that run only on the user's local device), along with mechanisms for controlling disclosure, backed up with appropriate security mechanisms. Developing appropriate social mechanisms requires raising awareness of the privacy implications of location-based technologies through a close dialogue with users and/or their representative organisations. Legally, institutions will need to be aware of data protection and be increasingly aware of the implications for disclosure of location-based data under the Freedom of Information legislation.
- The potential widespread use of users' own mobile phones to take part in educational location-based experiences raises important issues in the area of management and billing. Users will most likely be responsible for administering their own devices (raising important issues of security), and where cellular telephony is used, may need to pay directly for each data transfer. Beyond this, there is a potential culture clash over the increasing use of mobile phones in an educational setting-mobile phones may be seen as problematic in environments such as schools and the use of personal communication devices in public settings can still be controversial.
- The demand for location-based services seems most likely to come from the student body, which will already be familiar with them from social and personal use. One organisational challenge is therefore to ‘educate the educators', helping university staff to become equally familiar with their potential. There are also social issues to be addressed concerning the relatively ad hoc and (from a central point of view) uncontrollable use of mobile communications, especially in formal situations such as lectures and examinations. These include dealing with interruptions, being aware of the potential of electronic side-chat (which might be seen by some as subversive), through to the more extreme possibility of cheating in examinations..
Our overview of mobile location-based networking services reveals that the market potential is thought to be significant, driven in part by the deployment of automatic location identification systems for emergency response. There are, however, significant barriers to overcome. Technological barriers result from the diversity and cost of approaches to location determination, creating a complex set of choices for operators and potential interoperability problems that, if unsolved, are likely to stifle development. There are many exciting services under development, and some have been operating successfully in such markets as Japan for several years. Innovative applications such as location-based games have achieved a following in Sweden and been introduced into other markets. Despite the promise of LBS for consumers, however, privacy concerns, quality of service problems, fair access to location information, and the lack of standards for technology and service providers may hinder market development and represent critical policy issues to be resolved. Finally, in the area of potential future directions, it is evident that location is merely a starting point for personalization and context-aware services that use other relevant information when constructing service offers. Moreover, the rapid deployment of alternative wireless technologies, such as Wireless Fidelity (WiFi or 802.11) is both a threat and an opportunity for cellular operators, and will likely shape the future development of location based services for mobile.