Context-Aware Applications - Guide to Cloud Computing for Business and Technology Managers - page 515

be especially used for indoor navigation, like in a museum. If the
position is not determined automatically, it can be also specified
manually by the user.
4. Service and application provider : The service provider offers a number
of different services to the user and is responsible for the service
request processing. Such services offer the calculation of the posi-
tion, finding a route, searching yellow pages with respect to posi-
tion, or searching specific information on objects of the user interest
(e.g., a bird in wild life park).
5. Data and content provider : Service providers will usually not store
and maintain all the information that can be requested by users.
Therefore, geographic base data and location information data will
usually be requested from the maintaining authority (e.g., mapping
agencies) or business and industry partners (e.g., yellow pages, traf-
fic companies).
Based on the information delivery method, we identify three types of LBS:
pull, push, and tracking services. In the case of a pull service, the user
issues a request in order to be automatically positioned and to access the
LBS he or she wants. A use-case scenario demonstrating a pull service
is the following. A tourist roams in a foreign city and wants to receive
information about the nearest restaurants to his or her current location.
Using a mobile device, the tourist issues an appropriate request (e.g., via
SMS [short message service] or WAP [wireless application protocol]), and
the network locates his or her current position and responds with a list of
restaurants located near it. On the contrary, in the case of a push service,
the request is issued by the service provider and not the user. A repre-
sentative example of push services is location-based advertising, which
informs users about products of their interest located at nearby stores. In
this service, users submit their shopping preference profiles to the service
provider and allow the provider to locate and contact them with adver-
tisements, discounts, and/or e-coupons for products of interest at nearby
stores. So, in this case, the service provider is the one who pushes informa-
tion to the user. Finally, in a tracking service, the basic idea is that some-
one (user or service) issues a request to locate other mobile stations (users,
vehicles, fleets, etc.).
From a technological point of view, LBSs are split into two major cat-
egories depending on the positioning approach they use to locate mobile
stations. There is the handset-based approach and the network-based
approach. The former approach requires the mobile device to actively par-
ticipate in the determination of its position, while the latter relies solely
on the positioning capabilities of elements belonging to the mobile net-
work. For both of these approaches, several positioning techniques have
been developed or are under development. What distinguish them from