JP2003087264A - Wireless lan system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that a communication fault occurs by a competition in communication when a plurality of wireless LAN systems adjacently exist which originally and mutually conduct asynchronous communication in a diffusion type optical wireless LAN system without having a plurality of channels. SOLUTION: When communication is performed concerning the station STAb of a system A included in the communication range of a system B, the access point 11 of the system A transmits a lock request to the system B via a cable LAN 17 (103). Then the system A becomes a replay waiting state 104. The access point 16 of the system B transmits a replay when the lock request is received from the system A and, then, becomes a state where the usage of a radio space is withheld, i.e., a lock release waiting state 203. When the reply is received from the system B, the access point 11 in the reply waiting state starts the communication of the station STAb through the use of the wireless space as shown in 105.

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, and more particularly to one or more stations that are wireless terminals and one access point having a mechanism for granting wireless data transmission right to the stations. The present invention relates to a centralized control wireless LAN system.

[0002]

2. Description of the Related Art Compared to a radio wave type wireless LAN system and a beam type optical wireless LAN system, the device configuration is simpler and the optical axis alignment unlike the beam type optical wireless LAN system is not necessary, so that the user can easily carry out the operation. There is known a diffusion type optical wireless LAN system which can be installed.

This spread type optical wireless LAN system is composed of one or more stations which are wireless terminals, and one access point having a mechanism for granting wireless data transmission right to the stations. In such a diffused optical wireless LAN system, it is necessary to prevent an area where communication is not possible even if access points and stations are roughly installed.

[0004]

However, since the diffusion type optical wireless LAN system has a narrower communication range than the radio type wireless LAN system, for example, there should be no area where communication cannot be performed on the floor of one office. In order to construct the system, a plurality of diffused optical wireless LAN systems are required. In the wireless LAN system of the radio wave system, communication failure due to frame collision is avoided by setting adjacent systems to use wireless channels of different frequencies.

However, in a diffused optical wireless LAN system that does not have a plurality of channels, if a plurality of centralized control type wireless LAN systems that originally perform asynchronous communication are adjacent to each other, they share a wireless space. Communication conflict occurs and communication failure occurs. For example, in FIG. 7, an access point APα having a communication range 1, a station STA 1 having a communication range 2, and a communication range 3
First spread type optical wireless LAN system α including a station STA2 having a communication range, an access point APβ having a communication range 4, a station STAa having a communication range 5, and a station STAb having a communication range 6.
When the second diffusion type optical wireless LAN system β consisting of is adjacent to each other, the access point APα having a mechanism for granting the wireless data transmission right to the stations STA1 and STA2 and the stations STAa and ST
An access point APβ having a mechanism for granting a wireless data transmission right to Ab does not include the other access point in its communication range 1 or 4, but the communication range 1 of the access point APα is the other system. Station STAa, and station STAa
Communication range 5 is the access point AP of the other system
Since they depend on α, they influence each other.

Therefore, in this case, there is a possibility that communication of all stations will fail, and the influence thereof is great.
For example, when the communication schematically shown in FIG. 9 is being performed, the access point recognizes the communication failure immediately before the communication with the stations indicated by the arrows I, II, and III ends. This is because unlike a wired LAN system, it is difficult to detect a collision at the time of frame transmission in a wireless LAN system. Therefore, if it is attempted to determine whether or not the communication succeeds in the data link layer or below, the communication ends. This is because it has no choice but to judge the normal end of communication by the response signal from the station when there is no data to be transmitted.

FIG. 8 shows another example in which two adjacent wireless LAN systems cause communication competition. In the figure, an access point APα having a communication range 1, a station STA 1 having a communication range 2 and a communication range 3
A first spread type optical wireless LAN system α including a station STA2 having a communication range, an access point APγ having a communication range 7, a station STA A having a communication range 8 and a station STA B having a communication range 9. When the second diffusion type optical wireless LAN system γ is adjacent to the second spread type optical wireless LAN system γ, the access point APα having a mechanism for granting the wireless data transmission right to the stations STA1 and STA2 and the stations STAA and ST
The access point APγ having a mechanism for granting the wireless data transmission right to A does not include the partner access point in its communication range 1 or 7, but the communication range 3 of the station STA2 is the other system. Station STA, and includes station STA
A communication range 8 is the station STA of the other system
Since they contain 2, they influence each other.

Therefore, in this case, the station STA
When two and the station STA communicate at the same time, a communication failure may occur. For example, when the communication schematically shown in FIG. 10 is performed, the access point recognizes the communication failure at the end of the communication between the station STA2 and the station STA2 indicated by arrows IV and V.
7 and 9, the communication content includes the identification code of the wireless LAN system to which the station or access point issuing the communication belongs.

The present invention has been made in view of the above points,
It is an object of the present invention to provide a wireless LAN system capable of avoiding communication stagnation caused by repeated contention of communication due to the same cause, instead of seeking the most effective method of granting a data transmission right at that moment. .

[0010]

In order to achieve the above-mentioned object, the present invention provides a wireless system comprising one or more stations, which are wireless terminals, and an access point which gives the station the right to transmit wireless data. A wireless LAN system in which a plurality of communication systems exist adjacent to each other and each access point gives a transmission right to a station in its own system asynchronously with an access point of another system, and each access of a plurality of wireless communication systems The point is
Of the stations of the own system, the first queue that stores the address of the station that grants the right to transmit data asynchronously with other wireless communication systems, and the exclusive use of the wireless space as a result of detecting the communication failure Exclusion of wireless space from a storage device having a second queue storing the address of the attempting station, a lock request queue storing the system requesting exclusive use of the wireless space, and an access point of another system When a request for use, a request for release of exclusive use, or a response for permission for exclusive use is received, and a request for exclusive use of the wireless space is received, the transmission source system is placed in the lock request queue according to a predetermined priority order, and the exclusive request is placed. Inter-system communication receiving means for deleting the source system from the lock request queue when a release request for use is received It is obtained by a structure having a first through fourth processing means.

Here, when the station in the system to which the transmission right is to be given is in the first queue of the storage device, the first processing means gives the transmission right to the station. The second processing means sends a request for exclusive use of the wireless space prior to granting the transmission right to the station in the own system in the second queue of the storage device, and predetermines the own system. When the station in the local system that has completed the communication is at the end of the second queue, it sends a request to release the exclusive use of the wireless space and at the same time sets the local system from the lock request queue. delete.

Further, the third processing means, when the own system is stored at the head of the lock request queue, waits until the intersystem communication receiving means receives the exclusive use permission response, and locks the exclusive system. When the use permission response is received, the transmission right is given to the station in the own system which is to be given the transmission right in the second queue. Further, the above-mentioned fourth processing means receives the exclusive use request by the intersystem communication receiving means, and when another system is stored at the head of the lock request queue,
Send the permission response for exclusive use.

According to the present invention, since a plurality of wireless communication systems are adjacent to each other when a communication failure occurs,
The range of stations within a wireless communication system,
From the first queue to the second queue, it is considered that the communication range of an access point or a station in another wireless communication system overlaps with each other, and it is possible that they interfere with each other due to competitive use of wireless space. Before the access point grants the transmission right to the station whose address is stored in the second queue, it sends a request for exclusive use of the radio space to another access point to Avoiding the conflict of wireless space use because the system waits for the exclusive use permission response of the wireless space, and after the exclusive use permission response is received, the transmission right is given to the above station. You can

Further, the present invention is characterized in that the respective access points in the plurality of wireless communication systems are connected to each other by a wired LAN. As a result, communication between the access points can be performed without competition for use of the wireless space.

Here, when each of the plurality of wireless communication systems is a light diffusion type wireless LAN system, the diffusion type wireless LAN system does not have a plurality of channels and is particularly effective.

Further, in the present invention, the station included in the first queue moves to the second queue upon the failure of the wireless communication, and the station moved to the second queue changes the system to another system. It is characterized by returning to the first queue upon receiving no communication of the above.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings. 1 (A) and 1 (B) are respectively a system configuration diagram of an embodiment of a wireless LAN system according to the present invention and an operation explanatory diagram of essential parts. In FIG. 1A, an access point 11 and a station (STA
a) 12, station (STAb) 13, station (STAc) 14, and station (STAd) 15
Comprises the first wireless LAN system A, and the access point 11 gives a transmission right to any one of the stations 12 to 15 and passes between the stations 12 to 15 via the access point 11. Communication is possible,
The stations 12 to 15 can also communicate with a communication terminal (not shown) via the wired LAN 17.

The access point 16 is also connected to a first wireless LAN together with one or more stations (not shown).
A second wireless LAN system B adjacent to the system A is configured, and a station in the second wireless LAN system B can be given a transmission right to communicate.
Here, assuming that the communication range of the access point 16 includes the stations 13 and 14 in the adjacent wireless LAN system A, in that case, the station 13
And 14 cause communication failures.

Therefore, in this embodiment, the above-mentioned communication failure can be avoided by providing the access point with means for enabling exclusive use of the wireless space. That is, access points 11 and 1
6 is a queue (a polling list) of stations that are originally targets of data transmission right to the wireless space.
Has a storage device in which is stored.

In this embodiment, as a result of transiting the transitional state as shown in FIG. 2, in the case of the access point 11, as shown in FIG. The queue is added to the normal queue in which the access point 11 grants the data transmission right to the stations 12 and 15 asynchronously with other systems, and the station 13 that attempts the exclusive use of the wireless space as a result of the detection of the communication failure. (STAb) and 14 (STAc) queues, and a queue of a system requesting exclusive use of wireless space.

As described above, the pointer 21 of the normal queue described above is a storage device of a structure in which information indicating the station 12 (STAa) is written, assuming that the wireless state of the wireless LAN system is stable. It fixedly points to the above address. Also, station 12
The address of the structure of (STAa) is station 15
It indicates the address of the structure of (STAd), and the structure of the station 15 (STAd) indicates "0" which means the end.

The pointer 22 to the queue of the station requiring the exclusive use of the wireless space is the station 13 among the stations 13 and 14 included in the communication range of the access point 16 of the adjacent wireless LAN system. The address on the storage device of the structure in which the information indicating (STAb) is written is fixedly indicated. The address of the structure of the station 13 (STAb) points to the address of the structure of the station 14 (STAc), and the structure of the station 14 (STAc) points to "0", which means the end.

Further, the queue of the system requesting the exclusive use of the wireless space indicated by the pointer 23 is the wired LAN 17 of the system requiring the exclusive use of the wireless space.
The request source system is added by the above request, and the request source system is deleted by the release request on the wired LAN 17. In the example of FIG. 1B, the access point 11 is a station 13 (S which is the head element of the queue of stations requiring exclusive use of the wireless space).
Before granting the transmission right to TAb), the exclusive use of the wireless space is requested on the wired LAN 17 (lock request), and the wireless communication is waited for by a response (reply) from the other access point 16 to allow the exclusive use of the wireless space. And the release of the wireless space (lock release) is requested on the wired LAN 17 after the communication of the station 14 (STAc), which is the last element of the queue of the station requiring the exclusive use of the wireless space, is completed.

Therefore, when the wireless LAN system is stably operated without moving stations or obstacles, the two queues pointed to by the pointers 21 and 22 are also stable, whereas the pointer 23 is The pointing queue changes dynamically, whether it is empty or access point 11 only, access point 16 only, access point 1
Includes both 1 and 16. Therefore, in FIG. 1 (B), the queue pointed to by the pointer 23 dynamically changes even in a steady state, and is not shown.

FIG. 2 shows the transition of the queue to which each station belongs in the system of the present invention. In the figure, all stations in one wireless LAN system are initially put in a normal queue 31 in response to a registration request 25 from the station. When the access point 11 detects a communication failure due to a temporary communication failure due to a moving obstacle or a competition for wireless space use with an adjacent wireless LAN system, the access point 11 gives the station which has given the data transmission right at that time. Is moved from the normal queue 31 to the queue 32 of the station requiring exclusive use of the radio space as shown by the arrow 26, and the next transmission right is transmitted to the next station belonging to the normal queue 31. give.

The access point 11 that has called the station registered in the normal queue 31 gives the right of data transmission to the head station of the queue 32 of the station that requires exclusive use of the radio space. Before using the wired LAN17, another access point 16
Exclusive control of the wireless space is performed between and. The access point 11 also releases the wireless space using the wired LAN 17 when the communication with the last station in the queue 32 of the station that requires exclusive use of the wireless space is completed.

During this exclusive control period, competition with other adjacent systems does not occur. Therefore, the communication failure at this time may be a temporary communication failure due to a moving obstacle or the like, or a power-off of the station. The access point 11 removes the station from the queue 32 as indicated by an arrow 27 in FIG. 2 when the communication of the same station continuously fails despite the exclusive control period. Note that when a communicable state is entered due to movement of an obstacle or power-on, the station is re-installed in the normal queue 31 by a registration request 25 from the station.

On the other hand, a station incorporated in the queue 32 of a station that requires exclusive use due to a communication failure due to a competition for wireless space use with an adjacent wireless LAN system or the like is the source of communication conflict. The communication of the adjacent wireless LAN system has become visible. This is because the station of the adjacent wireless LAN system, which is the source of the communication conflict, also performs the communication during the exclusive control period, and during that time, the own system refrains from the wireless communication. Therefore,
The disappearance of the cause of the communication conflict due to the power-off or movement of one of the stations that have been in contention for communication with each other can be determined by the fact that the communication of the other system, which was previously received, cannot be continuously received. That is, the return from the queue 32 of the station requiring exclusive use of the wireless space to the normal queue 31 is triggered by the request 28 from the station to the access point 11.

FIG. 3 is a flow chart for explaining the operation of an embodiment of an access point which constitutes a main part of the wireless LAN system according to the present invention. First, the access point respectively sets a flag waitReply that means waiting for a reply from another access point, a flag recvLock that means that there is a wireless space lock request from another system, and a flag waitUNLK that means wait for lock release. It is initialized to 0 (step 40).

Subsequently, the access point performs a station fetch process for selecting a station from the queue (step 50) and then a request handler process for satisfying the pre-communication requirements (step 6).
0). Then, the access point performs data communication with the station (step 70). After that, the processes of steps 50, 60 and 70 are repeated.

Next, the station fetch process 50 of step 50 will be described in more detail with reference to the flowchart of FIG. In a station fetch, the access point first reads the current pointer in the polling list (queue) (step 51), and that pointer points to the last station in the queue of stations requiring exclusive use of radio space. It is determined whether or not there is (step 52).

If the current pointer does not point to the last station in the queue of stations requiring exclusive use of the radio space, the next station is taken from its poll list (step 53), the current station. It is judged whether or not the pointer of is the head station of the queue of the station requiring exclusive use (step 54). When the station is the first station, a wireless space lock request is issued to the wired LAN 17 (step 55), and the system (because there is only one access point in the system) according to a predetermined priority order unique to each access point. Information about the access point is also acceptable (step 56), which is incorporated into the lock request queue (ie, the queue of the system requesting exclusive use of the radio space). Only the system is installed in the lock request queue.

Then, a flag waitReply, which means waiting for a reply from another access point, is set for exclusive use of the wireless space (step 57). And
A request handler process 60 described below is performed.
If the exclusive use of the wireless space of the own system is permitted by another system, the above-mentioned steps 52 to 52 are performed until the current pointer points to the last station of the queue of the station requiring the exclusive use of the wireless space.
Processes 54 and 60 are performed.

When the current pointer points to the last station in the queue of stations requiring exclusive use of wireless space, a wireless space lock release request is issued to the wired LAN 17 (step 58), and the access point is reached. It is removed from its own embedded lock request queue (ie, the queue of the system requesting exclusive use of the radio space) (step 59). Thereafter, the request handler process 60 is performed via steps 53 and 54.

Next, the above-mentioned request handler processing 60 will be described in detail with reference to the flowchart of FIG. In the request handler processing 60, the access point 11 first determines whether or not the flag recvLock, which means that there is a wireless space lock request from another system, is set (step 61). The flag
When recvLock is not set, it is judged whether or not the flag waitUNLK which means waiting for lock release is set (step 62).

When the above-mentioned flag waitUNLK is not set, that is, when it is not waiting for the lock release,
The access point 11 determines whether the lock request queue is empty (step 63). Access point 11
If the lock request queue is empty, it judges whether or not the flag waitReply, which means waiting for a reply from another access point, is set (step 64).

If this flag waitReply is not set, the process proceeds to step 70 and the access point 11
Polls the station in its own system taken out in step 50 and performs wireless communication. That is, when no system requests exclusive use of the wireless space, the paths of steps 61 to 63, 65, 64, and 70 are taken.

On the other hand, in step 61, a flag recvLo indicating that there is a wireless space lock request from another system.
If it is determined that ck is set, the flag re
cvLock is reset to 0 (step 67), and it is determined whether the head of the lock request queue is the own system (step 68). If the beginning is not the own system, when the own system does not need exclusive use of the wireless space,
A lock request has been received from another system, or a lock request has already been issued and waiting for a reply (step 61).
~ 63, 65, 64 are repeatedly executed)
Since this means that a lock request of a system with a higher priority has been received, a reply is transmitted, and a flag waitUNLK, which means waiting for lock release (that is, waiting for free radio space), is set to 1 (step 69), Return to step 61.

As a result, the access point 11
Until the flag waitUNLK is reset by receiving a lock release request from another system in the inter-system communication reception process, the processes of steps 61 and 62 are repeated and the wireless communication is withheld.

On the other hand, when it is determined in step 68 that the head of the lock request queue is the own system (that is, the system having the highest priority requesting the use of the wireless space is still the own system), the own system , Which means that the exclusive use of the wireless space has already been requested, and the process of waiting for a response from another system (steps 62, 63, 6).
5, 64, 61).

At this time, when the flag waitReply is reset by receiving a reply meaning an affirmative response from the other system to the lock request of the own system in the inter-system communication receiving process described later, the access point 11 The process of waiting for a response from another system is skipped, and the process proceeds to the communication process of step 70. In this way, when the request for exclusive use of the wireless space is acknowledged by the other system and the lock of the wireless space is completed, the request immediately after the station is removed from the queue of the station that requires the exclusive use of the wireless space thereafter. In the handler, exclusive wireless communication can be continued through steps 61 to 63, 65, 64, and 70.

In this way, when the exclusive use of the radio space by the own system ends, the own system (address of the own system) is removed from the lock request queue, as already described in the processing of station fetch.
Then, in the next call of the request handler, the following processing is performed after steps 61, 62 and 63. That is, in step 63, if the lock request queue is empty, it means that there is no other system requesting exclusive use of the wireless space, and the process proceeds to steps 64 and 70 to perform wireless communication. .

On the other hand, if it is determined in step 65 that the head of the lock request queue is not the head itself (that is, if there is another system requesting the use of the radio space), the radio space of the own system described in the processing of the station fetch. The lock release request removes the local system (address of the local system) from the lock queue, or multiple systems other than the original system originally issued the lock request, and one of them has exclusive use of the wireless space. As a result of issuing the lock release request for the wireless space after completing the above, the next other system appears.

Therefore, when it is determined in step 65 that the head of the lock request queue is other than itself, a reply is transmitted for the system, and a flag indicating a lock release wait (that is, a wait for a radio space) is sent. wa
Set itUNLK to 1 (step 66) and step 61
Return to. At this time also, the access point 11 repeats the processing of steps 61 and 62 until it receives the lock release request from the other system in the inter-system communication reception processing and resets the flag waitUNLK, and refrains from wireless communication. become.

Next, a process (or thread) that is independent of the main operation described with reference to FIGS. 3 to 5 operates, and a request from another access point comes in via the wired LAN 17. The operation of the inter-system communication reception process for notifying the main operation only at this time will be described with reference to the flowchart of FIG. In the inter-system communication reception process, the access point 11 first performs inter-system communication by the wired LA.
When it is received via N17 (step 81), it is determined whether or not the received intersystem communication is a reply to allow the exclusive use of the wireless space from another system to the lock request of the wireless space (step 82).

If it is a reply, after storing the wireless LAN system that returned the reply (step 8)
3) It is determined whether the lock is completed (step 84).
Whether or not the lock is completed is determined by the fact that replies are received from all healthy systems that share the wireless space with the own system other than the own system. Specifically, for example, periodic communication is performed to check whether there is a response, and the system that does not respond is determined to be a system that has lost communication due to a power failure or a failure on the wired LAN 17. Remove the valid bit from the system list acquired in advance and remove it from the reply judgment target system.

If the lock is not completed, the process returns to the first step 81, and if the lock is completed, the flag waitReply which means that it is necessary to wait for a reply from another access point is reset (step 85). , Return to the first step 81.

On the other hand, when it is determined in step 82 that the received intersystem communication is not a reply to the wireless space lock request, it is determined whether the received intersystem communication is the wireless space lock request (step 8).
6) If it is determined that the request is a lock request, the request source (sender) is assigned according to the priority order of the system that issued the lock request.
Place system in lock request queue (step 8)
7). Then, a flag recvLock indicating that there is a wireless space lock request from another system is set (step 88), and the process returns to the first step 81. In steps 87 and 88, interrupts are disabled so that no process switching occurs during this period.

When it is determined in step 86 that the received intersystem communication is not the wireless space lock request, it is determined whether the received intersystem communication is the wireless space lock release request (step 89) and the lock release request is issued. If it is determined that the system is removed from the lock request queue, the flag waitUNLK, which means waiting for lock release, is reset (step 91) and the process returns to the first step 81. If it is determined in step 89 that the request is not a lock release request, nothing is done and the first step 8
Return to 1.

With the above operation, according to the present embodiment, for example, the system A and the system B shown in FIG.
Performs the communication operation schematically shown in FIG. Here, access point 11 and station 12 (ST
Ab), 13 (STAb), 14 (STAc) and 15
An example will be described in which the system A including (STAd) succeeds in the exclusive control of the wireless space and the system B including the access point 16 and one or more stations (not shown) temporarily withholds wireless communication.

Depending on the timing, the system A
Both B and B may issue a wireless space lock request at the same time, but in this example, it is assumed that the lock request comes from the system A at a timing when the system B does not need exclusive use of the wireless space. I'm assuming. It should be noted that, when the lock requests compete with each other, the system that has decided to have a higher priority makes exclusive use of the wireless space as described above.

Stations STAa and STAd which are not included in the communication range of other system of system A are shown in FIG.
A case in which the station STAb included in the communication range of the system B communicates after the transmission right is given from the access point 11 and the communication is sequentially performed, as schematically shown by 101 and 102 in FIG. The access point 11 performs the main operation of FIG. 3, and in the station fetch process 50, reads the current pointer of the polling list (step 51 of FIG. 4) and determines whether it is the last pointer for exclusive control. (Fig. 4
Step 52). Here, since the current pointer is the station STAd that was communicated with immediately before, the station ST that is the next station from the polling list.
Ab is read (step 53 in FIG. 4), and it is determined whether the pointer is the head for exclusive control (step 54 in FIG. 4).

Since the pointer of the station STAb is the head for exclusive control, the access point 11 is connected to the wired L
A lock request is transmitted to the system B via the AN 17 (step 55 in FIG. 4). This lock request is shown in FIG.
It shows with 03. Then, the access point 11 performs steps 56 and 57 in FIG. 4, step 61, step 62, step 63, step 65, and step 6 in FIG.
4. The process of step 61 is sequentially performed. That is, system A waits for a reply from system B. This waiting for reply is indicated by 104 in FIG.

On the other hand, the access point 16 of the system B
Receives the intersystem communication from system A (step 81 in FIG. 6) and determines whether it is a reply (FIG. 6).
82), it is not a reply, so it is determined whether it is a lock (step 86 in FIG. 6). Since the received intersystem communication is the lock request, the access point 16
Thereafter, the processes of steps 87 and 88 in FIG. 6 are sequentially performed, and the process returns to the first step 81 to enter a waiting state for intersystem communication reception.

Further, the access point 16 of the system B
Is the station fetch 50, request
The processing of the handler 60 is sequentially executed. In the processing of the request handler 60, the access point 16
Reply transmission is performed in step 69 of FIG. 5 after each processing of steps 61, 67, and 68 of FIG.
Set UNLK.

Therefore, as shown in FIG. 1C, the system B changes from the state (201) during communication with its own station to
This is the state (202) of the reply transmission. At this time,
The access point 16 uses steps 61, 62,
The processing of 61 is repeated. Therefore, the access point 16 continues the processing of the request handler 60, does not shift to the communication processing 70 of FIG. 3, and is in a situation where the use of the wireless space is withheld. That is, the system B is in a lock release waiting state, as indicated by 203 in FIG.

Next, the access point 11 waiting for the reply receives the inter-system communication from the system B via the wired LAN 17 (step 81 in FIG. 6), and the received inter-system communication is the reply. The system B that returned the reply is stored (step 8 in FIG. 6).
2, 83), and it is determined whether the lock is completed (step 8 in FIG. 6).
4). Since there are only two systems here, A and B,
When it is determined that the lock is completed, the flag waitReply is reset (step 85 in FIG. 6), and the system waits for inter-system communication reception in step 81.

Further, the access point 11 executes the processing of the request handler 60 shown in FIGS. 3 and 5, and the flag waitReply is set in step 64 via the processing of steps 61, 62, 63 and 65. It is determined whether or not there is a flag waitReturn in step 85 described above.
Since ply has been reset, communication processing is executed (step 70). With this, the reply waiting from the system B is released, and the communication of the station STAb of the current pointer of the polling list is performed using the wireless space.
The process starts at 105 in (C).

Next, while the system A is occupying the wireless space, the access point 11 is the next station STA.
At the time of fetching c, the processing of steps 50 and 60 of FIG. 3 is executed, and the request handler 60 of step 60 executes steps 61, 62, 63, 65 and 64 of FIG.
The processing of 70 is sequentially executed. This allows system A
1 occupies the wireless space, the station STAc is given a transmission right as shown by 106 in FIG.

The access point 11 of FIG. 4 has the current pointer in the polling list pointing to the last station STAc in the queue of stations requiring exclusive use of the radio space shown in FIG. 1B. A lock release request is transmitted in step 58 through steps 50, 51 and 52. This lock release request transmission is shown in FIG.
This is indicated by 07.

After transmitting the above lock release request, step 5
At 9 removes itself (system A) from the lock request queue and at step 53 the next station STAa is taken from the polling list. After that, the processing of step 54 and steps 61, 62, and 63 of FIG. 5 are sequentially performed. Depending on the timing, the lock request queue may or may not be empty in step 63. However, assuming that the lock request queue is empty here, the access point 11 subsequently
After step 64, the process proceeds to the communication process of step 70,
Grant the transmission right to the station STAa.

On the other hand, the access point 16 of the system B which has received the above-mentioned transmission of the lock release request from the system A, the steps 81, 82, 86, 89 and 9 of FIG.
After each processing of 0 and 91, the system enters the state of waiting for inter-system communication reception in step 81. In addition, access point 16
Is the request handler process 60 during the main operation.
After step 61, it is determined whether the flag waitUNLK is set.

Here, since the access point 16 of the system B resets the flag waitUNLK in the inter-system communication reception process when the lock release request is received (step 91 in FIG. 6), the step 63 in FIG. Go to
Determine if the lock request queue is empty. Depending on the timing, the lock request queue may or may not be empty in step 63. However, assuming that the lock request queue is empty in this case, the access point 16 subsequently proceeds to step 6
4, the process shifts to the communication process of step 70, and the system B
Grant the right to send to the next station in. In this manner, the system B can safely exit the lock release waiting loop and resume wireless communication.

The present invention is not limited to the above embodiment, and for example, it is not necessary to provide only one station in the system (in this case,
Of course the queue is either a normal queue or the queue of stations that require exclusive use of radio space is empty).

[0065]

As described above, according to the present invention,
Before the access point grants the transmission right to the station of its own system, which causes a conflict in the use of wireless space with other systems, it waits for the exclusive use of the wireless space from the other system and waits for a response to allow the exclusive use. After receiving the response, by granting the transmission right to the above station, to avoid the conflict of use of the wireless space,
It is possible to prevent communication from stagnating due to repeated frame collisions of a plurality of wireless LAN systems sharing a wireless space.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a system configuration diagram, a configuration diagram of a main part, and a communication operation according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of transition of a queue to which a station belongs in the system of the present invention.

FIG. 3 is a flowchart showing an example of a main operation of an access point in the system of the present invention.

FIG. 4 is a flow chart for explaining processing of station fetch in FIG.

5 is a flowchart for explaining the processing of the request handler in FIG.

FIG. 6 is a flowchart of inter-system communication reception processing of an access point in the system of the present invention.

FIG. 7 is a diagram showing an example of how a station interferes with an access point of another system.

FIG. 8 is a diagram showing an example of how a station interferes with a station of another system.

9 is an explanatory diagram of an example of a communication failure in FIG.

10 is an explanatory diagram of an example of a communication failure in FIG.

[Explanation of symbols]

11 System A access points 12 (STAa), 13 (STAb), 14 (STA
c), 15 (STAd) Station of system A 16 Access point of system B 21 Pointer to normal queue of station 22 Pointer to queue of station requiring exclusive use of radio space 23 Exclusive use of radio space Pointer to queue of system requesting request 50 Station fetch processing step 60 Request handler processing step 70 Communication processing step

Claims (4)

[Claims] 1. A plurality of wireless communication systems including one or more stations, which are wireless terminals, and access points that grant wireless data transmission right to the stations are adjacent to each other, and each access point is connected to another station. Is a wireless LAN system that gives a transmission right to a station in its own system asynchronously with an access point of the other system, wherein each access point of the plurality of wireless communication systems is the other wireless communication among the stations of the own system. A first queue that stores the address of the station that grants the right to transmit data asynchronously with the system, and a second queue that stores the address of the station that attempts to use the wireless space exclusively as a result of detection of a communication failure. Queue and a lock request queue that stores the system that requested exclusive use of the wireless space. When receiving a request for exclusive use of wireless space, a request to release exclusive use or a permission response to exclusive use from the storage device and an access point of another system, and a request for exclusive use of the wireless space is received, Inter-system communication receiving means for incorporating the transmission source system into the lock request queue according to a predetermined priority, and deleting the transmission source system from the lock request queue when the exclusive use release request is received, When the station in the system to which the transmission right is to be granted is in the first queue of the storage device,
First processing means for granting a transmission right to the station, and a request for exclusive use of the wireless space prior to granting the transmission right to a station in its own system in the second queue of the storage device And release the exclusive use of the wireless space when the station in the own system which has completed the communication is at the end of the second queue in addition to sending Second processing means for transmitting a request and deleting the own system from the lock request queue; and, when the own system is stored at the head of the lock request queue, the exclusive use by the intersystem communication receiving means. Waiting state until the permission response is received, and when the permission response for the exclusive use is received, the queue is added to the second queue. Third processing means for granting a transmission right to a station in the system to which the transmission right is to be granted, and the inter-system communication receiving means for receiving the exclusive use request, and at the head of the lock request queue. A wireless LAN system comprising: a fourth processing means for transmitting the exclusive-use permission response when another system is stored. 2. The wireless LAN according to claim 1, wherein the access points in each of the plurality of wireless communication systems are connected to each other by a wired LAN.
system. 3. The wireless LAN system according to claim 1, wherein each of the plurality of wireless communication systems is a light diffusion type wireless LAN system. 4. A station included in the first queue moves to the second queue upon failure of wireless communication, and a station that moves to the second queue communicates with another system. 2. The wireless LAN system according to claim 1, wherein the wireless LAN system returns to the first queue when the reception of the message is stopped.