KR101503464B1 - Multi-Channel Scheduling Method for Collision Free High Rate Wireless Personal Area Network - Google Patents

Abstract

The present invention relates to a multi-channel scheduling method for collision avoidance in a high-speed wireless personal communication network, and a multi-channel scheduling method for collision avoidance in a high-speed wireless personal communication network according to the present invention can be performed in a wireless communication environment in which a plurality of WSS networks coexist. In order to solve the data collision effectively, a new idle channel is searched to newly transmit a beacon frame and a data frame. According to the present invention, it is possible to maximize the usability of an available radio channel by performing an effective channel scan during a valid period to provide information on an actual radio environment. In addition, after the data collision occurs, the channel can be quickly moved to the effective channel by scanning the effective channel in the normal time, and the network disconnection due to the data collision can be minimized.

Description

TECHNICAL FIELD [0001] The present invention relates to a multi-channel scheduling method for collision avoidance in a high-speed wireless personal communication network,

The present invention relates to a multi-channel scheduling method for collision avoidance in a high-speed wireless personal communication network, and more particularly, to a method for managing multiple channels in order to avoid collision between adjacent networks.

UWB-based WiMedia and wireless USB networks can coexist in the same wireless environment depending on the application, and there may be a case where communication between these networks is necessary, and a case where communication between networks existing in a remote place is necessary.

For this purpose, the WiMedia Alliance has defined the frame format and requirements for transmitting network layer packets over the WiMedia radio platform as the WiMedia logical link protocol (WLP) standard.

This specification defines support for interfacing frames between WLP and Ethernet protocols, or other similar network protocols, as well as security settings between devices.

Client devices can communicate directly with other client devices belonging to the same WSS (WLP Service Set) and can communicate with nodes, such as client devices, Ethernet stations, belonging to other WSSs, using services provided by the client bridge have.

A client bridge having a client bridge function forwards a frame to client devices having requested bridge services.

Here, the client device may be the final destination device of the data transmitted in the WLP frame, or may be the device that sent the original data, and may be directly connected to the client bridge to communicate with devices having a destination address that can be delivered via the client bridge Frame.

Client bridges and client devices must belong to the same WSS so that the client bridges can provide relay services.

Remote bridges provide connectivity between network segments. Remote bridges can exchange frames with other remote bridges, so that each remote bridge pair creates a new segment for relaying network segments belonging to remote bridges.

Remote bridges implement IEEE 802.1D to perform relaying mechanism, determine destinations to transmit frames using filter table, and implement spanning tree protocol to eliminate redundant paths that may occur throughout the network Respectively.

The client device, the client bridge, and the network including the remote bridge are as shown in FIG.

On the other hand, UWB-based networks are mixed in a small wireless environment such as a home or an office.

Since these networks operate independently for each application, each network may cause data collision with an adjacent network.

Therefore, although each network can use resources of different time zones to avoid data collision with neighboring networks, even if resources of different time zones are used, if there are many devices in the network, available resources are reduced, If there is a shortage of required resources and this lack of resources is needed, there can be various types of data conflicts.

However, the WiMedia, WUSB, and WLP standards are built without taking into consideration the case where data collision occurs due to a shortage of necessary resources. Therefore, there is a problem that data collision can not be prevented when the situation is encountered.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is an object of the present invention to search for a new idle channel and transmit a new beacon frame and a data frame in order to efficiently resolve data conflicts that may occur in a wireless communication environment in which a plurality of WSS networks coexist And to provide a multi-channel scheduling method for collision avoidance in a high-speed wireless personal communication network.

In order to achieve the above object, in an environment where a plurality of wireless personal area networks (WPANs) according to one aspect of the present invention coexist adjacent to a specific area and operate simultaneously, (WPAN) is a WiMedia logical link protocol service set (WLP). When a specific bridge device selects a WSS ID, which is unique information of a specific WSS to be generated, and an idle channel, Performing a scan to generate the specific WSS; Setting a generated WSS ID, which is unique information of the specific WSS, and broadcasting the generated WLP IE including information on the generated WSS in a beacon; Configuring the specific WSS by joining the specific device to the specific WSS when an association frame for subscription is received from a specific device receiving the broadcasted beacon; Scanning the other available radio channel (idle channel) during an inactive period of the particular bridging device; And if the beacon frame collision is detected by the specific device, forming a network again with a device belonging to the specific WSS in the idle channel scanned by the bridge device, Defining a DRP (Distributed Reservation Protocol) section reserved by other devices in the WiMedia data transmission period as the inactive section; And scanning the idle channel in the defined inactive section.

According to the present invention, in order to efficiently resolve data collisions that can occur in a wireless communication environment in which a plurality of WSS networks coexist, effective channel scanning is performed during a valid period to provide information on an actual radio environment, Thereby maximizing usability.

In addition, after the data collision occurs, the channel can be quickly moved to the effective channel by scanning the effective channel in the normal time, and the network disconnection due to the data collision can be minimized.

1 illustrates a network environment in which a plurality of WSSs exist.
2 is a diagram for explaining a WSS network topology;
3 is a diagram for explaining the structure of a WLP IE;
4 is a view for explaining a WSS formation process;
5 is a diagram for explaining an idle channel scanning process;
6 is a diagram for explaining a structure of a WSS Collision IE;
7 is a diagram for explaining a structure of a Channel Change IE;

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention and the manner of achieving them will become apparent with reference to the embodiments described in detail below with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. And is intended to enable a person skilled in the art to readily understand the scope of the invention, and the invention is defined by the claims. It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. It is noted that " comprises, " or "comprising," as used herein, means the presence or absence of one or more other components, steps, operations, and / Do not exclude the addition.

Hereinafter, a multi-channel scheduling method for collision avoidance in a high-speed wireless personal area network according to an embodiment of the present invention will be described with reference to FIG. 1 to FIG. 2 is a view for explaining a WSS network topology, FIG. 3 is a view for explaining a structure of a WLP IE, and FIG. 4 is a diagram illustrating a WSS formation FIG. 5 is a view for explaining an idle channel scanning process, FIG. 6 is a view for explaining a structure of a WSS Collision IE, FIG. 7 is a view for explaining a structure of a Channel Change IE to be.

In the present invention, a plurality of WPANs (Wireless Personal Area Networks) coexist adjacent to a specific area, operate simultaneously, use a WiMedia PHY, and operate independently for each application.

For example, UWB-based WiMAX and wireless USB networks can coexist in the same wireless environment depending on applications, and in such a coexisting situation, communication may be required between these networks.

To this end, WiMedia Alliance has defined a frame format and requirements as a communication protocol in order to transmit packets in the network layer on the WiMedia radio platform. The defined communication protocol is WiMedia logical link protocol (WLP) WSS (WLP Service Set).

The wireless environment in which a plurality of WSSs exist is as shown in FIG.

B1, B2 and B3 are bridge devices (bridge devices) of WSS1, WSS2 and WSS3, D1 is a device belonging to WSS1 and WSS2, D2 is a device belonging to WSS1, WSS2 and WSS3, Channel X is used, and WSS3 uses another wireless channel Y. [

When the device D1 detects a data frame collision and transmits a WSS Collision IE to the bridge device B1 of the WSS 1 to which the WSS 1 belongs, the bridge device B1 receiving the WSS Collision IE transmits the idle channel in the inactive interval Search.

When the bridge device B1 receives data from the device D2 located in the area where WSS1, WSS2 and WSS3 overlap, it determines that the wireless channel Y is also in use and scans another wireless channel z.

If it is determined that there is no WSS using the scanned wireless channel z, the bridge device B1 sets the new channel number field of the Channel Change IE to the wireless channel z, and then broadcasts a Channel Change IE to devices belonging to its WSS1 Cast.

2, each of the WPANs 100, 200, and 300 is a WSS (WLP Service Set). In order to communicate with an external network, one bridge device 110, 210 and 310, respectively.

Each bridge device 110, 210, 310 communicates with the outside using Ethernet (Ethernet).

When the WSS uses the WUSB protocol, the WUSB host also acts as a client bridge.

That is, each of the WSSs 100, 200, and 300 uses a WiMedia (WiMedia) protocol and includes each of the bridge devices 110, 210, and 310 connected to the outside and the Ethernet, Device, and each bridge device 110, 210, 310 initializes and configures each WSS 100, 200, 300.

For example, the bridge device 110 performs a scan to select an idle channel and a WSS ID, which is unique information for indicating a WSS 100 to be generated before the new WSS 100 is initially created.

After that, the bridge device 110 that created the WSS 100 sets a unique WSS ID for indicating the WSS 100 of itself and sets the WLP IE containing the information about the WSS 100 created by the bridge device 110 as its own Broadcast it in beacon.

The structure of the WLP IE is as shown in FIG.

In the WLP technical specification, the bridge device 110 that created the WSS 100 is referred to as a registar, and the device 120 that subscribes to the WSS 100 is expressed as enrollee, and this definition is also used in the present invention.

The sequence of registar and enrollee constructing the WSS is shown in FIG.

The enrollee 120 transmits an association frame to the registar 110 in order to join the WSS 100 when the beacon broadcast by the registrar 110 is received.

The enrollee 120 uses the Imm-ACK policy when transmitting the association frame to the registar 110. [ That is, if the enrollee 120 fails to receive the Imm-ACK frame, the enrollee 120 retransmits the association frame to the registar 110.

Meanwhile, when the bridge device 110 scans another available radio channel during an inactive period and a beacon frame collision is recognized by the specific device 130, the bridge device 110 transmits the corresponding devices belonging to the WSS 100 in the scanned idle channel, Lt; RTI ID = 0.0 > 120, < / RTI >

The bridging device 110 checks whether another device 120 belonging to the WSS 200 is using the remaining wireless channel (idle channel), and transmits data received from another device 120 during the scan period Frame to indirectly recognize the presence of another WSS 200. [

WiMedia and WUSB standards, which are the networks that make up the WSS, do not define separate inactive intervals in the superframe. Therefore, the present invention defines WiMedia and WUSB as intervals for scanning an idle channel.

The data transmission interval of WiMedia is largely classified into a PCA (Prioritized Contention Access) interval and a DRP (Distributed Reservation Protocol) interval.

The bridge device 110 can not move to another wireless channel in order to retrieve the idle channel in the PCA section because the PCA section is in a contention period and therefore it is not known when data will be received.

Since the DRP interval is reserved for specific devices to exchange data without contention, the bridge device 110 can not receive data unless it is a reserved interval in the DRP interval.

Therefore, the bridge device 110 defines the DRP interval reserved by other devices as the inactive interval, and performs the idle channel scanning in the corresponding interval.

In the case of the WUSB network, since only a specific data transmission interval is used in the super frame of the WiMedia MAC, the WUSB host defines the remaining interval excluding the interval used by the WUSB cluster as the inactive interval, and performs idle channel scanning .

The scanning mechanism of the MCS is as shown in FIG.

When a data collision is detected, the device 130 notifies the bridge device 110 of the WSS 100 to which it belongs, of the occurrence of the collision.

For example, the device 130 informs the bridge device 110 of a data collision with the WSS Collision IE, as shown in FIG.

The device 130 that detects the collision displays the collision period in the Collision Period Bitmap field, and then transmits the beacon frame to the bridge device 110.

The bridge device 110 receiving the WSS Collision IE selects one of the idle channels and informs the devices 120 and 130 in the WSS 100 of a channel to be moved.

The bridge device 110 broadcasts the channel change IE included in its beacon to the members 120 and 130 of the WSS 100, as shown in FIG. 7, in order to provide information on the channel movement.

The bridge device 110 stores the information of the channel to be moved in the New Channel Number field and stores it in the Channel Change Countdown field of the superframe to be moved to notify the members 120 and 130 of the WSS 100.

The members 120 and 130 of the WSS 100 receiving the Channel Change IE move to the designated channel in the designated superframe period to continue the existing communication.

As described above, according to the present invention, data conflicts that may occur in a network environment in which a plurality of WSSs coexist can be solved.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. Therefore, the scope of the present invention should not be limited by the illustrated embodiments, but should be determined by the scope of the appended claims and equivalents thereof.

100, 200, 300: WSS
110, 210, 310: Bridge device
120, 130: Device

Claims (2)

A multi-channel scheduling method for collision avoidance in each high-speed wireless personal communication network in an environment in which a plurality of wireless personal area networks (WPANs) coexist adjacent to a specific area and operate simultaneously,
Each wireless personal area network (WPAN) is a WiMedia logical link protocol service set (WSS)
Generating a specific WSS after a specific bridge device performs a scan to select an idle channel and a WSS ID that is unique information of a specific WSS to be generated by the specific bridge device;
Setting a generated WSS ID, which is unique information of the specific WSS, and broadcasting the generated WLP IE including information on the generated WSS in a beacon;
Configuring the specific WSS by joining the specific device to the specific WSS when an association frame for subscription is received from a specific device receiving the broadcasted beacon;
Scanning the other available radio channel (idle channel) during an inactive period of the particular bridging device; And
When the beacon frame collision is recognized by the specific device, forming a network again with a device belonging to the specific WSS in the idle channel scanned by the bridge device,
Wherein the step of scanning comprises:
Defining a DRP (Distributed Reservation Protocol) section in which the specific bridge device is reserved by other devices in the WiMedia data transmission period as the inactive section; And
And scanning the idle channel in the defined inactive period.
A multi - channel scheduling method for collision avoidance in a high - speed wireless personal communication network. 2. The method of claim 1, wherein the forming the network further comprises:
Transmitting a new WSS Collision IE to inform the specific bridge device of the collision of the specific device that detected the collision;
Selecting one of the idle channels scanned by the bridge device that has received the WSS Collision IE; And
And broadcasting a channel change IE included in the beacon to broadcast the selected idle channel to the devices in the specific WSS.
A multi - channel scheduling method for collision avoidance in a high - speed wireless personal communication network.

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