KR100866567B1 - Method for managing path by encapsulation in multi-hop wireless network - Google Patents

Abstract

The path management method using encapsulation in a multi-hop wireless network according to the present invention relates to a path management method suitable for a centrally controlled multi-hop wireless network capable of managing a path in a simple manner by encapsulating packets transmitted and received between a base station and a relay station. As a simple method through packet encapsulation, it is easy to implement and uses less resources than the conventional ad-hoc method, thereby improving network performance.

Description

Method for managing path by encapsulation in multi-hop wireless network

1 is a view showing a configuration example of a centrally controlled multi-hop wireless network to which the present invention is applied.

FIG. 2 is a diagram of a tree structure simplifying the connection relationship of FIG. 1.

3 is a flowchart illustrating an operation process using a central control mode method in a path management method through encapsulation according to the present invention.

FIG. 4 is a diagram illustrating a delivery state of a packet by the flow of FIG. 3.

5 is a flowchart illustrating an operation process using a distributed control mode method in a path management method through encapsulation according to the present invention.

FIG. 6 is a diagram illustrating a delivery state of a packet by the flow of FIG. 5.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a path management method suitable for a centrally controlled multi-hop wireless network. More particularly, the present invention relates to a path management method through encapsulation in which a header containing information about a relay station is attached to a packet transmitted between a base station and a relay station. It is about how to manage.

In the central control wireless network, the control node that manages the entire network is the network for the central control. The control node is responsible for allocating radio resources and linking with the wired network. Multi-hop wireless network is a network in which the distance from the control node to the end terminal node is more than 1 hop, there may be a plurality of paths from the control node to the end terminal node.

Since the conventional centralized wireless network is generally designed based on a single hop, no special path management is performed. However, various path management methods have been studied in distributed wireless networks such as ad-hoc networks.

 When the node enters the network initially, the ad-hoc network broadcasts a control message and uses the response to obtain path information about the network. After that, when there is a periodic or network change, information is obtained from the network to maintain accurate path information.

The conventional central control wireless network has developed into a concept of replacing wires, and since only a single hop connection relationship between a control node and a terminal node is defined, path management itself is not required. However, in recent years, attempts have been made to extend single-hop wireless networks to multi-hop wireless networks. As a result, multipath problems in multi-hop have inevitably occurred. Various attempts have been made to solve this problem, and the most promising method was to use an algorithm studied in the existing ad-hoc network. However, since the ad-hoc network is designed to be suitable for a dynamic wireless network that is frequently changed, the ad-hoc network is not suitable for a static static wireless network. For example, the ad-hoc network defines a separate path management message for accurate path management, and frequently exchanges information with neighbor nodes using the defined message. These messages have a very large overhead in terms of network throughput, which degrades network performance. In addition, the ad-hoc network method is supported in the L3 layer, but the central control wireless network currently being standardized defines only L1 and L2, so there is a problem of exceeding the standard. Therefore, when the multi-hop network is extended using the ad-hoc network, modification of both the existing control node and the terminal node cannot be avoided.

The technical problem to be achieved by the present invention is to solve the above problems, the path management suitable for the central control multi-hop wireless network that can manage the path in a simple manner through the encapsulation of the packets transmitted and received between the base station and the relay station To provide a method.

In order to achieve the above technical problem, a recording medium recording a data structure of a packet header for path management using encapsulation in a multi-hop wireless network according to the present invention comprises a base station, a mobile terminal, and a relay station connecting the base station and the mobile terminal. A method for setting a path by a base station in a communication network, the method comprising: a mode field indicating a type of an operation mode for setting a path; An ID field containing ID information of the relay associated with the header generation; A hop field indicating the number of hops to the mobile terminal; And a length field indicating a length of a payload.

In order to achieve the above technical problem, the method for managing a path using encapsulation according to the present invention includes setting a path in a communication network including a base station, at least one mobile terminal, and at least one relay station connecting the base station and the mobile terminal. A method for adding a header by a relay station, the method comprising: determining whether the relay station is a final relay station communicating with the mobile terminal; If it is determined that the terminal station is the last relay station, adding a first header containing information including its ID and the length of the packet to a packet received from the mobile station and transmitting the packet to a higher node; If it is determined that the intermediate relay station is a second relay station, the first header added with the first header received by the lower relay station includes information including its ID, the ID of the lower relay station, the number of hops to the mobile station and the length of the packet. And adding two headers to transmit to a higher node.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. The present invention considers the wireless network as shown in FIG. FIG. 1 is a diagram illustrating an example of a configuration of a centrally controlled multi-hop wireless network to which the present invention is applied. FIG. 2 is a diagram of a tree structure in which the connection relationship of FIG. 1 is simplified. 3 is a flowchart illustrating an operation process by a central control mode method in a path management method through encapsulation according to the present invention, and FIG. 4 is a diagram illustrating a packet transmission by the flow of FIG. 3. Meanwhile, FIG. 5 is a flowchart illustrating an operation process using a distributed control mode method in a path management method through encapsulation according to the present invention, and FIG. 6 is a diagram illustrating a packet transmission by the flow of FIG. 5.

First, the terms are defined.

BS: Base Station. Base station.

MS: Mobile Station. Terminal station.

RS: Relay Station. Relay station.

Downlink: Area in which data is transmitted from BS to another UE.

Uplink: An area in which data is transmitted from another terminal to a BS.

Burst: A collection of logical data.

Node: A component of a network. In the present document, we refer to BS, RS and MS.

Hop: The logical distance between nodes. The distance from one node to a logically adjacent node is 1-hop.

Single hop: The distance between BS and last node is 1

Multihop: The distance is more than 2 because there is another node between BS and last node.

MAP: Information about the composition of the current frame.

A base station (hereinafter referred to as "BS (Base Station)" 101) is a control node of a central control wireless network, and a mobile terminal (hereinafter referred to as "MS (Mobile Station)", 105 to 109) is an end terminal node. (Hereinafter referred to as "RS", 102, 103, 104) is a newly added relay node for multi-hop support. At this time, since MS2 105 and MS4 106 are single-hop nodes, they communicate with BS 101 in the same manner as before. MS1 107 communicates with RS1 102, MS3 108 communicates with BS via RS1 102 or RS2 103, and MS5 109 communicates with RS2 103. Being a multi-hop node that communicates through RS3 104, the nodes to which the routing method according to the present invention is applied.

Let us look at the operation of a preferred embodiment according to the present invention.

The present invention provides a centralized path management mode and a distributed path management mode, and the header used includes information as shown in Table 1 below.

As a mode, a mode field indicating a type of operation mode for path setting indicates one of a centralized path management mode and a distributed path management mode. Next, the ID field is divided into two types. The first ID field (ID1 field) provides the ID information of the relay associated with the header generation, and the second ID field (ID2 field) is based on the type of the operation mode. Indicates one of the ID of the terminal. That is, in the central control mode, the ID of the immediately preceding node of the node generating the current header is indicated, and in the distributed control mode, the ID of the mobile terminal is indicated. The hop field indicates the number of hops to the mobile terminal, and the length field indicates the length of the payload.

It will be described how to manage the path for each of the two operation modes. First, the case of the central control mode will be described with reference to FIG. 3. In the case of the central control mode, all path management is performed by the BS, and the RS simply transfers headers to the packets. At this time, the BS creates and updates the reference table (Table 2 below) based on the information of the header of the RS (HRSx). In order to generate the header, it is first determined whether the relay station itself is the final relay station communicating with the mobile terminal (S310). The relay station may determine whether the lower node is a mobile terminal or another relay station from an ID field of information (for example, a header) received from the lower node.

As a result of the determination, if it is the last relay station, a first header containing information including its ID and the length of the packet is added to the packet received from the lower mobile station and transmitted to the upper node (step S320). If the determination result is that the relay station itself is an intermediate relay station, information including its ID, the ID of the lower relay station, the number of hops to the mobile station and the length of the packet is added to the packet to which the first header is received. In step S330, the second header is added to the upper node.

The detailed flow of steps S320 and S330 will be described with reference to FIG. 4. In FIG. 4, when the MS5 transmits the PMS5 packet 401 to the BS, the RS3 receiving the packet PMS5 has a header (HRS3) containing its information and the received packet (PMS5) as a payload. 402 is created and sent to RS2. RS2 again creates a packet 403 containing the header HRS2 containing its information and the received packet HRS3 + PMS5 as a payload and transmits it to the BS. After receiving the packet (HRS2 + HRS3 + PMS5), the BS separates the header of each RS (HRS2, HRS3) and the packet of the terminal, the header is used to generate a reference table (Table 2), the payload is a message to the MS Used for processing.

On the other hand, in the case of MS1, RS1 receives the packets PMS1 and 405 from MS1 as a case of the final relay station, and adds a header containing information including its ID and the length of the packet to the packet 406. ) And send it to BS.

In the case of MS4, there is no RS and a packet 407 without an RS header is directly transmitted to the BS.

By repeating this process, the reference table finally maintained in the BS will contain the contents shown in Table 2.

In the central control mode, the function of the BS is somewhat complicated, but the function of the RS can be simplified and all control can be centrally managed. In addition, since every packet has a header for extracting path information, it is suitable for use in a wireless network in which node movement is rather frequent.

The case of distributed control mode will now be described.

In the distributed control mode, the BS performs an overall path management function and the RS performs a path management function for an adjacent lower node. Therefore, both BS and RS maintain reference tables.

FIG. 5 is a flowchart illustrating an operation process using a distributed control mode method in a path management method through encapsulation according to the present invention, and FIG. 6 is a diagram illustrating a packet transmission by the flow of FIG. 5.

First, in order to generate a header, the RS determines whether it is the last RS which communicates with the MS (S510). As a result of the above determination, the final relay station adds a first header containing information including its ID and the length of the packet to the packet received from the mobile station and transmits it to a higher node, that is, another relay station. At this time, the mobile station generates and manages a first reference table (Table 3 below) having the ID, the upper node, and the hop number of the mobile terminal as elements (step S520).

However, when the determination results, the intermediate relay station performs a different operation from the central control mode. That is, the first header is deleted from the packet to which the first header (header containing the information of the lower relay station) received by the lower relay station is added, and the header including information of its ID and the length of the packet is first reproduced. The header forms a packet in addition to the payload. At this time, a second reference table (Table 4 below) is generated for each mobile terminal or relay station by using the ID, the type of the upper node of the mobile terminal or the relay station, and the number of hops as elements.

In FIG. 6, when MS5 transmits a PMS5 packet 601 to a BS, RS3 receiving the packet PMS5 adds information about MS5 to its reference table, and then includes a header (HRS3) containing its information. And a packet 602 having the received packet PMS5 as a payload, and then transmitted to RS2. After receiving the packet (HRS3 + PMS5, 602), RS2 adds information about RS3 and MS5 to its reference table, and then sends the packet to the header (HRS5) containing the information and the payload (PMS5) of the received packet. 603 is created and sent to the BS. Finally, upon receiving the packet (HRS2 + PMS5), the BS adds information about RS2 and MS5 to its reference table. When this process is performed in the BS and all RSs, a reference table as shown in Tables 3 to 6 is generated. At this time, if there is no packet generated by the RS itself and transmitted to the BS, the shaded part of Table 3 is not generated.

On the other hand, in the case of MS1, RS1 receives packets PMS1 and 605 from MS1 as corresponding to the last relay station, and adds a header containing information including its ID and packet length to packet 607. ) And send it to BS.

In the case of MS4, there is no RS, and a packet 608 without an RS related header is directly transmitted to the BS.

The distributed control mode adds some complexity to the RS because it distributes all the controls, but reduces the load that has been concentrated on the BS. In addition, since the header includes only the information about the adjacent node and the last node, the header alone cannot obtain the information about the intermediate path. Therefore, the distributed control mode is a mode suitable for a static wireless network, and a forwarded packet includes only a header having a constant size regardless of the number of hops.

 Comparing the BS reference table in the distributed control mode and the central control mode, a difference occurs in the information of the terminal such as MS5. In the central control mode, it is necessary to manage the path information to all intermediate nodes because it is central management. However, since the distributed control mode is distributed, only the path information to the adjacent node and the lowest node need to be managed.

In addition, a packet transmitted from the BS to the MS uses an inverse encapsulation method of removing an additional header.

The functions used in the path management method using encapsulation in the multi-hop wireless network disclosed herein may be implemented as computer readable codes on a computer readable recording medium. The computer-readable recording medium includes all kinds of recording devices in which data that can be read by a computer system is stored. Examples of computer-readable recording media include ROM, RAM, CD-ROM, magnetic tape, floppy disks, optical data storage devices, and the like, which may also be implemented in the form of carrier waves (for example, transmission over the Internet). do. The computer readable recording medium can also be distributed over network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion. And functional programs, codes and code segments for implementing the present invention can be easily inferred by programmers in the art to which the present invention belongs.

As described above, optimal embodiments have been disclosed in the drawings and the specification. Although specific terms have been used herein, they are used only for the purpose of describing the present invention and are not intended to limit the scope of the present invention as defined in the claims or the claims. Therefore, those skilled in the art will understand that various modifications and equivalent other embodiments are possible from this. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

As described above, the path management method using encapsulation in the multi-hop wireless network according to the present invention does not require modification of the terminal and is easy to implement because it is a simple method through packet encapsulation. In addition, the resource usage is less than that of the conventional ad-hoc method, thereby improving network performance.

Claims (8)

In the path management method using encapsulation in a multi-hop wireless network consisting of a base station, a mobile terminal, and a relay station connecting the base station and the mobile terminal, (a) determining whether the relay station is the last relay station communicating with the mobile terminal; (b) if it is the final relay station, adding a first header containing information including its ID and the length of the packet to a packet received from the mobile station and transmitting the same to the higher node; (c) If the determination results in the intermediate relay station, information including its ID, the ID of the lower relay station, the number of hops to the mobile station, and the length of the packet is included in the packet to which the first header received by the lower relay station is added. And adding a second header to the upper node and transmitting the same to a higher node. The path management method using encapsulation in a multi-hop wireless network, comprising: a second header; The method of claim 1, wherein step (a) If the relay station is a single-hop relay station directly connecting the mobile station and the base station, the path management method using encapsulation in a multi-hop wireless network, characterized in that for transmitting as it is a packet transmitted by the mobile station. The method of claim 1, And separating, by the base station, the first header and the second header from the packet and constructing a reference table for path setting based on the headers. How to manage your route. The method of claim 3, wherein the reference table is In the multi-hop wireless network, the path management method using the encapsulation, characterized in that each element of the mobile station or relay station, the type and hop number of the upper node of the mobile station or relay station. In the path management method using encapsulation in a multi-hop wireless network consisting of a base station, a mobile terminal, and a relay station connecting the base station and the mobile terminal, (a) determining whether the relay station is the last relay station communicating with the mobile terminal; (b) if it is the final relay station, adding a first header containing information including its ID and the length of the packet to a packet received from the mobile station and transmitting the same to the higher node; And (c) If the determination results in the intermediate relay station, the first header is deleted from the packet to which the first header received by the lower relay station is added, and a header including information of its ID and the length of the packet is returned to the first header. Adding a; path management method using encapsulation in a multi-hop wireless network comprising a. The method of claim 5, wherein step (b) (b1) adding a first header containing information including its ID and the length of the packet to a packet transmitted by the mobile station and transmitting the first header to the base station; And (b2) generating a first reference table including IDs, upper nodes, and hop counts of the mobile terminal as elements; and a path management method using encapsulation in a multi-hop wireless network. The method of claim 5, wherein step (c) Generating a second reference table for each ID of the mobile terminal or relay station, the type of the upper node of the mobile terminal or relay station, and the number of hops with each element; a path using encapsulation in a multi-hop wireless network, comprising: How to manage. The method of claim 5, And separating, by the base station, the first header from the packet and constructing a reference table for setting a path based on the headers thereof.

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