location

Location-based service

A location-based service (LBS) is an information and entertainment service, accessible with mobile devices through the mobile network and utilizing the ability to make use of the geographical position of the mobile device. LBS services include services to identify a location of a person or object, such as discovering the nearest banking cash machine or the whereabouts of a friend or employee. LBS services include parcel tracking and vehicle tracking services. They include personalized weather services and even location-based games. They are an example of telecommunication convergence.

This concept of location based systems is not compliant with the standardized concept of real time locating systems and related local services (RTLS), as noted in ISO/IEC 19762-5 and ISO/IEC 24730-1.

History

The first LBS services were launched commercially in Japan by KDDI in 2001. The first book to discuss location-based services was Services for UMTS by Ahonen & Barrett (editors) in 2002. Mobile handset makers have tended to take 'upstream initiative' to embed LBS in their mobile equipment. Originally, LBS was developed by mobile carriers in partnership with mobile content providers.

The main advantage is that mobile users don't have to manually specify ZIP codes or other location identifiers to use LBS, when they roam into a different location. GPS tracking is a major ingredient for making it possible, utilizing access to mobile web.

Locating methods

Sometimes referred to as positioning, with control plane locating the service provider gets the location based on the radio signal delay of the closest cell-phone towers (for phones without GPS features) which can be quite slow as it uses the 'voice control' channel. In the UK, networks do not use trilateration; LBS services use a single base station, with a 'radius' of inaccuracy, to determine a phone's location. This technique was the basis of the E-911 mandate and is still used to locate cellphones as a safety measure. Newer phones and PDAs typically have an integrated A-GPS chip.

In order to provide a successful LBS technology the following factors must be met:

Coordinates accuracy requirements that are determined by the relevant service;
Lowest possible cost;
Minimal impact on network and equipment.

Several categories of methods can be used to find the location of the subscriber. The simple and standard solution is GPS-based LBS. It is used to maintain knowledge of the exact location, however can be expensive for the end-user, as they would have to invest in a GPS-equipped handset. GPS is based on the concept of trilateration, a basic geometric principle that allows finding one location if one knows its distance from other, already known locations.

GSM localization is the second option. Finding the location of a mobile device in relation to its cell site is another way to find out the location of an object or a person. It relies on various means of multilateration of the signal from cell sites serving a mobile phone. The geographical position of the device is found out through various techniques like time difference of arrival {TDOA} or Enhanced Observed Time Difference (E-OTD).

Another example is Near LBS (NLBS), in which local-range technologies such as Bluetooth, WLAN, infrared and/or RFID technologies are used to match devices to nearby services. This application allows a person to access information based on their surroundings; especially suitable for using inside closed premises, restricted/ regional areas.

Anoter alternative is an operator- and GPS-independent location service based on access into the deep level telecoms network (SS7). This solution enables accurate and quick determination of geographical coordinates of mobile phone numbers by providing operator-independent location data and works also for handsets that are not GPS-enabled.

LBS applications

Some examples of location-based services are:

Requesting the nearest business or service, such as an ATM or restaurant
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

For the carrier, location-based services provide added value by enabling services such as:

Resource tracking with dynamic distribution. Taxis, service people, rental equipment, doctors, fleet scheduling.
Resource tracking. Objects without privacy controls, using passive sensors or RF tags, such as packages and train boxcars.
Finding someone or something. Person by skill (doctor), business directory, navigation, weather, traffic, room schedules, stolen phone, emergency calls.
Proximity-based notification (push or pull). Targeted advertising, buddy list, common profile matching (dating), automatic airport check-in.
Proximity-based actuation (push or pull). Payment based upon proximity (EZ pass, toll watch).

In the U.S. the FCC requires that all carriers meet certain criteria for supporting location-based services (FCC 94-102). The mandate requires 95% of handsets to resolve within 300 meters for network-based tracking (e.g. triangulation) and 150 meters for handset-based tracking (e.g. GPS). This can be especially useful when dialling an emergency telephone number - such as enhanced 9-1-1 in North America, or 112 in Europe - so that the operator can dispatch emergency services such as Emergency Medical Services, police or firefighters to the correct location. Companies such as Rave Wireless in New York are using GPS and triangulation to enable college students to notify campus police when they are in trouble.

Mobile messaging

Mobile messaging plays an essential role in LBS. Messaging, especially SMS, has been used in combination with various LBS applications, such as location-based mobile advertising. SMS is still the main technology carrying mobile advertising / marketing campaigns to mobile phones. A classic examples of LBS applications using SMS is the delivery of mobile coupons or discounts to mobile subscribers who are near to advertising restaurants, cafes, movie theatres. The Singaporean mobile operator MobileOne has carried out such an initiative in 2007 that involved many local marketers, what was reported to be a huge success in terms of subscriber acceptance.

Examples of companies offering location-based messaging (sometimes referred to as 'geo-messaging') are Loopt (US), Dodgeball (US) and GeoMe (Spain).

Privacy issues

With the passing of the Can Spam Act in 2005, it became illegal in the United States to send any message to the end user without the end user specifically opting-in. This put an additional challenge on LBS applications as far as 'carrier-centric' services were concerned. As a result, there has been a focus on user-centric location-based services and applications which give the user control of the experience, typically by opting in first via a website or mobile interface (such as SMS, mobile Web, and Java/BREW applications).

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.