JPH08274777A - Local area network radio communication system - Google Patents

Abstract

PURPOSE: To expand a communication area without requiring a dedicated radio wave repeater device by allocating a terminal itself in a system to a repeater station and to enable a terminal which serves system to a repeater station and to enable a terminal which serves as an originating station to easily select a repeater station candidate terminal on the basis of a communication correlation table when repeating is required. CONSTITUTION: The radio communication function that the terminal itself in the system has is utilized to make a radio repeated communication by using the terminal itself in the system as the repeater station. Each terminal in the system checks whether the terminal can have a direct communication, terminal by terminal, before entering an ordinary communication mode. The investigation results of the respective terminals are put together to generate the communication correlation table, showing whether or not direct communications can be made as to all the terminals in the system, in the system; an originating station for data selects a repeater station candidate terminal on the basis of the communication correlation table and sends out a packet showing repeating route information.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a LAN (Local Area N
etwork) for a wireless LAN communication system using electromagnetic waves as a communication medium.

[0002]

2. Description of the Related Art As a conventional communication between terminals, there is a wired LAN system in which a plurality of terminals are mutually connected by a communication cable. As an example of a wired LAN system, as shown in FIG. 40, a plurality of satellite machines S installed in a closed area are provided.
_There are a master / satellite system in which one master machine M centrally manages ₁ · S ₂ ... S _n , and a client / server system in which workstations and personal computers are interconnected.

In the case of the above wired LAN system, it is necessary to connect the terminals with a communication cable, which is troublesome in laying the cable and there is a problem that construction cost for that is required.

[0004] For example, as a representative of the master satellite system, a PO that centrally manages input information of a plurality of cash register machines installed in a store by a host computer
There is an S (poit of sale) system, but when introducing this POS system into a store, a POS terminal (cash register, cash register,
When installing the host computer, it is necessary to install the communication cables on the ceiling and walls according to the layout of the product shelves in the store, etc. It is necessary to include it. Also, when changing the layout of the store or adding POS terminals,
There is a constraint that the existing wiring is constrained and the degree of freedom is small, and that the construction is limited to the regular holidays of the store. Further, there is a restriction that a stand-alone POS terminal must be placed when a special sales floor is installed outside the store. And the wiring inside the store makes it unsightly.

Therefore, today, a wireless communication system using electromagnetic waves such as radio waves and infrared rays has been proposed and put to practical use in LAN systems. In a wireless communication system using such an electromagnetic wave, as shown in FIG. 41, a wireless communication control module 51 is installed on a ceiling 52 or the like in order to avoid an object that may cause radio interference and to reach a communication system. Are configured. An example of this is
There is a system (trade name "Altea Plus") manufactured by Motorola, Inc. of the United States, which connects a server to a wireless communication control module called CM (control module) and a wireless communication module called UM (user module). This is a wireless LAN system in which one or several other terminals are connected and communication is performed between the server and other terminals via the CM and UM.

Further, today, as shown in FIG. 42, a device 5 such as a printer is remotely used from an information processing device 53 such as a personal computer by utilizing infrared rays or radio waves.
A small-scale wireless system that controls 4 is also constructed.

In any case, in a system using wireless communication, a direct one-to-one relationship is maintained between a transmitting station and a receiving station, and electromagnetic waves are directly transmitted between both stations. I need to put it.

As shown in FIG. 43, a general packet used for wireless communication has a structure in which a terminal ID (identification number) indicating a transmission source and a reception destination is added in front of data, and the transmission source terminal is Own terminal ID and destination terminal ID
When a packet that has been set is sent, the terminal that receives the packet compares its own terminal ID with the destination terminal ID set in the packet, and if they match, recognize that the packet is addressed to itself. The packet receiving process is performed.

[0009]

As described above, in a wireless communication system using electromagnetic waves such as radio waves and infrared rays, it is necessary to consider the arrangement of terminals so that the electromagnetic waves can be received. In particular, when infrared rays are used, since the straightness is strong, a space with good visibility and no obstacles is required. The same can be said when radio waves having a relatively high frequency are used, and a space with few obstacles is required.

Further, in the case of a wireless communication system using electromagnetic waves, there is a limit to the reach of electromagnetic waves even without obstacles. For example, in the case of a low power radio that uses an electric wave of 400 MHz band with an output of about 10 mW, it is generally 50 m to 100 m.
The communication distance is about the same. Further, in the case of a wireless communication system, there is a problem of confidentiality. Therefore, a spread spectrum wireless communication system capable of wireless communication with relatively low output and excellent confidentiality has also been considered.

The radio wave reachable distance in the radio communication system using such a spread spectrum system is about 100 m in radius. In the case of an even wider store that exceeds the radio wave reachable distance, or when the backyard is a corner of the store and a terminal is on a diagonal line, the radio wave reachable distance is insufficient and it is impossible to cover the entire store.

As shown in FIG. 44, considering the case where four terminals A to D are installed in a closed area having a size exceeding the radio wave reach distance, in the conventional one-to-one communication,
The communication between the terminal A and the terminals B and C and the communication between the terminal D and the terminals B and C are possible, but the communication between the terminal A and the terminal D is due to the limitation of the communication distance. The communication between the terminal B and the terminal C may be disabled due to obstacles.

In this case, there is also a method of expanding the communication area by separately mounting a dedicated radio relay device on the ceiling or the like, but it is necessary to consider the terminal such as whether all the terminals can be seen from the radio relay device. At the same time, there is a problem that the cost of the radio relay device itself and installation work thereof are required.

Further, wireless communication is apt to be affected by temporal and spatial environmental changes. For example, in a merchandise store, movements of people (customers, clerk), quantity of merchandise (displayed products are taken out by shoppers, clerk replenished products,
(They change over time), and inventory changes depending on the season and time, and the movement of barriers such as shelves in the store due to the sale of special items, etc. will be redesigned (partial). (Including the case of everything from inside the store). If the communication environment changes in this way, it is naturally possible that even terminals that were initially able to communicate could become unable to communicate due to radio interference, so even if the above-mentioned dedicated radio relay device is used. In that case, it is necessary to move the installation position of the radio relay device to an appropriate position or add another radio relay device.

Further, when a dedicated radio relay device is used, if the radio relay device fails, a plurality of terminals cannot communicate in the system and the entire system is greatly affected. , In some cases, the system goes down. Therefore, in order to avoid such a situation, it is necessary to prepare a dedicated alternative machine, which incurs costs.

The present invention has been made in view of the above, and an object thereof is to expand a communication area without constructing a dedicated radio relay device when constructing a wireless LAN communication system in a closed area. It is to provide a wireless LAN communication system capable of performing the above.

[0017]

A wireless LAN communication system according to the invention of claim 1 comprises a plurality of terminals equipped with wireless communication means, and in order to solve the above problems, the following means are provided. Is being taken.

That is, each terminal in the system transmits a response request signal from its own terminal to each of the other terminals before entering the normal communication mode, and whether a response signal is returned from the terminal which transmitted the response request signal. Depending on whether or not direct communication is possible, it is provided with a direct communication availability checking means for checking each individual terminal, and the results of the above-mentioned investigations performed by each terminal in the system are combined into one and belong to the system. A communication correlation table indicating whether or not direct communication between all terminals is possible is created in the system, and the terminal that can be the starting station that is the source of data communicates with the terminal that cannot directly communicate with its own terminal. A relay station candidate terminal selecting means for selecting at least one relay station candidate terminal that can be a relay station necessary for performing the communication based on the above-mentioned communication correlation table is provided, and direct communication with the self terminal is possible. When communicating with another terminal, one of the relay station candidate terminals selected by the relay station candidate terminal selecting means is selected as a relay station, and a transfer request packet indicating the transfer destination is sent to that terminal. Each terminal in the system determines whether or not the received packet is a transfer request packet, and when a transfer request packet is received, transfers the packet to the transfer destination indicated in the packet. It is characterized by having means.

In the wireless LAN communication system according to the second aspect of the present invention, in the configuration of the first aspect of the invention, the header portion of the packet used for communication within the system is the terminal of the terminal that actually receives the packet. A destination field in which the ID is set, a source field in which the terminal ID of the terminal that actually sends the packet is set, and a terminal ID of the starting station that is the source of the data included in the packet are set. A starting station field, a final station field in which a terminal ID of the final station that finally receives the data contained in the packet is set, and a terminal of at least one relay station indicating a relay route on the way from the initial station to the final station The packet relay means is composed of a relay information field in which an ID can be set. When the IDs do not match, it is determined that the packet is a transfer request packet, the terminal ID of the transfer destination is acquired based on the information in the relay information field of the packet, and the packet is transferred to the transfer destination. It is characterized by that.

In the wireless LAN communication system according to the invention of claim 3, in the configuration of the invention of claim 1, the header part of the packet used for communication in the system is a terminal of a terminal which actually receives the packet. A destination field in which the ID is set, a source field in which the terminal ID of the terminal that actually sends the packet is set, and a terminal ID of the starting station that is the source of the data included in the packet are set. The initial station field and the final station field in which the terminal ID of the final station that finally receives the data contained in the packet are set are included. The packet relay means includes a destination field and a final station field of the received packet. If the terminal ID of the packet does not match that of the packet, it is determined that the packet is a transfer request packet, and Gets the end ID as the terminal ID of the transfer destination, is characterized by forwarding the packet to its destination.

In the wireless LAN communication system according to the invention of claim 4, in the configuration of the invention of claim 1, the terminal which can be the originating station which is the source of the data is the relay selected by the relay station candidate terminal selecting means. Each time a transfer request packet is transmitted to a station candidate terminal, the presence or absence of a communication error is determined by whether or not a reception completion signal is returned from the relay station candidate terminal, and the number of times of communication with each relay station candidate terminal and A communication result recording means for recording the number of occurrences of communication errors for each individual relay station candidate terminal, and when there are a plurality of relay station candidate terminals when communicating with a terminal that cannot directly communicate with the own terminal, Select the relay station candidate terminal that has the lowest communication error occurrence rate as the relay station by obtaining the communication error occurrence rate from the number of times of communication and the number of communication errors of those relay station candidate terminals. It is characterized in that it comprises a stage.

In the wireless LAN communication system according to a fifth aspect of the present invention, in the configuration of the fourth aspect of the invention, the terminal that can be the starting station that is the source of data is a relay station for each relay station candidate terminal. Is provided with weighting factor setting means capable of presetting a weighting factor representing the difficulty of selection, and the relay station selecting means selects one relay station candidate terminal as a relay station from a plurality of relay station candidate terminals. It is characterized in that the communication error occurrence rates of these relay station candidate terminals are corrected by weighting factors, and the corrected communication error occurrence rates of the relay station candidate terminals are compared to select a relay station.

A wireless LAN communication system according to the invention of claim 6 is the configuration of the invention of claim 4 or 5,
A terminal that can be the starting station that is the source of data is used when there are multiple relay routes through multiple relay station candidate terminals that can be selected as communication routes with terminals that cannot directly communicate with the own terminal. A fixed relay station setting means capable of previously setting a specific relay station candidate terminal among the plurality of relay station candidate terminals as a fixed relay station is provided, and the relay station selecting means is one of the plurality of relay station candidate terminals. When a fixed relay station is set when selecting one relay station candidate terminal as a relay station, only the terminal set as the fixed relay station is selected as the relay station.

[0024]

According to the structure of the invention of claim 1, each terminal in the system can directly communicate with each other while transmitting a response request signal from its own terminal to each of the other terminals before entering the normal communication mode. A communication indicating whether or not direct communication is possible between all the terminals belonging to the system by checking whether or not it is possible for each individual terminal, and finally combining the results of the above investigation conducted by each terminal in the system into one. Build a correlation table in the system.

Therefore, by holding this communication correlation table, it is possible to grasp the mutual relation of the communication status between the terminals regardless of the positional relation of the terminals in the system. This communication correlation table will be held by the terminal that can be the originating station that is the source of the data (for example, the master machine in the POS system) (if all terminals in the system can be the originating station, all terminals are Holds the communication correlation table).

The terminal which can be the starting station is
A relay station candidate terminal that can be a relay station necessary for communicating with a terminal that cannot directly communicate with its own terminal is selected based on the above communication correlation table.
When the initiating station communicates with a terminal that cannot directly communicate with its own terminal, one of the relay station candidate terminals is selected as a relay station and a transfer request packet indicating the transfer destination is sent to that terminal. Send.

Each terminal in the system has a relay station function, determines whether the received packet is a transfer request packet, and is indicated in the packet when the transfer request packet is received. The packet is forwarded to the forwarding destination.

In this way, by utilizing the wireless communication function of the terminal itself in the system and using the terminal itself in the system as a relay station, the communication area is expanded without the need for a dedicated radio wave relay device. be able to. Also, when relay is required, the terminal that is the starting station can easily select a relay station candidate terminal based on the communication correlation table.

According to the configuration of the invention of claim 2, in the header portion of the packet, in addition to the fields of the transmission destination and the transmission source that physically show a one-to-one communication relationship, there is the transmission source of the data. A field of relay information indicating a starting station, a final station that finally receives data, and a relay route is provided. At least one terminal ID indicating a relay route can be set in the relay information field. Therefore, depending on the setting of this relay information field, one-stage relay or multi-stage relay (relay via multiple relay stations in series)
Can be specified.

The terminal receiving the packet having the above configuration
By comparing the terminal IDs in the destination field and the last station field, if the terminal IDs in both fields match, it is possible to determine that the packet is addressed to itself, and if it does not match, it is a transfer request packet. Therefore, it is not necessary to set the command indicating the transfer request.

When the terminal receives the transfer request packet, the terminal ID of the transfer destination is acquired based on the information in the relay information field of the packet, and the packet is transferred to the transfer destination. As a result, the information data transmitted from the starting station sequentially propagates through the relay stations set in the packet and reaches the final station.

Therefore, the communication area can be remarkably expanded while using a large number of relay stations, and a relay route avoiding complicated radio wave obstacles can be secured.

According to the above configuration of the invention of claim 3, in the header portion of the packet, in addition to the fields of the transmission destination and the transmission source that physically show a one-to-one communication relationship, there is the transmission source of the data. Although there is a starting station and a final station that finally receives data, the relay information field is not present. When this packet is used, only one stage of relay can be performed as follows.

The terminal receiving the packet having the above configuration
The terminal IDs in the destination field and the last station field are compared to determine whether the packet is a self-addressed packet or a transfer request packet. If the terminal IDs in the above two fields do not match, it can be determined that the packet is a transfer request packet (in other words, the self terminal is the relay station). In this case, the terminal in the last station field of the packet can be determined. The ID is acquired as the terminal ID of the transfer destination. That is, when the self-terminal serves as a relay station, it is clear that the transfer destination becomes the last station if the relay has only one stage. Then, the terminal which is the relay station transfers the packet to the final station which is the transfer destination.

As described above, when the system is operated by limiting the relay to only one stage, each terminal is configured to perform the packet relay processing as described above, so that the relay information field is not necessary and economical. A packet structure is possible and efficient communication is possible. Further, with the simplification of the packet structure, the packet relay logic in each terminal is also simplified.

According to the configuration of the invention of claim 4, the originating station records the communication result relating to communication failure and success every time the transfer request packet is transmitted to the relay station candidate terminal,
This is used as a criterion for selecting a relay station. That is, the originating station, each time it transmits a transfer request packet to a relay station candidate terminal, determines whether or not there is a communication error depending on whether a reception completion signal is returned from the relay station candidate terminal, and each relay station candidate terminal The number of times of communication with and the number of times of occurrence of communication errors are recorded for each relay station candidate terminal. Then, when there are a plurality of relay station candidate terminals, the communication error occurrence rate is obtained from the number of times of communication and the number of communication errors of those relay station candidate terminals, and the terminal having the lowest communication error occurrence rate and having the best communication state is relayed. Select as a station.

As described above, the communication environment changes temporally and spatially with the increase / decrease / position change of radio wave obstacles.
If there is a relay station with poor communication, that portion becomes a bottleneck, leading to a decrease in communication efficiency, but the relay station with poor communication is not constant due to changes in the communication environment. However,
According to the invention of this claim, the learning function corresponding to the change of the communication environment is provided as described above, and the optimum relay station can be always selected from the occurrence rate of the communication error.

According to the configuration of the invention of claim 5, the terminal that can be the starting station is provided with a function of setting a weighting factor indicating the difficulty of being selected as a relay station for each relay station candidate terminal. Has been. That is, the user can weight each relay station candidate terminal as a degree of involvement in communication. The weighting coefficient set for each relay station candidate terminal works as a correction coefficient for correcting the above-mentioned communication error occurrence rate.

As a result, in a terminal that is frequently used for processing other than communication, it becomes more difficult for the terminal to become a relay station than other relay station candidates due to weighting, and the original processing capacity of the terminal is not reduced by the relay communication processing. can do.

According to the configuration of the invention of claim 6, when the terminal which can be the originating station has a plurality of relay routes through a plurality of relay station candidate terminals, the plurality of relay station candidate terminals are It has a function of setting a specific relay station candidate terminal in advance as a fixed relay station. When the fixed relay station is set, only the terminal set as the fixed relay station is selected as the relay station regardless of the communication error occurrence rate.

That is, it may be troublesome that the relay station fluctuates too much due to the learning function of the invention of claim 4 or 5, and the user's intention is prioritized over the change of the communication environment, and the relay station candidate is selected. You can select a fixed relay station from.

Thus, when a specific terminal is disconnected from the system for maintenance or the like, if the relay station is fixedly designated and then the specific terminal is disconnected from the system, communication efficiency is affected. Without affecting
There is no hindrance to the operation of the system.

[0043]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention is shown in FIGS.
The explanation is based on the following.

This embodiment shows an example in which the wireless LAN communication system of the present invention is applied to a POS system. The POS system includes a plurality of POSs equipped with wireless communication means for performing wireless communication using electromagnetic waves as a communication medium in a store which is a closed area.
A terminal is installed, and one of the POS terminals is a master machine,
This is a system in which other POS terminals are used as satellite machines, and input information such as cash registration information in each satellite machine is centrally managed by the master machine. In the POS system according to this embodiment, as will be described later, each POS terminal belonging to the system has a packet relay station function, so that the communication area can be expanded without using a dedicated relay device.

An external view of the POS terminal is shown in FIG. This POS terminal includes a POS keyboard 20 having a key group such as a product allocation key, a department key, a function key, and a numeric key, a display section 21 for displaying a screen for an operator's operation, and reading and writing information to and from a magnetic card. A magnetic card reader (MCR) 22, a line display 23 for displaying the unit price, total amount, change amount, etc. of a product to a customer, a POS printer 24 for printing on journal paper or receipt paper, An operation key 25 for switching the POS terminal to an operable mode or an inoperable mode, and a bar code reader (not shown) are provided.

FIG. 6 is a block diagram showing the internal structure of the POS terminal. This POS terminal has a CPU (Ce
ntral Processing Unit: Central processing unit 1 and R
OM (Read Only Memory) 2, RAM (Random Access)
Memory) 3, FD (floppy disk) controller 4, HD (hard disk) controller 5, screen controller 6, POS keyboard controller 7, POS
Printer controller 8, line display controller 9, bar code reader controller 10, magnetic card reader controller 11, drawer controller 12,
And a controller 13 for communication control, which are mutually connected by a system bus.

The CPU 1 executes programs, performs data processing, and performs data input / output processing such as control of connected equipment. The ROM 2 is an IPL (Initial Program Loader), which controls the input / output of the basic system in addition to the boot process of the program (the first program for the system startup and the minimum program process).
It stores an IOS program, CG (character pattern generator) data for displaying, and a simple test program at startup. The RAM 3 is a writable memory in which the system program, application program, device control program, etc. read from the hard disk are stored. The FD controller 4 and the HD controller 5 perform file control of programs, data and the like for floppy disks and hard disks as external storage devices. The screen controller 6 controls the display of the display unit 21 of FIG. 5 based on the operation of the operator. The POS keyboard controller 7 controls input to the POS keyboard 20 shown in FIG. The POS printer controller 8
Performs print control for the POS printer 24 of FIG. The line display controller 9 controls the display of the line display 23 of FIG. 5 based on the operation of the operator. Bar code reader controller 1
0 controls the input to the bar code reader and fetches the data read by the bar code reader into the system bus. The magnetic card reader controller 11 performs input / output control with respect to the magnetic card reader 22 of FIG.
While the data read by the magnetic card reader 22 is taken into the system bus, the data is recorded on the magnetic card when the card is issued. The drawer controller 12 controls the drawer for money transfer. The communication control controller 13 controls communication with another POS terminal by wireless (a general wireless system such as spread spectrum wireless). The communication control controller 13 is connected to an antenna unit 14 that emits and detects electromagnetic waves based on communication.

With the above-described structure, the POS terminal operates, and the communication control controller 1 in this is operated.
3 and the antenna unit 14 constitute a wireless communication system for transmitting / receiving data to / from another POS terminal.

The POS terminal serving as a master machine (hereinafter simply referred to as a master machine) and the POS terminal serving as a satellite machine (hereinafter simply referred to as a satellite machine) have the same basic configuration as described above. The master machine differs from the satellite machine in that the CPU 1 of the master machine has a centralized management function for all satellite machines.

Next, a procedure for setting up a plurality of the above POS terminals in the closed area and starting up the POS system will be described.

First, the operator operates the master machine to operate the terminal IDs (IDENTIFICAT) of all satellite machines in the system.
ION: Register the identifier). The terminal ID is an identifier for uniquely identifying each terminal in the system, and is also called a terminal number or a terminal address. That is, the POS system is constructed by the POS terminals whose terminal IDs are registered in the master machine, and only the POS terminals registered therein are the object of communication. In addition, the terminal ID of the own machine is registered in advance in the master machine and each satellite machine. When the registration operation is performed by the operator, the master machine creates and saves the terminal list shown in FIG. In the terminal list, the first item is the terminal I of the master unit itself.
D, the second and subsequent items store the terminal IDs of the satellite machines in the order of registration. Here, a 1-byte storage area is allocated as an area for storing each terminal ID, but if the number of bits of the terminal ID is larger than that, if a storage area of several bytes is used to store each terminal ID, There is also.

Then, with each POS terminal placed at a predetermined position in the store, each POS terminal is set to the communication correlation table creation mode. When this mode is entered, each POS terminal sequentially checks the availability of communication with other POS terminals to create the communication availability list of FIG. 3, and collects the communication availability list created by each POS terminal, and finally Specifically, the communication correlation table of FIG. 1 showing whether communication is possible between all POS terminals belonging to the system is created in the system.

FIG. 10 shows the structure of a packet used for communication in this communication correlation table creation mode. This communication correlation table creating packet is composed of a transmission destination ID, a transmission source ID, a starting station ID, a final station ID, a command, and data. The following commands are prepared.

# 01: Communication availability list creation request command # 02: Communication availability list creation end command (to master machine) # 03: Response request command # 04: Response command # 05: Transfer request command # 06: Creation sequence end request Command (To Satellite Device) Next, the operation of the master device in the communication correlation table creation mode will be described with reference to the flowchart shown in FIG.

When the mode is entered, the master machine fetches the terminal list previously registered in FIG. 2 (S1). next,
The master machine sequentially asks each satellite machine whether or not communication is possible, and the result is put together to shift to a routine for creating a communication possibility list shown in FIG. 3 (S2).

Here, the communication availability list creating routine of S2 will be described in detail with reference to the flowchart of FIG. The master machine sends out a packet (response request packet) requesting a response to each satellite machine and individually inquires whether communication is possible (S21, S22). For the satellite machines that have received a response within a predetermined time (S23). ), Data (for example, “1”) indicating communication availability is recorded in the field corresponding to the satellite machine in the communication availability list, and for satellite machines that have timed out without a response within a predetermined time (S25). Data (for example, "0") indicating that communication is impossible is recorded in the field corresponding to the satellite machine in the communication availability list (S26). When the above communication availability check is completed for all the satellite machines stored in the terminal list of FIG. 2 and the creation of the communication availability list is completed (YES in S21), the process returns to the main routine of FIG.

After the completion of the communication permission / prohibition list creation routine, it is determined whether or not there is a satellite machine for which a communication permission / prohibition list is to be generated (S3). Normally, each satellite machine is made to create the same communication availability list as described above, but this is not necessary in the following cases. In other words, in step S2 above, access from the master machine causes all registered POS
If the terminal is accessible, the relay is not required for communication between the master unit and the satellite unit, so the subsequent processing is not required (However, if communication between satellite units is required, continue). Also, the PO in the system
Even when there are a total of two S terminals, the master machine and one satellite machine, the subsequent processing is unnecessary.

If YES in S3, the master machine selects one satellite machine that can communicate with its own terminal based on the created communication availability list, and sends out a communication availability list creation request packet to that satellite machine (( S
4). At this time, when there are a plurality of satellites that can communicate with the self terminal, one is selected according to the registration order of the terminal list in FIG. 2 (note that there is no particular selection criterion in this case, any one can be selected. Good).

At this time, the terminal list of FIG. 2, the terminal link table (see FIG. 4), and the communication correlation table (see FIG. 1) are added to the communication permission / inhibition list creation request packet transmitted by the master unit as attached data. Here, the terminal link table is used by the terminal transmitting the packet to sequentially record the route from the master machine to which the communication availability list creation request packet reaches the current receiving terminal. Then, only the terminal ID of the master itself is set in the first field of the terminal link table and added to the packet. Further, the communication correlation table added to the communication permission list creation request packet here is a copy of the communication permission list created by the master machine as it is in the column of its own terminal in the communication correlation table.

Upon receiving the communication availability list creation request packet from the master machine, the satellite machine starts to create the communication availability list centered on itself, as will be described later. On the other hand, the master machine then waits for packet reception from the satellite machine (S5). When the master device receives the packet from the satellite device (YES in S6), the command included in the packet is analyzed (S7), and the subsequent processing is divided according to the command classification.

The type of packet command sent by the satellite machine to the master machine depends on the processing on the satellite machine side. Here, the operation of the satellite machine in the communication correlation table creation mode will be described with reference to the flowchart shown in FIG.

When the communication correlation table creation mode is entered, each satellite machine enters a packet reception waiting state (S3).
1). When a satellite machine receives a packet from another POS terminal (YES in S32), the command included in the packet is analyzed (S33), and the subsequent processing is divided according to the command classification.

If a response request packet is received from the master machine or the satellite machine (the operation of the satellite machine will be described later) executing the above-mentioned communication permission / inhibition list creation routine, after the judgment of S33, the response request packet The response packet is returned to the source master device or satellite device (S42).

If the communication availability list creation request command is set in the received packet (that is, if the received packet is the communication availability list creation request packet), the flow goes to the communication availability list creation routine (S34). still,
As described above, the terminal availability list (see FIG. 2), the terminal link table (see FIG. 4), and the communication correlation table (see FIG. 1) are added to the contact availability list creation request packet. This communication availability list creation routine is similar to the above-described routine shown in the flowchart of FIG. 8, and the satellite machine determines whether or not it is possible to sequentially communicate with other satellite machines centering on itself according to the order of the terminal list. Inquiries are made and the communication availability list (see FIG. 3) is created by summarizing these results. However, if you check the communication correlation table added to the received packet and judge that the communication availability with your machine has already been confirmed from the table, the communication availability is checked, and only the terminals that have not communicated are checked. The process after S22 of the flowchart of FIG. 8 is performed. For example, the satellite machine that has received the communication availability list creation request packet transmitted from the master machine does not communicate with the master machine that has already communicated once, but communicates with other satellite machines.
That is, if one value is determined in the communication correlation table in FIG. 1, the value in the column symmetrical to the above value is also determined with the diagonal line to the lower right as the axis of symmetry, so that any value above or below the diagonal line is determined. If so, the communication correlation table is completed.
The value on the diagonal line is always "1" because it communicates with itself.

After S34, the satellite machine determines whether or not there is still a terminal for which a communication availability list is to be created from the terminal list and communication correlation table added to the received packet (S35). If so, it is determined whether or not there is a terminal capable of communicating with its own terminal among the terminals for which the communication availability list is to be created based on the communication availability list created previously (S36).

When there is a terminal for which a communication permission / prohibition list capable of communicating with the self-device exists (YES at S35 and S36), a communication permission / prohibition list preparation request packet is sent to that terminal (S37). . At this time, when there are a plurality of terminals to which the packet should be transmitted, one terminal is selected according to the registration order of the terminal list.

At this time, the communication permission / prohibition list creation request packet sent by the satellite device includes the terminal list, the terminal link table (the received terminal link table added with the terminal ID of its own), and the communication correlation as described above. The table (which is created by reflecting the created communication availability list in the field of the own device on the received communication correlation table) is added as attached data.

The satellite machine that has transmitted the communication permission / inhibition list creation request packet then returns to S31 and waits for packet reception, and another satellite machine that has received the packet will create the communication permission / inhibition list in the same manner as above. .

On the other hand, although there is a terminal for which a contact availability list is to be created (YE at S35)
S) If there is no terminal capable of communicating with the own device (NO in S36), the transfer request packet is sent to the terminal immediately before the own device (that is, the source of the packet) according to the received terminal link table. Is sent (S38), and then S
The process returns to step 31 to wait for packet reception. This transfer request packet is a packet in which a transfer request command is set, and like the communication availability list creation request packet, a terminal list, a terminal link table, and a communication correlation table are added as attached data.

After receiving the transfer request packet (YES in S32), the satellite machine determines whether or not there is a terminal to be transferred after the determination in S33, that is, it can communicate with itself. It is determined whether or not there is a terminal for which a communication availability list is to be created (S39).
Here, if there is a terminal to be transferred, a communication availability list creation request packet is sent to that terminal (when there are a plurality of corresponding terminals, one is selected according to the registration order of the terminal list) (S40). . On the other hand, if there is no corresponding terminal in S39, the transfer request packet is traced back to the terminal immediately before the own terminal by tracing back according to the terminal link table (S38), and then the process returns to S31 to wait for packet reception. .

As described above, while the terminal for which the communication permission / prohibition list is to be created is present in the system, the satellite communication devices transmit / receive the communication permission / prohibition list creation request packet or the transfer request packet to each other in the system. Create a communication correlation table. Here, a case where a transfer request packet is sent from a certain satellite machine to the master machine (S38) will be described by returning to the flowchart showing the processing of the master machine in FIG.

The transfer request packet is sent from the satellite machine to the master machine in the above-described manner, even though the terminal for which the communication availability list is to be created remains in the system, such terminal does not exist. This is the case when it was not possible to communicate with.

After receiving the transfer request packet (YES in S6), the master machine, after the judgment in S7, still has a terminal capable of communicating with itself among the terminals for which the communication availability list should be prepared. It is determined whether or not (S
8). Here, if there is such a transferable terminal, the master machine is the terminal (when there are a plurality of corresponding terminals, one is selected according to the registration order of the terminal list).
To the communication permission list creation request packet (S
4) Then, it waits for packet reception (S5). The satellite machine that received the communication availability list creation request packet
The communication availability list will be created in the same manner as above.

On the other hand, when there is no terminal capable of communicating with the master machine even though there is a terminal for which a communication availability list is to be created (NO in S8),
There exists a so-called hidden terminal that cannot communicate with any POS terminal in the system, and the master machine prompts the operator by displaying the hidden terminal on the display unit 21 of FIG. 5 or by printing it on the POS printer 24. Notification processing for notifying is performed (S9). After this, the master machine is set to S1 which will be described later.
The satellite machine that can be relayed is selected from the communication correlation table after shifting to 0.

Now, the processing on the satellite machine side will be described again. As described above, each satellite machine creates the communication correlation table in the system while propagating the communication availability list creation request packet or the transfer request packet. Here, after a certain satellite machine finishes the communication permission / prohibition list generation routine of S34 of FIG. 9, if it is determined in S35 that these terminals for which the communication permission / prohibition list is to be generated do not remain in the system, the communication correlation is determined. The creation of the table is regarded as completed, and a communication correlation table creation completion packet with the completed communication correlation table added as attached data is returned to the master unit (S4).
1). As the determination in S35, it is determined that there is no terminal in the system for which a communication availability list is to be created because only one terminal has not been created in the communication availability list in the system. This is because the last remaining terminal must have been accessed from all other POS terminals at least once, and it is not necessary to create a communication permission / prohibition list.

When the master machine receives the above-mentioned communication correlation table creation end packet or after S9, based on the communication correlation table finally obtained, the master machine selects a satellite machine as a relay station candidate (S10). ).
By this processing, a satellite registration list (FIG. 11), a relay station candidate list (FIG. 12), and a multistage relay station list (FIG. 13) described later are created.

After that, the master machine transmits a communication correlation table creation mode end packet to all satellite machines to notify the end of the mode (S11). At this time, the master machine itself also ends the communication correlation table creation mode, and then shifts to the communication mode. Note that direct communication cannot be performed from the master unit (that is, relay is required).
To the satellite machine, a relay station is designated by a method described later, and a communication correlation table creation mode end packet is transmitted.

Upon receiving the communication correlation table creation mode end packet (YES in S32 of FIG. 9), each satellite machine performs the communication correlation table creation mode end processing after the determination in S33 (S43), and then performs communication. Switch to mode.

In this embodiment, the CPU that executes the program of the communication availability list creation routine shown in FIG.
1, the communication control controller 13 that performs communication control based on the control of the CPU 1, and the antenna unit 14 constitute a direct communication availability checking unit described in the claims.

Here, the satellite registration list (FIG. 11), the relay station candidate list (FIG. 12), and the multistage relay station list (based on the communication correlation table created in the system during the communication correlation table creation mode). The process (S10 of FIG. 7) of the master machine that creates FIG. 13) will be described in detail.

The satellite registration list of FIG. 11 is created based on the terminal list of FIG. 2, and has a structure in which a flag is added to the terminal ID of each satellite machine in the terminal list. This flag indicates whether it is possible to directly communicate with the master unit or whether relay is required, and when relay is required, it indicates the table number of the relay station candidate list or the table number of the multistage relay station list that lists the relay station candidates. It is a thing. Specifically, "0" is set as a flag for the satellite machine that can directly communicate with the master machine.
Further, when communication with the master unit requires relay via another satellite unit, an identification number (table number) other than “0” for identifying each table of the relay station candidate list or each table of the multistage relay station list ) Is set as a flag. If there is a hidden terminal, a unique flag is set for that terminal (or that terminal may be deleted from the satellite registration list).

The relay station candidate list of FIG. 12 is a list of relay stations for satellite machines capable of communicating with the master machine through only one stage of relay, and is a table set as a flag of the satellite registration list. It is composed of a plurality of first to nth tables corresponding to numbers. Each table of the relay station candidate list is composed of a fixed relay station information field and first to nth relay station information fields. In addition, each of the above information fields includes a flag, a relay station ID, a communication count, an error count (communication error count), and weight information. For a satellite machine that can communicate with the master machine by relaying only one stage,
When there are a plurality of POS terminals that can be relay stations, those terminal IDs are set in the area of the relay station ID in the first to nth relay station information fields of the corresponding table.

The terminal ID of the relay station designated by the operator is set in the area of the terminal ID in the fixed relay station information field as described later. Further, as the information on the number of communications and the number of errors in each information field, an initial value (0) is set before the communication is started in the system. Further, the weight information in each information field can be designated by the operator as will be described later. The flag added to the head of each information field indicates whether or not the information field is used. The flag of the used field is “1” and the flag of the unused field is "0"
Is set to

The multi-stage relay station list of FIG. 13 is a list of relay stations for satellite machines capable of communicating with the master machine via multi-stage relay, and is a table number set as a flag of the satellite registration list. Corresponding to the (n + 1) th, (n + 2) th, ... Each table of this multi-stage relay station list includes a first-stage relay station information field, a second-stage relay station information field,
…. Each of the above information fields includes a flag indicating whether the field is used or not used and information on the relay station ID.

The one-step relay pattern between the master machine and each satellite machine is roughly classified into a simple type as shown in FIG. 14 and a multi-path type as shown in FIG.
In the drawings, reference numeral M is a master machine, S is a satellite machine (a terminal to be communicated with the master machine), and C is a relay station (the same applies to FIGS. 16 and 17 described later).

The above simple type is, for example, as shown in FIG. 18, one specific relay capable of communicating with both the master machine M and the satellite machine S ₂ which cannot directly communicate due to a short communication distance. This is the case where a station (here, satellite machine S ₁ ) exists. As a modification, there is a multi-branch type shown in (a) or (b) of FIG. 16, but in the relationship between the master machine and the satellite machine to be communicated, only one specific relay station exists. It can be understood as a simple type composite form of FIG.

In the multi-path type, as shown in FIG. 19, for example, there are a plurality of relay stations capable of communicating with both the master machine M and the satellite machine S ₃ which cannot directly communicate due to a short communication distance. (Here satellite machines S ₁ and S ₂ )
However, this is the case where there are multiple relay routes.

Further, as a relay pattern between the master machine and each satellite machine, there is also a multi-stage type as shown in FIG. For example, as shown in FIG. 20, the communication between the master unit M and the satellite unit S ₃ that direct communication can not be performed due to the communication distance shortage, a plurality of relay stations performing serially relay (here This is the case when satellite machines S ₁ and S ₂ ) are required.

In an actual wireless communication system, these relay patterns are combined to form various relay routes, using the relay patterns as described above as basic patterns. It should be noted that the communication distance of a typical POS terminal and the size of the closed area (store scale)
Considering the above, the multi-path type relay pattern of FIG. 15 can be considered as a typical general pattern.

When selecting satellite stations as relay station candidates based on the communication correlation table, it is possible to discover which satellite machine can be a relay station of which relay pattern by looking at the table as it is. By applying an appropriate logical operation to the communication correlation table, the relay station can be found more easily in terms of data processing. The procedure for discovering a relay station will be described below with some examples.

First, the POS terminals A to A as shown in FIG.
Consider a system having a multi-path type relay pattern consisting of F (POS terminal A is a master machine and others are satellite machines). The communication correlation table created in this system is shown in FIG. From the master device A column of this communication correlation table, it can be seen that the master device A cannot directly communicate with the satellite devices E and F. However, the relay station for enabling communication with the satellite devices E and F is as follows. It can be easily found by taking the logical product in this way.

That is, the logical product table of FIG. 23 based on the master machine A derived from the above communication correlation table is created. More specifically, in FIG. 23, the communication result “111100” of the master machine A and the satellite machine B are shown in FIG.
The result "111100" of the logical product of the same columns with the communication result "111100" of the master machine A is written in the column of the satellite machine B, and the communication result of the master machine A and the communication of the satellite machines C to F are similarly performed. The result of calculating the logical product of the same columns with the result is written in the column of each satellite machine. The logical product table based on this master machine A is
Each of the satellite machines B to F and the master machine A represents a satellite machine that can directly communicate with each other (that is, a common terminal with the master machine A of each of the satellite machines B to F). This allows
It can be easily understood that the satellite machines C and D can serve as relay stations for communication between the satellite machine E and the master machine A, which cannot directly communicate with the master machine A. Further, it is similarly understood that the satellite machine C and the satellite machine D can be relay stations for the communication between the satellite machine F and the master machine A.

The relay station candidates obtained as described above are reflected in the relay station candidate list (FIG. 12). For example, in the above case, the satellite machine E in the satellite registration list of FIG.
Set a flag is added to the terminal ID "n _1", the n ₁ first relay station information field to the terminal ID of the satellite unit C of the table in the relay station candidate list of FIG. 12, the second relay station information field The terminal ID of the satellite machine D is set to.

In the above case, the relay station candidates for the satellite machine F are exactly the same as the relay station candidates for the satellite machine E, so they are added to the terminal ID of the satellite machine F in the satellite registration list of FIG. The flag can be set to the same “n ₁ ” as the satellite machine E, and the same table of the relay station candidate list can be used together.

Next, POS terminals A to A as shown in FIG.
Consider a system having a multi-branching type relay pattern, which is composed of H (POS terminal A is a master machine and others are satellite machines). The communication correlation table created in this system is shown in FIG. Further, a logical product table based on the master machine A derived from this communication correlation table is shown in FIG.
6 is shown.

First, from the column of the master machine A in the communication correlation table of FIG. 25, the master machine A can directly communicate with the satellite machines B, C, F, but cannot directly communicate with the satellite machines D, E, G, H. I understand. From the logical product table based on the master machine A in FIG. 26, the satellite machines DE
The satellite station C may be a relay station for communication between the master station A and the master station A, and the satellite stations G and H and the master station A may be the relay stations.
Satellite station F can be a relay station for communication with
I understand that. Then, the relay station candidates obtained here are reflected in the relay station candidate list (FIG. 12). For example, the above case is set to both "n _2" flag to be added to the terminal ID of the satellite machine D · E satellite registration list in FIG. 11, the n ₂ relay station candidate list of FIG. 12
Satellite device C in the first relay station information field of the table
Set the terminal ID of. Further, all the flags added to the terminal IDs of the satellite machines G and H of the satellite registration list of FIG. 11 are set to “n ₃ ”, and the first relay station of the n _3rd table of the relay station candidate list of FIG. 12 is set. The terminal ID of the satellite device F is set in the information field.

In the multi-branch type relay pattern,
A relay station common to a plurality of satellite machines exists, and a group having the relay station as a key station is configured. In the above example, the satellite machines D and E are groups of satellite machines C,
The satellite machines G and H become a group of satellite machines F. By using the following method, it is possible to easily check which satellite machine belongs to which relay station group.

That is, targeting the logical product table based on the master device A of FIG. 26, the values of the respective columns of the satellite machines B, C, and F that can directly communicate with the master device A (see the logical product table of FIG. 26). Create a logical product table based on
Specifically, the logical product table of FIG. 26 is used as the calculation target, and the logical product table (FIG. 27) based on the value “11000000” in the column of satellite machine B is used, and the value “101 of the column of satellite machine C is used.
A logical product table based on 0000000 "(FIG. 28) and a logical product table based on the value" 10000100 "in the column of the satellite machine F (FIG. 29) are created.
From FIG. 7, there is no terminal belonging to the group having the satellite machine B as a relay station. From FIG. 28, the satellite machines D and E belong to the group having the satellite machine C as a relay station, and from FIG. 29, the satellite machines G and H. It is obvious that the satellite belongs to the group having the satellite machine F as a relay station.

When the table of the relay station candidate list of FIG. 12 is created, it is basically necessary to create one table for one group. Therefore, as described above, which satellite machine belongs to which relay station group. If it is known, it becomes easy to create the table.

Next, POS terminals A to A as shown in FIG.
Consider a system having a multi-stage relay pattern made up of G (POS terminal A is a master machine and others are satellite machines). A communication correlation table created in this system is shown in FIG. 32 is a logical product table based on the master machine A derived from the communication correlation table.
Shown in

First, from the column of the master machine A in the communication correlation table of FIG. 31, the master machine A can directly communicate with the satellite machines B / C, but cannot directly communicate with the satellite machines D / E / F / G. Recognize. Then, the master machine A in FIG.
From the logical product table based on the above, it is understood that the satellite machine C can be a relay station for communication between the satellite machines DE and E and the master machine A. Then, the relay station candidates obtained here are reflected in the relay station candidate list (FIG. 12). Further, it can be seen from FIG. 32 that there is no terminal that can be a relay station of only one stage in the communication between the satellite machines FG and the master machine A. That is, it is understood that multistage relay is required for the satellite machines F and G.

Here, the satellite machine which can be a multi-stage relay station is B or C which can directly communicate with the master machine A. Therefore, for the communication correlation table of FIG. 31,
A logical product table is created based on the values in the columns of the satellite machines B and C (of the communication correlation table in FIG. 31). FIG.
3 shows a logical product table based on the satellite machine C (the logical product table based on the satellite machine B is omitted). From the figure, it can be seen that the satellite machine C, which is the first relay station from the master machine A, can reach the satellite machines F and G by using the satellite machine E as the second relay station. Then, the obtained plurality of relay stations connected in series are reflected in the multistage relay station list (FIG. 13).

As described above, by obtaining the logical product table with each POS terminal based on the communication source terminal, the shared POS terminal can be easily known without knowing the actual terminal arrangement.

In this embodiment, the relay station candidate terminal selecting means described in the claims is achieved by the CPU 1 which executes the program for performing the above logical operation processing based on the communication correlation table.

Next, the operation in the communication mode will be described. In this communication mode, the master machine is based on the satellite registration list (FIG. 11), relay station candidate list (FIG. 12), and multi-stage relay station list (FIG. 13) created in the above-described communication correlation table creation mode. While selecting a relay station, it communicates with a desired satellite machine.

The structure of a packet used for communication in the communication mode is shown in FIG. The packet is composed of a transmission destination, a transmission source, a starting station, a final station, and relay information (relay stations n to 1) that form an ID field (header section), and data added after the ID field. It is configured. Here, the transmission destination and the transmission source physically show a one-to-one communication relationship, and the terminal ID of the other party to which the packet is transmitted is set in the transmission destination field.
Terminal ID of the packet sending side in the destination field
Is set. The terminal ID of the sender of the information data is set in the starting station field, and the terminal ID of the receiver of the information data is set in the last station field. A terminal ID of a POS terminal used as a relay station is set in the relay information field (each field of relay stations n to 1) (maximum relay station number n). The information data transmitted from the starting station propagates from the relay station 1 to the relay station n in sequence and reaches the final station.

The packet shown in FIG. 34 is a fixed-length packet in which the maximum number of relay stations is determined. However, as shown in FIG. 35, a field indicating the number of relay stations is provided at the beginning of the relay information field and relay information is provided. The fields can also be of variable length.

When the master machine sends data to a satellite machine, whether or not direct communication with the satellite machine is possible is judged by referring to the satellite registration list (FIG. 11).
That is, the terminal ID of the desired satellite machine is searched from the satellite registration list, and the possibility of direct communication is determined from the flag added to the terminal ID. here,
When it is possible to communicate directly with the above satellite devices (flag =
0) sets the terminal ID of its own device (master device) in the field of the transmission source and the originating station in the ID field of the packet of FIG. 34 or FIG. 35, and communicates both in the fields of the transmission destination and the final station. The terminal ID of the partner satellite device is set, and the terminal ID is not set in the relay information field. Then, the packet having the data added to the ID field as described above is transmitted.

On the other hand, when it is not possible to directly communicate with the desired satellite machine (flag ≠ 0), the relay station candidate list corresponding to the flag shown in the satellite registration list (see FIG. 1).
2) Or, see the table of the multi-stage relay station list (FIG. 13) and obtain the satellite machine to be the relay station. When a plurality of relay station candidates are registered in the table of the multi-stage relay station list (FIG. 13), one of them is selected (when a fixed station is registered in the fixed relay station information field as described later, The fixed station is used as a relay station, and the optimum relay station is selected based on the communication count, error count, and weight information.)
To do. Then, the terminal ID of the own device (master device) is set in the fields of the transmission source and the originating station in the ID field of the packet of FIG. 34 or FIG. 35, and the terminal ID of the satellite device of the communication partner is set in the final station field. Set the terminal ID of the selected relay station (the first relay station in the case of multiple stages) in the destination field, and set the terminal ID of each relay station in the relay information field in the reverse order of the relay order. Set. Then, the packet in which data is added to the ID field generated in this way is transmitted.

When there are a plurality of relay station candidates,
If the transmission to the POS terminal selected from them fails (for example, due to the presence of an obstacle such as a luggage or a person near the POS terminal), another relay station candidate may be selected and selected as necessary. Send packets by route.

The packet receiving process and the operation on the relay side will be described with reference to the flowchart of FIG.

When the destination ID set in the packet received while waiting for packet reception is the terminal ID of the own device, the packet is received (S51). Then, by checking the ID field of the packet, it is judged whether or not the terminal IDs of the transmission destination field and the last station field match (S52). In-flight processing is performed (S53).

When the last station processes the packet in itself, the terminal I of the relay station is read from the relay information field of the packet.
Remove D and save. If the terminal IDs of the extracted relay stations are rearranged in the reverse order, the relay path through which the packet is propagated can be known from the final station to the master machine while moving backward from the original relay station. Therefore, when the last station needs to transmit data to the master machine, a packet is generated and transmitted in the same manner as above based on the terminal ID of the relay station that has been saved.

Further, in S52 described above, the destination ID
If the end station ID does not match the last station ID, the received packet is recognized as a relay request (transfer request) packet, and the destination ID (= terminal ID of the terminal) set in the relay information field is recognized. The next (previous) terminal ID is taken as the transfer destination terminal ID from the relay information field or the last station field (S54).

Next, a packet to be sent to the transfer destination is created. That is, the content of the destination field of the received packet is set in the source field (in other words, the terminal ID of the own device is set in the source field) (S5).
5). Further, the terminal ID of the transfer destination is set in the transmission destination field of the received packet (S56). After that, the packet is transmitted (S57), and the transfer (relay) ends.

By the way, although it is possible to expand the communication area by performing multi-stage relay, if the number of relay stages increases,
It is undeniable that communication efficiency deteriorates due to the increase in the length of the packet header. Therefore, by limiting the number of relay stages to only one and shortening the data length with a packet structure for one-station relay as shown in FIG. 37, efficient communication becomes possible.

The above-mentioned one-station relay packet has a header section consisting of the fields of destination, source, originating station, and last station, which are obtained by removing the relay information field from the packet (FIG. 34 or FIG. 35). are doing. Here, the transmission destination and the transmission source physically show a one-to-one communication relationship similarly to the above, but in this case, they are also used as the ID field of the relay station. In the destination field, the terminal ID of the other party who sends the packet is set. The terminal ID of the packet sending side is set in the destination field.
In the starting station field, the terminal ID of the sender of the information data,
In the last station field, the terminal ID of the receiver of the information data
Are set respectively.

Note that the above-mentioned one-station relay packet and the above-mentioned packet shown in FIG. 34 or 35 do not coexist in the same system. Therefore, when communication using the one-station relay packet is performed, a communication mode different from the communication mode in which multi-stage relay is possible is set in advance. Also,
In this case, since the multistage relay is not performed, it is not necessary to create the multistage relay station list (FIG. 13).

When the master machine transmits data to the satellite machine which can directly communicate by using the above-mentioned one-station relay packet, the master machine itself is set in the source field and the originating station field in the ID field of the packet of FIG. (Master machine)
The terminal ID of the satellite device of the communication partner is set in the fields of the destination and the last station while setting the terminal ID of
Send the packet with. On the other hand, if the desired satellite device cannot be directly communicated with, the terminal ID of its own device (master device) is set in the fields of the transmission source and the originating station in the ID field of the packet of FIG. Terminal ID of the other party's satellite machine
Is set, and the packet in which the terminal ID of the relay station selected from the satellite registration list is set in the destination field is transmitted.

The packet reception processing of the POS terminal and the operation on the relay side when the above-described one-station relay packet is used will be described below with reference to the flowchart of FIG.

When a packet whose destination ID set in the packet is its own terminal ID is received (S6
1) Looking at the ID field of the packet, it is judged whether or not the terminal IDs of the destination field and the last station field match (S62), and if they match, the packet is recognized as a packet addressed to itself, The process in the own machine is performed (S63). At this time, the contents of the destination field are saved. This is because, in a system that relays only one stage, the terminal set in the destination field becomes a relay station. Therefore, when this POS terminal needs to send back data to the master machine, a packet is generated and sent out in the same manner as above based on the terminal ID of the relay station that has been saved. However, if the same terminal ID is set in the fields of the transmission source and the originating station in the received packet, it can be determined that there is no relay station. In this case, it is not necessary to store the relay station ID.

In S62, the destination ID
And the last station ID do not match, the received packet is recognized as a relay request (transfer request) packet, and the terminal ID set in the last station field is acquired as the transfer destination terminal ID ( S64). Next, the contents of the destination field of the received packet are set in the source field (in other words, the terminal ID of the own device is set in the source field).
Is set) (S65). Further, the terminal ID of the transfer destination acquired earlier is set in the transmission destination field of the received packet (S66). In this case, the device is the relay station,
The transfer destination will be the final station. Then send the packet (S
67), and the transfer (relay) ends.

Considering the communication distance of the POS terminal and the size of the closed area (store scale), etc., it is generally considered that the system is often constructed with only one relay. Therefore, in this case, it is considered very effective to increase the communication efficiency by using the economical packet structure as described above.

In this embodiment, the CPU 1 executing the processing program shown in FIG. 36 or FIG.
The packet relaying means described in the claims is achieved.

By the way, as described above, the communication environment is
Due to movements of people, quantity of products, changes in store layout, etc. (that is, increase / decrease of radio wave obstruction / position change)
Change spatially. Further, in the POS terminal that performs the relay, the communication performance is degraded (the congestion level) depending on the frequency of use as the relay station. Furthermore, a situation such as a POS terminal failure may be encountered. In order to respond to changes in the communication environment including these and to always select the best relay station from among a plurality of relay station candidate terminals, it is necessary to grasp the communication status of each POS terminal. . In view of this, in this embodiment, the master machine records the communication results relating to the failure and success in communication with respect to the POS terminal that has become the relay station, and uses this as the basis for determining the relay station selection.

Further, in order to cope with the case where there are POS terminals which are not desired to be used as relay stations in the system, in the present embodiment, the relay station candidates are weighted as the degree of involvement in communication. It is possible. For example, in a POS terminal that is frequently used for processing other than communication, if the communication load due to relaying is large, the load on the CPU becomes large, and the original processing capacity of the POS terminal may decrease. Therefore, such a POS terminal is less likely to be a relay station than other relay station candidates due to weighting (excluded from the relay station candidates if necessary), and the original processing capability of the POS terminal is the relay communication processing. Can be prevented from dropping.

That is, in this embodiment, as a condition element for selecting a relay station when there are a plurality of relay station candidate terminals,
Three are given: the number of times of communication, the number of times of communication error, and a weighting coefficient (hereinafter, simply referred to as weight) in consideration of the load on the POS terminal. Next, the optimization of the relay station based on these condition elements will be described with reference to the flowchart of the packet transmission process of the master machine shown in FIG.

After generating the packet data (S71), the master machine determines the relay station, and then determines the number of communication times in the first to nth relay station information fields of the predetermined table of the relay station candidate list (FIG. 12). , The number of errors, and the weight information are used to select the optimum relay station (S72). This S7
A detailed description of the processing of No. 2 will be given later. Also, as will be described later, when a fixed station is designated in the fixed relay station information field of the relay station candidate list, the designated terminal is used as the relay station.

Next, the terminal ID of the selected relay station is set in the ID field of the packet (S73). Also, I
The required terminal ID is set in each of the other fields of the D field as described above, and the packet is transmitted (S74).

Thereafter, it is judged whether the transmission to the relay station is normal or not depending on whether or not the reception completion signal (ACK) is received from the relay station within a predetermined time (S75). The value of the number of communication times of the used relay station in the relay station candidate list (FIG. 12) is incremented by 1 (S76).

On the other hand, when the communication with the relay station cannot be normally performed (NO in S75), the value of the error frequency of the relay station in the relay station candidate list (FIG. 12) is incremented by 1 (S77). . Then, thereafter, it is determined whether or not the next candidate terminal can be selected as the relay station (S
78). In the determination of S78, it is determined that the next candidate terminal can be selected if the fixed station is not designated, the next candidate for the relay station exists, and the relay alternative device is set in advance. , S72, and selects a relay station other than the above-mentioned relay station that has failed to communicate. It should be noted that the operator sets in advance whether to retry transmission even if communication with the relay station fails once, to use another relay station, and how many other relay stations can be used. .

For example, when it is determined in S78 that the next candidate terminal cannot be selected, for example, the fixed station is designated, the next candidate for the relay station does not exist, or another relay station is selected but the transmission fails. Assuming that a communication error has occurred, it notifies the upper program of the communication error (S7).
9).

In the present embodiment, the above S74-
The communication result recording means described in the claims is achieved by the CPU 1 executing the program of S77.

Now, the relay station selection processing in S72 will be described. In this process, the relay station is selected by the following steps.

When a fixed station is registered in the fixed relay station information field of the relay station candidate list (FIG. 12), it is preferentially used as the relay station. If there is no fixed station registered in the fixed relay station information field, the first to nth
It will be selected from the POS terminals set in the relay station information field. Therefore, whether or not to use the fixed station is determined by whether or not the relay information is set in the fixed relay station information field. Since the fixed station is one of the relay station groups, the fixed station is selected from the relay station group. If the fixed station is not set, the fixed relay station information field is blank.

When there is no fixed station setting, the communication error occurrence rate of each relay station candidate (hereinafter referred to as the communication error rate)
Select a relay station from.

Here, the communication error rate of the terminal n is expressed by the following equation (1). Communication error rate = E _n × W _n / N _n (1) N _n : Number of communication of terminal n E _n : Number of communication error of terminal n W _n : Weight of terminal n In this formula (1), The weight W _{n functions as} a correction coefficient for the communication error rate (here, a multiplication factor of the communication error count E _n ).
The master machine sequentially calculates the communication error rate of each relay station candidate registered in the relay station candidate list, and selects the terminal with the lowest communication error rate as the relay station.

A terminal having a weight W _n set to a larger value than other terminals is very difficult to be selected as a relay station, but a terminal having a certain weight or more is used as a relay station. You may not.

The communication error rate is generally E _n / N _n
Is defined by Weight W with communication error rate E _n / N _n
The equation (1) is used when the correction is performed using _n .

When the communication error rates are the same, the relay station is selected from the number of times of communication.

Here, when the number of times of communication is compared, the product of the number of times of communication and the weight of each relay station candidate to be compared (N _n ×
W _n ) is calculated, and the terminal with the smallest number of communications is selected as the relay station.

When the number of times of communication is the same, the relay stations are selected in the order of registration in the terminal list of FIG.

As described above, the master machine of this embodiment has the learning function corresponding to the change of the communication environment, and has the function of always selecting the optimum relay station.

Regarding the above-mentioned selection of the relay station, the reason why the above is set as the highest priority condition is that it may be troublesome that the relay station fluctuates too much due to the above-mentioned learning function. This is so that it can be put out. Thus, the relay station is not automatically selected, and the intention of the user can be prioritized over the change in the communication environment in the store. As an example, considering a case where a specific POS terminal is planned to be disconnected from the system from a certain date and time, if the selection of the relay station is dynamic, it is planned to be disconnected from the system. It is difficult to disconnect the POS terminal during system operation, which may affect communication efficiency, but such a situation can be avoided if the relay station is fixedly designated.

The setting of the fixed station is performed by the operator operating the POS keyboard 20 (FIG. 5) of the master machine.
Further, the setting of the above-mentioned weight is also the same. When setting fixed stations and weights, the operator sets the POS keyboard 2 of the master machine.
By operating 0, the terminal station candidates necessary for communication between the master machine and each satellite machine can be displayed on the display unit 21 (FIG. 5).

In the above embodiment, the POS system in which the master machine performs centralized management while communicating with each satellite machine by polling has been described as an example. Therefore, only the master machine has a terminal list (FIG. 2) and satellites. Although the configuration has a registration list (FIG. 11), a relay station candidate list (FIG. 12), and a multi-stage relay station list (FIG. 13), it is not limited to this. As an example, when constructing a system in which the POS terminals for management are distributed, such as the information of a certain product is managed by a certain POS terminal and the information of another product is managed by another POS terminal. The POS terminals to be performed each have a terminal list, a satellite registration list, a relay station candidate list, and a multistage relay station list.

That is, similarly to the case where the master machine is mainly considered, the above-mentioned rule for deciding the relay station while considering other POS terminals can be applied to each POS terminal.
This enables communication using relay between all POS terminals. In this case, a specific terminal in the system becomes the key station (usually the master station is the key station in the POS system, but other terminals are also acceptable), creates a communication correlation table in the system, and then creates the communication correlation table. The table is propagated to each terminal in the system, and each terminal selects a relay station centered on itself based on the communication correlation table.

Further, even when the wireless handy terminal (HT) is used, when the HT communicates with the master machine while moving due to work such as inspection processing in the store, a terminal that can communicate with the master machine at a distance close to the HT is used. I can know.

As described above, the wireless LAN according to this embodiment
The communication system sends a response request packet from its own terminal to each of the other terminals before each terminal in the system enters the normal communication mode, and whether the response packet is returned from the terminal that sent the response request packet. Depending on whether or not direct communication is possible, it is checked for each individual terminal, and the results of the above investigations performed by each terminal in the system are combined into a single direct communication between all terminals belonging to the system. A terminal (master unit) that creates a communication correlation table that indicates whether communication is possible or not and that can be the starting station that is the source of data
Selects a relay station candidate terminal that can be a relay station necessary for communicating with a terminal that cannot directly communicate with its own terminal based on the above-mentioned communication correlation table, and selects a communication availability list, relay station candidate list, multistage When creating a relay station list and communicating with a terminal that cannot directly communicate with its own terminal, select one terminal from the relay station candidate list or multistage relay station list and send the packet to that terminal Then, each terminal in the system determines whether the received packet is a transfer request packet, and when the transfer request packet is received, transfers the packet to the transfer destination indicated in the packet. Is.

As described above, by utilizing the wireless communication function of the terminal itself in the system and using the terminal itself in the system as a relay station, the communication area is expanded without the need for a dedicated radio relay device. be able to. In addition, even if one terminal breaks down, it is possible to use another terminal in the system as a relay station, and it is not necessary to prepare an alternative device as in the case of using a dedicated radio relay device. . Further, since the same hardware (terminal) is used in the system, separate maintenance is unnecessary.

Incidentally, Japanese Patent Laid-Open No. 4-235652 discloses that
Disclosed is a communication system using a communication line as a medium, which transmits an opening request packet from a transmission node to a reception node via one or more transit nodes. The communication system described in this publication is intended to ensure security, and includes transit ID information (node address) in a station opening request packet including a destination address, a source address, and options (preceding node counter, preceding node address). )
Create a transit node information table based on this, check this against the access permission list already set in the receiving node, and reject the call as an invalid packet if any node address is not registered. When all the ID information of the transit node is verified, the virtual terminal is allowed to open. In this communication system, all nodes in the system interconnected by communication lines are able to communicate with each other because radio wave interference unlike wireless communication does not occur. There is no concept of discovering a terminal that can be a relay station. Therefore, the configuration is completely different from the configuration of this embodiment in which the transmitting station determines the relay station, determines the relay route, and sends the packet.

In the above embodiment, an example in which the wireless LAN communication system of the present invention is applied to a POS system is shown, but the wireless LAN communication system of the present invention can also be applied to a computer LAN or the like. The above embodiments are merely for clarifying the technical contents of the present invention, and should not be construed in a narrow sense by limiting only to such specific examples. The spirit of the present invention and the scope of the claims It can be implemented with various modifications.

[0153]

As described above, in the wireless LAN communication system according to the invention of claim 1, a response request signal is sent from the self terminal to each of the other terminals before each terminal in the system enters the normal communication mode. Is sent and whether or not direct communication is possible is checked for each individual terminal by whether or not the response signal is returned from the terminal that sent the response request signal. The survey results conducted by the terminals are combined into one, and a communication correlation table indicating whether or not direct communication between all terminals belonging to the system is possible is created in the system. A terminal that can be a station selects at least one relay station candidate terminal that can be a relay station necessary for communicating with a terminal that cannot directly communicate with its own terminal based on the above communication correlation table. Comprising a Tsugikyoku candidate terminal selection means, when communicating with the terminal can not self-terminal and the direct communication,
One of the relay station candidate terminals selected by the relay station candidate terminal selecting means is selected as a relay station, and a transfer request packet indicating a transfer destination is transmitted to the terminal, and
Each terminal in the system is provided with packet relay means for judging whether or not the received packet is a transfer request packet and transferring the packet to the transfer destination indicated in the packet when the transfer request packet is received. It has a structure.

Therefore, by utilizing the wireless communication function of the terminal itself in the system and using the terminal itself in the system as a relay station, the communication area can be expanded without the need for a dedicated radio wave relay device. You can Further, when relay is required, the terminal serving as the starting station has an effect of easily selecting a relay station candidate terminal based on the communication correlation table.

As described above, in the wireless LAN communication system according to the invention of claim 2, in the configuration of the invention of claim 1, the header part of the packet used for communication in the system actually transmits the packet. A destination field in which the terminal ID of the receiving terminal is set, and a source field in which the terminal ID of the terminal that actually sends the packet is set,
A starting station field in which the terminal ID of the starting station that is the source of the data included in the packet is set, and a final station field in which the terminal ID of the final station that finally receives the data included in the packet is set, The packet relay means comprises a relay information field in which a terminal ID of at least one relay station indicating a relay route on the way from the initial station to the final station can be set, and the packet relay means includes a destination field and a last station field of the received packet. If the terminal IDs do not match, it is determined that the packet is a transfer request packet, the terminal ID of the transfer destination is acquired based on the information in the relay information field of the packet, and the packet is transferred to the transfer destination. This is the configuration.

Therefore, in addition to the effect of the invention of claim 1, by using the packet having the above configuration, the communication area can be remarkably expanded while using a large number of relay stations, and the complication is complicated. It also has the effect of ensuring a relay route that avoids radio wave obstacles.

As described above, in the wireless LAN communication system according to the invention of claim 3, in the configuration of the invention of claim 1, the header part of the packet used for communication in the system actually transmits the packet. A destination field in which the terminal ID of the receiving terminal is set, and a source field in which the terminal ID of the terminal that actually sends the packet is set,
From the originating station field in which the terminal ID of the originating station that is the source of the data contained in the packet is set, and the final station field in which the terminal ID of the final station that finally receives the data contained in the packet is set The packet relay means is configured to determine that the packet is a transfer request packet when the terminal IDs of the destination field and the last station field of the received packet do not match,
The terminal ID of the last station field of the packet is acquired as the transfer destination terminal ID, and the packet is transferred to the transfer destination.

Therefore, in addition to the effect of the invention of claim 1, when the system is operated by limiting the relay to only one stage, the relay using the packet having the economical structure without the relay information field is required. This also brings about the effect that efficient communication can be performed.

As described above, in the wireless LAN communication system according to the invention of claim 4, in the configuration of the invention of claim 1, the terminal that can be the originating station that is the source of data is:
Every time a transfer request packet is transmitted to the relay station candidate terminal selected by the relay station candidate terminal selecting means, the presence or absence of a communication error is determined depending on whether or not a reception completion signal is returned from the relay station candidate terminal. A communication result recording means for recording the number of times of communication with the relay station candidate terminal and the number of occurrences of communication errors for each relay station candidate terminal, and when performing communication with a terminal that cannot directly communicate with the own terminal. If there are multiple relay station candidate terminals, calculate the communication error occurrence rate from the number of communication times and communication error times of those relay station candidate terminals, and select the relay station candidate terminal with the lowest communication error occurrence rate as the relay station. And a relay station selecting means for performing the operation.

Therefore, in addition to the effect of the invention of claim 1, the learning function corresponding to the change of the communication environment can bring about the effect that the optimum relay station having a low communication error occurrence rate can be selected.

As described above, in the wireless LAN communication system according to the invention of claim 5, in the configuration of the invention of claim 4, the terminal that can be the originating station that is the source of the data is:
For each relay station candidate terminal, a weighting factor setting means capable of presetting a weighting factor representing the difficulty of being selected as a relay station is provided, and the relay station selecting means is one of a plurality of relay station candidate terminals. When selecting relay station candidate terminals as relay stations, the communication error occurrence rates of those relay station candidate terminals are corrected by weighting factors, and the corrected communication error occurrence rates of the relay station candidate terminals are compared and relayed. This is a configuration for selecting a station.

Therefore, in addition to the effects of the inventions of claim 1 and claim 4, a terminal that is frequently used for processing other than communication is less likely to become a relay station than other relay station candidates due to weighting. However, there is also an effect that the original processing capacity of the terminal can be prevented from being deteriorated by the relay communication processing.

In the wireless LAN communication system according to the sixth aspect of the present invention, as described above, in the configuration of the fourth or fifth aspect of the invention, the terminal that can be the originating station that is the source of the data is directly connected to its own terminal. Specific relay station candidate terminal among the plurality of relay station candidate terminals when there are a plurality of relay paths via a plurality of relay station candidate terminals that can be selected as a communication path with a terminal that cannot communicate Is previously set as a fixed relay station, the fixed relay station selecting means is configured to enable the fixed relay station to select one relay station candidate terminal as a relay station from a plurality of relay station candidate terminals. If set, only the terminal set as the fixed relay station is selected as the relay station.

Therefore, when it is troublesome for the relay station to change due to the learning function of the invention of claim 4 or 5, the user's intention is prioritized over the change of the communication environment, and the relay station candidates are selected. It is possible to select a fixed relay station. Therefore, in addition to the effect of the invention of claim 1 and the effect of the invention of claim 4 or 5, the relay station is fixed when necessary, such as when a specific terminal is disconnected from the system for maintenance or the like. The effect that it can be specified so as not to hinder the operation of the system is also obtained.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention and is an explanatory diagram showing a communication correlation table created in a POS system to which a wireless LAN communication system of the present invention is applied.

FIG. 2 is an explanatory diagram showing a terminal list in which POS terminals belonging to the POS system are registered.

FIG. 3 is an explanatory diagram showing a communication availability list created by each POS terminal of the POS system.

FIG. 4 is an explanatory diagram showing a terminal link table added to a packet when the POS system is in a communication permission list creation mode and representing a data transmission route.

FIG. 5 is a perspective view showing an appearance of the POS terminal.

FIG. 6 is a block diagram showing an internal configuration of the POS terminal.

FIG. 7 is a flowchart showing the operation of the master machine when the POS system is in the communication correlation table creation mode.

FIG. 8 is a flowchart showing a communication availability list creation routine executed by the POS terminal when the POS system is in the communication correlation table creation mode.

FIG. 9 is a flowchart showing the operation of the satellite machine when the POS system is in the communication correlation table creation mode.

FIG. 10 is an explanatory diagram showing a packet configuration used when the POS system is in a communication correlation table creation mode.

FIG. 11 is an explanatory diagram showing a satellite registration list indicating whether or not the satellite machine can directly communicate with the master machine.

FIG. 12 is an explanatory diagram showing a relay station candidate list listing relay station candidates for one-stage relay.

FIG. 13 is an explanatory diagram showing a multi-stage relay station list in which multi-stage relay relay stations are listed in series.

FIG. 14 is an explanatory diagram showing a simple relay pattern.

FIG. 15 is an explanatory diagram showing a multi-path type relay pattern.

FIG. 16 is an explanatory diagram showing a multi-branching relay pattern.

FIG. 17 is an explanatory diagram showing a multistage relay pattern.

FIG. 18 is an explanatory diagram for explaining the simple relay pattern of FIG. 14 according to the communication distance of each POS terminal.

FIG. 19 shows the multi-path type relay pattern of FIG.
It is explanatory drawing demonstrated with the communication distance of a terminal.

FIG. 20 is an explanatory diagram illustrating the multi-stage relay pattern of FIG. 17 according to the communication distance of each POS terminal.

FIG. 21 is an explanatory diagram showing an example of a POS system having a multi-path type relay pattern according to the communication distance of each POS terminal.

22 is an explanatory diagram showing a communication correlation table created in the POS system shown in FIG. 21.

23 is an explanatory diagram showing a logical product table based on the master machine A that is derived from the communication correlation table shown in FIG. 22.

FIG. 24 is an explanatory diagram showing an example of a POS system having a multi-branching type relay pattern according to the communication distance of each POS terminal.

25 is an explanatory diagram showing a communication correlation table created in the POS system shown in FIG. 24.

26 is an explanatory diagram showing a logical product table based on the master machine A, which is derived from the communication correlation table shown in FIG. 25.

27 is an explanatory diagram showing a logical product table based on the satellite machine B that can directly communicate with the master machine A, targeting the logical product table based on the master machine A in FIG.

28 is an explanatory diagram showing a logical product table based on the satellite machine C capable of directly communicating with the master machine A, targeting the logical product table based on the master machine A of FIG.

29 is an explanatory diagram showing a logical product table based on the satellite machine F capable of directly communicating with the master machine A, targeting the logical product table based on the master machine A of FIG.

FIG. 30 is an explanatory diagram showing an example of a POS system having a multi-stage type relay pattern according to the communication distance of each POS terminal.

31 is an explanatory diagram showing a communication correlation table created in the POS system shown in FIG. 30.

32 is an explanatory diagram showing a logical product table based on the master machine A derived from the communication correlation table shown in FIG. 31. FIG.

33 is an explanatory diagram showing a logical product table based on the satellite machine C derived from the communication correlation table shown in FIG. 31.

FIG. 34 is an explanatory diagram showing a configuration of a packet used when the POS system is in the communication mode.

FIG. 35 is an explanatory diagram showing another configuration of a packet used when the POS system is in the communication mode.

36 is a flowchart showing processing when a satellite device receives a packet in communication using the packet shown in FIG. 34 or FIG.

FIG. 37 is an explanatory diagram showing a structure of a packet for one-station relay used when the number of relay stages in the POS system is limited to one.

38 is a flowchart showing a process when a satellite machine receives a packet in communication using the packet for one-station relay of FIG. 37. FIG.

FIG. 39 is a flowchart showing a packet transmission process of the master machine having the function of optimizing the relay station.

FIG. 40 is a block diagram showing a schematic configuration of a conventional wired LAN system.

FIG. 41 is a block diagram showing an example of a conventional wireless communication system.

FIG. 42 is a block diagram showing another example of the conventional wireless communication system.

FIG. 43 is an explanatory diagram showing a general packet configuration used in conventional wireless communication.

[Fig. 44] Fig. 44 is an explanatory diagram for explaining a radio wave reach distance and a situation of occurrence of a communication disabled state due to an obstacle in a conventional wireless communication system.

[Explanation of symbols]

 1 CPU 2 ROM 3 RAM 6 Screen Controller 7 POS Keyboard Controller 13 Communication Control Controller 14 Antenna Section 20 POS Keyboard 21 Display Section

Claims (6)

[Claims] 1. A wireless local area network communication system comprising a plurality of terminals equipped with wireless communication means, wherein each terminal in the system is set in a normal communication mode,
Send a response request signal from your own terminal to each other terminal,
Each terminal in the system is equipped with a direct communication permission / inspection means for checking whether or not direct communication is possible for each individual terminal, depending on whether or not the response signal is returned from the terminal that sent the response request signal. Combining the above survey results into one, a communication correlation table showing whether or not direct communication between all terminals belonging to the system is possible is created in the system, and the terminal that can be the originating station that is the source of the data is A relay station candidate terminal selecting means for selecting at least one relay station candidate terminal that can be a relay station necessary for communicating with a terminal that cannot directly communicate with the self terminal based on the communication correlation table, When communicating with a terminal that cannot directly communicate with its own terminal, one of the relay station candidate terminals selected by the relay station candidate terminal selecting means is selected as a relay station, and At the end, a transfer request packet indicating the transfer destination is transmitted, and each terminal in the system determines whether the received packet is a transfer request packet and indicates in the packet when the transfer request packet is received. A wireless local area network communication system comprising packet relay means for transferring a packet to a specified transfer destination. 2. A header part of a packet used for communication in the system is a terminal I of a terminal which actually receives the packet.
A destination field in which D is set, a source field in which the terminal ID of the terminal that actually sends the packet is set, and a terminal ID of the starting station that is the source of the data included in the packet are set. A starting station field, a final station field in which a terminal ID of the final station that finally receives the data contained in the packet is set, and a terminal of at least one relay station indicating a relay route on the way from the initial station to the final station The packet relay means is composed of a relay information field in which an ID can be set, and the packet relay means determines that the packet is a transfer request packet when the terminal IDs of the destination field and the last station field of the received packet do not match. The terminal ID of the transfer destination is acquired based on the information in the relay information field of the packet, and the packet is transferred to the transfer destination. The wireless local area network communication system according to claim 1, wherein: 3. A header part of a packet used for communication within the system is a terminal I of a terminal which actually receives the packet.
A destination field in which D is set, a source field in which the terminal ID of the terminal that actually sends the packet is set, and a terminal ID of the starting station that is the source of the data included in the packet are set. The initial station field and the final station field in which the terminal ID of the final station that finally receives the data contained in the packet are set are included. The packet relay means is a destination field and a final station field of the received packet. If the terminal ID of the packet does not match that of the packet, it is determined that the packet is a transfer request packet, the terminal ID of the last station field of the packet is acquired as the terminal ID of the transfer destination, and the packet is transferred to the transfer destination. The wireless local area network communication system according to claim 1, wherein the wireless local area network communication system transfers. 4. A terminal which can be a starting station which is a source of data is received from a relay station candidate terminal every time a transfer request packet is transmitted to the relay station candidate terminal selected by the relay station candidate terminal selecting means. Communication result recording means for judging the presence or absence of a communication error depending on whether or not a completion signal is returned, and recording the number of times of communication with each relay station candidate terminal and the number of occurrence of communication error for each relay station candidate terminal. , When there are multiple relay station candidate terminals when communicating with a terminal that cannot directly communicate with its own terminal, calculate the communication error occurrence rate from the number of communication times and the number of communication error of those relay station candidate terminals. 2. The wireless local area network according to claim 1, further comprising: a relay station selecting unit that selects a relay station candidate terminal having the lowest communication error occurrence rate as a relay station. Communication system. 5. A terminal which can be a starting station which is a source of data is provided with a weighting factor setting means capable of presetting a weighting factor representing difficulty of being selected as a relay station for each relay station candidate terminal, When selecting one relay station candidate terminal as a relay station from a plurality of relay station candidate terminals, the relay station selecting means corrects the communication error occurrence rate of these relay station candidate terminals by a weighting factor, The wireless local area network communication system according to claim 4, wherein the relay stations are selected by comparing the occurrence rates of communication errors of the subsequent relay station candidate terminals. 6. A terminal which can be a starting station which is a source of data is a plurality of relay paths via a plurality of relay station candidate terminals which can be selected as a communication path with a terminal which cannot directly communicate with the own terminal. A fixed relay station setting means capable of setting a specific relay station candidate terminal among the plurality of relay station candidate terminals as a fixed relay station in advance, the relay station selecting means is a plurality of relay station candidates. When a fixed relay station is set when one relay station candidate terminal is selected as a relay station from the terminals, only the terminal set as the fixed relay station is selected as the relay station. The wireless local area network communication system according to claim 4 or 5.