IEEE Consumer Electronics Magazine - November/December 2020 - 64

Consumer Electronics Communications

lists the association among the devices. The
groups section lists the groups in a simulated
HAS. The ChangeCoordinator section lists the
time at which the primary coordinator needs to
be replaced, the time is in seconds, and the simtime section lists the total duration of simulation
in seconds. In the simulation configuration file,
ChangeCoordinator section is optional. In our
current simulator implementation devices, such
as switch, dimmer, and door lock handler send
commands at a random time intervals.
We ran a simulation using the configuration
file shown in Figure 6. Our simulator creates the
following ZigBee devices: seven lights, six
switches, one door lock, one door lock handler,
one dimmer, and one dimmable light. The simulator creates associations between the following
devices: 1) switch 1 $ light 1, 2) switch 2 $ light
2, 3) doorhandler 1 $ doorlock 1, and 4) dimmer
1 $ dimmablelight 1. The first group section in
the configuration file creates a group among
switch 3, light 3, and light 4. In this particular
group configuration, switch 3 controls both light
3 and light 4. Similarly, there are other groups
sections in the file that create groups of different
smart home devices. The ChangeCoordinator
section instructs the simulator to change the primary network coordinator at 900 s. Hence, at 900
simulation seconds, our HAS proxy will automatically on-board the existing devices onto a new
network coordinator. The simtime section
instructs the simulator to end the simulation
after 2000 s. At the end of the simulation, the
simulator outputs the number of control packets
and data packets exchanged in the network.
The number of data packets exchanged in the
network in the presence of our HAS proxy was
exactly two times the number of packets
exchanged when there was no HAS proxy in the
HAS. This is due to the fact that each device is onboarded onto our HAS proxy; therefore, devices
send their packets to our proxy, which relays the
messages to the primary network coordinator
and vice versa. The introduction of a HAS proxy
results in relatively higher data activity in the network; however, it is manageable for the following
reasons: 1) packets exchanged between HAS
proxy and primary network coordinator can take
place on a separate communication channel; 2)
1x extra messages are exchanged between the

proxy and primary coordinator, and no extra
messages are transmitted by the smart devices;
hence, their power consumption with and without our proxy device is the same; and 3) our
proxy device and primary network coordinator
are mains powered; hence, extra power consumption by these devices is not an issue. It is
also important to note here that when a primary
network coordinator is replaced, the number of
control messages exchanged to on-board already
existing devices onto the new coordinator is
same with and without our HAS proxy; however,
the proxy eliminates the need to manually onboard all end devices on the new coordinator.

CONCLUSIONS

We presented a HAS proxy and accompanying
methods to avoid network recommissioning when
either an existing network coordinator malfunctions or a user switches to a new network service
provider. In such an event, our proxy can seamlessly on-board existing devices onto the new coordinator. Hence, it avoids a tedious manual onboarding process. Moreover, it also achieves seamless communication between devices through the
primary coordinator. To accomplish its functionality, the proxy maintains a device mapping data
structure and backs-up the data structure in the
cloud as well. In case the proxy malfunctions, a
new proxy can fetch the data from the cloud and
the network becomes operational again straight
away. We have evaluated the approach in a Java
simulator that can simulate a ZigBee-based HAS
along with the functionality of our proxy.

ACKNOWLEDGMENTS

This work was supported by the Science
Foundation Ireland under Grant 13/RC/2077.

& REFERENCES
1. "ZigBee cluster library specification," [Online].
Available: http://www.zigbee.org/wp-content/uploads/
2014/10/07-5123-06-zigbee-clus ter-libraryspecification.pdf, Accessed on: Jun. 6, 2020.
2. "Z-Wave protocol overview," [Online]. Available:
https://wiki.ase.tut.fi/courseWiki/images/9/94/
SDS10243_2_Z_Wave_Protoc ol_Overview.pdf,
Accessed on: Jun. 6, 2020.

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http://www.zigbee.org/wp-content/uploads/2014/10/07-5123-06-zigbee-clus ter-library-specification.pdf http://www.zigbee.org/wp-content/uploads/2014/10/07-5123-06-zigbee-clus ter-library-specification.pdf http://www.zigbee.org/wp-content/uploads/2014/10/07-5123-06-zigbee-clus ter-library-specification.pdf https://wiki.ase.tut.fi/courseWiki/images/9/94/SDS10243_2_Z_Wave_Protoc ol_Overview.pdf https://wiki.ase.tut.fi/courseWiki/images/9/94/SDS10243_2_Z_Wave_Protoc ol_Overview.pdf

IEEE Consumer Electronics Magazine - November/December 2020

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