JPH10164073A - Radio lan system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To set communication with a radio terminal equipment in the other cell or a wire terminal equipment connected to a wire transmission line to be efficient by permitting a control terminal equipment to give the response of reception success or failure on a frame to the outer part of a cell. SOLUTION: At the time of executing communication from the radio terminal equipment 2a to the wire terminal equipment 5 through an access pointer 3, a transmission/reception control part stores a user frame in a buffer by adding a sequence number, sets the media access control MAC addresses of the wire terminal equipment 5 and the self-device and transmits the frame from the buffer to a radio transmission line 10. An access point 3 temporarily stores the reception frame and abolishes it when the reception of the frame is failed. The response ACK is returned to the terminal equipment 2a, the frame is converted into a wire format when reception succeeds. A repeating processing is executed as soon as the transmission line 4 becomes idle. When the terminal equipment 2a receives ACK, it counts up the sequence number and transmits the next frame.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless LAN system comprising a plurality of wireless terminals, and more particularly, to a wireless terminal connected to a wireless terminal in another cell or a wired transmission line via a control terminal. M when communicating with the terminal device
The present invention relates to a technology that is effective when applied to a wireless LAN system that retransmits an AC (Media Access Control) frame.

[0002]

2. Description of the Related Art As a known wireless LAN system, for example, there is a system adopting a centralized control system in which one control terminal device controls data transmission and realizes 1: N communication, and is connected to a wired transmission line. In this case, the access point is used as a control terminal device.

The access control method is TDMA (T
im Division Multiple Acc
ess).

A conventional wireless LAN adopting the centralized control system described above
In the AN system, since one control terminal device performs access control of the entire wireless LAN system, MA control is relatively easy.
C layer retransmission control can be realized.

On the other hand, the centralized control system includes:
CSMA / CA (Carr) has disadvantages such as (1) a control terminal device is always required in the wireless LAN system, and (2) communication becomes impossible if a failure occurs in the control terminal device.
er Sense Multiple Access
with Collision Avidanc
e) and the like, and a peer-to-peer distribution method is realized in which N: N communication is realized by making each wireless terminal device mutually communicate with the same transmission right.

[0006]

In the conventional wireless LAN system adopting the centralized control method, MAC layer retransmission control in which MAC layer retransmission is realized by an access point as a control terminal device is performed by one control terminal device.
To control layer retransmission, wireless L adopts a peer-to-peer distribution method.
There was a problem that it could not be used with the AN system.

In addition, the conventional wireless LA of the peer-to-peer distribution method
In the N system, a wireless LA not including an access point
Although there is a system in which the MAC layer retransmission is realized in the N system, none of the wireless LAN systems including the access point realize the MAC layer retransmission.

An object of the present invention is to provide a technology capable of efficiently performing communication with a wireless terminal device in another cell or a wired terminal device connected to a wired transmission line.

Another object of the present invention is to provide a technique capable of preventing duplicate reception of frames.

Another object of the present invention is to provide a technique capable of managing sequence information in a processing procedure with a low processing load.

It is another object of the present invention to provide a technique capable of performing sequence management for increasing the prevention rate of receiving duplicate frames.

The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

[0013]

SUMMARY OF THE INVENTION Among the inventions disclosed by the present application, the outline of a representative one will be briefly described.
It is as follows.

(1) In a wireless LAN system connected to another cell or a wired transmission line via a control terminal device, a frame is transmitted to a wireless terminal device outside the cell or a wired terminal device connected to the wired transmission line. The retransmission control is performed by a control terminal device that connects the wired transmission path and the cell.

In the wireless LAN system, first, MAC addresses of a plurality of wireless terminal devices existing in the same cell are stored in a filtering database.

When the control terminal device of the wireless LAN system receives the frame, the transmission / reception control unit checks whether or not the destination address of the received frame matches the MAC address stored in the filtering database.

If the destination address of the received frame is in the filtering database, the transmission / reception control unit suppresses transmission of a response indicating success or failure of reception.

If the destination address of the received frame is not in the filtering database, the transmission / reception control unit returns a response indicating reception success or reception failure.

On the other hand, the transmission / reception control unit of the wireless LAN system may determine that the destination address of the received frame is in the filtering database, or that the destination address of the received frame is not in the filtering database and the frame has an error. In some cases, the frame is discarded.

If the destination address of the received frame is not in the filtering database and there is no error in the frame, the receiving process of the frame is performed.

As described above, in the wireless LAN system, since the control terminal device receives a frame and transmits a response to the outside of the cell, communication is performed in the cell by the peer-to-peer distribution method and other cells are communicated. Communication with a wireless terminal device or a wired terminal device connected to a wired transmission path.

Further, in the wireless LAN system, communication is performed in the cell by the peer-to-peer distribution method, so that communication in the cell can be continued even if the control terminal device fails. .

As described above, according to the wireless LAN system, since the control terminal device receives a frame to the outside of the cell and responds to the success or failure of the reception, the wireless terminal device in another cell or Communication with a wired terminal device connected to a wired transmission path can be performed efficiently.

(2) Wireless LAN described in (1) above
In the system, in the wireless LAN system,
The sequence of received frames is recorded, and the received frames are discarded by the control terminal device.

When a frame is received in the wireless LAN system, it is checked whether the source address and sequence number of the received frame are registered in the sequence management table, and the sequence of the received frame is registered in the sequence management table. If so, the frame is discarded.

If the source address and sequence number of the received frame are not registered in the sequence management table, the source address and sequence number of the received frame are registered in the sequence management table.

As described above, according to the wireless LAN system, since the frames of the sequence registered in the sequence management table are discarded, it is possible to prevent duplicate reception of the frames.

(3) The wireless LAN described in the above (2)
In the system, in the wireless LAN system,
The source address and the sequence number of the received frame are registered to manage the received frame.

When a frame is received in the wireless LAN system, if there is a space in the sequence management table, the source address and sequence number in the received frame are registered in the order of arrival of the received frame without overwriting the sequence management table. .

If there is no free space in the sequence management table, the source address and sequence number registered at the oldest time in the sequence management table are deleted, and the source address and sequence number in the received frame are registered. I do.

As described above, according to the wireless LAN system, the source address and the sequence number of the received frame are registered in the order of arrival, so that the sequence information can be managed in a processing procedure with a low processing load. .

(4) Wireless LAN described in (2) above
In the system, in the wireless LAN system,
The latest sequence number corresponding to the source address of the received frame is registered to manage the received frame.

When a frame is received in the wireless LAN system, if the source address in the received frame is already registered in the sequence management table, only the sequence number in the received frame is stored in the sequence management table. Register at the position corresponding to.

If the source address in the received frame is not registered in the sequence management table and there is a space in the sequence management table, the source address and sequence number in the received frame are registered in the sequence management table. I do.

Further, when the source address in the received frame is not registered in the sequence management table and there is no space in the sequence management table, the source address registered at the oldest time in the sequence management table is The sequence number is deleted, and the source address and the sequence number in the received frame are registered in the sequence management table.

In the above-described wireless LAN system, when the transmission source address and the sequence number of the received frame are registered in the order of arrival, the registration of the sequence information can be performed by a processing procedure with a relatively low processing load.

However, there is a high possibility that the sequence information of the registered received frame is overwritten by the sequence information of another received frame. If the overwritten sequence information frame is transmitted again, the received frame information is redundantly received. Processing is performed.

If the sequence information of the received frame is overwritten and registered in the item corresponding to the source address, the latest sequence information for each source address remains in the sequence management table. ,
The possibility that sequence information of a specific received frame is overwritten by other sequence information is reduced, and the prevention rate of reception of duplicate frames can be increased.

As described above, according to the wireless LAN system, the sequence information of the received frame is overwritten and registered in the item corresponding to the source address, so that the sequence management for improving the prevention rate of receiving the duplicated frame is performed. It is possible to do.

[0040]

BEST MODE FOR CARRYING OUT THE INVENTION In the wireless LAN system of the present invention, communication with a wireless terminal device in another cell or a wired terminal device connected to a wired transmission line via an access point as a control terminal device will be described below. A wireless LAN system according to an embodiment for performing the above will be described.

FIG. 1 is a diagram showing a schematic configuration of a wireless LAN system according to the present embodiment. In FIG. 1, 1 is a cell,
2a and 2b are wireless terminal devices, 3 is an access point,
4 is a wired transmission path, 5 is a wired terminal device, and 10 is a wireless transmission path.

As shown in FIG. 1, the wireless LAN of this embodiment
The system comprises a cell 1, wireless terminals 2a and 2b,
It has an access point 3, a wired transmission path 4, a wired terminal device 5, and a wireless transmission path 10.

As shown in FIG. 1, in the wireless LAN system according to the present embodiment, the wireless terminal devices 2a and 2b and the access point 3 exist in the cell 1 showing the same frequency range, and the cell 1 Is connected to the wired transmission line 4 in which the wired terminal device 5 exists.

In the wireless LAN system of the present embodiment, the wireless terminal devices 2a and 2b and the access point 3 in the cell 1 use a low-frequency hopping spread spectrum system in which the carrier frequency is changed at a constant period longer than the symbol period. To communicate with each other.

That is, in the cell 1, the used carrier frequency is periodically changed.
In the N system, the hopping cycle is set to 100 ms and the number of hops is set to 13 for explanation.

FIG. 2 is a diagram showing an outline of carrier frequency allocation in the wireless LAN system of the present embodiment. In FIG. 2, 6 is an ISM band, and 7a to 7m are subchannels.

As shown in FIG. 2, the wireless LAN of this embodiment
The system carrier frequency allocation is in ISM band 6
And sub-channels 7a to 7m.

As shown in FIG. 2, in the assignment of carrier frequencies in the wireless LAN system of the present embodiment, 2471 to 249 assigned for the spread spectrum method are used.
The ISM band 6 having a bandwidth of 7 MHz and a bandwidth of 26 MHz is used.

In the wireless LAN system of this embodiment, this ISM band 6 is divided into 13 subchannels 7a to 7m each having a width of 2 MHz, and therefore, the center frequency of each carrier frequency of subchannels 7a to 7m is divided. Is fi = 2
472 + 2i (i = 0,..., 12) MHz.

FIG. 3 is a diagram showing an outline of a hopping pattern and a hopping cycle of the wireless LAN system of the present embodiment. In FIG. 3, 8 is a hopping cycle, 81 is a user frame area RU, 82 is a non-transmission area RN, 83
Denotes a control frame area RC, and 84 denotes a dummy area RD.

As shown in FIG. 3, the wireless LAN of this embodiment
The hopping pattern and hopping cycle of the system are:
User frame area RU81 and non-transmission area RN82
, A control frame area RC83, and a dummy area RD84.
And

As shown in FIG. 3, in the hopping pattern and the hopping period of the wireless LAN system of the present embodiment, “f0”, which is an example of the hopping pattern,
"F6", "f12", "f5", "f11", "f
4 "," f10 "," f3 "," f9 "," f2 ",
Each sub-channel is hopped according to a repetition pattern of “f8”, “f1”, and “f7”.

In the wireless LAN system according to the present embodiment, one hopping cycle 8 is 100 ms, and the area of one hopping cycle 8 is the user frame area RU.
81, non-transmission area RN82, control frame area RC83
And a dummy region RD84.

In the user frame area RU81 of the hopping cycle 8 in the wireless LAN system of this embodiment, user data is transmitted and received using a user frame.

Non-transmission area RN82 with hopping period 8
Is an area provided to avoid collision between a user frame transmitted in the user frame area RU81 and a control frame transmitted in the next control frame area RC83,
A new user frame cannot be transmitted between the non-transmission areas RN82.

Control frame area RC with hopping period 8
83 is an area for transmitting a control frame, for example,
This is an area for transmitting a control frame (hereinafter, referred to as an FH-MAC frame) carrying information necessary for hopping control.

In the wireless LAN system of the present embodiment, hopping is controlled only by the access point 3 existing in the cell 1, and the FH is controlled at 100 ms intervals.
Sending a MAC frame;

Dummy area RD84 with hopping cycle 8
Is an area for securing the time required for synthesizer switching, and the switching operation of the carrier frequency is performed during this area.

FIG. 4 is a diagram showing an outline of a frame format used on the wireless transmission path 10 of the wireless LAN system according to the present embodiment. In FIG. 4, 9 is a frame format, 91 is an area P, 92 is an area F, and 93 is an area F
C and 94 are areas DA, 95 is area SA, 96 is area I,
Reference numeral 97 denotes an area FCS.

As shown in FIG. 4, the wireless LAN of this embodiment
The frame formats used on the wireless transmission path 10 of the system include an area P91, an area F92, and an area FC93.
Area DA94, area SA95, area I96,
And an area FCS97.

As shown in FIG. 4, in the frame format used on the wireless transmission path 10 of the wireless LAN system according to the present embodiment, the area P91 is provided to the physical layer for establishing and maintaining synchronization in the physical layer. A region F92 is arranged following the region P91, and represents a substantial head of effective information in the present frame.

Area FC93 of frame format 9
Is a frame control area, which is an area for storing identification information and a sequence number of a user frame and a control frame.

For example, when the access point 3 notifies hopping information to the wireless terminal devices 2a and 2b in the cell 1, a sequence number is set in this area FC93 and bits indicating the control frame of the area FC93 are set. Enable and communicate.

Area DA94 of frame format 9
Is an area for storing a destination address, and is an area SA9
An area 5 stores a source address, and an area I9
Reference numeral 6 denotes an information section.

Area FCS97 of frame format 9
Is a frame check sequence, and uses a CRC code as an error detection code to detect an error in a frame excluding the region P91 and the region F92, and, when there is an error in the frame, an area used for notifying as an FCS error. It is.

FIG. 5 is a diagram showing a schematic configuration of the wireless terminal devices 2a and 2b of the wireless LAN system of the present embodiment. 5, reference numeral 201 denotes an antenna, 202 denotes a wireless modulation / demodulation unit, 203 denotes a transmission / reception control unit, 204 denotes a sequence management table, 205 denotes a wireless reception buffer, 206 denotes a wireless transmission buffer, 207 denotes a system bus, 208 denotes a personal computer, and 209 denotes a personal computer. It is a local bus.

As shown in FIG. 5, the wireless LAN of this embodiment
The wireless terminals 2a and 2b of the system
1, a wireless modulation / demodulation unit 202, a transmission / reception control unit 203,
Sequence management table 204 and wireless reception buffer 2
05, the wireless transmission buffer 206, and the system bus 20
7, a personal computer 208, and a local bus 209.

As shown in FIG. 5, in the wireless terminal devices 2a and 2b of the wireless LAN system according to the present embodiment, the antenna 201, the wireless modulation / demodulation unit 202, the transmission / reception control unit 20
3. The sequence management table 204, the wireless reception buffer 205, and the wireless transmission buffer 206
9 and to a personal computer 208 via a system bus 207.

The wireless modulation / demodulation unit 202 of the wireless terminal devices 2 a and 2 b of the wireless LAN system according to the present embodiment performs a modulation process and a frequency conversion process to the 2.4 GHz band on the frame transmitted from the transmission / reception control unit 203. A processing unit for performing the transmission from the antenna 201.

The radio modulation / demodulation units 202 of the radio terminal devices 2a and 2b perform a frequency conversion process to a baseband and a demodulation process on the frame received from the antenna 201, and transmit the frame to the transmission / reception control unit 203. Do.

The transmission / reception control unit 203 of each of the wireless terminal devices 2a and 2b is a control unit that performs transmission / reception control such as hopping instruction and frame identification.

The sequence management table 204 of the wireless terminal devices 2a and 2b is a table for storing a source address and a sequence number of a frame received by the wireless terminal device 2a or 2b, and managing received frames.

The wireless reception buffer 205 of each of the wireless terminal devices 2a and 2b is a buffer for storing a frame received by the wireless transmission path 10, and the wireless transmission buffer 206
Is a buffer for storing a frame transmitted by the wireless transmission path 10.

FIG. 6 is a diagram showing a schematic configuration of the access point 3 of the wireless LAN system of the present embodiment. FIG.
, 301 is an antenna, 302 is a wireless modulation / demodulation unit,
303 is a transmission / reception control unit, 304 is a sequence management table, 305 is a wireless reception buffer, 306 is a wireless transmission buffer, 307 is a wired reception buffer, 308 is a wired transmission buffer, 309 is a wired control unit, and 310 is a filtering database (hereinafter referred to as FDB). 311 is a relay control unit, 312 is a local bus, and 313 is an aging timer.

As shown in FIG. 6, the wireless LAN of this embodiment
The access point 3 of the system includes an antenna 301,
Radio modulation / demodulation section 302, transmission / reception control section 303, sequence management table 304, radio reception buffer 305
, The wireless transmission buffer 306 and the wired reception buffer 30
7, a wired transmission buffer 308, and a wired control unit 309.
, An FDB 310, a relay control unit 311, a local bus 312, and an aging timer 313.

As shown in FIG. 6, in the access point 3 of the wireless LAN system according to the present embodiment, the antenna 3
01, a wireless modulation / demodulation unit 302, a transmission / reception control unit 303, a sequence management table 304, a wireless reception buffer 305,
Wireless transmission buffer 306, wired reception buffer 307, wired transmission buffer 308, wired control unit 309, FDB31
0, the relay control unit 311 and the aging timer 313 are connected by the local bus 312 and
It is connected to the.

The wireless modem 302 of the access point 3 of the wireless LAN system of the present embodiment
The modulation process and the frequency conversion process to the 2.4 GHz band are performed on the frame transmitted from
It is a processing unit that transmits from “01”.

Further, the radio modulation / demodulation unit 302 of the access point 3 performs a process of converting the frequency of the frame received from the antenna 301 into a base band and a process of demodulating the frame and transmitting the frame to the transmission / reception control unit 303.

Transmission / reception controller 303 of access point 3
Is a control unit that performs transmission / reception control such as a hopping instruction and frame identification. When the transmission destination address of the received frame is within the FDB 310, it does not return a response indicating reception success or reception failure, When the destination address is not in the FDB 310, the control unit returns a response indicating success or failure of reception.

The transmission / reception control unit 303 determines whether the destination address of the received frame is in the FDB 310 or the destination address of the received frame is the FDB 31
If it is not 0 and there is an error in the frame, the frame is discarded. If the destination address of the received frame is not in the FDB 310 and there is no error in the frame, reception processing is performed.

The sequence management table 304 of the access point 3 is a table for storing a source address and a sequence number of a frame received by the access point 3 and managing received frames.

Radio reception buffer 3 of access point 3
Reference numeral 05 denotes a buffer for storing a frame received by the wireless transmission path 10, and a wireless transmission buffer 306 is a buffer for storing a frame to be transmitted by the wireless transmission path 10.

[0083] Wired reception buffer 3 of access point 3
Reference numeral 07 denotes a buffer for storing a frame received by the wired transmission path 4, and a wired transmission buffer 308 is a buffer for storing a frame to be transmitted by the wired transmission path 4.

[0084] Wired controller 309 of access point 3
Is a control unit that controls transmission and reception to and from the wired transmission path 4.

The FDB 310 of the access point 3 is a database that stores the MAC addresses of a plurality of wireless terminal devices 2a and 2b in the cell 1 to which the access point 3 belongs.

Relay control unit 311 of access point 3
Represents communication between the wired control unit 309 and the transmission / reception control unit 303;
For example, it is a control unit that exchanges transmission / reception frames.

Aging timer 3 of access point 3
Reference numeral 13 denotes a timer for deleting the MAC address stored in the FDB 310 after a lapse of a predetermined time from the writing.

On the wire transmission path 4 of the wireless LAN system according to the present embodiment, for example, IE
A format conforming to EE802.3 or Ethernet V2.0 is used.
An example of a frame conforming to E802.3 will be described.

FIG. 7 is a diagram showing an outline of a frame format used on the wired transmission path 4 in the wireless LAN system of the present embodiment. In FIG. 7, 40 is a frame format, 401 is an area PAM, 402 is an area SFD,
403 is the area DA, 404 is the area SA, 405 is the area L
NG, 406 is the area I, and 407 is the area FCS.

As shown in FIG. 7, the wireless LAN of this embodiment
The frame format used on the wired transmission path 4 of the system includes an area PAM401, an area SFD402, an area DA403, an area SA404, and an area LNG405.
, An area I406, and an area FCS407.

As shown in FIG. 7, the frame format used on the wired transmission path 4 of the wireless LAN system according to the present embodiment represents a frame format conforming to IEEE802.3. This area gives time to the physical layer for establishing and maintaining synchronization in the layer.

Area SFD4 of frame format 40
An area 02 indicates a substantial head of valid information in the present frame.

Area DA40 of frame format 40
An area 3 indicates a destination address, and an area SA40
An area 4 indicates a source address.

The area LNG4 of the frame format 40
An area 05 indicates the length of the area I406 which is the information section.

Area FCS4 of frame format 40
An area 07 indicates a frame check sequence, and detects an error in a frame excluding the area PAM401 and the area SFD402.
This area is used when notifying as a CS error.

Next, a method of constructing the FDB 310 in the access point 3 of the wireless LAN system according to the present embodiment will be described with reference to FIG.

In the wireless LAN system of the present embodiment, when the power of the wireless terminal 2a is turned on in the cell 1 of the access point 3 in the operating state, or when the powered wireless terminal 2a is in the operating state. When subscribing to the cell 1 of a certain access point 3, the wireless terminal device 2a transmits the FH-
The MAC frame is received, and the hopping pattern shown in FIG. 3 is obtained.

That is, the wireless terminal device 2a of the wireless LAN system of the present embodiment recognizes that it has joined the cell 1 by receiving the FH-MAC frame.

FIG. 8 is a diagram showing an outline of an FDB update control frame of the wireless LAN system according to the present embodiment.

As shown in FIG. 8, the wireless LAN according to the present embodiment
The FDB update control frame of the system indicates the content of a control frame that updates the content of the FDB 310 transmitted to the access point 3 by the wireless terminal device 2a that has recognized that it has joined the cell 1.

In the wireless LAN system of the present embodiment, the wireless terminal 2a that has recognized that it has joined the cell 1
Enables the bit indicating the control frame in the area FC93 of the FDB update control frame and sets the FDB update control information.

Further, the radio terminal device 2a stores the MA of the access point 3 in the area DA94 of the FDB update control frame.
C address, MAC of wireless terminal device 2a in area SA95
An address is set and an FDB update control frame (hereinafter NP)
-Described as a MAC frame) to the access point 3.

The NP-MAC frame is transmitted from the wireless terminal device 2a to the access point 3 when the timer expires at a shorter interval than the aging timer 313 of the access point 3 expires (for example, 30 seconds).

Although a plurality of MAC addresses are registered in the FDB 310 of the access point 3, each MAC address is registered.
The elapsed time from the writing time is monitored by the aging timer 313 for each address.
The MAC address that is not requested to be updated by the NP-MAC frame even after the elapse of the
Is erased from the FDB 310 as if it had left the cell 1 or the power was turned off.

The construction of the FDB 310 in the access point 3 is performed using the source address of the NP-MAC frame transmitted by the wireless terminal device 2a.

That is, the access point 3 receiving the NP-MAC frame in FIG. 8 extracts the MAC address of the wireless terminal device 2 a from the NP-MAC frame area SA 95, and checks whether the same MAC address exists in the FDB 310. Search for.

If the extracted MAC address of the wireless terminal 2a is not registered in the FDB 310, the MAC address of the extracted wireless terminal 2a is
At the same time, the aging timer 313 for the wireless terminal device 2a is activated.

Also, the M of the extracted wireless terminal device 2a is
If the AC address has already been registered in the FDB 310, the aging timer 313 for the wireless terminal device 2a is restarted.

As described above, the NP-MAC frame is transmitted from the wireless terminal device 2a existing in the cell 1 of the access point 3 at a time interval (for example, 30 seconds) shorter than the expiration time (for example, 5 minutes) of the aging timer 313. The transmission indicates that the wireless terminal 2a is present in the cell 1 of the access point 3 so that the wireless terminal 2a
The MAC address of “a” is registered in the FDB 310.

On the other hand, when the wireless terminal device 2a leaves the cell 1 of the access point 3 or is turned off, the access point 3
Aging timer 3 started or restarted at the time of last reception of the NP-MAC frame from a.
After the expiration of the timer 13, the MAC address of the wireless terminal device 2 a is deleted from the FDB 310.

FIG. 9 is a diagram showing an example of FDB registration in the wireless LAN system according to the present embodiment.

As shown in FIG. 9, the wireless LAN according to the present embodiment
In the FDB registration of the system, the MAC addresses stored in the FDB 310, more specifically, the plurality of wireless terminal devices 2a, 2b, 2c, 2 that transmitted the NP-MAC frame
d,... represents a state in which the MAC address of 2x is registered.

An area SA95, which is a transmission address, is extracted from the NP-MAC frame, and
In the area from “A1” to “SAn”, “SA1 = MAC address of wireless terminal device 2a”, “SA2 = wireless terminal device 2b”
MAC address ".

Hereinafter, the MAC layer retransmission control method of the wireless LAN system according to the present embodiment will be described with reference to (a) communication of a user frame from the wireless terminal device 2a to the wired terminal device 5,
(B) communication of a user frame from the wired terminal device 5 to the wireless terminal device 2a.

(A) Communication of User Frame from Wireless Terminal Device 2a to Wired Terminal Device 5 FIG. 10 is a diagram showing an example of MAC layer retransmission control in the wireless LAN system of the present embodiment. In FIG. 10, 10
1 is processing of an access point, and 102 is processing of a wireless terminal device.

As shown in FIG. 10, the wireless LA of this embodiment is
The MAC layer retransmission control of the N system has a process 101 of the access point and a process 102 of the wireless terminal device.

As shown in FIG. 10, in the MAC layer retransmission control of the wireless LAN system according to the present embodiment, the MAC frame retransmission processing when transmitting the user frame from the wireless terminal device 2a to the wired terminal device 5 is performed. Is represented.

In the wireless LAN system of the present embodiment, upon communication from the wireless terminal device 2 a to the access point 3, the wireless terminal device 2 a transmits from the personal computer 208 of FIG. And the user frame is
06, and a user frame transmission request is sent to the transmission / reception control unit 203, where a sequence number is added to the user frame.

FIG. 11 is a diagram showing an example of setting a user frame in the wireless LAN system according to the present embodiment.

As shown in FIG. 11, the wireless LA of this embodiment
In the user frame of the N system, the sequence number is 1
This shows a setting example in the case where bytes are allocated, in which a bit indicating a user frame is made valid for an area FC93 in a frame, and a sequence number is set.

Further, the transmission / reception control unit 2 of the wireless terminal device 2a
03 sets the MAC address of the wired terminal device 5 in the area DA94 and sets the MAC address of the wireless terminal device 2a in the area SA95.
Set the address.

In the wireless LAN system of the present embodiment, the set sequence number may start from an arbitrary number, but here, a case where the sequence number starts from “0000 0001” is shown.

The transmission / reception control unit 203 that has received the transmission request
A user frame is transmitted from the wireless transmission buffer 206 to the wireless transmission path 10 via the transmission / reception control unit 203, the wireless modulation / demodulation unit 202, and the antenna 201.

In this case, the frame format 9 on the wireless transmission path 10 shown in FIG. 4 is used.

In the access point 3 receiving the user frame, the frame is transmitted to the antenna 30 shown in FIG.
1 is temporarily stored in the wireless reception buffer 305 via the wireless modem 302 and the transmission / reception controller 303.

Here, the transmission / reception control unit 303 of the access point 3 performs the processing shown in the processing 101 of the access point in FIG.

(1) If the area DA94, which is the destination address of the received frame, is in the FDB 310, no response is returned to the wireless terminal 2a.
(2) The area DA94 which is the destination address of the received frame is not in the FDB 310,
If there is an FCS error, a response (NAK) indicating reception failure is returned to the wireless terminal device 2a, and the frame is discarded. If there is no error and no FCS error, the wireless terminal 2
A response (ACK) indicating successful reception is returned to a, and processing for relaying the frame to the wired transmission path 4 is started.

For the frame to enter the relay processing, the relay control unit 311 checks the source address and the sequence number using the sequence management table 304 and constructs the sequence management table 304.

To construct the sequence management table 304 of the access point 3, the sequence management table 304
A method of registering in the order of arrival of frames without overwriting within
There is a method of overwriting the same source address with a sequence number.

FIG. 12 is a diagram showing an example of the sequence management table 304 of the wireless LAN system according to the present embodiment.

As shown in FIG. 12, the wireless LA of this embodiment
The sequence management table 304 of the N system shows a case where the sequence number is registered in the sequence management table 304 without arrival in the sequence management table 304 and a case where the sequence number is overwritten on the same source address.

In the method of not overwriting the sequence management table 304 in the wireless LAN system of the present embodiment, if there is an empty space in the sequence management table 304, the sequence management table 304 is not overwritten and the received frames are received in the order of arrival. Register the source address and sequence number inside.

Therefore, as shown in FIG. 12A, the sequence management table 304 may include a plurality of pieces of information of the same source address.

If there is no free space in the sequence management table 304, the source address and sequence number registered at the oldest time in the sequence management table 304 are deleted, and then the source address and sequence number in the received frame are deleted. Is registered, the sequence management table 304 is constructed.

In the wireless LAN system according to the present embodiment, in the method of not overwriting the sequence management table 304, the source address and the sequence number are checked as follows.

That is, when the combination of the sequence number immediately before the combination of the source address and the sequence number in the received frame is registered in the sequence management table 304, or the source address and the sequence number in the received frame are Is not registered in the sequence management table 304, the frame is regarded as normally received and processed, and the sequence management table 304 is constructed. The source address and the sequence number match in the sequence management table 304. If there is one, the frame is discarded, and the sequence management table 304 is not changed.

On the other hand, in the method of overwriting the same source address with the sequence number, if the source address in the received frame is already registered in the sequence management table 304, only the sequence number in the received frame is subjected to sequence management. It is registered in the position corresponding to the source address in the table 304.

Therefore, as shown in FIG. 12B, the sequence management table 304 does not include a plurality of pieces of information of the same source address.

If the source address in the received frame is not registered in the sequence management table 304 and there is a space in the sequence management table 304, the source address and the sequence number in the received frame are stored in the sequence management table 304. If the source address in the received frame is not registered in the sequence management table 304 and there is no space in the sequence management table 304, the source address registered at the oldest time in the sequence management table 304 is registered. After deleting the sequence number and the sequence number, the sequence management table 304 is constructed by registering the transmission source address and the sequence number in the received frame in the sequence management table 304.

In the method of overwriting the sequence management table 304 in the wireless LAN system of the present embodiment, the source address and the sequence number are checked as follows.

That is, when the combination of the source address and the sequence number in the received frame is not registered in the sequence management table 304, the frame is received normally and the sequence management table 304 is constructed. The combination of the source address and the sequence number of the
If the frame has been registered, the frame is discarded, and the sequence management table 304 is not changed.

By checking the sequence management table 304, it is determined that the frame has not been received twice or more, and the frame determined to be normally received is stored in the wireless reception buffer 3.
5 is converted to the frame format 40 used on the wired transmission path 4 in FIG. 7 via the transmission / reception control unit 303 and the wired control unit 309, and then stored in the wired transmission buffer 308.

After that, as soon as the wire transmission path 4 becomes empty, the signal is transmitted from the wire transmission buffer 308 to the wire terminal device 5 via the wire control unit 309 via the route c in FIG.

The wireless terminal device 2a that receives a response from the access point 3 via the route b in FIG. 10 performs the process 102 of the wireless terminal device in FIG.

That is, (1) the radio terminal device 2a that has received the response (ACK) indicating the successful reception of the access point 3 counts up the sequence number and transmits the next frame. (2) Reception of the access point 3 The wireless terminal device 2a receiving the response (NAK) indicating the failure retransmits the sequence number after a random time without counting up. (3) If no response is returned from the access point 3, the wireless terminal device 2a
Performs a process of retransmitting after a random time without counting up the sequence number.

(B) From the wired terminal device 5 to the wireless terminal device 2
FIG. 13 is a diagram illustrating another example of the MAC layer retransmission control of the wireless LAN system according to the present embodiment. In FIG. 13, 1
31 is a process of the access point, and 132 is a process of the wireless terminal device.

As shown in FIG. 13, the wireless LA of the present embodiment
The MAC layer retransmission control of the N system includes an access point process 131 and a wireless terminal device process 132.

As shown in FIG. 13, in the MAC layer retransmission control of the wireless LAN system according to the present embodiment, the MAC frame retransmission process when the user frame is communicated from the wired terminal device 5 to the wireless terminal device 2a. Is represented.

In the wireless LAN system of the present embodiment, a user frame transmitted from the wired terminal device 5 using the frame format 40 used on the wired transmission line 4 in FIG. Is transmitted to the access point 3 via the route d.

At the access point 3, the user frame is temporarily stored in the wired reception buffer 307 via the wired control unit 309 in FIG.

Thereafter, the relay control unit 311 transfers the frame from the wired reception buffer 307 to the wireless transmission buffer 306 via the wired control unit 309 and the transmission / reception control unit 303.
To be stored.

At this time, the user frame is converted into a frame format 9 used on the radio transmission path 10 shown in FIG. 4 and stored.

Transmission / reception control section 303 of access point 3
Determines whether or not to relay to the wireless transmission path 10 with reference to the FDB 310.

FIG. 14 is a diagram showing an example of setting a user frame in the wireless LAN system according to the present embodiment.

As shown in FIG. 14, the wireless LA of this embodiment is
In the user frame of the N system, a setting example in the case of relaying to the wireless transmission path 10 is shown. In the case of relaying, the bit indicating the user frame is enabled for the area FC93 in the frame, and the sequence number is For example, “0001 0001” is set.

Further, the MAC address of the wireless terminal 2a is set in the area DA94 of the user frame, and the MAC address of the wired terminal 5 is set in the area SA95.

Upon receiving the transmission request, the transmission / reception control unit 303 transmits the data from the wireless transmission buffer 306 via the transmission / reception control unit 303, the wireless modulation / demodulation unit 302, and the antenna 301 via the path b in FIG.

In the wireless terminal device 2a receiving the user frame, the received user frame is temporarily transferred from the antenna 201 shown in FIG. 5 to the wireless reception buffer 205 via the wireless modulation / demodulation unit 202 and the transmission / reception control unit 203. Is stored in

Here, the transmission / reception control section 203 of the wireless terminal device 2a performs the process shown in the process 132 of the wireless terminal device in FIG.

(1) If the destination address DA of the received frame is not addressed to itself, the access point 3
(2) The destination address DA of the received frame is addressed to itself.
If there is an FCS error, access point 3
A response (NAK) indicating reception failure is returned and the frame is discarded. (3) If the destination address DA of the received frame is addressed to itself and there is no FCS error, the access point 3 receives it. A process of returning a response (ACK) indicating success and starting reception of the frame is performed.

For the frame that enters the receiving process, the transmission / reception control unit 203 checks the source address and sequence number.

If the source address and the sequence number set in the frame in the check of the source address and the sequence number are not in the sequence management table 204, the frame is regarded as not received twice or more and the frame is normally received. And the sequence management table 204 registers the source address and sequence number extracted from the frame.

In this case, the sequence management table 2
If there is no free space in 04, the sequence management table 2
After deleting the oldest source address and sequence number in 04, the source address and sequence number in the received frame are registered in the sequence management table 204.

On the other hand, if there is a sequence management table 204 in which the source address matches the sequence number, the frame is discarded on the assumption that the same frame has been received.

The construction of the sequence management table 204 is based on the sequence management table 30 in the access point 3.
4 is possible.

The frame which has been determined not to have been received twice or more and has been determined to be normally received is stored in the radio reception buffer 205.
Is transmitted to the personal computer 208 via the transmission / reception control unit 203 and the system bus 207.

The access point 3 receiving a response from the wireless terminal device 2a via the route a in FIG. 13 performs the process 131 of the access point in FIG.

That is, (1) the access point 3 that has received the response (ACK) indicating the successful reception of the wireless terminal device 2a counts up the sequence number and transmits the next frame. The access point 3 that has received the response (NAK) indicating the reception failure does not count up the sequence number and retransmits it after a random time. (3) If no response is returned from the wireless terminal device 2a, the access point 3
Performs a process of retransmitting after a random time without counting up the sequence number.

As described above, in the wireless LAN system of the present embodiment, the access point 3 which is the control terminal device receives a frame out of the cell 1 and transmits a response, so that the wireless terminal device 2a in the cell 1 In 2b and 2b, communication can be performed by the peer-to-peer distribution method, and communication with each wireless terminal device in another cell and the wired terminal device 5 connected to the wired transmission path 4 can be performed.

Further, in the wireless LAN system of the present embodiment, since communication is performed in the cell 1 by an equal distribution method,
It is possible to continue the communication in the cell 1 even when the access point 3 fails.

As described above, the wireless LA of the present embodiment
According to the N system, since the control terminal device receives a frame outside the cell and responds to the reception success or reception failure, the wireless terminal device in another cell or the wired terminal device connected to the wired transmission path It is possible to efficiently communicate with the server.

Further, according to the wireless LAN system of the present embodiment, since the frames of the sequence registered in the sequence management table are discarded, it is possible to prevent the frame from being received repeatedly.

Further, according to the wireless LAN system of the present embodiment, the source address and the sequence number of the received frame are registered in the order of arrival, so that it is possible to manage the sequence information in a processing procedure with a low processing load. .

Further, according to the wireless LAN system of the present embodiment, the sequence information of the received frame is overwritten and registered in the item corresponding to the source address, so that the sequence management for improving the prevention rate of receiving the duplicated frame is performed. It is possible to do.

Although the present invention has been specifically described based on the above embodiments, the present invention is not limited to the above embodiments, and it is needless to say that various modifications can be made without departing from the gist of the present invention. It is.

[0176]

The effects obtained by the representative ones of the inventions disclosed in the present application will be briefly described as follows.

(1) Since the control terminal device receives a frame outside the cell and responds to the reception success or reception failure, the radio terminal device in another cell or the wired terminal device connected to the wired transmission path. It is possible to efficiently communicate with the server.

(2) Since the frames of the sequence registered in the sequence management table are discarded, it is possible to prevent duplicate reception of the frames.

(3) Since the transmission source address and the sequence number of the received frame are registered in the order of arrival, it is possible to manage the sequence information in a processing procedure with a low processing load.

(4) Since the sequence information of the received frame is overwritten and registered in the item corresponding to the source address, it is possible to perform sequence management for increasing the prevention rate of receiving the duplicated frame.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a schematic configuration of a wireless LAN system according to an embodiment.

FIG. 2 is a diagram showing an outline of carrier frequency allocation in the wireless LAN system of the present embodiment.

FIG. 3 is a diagram illustrating an outline of a hopping pattern and a hopping cycle of the wireless LAN system according to the embodiment;

FIG. 4 is a diagram showing an outline of a frame format used on the wireless transmission path 10 of the wireless LAN system of the present embodiment.

FIG. 5 is a diagram showing a schematic configuration of wireless terminal devices 2a and 2b of the wireless LAN system of the present embodiment.

FIG. 6 is a diagram illustrating a schematic configuration of an access point 3 of the wireless LAN system according to the present embodiment.

FIG. 7 is a diagram showing an outline of a frame format used on the wired transmission path 4 of the wireless LAN system of the present embodiment.

FIG. 8 is a diagram illustrating an outline of an FDB update control frame of the wireless LAN system according to the embodiment.

FIG. 9 is a diagram illustrating an example of FDB registration in the wireless LAN system according to the present embodiment.

FIG. 10 is a diagram illustrating an example of MAC layer retransmission control of the wireless LAN system according to the present embodiment.

FIG. 11 is a diagram showing an example of setting a user frame in the wireless LAN system according to the embodiment.

FIG. 12 is a diagram illustrating an example of a sequence management table 304 of the wireless LAN system according to the present embodiment.

FIG. 13 is a diagram illustrating another example of the MAC layer retransmission control of the wireless LAN system according to the present embodiment.

FIG. 14 is a diagram illustrating an example of setting a user frame in the wireless LAN system according to the embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Cell, 2a and 2b ... Wireless terminal device, 3 ... Access point, 4 ... Wired transmission line, 5 ... Wired terminal device, 10 ...
Radio transmission path, 6 ISM band, 7a to 7m subchannel, 8 hopping cycle, 81 user frame area RU, 82 non-transmission area RN, 83 control frame area RC, 84 dummy area RD, 9 ... Frame format, 91 area P, 92 area F, 93 area FC, 9
4 Area DA, 95 Area SA, 96 Area I, 97
Area FCS, 201: antenna, 202: wireless modulation / demodulation unit, 203: transmission / reception control unit, 204: sequence management table, 205: wireless reception buffer, 206: wireless transmission buffer, 207: system bus, 208: personal computer, 209: local Bus, 301 antenna, 302 wireless modulation / demodulation unit, 303 transmission / reception control unit, 3
04: sequence management table, 305: wireless reception buffer, 306: wireless transmission buffer, 307: wired reception buffer, 308: wired transmission buffer, 309: wired control unit, 310: FDB, 311: relay control unit, 312: local bus , 313: aging timer, 40: frame format, 401: area PAM, 402: area S
FD, 403 ... area DA, 404 ... area SA, 405 ...
Area LNG, 406 ... Area I, 407 ... Area FCS, 1
01: access point processing, 102: wireless terminal processing, 131: access point processing, 132: wireless terminal apparatus processing.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kenichiro Oda 810 Shimo-Imaizumi, Ebina-shi, Kanagawa Prefecture Hitachi Systems, Ltd. Office Systems Division (72) Inventor Koji Aoyama 1-Horiyamashita, Hadano-shi, Kanagawa Japan Hitachi Within Information Technology (72) Inventor Masaaki Shida 1-280 Higashi Koigakubo, Kokubunji-shi, Tokyo Inside Central Research Laboratory, Hitachi, Ltd. (72) Inventor Mutsumi Hamasaki 810 Shimo-Imaizumi, Ebina-shi, Kanagawa Pref.

Claims (4)

[Claims] 1. A wireless LAN system for communicating with a wireless terminal device in another cell or a wired terminal device connected to a wired transmission path via a control terminal device, wherein a plurality of wireless terminal devices in the same cell are connected to each other. If the filtering database storing the address and the destination address of the received frame is in the filtering database, the received frame is discarded without returning a response indicating success or failure of reception,
If the destination address of the received frame is not in the filtering database, a response indicating success or failure of reception is returned.If there is an error in the received frame, the frame is discarded. A wireless LAN system comprising: a transmission / reception control unit that performs a reception process when there is no transmission processing. 2. The apparatus according to claim 1, further comprising a sequence management table indicating a sequence of the received frame, wherein when the sequence of the received frame is registered in the sequence management table, the frame is discarded. The described wireless LAN system. 3. When there is an empty space in the sequence management table, the source address and sequence number in the received frame are registered in the order of arrival of the received frame without overwriting the sequence management table, and when there is no empty space in the sequence management table. 3. The wireless communication method according to claim 2, wherein the transmission source address and the sequence number registered at the oldest time in the sequence management table are deleted and the transmission source address and the sequence number in the received frame are registered. L
AN system. 4. When the source address in the received frame is already registered in the sequence management table, only the sequence number in the received frame is registered in a position corresponding to the source address in the sequence management table. If the source address in the received frame is not registered in the sequence management table and there is a space in the sequence management table, the source address and sequence number in the received frame are registered in the sequence management table, and If the source address is not registered in the sequence management table and there is no space in the sequence management table, the source address and sequence number registered at the oldest time in the sequence management table are erased and received. The source address and sequence number in the frame are stored in the sequence The wireless LAN system according to claim 2, wherein the wireless LAN system is registered in a management table.