KR100646748B1 - Mesh network configuration method for supporting ad hoc networking - Google Patents

Abstract

A mesh network configuration method for supporting ad hoc networking is provided to effectively transmit data even when mobile terminals move fast. In a method for configuring an ad hoc network by using a MAC frame that additionally defines a mesh interval including a network control field for providing synchronization and registration information, a subscriber station serving as a mesh base station transmits a network configuration message by using the network control field. A subscriber station, which has received the mesh network configuration message, is synchronized with the mesh base station by using information included in the mesh network configuration message and registered.

Description

Mesh Network Configuration Method for Supporting Ad Hoc Networking

1 is a configuration diagram of an embodiment of a wireless Ad Hoc network;

2 is a diagram illustrating an embodiment of a mesh base station cluster of FIG. 1;

3A illustrates an embodiment of a MAC frame structure according to the present invention;

3b is an operation timing diagram of a centralized scheduling method;

4 is a diagram illustrating a subtree structure of a MAC frame according to the present invention;

FIG. 5A is a diagram illustrating a procedure of registering a new subscriber station with a mesh base station in an Ad Hoc network; FIG.

5b is another embodiment illustrating a procedure of a new subscriber station registering with a mesh base station in an Ad Hoc network;

FIG. 5C is a diagram illustrating a procedure for registering a subscriber station outside a mesh base station in an ad hoc network with a mesh base station; FIG.

FIG. 6A is a diagram illustrating a case where a subscriber station serving as a regular subscriber station moves; FIG.

6B is a flowchart illustrating a network configuration method when a subscriber station within a radius of a mesh base station moves;

6c is a flowchart illustrating a network configuration method when a subscriber station moves outside a radius of a mesh base station;

FIG. 7A is a diagram illustrating a case where a subscriber station serving as a submesh base station moves; FIG.

7B is a flowchart illustrating a network configuration method when a subscriber station serving as a submesh base station moves;

8A is a diagram illustrating an example of a case where a subscriber station serving as a mesh base station moves;

8B is a flowchart illustrating a network configuration method when a subscriber station serving as a mesh base station moves;

8C is a flowchart illustrating a network configuration method of a subscriber station (sub mesh base station or general subscriber station) when a subscriber station serving as a mesh base station moves;

9A is a diagram illustrating an embodiment of a network for explaining a handoff method of a mesh base station;

9b is a flowchart illustrating a handoff method of a mesh base station according to the present invention;

10A is a diagram illustrating an exemplary network configuration of a handoff method when two different networks overlap each other.

10b is a flowchart illustrating a handoff method when two different networks overlap;

FIG. 10C is an embodiment diagram illustrating a case where two subscriber stations interfere with each other. FIG.

* Explanation of symbols for the main parts of the drawings

300: competition section 310: uplink section

320: downlink section 330: mesh section

The present invention relates to a mesh network configuration method for supporting Ad-Hoc networking between mobile terminals based on IEEE 802.16. More specifically, mobility is granted to terminals in the IEEE 802.16 standard designed to be suitable for fixed terminals. In this case, the present invention relates to a mesh network configuration method in which mobility-provided terminals form an ad hoc network.

The IEEE 802.16 Working Group (WG) of the United States has completed the first standard, IEEE 802.16 WirelessMANTM, for broadband fixed wireless communications systems. Since then, new standards, IEEE 802.20 and IEEE 802.16e, have been enacted to reflect the market demand for mobility. However, since IEEE 802.16a is a standard designed for fixed terminals, the requirements of the Ad Hoc network to enable communication between mobile terminals are not reflected.

A wireless ad-hoc network is a temporary network that is autonomously configured between terminals without the aid of a base network device such as a base station or a base station (BS). Ad-hoc terminals communicate with each other using an air interface, thereby causing physical limitations in transmission distance. For this reason, in order to communicate between terminals that are not located in the physical communication area, a multi-hop communication method via terminals located in the middle should be used. That is, in order to communicate between terminals not located in the physical communication area, a multi-hop communication method through a terminal in the logical communication area should be used.

For communication between terminals constituting the wireless Ad-hoc network, each terminal detects a wireless channel state and uses a MAC (Media Access Control) protocol to access the wireless channel based on the terminal. In order for one terminal to transmit data through a wireless channel, first, whether a target terminal exists in a physical communication area or a logical communication area is determined. Determination of this communication area is obtained by periodic network configuration checks before sending data messages. When the destination terminal exists in the logical communication area, the source terminal of the data transmission confirms the state of each terminal to be passed through and then performs data transmission using the control message and the data message.

As described above, the conventional IEEE 802.16 is a system of PMP (Point to Multipoint) structure made on the assumption that there is no movement of the terminal around the metropolitan. In addition, a mesh structure is designed to selectively transmit data using a wireless Ad-hoc network communication system, which has a limitation in that it is not applicable to a mobile terminal because the terminal is fixed.

The present invention has been proposed to solve the above problems, and newly defines a MAC frame structure for supporting Ad Hoc networking between terminals to which mobility is granted in the IEEE 802.16 standard in which terminals are fixed, and uses the defined MAC frame structure. Accordingly, an object of the present invention is to provide a mesh network configuration method in which terminals register, move, and handoff.

Other objects and advantages of the present invention can be understood by the following description, and will be more clearly understood by the embodiments of the present invention. Also, it will be readily appreciated that the objects and advantages of the present invention may be realized by the means and combinations thereof indicated in the claims.

In order to achieve the above object, the present invention provides a method for configuring an Ad Hoc network using a MAC frame structure in which a mesh section including a network control field for providing synchronization and registration information is additionally provided. Transmitting a network configuration message by using a network control field (hereinafter referred to as a mesh base station); And the subscriber station receiving the mesh network configuration message synchronizes and registers with the mesh base station using the information in the mesh network configuration message.

In addition, the present invention provides an Ad Hoc network configuration method when a subscriber station (mesh base station or sub-mesh base station) moves, the method comprising: moving a subscriber station; Determining whether a network configuration message is received from an upper subscriber station (mesh base station or sub-mesh base station) previously registered by the mobile subscriber station; Performing new registration when a network configuration message is not received from a pre-registered upper subscriber station; And maintaining an existing registration when a network configuration message is received from a pre-registered upper subscriber station.

The present invention also provides a method for configuring an ad hoc network when a mesh base station moves, the method comprising: moving a subscriber station serving as a mesh base station; Deleting the subscriber station from the registered subordinate subscriber station not receiving the network configuration message from the record; And switching to a general subscriber station to perform a new registration if a network configuration message is not received from the lower subscriber station.

In addition, the present invention is an Ad Hoc network configuration method when a mesh base station is handed off, and a subscriber station (hereinafter referred to as a mesh base station) serving as a mesh base station transmits a network configuration message to subordinate subscriber stations. Informing off start; Transmitting, by the mesh base station, information necessary for handoff to a subscriber station to be handed off; And transmitting, by the mesh base station, the handoff end information to the lower subscriber stations after receiving the response message from the subscriber station to be handed off.

The above objects, features and advantages will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, whereby those skilled in the art may easily implement the technical idea of the present invention. There will be. In addition, in describing the present invention, when it is determined that the detailed description of the known technology related to the present invention may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a configuration diagram of an embodiment of a wireless ad hoc network.

As shown in FIG. 1, the ad hoc network includes a base station (BS) 110, a mesh base station (MBS) 121, and a terminal 122. 121 configures the mesh base station cluster 120 with the terminals 122 connected in one hop, and the mesh base station 121 may directly communicate with the base station 110 in one hop.

FIG. 2 is a diagram illustrating an embodiment of the mesh base station cluster of FIG. 1.

As illustrated in FIG. 2, the mesh base station cluster 200 includes a mesh base station 210, a sub mesh base station 220 (child MBS 220), and a subscriber station 230 (which has only pure terminal function).

The mesh base station 210 is a central node for ad hoc networking in a system employing the IEEE 802.16a mesh mode, and operates as a basic frame to schedule resources to subscriber stations 230 within a radius.

In addition, the sub-mesh base station 220 is a sponsor node, and receives resources from the mesh base station 210 or a higher sub-mesh base station, and includes subscriber stations within its radius (including subscriber stations existing outside the radius of the mesh base station). Allocate resources to.

Meanwhile, the subscriber stations 230 and 24 request resources belonging to the mesh base station 210 or the sub mesh base station 220 and perform ad hoc communication using the allocated resources.

3A illustrates an embodiment of a MAC frame structure according to the present invention.

As shown in FIG. 3A, the MAC frame according to the present invention includes a contention period 300, an uplink period 310, a downlink period 320, and a mesh phase 330. It consists of.

The base station and the mesh base station 210 communicate using the existing IEEE 802.16a scheme as it is, using the contention period 300, the uplink period 310, and the downlink period 320 among the MAC frames of FIG. 3. .

The mesh base station 210 and the subscriber station 220 communicate using the mesh period 330 of FIG. 3A. In this case, the mesh section 330 of FIG. 3A includes a network frame and a scheduling frame. The network frame is composed of a network control subframe and a data subframe, and the scheduling frame is composed of a schedule control subframe and a data subframe. The network frame is used periodically once after the scheduling frame is used N times. That is, when the ad hoc network is in the form of a mesh topology and the mesh topology changes as the subscriber station moves, the network and schedule interval repetition is determined according to the changed period.

The network control subframe consists of a network entry 331 and a network config 332. The network entry 331 is composed of a preamble, an MSH-NENT 341, and a guard symbol and used to synchronize a new node (subscriber station). The network config 332 is composed of a preamble, an MSH-NCFG 343, and a guard symbol, which is used to acquire location information of a subscriber station. Each field will be described in detail as follows.

Mesh Network Entry (MSH-NENT) 341 is used to obtain synchronization and initial network entry in the mesh network.

Mesh Network Configuration (MSH-NCFG) 343 is used to provide a basic level of communication between different nodes in the vicinity of the network and is also used in response to the MSH-NENT 341 request message. All nodes of the base station and subscriber station in the mesh network send an MSH-NCFG 343 message. The location information can be known from the arrival time difference of the transmitted MSH-NCFG 343 message.

The scheduling control subframe consists of Central sched. (336), Central conf. (337), and Dist sched. (338). Central sched. (336) consists of preamble, MSH-CSCF (342), guard symbols, Central conf. (337) consists of preamble, MSH-CSCH (344), guard symbols, Dist sched. (338) Is composed of a preamble, an MSH-DSCH 345, and a guard symbol. Each field will be described in detail as follows.

Mesh Centralized Scheduling Configuration (MSH-CSCF) 342 is a message sent when centralized scheduling is used in mesh base station 210, and mesh base station 210 delivers the MSH-CSCF 342 message to all neighbor nodes. do. In addition, all nodes transmit the MSH-CSCF 342 message to neighboring nodes when their location information is changed. At this time, the nodes transmit the message according to the index number (index number specified) of the MSH-CSCF 342 message so that a collision between nodes does not occur.

Mesh Centralized Scheduling (MSH-CSCH) 344 is created by mesh base station 210 when centralized scheduling is used. The mesh base station 210 determines the data transmission order of each subscriber station and transmits an MSH-CSCH 344 message including the order information to all nodes.

Mesh Distributed Scheduling (MSH-DSCH) 345 is transmitted in mesh mode when distributed scheduling is used. In equivalent distributed scheduling, all nodes send an MSH-DSCH 345 message to inform all neighbors of their schedule information. The time it takes to transmit this is determined by the same algorithm that was used in the MSH-NCFG 343.

3B is an operation timing diagram of a centralized scheduling scheme.

4 is a diagram illustrating an exemplary subtree structure of a MAC frame according to the present invention. A network configuration method of the tree structure will now be described with reference to FIG. 4.

First, a mobile subscriber station including a mesh base station (MBS) sends an MSH-NCFG 343 message (network configuration message) at a time at which transmission is possible in consideration of collision with neighboring subscriber stations and a base station for network configuration.

The subscriber station sending the MSH-NCFG 343 message replaces its MSH-NCFG 343 transmission interval with a discovery interval at regular intervals to hear the response of the mobile subscriber station outside the cell. After synchronizing the mobile subscriber station out of the cell through this process, the subscriber station is configured as a child mesh base station (Child MBS). The configured sub-mesh base station (Child MBS) registers a mobile subscriber station out of the cell by using a predetermined period (PHY tr.burst from ss * j) in a data subframe allocated from the mesh base station MBS.

After completion of the registration process, when the mobile subscriber station outside the cell requests interval allocation to the child mesh base station (Child MBS) for data transmission with another mobile subscriber station, the child mesh base station (Child MBS) receives data in a scheduling frame. A transmission interval of a subframe is allocated, and this interval is allowed to the mobile subscriber station as an interval for data transmission. That is, since the sub-mesh base station allocates channels to lower mobile subscriber stations in a tree structure as illustrated in FIG. 4, the Ad Hoc network can be extended based on the IEEE 802.16a mesh base station mode.

FIG. 5A is a diagram illustrating a procedure of registering a new subscriber station with a mesh base station in an ad hoc network, and illustrates a procedure of registering a subscriber station with a mesh base station one hop from the mesh base station.

As shown in FIG. 5A, the mesh base station (MBS) transmits the MSH-NCFG message aperiodically using the MSH-NCFG 343 interval (transmission time is determined by the specification procedure itself). The new subscriber station (subscriber station 1) synchronizes using information such as a time stamp and frame number in its received MSH-NCFG message and generates a list of neighboring subscriber stations (501).

The new subscriber station performs a procedure for becoming a regular node after receiving the MSH-NCFG message sent by the mesh base station. That is, the new subscriber station transmits the MSH-NENT message (network entry message) to the mesh base station using the MSH-NENT 341 interval (502), and the mesh base station transmits the MSH-NCFG message to the new subscriber station to the network. Open the entry (503).

Next, the new subscriber station transmits a privacy key management request (PKM-REQ) message (authentication request and authentication information) to the base station BS via the mesh base station for regular node authentication (504). After receiving an authentication response (PKM-RSP message) from the base station (505), the new subscriber station sends a REG-REQ (Registration Request) message to the base station for regular node registration (506). Upon receiving the REG-RSP message, the new subscriber station sends an MSH-NENT message to the mesh base station to notify the network entry procedure deadline (507, 508), receives the MSH-NENT message from the mesh base station and becomes a regular node in the network ( 509). Thereafter, the subscriber station transmits the MSH-NCFG message aperiodically to inform the mesh base station of its surrounding information, and the mesh base station and other subscriber stations update their routing tables.

FIG. 5b is another exemplary diagram illustrating a procedure of registering a new subscriber station with a mesh base station in an ad hoc network. In FIG. 5a, a new subscriber station (subscriber station 1) registers with a mesh base station one hop distance from the mesh base station. The other subscriber station (subscriber station 2) registers with the mesh base station. That is, the other subscriber station receives both the MSH-NCFG message from the mesh base station and the subscriber station of FIG. 5A and registers with the mesh base station in the same manner as the procedure of FIG.

FIG. 5C is a diagram illustrating a procedure for registering a subscriber station outside a mesh base station to an mesh base station in an Ad Hoc network, and illustrating a procedure for registering a subscriber station with a mesh base station two hops away from the mesh base station.

In FIG. 5A or FIG. 5B, the subscriber station registered with the mesh base station is set as a sub mesh base station (Child MBS) and transmits an MSH-NCFG message. The subscriber station (subscriber station 3) located outside the mesh base station area receives the MSH-NCFG message from the sub-mesh base station and performs the same procedure as that of FIG. 5a or 5b to register with the sub-mesh base station. At this time, the subscriber station transmits and receives a message through the sub-mesh base station and the mesh base station for authentication and registration with the base station BS.

In summary, when a new subscriber station is powered on and scans the channel for a period of time, if there are no nodes around it to receive any information in the mesh frame, that is, if it does not receive MSH-NCFG messages for a period of time outside of the mesh base station radius, It will act as a mesh base station. When acting as a mesh base station, it starts to send network frames and scheduling frames.

On the other hand, a new subscriber station powered on within the radius of the mesh base station receives a message from the mesh base station and registers as a regular subscriber station. At this time, if there is at least one other regular subscriber station within the mesh base station radius, the registered regular subscriber station sends an MSH-NCFG message to inform neighboring regular subscriber stations of its ID. The registered regular subscriber station receives an MSH-NCFG message from neighboring regular subscriber stations and configures a routing table. In order to transmit the data, the registered regular subscriber station makes a request to the mesh base station within a scheduling frame, receives the scheduling from the mesh base station, and transmits the data.

In addition, a new subscriber station powered out of the radius of the mesh base station registers as a regular regular subscriber station since it receives an MSH-NCFG message when there is a neighboring regular subscriber station or sub-mesh base station in the vicinity. At this time, the neighboring regular subscriber station is selected as a sub-mesh base station or controlled by an existing sub-mesh base station.

Next, a description will be given of the movement of subscriber stations in the Ad Hoc network. As the subscriber station moves in the ad hoc network, it may be divided into a case where the subscriber station moves when serving as a regular subscriber station, and when the subscriber station serves as a mesh base station (including a sub mesh base station).

6A, 6B, and 6C, a case in which a subscriber station serving as a regular subscriber station moves will be described.

FIG. 6A is a diagram illustrating a case in which a subscriber station serving as a regular subscriber station moves. When a subscriber station serving as a regular subscriber station moves, it can be divided into a case where a subscriber station within a mesh base station (MBS) radius moves and a subscriber station located outside a mesh base station radius moves.

First, a case in which a subscriber station within a radius of a mesh base station (MBS) moves will be described.

When the subscriber station 601 of the subscriber station shown in FIG. 6A moves to a position 602 or 603 outside the radius of the mesh base station 606, if the MSH-NCFG message received from the neighboring subscriber station is confirmed, the MSH- received from the mesh base station 606 is determined. Since there is no NCFG message, the existing ID is discarded and a neighbor neighboring subscriber station or submesh base station 607 is selected to apply for a new ID.

On the other hand, if the subscriber station 601 moves to position 604 within the radius of the mesh base station 606, there is no change since there is an MSH-NCFG message received from the mesh base station 606.

Next, a case where a subscriber station located outside the radius of the mesh base station moves is described as follows.

MSH-NCFG message received from the sub-mesh base station 607 when the subscriber station 605 of the subscriber station shown in FIG. 6A moves out of the radius of the mesh base station 606 and the sub-mesh base station 607 and checks the received MSH-NCFG message. Since the existing ID is discarded, the neighboring subscriber station or sub-mesh base station is selected to apply for a new ID. That is, if there is another sub-mesh base station sending the MSH-NCFG message, the ID is newly registered to the sub-mesh base station, and if not, the sub-mesh base station is requested by randomly selecting among neighboring subscriber stations.

On the other hand, when the subscriber station 605 moves to a position 602 or 603 within the radius of the existing sub-mesh base station 607, there is no change since there is an MSH-NCFG message received from the sub-mesh base station.

In addition, when the subscriber station 605 moves to the position 604 within the radius of the mesh base station 606, since there is an MSH-NCFG message received from the mesh base station 606, the existing ID is discarded and a new ID is applied to the mesh base station 606. Register.

6B is a flowchart illustrating a network configuration method when a subscriber station within a mesh base station radius moves.

As shown in FIG. 6B, the subscriber station in mesh base station 606 first moves (601b). The subscriber station then receives the MSH-NCFG message to determine if there is an MSH-NCFG message received from mesh base station 606 (602b).

If there is an MSH-NCFG message received from mesh base station 606, the subscriber station maintains an existing registration (603b).

If there is no MSH-NCFG message received from mesh base station 606, the subscriber station attempts a new registration (604b). That is, the existing ID is discarded and an adjacent neighbor subscriber station or sub-mesh base station 607 is selected to apply for a new ID.

6C is a flowchart illustrating a network configuration method when a subscriber station moves outside a radius of a mesh base station.

As shown in FIG. 6C, first the subscriber station outside the mesh base station radius moves (601c). The subscriber station then determines (602c) if there is an MSH-NCFG message received from the mesh base station.

If there is an MSH-NCFG message received from the mesh base station, the existing ID is discarded and a new ID is applied and registered (603c). If there is no MSH-NCFG message received from the mesh base station, the MSH-NCFG message is received from the sub-mesh base station. 604c.

If there is an MSH-NCFG message received from the submesh base station, the subscriber station maintains an existing registration (605c), and if there is no MSH-NCFG message received from the submesh base station, the subscriber station receives from another mesh base station or submesh base station. It is determined whether there is an MSH-NCFG message (606c).

If there is a mesh base station or sub-mesh base station sending an MSH-NCFG message, the ID is newly registered with the mesh base station or sub-mesh base station (607c). If not, the sub-mesh base station is requested (608c) by randomly selecting among neighboring subscriber stations.

Next, a case in which the subscriber station moves while serving as a sub-mesh base station will be described with reference to FIGS. 7A and 7B.

FIG. 7A is a diagram illustrating a case where a subscriber station serving as a submesh base station moves. FIG.

When the sub-mesh base station 709 of FIG. 7a moves to the position 704 within the radius of the mesh base station 710, when the sub-mesh base station 709 does not receive the MSH-NCFG message of the subscriber station registered to itself for a predetermined time, the information of the corresponding subscriber station is deleted. If there is no subscriber station registered with him after deletion, he switches to a regular subscriber station. At this time, the subscriber station 707 located within the radius of the sub-mesh base station 709 and located out of the radius after the movement of the sub-mesh base station 709 does not receive the MSH-NCFG message of the sub-mesh base station 709, thus joining the neighbor. Receives MSH-NCFG message from the own stations, selects new sub-mesh base station and registers ID.

Meanwhile, when the sub-mesh base station 709 of FIG. 7a moves to a location 702 or 703 outside the radius of the mesh base station 710, the sub-mesh base station 710 does not receive the MSH-NCFG message from the mesh base station 710, thereby giving up the sub-mesh base station role and being a regular subscriber station. Switch to The switched regular subscriber station receives the MSH-NCFG message from the neighboring subscriber station or another sub mesh base station, selects a new sub mesh base station and registers an ID. In addition, the subscriber stations 706 and 707, which received the MSH-NCFG message from the sub-mesh base station 709 before switching, do not receive the MSH-NCFG message from the sub-mesh base station 709, so that the neighboring subscriber station or another sub-mesh base station. The MSH-NCFG message is received from the new sub-mesh base station and the ID is registered.

In the above-described process, the role termination condition of the sub-mesh base station is when the MSH-NCFG message of the lower subscriber station is not received, or the MSH-NCFG message of the upper mesh base station or the upper sub-mesh base station is not received for a predetermined time. At this time, the maximum time to wait for the MSH-NCFG message is the time to receive the network control subframe N times.

7B is a flowchart illustrating a network configuration method when a subscriber station serving as a sub-mesh base station moves.

As shown in FIG. 7B, first, a subscriber station (hereinafter referred to as a sub-mesh base station) that serves as a sub-mesh base station moves (701b). Next, the sub-mesh base station determines whether there is an MSH-NCFG message received from the mesh base station or the higher sub-mesh base station (702b).

If there is no MSH-NCFG message received from the mesh base station or higher sub-mesh base station, the sub-mesh base station attempts new registration (705b).

If there is an MSH-NCFG message received from the mesh base station or higher sub-mesh base station, the sub-mesh base station determines whether there is an MSH-NCFG message from the lower tree subscriber station (703b).

If there is no MSH-NCFG message received from the lower tree subscriber station, the sub mesh base station terminates the role of the sub mesh base station and attempts new registration with the regular subscriber station (705b).

If there is an MSH-NCFG message received from a sub-tree subscriber station, the sub-mesh base station deletes from the record the subscriber station not transmitting the MSH-NCFG message from its registered subscriber station and maintains the existing sub-mesh base station role. (704b).

Next, a case in which the subscriber station moves while serving as a mesh base station will be described with reference to FIGS. 8A, 8B, and 8C.

8A is a diagram illustrating an example of a case where a subscriber station serving as a mesh base station moves.

If the mesh base station 801 of FIG. 8A does not receive the MSH-NCFG message of the regular subscriber station or sub-mesh base station registered to itself for a predetermined time after the movement, the mesh base station 801 deletes the regular subscriber station or sub-mesh base station. At this time, since the lower regular subscriber stations do not receive the MSH-NCFG message of the mesh base station 801 registered for the predetermined period, they search for a new sub-mesh base station and newly register. In addition, since the lower sub-mesh base stations do not receive the MSH-NCFG message of the mesh base station 801 registered by the lower sub-mesh base stations for a predetermined period, the lower sub-mesh base stations switch to the regular subscriber station. On the other hand, the subscriber station or sub-mesh base station, which was outside the radius of the mesh base station 801 before the mesh base station 801 moved, but is located within the radius of the mesh base station 801 due to the movement of the mesh base station 801, is transferred to the mesh base station 801. Register new.

8B is a flowchart illustrating a network configuration method when a subscriber station serving as a mesh base station moves.

As shown in FIG. 8B, the mesh base station moves first (801b). The moved mesh base station determines whether all subtree MSH-NCFG messages are received for a predetermined time (802b).

If all the subtree MSH-NCFG messages are received, the existing record is maintained (803b) and the mesh base station role (805b).

If the MSH-NCFG message is not received from some of the subtree subscriber stations registered to the subscriber station, the subscriber station deletes the record of the subscriber station (804b) and maintains the role of the mesh base station (805b).

8C is a flowchart illustrating a method for configuring a network of a subscriber station (sub mesh base station or general subscriber station) when a subscriber station serving as a mesh base station moves.

As shown in FIG. 8C, the mesh base station moves (801c) first. The sub-mesh base station or the general subscriber station determines (802c) whether the MSH-NCFG message is received from the mesh base station for a predetermined time.

If the MSH-NCFG message is received from the mesh base station, the subscriber station remains in the previous state (803c), and if the MSH-NCFG message is not received from the mesh base station, performs a new registration procedure (804c).

Next, a general handoff method of the mesh base station will be described.

9A is a diagram illustrating an embodiment of a network for handoff of a mesh base station, and FIG. 9B is a flowchart illustrating a handoff method of a mesh base station according to the present invention.

The mesh base station performs a handoff to a subscriber station having the most subscribers in a one-hop relationship among neighboring subscriber stations, or a handoff to a subscriber station having the strongest power among neighboring subscriber stations. do.

As shown in FIG. 9B, mesh base station 901a notifies neighbor subscriber stations by using an MSH-NCFG message to start handoff (901b).

Sub-mesh base stations then forward handoff start information to subscriber stations of the lower node (902b). The subscriber stations that receive the handoff start notification message do not send an MSH-NCFG message and wait until the handoff ends.

The mesh base station 901a selects one subscriber station from neighboring subscriber stations and transmits necessary information (903b). At this time, the mesh base station 901a selects a subscriber station having the largest number of subscribers having a 1-hop relationship among neighboring subscriber stations as described above, or has the strongest power among the neighboring subscriber stations. Select the subscriber station as the handoff target.

The selected subscriber station sends an acknowledgment (Ack.) Message to the mesh base station 901a after receiving the handoff related information (904b).

The mesh base station 901a notifies the neighboring subscriber stations of the handoff end information (905b), and the selected subscriber station serves as a new mesh base station. At this time, the handoff end information includes the ID of the selected subscriber station.

The existing subscriber stations register with the new mesh base station 906b.

Next, a handoff method when two different networks overlap with reference to FIGS. 10A, 10B and 10C will be described.

FIG. 10A is a diagram illustrating an embodiment of a handoff method when two different networks overlap, and FIG. 10B is a flowchart illustrating a handoff method when two different networks overlap.

When the subscriber station 1001a of FIG. 10A receives different MSH-NCFG messages from mesh base station A and mesh base station B, a handoff request is made to each mesh base station to form a new network. A detailed description with reference to FIG. 10B is as follows.

As shown in FIG. 10B, the subscriber station 1001a makes a handoff request to the currently registered mesh base station A (1001b).

Mesh base station A informs subscriber stations in its one hop relationship of the start of the handoff (1002b). At this time, the subscriber stations receiving the handoff start notification message wait until the handoff ends without sending an MSH-NCFG message.

Subsequently, the mesh base station A transmits information necessary for handoff to the subscriber station 1001a (1003b), and the subscriber station 1001a receives an acknowledgment (Ack.) Message after receiving the handoff related information transmitted by the mesh base station A. Transmit (1004b). At this time, mesh base station A waits to receive a handoff end notification message after receiving the response message from subscriber station 1001a.

The subscriber station 1001a requests the ID registration from the unregistered mesh base station B (1005b), and after registering, the subscriber station 1001a requests a handoff from the mesh base station B (1006b).

Mesh base station B then informs subscriber stations in its one hop relationship of the start of the handoff (1007b). At this time, the subscriber stations receiving the handoff start notification message wait until the handoff ends without sending an MSH-NCFG message.

Subsequently, the mesh base station B transmits information necessary for handoff to the subscriber station 1001a (1008b), and the subscriber station 1001a receives an acknowledgment message after receiving the handoff related information transmitted by the mesh base station B. Transmit (1009b). At this time, the mesh base station B waits to receive the handoff end notification message after receiving the response message from the subscriber station 1001a.

The subscriber station 1001a then broadcasts the handoff end notification message and then acts as a new mesh base station (1010b).

Subsequently, the mesh base stations A and B broadcast the handoff end notification message, terminate the role of the mesh base station, and request registration with the new mesh base station (1011b).

Meanwhile, FIG. 10C is a diagram illustrating an example in which two subscriber stations interfere with each other. As shown in FIG. 10C, when the subscriber stations 1001c and 1002c interfere with each other, the subscriber station 1001c or the subscriber station 1002c. A request for a handoff must be made by integrating into one network or interfering with a subscriber station 1001c or 1002c. In this case, it is unreasonable to construct the network again by performing a handoff centered on the interfering subscriber station as shown in the right side of FIG. In other words, the number of subscriber stations that will exist in one hop centering on the new mesh base station and the number of multi-hops is often generated. Therefore, it is desirable for the affected subscriber stations to move to where they do not interfere with themselves. That is, it is reasonable to enforce a handoff when a subscriber station in one hop receives two or more MSH-NCFG messages.

The present invention described above is capable of various substitutions, modifications, and changes without departing from the technical spirit of the present invention for those skilled in the art to which the present invention pertains. It is not limited by the drawings.

As described above, the present invention extends IEEE 802.16, which is designed based on a fixed terminal, to a mobile terminal to allow an ad hoc network configuration between mobile terminals, thereby enabling efficient data transmission even when the terminals move at high speed. have.

Claims (12)

A method of configuring an ad hoc network using a MAC frame in which a mesh section including a network control field for providing synchronization and registration information is additionally defined. Transmitting, by a subscriber station acting as a mesh base station (hereinafter referred to as a mesh base station) a network configuration message using the network control field; And A subscriber station receiving a mesh network configuration message synchronizes and registers with the mesh base station using information in the mesh network configuration message. Network configuration method comprising a. The method of claim 1, The subscriber station registered with the mesh base station transmitting a network configuration message to inform neighboring subscriber stations of its ID; And A subscriber station registered to a mesh base station receives a network configuration message from the neighboring subscriber station to configure a routing table. Network configuration method further comprising. The method of claim 1, Transmitting a network configuration message by a subscriber station (hereinafter referred to as a sub-mesh base station) registered with the mesh base station; And A subscriber station outside a radius of a mesh base station receives a network configuration message transmitted by the sub-mesh base station to synchronize and register with the sub-mesh base station. Network configuration method further comprising. The method of claim 1, A subscriber station sending a network entry open message to the mesh base station using the network control field; A subscriber station transmitting an authentication management request message to the general base station via the mesh base station; After the subscriber station receives the authentication response message from the general base station, sending a registration request message to the general base station; And The subscriber station transmitting a network entry close message to the mesh base station after receiving a registration response message from the general base station Network configuration method comprising a. An ad hoc network configuration method using a MAC frame further defining a mesh section including a network control field (a network configuration message is transmitted and received through the network control field) for providing synchronization and registration information. The subscriber station moves; Determining whether a network configuration message is received from an upper subscriber station (mesh base station or sub-mesh base station) previously registered by the mobile subscriber station; Performing new registration when a network configuration message is not received from a pre-registered upper subscriber station; And Maintaining an existing registration when a network configuration message is received from a previously registered higher subscriber station Network configuration method comprising a. The method of claim 5, The mobile subscriber station is a general subscriber station, Performing the new registration, When a network configuration message is received from another upper subscriber station, newly registering with the upper subscriber station; And Requesting a sub-mesh base station by randomly selecting among neighboring subscriber stations when no network configuration message is received from another upper subscriber station; Network configuration method comprising a. The method of claim 5, The mobile subscriber station is a sub-mesh base station, The existing registration maintenance step, Deleting, from the record, the subscriber station among the lower subscriber stations registered to the subscriber station which does not transmit the network configuration message; And If the network configuration message is not received from all subordinate subscriber stations registered to the subscriber, switching to the general subscriber station to perform new registration Network configuration method comprising a. An ad hoc network configuration method using a MAC frame further defining a mesh section including a network control field (a network configuration message is transmitted and received through the network control field) for providing synchronization and registration information. Moving by a subscriber station serving as a mesh base station; Deleting the subscriber station from the registered subordinate subscriber station not receiving the network configuration message from the record; And If no network configuration message is received from the subordinate subscriber station, switching to the general subscriber station to perform a new registration Network configuration method comprising a. The method of claim 8, A lower subscriber station determining whether a network configuration message is received from the mesh base station for a predetermined time; Maintaining a previous state when a network configuration message is received from the mesh base station; And Performing a new registration if a network configuration message is not received from the mesh base station Network configuration method further comprising. An ad hoc network configuration method using a MAC frame further defining a mesh section including a network control field (a network configuration message is transmitted and received through the network control field) for providing synchronization and registration information. A subscriber station (hereinafter referred to as a mesh base station) serving as a mesh base station transmitting a network configuration message to the lower subscriber stations to indicate the start of handoff; Transmitting, by the mesh base station, information required for handoff to a subscriber station to be handed off; And The mesh base station receiving the response message from the subscriber station to be handed off and transmitting the handoff termination information to the lower subscriber stations; Network configuration method comprising a. The method of claim 10, The mesh base station is a subscriber station to be handed off, wherein the subscriber station having the largest number of subscriber stations in a one-hop relationship or the strongest subscriber station is selected. The method of claim 11, The handoff end information is, And the ID of the subscriber station to serve as a new mesh base station.

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