According to this figure, for a heterogeneous network, the internet of things access point
oers three communications types such as Ethernet, Wi-Fi, and ZigBee. Using this access point,
it is possible to establish a home network which can control and manage the home devices
where the ZigBee protocol is used. Subsequently, by using the embedded ZigBee agent in the
internet of things access point, the local and remote users can manage and control the home
devices from ZigBee by getting the required access right.
In the figure, the paper sheds light about how the internet of things access point is devel-
oped where it utilizes the embedded ZigBee agent with the existing Wi-Fi access point. The
remote users can use the developed ZigBee agent for controlling the devices from ZigBee,
establishing a connection with the internet.
For the ZigBee agent, the IoT access point gets an installation of the UPnP Device
Management Module. With the integration of this module, information can be broadcasted
of the ZigBee devices with the network and they can establish wireless connections with each
other.
Additionally, the UPnP protocol can be used to find out the ZigBee devices by the remote
handheld devices. There are five modules in the ZigBee agent. Suppose a user is away from home
and wishes to manage their ZigBee devices at home by using either the Wi-Fi or Ethernet to send
commands with the IoT access point. To read and write functions with the USB dongles of ZigBee,
the Serial Port Control Module can be used.
When the internet of things access point gets a user command, the Command Process Module
forwards it with the Serial Port Control Module. The Serial Port Control Module oers functions
to the Command Process Module for the exchange and execution of the ZigBee transceiver com-
mands. Subsequently, the Command Process Module receives the command from the Device
Management Module to fetch the ZigBee devices information and sends it to the HTTP Command
Process Module and the UPnP Device Management Module.
In case a user uses the HTTP protocol to send the command, that command is executed
first by the HTTP Command Process Module and results are returned in order to fetch the
information from the ZigBee devices. According to the above figure, the negotiation function
for the usage of channels is implemented by the Channel Allocation Module. Moreover, the
power saving mode of the ZigBee network is changed to the emergency mode by the Emergency
Process Module. This boosts up the sensors’ opportunities for the reporting of data readings.
System Implementation
Between the ZigBee device and a USB transceiver, an intermediary device role is played by the
ZigBee agent. The connection between the ZigBee device and agent is facilitated on the internet
for users through the control service of ZigBee. The paper mentions the use of embedded Linux
to install the RT3052 development board for the development of ZigBee agent. Consider the
following figure.
This diagram presents the ZigBee agent’s system architecture; it is composed of several
modules which include the ZigBee Device Management Module, HTTP Command Process
Module, Serial Port Control Module, the UPnP Device Management Module, Emergency Pro-
cess Module, and the Channel Allocation Module. What these modules do is described below.
Serial Port Control Module
This module is used for the reading and writing functionalities while working with the
Command Process Module. The primary module objective is the creation of the USB serial port
for the Linux OS (operating system).
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According to the paper, a ZigBee USB dongle helps the communication with other devices
by using the ZigBee transceiver. The FTDI FT232R is the chip which is used for communication.
Going by the code of Linux-2.6.21, you can configure its FTDI drivers while working with the
kernel of Linux. In case the internet of things access point is connected with a USB transceiver,
then an indication informs the detection of USB.
The paper uses an open-source library to manage the serial port control; you can easily
download it from the internet. The objective of the library is to turn on the 8N1 configura-
tion in the serial port. It also provides support for read and write functions in the serial port
for the Linux and Windows operating system. The library also helps to establish communica-
tion between the ZigBee transceiver and the Serial Port Control Module. Hence, the serial port
can be used for working with commands which can send and receive functions with the HTTP
Command Process Module and the Command Process Module.
Client
UPnP
Control Point
HTTP
POST,GET
ZigBee Device Information
ZigBee Agent
HTTP POST GoForm
GoAhead Web Server
ASP
JavaScript
Command Response
HTTP Command
Process Module
CGI
Launcher
HTML
Device
Information
ZigBee Device
Management
Module
UPnP Device
Management
Module
SSL
Command Request
Command Request/Response
Command Process Module
Command Write
Command Read
Serial Port Control Module
Command
Command
Command
ZigBee
Dongle
FTDI FT232R USB Driver
ZigBee
Device
UPnP Device Discovery
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Command Process Module
The ZigBee agent receives dierent requirements from a streaming command which is sent
by a ZigBee transceiver. When the Command Process Module gets the command from the
ZigBee module, it transfers it for execution to the corresponding module. The Simple Home
Net Company is the owner of the ZigBee transceiver. It oers support for dierent ZigBee
devices command.
ZigBee Device Management Module
In order to facilitate the ZigBee agent for management of dierent ZigBee devices at the same
time, the ZigBee Device Management Module receives and manages the Command Process
Module user commands. Going by these commands, information is collected by the model
in terms of the relevant ZigBee devices and is converted into a certain format of streaming
with various fields. Subsequently, the HTTP Command Process Module and the UPnP Device
Management Module receive management information from the ZigBee Device Management
Module.
In order to ensure that the aforementioned features are implemented, the module requires
the completion of three goals. For starters, to make sure for getting ecient ZigBee device man-
agement, the module requires the stipulation of a data structure which can help each ZigBee
device to store the management information.
Manufacturer
Device Type ID
IEEE Address
Device Nam
e
Network Address
cat web/ZigBeeDevice
#
#
#
#
#
#
#
‘‘
Info.zigbee
SimplHomeNet 0009 00158d0000140457 0001 ZEMP 1ug15!
Consider the above diagram in which the network address, the returned commands, the
device identified, the IEEE address, the device name etc are among the stored information. The
IEEE address refers to the distinct number which is given to all the ZigBee devices for identifi-
cation purposes.
If this module gets a new IEEE address, then what this means is that the local network was
joined by a new ZigBee device. In such an instance, the module begins to gather and accumulate
the new ZigBee device’s information.
Secondly, for maintenance purposes, the existing ZigBee devices are continuously accessed
by this module. In case, the module finds out that a certain ZigBee device has ceased to exist, it
will eliminate itself from the list of maintenance.
Thirdly, if a command result is returned by the Command Process Module, like “on” or
“o”, to read a ZigBee device status, then this result is either stored or updated within the infor-
mation of the device. Lastly, the HTTP Command Process Module gets the record.
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UPnP Device Management Module
The UPnP Device Management Module implements the UPnP protocol for the information
broadcasting to all those ZigBee devices which are on the network. This helps remote indi-
viduals in finding out the ZigBee devices. Moreover, they can also assist with the ZigBee device
control accesses.
The UPnP Forum proposed a service discovery protocol in the form of UPnP. The primary
objective of it is to power the connection of dierent devices so they can build connections with
each other in a home network. In order to do this, an UPnP device control protocol was released
by the UPnP forum. This protocol is founded on internet communication network protocol
standard.
There are three components in the UPnP protocol: the control point, the service, and the
device.
Media Request
User
Media Server
Media Stream
Server (Media Stream)
Device (Media Server)
Control Point
According to this figure, the UPnP devices are controlled via a smartphone. Early on, the
UPnP application by the name of UPnP CP is installed in the smartphone. This application is
used to control the devices running UPnP. For such cases, the UPnP device serves as a media
server which oers to stream for the command execution with the CP.
When a multimedia server detects a smartphone, a request is made for media streaming.
There are five fundamental steps for the UPnP streaming: Discovery, Description, Control,
Event Notification, and Presentation.
Beginning with the Discovery step, the smartphone control point uses the SSDP protocol
for broadcasting its service. When the network is joined by the control point, the UPnP devices
are able to find the UPnP equipment in the network.
For the Description step, the XML method is used by the UPnP device to send informa-
tion (serial number, brand, manufacturer name, and nickname), control, service list, event, and
other necessary data which is used by the manufacturer.
In the Control step, the UPnP device gets a control message from the CP and then the
equipment is managed according to the contents of the message. For the Event Notification
step, a service is subscribed by the control point. As the status of the device is updated, the
control point receives a message from the service in the XML format.
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For the Presentation step, the control can be allowed to get the status of the device or its
control via a web page. Considering the above-mentioned protocols, the UPnP Forums apply
a standardization of dierent devices like multimedia servers and printers. It is important to
note here that not all the ZigBee devices are able to establish a connection with the standardized
devices. Hence, the paper makes use of the UPnP protocol for the broadcasting of the ZigBee
devices.
In order to find out the UPnP devices, the paper used an open-source portable UPnP library
to implement the UPnP Device Management. In this module, the ZigBee Device Management
Module sends information to the ZigBee device. Subsequently, it stores the ZigBee device infor-
mation with the UPnP device and converts it into the description file of the UPnP device after
which the information is broadcasted by the ZigBee device. Hence, the remote user can easily
use the description file to find out the UPnP device.
Source: https://www.researchgate.net/publication/287406143_Design_and_Implementation_of_
an_IoT_Access_Point_for_Smart_Home
In this figure, the file has the device ID, network address, IEEE address, GoAhead web server
port, URL, and ZigBee device information. Hence, whenever it senses the removal of a ZigBee
device, it deletes the corresponding UPnP device. The use of the above-mentioned method can
help the module to handle the UPnP devices and help the remote users in finding the ZigBee
devices via the UPnP protocol.
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