Being more precisely it is not so easy to create an

Being more precisely, it is not so easy to create an efficient
implementation. And geo-fences could be connected also
with another hot LBS area – indoor positioning. From the
practical point of view both systems mostly interested due to
high commercial promising – deliver commercial offering
here and right now.
II. I
MPLEMENTATIONS
Now let us see what we have from the practical point of
view. Conceptually, geo-fences approach is quite
transparent. The principles and model are simple. We have
to have some definitions for the areas, e.g. as two pairs of
geo-coordinates (latitude, longitude) values. They are
defining some square (Nord West – South East). For this
square (squares) we can define some notification message
(messages). So, as soon as our mobile user (subscriber or
user enabled our service is in (or out, or in/out – depends on
the rules) he will get that message. As we can see, the basic
problems here are how to check user’s location against some
predefined geo boundaries and where this checking should
be performed.
The location of the user can be easily derived by various
positioning technologies like GPS or Cell. We can
determine the location of a user while he is active in a
service session, or we can organize some form of continous
monitoring. For latter form the user needs to be continuously
tracked in the background, even when the mobile device is
idle or executes other applications [2].
One method for positioning is often not enough. So, in the
most cases mobile phones can use some combinations, e.g.
Assited GPS (A-GPS). A-GPS uses assistance data received
from the network to obtain a faster location calculation
compared with GPS alone. The positioning data can be
exchanged between the phone and the network over either
the control channel (control plane) or the user channel (user
plane) plane. A control plane implementation uses a
dedicated control channel. This approach could be used used
for emergency services (e.g., 911 in the US). For non-critical
location-based application user plane could be used. The
main difference is the the significant network overhead in
case of the dedicated control channel [3]. It is so called
Secure User Plane (SUPL). With SUPL positioning data is
sent over the user’s traffic channel using a secure IP
connection between the smartphone (in standard is is called
SET - SUPL enabled Terminal) and SUPL Location
GeoFence services
Dmitry Namiot

Platform (SPL) on the network side. It was developed by the
Open Mobile Alliance (OMA) [4]. The objective of the
SUPL enabler is to provide an industry standard framework
for positioning over the User Plane as an alternative to
existing control plane solutions, which are bandwidth-
constrained and limited to access types that are part of the
control plane system. User Plane may comprise IP and SMS
bearers in the mobile networks environment and IP bearers
in the WLAN/Internet environment. This mechanism could
be implemented in a wide range of contexts (i.e. a controlled
mobile network operator’s environment or an open
Internet/WLAN environment).