KR20120059205A - Method for providing mobility of device in wireless sensor network based on 6LoWPAN - Google Patents

Abstract

The present invention relates to a method for supporting device mobility in an Internet Protocol Version 6 (IPv6) based wireless sensor network, and more specifically to a 6LoWPAN (IPv6 Low-power Wireless Personal Area Network) based wireless sensor network. The present invention relates to a method for supporting mobility of a device moved to a mobile network by separating an identifier (ID) and a location of a device.
The method for supporting mobility of a device according to the present invention separates and manages an identifier and location information of a device in a 6LoWPAN-based sensor network, thereby supporting device mobility by changing only location information without changing an identifier even when the device moves. In addition, the method for supporting mobility of a device according to the present invention efficiently manages mobility of a sensor device having a low energy source and a limited process by managing the mobility of a mobile device by a gateway that manages NEMO on behalf of the device when the device moves to NEMO. can do.

Description

Method for providing mobility of device in wireless sensor network based on 6LoWPAN

The present invention relates to a method for supporting device mobility in an Internet Protocol Version 6 (IPv6) based wireless sensor network, and more specifically to a 6LoWPAN (IPv6 Low-power Wireless Personal Area Network) based wireless sensor network. The present invention relates to a method for supporting mobility of a device moved to a mobile network by separating an identifier (ID) and a location of a device.

Sensor networks are one of the most important technologies that will become the foundation environment in the ubiquitous society. In order to manage such a sensor network more efficiently, interworking with an IP network is emerging as an essential condition. In line with this trend, 6LoWPAN was created in the IETF Working Group to use TCP / IP over IEEE 802.15.4. That is, 6LoWPAN (IPv6 over Low power WPAN) refers to a technology for mounting Internet Protocol Version 6 (IPv6) on a low power Wireless Personal Area Network (WPAN) using IEEE 802.15.4 as PHY / MAC. In general, 6LoWPAN includes devices that work together to physically connect to a real-world application environment. A representative example of the devices may be referred to as a mobile sensor node or a mobile network (NEMO).

Here, NEMO supports mobility of a network unit through a mobile router (MR) when a network moves, and provides continuous internet connection to various mobile terminals and fixed terminals existing in the subnet inside the MR. The MR of the NEMO consists of at least two network interfaces divided into egress and ingress interfaces. The external interface supports network mobility by connecting to an external network or another NEMO, and the internal interface constitutes a subnet inside the MR.

The 6LoWPAN-based sensor node or NEMO described above is an IP architecture-based technology that follows the TCP / IP layer model. TCP / IP is a network transport protocol that can be used to transfer data between computers running different operating systems. TCP is a protocol for dividing and packing transmission data into a certain unit, and IP is a protocol for transmitting and receiving data directly. All computers on the Internet follow the protocol established by the Internet Standards Committee. The Internet standard protocol is TCP / IP. The hierarchical structure of the TCP / IP layer model includes a first layer as a physical layer (L1), a second layer as a data link layer (L2), and a third layer as a network layer (L3). The fourth layer is composed of a transport layer (L4).

Referring to the TCP / IP layer model with reference to FIG. 1, the network layer establishes a logical link for transmitting data from a transmitting sensor node to a receiving terminal, and divides upper layer data into small packets to transmit data in units of networks. Play a role. Meanwhile, the transport layer detects an error in data transmitted and received at the network layer and performs a role of transmitting and receiving data without error between the transmitting sensor node and the receiving terminal, that is, between the end and the end. In addition, the application layer provides a means of accessing the network to exchange data between the transmitting sensor node and the receiving terminal. Here, the network layer uses the IP address as the location information to locate the receiving sensor node and transmit the packet to the receiving terminal, and the transport layer and the application layer are used to distinguish the communication session or the sensor node. Use an IP address as an identifier. In other words, the current Internet communication architecture uses IP addresses as sensor node identifiers and location information in common.

The sensor node's IP address should not be changed while the sensor node is connecting to the communication session.If the sensor node is moved in the current Internet communication architecture, the sensor node's location information is moved every time, even if the sensor node's identifier is not changed. Is changed. Therefore, as the sensor node moves, the IP address, which is the location information of the sensor node, is changed so that the communication session cannot be maintained and the communication is stopped.

The future Internet environment demands mobility and multi-homing, but the current Internet communication architecture is not suitable due to the common use of IP addresses as device identifiers and location information.

The present invention is to solve the problems of the above-described IP architecture based on the TCP / IP layer model, and to achieve the present invention is to support the mobility of the device by separating and managing the device identifier and location information in the 6LoWPAN-based sensor network To provide a way.

Another object of the present invention is to provide a method for supporting device mobility when a device moves to NEMO by separately managing device identifiers and location information in a 6LoWPAN based sensor network.

Another object of the present invention is to provide a method for supporting mobility of a device through a lightweight mobility support architecture and minimized signaling in a personal area network (PAN) when the device moves to a mobile network.

In order to achieve the object of the present invention, a method for supporting mobility of a device according to the present invention is a gateway for managing a mobile network when an external device moves to a mobile network located in a personal area network (PAN) of a home mapping server. Receiving a location update request message from an external device; determining whether the external device is an external device registered in the external mapping server based on the external device identifier; and when the external device is an external device registered in the external mapping server, the external device identifier. To request the location information of the external mapping server in which the external device is registered by sending a message to the device management server, and the external device location information having the gateway location information and the external device identifier and mapped to the external device identifier. Sending a location change request message requesting a change to a location to an external mapping server, receiving a location change response message of an external device from an external mapping server in response to the location change request message, and sending a location update response message to a gateway It includes.

Here, when the external device moves to the mobile network, the external device sends a registration request message to the mobile router for registering the mobile device's movement information to the home mapping server or the external mapping server, and the mobile router sends the registration request message back to the mobile network. When the gateway managing the mobile network receives the location update response message, the gateway sends a registration response message to the mobile router indicating that the registration of the mobile information of the external device is completed, and the mobile router sends a registration response message again. Is transmitted to an external device.

Meanwhile, the method of supporting mobility of a device according to the present invention includes changing location information of an external device mapped to an external device identifier to a gateway location of a personal area network of a home mapping server when the external device is registered in the home mapping server. And transmitting a location update response message to the gateway of the personal area network of the home mapping server.

The mobility support method of the device according to the present invention has the following various effects compared to the prior art.

First, the method for supporting mobility of a device according to the present invention separates and manages an identifier and location information of a device in a 6LoWPAN-based sensor network, thereby supporting device mobility by changing only location information without changing an identifier even when the device moves.

Second, the mobility support method of the device according to the present invention efficiently manages mobility of a sensor device having a low energy source and a limited process by the gateway managing the NEMO on behalf of the device when the device moves to NEMO. Can manage

1 illustrates a TCP / IP layer model.
2 is a diagram schematically illustrating a concept of separately managing an identifier and location information of a device.
FIG. 3 illustrates a system according to an embodiment of the present invention, which supports mobility of a device based on the concept described in FIG. 2.
4 is a system diagram for explaining an example of a device mobility support method according to the present invention.
FIG. 5 is a diagram illustrating a message transmitted and received when a device registered in an external mapping server moves to a mobile network of a personal area network managed by a home mapping server in the device mobility support method according to the present invention.
6 is a view illustrating an example of a registration request message and a registration response message according to the present invention.
FIG. 7 illustrates an example of a dispatch header pattern and a compressed header pattern of a 6LoWPAN IP header according to the present invention in more detail.
8 is a view for explaining an example of a mobile header dispatch and a data field of a 6LoWPAN IP header according to the present invention in more detail.
9 illustrates an example of a name of a device registered in the device management server, a device identifier, and location information of the registration mapping server.
10 is an example of location information registered in an external mapping server before / after sensor node 1 moves to a new personal area network (PAN2).
FIG. 11 is an example of location information registered in a home mapping server before / after sensor node 1 moves to a new personal area network (PAN2).

Hereinafter, a method of supporting mobility of a device according to the present invention will be described in detail with reference to the accompanying drawings.

2 is a diagram schematically illustrating a concept of separately managing an identifier and location information of a device.

Referring to FIG. 2, in the proposed layer model, an identification layer is separately disposed between a transport layer and a network layer to map an identifier and location information of a device through the identification layer, thereby distinguishing the identifier and location information of the device. Hierarchical model to use. That is, when the device moves, only the location information of the device is changed without changing the identifier of the device. The location information of the changed device is mapped to the device identifier in the identification layer.

FIG. 3 illustrates a system according to an embodiment of the present invention, which supports mobility of a device based on the concept described in FIG. 2.

Referring to FIG. 3, a plurality of devices are connected to the plurality of gateways 10, and a network including one gateway and a plurality of devices is referred to as a personal area network (PAN). Networks grouped into one of a number of personal area networks are referred to as domains 100 and 110.

The domains 100 and 110 are connected to the mapping server 200 and 210 and the device management server 400 through the internet network 300. The domain is a sensor network unit managed by an independent mapping server, the domain 100 is managed by the mapping server 200, and the domain 110 is managed by the mapping server 210. The device located in the domain 100 is connected to an adjacent gateway and registered with the mapping server 200 through the connected gateway. Likewise, a device located in the domain 110 is connected to an adjacent gateway and registered with the mapping server 210 through the connected gateway.

The device management server 400 stores identifiers of devices registered in the mapping server, names of devices and home mapping server location information of the devices, and the mapping servers 200 and 210 store domains 100 managed by each mapping server. , The identifier of the device located at 110 and the location information of the device are registered and stored.

A device that registers and stores device identifiers and device location information of a device located in the domain 100, and that has a mapping server 200 that manages identifier-location information of a device located in the domain 100 located in the domain 100. It is referred to as the home mapping server. Meanwhile, the identifier and device location information of the device located in the domain 110 are registered and stored, and the mapping server 210 managing the identifier-location information of the device located in the domain 110 is located in the domain 110. Refers to as the home mapping server of the device. The mapping server 200 becomes an external mapping server for a device located in the domain 110, and the mapping server 210 becomes an external mapping server for a device located in the domain 100.

When a device moves to a personal area network of an external mapping server, the external mapping server registers and stores the identifier and location information of the moved device in the external mapping server. Change from the gateway of the connected personal area network to the gateway of the connected personal area network. The external mapping server inquires the location information of the home mapping server of the mobile device in the device management server 400 based on the identifier of the mobile device and informs the location information of the changed device to the home mapping server of the mobile device. The home mapping server updates only the location information to the gateway of the personal area network to which the mobile device is mobile connected without changing the identifier of the mobile device.

Here, the device is defined as a mobile network (MR) in which a sensor node or a plurality of sensor nodes are connected to a mobile router, which is the same below.

4 is a system diagram for explaining an example of a device mobility support method according to the present invention, Figure 5 is a device node registered in the external mapping server in the device mobility support method according to the present invention managed by the home mapping server FIG. 4 illustrates a message transmitted and received when moving to a mobile network of a personal area network.

Referring to FIGS. 4 and 5, the sensor node node 1 located in the personal area network PAN1 managed by the external mapping server F-ILMA is a mobile network NEMO of the new personal area network PAN2. In this case, the sensor node node 1 receives the beacon message of the new personal area network PAN2 from the mobile router MR of the mobile network, and the PAN ID of the received beacon message and another existing personal area network ( It compares the PAN ID received in PAN1) and determines that it has moved to the new personal area network. The sensor node then sends a connection request message for broadcasting to the mobile network. In response to the access request message, the mobile router assigns a unique address to the sensor node in the mobile network and transmits a connection response message including the assigned address to the sensor node.

Thereafter, the sensor node transmits a registration request message including a 128-bit sensor node identifier to the mobile router in order to register itself with the home mapping server managing the new personal area network (PAN2) and update the location information (S1). In step S2, the mobile router sends a registration request message to the gateway GW2 of the new personal area network. The gateway GW2 transmits a location update request message including the sensor node identifier and the location information to the home mapping server in order to update the location information of the sensor node in response to the received registration request message (S3). The home mapping server determines whether the sensor node moved to the new personal area network is a sensor node registered in the home mapping server based on the sensor node identifier. If the moved sensor node is registered in the home mapping server, the home mapping server changes the location information of the moved sensor node to the gateway (GW2) of the moved new personal area network, and then sends a location update response message to the new personal area network. The data is sent to the gateway (S8). When the gateway of the new personal area network receives the location update response message, the gateway sends a registration response message to the mobile router (S9), and the mobile router transmits the registration response message to the mobile sensor node again to change the location of the mobile sensor node without changing its identifier. Only the information is changed to the gateway of the personal area network to which the sensor node is currently connected.

However, if the identifier of the mobile sensor node is not registered in the home mapping server, a request for querying the location information of the home mapping server of the mobile sensor node, that is, the external mapping server, is registered based on the identifier of the mobile sensor node. Send an inquiry request message to the device management server (S4), the device management server transmits an inquiry response message including the location information of the external mapping server to which the mobile sensor node is registered in response to the inquiry request message to the home mapping server. (S5).

The home mapping server sends a location change request message for changing the location information of the sensor node to the gateway (GW2) of the new personal area network to the location of the external mapping server included in the inquiry response message (S6). In response to the location change request message, the location information of the mobile sensor node is changed to the gateway GW2 of the new personal area network, and then a location change response message is generated and transmitted to the home mapping server (S7).

The home mapping server receiving the location change response message generates a location update response message and sends it to the gateway GW2 of the new personal area network. The gateway (GW2) receiving the location update response message sends a registration response message to the mobile router (S9), and the mobile router sends a registration response message to the mobile sensor node again (S10), and the mobile sensor node does not change the identifier. Only the location information is changed to the gateway of the personal area network to which the sensor node is currently connected.

6 is a view illustrating an example of a registration request message and a registration response message according to the present invention.

FIG. 6 (a) shows the entire frame format of a registration request message or registration response message when a 6LoWPAN packet is included in an IEEE 802.15.4 frame having a maximum frame size of 127 bytes.

Meanwhile, referring to FIG. 6 (b), the 6LoWPAN packet format included in the network header part is described in detail. The data field according to the response message IDA is included. Herein, the mesh header is a header indicating information for mesh routing, and the 6LoWPAN IP header includes a dispatch header pattern (DSP), a compression header pattern (HC1), and a moving header dispatch pattern (MHD), and includes a registration request message or a registration response message. Header indicating information. The dispatch header is a header indicating information on headers to be located next, and the compression header indicates compression information of an IP header (if HC1) or a UDP header (if HC2). That is, the IP header is compressed to the maximum by the HC1 header dispatch and the UDP header to the HC2 header dispatch.

FIG. 7 illustrates an example of a dispatch header pattern and a compressed header pattern of a 6LoWPAN IP header according to the present invention in more detail.

Referring to the dispatch header pattern of the 6LoWPAN IP header in more detail with reference to FIG. 7A, the dispatch header is defined as a mobile header dispatch indicating a registration request message or a registration response message with one byte. Various patterns of mobile header dispatch may be used depending on the field to which the present invention is applied, which is within the scope of the present invention.

Referring to FIG. 7B, the compression header pattern HC1 of the 6LoWPAN IP header will be described in more detail. The compression header is 1 byte, where the first bit is a prefix prefix bit of the source address, and the second bit. Is the source interface identifier compression bit, the third bit is the destination address prefix compression bit, the destination address interface identifier compression bit, and the fifth bit is the traffic and flow label. label zero) bits, the 6th bit and the 7th bit are the mobile header dispatch bits, and the 8th bit are the HC2 compressed header bits. For example, when '00' is written in the 6th bit and the 7th bit, it indicates the mobile header dispatch, and other data bits may be used to indicate the mobile header dispatch according to the field to which the present invention is applied.

8 is a view for explaining an example of a mobile header dispatch and a data field of a 6LoWPAN IP header according to the present invention in more detail.

Referring to FIG. 8 (a), the mobile header dispatch of the 6LoWPAN IP header will be described in more detail. The mobile header dispatch is a byte, and the first bit is a registration request message or a registration response message identifier bit. For example, if a value of 0 is recorded, it means a registration request message. If a value of 1 is recorded, it means a registration response message. If a value indicating a registration request message is recorded in the identifier bit, the second bit is a sequence number bit, the third bit is a lifetime bit, the fourth bit is a grant request bit, and the fifth bit is a location of a mapping server. Information update request bit, the 6th bit is a bit indicating that the device is a sensor node, the 7th bit is a bit indicating that the device is a mobile router, the 8th bit is a registration request sent from the mobile router to the gateway when the device moves to the mobile network Bit representing the message.

On the other hand, when a value indicating a registration response message is recorded in the identifier bit, the second bit is a sequence number bit, the third bit is an active period bit, and the fourth to eighth bits are bits indicating a state.

Referring to FIG. 8 (b), the data field according to the registration request message includes a sequence number field of 1 byte, an active period field of 1 byte, and a device identifier field of 16 bytes, and the data field according to the registration response message. The sequence number field of 1 byte and the active period field of 1 byte are included. As shown in Fig. 7 (c), the 16-byte device identifier field includes two-byte nationally designated data field, two-byte localized data field, two-byte network specified data field, and two-byte personal area network identification. Data field, 8 bytes of IEEE 802.15.4 MAC address data field.

FIG. 9 shows an example of a name of a device registered in a device management server, a device identifier, and location information of a registration mapping server. FIG. 10 shows before and after sensor node 1 moves to a new personal area network (PAN2). FIG. 11 is an example of location information registered in the home mapping server before / after the sensor node 1 moves to a new personal area network PAN2. As shown in FIG. 10, even if the sensor node 1 moves to a new personal area network (PAN2), only the location information of the sensor node 1 is changed from the position A to the position B in the external mapping server, but the identifier of the sensor node 1 is changed. It doesn't work. Meanwhile, as shown in FIG. 11, even when the sensor node 1 moves to a new personal area network, only the location information of the sensor node is registered and registered in the home mapping server, but the identifier of the sensor node 1 is not changed.

In the mobility management method of a device according to an embodiment of the present invention described with reference to FIG. 4, the sensor node does not directly register and update location information changed by the home mapping server, but the mobile router of the mobile network to which the sensor node has moved. And a network-based device mobility support method in which the gateway GW2 of the personal area network updates and registers the home mapping server instead. Therefore, it is possible to effectively support the mobility of the device in the sensor network having a limited energy source and calculation amount.

Meanwhile, the above-described embodiments of the present invention can be written as a program that can be executed in a computer, and can be implemented in a general-purpose digital computer that operates the program using a computer-readable recording medium.

The computer-readable recording medium may be a magnetic storage medium (for example, a ROM, a floppy disk, a hard disk, etc.), an optical reading medium (for example, a CD-ROM, DVD, etc.) and a carrier wave (for example, the Internet). Storage medium).

Although the present invention has been described with reference to the embodiments shown in the drawings, this is merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

10: gateway
100, 110: domain
200, 210: mapping server
300: Network
400: device management server

Claims (8)

In the method for supporting the mobility of the device in the Internet Protocol version 6 (IPv6) -based sensor network,
When the external device moves to a mobile network located in a personal area network (PAN) of a home mapping server, receiving a location update request message from a gateway managing the mobile network;
Determining whether the external device is an external device registered in an external mapping server based on the external device identifier;
If the external device is an external device registered in an external mapping server, requesting for retrieving location information of the external mapping server in which the external device is registered by transmitting the external device identifier to a device management server;
Transmitting, to the external mapping server, a location change request message including location information of the gateway and the external device identifier and requesting to change the external device location information mapped to the external device identifier to the gateway location; And
Receiving a location change response message of the external device from the external mapping server in response to the location change request message, and transmitting a location update response message to the gateway,
When the external device moves to the mobile network, the external device transmits a registration request message for registering movement information of the external device to the home mapping server or an external mapping server to the mobile router. Sends a registration request message back to the gateway managing the mobile network;
When the gateway managing the mobile network receives the location update response message, the gateway sends a registration response message to the mobile router indicating that the registration of the mobile information of the external device has been completed, and the mobile router again registers the response message. Transmitting the data to the external device. The method of claim 1,
The Internet Protocol version 6 based sensor network is a 6LoWPAN (IPv6 Low-power Wireless Personal Area Network). The method of claim 2, wherein when the external device is registered with a home mapping server,
The location information of the external device mapped to the external device identifier is changed to a gateway location managing a mobile network to which the external device is mobilely connected.
And transmitting a location update response message directly to a gateway managing a mobile network to which the external device is connected. The device management server of claim 2, wherein the device management server comprises:
And an identifier of the external device and location information of a home mapping server or an external mapping server to which the external device is registered. The method of claim 4, wherein the external mapping server or home mapping server
Stores location information mapped to the external device identifier and the external device identifier,
And when receiving the location change request message, changing location information of the external device mapped to the external device identifier to a location of the gateway. The method of claim 5, wherein the registration request message or registration response message
A dispatch header pattern field, a compressed header field, a mobile header dispatch field, and a data field,
The dispatch header pattern field stores pattern data indicating that the mobile header dispatch is added.
In the mobile header dispatch field, identification data for distinguishing a registration request message or a registration response message is stored.
And a data field including a registration request message or data corresponding to the registration response message is added to the mobile header dispatch field according to the identification data. The method according to claim 6,
The dispatch header pattern field, the compressed header field, and the mobile header dispatch field are 1 byte, 1 byte, and 1 byte in size, respectively, and the data field is 18 bytes for a registration request message and 2 bytes for a registration response message. To support mobility of devices. The method of claim 7, wherein
The sixth and seventh bits of the compressed header field store data indicating a mobile header dispatch added after the compressed header field.
Identification data is stored in a first bit of the mobile header dispatch field;
And 16 bytes of the data field of the registration request message store data representing an identifier of the device.

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