Home network message specification based on power line
communication and its application
D.S. Kim*, K.J.Myung*, W.H.Kwon* and H.J.Shin**
* School of Electrical Engineering, Seoul National University, Seoul, 151-742, Korea
Phone: +82-2-873-2279, Fax: +82-2-878-8933, E-mail: dskim@asri.snu.ac.kr
** DVN Team, DM Lab. LG Electronics Inc.
hjshin@lge.co.kr
Abstract: In this paper, a home network message specification based on Power Line Communication
(PLC) is proposed. As a case study, the home network message specification for white goods is
proposed. It is designed for the various home appliances from the lightning to white goods using
power line communication based on the web browsing protocol. The proposed home network system
is composed of the home network message specification, the middle ware interface and the embedded
system based on the PLC.
Keywords: Home Network Message Specification, Power Line Communication, Home Appliances
Introduction
Homes contain a number of complex electronic
products and electrical subsystems. The major
problem with subsystems in homes today is that
they do not communicate with each other and do
not share a common interface and information. To
be successful in the home network/home
automation, it must meet the several
requirements: the network plug and play, the selfconfiguration, the IP address assignment for home
appliance, the low cost cabling and the energy
management, and etc [1].
All home appliances are used by end-users, and
network initialization and configuration are
technical and professional works. So, the network
plug-and-play and the auto-configuration
technology have been required. In addition to, the
user-oriented application technology, the interoperability between various applications and API
in proper modeling and description, are
considerable. For satisfying these demands,
European Home Systems (EHS) Specification
have defined the way of electronic and electric
devices in and around a home can interact and
communicate with each other by European Home
System
Association
(EHSA)
[2].
The
specification of Energy Conservation & Health
Care Network (ECHONET) also has defined
middle-ware methodology and full protocol stack
to facilitate the development of applications [3].
As a case of white good's specification, the
Lonworks protocol specification has defined the
parts of the refrigerator function profiles. But, it
stands on the basis of services of the appliances.
So it is not the specification of appliances but the
definition of the display module of the
refrigerator [4]. In the CEbus (Consumer
Electronic bus) protocol, the context contains the
node control object and is present in all CEbus
compliant (or HomePnP) products [5]. As a
middle-ware technologies of home network,
Universal Plug and Play (UPnP)[6] have been
developed by Microsoft Cooperation, Jini have
been developed by Sun Microsystems.
For the interconnection with Internet, all white
goods and audio/video appliances demand IP
assignments respectively. So, recent studies have
been intensified on software and hardware
architecture for home network systems, in
particular, the internetworking architecture
between Internet and home network protocols as
like CEbus [8-11].
The low cost wiring (no rewiring) and energy
management is hot issue in home network/home
automation area. The realizations of an easy-touse, low-cost network system are important
factors for the implementing home network. By
these reasons, the PLC, the phone line
communication and the wireless communication
have been developed recently [12, 13, 14].
Among of them, the wireless communication of
course provides a solution to this problem connectivity anywhere [14]. Unfortunately, at the
present time, there are several competing
standards for home wireless networks and for
many consumers the cost is currently still
111
prohibitive. As another method, Electrical outlets
and the set of power lines provide an intriguing
solution - they are ubiquitous throughout the
home. To reduce cabling cost and easy
installation in home environment, the home
automation based on PLC has been developed
[15,16].
From now, there are no results about user
oriented home network message specification for
white goods and IP enabled the home network
system using PLC. Prior results are mainly
focused on the gateway system and the
interconnection between heterogeneous protocols
as like CEbus, X-10, IEEE1394, ATM [17,18,19].
In this paper, the Home Network Message
Specification (HNMS) based on the PLC is
proposed. As a case study, the message
specification of white goods is described. The
developed home network system on the PLC is to
allow the home appliance to communicate using
XML based browsing technology [5] and Java
based technology.

It should be able to give priority to
specific devices.

A home networking infrastructure to ties
up all devices together. This infrastructure must
be capable of carrying data, voice and
audio/video throughout home.

The system must work with both low
bandwidth and high bandwidth device.

The energy management must work with
the connected home appliance using power line
communication.
Home Network on PLC based Embedded
System(HOPES)
The proposed home network architecture
provides the ability to fully integrate and manage
all subsystem within a home and specifies a set of
APIs allowing developer to develop the
application for the home network.
This paper is organized as follows. In the next
section, the design consideration of the proposed
home network system is described. Section 3
gives overviews of the HNMS of white goods.
Section 4 explains the implemented test-bed.
Finally, the conclusion is presented in Section 5.
Design Consideration
The options in the home from a transport media
perspective fall into three categories: "partially
wired" (cable TV coax, phone-line twisted pair,
and data grade cabling such as CAT5), wireless,
and "existing wires" or power line. Among of
them, power line communication technology is a
powerful technology that meets many
requirements of home networks, especially in the
cost and future functionality as like energy
management, etc [20, 21,22]. For this reason, the
proposed system is considered to building TCP/IP
based network by using the existing AC power
lines already installed in any residence.
Fig.1 Structure of HOPES in Home
The HOPES architecture brings the power of
client-server computing to home network tools.
By using the services provided by the HOPES
architecture, power line nodes can be monitored
and controlled through home network. The
HNMS provides network services; it maintains
the network database, enables and coordinates
multiple points of access to its services and data.
White goods such as washing machines and
Heating Ventilating and Air conditioning (HVAC)
equipment have been required to connected to
Internet, each device for customer service and
energy management.
In Fig. 1, the home server has a Virtual Device
Service (VDS) same as the service which is
provided by controlled device. The home server
has all VDS which is supported by every devices
connected in the home networks. By using the

It should support a wide range of the information in the related VDS, the home server
home appliance from bandwidth consuming can respond to the outdoor requests to each
multimedia data to delay sensitive security device. device.
112
 Virtual Device Service (VDS): an abstract
representation of a specific set of resources and
functionality at a real home digital device.
 Device Specific Attribute (DSA): an attribute
mapping of the VDS to the physical and device
specific functional aspects of the real home
digital device
typedef struct VDS_info {
Home Network Message Specification
LS_State_changes_allowed,In general
LS_No_state_changes_allowed,
LS_Limited_services_permit,
} Logical_status;
The structure of VDS model is showed in Fig. 2.
For the device modeling, modeling group can be
divided by user interface, database and control
module. User interface module is made for the
convenience of end users. It is composed of the
device information, the GUI data, and etc. Data
base module is the data of domain and file
management.
Visible_string
vendor_name;
Visible_string
model_name;
Logical_status
vds_logical_status;
Physical_status
vds_physical_status;
Resource_list
list_of_action_service;
Resource_list
list_of_data_base;
Resource_list
list_of_variable_access_lists;
}VDS_info;
typedef enum Logical_status{
typedef enum Physical_status{
PS_Operational,
PS_Partially_operational,
PS_Inoperable,
PS_Needs_PowerOn;
} Physical_status;
The alarm model maps to the action service
object of HNMS using action notification service.
Specification of White Goods
Fig.2 HNMS VDS Model
From Table.1 to Table.3, variable access objects
for each white goods are described. For the
function profiles of white goods, products of 7
home appliance company were investigated and
analyzed. Table.1 shows the variable access
object of the air conditioner. They are composed
of variable name and data type. It will be
classified into service and device. The variables
object may be used to represent each detail device
and control variables for the developer. They
support services and functions for the end user.
The control variable, action set, and program
invocation are included by control module. Each
module has several objects and they include the
related variables and functions.
Table.2 shows the variables access object of
micro-oven. The variable object may be used to
represent each detail device and control for the
manufacturer as like Air conditioner.

Information Object: one or more data
elements that are referred to device information
elements that are referred to together by a single
name or description.

Data Base Object: an abstract object that
represents a subset of the capabilities of a VDS.

Action Service Object: an abstract object
representing a dynamic element that most closely
corresponds to an execution thread in a multitasking environment, composed of a set of
Domains.
Table.3 shows the variables of the washing
machine. They are also classified into service and
device. The variables object may be used to
represent each detail device and control for the
washing machine manufacturer. They support
variables for using the service and function for
the end user. In addition to the introduced
examples, the refrigerator, lightening, TV, audio
so are analyzed and documented also.
The syntax notation of VDS Information object is
defined as follows. It is composed of the product
information and the physical and logical status of
the device.
typedef struct DB_info {
Visible_string
data_base_name;
DB_State
state;
}DB_info;
typedef struct MO_DB_Data {
kindof_MO_Select
Select;
unsigned int
Temperature;
int
Humidity;
113
Name
Type
Type Description
enum {idle, cold_air,
clean_air, hot_air }
R/W
AC_Status
enum
AC_RoomTemperature
Int
R
AC_TargetTemperatureSet Int
W
AC_TargetTemperature
R
Int
R
AC_AirFource
enum
enum{low, medium,
high }
AC_AirFourceSet
enum
enum{low, medium,
high }
W
AC_AirUDDirection
Int
int(-90 ~ +90)
R
AC_AirUDDirectionSet
Int
int(-90 ~ +90)
W
AC_AirLFDirection
struct
struct { bool auto;
int LFdegree; }
R
AC_AirLFDirectionSet
struct
struct { bool auto;
int LFdegree; }
W
R
AC_Reservation
TimeSet
Time
W
AC_ReservationTime
Time
R
AC_CurrentTimeSet
Time
W
AC_CurrentTime
Time
R
.............
....
Name
Type
WM_MaterialSet
WM_Material
struct {
WM_WaterSupplySet Struct bool Hot_Water; //on,
off
bool { Cold_Water;//on,
struct
off } Hot_Water; //on,
WM_WaterSupply
Struct bool
off
bool Cold_Water; //on,
WM_WaterHeightSet Float off }
WM_WaterHeight
Float
WM_WashingMethod
Enum enum { auto, manual }
Set
WM_WashingMethod Enum enum { auto, manual }
struct {
WM_ReservationSet Struct bool Reservation;
time Time;
WM_method
method;}
struct {
WM_Reservation
Struct bool Reservation;
time Time;
WM_CurrentTimeSet Time WM_method method;}
WM_CurrentTime
.....
Category
enum
On/Off
R/W
MO_Status
enum
Run, Stop
R/W
MO_Door
enum
open, close
R/W
MO_Temperature
float
R
MO_TemperatureSet
float
W
MO_Start
boolean On
W
MO_Protection
enum
On/Off
R/W
MO_Warming
enum
On/Off
R/W
MO_WarmingTempera float
ture
MO_EndingAlarm
enum
On/Off
R/W
On/Off
R/W
MO_EconomicPower enum
On/Off
R/W
MO_Menu_Select
enum
worm, cook,
W
grill
MO_Timer
time
R
MO_TimerSet
time
W
Time
....
...
R/W
R
W
R
W
R
W
R
W
R
W
R
W
R
WM_WashingRemain
Time
gSet
WM_WashingRemain Time
g
WM_AutoWashing Bool
R/W
MO_Power
Type Description
enum {idle, washing,
Enum
rinsing, drying,
pumping}
Enum enum {very_soft, soft,
hard, very_hard}
enum {very_soft, soft,
Enum
hard, very_hard}
WM_Status
Table.1 Variable Objects of Air Conditioner
Name
Type
W
R
W
...
Table .3 Variable Object of Washing Machine
time
Time;
}MO_DB_Data;
........
........
........
Table .2 Variable Object of Micro Oven
typedef enum kindof_MO_ {
Warming,
Cook,
grill
} kindof_MO_Select;
typedef struct AS_info {
Visible_string
action_service_name;
AS_Statestate;
Resource_list
list_of_data_base_names;
Visible_string
start_argument;
}AS_info
The following syntax notations are the examples
of Data Base object and Action Service object.
They are composed of structure name and
element. In case of the DB object, the AS object,
all appliance have a similar syntax notation. As an
example, the described syntax notation of the
structure shows the DB object, AS object of the
Micro Oven. They are composed of the structure
name and elements.
114
device user in Step 4.
Implementations
Test-bed using XML based browsing technology
As a middleware, XML based home network
middleware is applied to our test-bed. UPnP
enables the browser to be extended to control
devices, and because UPnP devices are controlled
with explicit protocols, the browser must
somehow learn how to talk to UPnP devices. This
learning process is driven entirely from the device
itself and is accomplished entirely by uploading
an XML document that describes the capabilities
of the device.
a
) Step 1: Discovery and Identification
b) Step 2: Send and Request of Device
Description
Fig .3 Main Home Browser
Any device can transfer bulk data (e.g. files) or
control data streams from any device on the
network, to any device on the network, under the
control of any device on the network. Control
Point sends Discovery Request to a newly
plugged device and the device responds in Step 1.
When devices plugged into the network, the
device automatically must configure itself. The
device then announces its presence to other
devices already on the network using a simple
discovery protocol based on the Internet. HTTP
protocol and is immediately ready to share its
services with any device that requests them.
User Control Point requests UPnP description
document and the device sends it in Step 2. User
Control Points can retrieve a Description
Document by issuing an HTTP GET on a
Description URL. This URL is returned in the
location header of either an SSDP announcement.
An HTTP GET is used to retrieve sub-elements of
a Description Document that are expressed as
URLs. User Control Point requests additional
information, such as sends device user interface
in Step 4. device icons, the name and SCPD in
Step3. When user selects device icon, the
presentation server of the controlled device sends
115
c) Step 3:Additional Information(Icon, Name)
c) Step 4:Send Device User Interface
d) Step 5: Device Control
Fig. 4: XML based Browsing Scheme in Test-bed
Test-bed using JAVA technology
As a second solution, Java based technology is
applied for implementation of test-bed. The web
server is used for the monitoring and controlling
of the remote controlled device using Power Line
communication. As a PLC adaptor is connected to
PC by serial communication. The implemented
test-bed had flow as like Fig.5. The Messages are
transferred through Java applet in web browser.
In Fig.5.(a), CEbus devices are tested by ActiveX technology. In this case, the applied method is
similar to the prior test methodology except
discovery process.
a) Message Flow of Java based Test-bed
b) Block Diagram of Server-Client Model
Fig. 5: Java based PLC Test-bed
The example of simple codes for the home
gateway system is as follows. In first, the PLC
modem is initialized by the function with dialog
box. And then, the thread is produced for services
process. When it is connected from the client, the
message are transferred from the client. The
messages from the client are interpreted in
PLCPrintf( ) function, and then it sends proper
packets to the PLC modem(CEcom).
m_cebus.InitializeCECom();
listen(server_fd, 5);
…
while(1)
msg_size = recv(client_fd, buf, 2, 0);
buf[msg_size] = '';
if (flag == 1)
PLCPrintf(hDlg,buf);
flag = 0;
else flag = 1;
m_cebus.XMitPwrLine(cecom_data);
Test-bed using PDA
For the extending of application areas, the PDA
(personal device assistant) based on the home
automation is developed. In case of accessing the
home network, the user Interface program of the
Java applet is downloaded to the client, and then
user control the home appliance using the PDA.
Fig.6 represents the display panel of the PDA for
the home automation.
116
proposed. By using the developed message
specification, the home network test-bed based on
the PLC is implemented. The proposed message
specification is designed for the home appliances
as like white goods in home environment.
TCP/IP network by using the existing AC power
lines will be adopted in any residences. The
developed system will be used in Internet
applications that are delivered over high-speed
Internet connections such as DSL or cable.
In future, the HNMS will be extended to
continuously for the acceptance of reference
specification of the home network system. The
priority based event scheduling, the home
security and the energy management, the traffic
modeling of the home network using PLC will be
developed .
a) Example of Room Control
References
b) Example of Monitoring
Fig. 6:Home Automation Program using PDA
Fig.6.a) shows about the example of home
automation for the energy management. Fig.6.b)
represents about the example of the monitoring
S/W. Fig.7 represents the message flow between
the PDA and the home gateway which is
connected to the power line modem.
Fig .7: Message Flow between PDA and Home
Gateway
Conclusions
In this paper, the HNMS for whites goods is
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