JP3588101B2 - Access control method and device - Google Patents

Description

  According to the present invention, in a transmission mode in which a master station and a plurality of slave stations are star-type, bus-type or one-to-one connection, but logically share a line, one logical line is divided and used by a plurality of slave stations. Access control method and device thereof.

FIG. 26 shows a conventional access control method and a conventional access control method in which one logical line is divided and used by a plurality of slave stations in a transmission mode in which a master station and a plurality of slave stations share a line in a star configuration. FIG. 2 is a configuration diagram showing a subscriber line to be applied, in which 100 is a slave station and 101 is a master station.
In the conventional access control method and its device, for example, as disclosed in Patent Document 1, when communication is performed using a multiple access channel, a master station is fixedly assigned to each slave station. The pre-assignment method in which each slave station performs data transmission using a slot, or the master station dynamically allocates a slot in response to a reservation request of the slave station, and the slave station transmits data using the reserved slot. Demand assignment method. In particular, in the technique disclosed in Patent Document 1, one of the pre-assignment method and the demand assignment method is determined for each time slot to increase transmission efficiency.

JP-A-2-10926

  Since the conventional access control method and its apparatus are configured as described above, in the case of a subscriber line in which voice is the main stream, a pre-assignment method that always secures the line capacity up to the local exchange, and further increases the transmission efficiency It was sufficient to perform demand access on a call-by-call basis for the necessary parts.However, transmission capacity such as computer communication changed every moment, and in some cases there was almost no access to the network. When large amounts of data need to be sent and received via the network, the transmission efficiency cannot be expected to improve with the pre-assignment method, and the transmission path length is long even with the demand access method, and the amount of data to be transmitted changes every moment. Then, since the time required for the demand processing becomes long, there is a problem that the improvement of the transmission efficiency cannot be expected similarly to the pre-assignment method.

  Further, when there is no data to be transferred even if the line capacity is secured once on demand, there is a problem that the time during which valid information does not flow on the line increases and the line is not effectively used.

  SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and provides an access control method and apparatus capable of improving the transmission efficiency in a multiple access channel for highly bursty traffic such as computer communications. The purpose is to:

  An access control method according to the present invention detects an inflow amount of information flowing into a slave station, sequentially stores information on the detected inflow amount together with identification information of the slave station, and stores the stored information on the inflow amount. Based on the above, generate slot allocation information of the slot to be allocated to each slave station according to the order, based on the generated slot allocation information for each slave station, each slave station is assigned to itself. This information is used to transmit the information to be transmitted using the own slot.

  In the access control method according to the present invention, transmission timing is delayed until a slot carrying information to be transmitted arrives based on slot allocation information for each slave station.

  An access control device according to the present invention includes: an inflow amount detection unit that detects an inflow amount of information flowing into a slave station; and information on the inflow amount detected by the inflow amount detection unit from each slave station to the master station. A slave station-side inflow amount transmitting unit that multiplexes and sends the multiplexed information in accordance with the slot allocation information, and information about the inflow amount sent to the master station by the slave station-side inflow amount transmission unit, together with the identification information of the slave station; Inflow amount storage means, and slot allocation information generation means for generating the slot allocation information of slots to be allocated to each slave station according to the order based on the information on the inflow amount stored by the inflow amount storage means. Master station transmitting means for multiplexing the slot assignment information generated by the slot assignment information generating means from the master station to each of the slave stations, and transmitting the multiplexed information; and A slave station side transmitting means for each slave station to know its own assigned slot based on the slot allocation information sent to each slave station and to transmit information to be transmitted by the own slot; And so on.

  The access control device according to the present invention, based on the slot allocation information for each slave station generated by the slot allocation information generating means, each of the slave stations delays the transmission timing until a slot carrying information to be transmitted arrives. This is provided with delay means for causing the delay.

  According to the present invention, an inflow amount detecting step of detecting an inflow amount of information flowing into a slave station, and an inflow step of sequentially storing information on the inflow amount detected in the inflow amount detection step together with identification information of the slave station. An amount storing step; a slot allocation information generating step of generating slot allocation information of slots to be allocated to the slave stations according to the order based on the information on the inflow amount stored in the inflow amount storing step; Based on the slot allocation information for each of the slave stations generated in the slot allocation information generating step, each of the slave stations knows its own assigned slot and transmits information to be transmitted by the assigned slot. Since the transmission process is performed, the use efficiency at the time of congestion of the transmission path is improved.

  According to the present invention, there is provided a delay step of delaying transmission timing until a slot carrying information to be transmitted arrives based on the slot allocation information for each of the slave stations generated in the slot allocation information generating step. Accordingly, each of the slave stations can wait for the delay process to transmit information to be sent to the master station to the master station, which has the effect of improving the use efficiency when congesting the transmission path.

  According to the present invention, the inflow amount detecting means for detecting the inflow amount of the information flowing into the slave station, and the information on the inflow amount detected by the inflow amount detection means is allocated from each of the slave stations to the master station. A slave-station-side inflow-amount transmitting unit that multiplexes and sends the information on the inflow amount sent to the master station by the slave-station-side inflow-amount transmission unit, together with identification information of the slave station; Storage means; slot allocation information generating means for generating the slot allocation information of the slots to be allocated to each of the slave stations according to the order based on the information on the inflow amount stored by the inflow amount storage means; Master-station-side transmitting means for multiplexing the slot allocation information generated by the allocation-information generating means from the master station to each of the slave stations; and transmitting the multiplexed slot allocation information to each of the slave stations by the master-station-side transmitting means. Each of the slave stations knows its own slot allocated to itself based on the assigned slot allocation information, and has slave station transmitting means for transmitting information to be transmitted by the own slot. Therefore, there is an effect that the use efficiency when the transmission path is congested is improved.

  According to the present invention, based on the slot assignment information for each slave station generated by the slot assignment information generating means, each slave station delays transmission timing until a slot carrying information to be transmitted arrives. Thus, each slave station can transmit information to be sent to the master station after waiting by the delay process to the master station, and the use efficiency at the time of congestion of the transmission path is improved.

Hereinafter, an embodiment of the present invention will be described.
Reference Example 1.
FIGS. 1A and 1B are block diagrams showing a main configuration of a master station and a slave station of an access control apparatus to which the access control method of Reference Example 1 is applied, wherein FIG. 1A is the master station, and FIG. It is a block diagram which shows the structure of a slave station. The reference example is not an embodiment of the present invention. In the figure, reference numeral 1 denotes an idle line determination unit in a master station that monitors information from a slave station and determines whether or not the slave station is an idle line. The pre-assigned TDMA slot information generation unit 3 which determines a time slot for TDMA (Time Division Multiple Access) in advance converts the slot information to allocate the idle line determined by the idle line determination unit 2 to another slave station. The TDMA slot information conversion unit 4 is a multiplexing unit that multiplexes the converted TDMA slot information into downlink data.

  Reference numeral 5 denotes a TDMA slot information receiving unit of the slave station which receives the TDMA slot information broadcast by the master station, 6 denotes a delay unit (delay means) for holding the received TDMA slot information up to a predetermined transmission phase, and 7 denotes a delay. A FIFO unit for storing upstream data in order to transmit data to the master station at the timing output from the unit 6.

Next, the operation will be described.
In the TDMA slot information converting section 3 in the master station, the frame period T is predetermined, and the preassigned TDMA slot information predetermined by the preassigned TDMA slot information generating section 2 is selected at the beginning of the frame, and is sent to the multiplexing section 4. The pre-assigned TDMA slot information is output and distributed to all slave stations. In the slave station, the pre-assigned TDMA slot information receiving unit 5 receives the distributed and transferred pre-assigned TDMA slot information, and the uplink data waiting in the FIFO unit 7 is transmitted to the master station according to the received pre-assigned TDMA slot information. You.
The method of distributing the pre-assigned TDMA slot information includes a method of specifying each slot described in “Time slot allocation method in ATM-PDS, 1993 IEICE Autumn Meeting B-668”, and a method of collectively specifying a plurality of slots. By any of the methods.

  Uplink information is separated into blocks of information called cells, and information from the slave station to the master station is transferred in cell units. A code that does not include valid information is defined in the cell, and the idle line determination unit 1 recognizes the idle cell by receiving the defined code at the master station. Further, the idle line determination unit 1 determines whether or not the lines from all the pre-assigned slave stations are idle lines by, for example, the following two methods. The first method is a case where n consecutive idle cells are detected, and the second method is a case where one or more idle cells out of k cells are received m times or more.

  For the detected idle line, a conversion table indicating the transfer relationship is created in the TDMA slot information conversion unit 3 using, for example, a separately determined algorithm, the preassign slot number is changed by this conversion table, and the idle line is changed to the transfer line. Be changed.

  FIG. 2 is a flowchart illustrating an example of the algorithm. As shown in this flowchart, the determination condition of step ST101 is satisfied at the beginning of the frame, and the contents of the conversion table are cleared by the subsequent step ST102. In this case, the TDMA slot information is the pre-assigned TDMA slot information generated by the pre-assigned TDMA slot information generator 2 shown in FIG.

When the idle line information Cid is detected by the idle line determination unit 1, the determination result becomes “Yes” with respect to the determination condition in step ST103, and in the subsequent step ST104, the conversion source idle described in the conversion table is described based on the idle line information Cid. Search the line information Cid. If it is not registered in the conversion table, it is determined that the line is a new idle line.
On the other hand, when the idle line information Cid has already been registered as the conversion source idle line information Cid in the conversion table, the determination result for the determination condition of step ST104 is “No”, and no processing is performed.
If the result of the determination in step ST103 is affirmative, and if it is determined in step ST104 that the line is a new idle line, then in step ST105, the pre-assignment ID immediately before or after the pre-assigned ID configured in the chain. The assignment ID is detected as the transfer destination Nid of the idle line.

  An example of this chain configuration is shown in FIG. In the example of FIG. 7A, it is assumed that six preassigned IDs of the slave stations 1, 3, 5, 6, 7, and 8 are currently valid. In FIG. 3A, the chains are configured in the ascending order by the pre-assigned ID, and the chain is configured such that the number following the last 8 is 1. In this case, a case is considered in which, when an idle line is detected, the next preassign ID is defined as the transfer destination Nid of the idle line. For example, when the preassign ID 3 is detected as new idle line information Cid, the preassign ID of 5 is the transfer destination Nid of the idle line.

  Returning to FIG. 2, when it is determined in step ST106 that the detected idle line information Cid matches the transfer destination Nid in step ST105, all the pre-assigned lines go through the chain configuration and become idle lines. If it is recognized, the process proceeds to the previous step ST107, in which all the conversion tables are reset, and the pre-assignment is set.

  On the other hand, when the determined result that the detected idle line information Cid does not match the transfer destination Nid in step ST105 is obtained in step ST106, in step ST108, the transfer destination Nid is set as a conversion source of the conversion table. It is determined whether or not it has already been registered. The case where the transfer destination Nid is already registered as the conversion source of the conversion table is a case in which the circuit has gone through the chain configuration and the line has been transferred to the conversion destination of the conversion table. It is assumed that the preassigned ID of the conversion destination of the idle line is the transfer destination Nid which has already been registered as the conversion source of the conversion table.

  FIG. 3B shows that all pre-assigned lines are recognized as idle lines and go around the chain configuration, and it is determined in step ST106 that the detected idle line information Cid matches the transfer destination Nid. This shows the state of the conversion table to be reset. That is, when all the pre-assigned lines are idle lines, the line with the pre-assign ID 3 is first detected as new idle line information Cid, the line with the pre-assign ID 5 becomes the transfer destination Nid of the idle line, and The line with the assignment ID 5 is detected as new idle line information Cid, and the line with the pre-assignment ID 6 becomes the transfer destination Nid of the idle line. As a result, the line with the preassign ID 1 is finally detected as new idle line information Cid, and the line with the preassign ID 3 becomes the transfer destination Nid of the idle line. The line of the pre-assignment ID 3 that has become the transfer destination Nid is already registered as the conversion source at the beginning of the conversion table. Accordingly, the determination result for the determination condition in step ST108 is "Yes", and in step ST109, the conversion source: preassign ID3 for the conversion source: preassign ID3 in the conversion table is set to preassign ID3. As a result, the determination result for the determination condition in step ST106 is “Yes”, and the conversion table is reset in step ST107.

  When the determination result of step ST108 is "No", the process proceeds to step ST110, and the conversion source is written into the conversion table as Cid, and the conversion destination is written as the transfer destination Nid found at step ST105.

  As a result, the conversion table for transferring the detected idle line to the transfer destination Nid of the non-idle line is updated.

  As described above, in the first embodiment, the TDMA slot of the idle line is changed to the pre-assigned slot number of the transfer destination line, assigned to the slave station via the multiplexing unit 4, and transferred. There is an effect that an access control method and an access control device that can increase the transmission efficiency due to an increase in the bandwidth of the transferred line and also improve the overall transmission efficiency between the slave station and the master station are obtained.

Reference example 2.
FIGS. 4A and 4B are block diagrams showing main configurations of a master station and a slave station of an access control device to which the access control method of Reference Example 2 is applied, wherein FIG. 4A is the master station, and FIG. It is a block diagram which shows the structure of a slave station. 4, the same or corresponding parts as in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.
In the reference example 1, the TDMA slot conversion unit 3 is provided in the master station. In the reference example 2, the TDMA slot information conversion unit is provided in the slave station. In FIG. 4, reference numeral 3a denotes the TDMA slot information converter, and 8 denotes an idle line information receiver for receiving idle line information Cid sent from the master station.

Next, the operation will be described.
The idle line number Cid detected by the idle line determination unit 1 of the master station is multiplexed by the multiplexing unit 4 and transferred to all slave stations. On the slave station side, the pre-assigned TDMA slot receiving unit 5 receives the pre-assigned TDMA slot, the idle line information receiving unit 8 receives the idle line information Cid sent from the master station, and the TDMA slot information converting unit 3a. The transfer line Nid for the idle line of the idle line information Cid is determined by the same algorithm as in the first embodiment, and the line is transferred.

  As described above, in the second embodiment, since the TDMA slot information exchange unit 3a is provided in the slave station, the function of converting the TDMA slot information, which is a load on the master station in the first embodiment, is reduced. There is an effect that an access control method and an access control device that can reduce the processing time of the master station, which is a problem when many slave stations are connected to one master station, can be obtained.

Reference example 3.
In the second embodiment, the function of the TDMA slot information conversion unit is realized on the slave station side. In the third embodiment, an idle line determination unit is further provided on the slave station side. FIG. 5 is a block diagram showing a main configuration of a master station and a slave station of an access control apparatus to which the access control method according to the third embodiment of the present invention is applied. FIG. 2B is a block diagram showing the configuration of the slave station. In FIG. 5, the same or corresponding parts as those in FIG. 4 are denoted by the same reference numerals, and description thereof will be omitted.
In FIG. 5, reference numeral 9 denotes an idle cell detector for detecting an idle cell on the master station side; 1a, an idle line determination section provided on the slave station side; and 10, an idle cell information receiving section provided on the slave station side. is there.

Next, the operation will be described.
In the reference example 3, the idle cell detection unit 9 detects an idle cell in the master station, and further multiplexes information on whether or not an idle cell is detected in the multiplexing unit 4 and transfers the information to the slave station. On the slave station side, the transferred information is received by the idle cell information receiving unit 10, and the idle line determining unit 1a determines which line is the idle line. The determination of the idle line is performed by one of the two methods described in the first embodiment. Then, similarly to the second embodiment, the TDMA slot information conversion unit 3a determines the transfer line Nid for the idle line Cid by the same algorithm as that described in FIG. 2 of the first embodiment, and realizes the transfer of the line.

  As described above, in the third embodiment, since the TDMA slot information exchange unit 3 is provided in the slave station, the TDMA slot information conversion function, which is a load on the master station in the first embodiment, is replaced by the second embodiment. In addition, the slave station is provided with an idle line determination unit 1a, and the slave station determines an idle line, thereby dispersing processing. Therefore, many slave stations are connected to one master station. In this case, there is an effect that an access control method and an access control device that can further reduce the processing time of the master station, which is a problem in the case of the above, can be obtained.

Reference example 4.
In the above-described Reference Examples 1 to 3, the configuration of the TDMA slot information conversion unit 3 that determines the transfer line is configured, for example, by a pre-assigned ID of the line number, and the previous one based on the chain configuration. Alternatively, the idle line detected is transferred to the line with the next pre-assigned ID. However, in this reference example 4, the highest load having the highest load in the pre-assignment assignment state or the line assignment state after the assignment is assigned. The load line is determined by monitoring information from the slave station at the master station, and the transfer line Nid is determined for the highest load line. In this method, the line can be transferred to a line with a higher load, so that higher transmission efficiency can be improved.

  FIG. 6 is a block diagram illustrating a main configuration of a master station of an access control device to which the access control method of Reference Example 4 is applied. 6, the same or corresponding parts as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. In FIG. 6, reference numeral 11 denotes a highest load line detecting unit for detecting a highest load line based on information from a slave station, and 19 denotes a TDMA slot information conversion for determining a transfer line Nid for the highest load line detected by the highest load line detecting unit 11. Department.

FIGS. 7, 8, and 9 are block diagrams showing configurations for realizing the function of detecting the highest load line by the highest load line detection unit 11, as shown in FIGS. 7, 8, and 9, respectively. With such a configuration, the highest load line can be detected.
In FIG. 7, reference numerals 12 and 13 denote idle cell counting units for monitoring and counting idle cells to be transferred when there is no valid information regarding information from the child station for each child station. This is a minimum value detection unit that detects the minimum value among the counted numbers of idle cells counted in each case, that is, the child station of the least idle cell among the currently used child stations.
In FIG. 8, reference numerals 15 and 16 denote valid cell count units for monitoring and counting valid cells other than idle cells for each slave station, and 17 denotes a count of valid cells counted by the valid cell count units 15 and 16 respectively. Is the maximum value, that is, the maximum value detection unit that detects the slave station having the largest number of valid cells among the slave stations currently used.
In FIG. 9, reference numeral 18 denotes the maximum cell coverage expressed as the number of valid cells with respect to all cells (total of valid cells and idle cells) from the count numbers of both idle cells and valid cells used in FIGS. Is the maximum cell capacity detection unit that is obtained by calculating.

  Next, the operation of the master station and the TDMA slot information converter 19 of the master station of the fourth embodiment will be described. When the highest load line detecting section 11 detects the highest load line by the method shown in FIG. 7, the TDMA slot information converting section 19 outputs the TDMA slot information converting section 19 among the currently used slave stations based on the detection result of the highest load line detecting section 11. The line of the slave station with the least number of idle cells is the highest load line. When the highest load line detecting unit 11 detects the highest load line by the method shown in FIG. 8, the TDMA slot information conversion unit 19 outputs the currently used slave station based on the detection result of the highest load line detecting unit 11. The line of the slave station of the largest effective cell is set as the highest load line. When the highest load line detection unit 11 detects the highest load line by the method shown in FIG. 9, the TDMA slot information conversion unit 19 outputs the currently used slave station based on the detection result of the highest load line detection unit 11. Of these, the line of the slave station having the highest cell capacity is set as the highest load line.

  In the master station, the highest load line detection unit 11 detects the highest load line based on the information from the slave station by one of the methods shown in FIGS. The TDMA slot information is changed so that the idle line detected by the line determination unit 1 is transferred to the slave station of the detected highest load line. The configuration of the slave station is the same as that of FIG. 1 shown in the first embodiment, and the operation is also the same.

  In FIG. 7, FIG. 8, and FIG. 9, when the next highest load line is determined after the highest load line is once determined, a method of including the once determined highest load line as a candidate for the next highest load line, Alternatively, a method of not recognizing the second highest load line for the once determined highest load line until all the remaining lines not determined as idle lines are determined as the highest load line is also an option. It is considered as.

  As described above, in Reference Example 4, since the idle line is transferred to the slave station of the highest load line detected by the highest load line 11, the idle line is transferred to the slave station transmitting the largest amount of information. There is an effect that an access control method and an access control device that can appropriately improve the transmission efficiency of the slave station having the largest amount of information and the overall transmission efficiency by expanding the bandwidth of the line of the slave station are provided.

Reference example 5.
In the reference example 4, the detection of the highest load line is determined by monitoring information from the slave station in the master station. In the reference example 5, the remaining amount of information in the slave station from the slave station is determined by the master station. The parent station determines the transfer line based on the notification of the remaining amount.

  FIG. 10 is a block diagram illustrating a main configuration of a master station and a slave station of an access control device to which the access control method according to the fifth embodiment is applied. 10, the same or corresponding parts as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. In FIG. 10, reference numeral 20 denotes a remaining amount extracting / comparing unit provided in the master station for comparing the remaining amount transmitted from each slave station at the beginning of a frame. Reference numeral 21 denotes a frame end remaining amount monitor unit provided on the slave station side for monitoring the amount of information remaining in the upstream FIFO unit 7 at the end of the frame. A multiplexing unit that multiplexes data on the amount of the remaining information to notify the master station of the amount of the remaining information.

Next, the operation will be described.
In the slave station, the remaining amount of information stored in the upstream FIFO unit 7 at the end of the frame or the like is monitored by the frame end time remaining amount monitoring unit 21 and slots for notifying the slave stations in order are allocated in advance. The multiplexing unit 22 multiplexes data on the remaining amount to notify the master station of the remaining amount.

The master station compares the remaining amount transmitted from each slave station at the beginning of the frame and ranks the load lines. There are many possible ways of assigning priorities. For example, priorities are assigned by the following method, and the idle channels are assigned in the TDMA slot information conversion unit 19 in the descending order of the priorities.
There are, for example, the following four methods of allocation according to the transmitted remaining amount.
(1) The order with the largest remaining amount * coefficient (2) The order with the largest (remaining amount * coefficient-1 frame allocation) (3) The order with the largest (remaining amount * coefficient / 1 frame allocation amount) (4) ( The remaining amount * coefficient-1 frame allocation amount) * coefficient / frame allocation amount).
The method (1) evaluates the remaining amount in descending order, and the method (2) multiplies the remaining amount by an appropriate coefficient to subtract the allocated amount of one frame. The remaining amount after one frame is predicted by subtracting the allocation amount of one frame after prediction. The method of (3) multiplies the method of (1) by a coefficient and divides it by the allocated amount of one frame. Therefore, the remaining amount is the normalized amount by the allocated amount. The method of (4) is the method of (2). The value is obtained by normalizing the method with the assigned amount.

  In the fifth embodiment, similarly to the fourth embodiment, after the highest load line is determined once and the next highest load line is determined, the once determined highest load line is set as a candidate for the next highest load line. And a new evaluation value is determined by subtracting the capacity value of the transferred line or the value obtained by multiplying the value by a specific coefficient from the value in the above method (1), (2) or (3), There is a method of changing the priority.

  As described above, in the fifth embodiment, the remaining amount of the master station is determined based on the amount of information remaining in the upstream FIFO unit 7 at the end of the frame monitored by the remaining amount monitoring unit 21 at the end of the frame. The comparison unit 20 compares the remaining amount transmitted from each slave station at the beginning of the next frame, assigns a priority to the load lines based on the comparison result, and assigns the transfer destination of the idle line in descending order of the priority. Is determined, the idle lines are transferred in the order of the slave stations having a large amount of information to be transmitted, the bandwidth of the line of the slave station is widened, and the transmission efficiency of the slave station having a large amount of information and the overall transmission efficiency are accurately determined. Thus, there is an effect that an access control method and an access control device which can be improved can be obtained.

Reference example 6.
In the reference example 5, the slave station monitors the remaining amount of the FIFO unit 7 at the end of the frame and transfers the remaining amount to the master station, and determines the line with the highest load based on this information. Then, the inflow amount per frame of the FIFO unit 7 of the slave station is monitored, and the remaining amount of the FIFO unit 7 at the end of the next frame is predicted based on the inflow amount and the remaining amount. To estimate a high load line.

  FIG. 11 is a block diagram illustrating a main configuration of a master station and a slave station of an access control apparatus to which the access control method according to the sixth embodiment is applied. In FIG. 11, the same or corresponding parts as in FIGS. 1 and 10 are denoted by the same reference numerals, and description thereof is omitted. In FIG. 11, reference numeral 23 denotes an inflow amount monitoring unit (inflow amount detecting means) for measuring an inflow amount x into the FIFO unit 7 of one frame, and reference numeral 24 denotes a FIFO unit monitored at the end of the frame by the frame end remaining amount monitoring unit 21. 7 based on the remaining amount b of No. 7 and the inflow amount x monitored by the inflow amount monitoring unit 23, a prediction operation unit that predicts a predicted remaining amount y when nothing is transferred to the master station at the end of the next frame. is there.

Next, the operation will be described.
At the end of the frame, the remaining amount b of the FIFO unit 7 is detected, and the inflow amount x is measured. The prediction calculation unit 24 predicts a predicted remaining amount y when nothing is transferred to the master station at the end of the next frame based on these two measured values. For example, when the prediction of the predicted remaining amount y is performed by applying linear prediction, a prediction coefficient is set to a, the remaining amount is set to b, and the inflow amount is set to x. Multiplexing unit 22 for multiplexing.

  The master station assigns priorities to the slave stations in the same manner as in the fifth embodiment based on the predicted remaining amount y sent from the slave station at the beginning of the frame. Every time the idle line determination unit 1 determines an idle line, the idle line is allocated to a slave station having a higher priority, thereby improving the overall transmission efficiency.

  In this reference example 6, based on the predicted remaining amount y when nothing is transferred to the master station at the end of the next frame, obtained by linear prediction from the remaining amount b of the FIFO unit 7 and the inflow amount x. At the beginning of the next frame, the priority assigned to each slave station when the idle line is transferred to the slave station is determined. It is possible to accurately determine the load amount of the above, it is possible to set a higher priority order for the information amount and the slave station having a larger load amount and to increase the bandwidth for the slave station, and to increase the information amount and the load amount. There is an effect that an access control method and an access control device capable of appropriately improving the transmission efficiency by the corresponding priorities are obtained.

Reference example 7.
In the first to sixth embodiments, only the line determined to be an idle line by the idle line determination unit 1 of the master station is transferred to another slave station. Since unnecessary traffic occurs due to idle cells during the determination time, transmission efficiency may be reduced.

  In the sixth embodiment, the remaining amount of the FIFO unit 7 of the slave station at the end of the next frame can be predicted. Therefore, in the seventh embodiment, the allocation of the TDMA slot is changed using only the predicted remaining amount. To improve transmission efficiency.

FIG. 12 is a block diagram illustrating a main configuration of a master station and a slave station of an access control device to which the access control method of the reference example 7 is applied. 12, parts that are the same as or correspond to those in FIG. 11 are given the same reference numerals, and descriptions thereof are omitted. In FIG. 12, reference numeral 21 denotes a remaining amount monitoring unit at the end of a frame, 23 denotes an inflow amount monitoring unit (inflow amount detecting means), and 25 denotes a remaining amount prediction value from the slave station received by the remaining amount extraction comparing unit 20. A TDMA slot information generator for generating TDMA slot information, and a selector 26 for selecting either the TDMA slot information generated by the TDMA slot information generator 25 or the TDMA slot information generated by the pre-assigned TDMA slot information generator 2. Reference numeral 4a denotes either the first slot information generated and set by the pre-assigned TDMA slot information generator 2 selected by the selector 26 or the second slot information generated by the slot information generator 25. A multiplexing unit that broadcasts to each of the slave stations.
The configuration of the slave station is exactly the same as that of the sixth embodiment.

Next, the operation will be described.
The remaining amount extraction comparing section 20 of the master station receives the predicted remaining amount value sent from the slave station, and the TDMA slot information generating section 25 generates TDMA slot information from the predicted remaining amount value. FIG. 13 shows an example of this algorithm.

In FIG. 13, assuming that the pre-assignment value of the n-th slave station is a _n and the predicted remaining amount value of the n-th slave station is x _n , the condition of step ST121 is not satisfied, that is, the total of the predicted remaining amount is If the estimated remaining amount is the number of allocated TDMA slots when the total number of TDMA slots is smaller than the total number, the unallocated slots exist and the TDMA slots remain. Therefore, it is necessary to increase the predicted remaining amount value in step ST122 to determine the TDMA slot allocation value. When step ST121 is satisfied, that is, when the total predicted remaining amount is larger than the total number of TDMA slots, it is necessary to determine the TDMA slot allocation quantity by subtracting the predicted remaining amount. FIG. 14 shows an example of a method of increasing and decreasing TDMA slots from these predicted remaining values.

  FIG. 14 shows three methods. First, in the first method, in the case of an increase, the number of time slots to be increased is divided by the number n of active slave stations, that is, y / n is allocated to each subscriber to increase the number of slots. In the case of the decrease, similarly, the number of slots of each slave station is decreased by y / n.

The second method is to sequentially select slave stations to be increased or decreased for each frame, and FIG. 15 shows an example of an algorithm for this increase. In Figure 15, first defines the amount Y to be increased in step ST124, and the predicted remaining amount x _n of the n-th subscriber initial value x _'n of TDMA slot allocation amount at step ST125. In the determination of step ST126, Y is zero or less, i.e. if the number should be increased slot is eliminated, and ends the TDMA slot allocation amount as x _'n in step ST128. If Y is larger than zero, the process proceeds to step ST127, and the number of slots is increased by the maximum increment c per slave station in which the slots of the slave stations of the corresponding numbers are defined in advance by the chain shown in FIG. This operation is continued until Y becomes zero. When Y approaches zero and becomes smaller than the maximum increase amount c, the increase amount is not the maximum increase amount c but the number of slots increases by the remaining amount of Y. This is expressed by a processing expression shown in step ST127. Thus Y line is increased to the slave station number order until zero, it determined the assigned number x _'n of TDMA slots.

FIG. 16 shows an example of an algorithm for reducing the number of slots in the second method in FIG. In FIG. 16, the value of the number of slots Y to be decreased is represented by the processing equation of step ST129 since the sum of the predicted remaining amount is larger than the sum of the pre-assigned values. In step ST126, if Y is larger than zero, the assigned band is reduced to zero in the order determined by the slave stations. The value of Y is small, if it is smaller than predicted remaining amount x _'K number of slots is reduced by Y.

  The first method and the second method in FIG. 14 are configured as described above, and the increase and decrease in the number of slots of all slave stations are considered to be equal on average. If they are almost equal, they will be assigned without unfairness to the slave station.However, if the pre-assigned value changes significantly and the usage fee is set by the pre-assigned value, the number of slots will be regardless of the pre-assigned value. It is not preferable because it can be changed.

The third method solves this drawback. FIG. 17 shows an example of the algorithm of the third method when the bandwidth is increased. The algorithm shown in FIG. 17 has a configuration similar to that of FIG. The difference, in step ST125 in FIG. 15, by adding a definition of the difference D _n of the pre-assigned value of each slave station as in step ST131 in FIG. 17 and the prediction residual. If the number of allocated slots still needs to be increased in step ST126 (when Y is larger than zero), in step ST132, the smallest D _n defined above, that is, the smallest amount as compared with the pre-assigned value, is allocated. A process of increasing the number of slots in the slave station by "1" is performed, and this process is repeated Y times in total, and all slots are allocated to each slave station.

FIG. 18 shows an example of a case where the bandwidth is reduced in the algorithm of the third method. In the figure, as in the case of the second method, the amount of band reduction is represented by step ST129. Compared to the case of increasing the band in FIG. 17, when it is necessary to reduce the number of allocated slots in step ST126 (when Y is larger than zero), the largest D _n defined earlier in step ST134, that is, the pre-assignment, A process of reducing the number of slots of the slave station to which the largest amount is assigned by one compared with the value is reduced by "1", and furthermore, this process is repeated Y times in total, and all slots are assigned to each slave station. It has become.

  Returning to FIG. 12, the information on the number of TDMA slots determined by estimating the buffer amount in the slave station by such various methods is selected and controlled by the selection unit 26 as soon as it is determined.

  FIG. 19 shows an example of the contents of this selection control. FIG. 19 assumes a case where an uplink signal from a slave station to a master station and a downlink signal from the master station to a slave station have logically different transmission paths. In addition, there are a plurality of slave stations and the arrangement positions are various, and the distance between the slave station and the master station is different, but the transmission timing of the slave stations at other close positions is determined based on the transmission phase of the slave station at the farthest place. Transmission control for delaying is known. In FIG. 19, the above method is assumed and the timing of the farthest slave station is described as a representative.

  In FIG. 19, reference numeral 140 denotes a transmission timing in a child station uplink, 141 denotes a reception timing in a parent station uplink, 142 denotes a transmission timing in a parent station downlink, and 143 denotes a reception timing in a child station downlink.

  Here, the notification timing of TDMA slot information will be described. In FIG. 19, at time T1, the predicted remaining amount counted in the slave stations up to that time is sequentially notified for the number of slave stations. Assuming that the time required for the notification for the number of slave stations is WS1 and the delay time of the transmission path is S2, the master station finishes receiving these at time T4 after a lapse of (S1 + S2) time from time T1. At T4, the reception of the predicted remaining amount from all the slave stations ends. Thereafter, in the period S3, the TDMA slot allocation is determined by the algorithm shown in FIG. 13 described above, and the determined information is distributed to each slave station at the time T5, or the TDMA slot information is sequentially transferred after the time T5. Each slave station receives this, and from time T6, the slave station transfers information in the uplink direction according to the TDMA slot assignment value.

  According to this algorithm, in the uplink transmission from the slave station, information cannot be transferred using the TDMA slot determined based on the estimated remaining amount at times T1 to T6. As a result, the operation of the selecting unit 26 in FIG. 12 is such that, at times T1 to T6, the transfer is performed according to the pre-assignment information determined in advance in the pre-assigned TDMA slot information generating unit 2, and at other times, the TDMA by the above algorithm The TDMA slot information generated by the slot information generator 25 is selected.

  As described above, in the seventh embodiment, the idle channel determination is performed by changing the TDMA slot allocation using the predicted remaining amount of information to be transmitted from the FIFO unit 7 of the slave station at the end of the next frame. To eliminate the time required for the determination of the idle line, eliminate unnecessary traffic caused by idle cells during the idle line determination time, and obtain an access control method and an access control device capable of avoiding a decrease in transmission efficiency. .

Reference Example 8.
In the reference example 7, although the inflow amount monitor unit 23 is provided in the configuration of FIG. 12 and the predicted remaining amount y determined by the equation, y = a · x + b is used as the predicted remaining amount, the reference example 6 uses the predicted remaining amount y. It is also possible to introduce exactly the same algorithm as in the above-described reference example 7 by using the calculated result of only the remaining amount as the estimated remaining amount. In this case, although the accuracy of the predicted value is slightly deteriorated as compared with Reference Example 7, the inflow amount monitor unit 23 is not required, and the circuit scale can be reduced.
FIG. 20 is a block diagram illustrating a main configuration of a master station and a slave station of an access control device to which the access control method of Reference Example 8 is applied. 20, parts that are the same as or correspond to those in FIG. 12 are given the same reference numerals, and descriptions thereof will be omitted. In FIG. 20, reference numeral 25 denotes a TDMA slot information generation unit according to the method (1), (2), (3), or (4) described in Reference Example 5, and reference numeral 27 denotes the residual amount detected by the frame end residual amount monitoring unit 21. A prediction calculation unit that predicts the remaining amount of information remaining in the slave station at the end of the next frame based on the amount.

  In the eighth embodiment, the access control method and the access control device which can reduce the circuit scale by eliminating the inflow amount monitoring unit 23 in the slave station are obtained.

Reference Example 9.
FIG. 21 is a block diagram illustrating a main configuration of a master station and a slave station of an access control device to which the access control method according to the ninth embodiment is applied. In FIG. 21, the same or corresponding parts as those in FIG. 1 are denoted by the same reference numerals, and description thereof is omitted. In FIG. 21, reference numeral 28 denotes an idle line storage unit for storing the number of an idle line when the idle line determination unit 1 determines an idle line; This is a TDMA slot information conversion unit that changes the allocation of the allocation slot generated by the assignment TDMA slot information generation unit 2 to another line that is not determined to be an idle line.

Next, the operation will be described.
When the idle line determination unit 1 determines an idle line, the line number is stored in the idle line storage unit 28, and the pre-assigned capacity of the idle line is transferred to another non-idle line and distributed by the TDMA slot information conversion unit 30. Is done.

As a first method of distributing the pre-assigned capacity of the idle line in this case, there is a method of securing a fixed amount as the minimum capacity and equally distributing the remaining capacity to other non-idle lines.
As a second method, there is a method of securing a fixed amount as a minimum capacity and distributing the remaining capacity in proportion to the preassign value of another non-idle line.

FIG. 22 is an explanatory diagram showing the first method. In FIG. 22, reference numeral 31 indicates a state in which respective values are indicated on the lines A to D as the pre-assignment capacity. Reference numeral 32 denotes the capacity of the lines A to D after the slot information conversion. Now, when the line A is determined to be an idle line, when the minimum capacity is set to 2, the line capacity of the line number A becomes 2. Of the pre-assigned capacity of the line A, twelve are equally distributed to the other lines B, C, and D, and each is increased by four.
Thereafter, when information from the slave station arrives on the line A and it is determined that the line is not idle, the capacity returns to the original allocated capacity as indicated by 31.
The first method is characterized in that when there is an unused line, the remaining pre-assigned capacity excluding the minimum capacity of the line is evenly distributed to other lines, so that the increased bandwidth is set to be increased fairly. .

FIG. 23 is an explanatory diagram showing the second method. In FIG. 23, reference numeral 33 denotes the capacity of the lines A to D after the slot information conversion.
When the line A is determined to be an idle line, and when the minimum capacity is set to 2, the capacity of the line A becomes 2 as in the first method. The remaining capacity 12 of the pre-assigned capacity 14 of the line A except for the minimum capacity 2 becomes 33 in proportion to the pre-assigned capacities 6, 12, and 18 assigned to the other B, C, and D lines, respectively. As shown, the capacity of the line A is increased by a minimum capacity of 2, the capacity of the line B is increased by 4, and the capacity of the line C is increased by 6.
In the second method, when there is a line that is not used, it is proportionally distributed to other lines, so that in the case where charging is performed according to the pre-assignment band, an increase band can be set according to the charging amount. It has the feature.

  As described above, in the ninth embodiment, the access control method and the access control apparatus which can improve the transmission efficiency for information having a very long idle period such as computer communication by using any of the above methods are disclosed. There is an effect that can be obtained.

Embodiment 1 FIG.
FIG. 24 is a block diagram showing a main configuration of a master station and slave stations of an access control device to which the access control method according to Embodiment 1 of the present invention is applied. In FIG. 24, reference numeral 4b denotes a multiplexing section (master station side transmitting means) for generating and multiplexing the time lot allocation information of the slave stations to downlink information and distributing and transmitting the information to each slave station; The inflow amount receiving unit 35 for periodically receiving the inflow amount of information per unit time, which is constituted by a FIFO or the like which stores the information amount to be transmitted by a plurality of slave stations along with the slave station numbers fairly. The common queue (inflow amount storing means) 36 is an allocation information generating section (slot allocation information generating means) for generating allocation information of time slots by the number of stored information in the order of child stations stored in the common queue 35. It is.
Reference numeral 5 denotes the TDMA slot information receiving unit shown in the above-mentioned Reference Examples 1 and 5, 6, 7, 8, and 9, 6a denotes a delay unit (delay means), 7 denotes a FIFO unit, and 22a denotes a multiplexing unit on the slave station side. (Slave station inflow amount transmission means, station side transmission means) and 23 are the inflow amount monitoring units shown in Reference Examples 6 and 7.

Next, the operation will be described.
FIG. 24 (b) shows the configuration of each slave station. In the slave station, information to be transmitted to the master station, which is input to the FIFO unit 7, is monitored by the inflow amount monitor unit 23 at regular intervals. The inflow amount thus added is added to a part of the transfer information to the master station and transferred to the master station.

  In the master station, the inflow amount receiving section 34 receives information such as the inflow amount from a plurality of slave stations, and stores information such as the numbers of the respective slave stations and the inflow amount in the common queue 35 in order. The allocation information generation unit 36 generates the time lot allocation information of the slave station in the order written in the common queue based on the information on the inflow amount, and the multiplexing unit (master station side transmission means) 4b downloads the time lot allocation information. It is multiplexed with information and distributed and transmitted to each slave station.

  In each slave station, the pre-assigned TDMA slot information receiving unit 5 receives this time slot allocation information, delays the transmission timing by the delay unit 6a until the time slot to be transmitted by each slave station arrives, and sets the FIFO unit 7 Read the information stored in.

  As described above, according to the first embodiment, in a state where a large amount of data is accumulated in the FIFO units in a plurality of slave stations, the number of assignments in the common queue 35 in the master station is larger than the generation cycle of the allocation information. In this state, there is a feature that the use efficiency of the transmission line is 100%, and the access control method and the access control device that improve the use efficiency when the transmission line is congested are obtained. There is.

Embodiment 2 FIG.
In the first embodiment, there is an advantage that the efficiency is improved at the time of congestion. On the other hand, in a state where the use of the transmission line is small, the information to be transmitted to the newly generated master station is based on the amount of inflow into the FIFO unit. , And transmission becomes possible after the allocation information has been sent to each slave station, so that it takes time until the transmission and the use efficiency of the transmission path is reduced.
In the second embodiment, when the use of the transmission line is small and there is no information to be used for the time slot allocation, the time slots are evenly allocated to the slave stations. To avoid a decrease in usage efficiency.

FIG. 25 is a block diagram showing a main configuration of a master station and slave stations of an access control device to which the access control method according to Embodiment 2 of the present invention is applied. In FIG. 25, the same or corresponding parts as those in FIG. In FIG. 25, reference numeral 37 denotes an empty detection unit for detecting that no information is accumulated in the common queue 35, and reference numeral 38 denotes an equal allocation signal generation for generating an equal allocation signal for equally allocating a time slot to a slave station which is powered on. The unit 39 controls the timing of the equal allocation signal output from the equal allocation signal generation unit 38 by the time from when the equal allocation signal is distributed to the slave station, when the information is transmitted from the slave station, and transferred to the master station. A delay unit for delaying, a selector 40 for selecting either the allocation information generated by the allocation information generating unit 36 or the equal allocation signal generated by the equal allocation signal generating unit 38, and 41 a valid for upstream data from the slave station An effective cell detection unit 51 for detecting that information has been inserted is an allocation information deletion unit 51.
The configuration of the slave station is the same as that of FIG.

  In the master station shown in FIG. 25A, when the empty detection unit 37 detects that there is no allocation information to be generated from the contents of the common queue 35, the equal allocation signal generation unit 38 sends a signal to the slave station that is powered on. An allocation signal is generated evenly, and even when information is not accumulated in the common queue 35, information transmission in the down direction is performed. The information transferred from the slave station in accordance with the allocation signal from the equal allocation signal generation unit 38 is based on the timing at which the equal allocation signal output from the equal allocation signal generation unit 38 is transferred by the delay unit 39 to the information from the slave station. Is delayed until. When the valid cell detecting unit 41 detects that the information transmitted according to the equal allocation signal of the equal allocation signal generating unit 38 is a valid cell, the allocation information deleting unit 51 writes the information already written in the common queue 36. It has an allocation information deletion function for reducing the amount of information to be transmitted by one of the slave station numbers to be transmitted.

  Since this embodiment is configured as described above, it is not clear from which slave station the information to be transmitted in the upstream direction may be transmitted, that is, there is information for generating allocation information in the common queue 35. If not, by generating the allocation information equally for the slave stations, the use efficiency of the transmission path can be improved even if the information of each slave station does not accumulate much. Since the information transmitted from the slave station in accordance with the equal allocation signal is already notified to the master station in the sense of slot reservation and stored in the common queue, the information of the already allocated common queue is transmitted. By performing the rewriting that only the number of channels is reduced, it is possible to obtain an access control method and an access control apparatus that can secure more uplink channels for other slave stations and can further effectively use a transmission path. effective.

Embodiment 3 FIG.
Each block in each of the above embodiments may be configured by hardware or realized by software.

FIG. 7 is a block diagram illustrating main parts of a master station and a slave station of the access control device to which the access control method of Reference Example 1 is applied. 9 is a flowchart illustrating an algorithm for creating a conversion table indicating a transfer relationship of an access control device to which the access control method of Reference Example 1 is applied. FIG. 9 is an explanatory diagram showing an example of a chain configuration of an access control device to which the access control method of Reference Example 1 is applied and a conversion table. FIG. 11 is a block diagram illustrating a main part of a master station and a slave station of an access control device to which the access control method of Reference Example 2 is applied. FIG. 13 is a block diagram illustrating a main part of a master station and a slave station of an access control device to which the access control method of Reference Example 3 is applied. FIG. 13 is a block diagram illustrating a main part of a master station of an access control device to which an access control method according to a reference example 4 is applied. FIG. 13 is a block diagram illustrating each configuration for realizing a function of detecting a highest load line by a highest load line detection unit of the access control device to which the access control method according to the reference example 4 is applied. FIG. 13 is a block diagram illustrating each configuration for realizing a function of detecting a highest load line by a highest load line detection unit of the access control device to which the access control method according to the reference example 4 is applied. FIG. 13 is a block diagram illustrating each configuration for realizing a function of detecting a highest load line by a highest load line detection unit of the access control device to which the access control method according to the reference example 4 is applied. FIG. 18 is a block diagram illustrating main parts of a master station and a slave station of an access control device to which the access control method of Reference Example 5 is applied. FIG. 18 is a block diagram illustrating main parts of a master station and a slave station of an access control device to which an access control method according to a reference example 6 is applied. FIG. 19 is a block diagram illustrating a main part of a master station and a slave station of an access control device to which an access control method according to a reference example 7 is applied. 16 is a flowchart illustrating an algorithm for generating TDMA slot information from a predicted remaining amount value in an access control device to which the access control method of Reference Example 7 is applied. FIG. 19 is an explanatory diagram showing a method of increasing and decreasing a band in an access control device to which the access control method of Reference Example 7 is applied. 16 is a flowchart illustrating an algorithm when the bandwidth is increased in the access control device to which the access control method of Reference Example 7 is applied. 16 is a flowchart illustrating an algorithm when the bandwidth is reduced in the access control device to which the access control method of Reference Example 7 is applied. 16 is a flowchart illustrating an algorithm when the bandwidth is increased in the access control device to which the access control method of Reference Example 7 is applied. 16 is a flowchart illustrating an algorithm when the bandwidth is reduced in the access control device to which the access control method of Reference Example 7 is applied. FIG. 19 is a sequence diagram showing a timing of notifying TDMA slot information in an access control device to which the access control method of Reference Example 7 is applied. FIG. 21 is a block diagram illustrating a main part of a master station and slave stations of an access control device to which an access control method according to a reference example 8 is applied. FIG. 21 is a block diagram illustrating a main part of a master station of an access control device to which the access control method of Reference Example 9 is applied. FIG. 19 is an explanatory diagram showing a first method of distributing preassigned capacity of an idle line in an access control device to which the access control method of Reference Example 9 is applied. FIG. 21 is an explanatory diagram showing a second method of distributing the preassigned capacity of the idle line in the access control device to which the access control method of Reference Example 9 is applied. FIG. 2 is a block diagram illustrating main parts of a master station and a slave station of the access control device to which the access control method according to the first embodiment of the present invention is applied. FIG. 9 is a block diagram illustrating a main part of a master station and slave stations of an access control device to which an access control method according to a second embodiment of the present invention is applied. 1 is a configuration diagram showing a subscriber line to which a conventional access control method and device are applied.

Explanation of reference numerals

  1 Idle line determination unit, 1a idle line determination unit, 2 pre-assigned TDMA slot information generation unit, 3, 3a, 30 TDMA slot information conversion unit, 4 multiplexing unit, 4a multiplexing unit, 4b multiplexing unit (master station side) Transmission means), 6, 6a delay unit (delay means), 7 FIFO, 20 remaining amount extraction comparison unit, 21 frame end remaining amount monitor unit, 22 multiplexing unit, 22a multiplexing unit (child station side inflow amount transmission unit) , Slave station side transmission means), 23 inflow amount monitor section (inflow amount detection means), 24, 27 prediction operation section, 25 TDMA slot information generation section, 26 selection section (selection section), 35 common queue (inflow amount storage section) ), 36 allocation information generating section (slot allocation information generating means), 40 selector.

Claims (4)

In an access control method for connecting a master station and a plurality of slave stations via a transmission line and performing time-division digital communication from the slave station to the master station using a slot assigned to each slave station,
An inflow amount detecting step of detecting an inflow amount of information flowing into the slave station;
An inflow amount storing step of sequentially storing information about the inflow amount detected in the inflow amount detection step together with the identification information of the slave station;
A slot allocation information generating step of generating slot allocation information of a slot to be allocated to each slave station according to the order based on the information on the inflow amount stored in the inflow amount storing step;
Based on the slot allocation information for each of the slave stations generated by the slot allocation information generating step, each of the slave stations knows its own slot allocated to itself, and transmits information to be transmitted by the own slot. An access control method, comprising: a transmitting step of transmitting.   A delay step of delaying transmission timing until a slot carrying information to be transmitted arrives based on the slot allocation information for each slave station generated in the slot allocation information generation step. The access control method according to claim 1. An access control device that connects a master station and a plurality of slave stations via a transmission line such as an optical fiber and performs time-division digital communication from the slave station to the master station using a slot allocated to each slave station.
An inflow amount detecting means for detecting an inflow amount of information flowing into the slave station;
A slave-station-side inflow-amount transmitting unit that multiplexes information about the inflow amount detected by the inflow-amount detection unit from each of the slave stations to the master station according to slot allocation information; Inflow amount storage means for sequentially storing information on the inflow amount sent to the master station together with the identification information of the slave station,
Based on the information about the inflow amount stored by the inflow amount storage means, based on the information about the inflow amount, slot allocation information generating means for generating the slot allocation information of the slot to be allocated to each slave station according to the order,
Master station-side transmitting means for multiplexing the slot assignment information generated by the slot assignment information generating means from the master station to each of the slave stations and transmitting the multiplexed information;
Based on the slot allocation information sent to each of the slave stations by the master station-side transmitting means, each of the slave stations knows its own slot assigned to itself, and determines the information to be transmitted by the own slot. An access control device comprising: a slave station side transmitting means for transmitting.   Based on the slot assignment information for each slave station generated by the slot assignment information generation means, each of the slave stations includes a delay means for delaying transmission timing until a slot carrying information to be transmitted arrives. 4. The access control device according to claim 3, wherein:

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