Interoperability Between Machine-to-Machine Communication System and IP Multimedia Subsystem - Interoperability and Open-Source Solutions for the Internet of Things - page 109

In [ 15 ], the authors researched similar concept to the one described in this
paper. They also considered IMS as possible solution for establishing a cost-
ecient and inter-active video connections between the dorbell and a user's
mobile terminal. The paper focuses mainly on different IMS standardized mech-
anisms like presence, supplementary subscriber services or policy control to real-
ize the service that works in dependence to various conditions. For example,
mixture of three different IMS subscriber services: call forwarding conditional,
presence and call notification, were used to route incoming video calls to different
users (house residents) on different locations (home or abroad) under different
conditions (busy on meeting or free). In their case, IMS is triggered every time
and IMS supplementary services were used to make the services more flexible. In
our paper, we researched one scenario when users are at home and when there
is no need to trigger IMS and no need to consume IMS resources while second
scenario when the user are not at home M2M system used IMS to establish a
video call which is not possible with the research in [ 15 ].
6UeCe
A use case for interworking between M2M and IMS would be smart home appli-
cation for home security: User has an intercom camera/speaker/mic with bell
button installed at the front door, intercom terminal and alarm inside the home
indicating when user is at home or not. When user is at home (alarm is off) and
somebody is at the door, the user at home on the intercom terminal sees via
the intercom camera who is the person at the door and can talk to the person
and/or open the door. This part is achieved as pure M2M service - video service
(see Fig. 5 ). The nodes in M2M system are communicating with HTTP proto-
col. The M2M device, terminal at the door, sends a messsage to M2M gateway
that the door bell button is pushed. The M2M application in M2M gateway is
responsible for logic and it communicates with M2M intercom terminal inside
the home. The M2M device inside the home plays a sound. If a user at home
pushes the answer button on M2M device (intercom terminal) inside the home,
the video session starts between M2M devices (dotted arrow in Fig. 5 ). That
session is executed in the local network and does not need to use IMS.
When the user is out of home, complex M2M service using the IMS system is
triggered with SIP protocol (see Fig. 6 ). When the IMS User Agent application
(UAA) at home indicates that there is nobody at home (alarm is off), it triggers
registering IMS user agent (UA) in M2M gateway. The IMS UA, inside UAA,
gets registered and authenticated in IMS system. The whole process is described
as follows (Fig. 7 )[ 2 ]:
1 Alarm application updates (UPDATE) GSCL data that alarm is tur-
ned on.
2 GSCL accepts update and respond with STATUS-OK.
3 GSCL notifies IMS User Agent Application (UAA), which is subscribed
to alarm status data, that alarm is on.