JP2017034417A - Communication control method, communication system and communication control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve improvement in stability of communication adapted for an interfered state of a receiver and equalization of transmission opportunities of each transmitter, in order to control the transmitters such that the number of remaining interference waves removable by receivers are multiply assigned to users.SOLUTION: A receiver detects the number of interference waves received from another system. A communication control device acquires interference relation information about an interference relation between a transmitter and a receiver. On the basis of an interference wave state parameter corresponding to an interfered state of the receiver, the receiver or communication control device calculates a comparison target value. On the basis of the number of interference waves and the interference relation information, the communication control device calculates the number of remaining removable interference waves for each transmitter to be determined, in order from a transmitter fewer in past transmission opportunities. If the condition is satisfied in which the number of remaining removable interference waves for each receptor determined to receive and the number of remaining removable interference waves of the receptor that is a destination for a transmitter to be determined are both equal to or greater than the comparison target values, transmission is permitted.SELECTED DRAWING: Figure 12

Description

  The present invention relates to a communication control method, a communication system, and a communication control apparatus.

There is known a radio communication system that performs communication by performing signal multiplexing by TDMA (Time Division Multiple Access). Such a wireless communication system is often composed of a control station, a base station (fixed station), and a terminal (mobile station).
For example, the control station and the base station transmit and receive control messages via wired or wireless communication. Also, the control station and the terminal perform control message transmission / reception through direct wireless communication or indirect wireless communication via the base station.

The control station controls the transmission of the transmitter included in the base station or terminal by notifying the transmission permission time to the base station or terminal, for example, by a control message.
In general, when signals output as radio waves collide (interfere) with each other, signals cannot be received normally. Therefore, the control station controls the transmission of the transmitter so that signals do not collide with each other at the receiver.

On the other hand, techniques for compensating for interference have been proposed. As an example, a configuration is known in which communication is performed by extracting a desired signal by removing an interference wave received by a receiver using a blind type adaptive array antenna technique (see, for example, Non-Patent Document 1). ).
The removal of interference waves by the blind adaptive array antenna technology is generally used to remove interference waves received from other systems. In the blind adaptive array antenna technology, the number of interference waves that can be removed may be limited depending on the hardware configuration. Specifically, the upper limit of the number of interference waves that can be removed simultaneously by the blind adaptive array antenna technology is determined according to the number of antennas, and the number of interference waves that can be removed by one less than the number of antennas. It becomes the upper limit of.

Maruta, Masuno, Nakato, Sugiyama, “Blind interference suppression using eigenvector beamspace CMA adaptive array with subcarrier transmission power control” IEICE Tech. Report, March 2014, vol 113, no. 456, RCS2013-343 , Pp. 223-228

  The number of interference waves received from other systems varies depending on the environment. For this reason, depending on the environmental conditions, there may be a surplus in the number of interference waves that can be removed by the receiver having the interference compensation function. The state where the remainder of the number of interference waves that can be removed is a state where the number of interference waves is smaller than the upper limit of the number of interference waves that can be removed by the receiver.

The frequency utilization efficiency can be improved by performing user multiplexing in which the excess of the number of removable interference waves generated as described above is assigned to the communication of a plurality of users. However, as described above, there is an upper limit on the number of interference waves that can be removed. For this reason, if user multiplexing is performed in a state where the upper limit of the number of interference waves that can be removed is exceeded, there are interference waves that cannot be removed, and the communication state in the communication system becomes unstable.
In addition, when performing communication allocation as described above, depending on the state of interference received by the receiver that is the destination of the transmitter, there is a possibility that a transmitter that easily obtains a transmission opportunity and a transmitter that hardly obtains a transmission opportunity may occur. There is. If the difference in transmission opportunity between such transmitters is large, the service quality experienced by the user may be significantly reduced, for example, the user experience may be reduced.

  In addition, the situation in which the receiver is receiving interference varies from receiver to receiver, and also varies with time in the same receiver. It is required to appropriately perform user multiplexing according to such time variation.

  In view of the above circumstances, the present invention provides a communication system adapted to a situation in which the receiver is receiving interference when the transmitter is controlled so as to allocate a surplus of the number of interference waves that can be removed by the receiver to user multiplexing. The purpose is to improve stability and equalize the transmission opportunities of each transmitter.

  One aspect of the present invention is a communication control method in a communication system including a communication control device, a plurality of transmitters and a plurality of receivers that perform wireless communication, and the receiver is a system other than the communication system. An interference wave number detecting step of detecting an interference wave number received from the receiver, an interference relationship information acquiring step in which the communication control device acquires interference relationship information indicating an interference relationship in the transmitter and the receiver, and the receiver or the communication A comparison target value calculation step in which the control device calculates a comparison target value based on an interference wave condition parameter that changes according to the state of the interference wave received by the receiver, and the communication control apparatus transmits a transmission with a small number of past transmission opportunities. It is determined whether transmission should be permitted in order from the machine, and received for each transmitter to be determined when the transmitter to be determined transmits. Is calculated based on the number of interference waves and the interference relation information, and the destination is a transmitter that has already been determined to permit transmission. When the condition that both the number of residual interference waves that can be removed for each receiver and the number of residual interference waves that can be removed from the receiver that is the destination of the determination target is greater than or equal to the comparison target value is satisfied It is a communication control method that includes a transmission permission / inhibition determination step that determines that transmission should be permitted and determines that transmission should not be permitted when the above condition is not satisfied.

  One aspect of the present invention is the communication control method described above, wherein the comparison target value calculating step sets a reception error rate based on the number of slots that have failed to be received among the slots transmitted to the receiver to the interference wave. The comparison target value is calculated by acquiring or obtaining a constant as a situation parameter and adding or subtracting a constant according to the comparison result between the reception error rate and a predetermined threshold to the comparison target value so far.

  One aspect of the present invention is the communication control method described above, wherein the comparison target value calculation step is detected for each allocation slot allocated to the receiver in a certain period before the time point when the current interference wave number is detected. A maximum value within a period, which is a maximum value of the number of interference waves to be detected, and a current interference wave number detected corresponding to the time point to be detected are acquired as the interference wave status parameter, and the current interference is calculated from the maximum value within the period. The comparison target value is calculated by subtracting the wave number.

  One aspect of the present invention is the communication control method described above, wherein the comparison target value calculating step is performed for each of a plurality of assigned slots assigned to the receiver in a predetermined period before the time point when the current interference wave number is detected. The frequency-corresponding maximum value among the slot-unit interference wave number maximum values obtained by excluding the slot-unit interference wave number maximum value that is not more than a predetermined appearance frequency from among the slot-unit interference wave number maximum values that are the maximum value of the detected interference wave number, and the time point of the detection Is obtained as the interference wave condition parameter, and the comparison target value is calculated by subtracting the current interference wave number from the frequency-corresponding maximum value.

  One aspect of the present invention is the communication control method described above, wherein the comparison target value calculating step includes the number of interference waves received from another system when the receiver is receiving and the number of interference waves received from the other system when not being received. Further, the number of interference sources having a collision avoidance function in another system is obtained as the interference wave condition parameter, and the comparison target value is calculated by further subtracting the number of interference sources.

  One aspect of the present invention is the communication control method described above, wherein the comparison target value calculating step is performed for each of a plurality of assigned slots assigned to the receiver in a predetermined period before the time point when the current interference wave number is detected. Detected in accordance with the estimated slot unit interference wave maximum value in the next assigned slot, which is estimated based on the appearance pattern of the slot unit interference wave maximum value which is the maximum value of the detected interference wave number, and the detection time point The current interference wave number is acquired as the interference wave state parameter, and the comparison target value is calculated by subtracting the current interference wave number from the estimated slot-unit interference wave number maximum value.

  One embodiment of the present invention is a communication system including a communication control device, a plurality of transmitters and a plurality of receivers that perform wireless communication, and the number of interference waves received from a system other than the communication system in the receiver. An interference wave number detection unit that detects interference relationship information acquisition unit that acquires interference relationship information indicating an interference relationship in the transmitter and the receiver, and the receiver or the communication control device. A comparison target value calculation unit that calculates a comparison target value using an interference wave status parameter that changes according to the status of the interference wave received by the receiver, and in the communication control device, in order from the transmitter with the least number of past transmission opportunities This is used to determine whether or not transmission should be permitted. For each transmitter to be determined, the receiver can be removed when the transmitter to be determined transmits. The number of interference waves remaining, which is the remaining number of interference waves, is calculated based on the interference wave number and the interference relationship information, and for each receiver to which the transmitter that has already been determined to permit transmission Transmission is permitted when the condition that the remaining number of remaining interference waves and the remaining number of remaining interference waves of the receiver that is the destination of the determination target transmitter are equal to or greater than the comparison target value is satisfied. And a transmission availability determination unit that determines that transmission should not be permitted when the condition is not satisfied.

  One embodiment of the present invention is a communication control apparatus in a communication system including a plurality of transmitters and a plurality of receivers that perform wireless communication, and is an interference wave detected by the receiver and received from a system other than the communication system. An interference wave number acquisition unit for acquiring the interference wave number detected by the receiver for the number of interferences, an interference relationship information acquisition unit for acquiring interference relationship information indicating an interference relationship in the transmitter and the receiver, and interference received by the receiver The comparison target value acquisition unit that acquires the comparison target value calculated using the interference wave status parameter that changes according to the wave status, and the transmitter that has few previous transmission opportunities should be allowed to transmit in order. For each transmitter to be judged, if the transmitter to be judged transmits, it is the remaining number of interference waves that can be removed by the receiver. The number of remaining interference waves is calculated based on the number of interference waves and the interference relation information, and the number of remaining removable interference waves for each receiver to which a transmitter that has already been determined to be permitted to transmit, It is determined that transmission should be permitted when the condition that both of the remaining releasable interference waves of the receiver that is the destination of the transmitter to be determined is equal to or greater than the comparison target value, and the condition is satisfied And a transmission control unit that determines that transmission should not be permitted when there is no communication.

  According to the present invention, in controlling the transmitter so that the surplus of the number of interference waves that can be removed by the receiver is allocated to user multiplexing, the stability of communication adapted to the situation in which the receiver is receiving interference is improved. The effect that equalization of the transmission opportunity of each transmitter is realized is obtained.

It is a figure which shows the example of a whole structure of the communication system in 1st Embodiment. It is a figure which shows the structural example of the base station in 1st Embodiment. It is a figure which shows the structural example of the terminal device in 1st Embodiment. It is a figure which shows the structural example of the control station in 1st Embodiment. It is a figure which shows typically the example of the content of the interference related information in 1st Embodiment. It is a figure which shows typically the example of the content of the interference wave number information in 1st Embodiment. It is a figure which shows the example of the content of the removable maximum interference wave number information in 1st Embodiment. It is a figure which shows the example of the content of the comparison object value information in 1st Embodiment. It is a flowchart which shows the example of a process sequence which the receiver in 1st Embodiment performs regarding detection and notification of an interference wave number. It is a flowchart which shows the example of a process sequence which the receiver in 1st Embodiment performs regarding calculation and notification of a comparison object value. It is a flowchart which shows the example of a process sequence which the control station in 1st Embodiment performs. It is a figure which shows the example of the process sequence which the control station in 1st Embodiment performs for the transmission permission determination in FIG. 11, transmitter control, and transmission history information update.

<First Embodiment>
[Configuration example of communication system]
FIG. 1 shows an example of the overall configuration of a communication system in the present embodiment. As shown in the figure, the communication system in the present embodiment includes a base station 100 (an example of a communication device), terminal devices 200-1, 200-2, 200-3 (an example of a communication device), and a control station 300. (An example of a communication control device).
The base station 100 and the control station 300 are fixed stations, and the terminal devices 200-1, 200-2, and 200-3 are mobile stations.

In the following description, the terminal devices 200-1, 200-2, and 200-3 will be referred to as the terminal device 200 unless otherwise distinguished. In the figure, an example in which three terminal devices 200-1, 200-2, and 200-3 are provided in the communication system is shown, but the number of terminal devices 200 provided in the communication system is not particularly limited.
In addition, although one base station 100 is shown in the figure, a plurality of base stations 100 may be provided in the communication system.

The base station 100 and the control station 300 perform communication by transmission / reception of light or electrical signals by wired connection, or wireless communication. In addition, the terminal device 200 and the control station 300 perform wireless communication via the base station 100.
Note that the terminal device 200 and the control station 300 may directly perform wireless communication without using the base station 100. However, in the following description, a case where the terminal device 200 and the control station 300 perform wireless communication via the base station 100 is taken as an example.
Moreover, the case where TDMA (Time Division Multiple Access) is applied to radio | wireless communication between the terminal device 200 and the control station 300 is mentioned as an example.
However, the wireless communication method applied in the present embodiment is not limited to TDMA, and may be, for example, another time division multiple access method. Moreover, this embodiment is applicable also to the system of the wireless communication by frequency division multiple access, for example.

The base station 100 includes a transmitter 101 and a receiver 102. The transmitter 101 performs transmission under wireless communication. The receiver 102 performs reception under wireless communication.
“T00” is assigned to the transmitter 101 as a transmitter ID that uniquely indicates the transmitter in the communication system. “R00” is assigned to the receiver 102 as a receiver ID that uniquely indicates the receiver in the communication system.

The terminal device 200-1 includes a transmitter 201-1 and a receiver 202-1. The transmitter 101 performs transmission under wireless communication. The receiver 102 performs reception under wireless communication.
The transmitter 201-1 is assigned “T01” as the transmitter ID. The receiver 202-1 is given “R01” as the receiver ID.

Similarly, the terminal device 200-2 includes a transmitter 201-2 and a receiver 202-2. The transmitter 201-2 is assigned “T02” as the transmitter ID, and the receiver 202-2 is assigned “R02” as the receiver ID.
The terminal device 200-3 includes a transmitter 201-3 and a receiver 202-3. The transmitter 201-3 is assigned “T03” as the transmitter ID, and the receiver 202-3 is assigned “R03” as the receiver ID.

Hereinafter, the transmitters 201-1, 201-2, and 201-3 are referred to as the transmitter 201 unless otherwise distinguished. The receivers 202-1, 202-2, and 202-3 are referred to as receivers 202 when not particularly distinguished.
Further, when there is no particular distinction between the transmitter 101 of the base station 100 and the transmitter 201 of the terminal device 200, they are simply referred to as a transmitter. Further, when there is no particular distinction between the receiver 102 of the base station 100 and the receiver 202 of the terminal device 200, they are simply referred to as a receiver.

[Example of base station configuration]
FIG. 2 shows a configuration example of the base station 100. The transmitter 101 in the base station 100 shown in the figure includes an external communication interface 111 and a signal transmission unit 112.
The external communication interface 111 receives a signal transmitted from the control station 300 by, for example, wired communication using an optical or electric signal or wireless communication.
The signal transmission unit 112 performs processing for transmitting a signal to the terminal device 200 through wireless communication. The signal transmission unit 112 includes a signal storage unit 1121 and a transmission control unit 1122.
The signal storage unit 1121 stores (buffers) a signal to be transmitted to the terminal device 200. The transmission control unit 1122 controls transmission of signals stored in the signal storage unit 1121.

Also, in the base station 100 of the figure, the receiver 102 includes an external communication interface 121, a signal receiving unit 122, and a notification unit 123.
The external communication interface 121 transmits a signal to the control station 300 by, for example, wired communication using optical or electrical signals, or wireless communication.
The signal receiving unit 122 performs a process of receiving a signal transmitted from the terminal device 200 through wireless communication. The signal reception unit 122 includes an interference compensation unit 1221, an interference wave number detection unit 1222, and a comparison target value calculation unit 1223.

The interference compensation unit 1221 compensates for radio wave interference received by the receiver 102 from another communication system. Specifically, the interference compensator 1221 extracts a desired signal by removing an interference wave received by the receiver 102 using a blind adaptive array antenna technique. Note that the configuration for the interference compensation unit 1221 to perform interference compensation is not limited to the blind-type adaptive array antenna technology, and other configurations for interference compensation may be employed.
The interference wave number detection unit 1222 detects the number of interference waves (interference wave number) received by the receiver 102 from another communication system (another system). The interference wave number can be detected by monitoring the state of the interference wave removal process performed by the interference compensation unit 1221.
The comparison target value calculation unit 1223 acquires a comparison target value calculation parameter. The comparison target value calculation parameter is a parameter used for calculation of the comparison target value in the present embodiment, and changes according to the state of the interference wave received by the receiver 102. In addition, the comparison target value in the present embodiment is a value (threshold value) used for comparison with the remaining number of removable interference waves of the receiver when the control station 300 determines whether transmission is possible for the transmitter. In addition, the comparison target value calculation unit 1223 calculates a comparison target value using the acquired comparison target value calculation parameter.

The notification unit 123 notifies the control station 300 of the interference wave number detected by the interference wave number detection unit 1222.
Specifically, the notification unit 123 generates an interference wave number notification message for notifying the interference wave number detected by the interference wave number detection unit 1222, and transmits the generated interference wave number notification message from the external communication interface 121 to the control station 300. Let
Further, the notification unit 123 notifies the control station 300 of the comparison target value calculated by the comparison target value calculation unit 1223. That is, the notification unit 123 generates a comparison target value notification message that notifies the comparison target value calculated by the comparison target value calculation unit 1223, and sends the generated comparison target value notification message from the external communication interface 121 to the control station 300. To send to.

In addition, the signal receiving unit 122 receives a signal transmitted from the terminal device 200 by radio, and transfers the received signal to the control station 300 via the external communication interface 121.
The signal received by the signal receiver 122 from the terminal device 200 and transferred to the control station 300 includes a data signal transmitted from the terminal device 200 that is the transmission source of the received signal, an interference wave number notification message, and a comparison value notification. At least one of the messages. The interference signal number notification message of the received signal indicates the interference signal number from another communication system detected by the receiver in the terminal device 200 that is the transmission source of the reception signal.

Further, the control station 300 transmits a base station transmission control message that is a control message for controlling transmission of signals by the transmitter 101. The transmitted base station transmission control message is received by the external communication interface 111 of the transmitter 101 and input to the transmission control unit 1122.
Transmission control section 1122 outputs a transmission trigger signal to signal storage section 1121 according to the transmission timing specified by the input base station transmission control message.

The signal accumulation unit 1121 transmits the accumulated signal to the destination terminal device 200 by wireless communication over a period specified by the transmission trigger signal.
The signal transmitted from the control station 300 and accumulated in the signal accumulating unit 1121 is a data signal to be received by the destination terminal device 200 and a control message that specifies the transmission timing of the transmitter 201 in the destination terminal device 200. Terminal transmission control message.

[Configuration example of terminal device]
A configuration example of the terminal device 200 will be described with reference to FIG. The transmitter 201 in the terminal device 200 in FIG. 1 includes an external communication interface 211 and a signal transmission unit 212.
The external communication interface 211 receives a data signal transmitted from the lower network 400 via wired or wireless communication.

The signal transmission unit 212 performs processing for signal transmission by wireless communication to the base station 100. The signal transmission unit 212 includes a signal storage unit 2121, a transmission control unit 2122, and a notification unit 2123.
The signal accumulation unit 2121 accumulates transmission signals to be transmitted to the base station 100. Specifically, the signal storage unit 2121 includes the data signal transferred from the external communication interface 211, the interference wave number notification message generated by the notification unit 2123, and the comparison target value notification message generated by the same notification unit 2123. A transmission signal including at least one of them is accumulated.

The transmission control unit 2122 controls transmission of signals stored in the signal storage unit 2121.
The notification unit 2123 notifies the base station 100 of the interference wave number detected by the interference wave number detection unit 2222 in the receiver 202. For this purpose, the notification unit 2123 generates an interference wave number notification message for notifying the interference wave number detected by the interference wave number detection unit 2222, and causes the signal storage unit 2121 to store the generated interference wave number notification message.
In addition, the notification unit 2123 notifies the base station 100 of the comparison target value calculated by the comparison target value calculation unit 224 in the receiver 202. For this purpose, the notification unit 2123 generates a comparison target value notification message that notifies the comparison target value calculated by the comparison target value calculation unit 224, and stores the generated comparison target value notification message in the signal storage unit 2121. Let

The receiver 202 in the terminal device 200 in FIG. 2 includes an external communication interface 221 and a signal receiving unit 222.
The external communication interface 221 transmits the data signal output from the signal discriminating unit 2224 to the lower network 400 via wired or wireless communication.

  The signal receiving unit 222 executes processing related to reception of a signal transmitted from the base station 100. The signal reception unit 222 includes an interference compensation unit 2221, an interference wave number detection unit 2222, a comparison target value calculation unit 2223, and a signal discrimination unit 2224.

The interference compensation unit 2221 performs compensation for radio wave interference received by the receiver 202 from another communication system. The interference compensation unit 2221 extracts a desired signal by removing the interference wave received by the receiver 102 from the signal of the received wave, for example, using a blind adaptive array antenna technique.
The interference wave number detection unit 2222 detects the interference wave number received by the receiver 102 from another communication system. The interference wave number detection unit 2222 outputs the detected interference wave number to the notification unit 2123 in the signal transmission unit 212 of the transmitter 201.
The comparison target value calculation unit 2223 acquires a comparison target value calculation parameter corresponding to the state of the interference wave received by the receiver 202. In addition, the comparison target value calculation unit 2223 calculates a comparison target value using the acquired comparison target value calculation parameter. The comparison target value calculation unit 2223 outputs the calculated comparison target value to the notification unit 2123.

The signal discriminating unit 2224 receives the signal received from the base station 100 via the interference compensation unit 2221 and discriminates the input signal. The signal received by the signal receiving unit 222 from the base station 100 includes at least one of a data signal and a transmission control message transmitted from the control station 300.
Therefore, the signal discriminating unit 2224 discriminates whether the signal received from the base station 100 is a data signal or a transmission control message.
The signal discriminator 2224 outputs the discriminated data signal to the external communication interface 221 when discriminating that the received signal is a data signal. As a result, the data signal is transmitted to the lower network 400.
On the other hand, when the signal discriminating unit 2224 discriminates that the received signal is a transmission control message, the signal discriminating unit 2224 outputs the discriminated transmission control message to the transmission control unit 2122 of the transmitter 201.
The transmission control unit 2122 outputs a transmission trigger signal to the signal storage unit 2121 according to the transmission timing specified by the transmission control message input from the signal discrimination unit 2224.

  The signal accumulation unit 2121 transmits the accumulated signal to the base station 100 by wireless communication over a period specified by the transmission trigger signal. As described above, the signal transmitted from the signal storage unit 2121 to the base station 100 is at least one of the data signal, the interference wave number notification message generated by the notification unit 2123, and the comparison target value notification message. And is transferred to the control station 300 via the base station 100.

[Configuration example of control station]
A configuration example of the control station 300 will be described with reference to FIG. The control station 300 in the figure includes a reception unit 301, a transmission allocation unit 302, a transmitter control unit 303, a storage unit 304, and a transmission unit 305.
The receiving unit 301 receives a signal transmitted from the base station 100 by wire or wireless.

The transmission allocation unit 302 performs transmission allocation for the transmitter 101 and the transmitter 201. The transmission allocation here is a process for determining how to allocate transmission resources to the transmitter 101 and the transmitter 201, respectively. The transmission resource allocation in the present embodiment is, for example, transmission time and slot allocation.
The transmission allocation unit 302 of this embodiment includes an interference wave number acquisition unit 321, an interference relationship information acquisition unit 322, a comparison target value acquisition unit 323, a transmission availability determination unit 324, and a transmission history information update unit 325.

The interference wave number acquisition unit 321 acquires the interference wave number detected by each of the receiver 102 in the base station 100 and the receiver 202 in the terminal device 200.
The base station 100 transmits an interference wave number notification message indicating the interference wave number detected by the receiver 102 included in the base station 100 to the control station 300. In addition, the base station 100 relays the interference wave number notification message transmitted from each terminal apparatus 200 and transmits it to the control station 300. The interference wave number notification message transmitted from the terminal device 200 indicates the interference wave number detected by the receiver 202 in the terminal device 200.

The interference wave number acquisition unit 321 inputs the interference wave number notification message transmitted from the base station 100 from the reception unit 301 as described above. The interference wave number notification message includes a receiver ID indicating the receiver 102 or the receiver 202 included in the transmission source base station 100. The interference wave number acquisition unit 321 associates the interference wave number indicated by the input interference wave number notification message with the receiver ID included in the same interference wave number notification message.
The interference wave number acquisition unit 321 stores the interference wave number associated with the receiver ID as described above in the interference state information stored in the interference state information storage unit 342 of the storage unit 304.

  The interference relationship information acquisition unit 322 acquires interference relationship information indicating the interference relationship between the transmitters 101 and 201 and the receivers 102 and 202. The interference relationship here refers to a relationship in which interference is caused when transmitters simultaneously transmit for each receiver.

The interference relationship can be specified based on the detection status of the radio wave transmitted from each transmitter in each receiver. The method for grasping the detection status of the radio wave transmitted from each transmitter in each receiver is not particularly limited, but as an example, the following method can be used in the present embodiment.
That is, a predetermined pilot signal is sequentially transmitted from each of the transmission devices, and each receiver detects whether or not the pilot signal is received. Thereby, the detection status of the radio wave transmitted from each transmitter is specified in each receiver.

In this case, the interference relationship information acquisition unit 322 instructs the base station 100 and each terminal device 200 to transmit predetermined pilot signals in an arbitrary order.
In response to the pilot signal transmission instruction, the transmitter control unit 303 generates a control message (pilot signal transmission request) instructing transmission of the pilot signal in accordance with the control of the interference relationship information acquisition unit 322, and the transmission unit 305. To the destination communication device (base station 100 or terminal device 200).

For example, a pilot signal transmission request transmitted to a certain destination communication device (base station 100 or terminal device 200) is received by the destination communication device.
When the destination communication apparatus is the base station 100, the transmitter 101 of the base station 100 transmits a pilot signal by broadcast or multicast to each terminal apparatus 200 in response to reception of the pilot signal transmission request.
When the destination communication apparatus is the terminal apparatus 200, the pilot signal transmission request is received by the receiver 202 of the terminal apparatus 200 via the base station 100, and the transmission control of the transmitter 201 is performed from the signal discriminating unit 2224. To the part 2122. When the pilot signal transmission request is transferred to the transmission control unit 2122, the transmitter 201 transmits a pilot signal to the base station 100 and each of the other terminal devices 200 by broadcast or multicast. Transmission of the pilot signal to the terminal device 200 is performed via the base station 100.
As described above, the pilot signal transmitted from one communication device (base station 100 or terminal device 200) is not necessarily all other communication devices (base station 100 or terminal device 200) due to communication distances, radio wave conditions, and the like. ) May not be reached.

When the pilot signal can be received by the base station 100, the received pilot signal is received by the receiver 102. In response to receiving the pilot signal, the receiver 102 transmits a pilot signal reception response indicating that the pilot signal has been received to the control station 300.
Further, when the pilot signal can be received by the terminal device 200, the received pilot signal is received by the receiver 202. In response to receiving the pilot signal, the receiver 202 transmits a pilot signal reception response indicating that the pilot signal has been received, to the control station 300.

According to the above description, when control station 300 transmits a pilot signal transmission request with one communication device (base station 100 or terminal device 200) as a destination, the destination communication device transmits a pilot signal to another communication device. . Then, a pilot signal reception response is returned to the control station 300 from another communication apparatus that has received the pilot signal. The returned pilot signal reception response is input by the interference relation information acquisition unit 322 of the control station 300.
That is, the interference relationship information acquisition unit 322 in the control station 300 collects the return status of the pilot signal reception response obtained for each transmission of the pilot signal after sequentially transmitting the pilot signal for each communication device. Thereby, the interference relationship information acquisition unit 322 can specify the interference relationship between the transmitters 101 and 201 and the receivers 102 and 202 in the own communication system. The interference relationship information acquisition unit 322 generates interference relationship information indicating the identified interference relationship.

FIG. 5 schematically shows a content example of interference relationship information corresponding to an example of the interference relationship of the own communication system specified by the interference relationship information acquisition unit 322.
In the figure, the presence / absence of radio wave detection is shown for each combination of the transmitters 101 and 201 and the receivers 102 and 202. In the figure, each transmitter is indicated by a transmitter ID (FIG. 1), and each of the receivers 102 and 202 is indicated by a receiver ID (FIG. 1).
In the figure, “With radio wave detection” indicates that the radio wave transmitted from the transmitter was detected by the receiver in the combination of the transmitter and the receiver associated with “With radio wave detection”. ing. Specifically, under the above-described method using a pilot signal, “with radio wave detection” is transmitted from the transmitter in a combination of a transmitter and a receiver associated with the “with radio wave detection”. This corresponds to the case where the received pilot signal is received by the receiver. Therefore, the receiver corresponding to “with radio wave detection” in this case transmits a pilot signal reception response corresponding to the pilot signal transmitted from the corresponding transmitter.
On the other hand, “no radio wave detection” indicates that the radio wave transmitted from the transmitter was not detected by the receiver in the combination of the transmitter and the receiver associated with the “no radio wave detection”. ing. Specifically, under the above-described method using the pilot signal, “no radio wave detection” is transmitted from the transmitter in the combination of the transmitter and the receiver associated with the “no radio wave detection”. This corresponds to the case where the pilot signal is not received by the receiver. Therefore, the receiver corresponding to “no radio wave detection” in this case does not transmit a pilot signal reception response corresponding to the pilot signal transmitted from the corresponding transmitter.

According to the figure, the receiver 102 (receiver ID = R00) includes a transmitter 101 (transmitter ID = T00), a transmitter 201-1 (transmitter ID = T01), and a transmitter 201-2 (transmitter). ID = T02) and transmitter 201-3 (transmitter ID = T03) indicate that radio waves transmitted from each transmitter can be detected.
That is, in the case of the receiver 102 in the same figure, when transmission is simultaneously performed from two or more of the transmitter 101 and the transmitters 101, 201-1, 201-2, and 201-3, radio wave interference occurs. Have an interference relationship.

Next, the receiver 202-1 (receiver ID = R01) can detect radio waves transmitted from the transmitter 101 (transmitter ID = T00) and the transmitter 201-1 (transmitter ID = T01). Although it is in the situation, it is indicated that the radio waves transmitted from the transmitter 201-2 (transmitter ID = T02) and the transmitter 201-3 (transmitter ID = T03) cannot be detected.
In other words, the receiver 202-1 in the same figure has an interference relationship in which radio wave interference occurs when transmission is simultaneously performed from the transmitters 101 and 201-1.

Next, the receiver 202-2 (receiver ID = R02) includes the transmitter 101 (transmitter ID = T00), the transmitter 201-1 (transmitter ID = T01), and the transmitter 201-2 (transmitter ID). = T02), the radio waves transmitted from each of the transmitters 201-3 (transmitter ID = T03) cannot be detected.
In other words, the receiver 202-2 in the figure has an interference relationship in which radio wave interference occurs when two or more of the transmitters 101, 201-1 and 201-2 are simultaneously transmitted.

Next, the receiver 202-3 (receiver ID = R03) can detect radio waves transmitted from the transmitter 101 (transmitter ID = T00) and the transmitter 201-3 (transmitter ID = T03). Although it is in the situation, it is indicated that radio waves transmitted from the transmitter 201-1 (transmitter ID = T01) and the transmitter 201-2 (transmitter ID = T02) cannot be detected.
That is, it is shown that the receiver 202-3 in the same figure has an interference relationship in which radio wave interference occurs when transmission is simultaneously performed from the transmitters 101 and 201-3.

The interference relationship information acquisition unit 322 generates (acquires) interference relationship information indicating the specified interference relationship, for example, as shown in the figure, and stores the interference state information so that the acquired interference relationship information is included in the interference status information. It can be stored in the unit 342.
The interference relationship shown in the figure is an example. Further, the interference relationship changes depending on the radio wave condition, the position of the terminal device 200 that is a mobile station, and the like. Therefore, the interference relationship information acquisition unit 322 updates the interference relationship information by causing the communication system to execute an operation for specifying the interference relationship with the transmission of the pilot signal at predetermined time intervals, for example. .

Returning to FIG. In the transmission allocation unit 302, the comparison target value acquisition unit 323 acquires the comparison target value calculated by each of the receiver 102 in the base station 100 and the receiver 202 in the terminal device 200.
The base station 100 transmits a comparison target value notification message indicating the comparison target value calculated by the receiver 102 included in the base station 100 to the control station 300. Further, the base station 100 relays the comparison target value notification message transmitted from each terminal device 200 and transmits it to the control station 300. The comparison target value notification message transmitted from the terminal device 200 indicates the comparison target value calculated by the receiver 202 in the terminal device 200.

The comparison target value acquisition unit 323 inputs the comparison target value notification message transmitted from the base station 100 as described above from the reception unit 301. The comparison target value notification message includes a receiver ID indicating the receiver 102 or the receiver 202 that calculated the comparison target value. The comparison target value acquisition unit 323 associates the comparison target value indicated by the input comparison target value notification message with the receiver ID included in the same comparison target value notification message.
The comparison target value acquisition unit 323 stores the comparison target value associated with the receiver ID as described above in the comparison target value information stored in the comparison target value information storage unit 343 of the storage unit 304.

The transmission permission / inhibition determination unit 324 determines whether or not transmission should be permitted for the transmitter.
The transmission permission / inhibition determination unit 324 determines whether or not transmission should be permitted in order from the transmitter with the fewest transmission opportunities.
Further, the transmission permission / inhibition determination unit 324 determines, for each transmitter to be determined, the remaining number of interference waves that can be removed, which is the remaining number of interference waves that can be removed by the receiver when the transmitter to be determined performs transmission. , Based on the interference wave number and interference relation information. Then, the transmission permission / inhibition determination unit 324 determines the number of residual interference waves that can be removed for each receiver (reception-determined receiver) that is the destination of the transmitter that has already been determined to permit transmission, and the transmitter that is the determination target. It is determined that the transmission should be permitted when the condition that both of the remaining number of interference waves that can be removed by the receiver are equal to or greater than the comparison target value is satisfied.
On the other hand, the transmission permission / inhibition determination unit 324 determines that transmission should not be permitted when the above condition is not satisfied. That is, the transmission permission / inhibition determination unit 324 compares at least one of the number of remaining interference waves that can be removed by the reception-determined receiver and the number of remaining interference waves that can be removed by the receiver that is the destination of the determination target transmitter. If it is less than the target value, it is determined that transmission should not be permitted for the transmitter to be determined.
Note that transmission history information used for derivation of transmission opportunities is stored in the transmission history information storage unit 341 of the storage unit 304.

The transmission history information update unit 325 updates the transmission history information stored in the transmission history information storage unit 341 in accordance with the result of the transmission availability determination by the transmission availability determination unit 324.
The transmitter whose transmission is permitted by the transmission allocation unit 302 performs transmission according to a control message transmitted by a transmitter control unit 303 described later. That is, the fact that the transmission history information update unit 325 updates the transmission history information in accordance with the result of the transmission permission / inhibition determination by the transmission permission / inhibition determination unit 324 means that the transmitter permitted to transmit has transmitted. This corresponds to updating the transmission history information.

The transmitter control unit 303 controls the transmission operation of the transmitter according to the determination result of the transmission permission determination unit 324.
Specifically, when it is determined by the transmission permission / inhibition determination unit 324 that transmission is to be permitted for a certain determination target transmitter, the transmitter control unit 303 indicates a control message (transmission permission message) indicating transmission permission. Is transmitted from the transmission unit 305 to the transmitter to be determined. In the transmission permission message, for example, a time allocated for transmission (transmission time) and a slot allocated for transmission (allocation slot) are shown. Note that the transmission permission / inhibition determination unit 324 may determine the transmission time and the allocation slot.
The transmitter to be determined performs transmission according to the transmission time and the assigned slot specified by the received transmission permission message.
On the other hand, if it is determined by the transmission permission determination unit 324 that transmission should not be permitted for the transmitter to be determined (transmission standby), the transmission permission message is not transmitted. As a result, the transmitter to be determined does not receive the transmission permission message, and therefore maintains the state waiting for transmission.
As described above, the transmitter control unit 303 causes the transmitter to perform transmission by transmitting the transmission permission message, and causes the transmitter to enter a standby state without performing transmission by not transmitting the transmission permission message. Can be controlled.

The storage unit 304 stores information used by the transmission allocation unit 302. The storage unit 304 shown in the figure includes a transmission history information storage unit 341, an interference situation information storage unit 342, and a comparison target value information storage unit 343.
The transmission history information storage unit 341 stores transmission history information. The transmission history information includes a transmission time and the number of allocated slots in transmissions performed so far by each of the transmitters (transmitters 101 and 201).
The transmission history information updating unit 325 acquires the transmission time and the number of allocated slots based on the transmission time and the allocated slots determined for the transmitter that the transmission permission / inhibition determining unit 324 determines to allow transmission. Then, the acquired transmission time and the number of allocated slots are newly included in the transmission history information in association with the transmitter that is determined to be permitted to transmit by the transmission permission determination unit 324. In this way, the transmission history information stored in the transmission history information storage unit 341 is updated.

  The interference situation information storage unit 342 stores interference situation information. The interference state information is information formed including predetermined information indicating the state of radio wave interference in the communication system. For example, the interference state information includes interference wave number information indicating the interference wave number acquired by the interference wave number acquisition unit 321.

  FIG. 6 shows an example of the content of the interference wave number information. The interference wave number information in the figure has a structure in which the interference wave number is stored in association with the receiver ID corresponding to each receiver (receiver 102, 202). The interference wave number is based on the interference wave number notification message received by the control station 300, and indicates the interference wave number received from another system detected by the receiver indicated by the receiver ID stored in the interference wave number information. .

Further, the interference status information stored in the interference status information storage unit 342 includes maximum removable interference wave number information indicating the upper limit (removable maximum interference wave number) of the removable interference waves for each of the receivers 102 and 202.
FIG. 7 shows an example of the content of the maximum interference wave number information that can be removed. The removable maximum interference wave number information in the figure has a structure in which the maximum removable interference wave number is stored in association with the receiver ID corresponding to each of the receivers 102 and 202.
When the blind type adaptive array antenna technology is adopted as described above, the maximum number of interference waves that can be removed by one receiver is determined according to the number of antennas that the receiver uses for reception. Specifically, the maximum number of interference waves that can be removed is n−1 when the number of antennas is represented by n. That is, the maximum number of interference waves that can be removed is equal to the number obtained by subtracting 1 from the number of antennas that the receiver uses for reception.
The maximum removable interference wave number information may be stored in advance in the interference situation information storage unit 342 when the maximum removable interference wave number for each of the receivers 102 and 202 is known, for example.
Alternatively, each of the receivers 102 and 202 notifies the control station 300 of the maximum number of interference waves that can be removed at a predetermined timing. In addition, the control station 300 may store the maximum removable interference wave number information in the interference state information storage unit 342 using the notified maximum removable interference wave number.

Further, the comparison target value information storage unit 343 stores the comparison target value acquired by the comparison target value acquisition unit 323 as comparison target value information.
FIG. 8 shows an example of the contents of the comparison target value information stored in the comparison target value information storage unit 343. The comparison target value information in the figure has a structure in which the comparison target value is stored in association with the receiver ID corresponding to each receiver (receiver 102, 202). The comparison target value is based on the comparison target value notification message received by the control station 300, and indicates the comparison target value calculated in the receiver indicated by the receiver ID stored in the comparison target value information.

[Example of processing procedure]
The flowchart of FIG. 9 shows an example of a processing procedure executed by the receivers 102 and 202 in the communication system of the present embodiment regarding detection and notification of the number of interference waves. Here, the receiver 102 in the base station 100 will be described as an example.
In the receiver 102, the interference wave number detection unit 1222 waits until the detection timing is reached (step S101—NO). The detection timing may be a fixed time interval based on, for example, a frame or a slot (time slot).
When the detection timing is reached (step S101—YES), the interference wave number detection unit 1222 detects the interference wave number currently received from another system. (Step S102).
The notification unit 123 generates an interference wave number notification message indicating the interference wave number detected in step S102, and performs control so that the generated interference wave number notification message is transmitted to the control station 300 (step S103).

  In the receiver 202 of the terminal device 200, the process shown in FIG. 10 is performed by the interference wave number detection unit 2222 and the notification unit 2123. Thereby, the terminal device 200 detects the interference wave number, and the detected interference wave number is transmitted from the terminal device 200 to the control station 300.

Next, a processing procedure example executed by the receivers 102 and 202 in relation to the calculation of the comparison target value and the notification will be described with reference to the flowchart of FIG. Here, the receiver 102 in the base station 100 will be described as an example.
In the receiver 102, the comparison target value calculation unit 1223 executes a process for acquiring a comparison target value calculation parameter (step S201).
Next, the comparison target value calculation unit 1223 calculates a comparison target value using the comparison target value calculation parameter acquired in step S201 (step S202).
The notification unit 123 generates a comparison target value notification message indicating the comparison target value calculated in step S202, and executes control so that the generated interference wave number notification message is transmitted to the control station 300 (step S203).

Here, a specific example of the comparison target value calculation parameter acquisition process (step S201) and the comparison target value calculation process (step S202) in the present embodiment will be described.
The comparison target value calculation parameter in the present embodiment is a reception error rate.
The transmitter performs transmission using the assigned slot. However, for example, due to unexpected interference, the transmitted slot may not be normally received by the receiver, resulting in a reception error. . The reception error rate indicates the frequency of such reception errors. The reception error rate is one of parameters that change depending on the state of interference waves received by the receiver.

The comparison target value calculation unit 1223 in the present embodiment acquires the reception error rate as the comparison target value calculation parameter as follows.
First, the comparison target value calculation unit 1223 detects the number of slots in which a reception error has occurred (the number of reception error slots) every t seconds as a predetermined unit period. Here, assuming that the slot length is s seconds, the slot number NST allocated in the unit period of t seconds is represented by t / s. In addition, assuming that the number of reception error slots is NRI, the reception error rate RI is expressed by the following Equation 1.
RI = NRI / NST = NRI × s / t (Formula 1)
That is, the comparison target value calculating unit 1223 detects the reception error slot number NRI in a unit period of t seconds, and then calculates the reception error rate RI using the above equation 1. In this way, the comparison target value calculation unit 1223 acquires the reception error rate RI for each unit period of t seconds as step S201.

  Then, the comparison target value calculation unit 1223 uses the comparison target value calculation parameter as the reception error rate RI acquired by the comparison target value calculation unit 1223 as described above to calculate the comparison target value M by the following equation 2. calculate.

In Equation 2, M _k represents a comparison target value corresponding to the timing of the kth assigned slot. RI _TH1 and RI _TH2 are thresholds for the reception error rate RI, respectively, and have a relationship of RI _TH1 > RI _TH2 .
The initial value of the comparison target value M may be set to a predetermined value in consideration of various conditions. In Expression 2, a and b are constants each of which is a positive integer, and are step amounts for the comparison target value.

According to Equation 2, the comparison target value calculation unit 1223 adds a constant a to the comparison target value M _k corresponding to the k-th slot when (RI> RI _TH1 ) holds for the reception error rate RI. Thus, the comparison target value M _{k + 1} corresponding to the next k + 1 th slot is calculated.
That is, when (RI> RI _TH1 ) is satisfied, the reception error rate RI is considerably high, and the interference received by the receiver side is high. Therefore, in this case, a margin is given to the comparison target value by setting the comparison target value higher than the previous value. As a result, the conditions under which transmission is permitted for the transmitter become severe. As a result, the number of transmitters that perform transmission is reduced, the generation of interference waves is suppressed, and there is a high possibility that the remaining number of interference waves that can be removed by the receiver is increased, thereby maintaining the stability of communication. be able to.

In addition, when the reception error rate RI is satisfied (RI _TH2 <RI ≦ RI _TH1 ), the comparison target value calculation unit 1223 sets the comparison target value M _k corresponding to the kth slot as it is to the next k + 1th. Is calculated as a comparison target value M _{k + 1} corresponding to the slot. That is, in this case, the constant added to or subtracted from the comparison target value _Mk is “0”.
When (RI _TH2 <RI ≦ RI _TH1 ) holds, the reception error rate RI is standard. Therefore, in this case, the same value as the previous value is maintained for the comparison target value.

In addition, when the reception error rate RI satisfies (RI ≦ RI _TH2 ), the comparison target value calculation unit 1223 subtracts the constant b from the comparison target value M _k corresponding to the kth slot, thereby The comparison target value M _{k + 1} corresponding to the (k + 1) th slot is calculated.
When (RI ≦ RI _TH2 ) is satisfied, the reception error rate RI is considerably low, for example, there is little interference received by the receiver. Therefore, in this case, by setting the comparison target value lower than the previous value, the conditions for permitting transmission for the transmitter are relaxed, and transmission is performed by many transmitters. Thereby, the frequency use efficiency by user multiplexing can be improved.

In step S203, the notification unit 123 generates a comparison target value notification message indicating the comparison target value M _{k + 1} calculated as described above as the comparison target value M, and transmits the generated comparison target value notification message.

In the present embodiment, also in the receiver 202 of the terminal device 200, the comparison target value calculation unit 2223 acquires the reception error rate RI as a comparison target value calculation parameter (step S201), and the comparison target value calculation unit 2223. However, the comparison target value M _{k + 1} is calculated using the reception error rate RI (step S202). Then, the notification unit 2123 generates a comparison target value notification message indicating the calculated comparison target value M _{k + 1} as the comparison target value M, and transmits the generated comparison target value notification message (step S203).

Next, an example of a processing procedure executed by the control station 300 in the communication system of the present embodiment will be described with reference to the flowchart of FIG.
The interference relationship information acquisition unit 322 in the control station 300 acquires interference information indicating the interference relationship in the own communication system (step S301). Therefore, the interference relationship information acquisition unit 322, for example, sequentially transmits pilot signals from the transmitters 101 and 201 as described above, and collects pilot signal reception responses returned from the receivers every time the pilot signals are transmitted. To do. Then, the interference relation information acquisition unit 322 identifies the interference relation from the collection result of the pilot signal reception response, and is included in the interference situation information stored in the interference situation information storage unit 342 based on the interference relation information indicating the identified interference relation. Updated interference relation information (illustrated in FIG. 5).
Moreover, when starting the process of step S301, the interference related information acquisition part 322 starts time measurement from the state which reset the interference condition update timer.

  Next, the interference wave number acquisition unit 321 in the control station 300 acquires the interference wave number detected by each of the receiver 102 of the base station 100 and the receiver 202 of the terminal device 200 (step S302). The interference wave numbers detected by the receivers 102 and 202 are transmitted to the control station 300 as the interference wave number notification message as described above. The interference wave number acquisition unit 321 uses the interference wave number information in which the interference wave number included in the received interference wave number notification message is associated with the receiver ID to store the interference state information stored in the interference state information storage unit 342 (illustrated in FIG. 6). ). In this way, the control station 300 acquires the interference wave number.

  Next, the comparison target value acquisition unit 323 in the control station 300 acquires the comparison target value calculated by each of the receiver 102 of the base station 100 and the receiver 202 of the terminal device 200 (step S303). The comparison target values calculated by the receivers 102 and 202 are transmitted to the control station 300 as an interference wave number notification message as described above. The comparison target value acquisition unit 323 compares the comparison target value information stored in the comparison target value information storage unit 343 with the comparison target value information in which the comparison target value included in the received comparison target value notification message is associated with the receiver ID. Information (illustrated in FIG. 8) is updated. In this way, the control station 300 acquires the comparison target value.

Next, the control station 300 performs transmission permission / inhibition determination, transmitter control, and transmission history information update processing (step S304).
The transmission permission / inhibition determination unit 324 performs the transmission permission / inhibition determination. The transmission permission / inhibition determination is a process in which the transmission permission / inhibition determination unit 324 sequentially determines whether transmission should be permitted for each of the transmitters 101 and 201.
The determination as to whether or not transmission should be permitted is made based on the interference status of the receivers 102 and 202 estimated when the transmitter to be determined performs transmission. The interference status of the receivers 102 and 202 is estimated using the interference relationship information updated corresponding to step S301 and the interference wave number information updated corresponding to step S302.
Further, when determining whether or not transmission should be permitted, a comparison is made between the comparison target value updated corresponding to step S303 and the number of remaining interference waves that can be removed by the receiver.
Further, the order of transmitters to be determined when determining whether or not to permit transmission is determined based on the transmission history information according to the order of few transmission opportunities so far. That is, the determination as to whether or not to permit transmission for each transmitter is performed in the order of giving priority to transmitters with few transmission opportunities.

In the same step S304, the transmitter control unit 303 performs control such that the transmitter determined by the transmission permission determination unit 324 to permit transmission performs transmission as transmitter control. Specifically, as described above, the transmitter control unit 303 transmits a transmission permission message indicating the transmission time and allocation slot determined by the transmission permission / inhibition determination unit 324 to the transmitter to be determined.
Further, as transmitter control, the transmitter control unit 303 permits transmission when it is determined by the transmission permission determination unit 324 that transmission should not be permitted (waiting for transmission) for the determination target transmitter. Do not send messages. Thereby, it can be set as the state which waited for transmission about the transmitter of determination object.

In the same step S304, the transmission history information update unit 325 updates the transmission history information according to the determination result of the transmission permission / inhibition determination unit 324.
In other words, as described above, the transmission history information update unit 325, when the transmission permission determination unit 324 determines that transmission should be permitted for the determination target transmitter, the transmission history of the determination target transmitter is transmitted to the transmission history. Update to include new information. As described above, the transmission history corresponding to one transmission from the transmitter includes the transmission time determined by the transmission permission determination unit 324 and the number of allocation slots (number of allocation slots) included in the transmission permission message. .

The control station 300 determines whether or not the time (timer time) counted by the interference status update timer that has started timing in accordance with step S301 has expired (step S305). The determination in step S305 may be performed by the interference relationship information acquisition unit 322, for example.
If the timer time has not expired (step S305-NO), the processing of steps S302 to S304 is performed again. That is, the acquisition of the interference wave number in step S302, the acquisition of the comparison target value in step S303, the transmission propriety determination in step S304, the transmitter control, and the update of the transmission history information are performed in a loop process until the timer time expires. Is repeatedly executed.
Then, when the timer time expires (step S305-YES), the process is returned to step S301. As a result, the transmission permission / inhibition determination is performed after updating the interference relation information.
As described above, the interference relationship in the communication system changes with the passage of time according to the position of the terminal device 200 that is a mobile station, the radio wave condition, and the like. Therefore, the transmission availability determination unit 324 appropriately determines the transmission availability according to the current state of the communication system by performing the transmission availability determination after updating the interference-related information at regular time intervals (timer time). It can be performed.

The flowchart of FIG. 12 shows an example of a processing procedure executed by the control station 300 for the determination of whether transmission is possible, the transmitter control, and the transmission history information update as step S304 of FIG.
First, the transmission permission / inhibition determination unit 324 substitutes an initial value “1” into a variable j indicating the number of times a transmitter to be determined is selected (step S401).

Next, the transmission permission / inhibition determining unit 324 selects the transmitter i as the jth determination target from the transmitters 101 and 201 (step S402). The process of step S402 can be expressed as a function according to the following Expression 3.
S (j) = i (Expression 3)
Expression 3 indicates that the j-th determination target is the transmitter i. Note that i represents a number assigned to the transmitter. As an example, a transmitter ID can be used for the number i.

In the present embodiment, Equation 3 is a function that sorts the transmitters in ascending order of index values indicating transmission opportunities. Specifically, the following can be given as index values as transmission opportunities.
The index value indicating the transmission opportunity can be an integrated value for the transmission time when the transmitter has performed transmission so far. The transmission permission / inhibition determination unit 324 can acquire the transmission time when the transmitter performs transmission from the transmission history information stored in the transmission history information storage unit 341.
Further, the index value indicating the transmission opportunity can be a moving average value of the transmission time in the past up to a certain period.

The index value indicating the transmission opportunity can be an integrated value of the amount of data (transmission data amount) transmitted when the transmitter performs transmission. The transmission permission / inhibition determination unit 324 can determine the transmission data amount in one transmission based on, for example, the transmission time and the allocation slot in the transmission history information. That is, the amount of transmission data in one transmission is obtained by multiplying the amount of data that can be transmitted by the allocation slot and the transmission time.
The index value indicating the transmission opportunity can be a moving average value of the amount of transmission data in the past up to a certain period.

Next, when it is assumed that the transmitter i has performed transmission, the transmission permission / inhibition determination unit 324 calculates the removable interference wave remaining number N ^a _x of the receiver x to which the transmitter i causes interference (step S403). .
As a specific example, the receiver x when the transmitter i is the transmitter 201-1 (transmitter ID = T01) under the interference relationship illustrated in FIG. Receiving receiver 102 (receiver ID = R00), receiver 202-1 (receiver ID = R01), and receiver 202-2 (receiver ID = R02).
Further, the removable interference wave remaining number N ^a _x is the remaining number of interference waves that can be removed by the receiver x.

Then, in step S403, the transmission permission / inhibition determination unit 324 calculates the removable interference wave remaining number N ^a _x by the following expression 4.
N ^a _x = N ^a _x −1 (Formula 4)
That is, when the transmitter i transmits, the radio wave of the transmitter i reaches the receiver x and increases the number of interference waves by one. Then, the receiver x removes the interference wave from the transmitter i. Therefore, the remaining interference wave remaining number N ^a _x of the receiver x is reduced by one according to Equation 4.

Here, in the first step S403 in the process in which the loop process of steps S402 to S412 is repeated, the transmission permission / inhibition determining unit 324 uses the initial value of the remaining number of removable interference waves N ^a _x to remove the remaining interference wave. The number N ^a _x is calculated.
The initial value of the removable interference wave remaining number N ^a _x is obtained by subtracting the interference wave number detected by the receiver x from the maximum removable wave number of the receiver x. That is, the transmission permission / inhibition determining unit 324 can obtain the initial value of the removable interference wave remaining number N ^a _x using the maximum removable wave number information and the interference wave number information stored in the interference state information storage unit 342. .

In addition, when it is assumed that the transmitter i has performed transmission, the transmission permission / inhibition determination unit 324 calculates the number of remaining interference waves N ^a _y of the receiver y that is the destination of the transmitter i (step S404).
Here, the receiver y that is the destination of the transmitter i is one of the receivers x for which the remaining interference wave remaining number N ^a _x has been calculated in step S403.
The signal transmitted from the transmitter i for the receiver y is a desired signal and does not need to be removed as an interference wave. However, in step S403, the remaining interference wave remaining number is also subtracted for the receiver y. Therefore, in step S404, the transmission permission / inhibition determining unit 324 calculates the remaining interference wave removal number N ^a _y of the receiver y by the following equation 5.
N ^a _y = N ^a _x +1 (Formula 5)
That is, according to Expression 5, the removable interference wave remaining number N ^a _y is obtained by returning the remaining interference wave remaining number N ^a x subtracted in step S403 to the value before the subtraction.

Next, the transmission permission / inhibition determination unit 324 sets the remaining number of removable interference waves N ^a calculated for each of the receivers that have already been set as reception-determining devices and the transmitter i to be determined this time as the destination. It is determined whether or not all of the remaining interference wave removal numbers N ^a _y of the receiver y are equal to or greater than the comparison target value M updated corresponding to step S303 in FIG. 11 (step S405).
Here, the reception confirmation device is a receiver whose destination is a transmitter that is determined to permit transmission in the process of looping the processing of steps S402 to S412.

For example, in step S405, instead of the receiver removable interference remaining number N ^a of the receiver determined machine, transmission request all possible receivers removal of a receiver made to transmitter interference wave remaining number N ^a Can also be used for determination.
However, there is no need to control the transmitter in order to maintain normal reception for a receiver that is determined to be unable to transmit with respect to the transmission request destination transmitter (that is, a receiver that does not perform reception). , there is no particular problem even without spare receiver removable interference remaining number N ^a.
Therefore, as in the present embodiment, by using the receiver removable interference remaining number N ^a is limited to the receiver confirm machine, removable interference remaining number N ^a of not receive confirmation Receiver transmission It will no longer affect the result of machine availability. Thereby, it becomes possible to improve the determination accuracy in step S405.

When it is determined that the comparison target value M is equal to or greater than the comparison target value M (step S405—YES), there is a margin in the number of interference waves that can be removed by the receiver. It can be estimated that the machine is in a state where it can receive the desired signal properly by removing the interference wave.
Therefore, in this case, the transmission permission / inhibition determination unit 324 determines that the transmission of the transmitter i should be permitted (step S406).
In addition, in the same step S406, the transmission permission / inhibition determination unit 324 sets the receiver y, which is the destination of the transmitter i determined to be permitted to transmit, as the reception confirmation device.

In response to the determination in step S406, the transmitter control unit 303 transmits a transmission permission message to the transmitter i (step S407). As described above, the transmission permission message includes information specifying the transmission time and the allocation slot determined by the transmission permission determination unit 324 corresponding to the transmitter that is determined to be permitted to transmit.
Further, the transmission history information update unit 325 updates the transmission history information according to the determination made in step S406 (step S408). Specifically, the transmission history information updating unit 325 determines the transmission time and the number of allocation slots (number of allocation slots) determined by the transmission permission / inhibition determination unit 324 corresponding to the transmitter permitted to transmit as the transmitter i. The associated transmission history information is newly stored in the transmission history information storage unit 341. As a result, the transmission result to be performed by the transmitter i in response to the transmission permission message transmitted in step S407 is reflected in the transmission history information.

On the other hand, at least any one of the removable interference remaining number N ^a _y receiver y and calculated removable interference wave remaining number N ^a For each received confirmation machine in less than comparison value M If there is (step S405—NO), it is estimated that there is a high possibility that there is a receiver that receives the number of interference waves exceeding the maximum number of interference waves that can be removed. That is, it is estimated that there is a receiver that cannot properly receive the desired signal in the communication system.
Therefore, the transmission permission / inhibition determination unit 324 in this case determines that the transmission of the transmitter i should be waited (step S409).
If it is determined in step S409 that the transmission of the transmitter i should be waited, the processes in steps S407 and S408 are skipped. As a result, the transmitter i maintains a state of waiting for transmission because it does not receive the transmission permission message. Also, transmission history information for the transmitter i is not updated.
If it is determined in step S409 that transmission from the transmitter i should be waited, transmission by the transmitter i is not performed. Here, the remaining removable interference wave number N ^a _x for each receiver x calculated in the previous step S403 is a value when it is assumed that the transmitter i performs transmission. For this reason, if it is determined in step S409 that transmission from the transmitter i should be waited and the transmitter i does not perform transmission, the remaining removable interference wave number N ^a _x is calculated in step S403. It is necessary to set it back to the value before being used.
Assuming that that executes the loop processing of the subsequent steps S402~S412 without returning the value of removable interference remaining number N ^a _x, errors in removable interference remaining number N ^a _x calculated in step S403 As a result, an error also occurs with respect to the remaining interference wave remaining number N ^a _y of the receiver y. As a result, an error also occurs in the determination in step S405.
Therefore, when it is determined in step S409 that the transmission of the transmitter i should be waited, the transmission availability determination unit 324 returns the remaining interference wave remaining number N ^a _x to the value before the calculation in step S403 ( Step S410). For this purpose, the transmission permission / inhibition determining unit 324 may perform, for example, decrementing (N ^a _x = N ^a _x −1) on the current removable interference wave remaining number N ^a x.

When the process of step S408 or the process of step S410 ends, the transmission permission / inhibition determination unit 324 increments the variable j (step S411).
Next, the transmission permission / inhibition determination unit 324 determines whether or not the variable j incremented in step S411 is larger than the total number N of transmitters (step S412). Specifically, the total number N of transmitters is “4” under the configuration of the communication system of this embodiment shown in FIG.

  When it is determined that the variable j is less than or equal to the total number N of transmitters (step S412-NO), there are still transmitters that are not yet determined as transmission targets. Therefore, the transmission permission / inhibition determination unit 324 in this case returns the process to step S402. As a result, it is determined whether or not transmission is possible, with a transmitter having the smallest index value indicating a transmission opportunity among the transmitters that are not determined as transmission possible.

  When the determination of whether transmission is possible for all transmitters is completed, it is determined that the variable j is larger than the total number N of transmitters (step S412-YES), and the processing as step S304 in FIG.

As described above, the control station 300 according to the present embodiment determines whether or not transmission is possible for each transmitter, determines that the transmitter that is determined to permit transmission is to perform transmission, and waits for transmission. The assigned transmitter is assigned transmission so as to wait for transmission.
Here, the transmission permission / inhibition determination uses the interference relationship between the transmitter and the receiver in the own communication system and the number of interference waves detected by the receiver. As a result, in the communication system of the present embodiment, the user can utilize the surplus of the removable interference wave number for transmission of the transmitter while preventing the interference wave number received by each receiver from exceeding the maximum removable wave number. Multiplexing is possible.
Further, in the present embodiment, the comparison target value used for comparison with the maximum removable interference wave number in step S405 in FIG. 12 is obtained using the reception error rate. The reception error rate reflects the interference situation received by the receiver, and the interference situation received by the receiver changes with time. That is, the comparison target value in the present embodiment is dynamically obtained according to the time variation of the interference situation received by the receiver. As a result, in the present embodiment, it is possible to perform appropriate transmission assignment so as to follow the time variation of the interference situation received by the receiver as compared with, for example, a case where the comparison target value is a fixed value. .
In this embodiment, when performing transmission assignment as described above, transmission resources are preferentially assigned from transmitters with few transmission opportunities based on transmission history information. Can be equalized. Thus, in this embodiment, it becomes possible to improve the frequency utilization efficiency in a communication system.

Second Embodiment
In each of the second and subsequent embodiments described below, the comparison target value calculation parameters acquired by the receiver 102 of the base station 100 and the receiver 202 of the terminal device 200 are different from those of the first embodiment. Accordingly, the processing in which the receivers 102 and 202 calculate the comparison target value using the comparison target value calculation parameter is also different from the first embodiment.

First, acquisition of a comparison target value calculation parameter and calculation of a comparison target value in the second embodiment will be described. In the description, first, the case of the receiver 102 of the base station 100 in the present embodiment will be described as an example.
The comparison target value calculation unit 1223 of the receiver 102 acquires the maximum value NI _{k of the} number of interference waves from other systems in the kth allocation slot. For this purpose, the comparison target value calculation unit 1223 may acquire the maximum value of the interference wave numbers detected by the interference wave number detection unit 1222 during the period corresponding to the kth allocation slot as the maximum value NI _k .
In addition, the comparison target value calculation unit 1223 acquires the maximum value among the maximum values NI _{k in} the past t seconds (an example of a certain period) as the intra-period maximum value NI _t . Also, the comparison target value calculation unit 1223 obtains the interference wave number (current interference wave number NI _G ) from another system that it currently receives from the interference wave number detection unit 1222.
In the present embodiment, the in-period maximum value NI _t acquired as described above is the comparison target value calculation parameter.

Then, the comparison target value calculation unit 1223 in the same receiver 102 uses the maximum value NI _t within the period and the current interference wave number NI _G acquired as the comparison target value calculation parameters as described above, and the following equation 6 Thus, a comparison target value M _{k + 1} used to determine whether transmission is possible in correspondence with the timing of the next (k + 1) th allocation slot is calculated.
M _{k + 1} = NI _t −NI _G (Expression 6)
That is, the comparison target value calculation unit 1223 according to the present embodiment calculates the comparison target value M _{k + 1} by subtracting the current interference wave number NI _G from the maximum value NI _t within the period.

The processing of FIG. 9 in the present embodiment is as follows. In the receiver 102, the comparison target value calculating unit 1223, a comparison value calculation parameter, and acquires the time the maximum value NI _t and the current interference wave number NI _G (step S201).
Further, the comparison target value calculation unit 1223 uses the maximum value NI _t and the current interference wave number NI _G acquired as the comparison target value calculation parameters in step S201, and the comparison target value M _{k + 1 according} to the above equation 6. Is calculated (step S202).
And the notification part 123 transmits the comparison object value notification message which shows the comparison object value _{Mk + 1} calculated by step S202 to the control station 300 (step S203).

Also, the same processing as described above is performed in the receiver 202 of the terminal device 200 in the present embodiment. That is, the comparison target value calculation unit 2223 acquires the in-period maximum value NI _t and the current interference wave number NI _G as the comparison target value calculation parameters (step S201).
Further, the comparison target value calculation unit 2223 uses the maximum value NI _t and the current interference wave number NI _G acquired as the comparison target value calculation parameters in step S201, and the comparison target value M _{k + 1 according} to the above equation 6. Is calculated (step S202).
Then, the notification unit 2123 transmits a comparison target value notification message indicating the comparison target value M _{k + 1} calculated in step S202 to the control station 300 via the base station 100 (step S203).

The intra-period maximum value NI _t that is one of the comparison target value calculation parameters in the present embodiment is the maximum value of the number of interference waves in t seconds. That is, the maximum value NI _t within the period varies according to the temporal change of the interference situation in the receiver. In other words, the maximum value NI _t within the period is a parameter that is dynamically determined according to the temporal variation of the interference situation experienced by the receiver.
Similarly, the current interference wave number NI _G is one of the comparison object value calculated parameters in the present embodiment is also a parameter which is dynamically determined in accordance with the temporal change of the interference situation at the receiver.

Then, the transmission propriety determination unit 324 of the control station 300 in the present embodiment uses the comparison target value M _{k + 1} indicated in the comparison target value notification message received from the base station 100 or the terminal device 200 as the comparison target value M, The process in step S405 in FIG. 12 is executed.
Also in the case of the present embodiment, if it is determined in step S405 that all of the removable interference remaining numbers N ^a _y of the reception determinator and the receiver y are greater than or equal to the comparison target value M, the transmitter i Even if transmission is performed, it can be estimated that each receiver in the communication system is in a state where it can properly receive the desired signal by removing the interference wave.
On the other hand, in step S405, at least any one of the comparison object value M of the removable interference remaining number N ^a _y receiver y and calculated removable interference wave remaining number N ^a For each receiver deterministic machine If it is less than that, it is estimated that there is a high possibility that there is a receiver that receives the number of interference waves exceeding the maximum number of interference waves that can be removed.
Therefore, by using the comparison target value obtained as in the present embodiment, similarly to the first embodiment, the transmission allocation is appropriately performed by dynamically following the temporal variation of the interference situation. Is possible.

<Third Embodiment>
Subsequently, the third embodiment will be described. The receiver 102 of the base station 100 in this embodiment performs acquisition of a comparison target value calculation parameter and calculation of a comparison target value as follows.

The comparison target value calculation unit 1223 of the receiver 102 acquires the maximum value NI _{k of the} number of interference waves from other systems in the kth allocation slot. The comparison target value calculation unit 1223 acquires a plurality of maximum values NI _k for a predetermined past t seconds.
The plurality of maximum values NI _k acquired in t seconds as described above have a certain distribution with respect to the appearance frequency, for example. In this case, for example, there is a possibility that the appearance frequency of the maximum value among the plurality of maximum values NI _k in t seconds is very small. In this case, since the maximum value among the maximum values NI _k appears instantaneously, the influence on communication can be almost ignored. According to such a concept, the largest influence on communication is the maximum value NI _k having the largest value in the range where the appearance frequency is a certain level or more.
Therefore, the comparison target value calculation unit 1223 excludes a plurality of maximum values NI _k for t seconds whose appearance frequency is equal to or lower than a predetermined x% (corresponding to the collision rate allowable amount). Next, the comparison target value calculation unit 1223 acquires the maximum value (frequency-corresponding maximum value NI _{t (x%)} ) in the maximum value NI _k remaining without being excluded as a comparison target value calculation parameter. In this way, in the present embodiment, the maximum value NI _k having the largest value in the range where the appearance frequency is constant or higher in t seconds is acquired as one of the comparison target value calculation parameters.
Further, the comparison target value calculation unit 1223 also acquires the current interference wave number NI _G as another comparison target value calculation parameter.

Then, the comparison target value calculation unit 1223 in the same receiver 102 uses the frequency-corresponding maximum value NI _{t (x%)} acquired as the comparison target value calculation parameter and the current interference wave number NI _G as described above, A comparison target value M _{k + 1} used to determine whether or not transmission is possible in accordance with the timing of the next (k + 1) th allocation slot is calculated by the following Expression 7.
M _{k + 1} = NI _{t (x%)} − NI _G (Expression 7)
That is, the comparison target value calculation unit 1223 according to the present embodiment calculates the comparison target value M _{k + 1} by subtracting the current interference wave number NI _G from the frequency-corresponding maximum value NI _{t (x%)} .

The processing of FIG. 9 in this embodiment is as follows. In the receiver 102, the comparison target value calculation unit 1223 obtains the frequency-corresponding maximum value NI _{t (x%)} and the current interference wave number NI _G as the comparison target value calculation parameters (step S201).
The comparison object value calculating unit 1223 uses the acquired as comparison object value calculated parameters a frequency corresponding maximum value NI t and _(x%) and the current interference wave number NI _G in step S201, comparing the equation 7 above A target value M _{k + 1} is calculated (step S202).
And the notification part 123 transmits the comparison object value notification message which shows the comparison object value _{Mk + 1} calculated by step S202 to the control station 300 (step S203).

In the receiver 202 of the terminal device 200 in the present embodiment, the same processing as described above is performed. That is, the comparison target value calculation unit 2223 obtains the frequency-corresponding maximum value NI _{t (x%)} and the current interference wave number NI _G as the comparison target value calculation parameters (step S201).
The comparison object value calculating unit 2223 uses the acquired as comparison object value calculated parameters a frequency corresponding maximum value NI t and _(x%) and the current interference wave number NI _G in step S201, comparing the equation 7 above A target value M _{k + 1} is calculated (step S202).
Then, the notification unit 2123 transmits a comparison target value notification message indicating the comparison target value M _{k + 1} calculated in step S202 to the control station 300 via the base station 100 (step S203).

The frequency-corresponding maximum value NI _{t (x%)} , which is one of the comparison target value calculation parameters in the present embodiment, also varies according to the temporal change in the interference state for t seconds. That is, the frequency-corresponding maximum value NI _{t (x%)} is also a comparison target value calculation parameter that is dynamically determined according to the temporal variation of the interference state. Therefore, also in the present embodiment, it is possible to appropriately perform transmission allocation by dynamically following the temporal variation of the interference situation.

<Fourth embodiment>
Subsequently, a fourth embodiment will be described. In the present embodiment, the following three are used as comparison target value calculation parameters. First, one is a current interference wave number NI _G. The other is either the maximum value NI _t within the period acquired in the previous second embodiment or the frequency-corresponding maximum value NI _{t (x%)} acquired in the previous third embodiment. It is. Yet another comparison target value calculation parameter is the number of interference sources having a collision avoidance function in other systems (the number of collision avoidance interference sources).
Here, the interference source is a transmitter that interferes with a receiver of the own communication system. Therefore, an interference source having a collision avoidance function is a transmitter that performs transmission according to a communication method having a collision avoidance function among transmitters that interfere with a receiver of the local communication system in another system. .

Based on the state of the interference wave detected in the period of t seconds, the comparison target value calculation unit 1223 does not transmit when the receiver 102 is receiving data, but does not transmit data when the receiver 102 is not receiving data. Is obtained. The number of interference sources determined in this way is acquired as the collision avoidance interference source number NC _t .
Specifically, the comparison target value calculation unit 1223 detects the arrival direction and energy for each interference wave from another system in a period during which data is received for t seconds, and in a period during which no data is received during the same t seconds. The direction of arrival and energy for each interference wave from another system are detected.
By performing detection in this way, the interference source (transmitter) of the other system that arrives during the period of data reception and the other that arrives during the period when data is not received, depending on the arrival direction and energy of each interference wave Identify sources of system interference.
In addition, the comparison target value calculation unit 1223 identifies an interference source that has never arrived during the period of data reception but has arrived during a period of no data reception. The comparison target value calculation unit 1223 acquires the number of interference sources identified in this way as the collision avoidance interference source number NC _t .

When the comparison target value calculation unit 1223 uses the maximum value NI _t within the period and the collision avoidance interference source number NC _t , the comparison target value calculation unit 1223 corresponds to the timing of the next (k + 1) th allocation slot according to the following equation 8. A comparison target value M _{k + 1} used to determine whether transmission is possible is calculated.
M _{k + 1} = NI _t − (NI _G + NC _t ) (Equation 8)
That is, the comparison target value calculation unit 1223 in this case calculates the comparison target value M _{k + 1} by further subtracting the collision avoidance interference source number NC _t in addition to the current interference wave number NI _G from the maximum value NI _t within the period. To do.

Further, when using the frequency-corresponding maximum value NI _{t (x%)} and the collision avoidance interference source number NC _t , the comparison target value calculation unit 1223 uses the following Equation 9 to calculate the next (k + 1) th allocation slot. The comparison target value M _{k + 1} used to determine whether or not to transmit can be calculated in accordance with the timing of.
M _{k + 1} = NI _{t (x%)} − (NI _G + NC _t ) (Equation 9)
That is, the comparison target value calculation unit 1223 in this case further subtracts the collision avoidance interference source number NC _t in addition to the current interference wave number NI _G from the frequency corresponding maximum value NI _{t (x%).} M _{k + 1} is calculated.

The processing of FIG. 9 in this embodiment is as follows. In the receiver 102, the comparison target value calculation unit 1223 uses, as a comparison target value calculation parameter, one of the maximum value NI _t within the period and the frequency-corresponding maximum value NI _{t (x%)} , and the collision avoidance interference source number NC. _t and the current interference wave number NI _G are acquired (step S201). That is, the comparison target value calculation unit 1223 in this case acquires three comparison target value calculation parameters.
Next, the comparison target value calculation unit 1223 calculates the comparison target value M _{k + 1} by using the three comparison target value calculation parameters acquired in step S201 according to the above formula 8 or formula 9 (step S202).
And the notification part 123 transmits the comparison object value notification message which shows the comparison object value _{Mk + 1} calculated by step S202 to the control station 300 (step S203).

Also, the same processing as described above is performed in the receiver 202 of the terminal device 200 in the present embodiment. That is, the comparison target value calculation unit 2223 calculates one of the maximum value NI _t within the period and the frequency-corresponding maximum value NI _{t (x%)} , the collision avoidance interference source number NC _t, and the current interference wave number NI _G. And obtained as a comparison target value calculation parameter (step S201).
The comparison target value calculation unit 2223 uses the three comparison target value calculation parameters acquired in step S201 to calculate the comparison target value M _{k + 1 according} to the above formula 8 or formula 9 (step S202).
Then, the notification unit 2123 transmits a comparison target value notification message indicating the comparison target value M _{k + 1} calculated in step S202 to the control station 300 via the base station 100 (step S203).

The in-period maximum value NI _t and the frequency-corresponding maximum value NI _{t (x%)} include the number of interference waves when the receiver 102 is not receiving data. That is, the maximum value NI _t within the period and the frequency-corresponding maximum value NI _{t (x%)} include the number of interference waves coming from an interference source having a collision avoidance function in another system. However, since an interference wave does not arrive from an interference source having a collision avoidance function when the receiver 102 is receiving data, it does not have to be included in the interference wave to be removed. Therefore, as shown by (Equation 8) or (Equation 9), by further subtracting the collision avoidance interference source number NC _t , the comparison target value is set according to the number of interference sources of other systems having a collision avoidance function. It is possible to reduce the transmission allocation with higher frequency utilization efficiency.

Further, the comparison target value calculation parameter as the collision avoidance interference source number NC _t in the present embodiment also varies according to the temporal change of the interference state. Therefore, also in the present embodiment, it is possible to perform transmission allocation appropriately by dynamically following the temporal variation of the interference situation.

<Fifth Embodiment>
Subsequently, a fifth embodiment will be described. In the fifth embodiment, learning is performed on the appearance pattern of the maximum value of the interference wave number from another system, and the maximum value of the interference wave number estimated according to the learning is acquired as one of the comparison target value reference parameters.

The comparison target value calculation unit 1223 of the receiver 102 acquires the maximum value NI _{k of the} number of interference waves from other systems in the kth allocation slot. The comparison target value calculation unit 1223 acquires a plurality of maximum values NI _k for a predetermined past t seconds. In addition, the comparison target value calculation unit 1223 calculates the matrix NM _tk (= NI _k , NI _k−1 , NI _k−2 , NI _k−3 ...) For the plurality of maximum values NI _k acquired in t seconds. To do.
The comparison target value calculation unit 1223 performs learning using the matrix NM _tk and obtains the maximum value (estimated maximum value NIP _{k + 1} ) of the number of interference waves at the timing of the next (k + 1) th allocation slot. As an example, the comparison target value calculation unit 1223 can determine the occurrence frequency for each possible combination of the matrix NM _tk and can estimate the estimated maximum value NIP _{k + 1} according to the determined occurrence frequency.
Note that the above method is merely an example, and the method of learning and estimation of the estimated maximum value NIP _{k + 1} performed by the comparison target value calculation unit 1223 is not particularly limited.
Further, the comparison target value calculation unit 1223 of the present embodiment also acquires the current interference wave number NI _G as a comparison target value reference parameter.

The comparison object value calculating unit 1223 in the same receiver 102 uses the estimated maximum value was obtained as compared value calculated parameter as the NIP k + ₁ and the current interference wave number NI _G, by Equation 10 below Then, a comparison target value M _{k + 1} used to determine whether transmission is possible or not is calculated in correspondence with the timing of the next (k + 1) th allocation slot.
M _{k + 1} = NIP _{k + 1} −NI _G (Expression 10)
That is, the comparison target value calculation unit 1223 in the present embodiment calculates the comparison target value M _{k + 1} by subtracting the current interference wave number NI _G from the estimated maximum value NIP _{k + 1} .

The processing of FIG. 9 in this embodiment is as follows. In the receiver 102, the comparison target value calculation unit 1223 acquires the estimated maximum value NIP _{k + 1} and the current interference wave number NI _G as the comparison target value calculation parameters (step S201).
Next, the comparison target value calculation section 1223 uses the estimated maximum value _{NIP k + 1} obtained as comparison object value calculated parameter in step S201 and the current interference wave number NI _G, compared by the formula 10 of the target value _{M k + 1} Is calculated (step S202).
And the notification part 123 transmits the comparison object value notification message which shows the comparison object value _{Mk + 1} calculated by step S202 to the control station 300 (step S203).

Also, the same processing as described above is performed in the receiver 202 of the terminal device 200 in the present embodiment. That is, the comparison target value calculation unit 2223 acquires the estimated maximum value NIP _{k + 1} and the current interference wave number NI _G as the comparison target value calculation parameters (step S201).
The comparison target value calculation unit 2223 uses the estimated maximum value NIP _{k + 1} and the current interference wave number NI _G acquired as the comparison target value calculation parameters in step S201 to calculate the comparison target value M _{k + 1 according} to the above equation 10. (Step S202).
Then, the notification unit 2123 transmits a comparison target value notification message indicating the comparison target value M _{k + 1} calculated in step S202 to the control station 300 via the base station 100 (step S203).

The estimated maximum value NIP _{k + 1} is obtained according to the appearance pattern of the maximum number of interference waves for each assigned slot in a certain period (t seconds). For this reason, the appearance pattern of the maximum number of interference waves in a certain period also changes according to the state of the interference waves received by the receiver. The comparison target value calculation parameter as the estimated maximum value NIP _{k + 1} also varies according to the temporal change of the interference state. Therefore, also in the present embodiment, it is possible to perform transmission allocation appropriately by dynamically following the temporal variation of the interference situation.
Note that this embodiment is effective in a communication environment where the appearance pattern of interference waves received by one receiver is stable within a certain range, for example, the position of the terminal device 200 is fixed to some extent. It is.

In each of the embodiments described above, the acquisition of the comparison target value calculation parameter and the calculation of the comparison target value using the comparison target value calculation parameter are performed by the receiver. However, the receiver may transmit a parameter necessary for calculating the comparison target value to the control station 300, and the control station 300 may calculate the comparison target value.
For example, in the case of the first embodiment, the receiver transmits the reception error rate RI to the control station 300, and the control station 300 calculates the comparison target value using Equation 2 using the received reception error rate RI. Can be configured to Alternatively, the receiver transmits reception result data indicating successful reception and error for each allocation slot to the control station 300, and the control station 300 receives a reception error that is a comparison target value calculation parameter based on the received reception result data. It is also possible to calculate the rate RI and calculate the comparison target value.
In the case of the second embodiment, the receiver transmits the maximum value NI _t within the period acquired as the comparison target value calculation parameter and the current interference wave number NI _G to the control station 300, and the control station 300 The comparison target value can be calculated by Expression 6 using the received maximum value NI _t and the interference wave number NI _G within the period. Alternatively, the receiver notifies the control station 300 of the number of interference waves for each assigned slot, and the control station 300 uses the notified number of interference waves for each assigned slot to obtain the maximum value NI _t within the period and the current number of interference waves NI. _It is also possible to obtain _G and calculate the comparison target value.

  In addition, you may make it implement | achieve the base station 100, the terminal device 200, the control station 300, etc. in embodiment mentioned above with a computer. In that case, a program for realizing this function may be recorded on a computer-readable recording medium, and the program recorded on this recording medium may be read into a computer system and executed. Here, the “computer system” includes an OS and hardware such as peripheral devices. The “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. Furthermore, the “computer-readable recording medium” dynamically holds a program for a short time like a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line. In this case, a volatile memory of a computer unit serving as a server or a client in that case may be included that holds a program for a certain period of time. Further, the program may be for realizing a part of the functions described above, and may be a program capable of realizing the functions described above in combination with a program already recorded in the computer system. You may implement | achieve using programmable logic devices, such as FPGA (Field Programmable Gate Array).

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes designs and the like that do not depart from the gist of the present invention.

DESCRIPTION OF SYMBOLS 100 ... Base station, 101 ... Transmitter, 102 ... Receiver, 111 ... External communication interface, 112 ... Signal transmission part, 121 ... External communication interface, 122 ... Signal reception part, 123 ... Notification part, 200 (200-1, 200-2, 200-3) ... terminal device, 201 (201-1, 201-2, 201-3) ... transmitter, 202 (202-1, 202-2, 202-3) ... receiver, 211 ... External communication interface, 212 ... signal transmission unit, 221 ... external communication interface, 222 ... signal reception unit, 224 ... comparison target value calculation unit, 300 ... control station, 301 ... reception unit, 302 ... transmission allocation unit, 303 ... transmitter Control unit 304 ... storage unit 305 ... transmission unit 321 ... interference wave number acquisition unit 322 ... interference relation information acquisition unit 323 ... comparison target value acquisition unit 324 ... transmission Rejection determination unit, 325 ... transmission history information update unit, 341 ... transmission history information storage unit, 342 ... interference status information storage unit, 343 ... comparison target value information storage unit, 400 ... lower network, 1121 ... signal storage unit, 1122 ... Transmission control unit, 1221 ... interference compensation unit, 1222 ... interference wave number detection unit, 1223 ... comparison target value calculation unit, 2121 ... signal storage unit, 2122 ... transmission control unit, 2123 ... notification unit, 2221 ... interference compensation unit, 2222 ... Interference wave number detection unit, 2223 ... comparison target value calculation unit, 2224 ... signal discrimination unit

Claims (8)

A communication control method in a communication system comprising a communication control device, a plurality of transmitters and a plurality of receivers for performing wireless communication,
An interference wave number detection step in which the receiver detects an interference wave number received from a system other than the communication system; and
An interference relationship information acquisition step in which the communication control apparatus acquires interference relationship information indicating an interference relationship in the transmitter and the receiver;
A comparison target value calculating step in which the receiver or the communication control device calculates a comparison target value based on an interference wave condition parameter that varies depending on the condition of the interference wave received by the receiver;
The communication control device determines whether or not transmission should be permitted in order from the transmitter with the least number of transmission opportunities in the past, and the determination target transmitter performs transmission for each determination target transmitter In this case, the remaining interference wave number that can be removed by the receiver is calculated based on the interference wave number and the interference relationship information, and the transmitter that has already been determined to permit transmission The condition that both the number of residual interference waves that can be removed for each receiver that is the destination and the number of residual interference waves that can be removed from the receiver that is the destination of the determination target transmitter are greater than or equal to the comparison target value A communication control method comprising: a transmission permission / inhibition determining step that determines that transmission should be permitted if the condition is satisfied, and that transmission should not be permitted if the condition is not satisfied. The comparison target value calculating step includes:
A reception error rate based on the number of slots that failed to be received among the slots transmitted to the receiver is acquired as the interference wave status parameter, and a constant according to a comparison result between the reception error rate and a predetermined threshold value The communication control method according to claim 1, wherein the comparison target value is calculated by adding or subtracting to the comparison target value so far. The comparison target value calculating step includes:
Corresponding to the maximum value in the period, which is the maximum value of the number of interference waves detected for each assigned slot assigned to the receiver in a certain period before the time of detecting the current number of interference waves, and the time of detection The communication control method according to claim 1, wherein the detected current interference wave number is acquired as the interference wave state parameter, and the comparison target value is calculated by subtracting the current interference wave number from the maximum value in the period. The comparison target value calculating step includes:
Predetermined appearance from the maximum interference wave number per slot, which is the maximum value of the interference wave number detected for each of a plurality of assigned slots assigned to the receiver in a certain period before the time of detecting the current interference wave number The frequency-corresponding maximum value of the maximum number of interference waves per slot excluding those below the frequency and the current interference wave number detected corresponding to the time point to be detected are acquired as the interference wave status parameter, and the frequency response The communication control method according to claim 1, wherein the comparison target value is calculated by subtracting the current interference wave number from a maximum value. The comparison target value calculating step includes:
The number of interference sources having a collision avoidance function in the other system, which is obtained based on the number of interference waves received from the other system when the receiver is receiving and the number of interference waves received from the other system when not receiving, is further determined. The communication control method according to claim 3, wherein the comparison target value is acquired as a parameter, and the comparison target value is calculated by further subtracting the number of interference sources. The comparison target value calculating step includes:
Estimated based on the occurrence pattern of the maximum interference wave number per slot, which is the maximum value of the interference wave number detected for each of a plurality of assigned slots assigned to the receiver in a certain period before the current interference wave number is detected. Obtaining an estimated slot-unit interference wave maximum value in the next assigned slot and a current interference wave number detected corresponding to the detection time point as the interference wave status parameter, from the estimated slot-unit interference wave number maximum value The communication control method according to claim 1, wherein the comparison target value is calculated by subtracting the current interference wave number. A communication system comprising a communication control device, a plurality of transmitters and a plurality of receivers for performing wireless communication,
In the receiver, an interference wave number detection unit that detects an interference wave number received from a system other than the communication system;
In the communication control device, an interference relationship information acquisition unit that acquires interference relationship information indicating an interference relationship in the transmitter and the receiver;
In the receiver or the communication control device, a comparison target value calculation unit that calculates a comparison target value using an interference wave situation parameter that changes according to the situation of the interference wave received by the receiver;
In the communication control apparatus, it is determined whether or not transmission should be permitted in order from the transmitter with the least number of transmission opportunities in the past, and the transmitter to be determined has transmitted for each transmitter to be determined. In this case, the remaining interference wave number that can be removed by the receiver is calculated based on the interference wave number and the interference relationship information, and the transmitter that has already been determined to permit transmission The condition that both the number of residual interference waves that can be removed for each receiver that is the destination and the number of residual interference waves that can be removed from the receiver that is the destination of the determination target transmitter are greater than or equal to the comparison target value A communication system comprising: a transmission permission / rejection determination unit that determines that transmission should be permitted if the condition is satisfied and determines that transmission should not be permitted if the condition is not satisfied. A communication control apparatus in a communication system including a plurality of transmitters and a plurality of receivers for performing wireless communication,
An interference wave number acquisition unit for acquiring the interference wave number detected by the receiver for the number of interference waves detected by the receiver and received from a system other than the communication system;
An interference relationship information acquisition unit for acquiring interference relationship information indicating an interference relationship in the transmitter and the receiver;
A comparison target value acquisition unit that acquires a comparison target value that is calculated by using an interference wave status parameter that varies depending on the status of the interference wave received by the receiver;
This is to determine whether or not transmission should be permitted in order from the transmitter with the fewest transmission opportunities in the past. For each transmitter to be determined, the receiver removes when the transmitter to be determined transmits. A receiver whose destination is a transmitter that has already been determined to permit transmission, by calculating the remaining number of remaining interference waves, which is the remaining number of possible interference waves, based on the number of interference waves and the interference relation information Transmission is performed when the condition that both the number of remaining interference waves that can be removed and the number of remaining interference waves that can be removed by the receiver that is the destination of the determination target is greater than or equal to the comparison target value is satisfied. A communication control apparatus comprising: a transmission permission / inhibition determining unit that determines that permission should be permitted and that transmission should not be permitted when the condition is not satisfied.

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