WO2002071644A1

WO2002071644A1 - Plug-and-play power line communication device

Info

Publication number: WO2002071644A1
Application number: PCT/KR2002/000384
Authority: WO
Inventors: Chul Kim; Chung Ha Park
Original assignee: Planet System Co., Ltd.
Priority date: 2001-03-07
Filing date: 2002-03-06
Publication date: 2002-09-12
Also published as: KR100443949B1; KR20020071774A

Abstract

The present invention provides a power line communication device wherein a home code or a device address of each device can be set or changed automatically or easily by oneself by a user upon installation of the device and the set or changed contents can be informed to the other devices upon installing the device. The power line communication device can communicate with at least one external device through the power line, and performs processes of searching, changing and informing the address through the Hail communication performed by a program. The power line coupler couples a signal transmitting and receiving means with the power, and the signal transmitting and receiving means transmits and receives signals through the power line via the power line coupler. A controlling means controls the signal transmitting and receiving means. A storing means stores program codes for driving the controlling means. The program codes according to the present invention comprises a device code managing means for searching a device so as not to be overlapped with the device code of the external device. In addition, the program codes may further comprise a home code managing means for searching a home code of the external device, and setting it as an own home code.

Description

PLUG-AND-PLAY POWER LINE COMMUNICATION DEVICE

Technical Field The present invention relates to a communication device, and more particularly, to a plug-and-play power line communication (PLC) device capable of easily performing configuration of an address when the device is connected, to a node of a power line communication system.

Background Art

A domain name called as a home code and a device address are assigned to each communication device that is connected with a power line communication system as a node that transmits and receives data through a power line.

Here, a domain means a virtual region controlled by a single user on the power line, and the domain name means a name uniquely assigned thereto in order to identify the domain. Further, the device address includes a unique name of each communication device, and designates a path of transmitting the data to a relevant communication device.

In the prior art, the home code and the device address were set through procedures that were individually performed in respective communication devices that would be connected as the nodes, and this often caused various complicated problems.

The home code and the device address must be newly set even when the assigned domain is changed, or a new communication device is connected as a newly added node of the previously set domain in addition to when a new domain is set. However, this setting method is a considerably difficult operation for the general users.

Disclosure of Invention

Therefore, an object of the present invention is to provide a power line communication device wherein a home code or a device address of each device can be set or changed automatically or easily by oneself by a user upon installation of the device, and which can prohibit overlapped use of the domain name or the device address by informing other communication devices connected to a power line communication system of the set and changed contents.

The power line communication device according to the present invention can communicate with at least one external device through the power line, and performs processes of searching, changing and informing the address through the Hail communication performed by a program.

The power line communication device according to the present invention comprises a signal transmitting and receiving means, a power line coupler, a controlling means and a storing means. The power line coupler couples the signal transmitting and receiving means with the power line, and the signal transmitting and receiving means transmits and receives signals through the power line via the power line coupler. The controlling means controls the signal transmitting and receiving means. The storing means stores program codes for driving the controlling means.

The program codes according to the present invention comprises a device code managing means for searchmg a device code of the at least one external device and then setting a device code of the power line communication device so as not to be overlapped with the device code of the external device. In addition, the program codes may further comprise a home code managing means for searching a home code of the external device, searching a home code which is not overlapped with the home code of the external device, and setting it as an own home code. According to an aspect of the present invention, there is provided a plug-and-play power line communication device that comprises a power line coupler for connecting with a power line as a node constituting a power line communication system, a transceiver for broadcasting a signal on the power line or receiving the signal through the power line, and a microcontroller for controlling an operation of the transceiver. The microcontroller may be constructed to search on a domain name different from other domain names by performing a Hail communication upon its initial connection with the power line and to automatically set or determine a unique address in which the searched domain name is placed on a higher level and its own name is placed on a lower level.

The microcontroller may be constructed to broadcast a Hail Request signal including a domain name candidate through the transceiver on the power line upon initial connection with the power line and to determine the address by adopting the domain name candidate as a domain name if a Hail NAK signal is not received within a predetermined period of time.

The microcontroller may be constructed to broadcast a Hail Request signal including a domain name candidate through the transceiver on the power line when user's instructions are inputted through a remote controller or an operation button and to determine the address by adopting the domain name candidate as a domain name if a Hail NAK signal is not received within a predetermined period of time.

According to another aspect of the present invention, there is provided a method in which a power line communication device connected as a node to a power line through a power line coupler determines a virtual region identified by a unique name as a domain in a power line communication system and determines an address including the relevant domain name. This method comprises the steps of broadcasting a Hail Request signal including a domain name candidate on the power line when the device is initially connected to the power line, waiting for receiving a Hail NAK signal which the other nodes broadcast on the power line with respect to the Hail Request signal just after the broadcasting step, and determining the address by adopting the domain name candidate as the domain name if a Hail NAK signal is not received within a predetermined period of time at the waiting step.

It is preferable that the method further comprises the steps of returning to the broadcasting step to broadcast a Hail Request signal including a new domain name candidate if the Hail NAK signal is received at the waiting step, and continuously performing the waiting step and the address determining step.

According to a further aspect of the present invention, there is provided a power line communication network comprising at least one domain constituted by a virtual region including at least one node connected to a power line, at least one power line communication device having a power line coupler for connecting with the power line as the node, a transceiver included in each power line communication device for broadcasting a signal on the power line or receiving the signal through the power line, and a microcontroller included in each power line communication device for controlling an operation of the transceiver. In this power line communication network, the microcontroller of the at least one power line communication device automatically determines an address including a unique domain name by searching on a domain name different from other domain names tluough the Hail communication when the device is initially connected to the power line.

Brief Description of Drawings FIG. 1 is a diagram showing one example of a power line communication system according to the present invention.

FIG. 2 is a diagram showing one example of an address assigned to each device. FIG. 3 is a diagram showing one example of a program for assignment and change of the address according to the present invention. FIG. 4 is a flowchart showing a home code searching procedure performed by a home code searching sub module shown in FIG. 3.

FIG. 5 is a flowchart showing a home code setting procedure performed by a home code setting sub module shown in FIG. 3.

FIG. 6 is a flowchart showing a home code deleting procedure performed by a home code deleting sub module shown in FIG. 3.

FIG. 7 is a flowchart showing an address searching procedure performed by a device code searching sub module shown in FIG. 3.

FIG. 8 is a flowchart showing an address changing/setting procedure performed by an address changing/setting sub module shown in FIG. 3. FIGS. 9 and 10 are flowcharts showing an address change completion informing procedure performed by an address change completion informing sub module shown in FIG. 3.

FIG. 11 is a flowchart showing a region code setting procedure performed by a region code setting module shown in FIG. 3.

FIG. 12 is a flowchart showing a power-on reset procedure performed by a power-on reset module shown in FIG. 3.

FIG. 13 is a flowchart showing a mapping procedure performed by a mapping module shown in FIG. 3.

Best Mode for Carrying Out the Invention Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows a portion of a power line communication system according to the present invention, for example two devices connected to a power line. A signal can be received and transmitted through the power line 100 by a first device 110 and a second device 130, and various other devices may be included as a portion of the power line communication system connected to the power line 100. In the respective devices 110 and 130, power line couplers 112 and 132 allow transmitting units 114 and 134 and receiving units 116 and 136 to receive and transmit the signal through the power line 100, respectively, by coupling the transmitting units 114 and 134 and the receiving units 116 and 136 to the power line 100. The transmitting units 114 and 134 broadcast the signal modulated from data out of a microcontroller 118 or a circuit (not shown) for performing original functions of the electrical devices 110 and 130. The receiving units 116 and 136 detect the signal on the power line 100, demodulate the signal, and transfer the demodulated signal to the microcontroller 118 or the electrical devices. Herein, the phrase "the signal on the power line" means not the signal transmitted through the power line from one node to a specific node but the signal broadcasted on the power line communication network without being routed to the specific node from one node. The microcontrollers 118 and 138 control the operations of the transmitting units 114 and 134 and the receiving units 116 and 136. Memories 120 and 140 store a program for controlling the operations of the microcontrollers 118 and 138, device addresses, operation data and data temporarily generated in processes of the operations.

The respective devices 110 and 130 have addresses uniquely assigned to the respective devices on a power line communication network. FIG. 2 shows an example of the configuration of the addresses assigned to the respective devices. As shown in FIG. 2, a device address may include a home code 150, a region code 152, a group code 154 and a device code 156. According to the present embodiment, the home code 150 is assigned to respective domain such as an individual home, an office or an organization. In a case where one domain is divided to be managed, the region code 152 can be assigned to each divided region. The group code 154 can be assigned to a group in a case where devices belonging to one domain are divided into several groups and each group is individually controlled. The device code 156 is a code assigned to each device. In the power line communication system according to this embodiment, although the home code 150 and the device code 156 are essentially assigned thereto, the region code 152 and the group code 154 are assigned thereto only if necessary. Meanwhile, even though nodes belong to a domain identified with an identical home code 150, if the region codes 152 or the group codes 154 are assigned thereto and the region codes 152 or the group codes 154 are different from one another, a unique address can be configured in a case where the identical device code 146 is assigned thereto.

Hereinafter, the operation and configuration of the power line communication system according to the preferred embodiment of the present invention will be described in connection with a household power line communication system implemented on the power line communication network in which electric home appliances are arranged in a residential space such as a home. In the household power line communication system, the home appliances are mainly connected as the nodes.

According to the present embodiment, a program for address assignment and change is installed in the memory 120. This program is loaded into and executed in the microcontroller 118 so as to allow the device address to be assigned or changed in a plug-and-play manner. Herein, "a plug-and-play manner" means that it is easy for a user to use a device, which will be included as a node of the power line communication system network, by automatically configuring the address when the user simply plugs an electricity supplying plug of the device, as if this term is utilized in a computer area as a terminology indicating easiness of the use in such a degree that an auxiliary board or a peripheral device can be operated well when it is simply inserted into a main body of the computer.

FIG. 3 shows the configuration of the program, which is used in the power line communication system according to the embodiment of the present invention, as a block diagram of the function modules. As shown in FIG. 3, the program comprises a home code managing module 160, a device code managing module 170, a region code setting module 180, a power-on reset module 185 and a mapping module 190. In this embodiment, the home code managing module 160 comprises a plurality of sub modules, i.e. a home code searching sub module 162, a home code setting sub module 164 and a home code deleting sub module 166. In addition, the device code managing module 170 also comprises a plurality of sub modules, i.e. a device code searching sub module 172, a device code changing/setting sub module 174 and a device code change completion informing sub module 176. Functions of these sub modules will be described later.

Each code of the address is set as "FFFF" at an initial condition where the devices are firstly installed and electric power is supplied thereto. At this state, each device sets the address thereof by performing an address setting function by means of the plug-and-play manner according to the present invention. At this time, all devices of which the electricity supplying plugs are connected to a plug receptacle of the power line of all neighboring homes or homes located at close range are communicable with one another by connection through the power line. However, the devices belonging to each home have a unity property as nodes included in one virtual domain which is identified by one home code 150 on the power line communication network.

One of important characteristics of the device for use in the power line communication system according to the present invention is that the address searching, changing, and informing procedures can be performed through the Hail communication. Herein, the Hail communication means a communication method in which a device broadcasts data or a request signal on the power line communication network so that any devices can receive it, and the receiving devices broadcast response signals, which are respectively determined in relation with the data or the request signal, on the power line communication network.

The power line communication system according to the present embodiment standardizes three signals, i.e. Hail Request, Hail Acknowledge (ACK) and Hail No Acknowledge (NAK), in order to easily identify the request signal and the response signals, and then performs the Hail communication.

The Hail Request is a signal included in a data packet which a device broadcasts as the data or the request signal on the power line communication network so that any other devices can receive the data or the signal, and is a signal for requesting the all devices, which receive the relevant data packet, to respond the received data packet with "yes", or "no".

The Hail NAK is a signal by which the device that has received the data packet including the Hail Request rejects the request of the broadcasting device, which is included in the relevant data packet. Preferably, the power line communication system according to this embodiment is configured such that if the device that has received the data packet including the Hail Request intends to reject the request of the broadcasting device included in the relevant data packet, it broadcasts the Hail NAK continuously and repeatedly as soon as it receives the corresponding data packet.

The Hail ACK is a signal by which the device that has received the data packet including the Hail Request acknowledges the request of the broadcasting device, which is included in the relevant data packet. In this embodiment, no response is regarded as the Hail ACK signal. The device that has broadcasted the data packet including the Hail Request is configured such that the device that has not broadcasted the Hail NAK for the relevant Hail Request until a predetermined period of time lapses is considered as acknowledging the request of the broadcasting device, which is included in the relevant data packet.

In an initial mode of the device before the electric power is firstly supplied thereto, the entire address including the home code is set as "FFFF", so that the device is maintained in a standby state where it does not have a specific address. When the power is firstly supplied, the home code can be searched, set and deleted as described below. FIG. 4 shows the home code searching procedure performed by the home code searching sub module 162. A home code searching state is a procedure for assignment of a home code to be uniquely used by the user when the power line communication device is firstly connected to the power line. An unused home code is detected by searching other homes or all regions where communication can be made. If a master device exists among various devices, the home code searching state is applied only to the master device. Preferably, only a specific device is configured to operate as the master device for performing the home code searching procedure. In the master device, as soon as an electricity-supplying plug thereof is plugged into the power plug receptacle, the home code searching sub module 162 is driven and the transmitting unit simultaneously broadcasts a Hail Request signal on the power line communication network. However, the present invention is not limited to such a method, and the user can push down a button of a remote controller or the device for the general appliance and thus intentionally drive the home code searching sub module 162 and the transmitting unit so as to allow the device to perform as the master device. In the latter case, the button of the device or an operation controlling unit of the device, and the program according to the present invention are linked through an Application Program Interface (API) serving as middleware. This is equally applied to the following.

Firstly, if the power is supplied to the power line communication device, the transmitting unit enters into the standby state (SOI). When the master device starts to search the home code

(S02), the transmitting unit broadcast an arbitrary home code (for example, sequentially selected from the first home code) to be intended to use, together with the home code Hail Request signal

(S03).

Each of all receiving devices that have received the home code Hail request signal determines whether or not the received home code is equal to its own home code. If the received home code is equal to its own home code, each receiving device immediately broadcasts the Hail NAK signal (S04). On the other hand, if the received home code is not equal to its own home code, each receiving device maintains a no-response state of broadcasting no signals instead of transmission of the Hail ACK signal (S06).

When the Hail NAK signal is received, the transmitting unit deletes the previously broadcasted home code and broadcasts the home code Hail Request signal, together with new home code data again (S05). These procedures are repeated until the Hail NAK signal is not received from any receiving devices or until a predetermined searching period of time lapses.

If any one of the receiving devices that have received the home code Hail Request signal does not broadcast the Hail NAK signal and is kept in the no-response state, the transmitting unit regards the no-response state as the Hail ACK, completes the home code searching procedure and informs the microcontroller of the last broadcasted home code so that the last broadcasted home code is assigned as its own home code (S07).

FIG. 5 shows the home code setting procedure performed by the home code setting sub module 164 shown in FIG. 3. When the home code setting procedure at the master device is completed, the user or a program installed in the master device can instruct that the home code assigned to the master device is set to all other devices (Sl l). If the transmitting unit broadcasts home code information on the power line communication network (SI 2), the receiving devices that have not yet had a home code assign the received home code as their own home code (SI 3). As a result, if there are one or more devices to which the home code is assigned, all devices to which the home code has not yet been assigned are informed of the home code information at once through the broadcasting transmission. Thus, the home code can be assigned thereto with only one operation even though the other devices are additionally and continuously connected thereto. It is preferable that these home code setting procedures be led only by the device set as the master device.

If a device is not firstly connected to the power line but brought thereto and installed thereat after it was previously connected to the power line at a place, an address including a home code of the relevant device has been stored therein as not "FFFF" but that previously assigned thereto at the prior place. Further, it may be necessary to change the home codes of all the devices belonging to a domain in which the addresses have been already configured due to the other reasons. FIG. 3 shows a procedure of deleting the home code, which has been previously set in the above case, by the home code deleting module 66. FIG. 6 shows the home code deleting procedure performed by the home code deleting sub module 166 shown in FIG. 3. If the master device instructs the deletion of the home code (S21), the instructed device changes its own home code into an initial value ("FFFF") and then informs it (S22, S23).

The device of which the home code has been set can automatically configure the address using the Hail communication method. Otherwise, the user may set an arbitrary address or change it. The device may set an address group in accordance with the type of the device, and it is possible to overlappingly use the address. The address setting can be performed by the two methods shown in FIGS. 7 and 8.

As described above, an initial address of the device has a "FFFF" value, and this is a state where there is no address. The device to which no address is set automatically transmits a plug-and-play address Hail Request signal when initiating the specific operation (function) after supply of the power source, so that its own address is obtained and set. The address setting by the plug-and-play manner does not allow the overlapped use of the address. FIG. 7 shows the address searching procedure performed by the device code searching sub module 172 shown in FIG. 3. First, if the power is supplied to the device, the transmitting unit enters the standby state (S31). When the master device instructs the device to perform the initialization operation (S32), the device broadcasts any desired address together with the address Hail Request signal (S33). Each of the receiving devices instantly broadcasts the Hail NAK signal if the received address data is equal to its own address (S34). On the other hand, if the received address data is not equal to the own address, each of the receiving device maintains the no-response state so that the use of requested address data is allowed instead of transmission of the Hail ACK signal (S36). If the Hail NAK signal is received, the transmitting unit again broadcasts the address Hail Request signal together with a new address data (S35). These procedures are repeated until the Hail NAK signals are not received from any received devices or until the predetermined searching period of time lapses. If any one of the devices that have received the address Hail Request signal does not broadcast the Hail NAK signal, the transmitting unit regards the above as the Hail ACK signal and completes the address searching procedure. Further, the device informs the microcontroller of the master device of the last broadcasted home code so that the last broadcasted home code is set as its own address (S37). In cases where a device resets the currently used address, an overlapped address is set for synchronous control of the same types of device groups, or an address is changed for cancellation of the synchronous control of the device groups, the address used in the corresponding device should be changed. FIG. 8 shows the address changing/setting procedure performed by the device code changing/setting sub module 174 shown in FIG. 3. If the master device instructs the device to change the address (S41, S51), the instructed device broadcasts any desired address together with an address Hail Request signal (S42, S45, S52). At this time, in order to prevent the overlapping of the addresses between different device groups, the device broadcasts the signal including its own group code when transmitting the Hail Request signal. If the received address data is equal to its own address, the device compares the group code included in the Hail Request signal with its own group code. If the two group codes are different from each other, the receiving device immediately broadcasts the Hail NAK signal and rejects the use of the relevant address (S44). However, if the two group codes are equal to each other, the received device maintains the no-response state so that the use of the requested address is allowed instead of the transmission of the Hail ACK signal (S47). Furthermore, even when the received address data is different from its own address, each of the receiving devices also maintains no-response state so that the use of the requested address data is allowed instead of the transmission of the Hail ACK signal (S53). If any one of the devices that have received the address Hail Request signal does not broadcast the Hail NAK signal, the transmitting unit regards the above as. the Hail ACK signal and completes the address searching procedure. Further, the device informs the master device of the last broadcasted home code so that the last broadcasted home code is assigned to its own address (S48, S54).

When the address of the plug-and-play device is changed, the device may inform other devices used for monitoring or mapping the conditions of the devices of the information on its own changed address (active address) and the deleted address (inactive address). FIG. 9 shows the address change completion informing procedure performed by the device code change completion informing sub module 176 shown in FIG. 3.

First, the master device instructs the device, in which the address change is completed, to inform the address change completion (S61). Accordingly, the device broadcasts an inactive address-informing signal in which the unchanged address is used as its data (S62). If the inactive address-informing signal is received (S63), the devices having the monitoring or mapping function delete the relevant inactive address or performs the related process (S64).

Subsequently, the transmitting unit, of which address has been changed broadcasts the active address-informing signal in which the changed address is used as its data (S65). If the active address-informing signal is received (S66), the devices having the monitoring or mapping function add the relevant active address or perform the related process

(S67).

The condition where any addresses are overlapped among a number of devices may occur. Herein, if the group codes or the region codes are different from each other, there is no problem. If all the codes are the same as each other, however, the address of at least a device must be changed. If the address of any one of two or more devices having the overlapped address is changed, it is preferable that the address of the other device which has been made inactive by the address change completion report be allowed to be activated again, in order to prevent the address of the device, of which address was overlapped but must be still maintained from being inactive by the device of which address was changed. Accordingly, in the present invention, the address of the device, which had the same address as the changed device, is made activated again and restored.

In FIG. 10, it is assumed that the addresses of the first and second transmitting units are the same as each other. If the address of the first transmitting unit is changed, the first transmitting unit broadcasts the inactive address and the active address so that the devices having the monitoring or mapping functions can perform the related process for the relevant inactive address and the active address, as described above (S71 to S74).

If the second transmitting unit receives a signal informing that its own address is inactivated (S75), the second transmitting unit broadcasts the active address-informing signal, in which its own address is used as a broadcasting data, in order to activate its own address again.

Therefore, the devices having the monitoring or mapping functions can perform the related process for the relevant active address (S76 to S78).

The region code setting module 180 shown in FIG. 3 assigns a location code for the installation region to each of the devices so as to allow the selective control in accordance with the location and to allow the confirmation of the location of each device at the monitoring device.

Referring to FIG. 11, the region code setting procedure will be explained. When the user assigns the region code to the device (S81), the relevant device broadcasts the assigned region code to other devices and informs the user that the broadcast was completed (S82, S83). In FIG.

11, the receiving device may be a device serving as a main device such as an internet gateway, a home server and the like. In such a case, the user can view an overall layout of the device in an image format through the internet. To this end, nicknames for the respective devices may be set in the on-line or off-line state.

For each of the devices to which the home code and address are assigned, the power-on reset module 185 shown in FIG. 3 broadcasts information on the device when the power is turned off and is then supplied thereto again and informs other devices that the corresponding devices are made active. Referring to FIG. 12, just after the user supplies the power to the device (S85), if the home code and the address are assigned to the relevant device, the corresponding device broadcasts the other devices that the device itself was activated (S86).

Each device has its own information on the address, the group code, the region code and the relevant state. Further, the monitoring or mapping devices register the information obtained from each device into a mapping table and uses the registered information when necessary.

Referring to FIG. 13, a mapping procedure performed by the mapping module 190 will be described. For example, if information collection is instructed by the mapping module 190 of the mapping device or the user (S91), the mapping device (transmitting unit) broadcasts the information request signal to the devices (S92). If each receiving device receives the information request signal (S93), it broadcasts its own information data to the transmitting unit while going into standby in accordance with the priority order or the collision-prevention algorithm (CSMA/CD) (S94 to S97). The transmitted data is stored in the mapping table (S98).

It will be readily understood by the skilled persons in the art that the present invention can be practiced in other specific forms without changing its technical spirit or its essential features. Therefore, it should be understood that the aforementioned embodiments are not restrictive but illustrative in every respect. The scope of the present invention is defined by the appended claims rather than the detailed description of the invention. The spirit and scope of the claims, and all changes and modifications derived from the equivalent concept should be constructed as falling within the scope of the present invention.

Industrial Applicability

As described above, according to the present invention, the home code or the device address can be set and changed automatically or easily by oneself by the user upon installation of the power line communication device, and the set/changed contents are transferred to other devices. Therefore, there are advantages in that it is convenient to use the device, the hacking from the outside can be prevented, and the plug-and-play can easily be implemented in the small-sized devices such as electric home appliances even where a small capacity software program is required.

Claims

1. A plug-and-play power line communication device, comprising: a power line coupler for connecting with a power line as a node constituting a power line communication system; a transceiver for broadcasting a signal on the power line or receiving the signal through the power line; and a microcontroller for controlling an operation of the transceiver, wherein the microcontroller is constructed to search on a domain name different from other domain names by performing a Hail communication upon its initial connection with the power line and to automatically set or determine a unique address in which the searched domain name is placed on a higher level and its own name is placed on a lower level.

2. The device as claimed in claim 1, wherein the microcontroller is constructed to broadcast a Hail Request signal including a domain name candidate through the transceiver on the power line upon initial connection with the power line and to determine the address by adopting the domain name candidate as a domain name if a Hail NAK signal is not received within a predetermined period of time.

3. The device as claimed in claim 1, wherein the microcontroller is constructed to broadcast a Hail Request signal including a domain name candidate through the transceiver on the power line when user's instructions are inputted through a remote controller or an operation button and to determine the address by adopting the domain name candidate as a domain name if a Hail NAK signal is not received within a predetermined period of time.

4. The device as claimed in any one of claims 1 to 3, wherein the microcontroller is constructed to broadcast a Hail Request signal including a new domain name candidate through the transceiver on the power line when user's instructions are inputted through a remote controller or an operation button after the domain name has previously been determined and to determine the address by changing the previously determined domain name into the domain name candidate if a Hail NAK signal is not received within a predetermined period of time.

5. The device as claimed in claim 4, wherein the microcontroller is constructed to broadcast the Hail NAK signal on the power line if the domain name which is included in the Hail Request signal received through the transceiver, is equal to its own domain name and to maintain no-response state if the received domain name is different from its own domain name.

6. The device as claimed in claim 4, wherein the microcontroller is constructed to determine the address by setting between the domain name and its own domain name, a region code for identifying one or more regions into which a virtual region for forming a domain is divided.

7. The device as claimed in claim 4, wherein the microcontroller is constructed to determine the address by setting, between the domain name and its own domain name, a group code for identifying one or more groups into which a plurality of the power line communication devices comiected as nodes belonging to a domain are classified according to the types.

8. A method in which a power line communication device connected as a node to a power line through a power line coupler determines a virtual region identified by a unique name as a domain in a power line communication system and determines an address including the relevant domain name, comprising the steps of: broadcasting a Hail Request signal including a domain name candidate on the power line when the device is initially connected to the power line; waiting for receiving a Hail NAK signal which the other nodes broadcast on the power line with respect to the Hail Request signal just after the broadcasting step; and determining the address by adopting the domain name candidate as the domain name if a Hail NAK signal is not received within a predetermined period of time at the waiting step.

9. The method as claimed in claim 8, further comprising the steps of returning to the broadcasting step to broadcast a Hail Request signal including a new domain name candidate if the Hail NAK signal is received at the waiting step, and continuously performing the waiting step and the address deteπnining step.

10. The method as claimed in claim 8, wherein the broadcasting step is performed by a microcontroller when user's instructions are inputted through a remote controller or an operation button.

11. The method as claimed in any one of claims 8 to 10, further comprising the steps of: broadcasting a Hail Request signal including a new domain name candidate on the power line through a transceiver when user's instructions are inputted through a remote controller or an operation button after the domain name has previously been determined; waiting for receiving a Hail NAK signal which the other nodes broadcast on the power line with respect to Hail Request signal just after the broadcasting step; and determining the address by changing the previous domain name into the new domain name candidate if a Hail NAK signal is not received within a predetermined period of time at the waiting step.

12. The method as claimed in claim 8, further comprising the step of broadcasting the Hail NAK signal on the power line when a domain name included in the Hail Request signal which the other nodes broadcast on the power line after the address determining step is equal to its own domain name.

13. The method as claimed in claim 8, further comprising the steps of: determining the address by dividing the nodes having the same domain name after the address determining step according to the virtual regions; and assigning region codes to the divided nodes.

14. The method as claimed in claim 8, further comprising the steps of: determining the address including a group code by classifying the nodes having the same domain name after the address determining step according to the types; and assigning group codes to the classified nodes.

15. The method as claimed in claim 8, wherein in the address determining step, the address is determined by placing the domain name candidate determined as the domain name on a higher level and placing the group code identically assigned to the similar nodes on a lower level.

16. The method as claimed in claim 15, when a first node broadcasts an address changing instruction on the power line, further comprising the steps of: broadcasting a Hail Request signal including a new address candidate on the power line, which is conducted by a second node; receiving the Hail Request signal and comparing the requested address with one's own address, which is conducted by a third node; comparing a group code included in the Hail Request signal with one's own address, which is conducted by the third node ascertained to have the same address with the requested address; broadcasting a Hail NAK signal in relation to the Hail Request signal on the power, which is conducted by the third node ascertained to have a group code different from the group code included in the Hail Request signal; and informing the first node that a home code included in the Hail Request signal is used as a portion of one's own address, which is conducted by the second node that not receive any Hail NAK signal within a predetermined period.

17. The method as claimed in claim 15, when a first node broadcasts an address changing completion informing instruction on the power line, further comprising the steps of: receiving the address changing completion informing instruction and broadcasting an inactive address informing signal including an address before changed, which is conducted by a second node; receiving the inactive address informing signal and deleting the inactive address from an active address list, which is conducted by a third node; broadcasting an active address informing signal including an address after changed, which is conducted by the second node; and receiving the active address informing signal and adding the active address to the active address list, which is conducted by the third node.

18. A power line communication network comprising: at least one domain constituted by a virtual region including at least one node connected to a power line; at least one power line communication device having a power line coupler for connecting with the power line as the node; a transceiver included in each power line communication device for broadcasting a signal on the power line or receiving the signal through the power line; and a microcontroller included in each power line communication device for controlling an operation of the transceiver, wherein the microcontroller of the at least one power line communication device automatically determines an address including a unique domain name by searching on a domain name different from other domain names through the Hail communication when the device is initially connected to the power line.

19. The power line communication network as claimed in claim 18, wherein the microcontroller is constmcted to broadcast a Hail Request signal including a domain name candidate through the transceiver on the power line upon initial connection with the power line and to determine the address by adopting the domain name candidate as a domain name if a Hail NAK signal is not received within a predetermined period of time.

20. The power line communication network as claimed in claim 18, wherein the microcontroller is constructed to broadcast a Hail Request signal including a domain name candidate through the transceiver on the power line when user's instructions are inputted through a remote controller or an operation button and to determine the address by adopting the domain name candidate as a domain name if a Hail NAK signal is not received within a predetermined period of time.

21. The power line communication network as claimed in claim 18, wherein the microcontroller is constructed to broadcast a Hail Request signal including a new domain name candidate through the transceiver on the power line when user's instructions are inputted through a remote controller or an operation button after the domain name has previously been determined and to determine the address by changing the previously determined domain name into the domain name candidate if a Hail NAK signal is not received within a predetermined period of time.

22. The power line communication network as claimed in claim 18, wherein the microcontroller is constructed to broadcast the Hail NAK signal on the power line if the domain name which is included in the Hail Request signal received through the transceiver, is equal to its own domain name and to maintain no-response state if the received domain name is different from its own domain name.

23. The power line communication network as claimed in claim 18, wherein the microcontroller is constructed to determine the address by setting a region code for identifying one or more regions into which a virtual region for forming a domain is divided.

24. The power line communication network as claimed in claim 18, wherein the microcontroller is constructed to determine the address by setting a group code for identifying one or more groups into which a plurality of the power line communication devices connected as nodes belonging to a domain are classified according to the types.