JP2021022913A - Controller and control method - Google Patents

Abstract

To provide a controller and a control method, capable of appropriate channel allocation considering interference.SOLUTION: A controller for supporting a first radio system and performing channel allocation to terminals belonging to a first network comprises: a reception unit that acquires a classification result obtained by classifying interference detected at each of a plurality of channels into first interference from a radio device supporting the first radio system and belonging to the first network and second interference differing from the first interference; and a control unit that on the basis of the sum of an out-of-management traffic amount for each of the plurality of channels determined on the basis of an interference amount of the second interference and a managed traffic amount to be distributed to the terminals, determines a managed traffic amount for each channel and, on the basis of the managed traffic amount, determines the number of terminals to be allocated to each of the plurality of channels.SELECTED DRAWING: Figure 4

Description

The present disclosure relates to a control device and a control method.

An unlicensed band (unlicensed band) may be used for communication between wireless communication devices (for example, between a base station and a terminal). Since the unlicensed band is used by various wireless systems, interference may occur due to multiple factors.

For example, Patent Document 1 describes a wireless communication system that determines channel allocation so as to minimize the amount of interference when allocating channels used for communication to a plurality of base stations.

Japanese Unexamined Patent Publication No. 2013-81089

However, there is room for consideration regarding appropriate channel allocation in consideration of interference.

The non-limiting examples of the present disclosure contribute to the provision of a control device capable of performing appropriate channel allocation in consideration of interference, and a control method.

The control device according to an embodiment of the present disclosure is a control device that supports a first wireless system and allocates channels to terminals belonging to the first network, and detects interference detected in each of a plurality of channels. A receiver that supports the first wireless system and acquires classification results classified into a first interference from a wireless device belonging to the first network and a second interference different from the first interference. The management for each of the channels is based on the sum of the unmanaged traffic amount of each of the plurality of channels determined based on the interference amount of the second interference and the managed traffic amount distributed to the terminal. It includes a control unit that determines the amount of internal traffic and determines the number of the terminals to be allocated to each of the plurality of channels based on the amount of internal traffic.

The control method according to an embodiment of the present disclosure is a control method that supports a first wireless system and allocates channels to terminals belonging to the first network, and interferes detected in each of a plurality of channels. , The first radio system is supported, and the classification result classified into the first interference from the radio device belonging to the first network and the second interference different from the first interference is acquired, and the classification result is obtained. The amount of managed traffic for each of the channels is based on the sum of the amount of unmanaged traffic of each of the plurality of channels determined based on the amount of interference of the second interference and the amount of managed traffic distributed to the terminals. Is determined, and the number of the terminals to be assigned to each of the plurality of channels is determined based on the amount of traffic in the management.

Note that these comprehensive or specific embodiments may be realized in a system, device, method, integrated circuit, computer program, or recording medium, and the system, device, method, integrated circuit, computer program, and recording medium. It may be realized by any combination of.

According to one embodiment of the present disclosure, channel allocation that improves frequency utilization efficiency can be performed.

Further advantages and effects in one embodiment of the present disclosure will be apparent from the specification and drawings. Such advantages and / or effects are provided by some embodiments and features described herein and drawings, respectively, but not all need to be provided in order to obtain one or more identical features. There is no.

The figure which shows the outline of the wireless system including LPWA A block diagram showing a configuration example of a network according to an embodiment of the present disclosure. A block diagram showing a configuration example of a base station according to an embodiment of the present disclosure. A block diagram showing a configuration example of a centralized control server according to an embodiment of the present disclosure. The figure which shows the 1st example of the classification result of interference in one Embodiment of this disclosure. The figure which shows the 1st example of the distribution result of the packet transmission rate in one Embodiment of this disclosure. The figure which shows the 2nd example of the distribution result of the packet transmission rate in one Embodiment of this disclosure. A flowchart showing a first example of channel allocation according to an embodiment of the present disclosure. The figure which shows an example of the distribution result of the packet transmission rate in the 2nd example of channel allocation. A flowchart showing a second example of channel allocation according to an embodiment of the present disclosure. The figure which shows the 2nd example of the classification result of interference in one Embodiment of this disclosure. The figure which shows the 3rd example of the distribution result of the packet transmission rate in one Embodiment of this disclosure. A flowchart showing a third example of channel allocation according to an embodiment of the present disclosure. The figure which shows the example of the determination of the allocation order of the terminal in one Embodiment of this disclosure. A flowchart showing a process of determining a terminal allocation order according to an embodiment of the present disclosure.

Preferred embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. In the present specification and the drawings, components having substantially the same function are designated by the same reference numerals, so that duplicate description will be omitted.

(One Embodiment)
In the unlicensed band (for example, frequency bands such as 920 MHz band, 2.4 GHz band, and 5 GHz band), in addition to wireless LAN (Local Area Network) communication, IoT (Internet of Things) terminals and / or M2M (Machine) to Machine) Communication is performed by the terminal.

For example, in IoT and / or M2M, the use of a wireless communication technology called LPWA (Low Power Wide Area), which enables communication in a wide area with low power consumption, is being studied.

There are a plurality of methods (standards) in LPWA. For example, the LPWA communication method includes a first communication method in which communication is performed using a spread spectrum method and a second communication method in which communication is performed without using a spread spectrum method. The first communication method includes, for example, a communication method called "LoRa". Further, the second communication method includes, for example, a communication method called "Wi-SUN (Wireless Smart Utility Network)".

Terminals that support LPWA system communication (hereinafter, may be referred to as "LPWA terminals") are not limited to terminals owned by users, but are mounted on various devices. For example, LPWA terminals are also mounted on televisions, air conditioners, washing machines, home appliances such as refrigerators, and mobile transportation such as vehicles.

Since the unlicensed band is used by various systems including, for example, Wi-fi (registered trademark) and RFID (Radio Frequency IDentifier) in addition to LPWA, traffic increases rapidly and interference increases.

Therefore, for example, in an LPWA system, when allocating a channel used for communication of an LPWA terminal, it is desirable to consider interference within the same system and interference from other systems.

FIG. 1 is a diagram showing an outline of a wireless system including LPWA.

In FIG. 1, a group # 1, a group # 2, and a group # 3 are shown. Each group includes a plurality of devices.

Groups # 1 and # 2 are both LPWA systems. However, the network # 1 (NW # 1) to which each device of the group # 1 belongs is different from the network # 2 (NW # 2) to which each device of the group # 2 belongs. For example, NW # 1 and NW # 2 are the same LPWA system and are networks operated by different operators. The LPWA system of group # 2 is an LPWA system of a network (unmanaged network) not managed by group # 1.

Group # 1 includes devices belonging to NW # 1 and having a wired or wireless connection with NW # 1. For example, group # 1 includes gateways # 1 (GW # 1) and GW # 2 of the LPWA system and terminals # 1 to # 3. In addition, group # 1 includes a centralized control server # 1 that centrally controls GW and the like via NW # 1.

Group # 2 includes devices belonging to NW # 2 and having a wired or wireless connection with NW # 2. For example, group # 2 includes GW # 3 of the LPWA system and terminals # 4 to # 5. Further, the group # 2 includes a centralized control server # 2 that centrally controls the GW and the like via the NW # 2.

The number of devices in groups # 1 and # 2 in FIG. 1 is an example, and the present disclosure is not limited to this. For example, the number of GWs included in one group may be 3 or more. Further, the number of terminals included in one group may be 1 or 4 or more.

Further, other devices may be connected to the NW of each group. For example, group # 1 may include a relay station that relays wireless communication between GW # 1 and / or GW # 2 and terminals # 1 to # 3. A similar relay station may be included in group # 2.

Group # 3 is a wireless system different from the wireless system (LPWA system) of group # 1. The radio system of group # 3 is a radio system of an unmanaged network that is not managed by group # 1. Group # 3 wireless systems are, for example, RFID and Wi-fi. Group # 3 includes RFID readers / writers, RFID tags, terminals using Wi-fi, and the like. The wireless system of group # 3 may include an LTE (Long Term Evolution) system, a radar system, and the like. Further, group # 3 may include noise sources other than wireless systems, such as general household appliances, lighting equipment, and heavy equipment.

The network configuration shown in FIG. 1 and / or the configuration of the device is an example, and the present disclosure is not limited to this.

The above-mentioned GW may have a function of an interference monitoring device for measuring interference. The "base station" in the following description corresponds to a GW having the function of an interference monitoring device.

Further, each network shown in FIG. 1 may include a device different from the device shown in FIG. In that case, the other device may have some or all of the functions of the device shown in FIG. For example, when a relay station is provided in group # 1 or group # 2, the relay station may have the function of an interference monitoring device. Further, the relay station may have a GW function and an interference monitoring function. Alternatively, the relay station has the function of an interference monitoring device and does not have to have the function of GW.

Each radio device in groups # 1 to # 3 uses a common system band (eg, unlicensed band). Therefore, each wireless device included in the groups # 1 to # 3 receives interference from other wireless devices. Hereinafter, the interference received by the wireless devices included in the group # 1 will be described as an example.

For example, the signal transmitted by the first wireless device (for example, terminal # 2) included in group # 1 to the second wireless device (for example, GW # 1) included in group # 1 is group # 1. It may also be received (detected) by a third wireless device (for example, GW # 2) included in the above. In this case, in the third wireless device, interference caused by the signal may occur. In the following, an interference signal received by a radio device belonging to NW # 1 from another radio device belonging to NW # 1 may be described as an "in-management signal". For example, the intra-managed signal supports communication in an LPWA system and corresponds to interference that a radio device belonging to NW # 1 supports communication in an LPWA system and receives from another radio device belonging to NW # 1.

Also, for example, the signal transmitted by the wireless device (eg, terminal # 5 and / or RFID reader / writer) included in group # 2 and / or group # 3 is the wireless device included in group # 1 (eg, eg). Causes interference in terminal # 1). In the following, the interference that a radio device belonging to NW # 1 receives from a radio device that does not belong to NW # 1 may be described as "unmanaged interference". For example, unmanaged interference corresponds to interference that supports communication in an LPWA system and is received by a radio device belonging to NW # 1 from a radio device that does not belong to NW # 1. Alternatively, the uncontrolled interference corresponds to the interference component excluding the in-controlled signal from the detected signals (interference).

Uncontrolled interference may be further classified based on the factors of interference.

For example, a signal transmitted by a radio device (eg, terminal # 4) included in group # 2 causes interference in a radio device (eg, GW # 1) included in group # 1. In the following, the interference that the radio device belonging to NW # 1 receives from the radio device belonging to NW # 2 may be described as "radio wave interference" among "unmanaged interference". For example, "radio interference" corresponds to interference that a radio device belonging to NW # 1 supports communication of an LPWA system and supports communication of an LPWA system and receives from a radio device belonging to NW # 2 different from NW # 1. To do.

Also, for example, a signal transmitted by a radio device (eg, RFID reader / writer) included in group # 3 causes interference in the radio device (eg, GW # 1) included in group # 1. In the following, the interference that a wireless device belonging to NW # 1 that supports communication of an LPWA system receives from a wireless device that supports a wireless system different from the LPWA system is described as "environmental noise" among "unmanaged interference". May be done.

As shown with FIG. 1 as an example, the LPWA system uses a common system bandwidth with a radio system different from the LPWA system and / or the same LPWA system belonging to a different network. Therefore, it is desirable to consider interference in the channel.

For example, a method is conceivable in which the terminal randomly selects a channel from a plurality of candidate channels at the time of a transmission attempt, and when the carrier sense determines that the channel is an empty channel, the terminal executes signal transmission on the channel. .. However, in this method, since the channel having a relatively high rate of unmanaged interference described above may be selected, the probability of signal transmission is reduced. Alternatively, in this method, the reception error rate increases due to the influence of interference.

Further, for example, a method in which the received power of each channel is measured on the base station side and the channel having a relatively low received power is preferentially assigned to the terminal can be considered. However, in this method, it is difficult to properly allocate channels because the measured received power indicates the power of a signal in which unmanaged interference and in-managed signals are mixed.

Non-limiting examples of the present disclosure include a control device capable of performing appropriate channel allocation in consideration of interference by performing channel allocation to terminals based on the results obtained by classifying interference. , Contributes to the provision of control methods.

<Network configuration example>
FIG. 2 is a block diagram showing a configuration example of a network (NW) according to the present embodiment. The network shown in FIG. 2 includes a base station 10 (base stations 10-1 to 10-L (L is an integer of 1 or more)), a centralized control server 20, and terminals # 1 to #M (M is 1 or more). Integer) is included. Each device included in the network shown in FIG. 2 corresponds to the device of group # 1 shown in FIG. 1, and supports communication of, for example, an LPWA system.

The base station 10 wirelessly connects to a terminal (any of terminals # 1 to # M) and performs wireless communication on a channel assigned to the terminal. Further, the base station 10 performs interference monitoring on each of the available channels and outputs the interference classification result to the centralized control server 20.

The centralized control server 20 connects to the base station 10 by wire and acquires the classification result from the base station 10. Further, the centralized control server 20 may acquire information about a terminal wirelessly connected to the base station 10 from the base station 10. The centralized control server 20 determines the channel to be assigned to the terminal in the base station 10 based on the classification result. The centralized control server 20 outputs allocation information including information on channels to be allocated to terminals to the base station 10.

Terminals # 1 to # M are LPWA terminals that communicate with the base station 10 (any of the base stations 10-1 to 10-L) and the LPWA system, respectively.

<Base station configuration example>
FIG. 3 is a block diagram showing a configuration example of the base station 10 according to the present embodiment. The base station 10 corresponds to, for example, GW # 1 or GW # 2 belonging to NW # 1 shown in FIG.

The base station 10 includes a receiving unit 101, a demodulation / decoding unit 102, an interference classification unit 103, a control unit 104, a control signal generation unit 105, a coding / modulation unit 106, and a transmission unit 107. ..

The receiving unit 101 receives the signal transmitted by the terminal, and performs a predetermined reception process on the received signal. For example, a predetermined reception process includes a frequency conversion process (down-conversion) based on the frequency of the channel assigned to the terminal or the frequency of the channel for transmitting the control signal. The frequency information of the channel assigned to the terminal may be acquired from, for example, the control unit 104.

In addition, the receiving unit 101 receives (detects) a signal in each available channel in the system band (for example, each channel included in the unlicensed band) for interference measurement (interference monitoring). Then, the receiving unit 101 performs a predetermined reception process on the received signal. The predetermined reception process includes, for example, a frequency conversion process based on the frequency of each channel.

The receiving unit 101 outputs the received signal that has undergone the predetermined reception processing to the demodulation / decoding unit 102 and the interference classification unit 103.

The demodulation / decoding unit 102 performs demodulation processing and decoding processing on the received signal acquired from the receiving unit 101 to generate received data. The received data may include an identifier that identifies a terminal belonging to the same NW (NW # 1) as the base station 10.

The interference classification unit 103 classifies the interference in each channel, for example. For example, the interference classification unit 103 monitors the received signal for a predetermined time in one channel, and classifies the above-mentioned in-managed signal and unmanaged interference from the received signal.

For example, the interference classification unit 103 detects the preamble of the received signal. A preamble of the LPWA system is attached to the signal transmitted by the terminal supporting the LPWA system. For example, the interference classification unit 103 calculates the correlation between the preamble and the received signal used in the LPWA system. The preamble used in the LPWA system may be common regardless of the NW to which the terminal from which the received signal is transmitted belongs.

The interference classification unit 103 determines that the source of the received signal is not an LPWA terminal when the result of the correlation between the preamble and the received signal does not have a peak of a predetermined value or more. In this case, the interference classification unit 103 determines that the source of the received signal is a wireless device that supports a wireless system different from the LPWA system, and that the received signal corresponds to environmental noise, which is an example of unmanaged interference. ..

For example, the interference classification unit 103 determines that the source of the received signal is an LPWA terminal when a peak of a predetermined value or more occurs in the result of the correlation between the preamble and the received signal.

Here, the preamble used for the communication of the LPWA system may be common regardless of the NW to which the terminal of the source of the received signal belongs. Therefore, when the interference classification unit 103 determines that the source of the received signal is an LPWA terminal, the NW to which the source belongs is the same NW (NW # 1) as the base station 10 or a different NW (NW # 1) from the base station 10. For example, it is determined whether it is NW # 2) in FIG.

For example, the interference classification unit 103 determines the NW to which the transmission source belongs based on the decoding result of the received signal acquired from the demodulation / decoding unit 102. For example, when the received signal is correctly decoded and the received signal includes an identifier, the interference classification unit 103 determines that the NW to which the source of the received signal belongs is the same NW as the base station 10. On the other hand, for example, the interference classification unit 103 states that when the received signal is not correctly decoded and the received signal does not include an identifier, the NW to which the source of the received signal belongs is different from that of the base station 10. judge.

When the source of the received signal is an LPWA terminal belonging to the same NW # 1 as the base station 10, the interference classification unit 103 determines that the received signal corresponds to the signal in management. When the source of the received signal is an LPWA terminal belonging to a NW different from that of the base station 10, the interference classification unit 103 determines that the received signal corresponds to radio wave interference, which is an example of unmanaged interference.

The classification method in the interference classification unit 103 is not limited to the above-mentioned method based on the preamble detection result of the received signal and the decoding result of the received signal.

For example, the interference classification unit 103 may classify the received signal into an in-control signal and an interference different from the in-managed signal (non-managed interference). In this case, the interference classification unit 103 does not have to classify the unmanaged interference into radio wave interference and environmental noise. For example, the interference classification unit 103 may detect unmanaged interference by classifying the managed signal from the received signal based on the decoding result of the received signal and subtracting the managed signal from the received signal.

The interference classification unit 103 may determine an index representing the traffic amount in each channel from the interference amount of interference obtained as a result of the classification. For example, the traffic volume may be the packet transmission rate in each channel. An example of determining the index in the interference classification unit 103 will be described later.

The interference classification unit 103 performs interference monitoring and outputs notification information indicating the result of classifying the interference to the control unit 104. The notification information may indicate, for example, the interference amount of the classified interference, or may indicate an index determined from the interference amount.

The method of expressing the amount of interference is not particularly limited. For example, the amount of interference may be represented by the average value, the minimum value, or the maximum value of the received signal power (which may be referred to as interference power). Alternatively, the amount of interference may be expressed using the relationship between the received signal power and the time interval (which may be referred to as a monitoring interval) for receiving the received signal. For example, the amount of interference may be represented by a time interval in which the received signal power has a value of a predetermined value or more, or whether or not the time interval in which the received signal power has a value of a predetermined value or more is a predetermined length or more. It may be represented. Further, the representation of the signal in control and the amount of interference in interference outside control may be different from each other or may be common.

The control unit 104 acquires allocation information regarding the channel assigned to the terminal from the centralized control server 20 (see FIGS. 1 and 2) of NW # 1.

The control unit 104 outputs the allocation information to the control signal generation unit 105.

In addition, the control unit 104 controls data communication with the terminal. For example, the received data acquired from the demodulation / decoding unit 102 may be output to an external network (not shown) or another device in NW # 1. Further, the control unit 104 outputs the transmission data addressed to the terminal acquired from the external network or another device in NW # 1 to the coding / modulation unit 106.

The control signal generation unit 105 generates a control signal addressed to the terminal based on the information acquired from the control unit 104. The control signal generation unit 105 outputs the control signal to the coding / modulation unit 106.

The coding / modulation unit 106 performs coding processing and modulation processing on the transmission data acquired from the control unit 104 to generate a transmission signal. Further, the coding / modulation unit 106 performs coding processing and modulation processing on the control signal acquired from the control signal generation unit 105 to generate a transmission control signal. The coding / modulation unit 106 outputs a transmission signal and / or a transmission control signal to the transmission unit 107.

The transmission unit 107 performs a predetermined transmission process on the transmission signal. For example, the predetermined transmission process includes a frequency conversion process (up-conversion) based on the frequency of the channel assigned to the terminal. The allocation information regarding the frequency of the channel assigned to the terminal may be acquired from, for example, the control unit 104.

In addition, the transmission unit 107 performs a predetermined transmission process on the transmission control signal. For example, the predetermined transmission process includes a frequency conversion process (up-conversion) based on the frequency of the channel for transmitting the transmission control signal to the terminal. The channel for transmitting the transmission control signal to the terminal may be, for example, a predetermined channel or a channel currently used for communication with the terminal.

<Centralized control server configuration example>
FIG. 4 is a block diagram showing a configuration example of the centralized control server 20 according to the present embodiment. The centralized control server 20 belongs to, for example, NW # 1 shown in FIG. For example, the centralized control server 20 has a wired connection with the above-mentioned base station 10. Alternatively, the centralized control server 20 may be connected to a network such as the Internet by wire and may be connected to the base station 10 via the network.

The centralized control server 20 includes a receiving unit 201, a control unit 202, and a transmitting unit 203.

The receiving unit 201 receives, for example, information from the base station 10. For example, the information received from the base station 10 may be various information including notification information. Further, the information received from the base station 10 may include information regarding the channel allocation of the base station 10. Information about channel allocation includes, for example, information about terminals that are wirelessly connected to base station 10 and / or terminals that request wireless connection to base station 10. The information about the terminals may include information on the number of terminals and / or the duty ratio of each terminal.

The control unit 202 allocates channels in the base station 10 based on the information received from the base station 10. For example, the control unit 202 determines the number of terminals assigned to each of the channels used by the base station 10 based on the notification information. Alternatively, the control unit 202 may determine the terminals to be assigned to each of the channels based on the determined number of terminals.

An example of channel allocation in the control unit 202 will be described later.

The transmission unit 203 transmits the allocation information indicating the channel allocation result in the control unit 202 to the base station 10.

In the above description, an example in which the configuration shown in FIG. 3 is included in one base station 10 and the configuration shown in FIG. 4 is included in one centralized control server 20 has been described. The present disclosure is not limited to this. For example, the base station 10 may have at least a part of the configuration of the centralized control server 20, or the centralized control server 20 may have at least a part of the configuration of the base station 10. For example, in the network shown in FIG. 2, at least one of the base stations 10 may have the configuration of the centralized control server 20.

For example, the configuration of the base station 10 shown in FIG. 3 is divided into a first device having a communication function of an LPWA system and a second device having a function of a radio wave interference monitoring device (for example, an interference classification unit 103). You can.

Further, in this case, for example, the second device may acquire the decoding result of the received signal in the first device, or output the notification information generated by the second device to the first device. You may. Further, for example, the second device may be in a form of acquiring the received signal received by the receiving unit 101 of the first device instead of having the receiving unit 101.

Further, the functional block of the second device may be included in the relay station. Alternatively, the second device may be connected to a relay station and operated.

<First example of channel allocation>
Next, a first example of channel allocation in the control unit 202 of the centralized control server 20 will be described.

In the following description, the “managed terminal” refers to a terminal belonging to the same network as the centralized control server 20 and the base station 10. In other words, the "managed terminal" refers to a terminal under the control of the network to which the centralized control server 20 belongs. Further, in the following description, the “unmanaged terminal” refers to a terminal and / or a wireless device that is not under the control of the network to which the centralized control server 20 belongs. The "unmanaged terminal" is not limited to the device of the wireless system, and may include a device that is a source of noise.

The interference classification unit 103 of the base station 10 monitors the interference of each channel and classifies the unmanaged interference and the in-managed signal included in the detected interference.

The interference classification unit 103 calculates the average duty ratio of the management terminal from the management signal. For example, the interference classification unit 103 may calculate the average duty ratio based on the number of terminals to be assigned and the length of the time interval in which the control signal is detected.

Interference classifier unit 103 calculates the channel utilization r _i ^u from the interference of unmanaged interference. In addition, _i in the channel utilization rate r _i ^u indicates the index of the channel, and u indicates that r _i is the channel utilization rate of unmanaged interference. For example, when the number of channels is N _CH (N _CH is an integer of 1 or more), i takes any one value of an integer from 0 to N _CH -1. In the following, the channel usage rate determined from the interference amount of unmanaged interference may be described as "channel usage rate of unmanaged interference".

For example, the ratio of the time interval to be monitored to the time interval in which the power of unmanaged interference is equal to or greater than the threshold value may be determined as the channel usage rate of unmanaged interference.

FIG. 5 is a diagram showing a first example of the interference classification result in the present embodiment. The horizontal axis of FIG. 5 indicates the frequency (channel), and the vertical axis indicates the channel usage rate. FIG. 5 shows the channel utilization of unmanaged interference in each of the four channels f0 to f4.

The interference classification unit 103 calculates the packet transmission rate λ _i ^u from the channel usage rate r _i ^{u of} unmanaged interference. In the following, the packet transmission rate converted from the channel usage rate of unmanaged interference may be described as "packet transmission rate of unmanaged interference". Further, the packet transmission rate of unmanaged interference corresponds to an example of the amount of unmanaged traffic determined based on the amount of interference of unmanaged interference. For example, transmit collision rate for packet transmission on the random access may follow a Poisson distribution, the packet transmission rate lambda _i ^u with respect to the channel usage rate r _i ^u are translated by the following equation (1).

By converting to the packet transmission rate, the amount of traffic in each channel can be expressed by addition.

The packet delivery ratio lambda _i ^u unmanaged interference corresponds to the sum of the Duty ratio of the unmanaged terminal. For example, when the duty ratios of unmanaged terminals are the same as each other, the packet transmission rate in a certain channel corresponds to the product of the number of unmanaged terminals using a certain channel and the duty ratio.

However, since the unmanaged terminals are not under the control of the base station 10, the base station 10 cannot grasp the number of unmanaged terminals and the duty ratio while using a certain channel. However, it is possible to estimate the packet transmission rate based on the channel utilization of unmanaged interference.

Next, the control unit 202 of the centralized control server 20 determines the distribution of the packet transmission rate of the managed terminal based on the packet transmission rate of unmanaged interference included in the notification information acquired from the base station 10. For example, the control unit 202, using Equation (2) and (3), determines the packet transmission rate lambda _i ^m in the management terminal in each channel. The packet transmission rate of the managed terminal corresponds to an example of the amount of managed traffic distributed to the managed terminal.

Here, N _CH indicates the total number of channels. For example, in the example of FIG. 5, the N _CH is 4. Further, α is a value for satisfying the equations (2) and (3). Here, λ _total ^m in the equation (3) is the sum of the packet transmission rates of all the managed terminals to be assigned. For example, λ _total ^m may be converted from the in-control signal. For example, λ _total ^m may be determined from the number of managed terminals and the duty ratio of managed terminals. For example, λ _total ^m may be the sum of the packet transmission rates of the managed terminals converted from the channel usage rate of the managed signal before the allocation decision.

FIG. 6 is a diagram showing a first example of the distribution result of the packet transmission rate in the present embodiment. The horizontal axis of FIG. 6 indicates the frequency (channel), and the vertical axis indicates the packet transmission rate. As shown in FIG. 6, the unmanaged interference packet transmission rate lambda _i ^u, the sum of the packet transmission rate lambda _i ^m in the management terminal in each channel shows a constant value alpha. As shown in FIG. 6, by the allocation of packet transmission rate lambda _i ^m are determined, the traffic in each channel becomes equal, thereby improving the frequency use efficiency. The procedure for determining the distribution of packet transmission rate shown in FIG. 6, to determine the packet transmission rate lambda _i ^m to the container formed by uncontrolled interference packet transmission rate lambda _i ^u in the manner of pouring water Therefore, it may be called the "water injection theorem".

Note that FIG. 6 shows an example in which the sum of the packet transmission rate λ _i ^u and the packet transmission rate λ _i ^m is a constant value α in each channel, but the present disclosure is not limited to this. For example, a packet transmission rate lambda _i ^u, the sum of the packet transmission rate lambda _i ^m is to fit in a predetermined range in each channel, the distribution of the packet transmission rate may be determined.

In FIG. 6, an example of packet transmission rate lambda _i ^m is allocated to each channel, the present disclosure is not limited thereto. For example, the unmanaged interference packet transmission rate lambda _i ^u, depending on the size of the packet transmission rate lambda _i ^m, the packet transmission rate lambda _i ^m may be present channel that is not allocated.

FIG. 7 is a diagram showing a second example of the distribution result of the packet transmission rate in the present embodiment. The horizontal axis of FIG. 7 indicates the frequency (channel), and the vertical axis indicates the packet transmission rate. In the example of FIG. 7, largely unmanaged interference packet transmission rate lambda _i ^u in the channel f0 is, for allocation packet transmission rate lambda _i ^m required is relatively small, the packet transmission rate on the channel f0 lambda _i ^m is allocated Not done. Note that FIG. 7 shows an example in which the sum of the packet transmission rate λ _i ^u and the packet transmission rate λ _i ^m is a constant value α in each channel except the channel f0. Not limited. For example, a packet transmission rate lambda _i ^u, the sum of the packet transmission rate lambda _i ^m is to fit in a predetermined range in each channel, the distribution of the packet transmission rate may be determined. In this case, the channel having an upper limit or more packet transmission rate lambda _i ^u defining the predetermined range, the packet transmission rate lambda _i ^m may not be allocated.

In the example of FIG. 6, channels f0 to f3 correspond to channels assigned to terminals, and in the example of FIG. 7, channels f1 to f3 correspond to channels assigned to terminals.

Next, the control unit 202, the packet transmission rate lambda _i ^m, using equation (4), to determine the number n _i ^m within the management terminal to be assigned to the channel corresponding to the index i. Here, d represents the duty ratio of the managed terminal.

For example, if n _i ^m which is determined using equation (4) is not an integer, the control unit 202, rounding up the decimal point, truncation, or may be converted to an integer by such rounding. The control unit 202, based on the total number of management target terminal to assign the n _i ^m and the base station 10 as determined using the equation (4) may determine the number of management target terminal of each channel. For example, a condition that corresponds to the number of the management in the terminal the sum of the number in the management terminal of each channel allocated in the base station 10, equation (4) the determined n _i ^m and in the management terminal of each channel using The number of managed terminals in each channel may be determined so that the condition that the difference from the number is less than or equal to a predetermined value is satisfied.

When the duty ratios of the managed terminals are the same, the number of managed terminals is determined by the equation (4), but the present disclosure is not limited to this. The duty ratio may be different for each managed terminal. For example, the duty ratio may be estimated from the classification result of interference monitoring. Alternatively, a predetermined value may be set for the duty ratio.

The control unit 202 allocates managed terminals to each channel based on the determined number of managed terminals. The allocation method is not particularly limited. For example, it may be randomly assigned, or it may be assigned based on the reception level of each managed terminal.

In the above description, an example of using the channel utilization rate of uncontrolled interference has been shown, but the present disclosure is not limited to this. For example, the channel unused rate of unmanaged interference may be used instead of the channel utilization rate of unmanaged interference.

Further, in the above description, an example of converting the packet transmission rate from the channel usage rate of unmanaged interference has been shown, but the present disclosure is not limited to this. For example, a packet arrival rate or a packet collision rate may be used instead of the packet transmission rate. The method for converting the packet arrival rate or the packet collision rate is not particularly limited, but may be, for example, a method for converting based on the Poisson distribution, as in the packet transmission rate described above. For example, when the packet arrival rate is used, the water injection theorem is applied to the packet arrival rate of unmanaged interference, and the distribution of the packet arrival rate of the managed terminal is determined, as in the case where the packet transmission rate is used. You can. Then, the number of managed terminals assigned to each channel may be determined from the packet arrival rate of the managed terminals.

In the above example, the water injection theorem is applied to the packet transmission rate of uncontrolled interference, but the present disclosure is not limited to this. For example, the packet transmission rate of unmanaged interference may be converted into the number of unmanaged terminals, and the water injection theorem may be applied to the converted number of unmanaged terminals. In this case, as a result of the water injection theorem, the number of managed terminals may be obtained.

However, when converting to the number of unmanaged terminals, the number of unmanaged terminals may be converted to a value that is not an integer. In such a case, the water injection theorem may be applied to a value that is not an integer, or after approximating to an integer by rounding up, rounding down, rounding, etc. after the decimal point, the number of terminals with unmanaged interference that approximates an integer On the other hand, the water injection theorem may be applied.

In addition, when the water injection theorem is applied after converting to the number of terminals, the number of managed terminals obtained may be a value other than an integer. In such a case, channel allocation may be performed based on the number of unmanaged terminals approximated to an integer by rounding up, rounding down, rounding off, or the like.

The channel usage rate, channel unused rate, packet transmission rate, packet arrival rate, packet collision rate, and the number of terminals described above are examples of indicators representing the traffic volume of the channel, but in the present disclosure, the channel is used. Another indicator of traffic volume may be used. The traffic volume of the channel may be replaced with the usage volume of the channel, the frequency of use of the channel, and the like.

An upper limit value may be set for α. For example, when α for satisfying equations (2) and (3) is equal to or greater than the upper limit value α _limit , the control unit 202 allocates the packet transmission rate of the managed terminal so as to satisfy α <α _limit. decide. In this case, i = the sum of each n _i ^m of 0 to N CH _-1 administration in less than the total number of terminals to assign, it is possible that the management in a terminal that is not assigned to the channel exists. In this case, the managed terminal that is not assigned to the channel suspends transmission, so that the duty ratio decreases.

By providing an upper limit value for α, it is possible to suppress an increase in the channel usage rate of each channel and reduce the transmission collision probability.

<Processing flow in the first example of channel allocation>
Next, the processing flow in the first example described above will be described. FIG. 8 is a flowchart showing a first example of channel allocation in the present embodiment.

The base station 10 detects the interference of each channel and classifies the unmanaged interference and the in-managed signal from the detection result (S101).

The base station 10 calculates the average duty ratio from the signal in management (S102).

The base station 10 calculates the channel usage rate for each channel from the interference amount of unmanaged interference of each channel (S103).

The base station 10 calculates the packet transmission rate from the channel usage rate of each channel (S104).

The centralized control server 20 applies the water injection theorem to the packet transmission rate of unmanaged interference, and determines the distribution of the packet transmission rate of the managed terminal (S105).

The centralized control server 20 determines the number of terminals to be assigned to each channel from the allocation of the packet transmission rate of the managed terminals of each channel and the average duty ratio (S106).

The centralized control server 20 determines the managed terminals to be assigned to each channel (S107). Then, the flow ends.

Note that FIG. 8 includes processing in the base station 10 and processing in the centralized control server 20, but at least a part of the processing in the base station 10 may be executed in the centralized control server 20 or centralized. At least a part of the processing in the control server 20 may be executed in the base station 10.

In the first example of channel allocation described above, the control unit 202 of the centralized control server 20 (an example of a control device) is a packet of unmanaged interference of each of a plurality of channels determined based on the amount of interference of unmanaged interference. The packet transmission rate to be distributed to the managed terminals for each channel is determined based on the sum of the transmission rate (an example of the unmanaged traffic volume) and the packet transmission rate to be distributed to the managed terminals (an example of the managed traffic volume). Then, the number of managed terminals to be assigned to the channel is determined based on the packet transmission rate to be distributed to the determined managed terminals. As an example, the control unit 202 applies the water injection theorem to the packet transmission rate to determine the distribution of the packet transmission rate to be distributed to the managed terminals. In this example, since the sum of the unmanaged traffic volume and the managed traffic volume is not biased to a specific channel, it is possible to perform appropriate channel allocation in consideration of interference. Further, since the traffic volume is not biased to a specific channel, the transmission collision probability of the entire network (entire system bandwidth) can be reduced, and the frequency utilization efficiency can be improved.

Further, in the first example of channel allocation described above, since the centralized control server 20 can acquire notification information indicating the classification result of interference monitoring in the base station 10 at any time, the channel allocation can be updated during the operation of the LPWA system. ..

<Second example of channel allocation>
In the first example of channel allocation described above, the interference of each channel in one base station 10 is assigned to the base station 10 based on the classification result of interference monitoring. The present disclosure is not limited to this, and for example, the interference of each channel in the plurality of base stations 10 may be assigned to the channels in the plurality of base stations 10 from the classification result of the interference monitoring. In the following, an example will be described in which the interference of each channel in the two base stations 10 is assigned to the plurality of base stations 10 based on the classification result of the interference monitoring.

FIG. 9 is a diagram showing an example of the distribution result of the packet transmission rate in the second example of channel allocation. FIG. 9 shows an example of monitoring results in two base stations 10 (base station 10-1 and base station 10-2) and an example of distribution of packet transmission rates obtained from the two monitoring results. The horizontal axis of the example of the monitoring result in the two base stations 10 (base station 10-1 and base station 10-2) indicates the frequency (channel), and the vertical axis indicates the channel usage rate. In the channel usage rate r _{k_i} ^u and the packet transmission rate λ _{k_i} ^u , i indicates the index of the channel, k indicates the index for identifying the base station 10, and u indicates the unmanaged interference of r _{k_i} and λ _{k_i} , respectively. Indicates the channel usage rate and packet transmission rate. For example, in the example of FIG. 9, i is an integer from 0 to 3, and k is 1 or 2.

For example, the interference classification unit 103 of the two base stations 10 classifies the interference detected by radio wave monitoring into an unmanaged interference and an in-controlled signal, respectively. Then, the interference classification unit 103 of the two base stations 10 calculates the channel usage rate from the interference amount of unmanaged interference. Then, the interference classification unit 103 calculates the packet transmission rate from the channel usage rate. The method of calculating the packet transmission rate in the interference classification unit 103 is the same as that of the first example of channel allocation described above, and thus the description thereof will be omitted.

Control unit 202 of the centralized control server 20, the water-filling theorem applied to a converted packet sent rates in interference classifier 103 of the two base stations 10, the packet transmission rate lambda _{k_i} ^m in the management terminal in each channel decide. Here, when the water injection theorem is applied, the control unit 202 treats the same channels in a plurality of base stations as if they are different channels. For example, as shown in FIG. 9, the control unit 202 treats the channel f0 of the base station 10-1 and the channel f0 of the base station 10-2 as different channels, and uses the water injection theorem to treat the packet. determining the delivery rate lambda _{k_i} ^m. Since the method of applying the water injection theorem is the same as that of the first example of channel allocation described above, the description thereof will be omitted.

Then, the control unit 202 determines the number of management target terminal to be assigned to the channel corresponding to the index i from the packet transmission rate lambda _{k_i} ^m. Then, the control unit 202 allocates the managed terminals to each channel based on the determined number of managed terminals. In the second example, channel allocation is executed for each of the two base stations 10.

<Processing flow in the second example of channel allocation>
Next, the processing flow in the second example described above will be described. FIG. 10 is a flowchart showing a second example of channel allocation in the present embodiment. In FIG. 10, the same processing as in FIG. 8 is assigned the same number and the description thereof will be omitted as appropriate.

In the flow shown in FIG. 10, the processes S101 to S104 shown in FIG. 8 are executed in each of the plurality of base stations 10.

Then, the centralized control server 20 aggregates the results from the plurality of base stations 10 (S201). For example, the centralized control server 20 aggregates the results by acquiring notification information from a plurality of base stations.

Then, the centralized control server 20 applies the water injection theorem to determine the distribution of the packet transmission rate of the managed terminals of each channel in each of the plurality of base stations 10 (S202).

The centralized control server 20 determines the number of terminals to be assigned to each channel in each of the plurality of base stations 10 from the allocation of the packet transmission rate of the managed terminals of each channel and the average duty ratio (S203).

The centralized control server 20 determines the managed terminals to be assigned to each channel (S204). Then, the flow ends.

Note that FIG. 10 includes processing in the base station 10 and processing in the centralized control server 20, but at least a part of the processing in the base station 10 may be executed in the centralized control server 20 or centralized. At least a part of the processing in the control server 20 may be executed in the base station 10.

In the second example of channel allocation described above, the control unit 202 distributes the packet transmission rate of unmanaged interference of each of the base stations 10 obtained from the classification results of interference monitoring in the plurality of base stations 10 to the managed terminals. Based on the sum of the packet transmission rate to be performed (an example of the amount of traffic in management), the packet transmission rate to be distributed to the management terminals for each channel in each of the plurality of base stations 10 is determined. Then, the control unit 202 determines the number of managed terminals to be assigned to the channels in each of the plurality of base stations 10 based on the packet transmission rate distributed to the managed terminals. In this example, the sum of the traffic volume of unmanaged interference and the traffic volume of the managed terminal is not biased to a specific channel of a specific base station 10, and is kept within a certain range in each channel of each base station 10. Appropriate channel allocation in consideration of interference can be performed for a plurality of base stations 10. Further, since the traffic is not biased to a specific channel of the specific base station 10, the transmission collision probability of the entire network (the entire system band) can be reduced, and the frequency utilization efficiency can be improved.

<Third example of channel allocation>
The first and second examples of channel allocation described above classify the in-managed signal and the out-of-control interference from the interference in each channel, and describe an example in which the channel allocation is executed based on the unmanaged interference. did. In the third example, the unmanaged interference is classified based on the priority, and the channel allocation is executed based on the high priority interference.

In the following, among the uncontrolled interference, the interference having a relatively low priority is described as "low priority interference", and the interference having a relatively high priority is described as "high priority interference".

The classification of low-priority interference and high-priority interference is not particularly limited. When the signal transmission of the radio device (for example, the terminal) included in the NW # 1 including the base station 10 has priority over the signal transmission of the radio device not included in the NW # 1, the radio not included in the NW # 1 Interference by the signal transmitted by the device may correspond to low priority interference. If the signal transmission of the radio device not included in NW # 1 is prioritized over the signal transmission of the radio device included in NW # 1, the interference by the signal transmitted by the radio device not included in NW # 1 is high. It may correspond to priority interference.

For example, low priority interference in an LPWA system includes out-of-band leakage from a radio system that uses a band adjacent to the band used by the LPWA system and is different from the LPWA system. Alternatively, low priority interference in an LPWA system may include out-of-band leakage from a radio system that uses a channel adjacent to the channel used by the LPWA system and is different from the LPWA system. Also, low priority interference in LPWA systems may include equipment noise. For example, low priority interference in an LPWA system may include environmental noise from a wireless system that has a lower priority than the LPWA system among the environmental noises exemplified in FIG.

The high-priority interference in the LPWA system may be, for example, interference among uncontrolled interference excluding the low-priority interference in the LPWA system described above. For example, high priority interference may include radio interference illustrated in FIG. Alternatively, high priority interference, high priority interference, high priority interference on channel f0 includes interference from a radio system that uses the same channel f0 and is different from the LPWA system.

The interference classification unit 103 of the base station 10 classifies the detected interference into an in-control signal and an out-of-control interference, and classifies the out-of-control interference into high-priority interference and low-priority interference.

The method of classifying high-priority interference and low-priority interference in the interference classification unit 103 is not particularly limited. For example, the interference classification unit 103 converts a received signal corresponding to unmanaged interference into a frequency domain, and determines which radio system (a radio system different from the LPWA system) the frequency spectrum of the received signal corresponds to. Good. Then, the interference classification unit 103 may classify the high priority interference and the low priority interference by determining whether or not the determined wireless system has priority over the LPWA system. Information on the frequency spectrum of the other wireless system and the priority of the other wireless system may be stored in advance in the interference classification unit 103.

FIG. 11 is a diagram showing a second example of the interference classification result in the present embodiment. The horizontal axis of FIG. 11 shows the frequency (channel), and the vertical axis shows the channel usage rate. FIG. 11 shows an example in which unmanaged interference in each of the four channels is classified into high priority interference (“H” in FIG. 11) and low priority interference (“L” in FIG. 11).

The interference classification unit 103 calculates the channel usage rate from the interference amount of high priority interference, and calculates the packet transmission rate λ _i ^H from the calculated channel usage rate. The method of calculating the channel usage rate and the packet transmission rate is the same as that of the first example except that the target interference is replaced from the unmanaged interference with the high priority interference. Omit.

Control unit 202 of the centralized control server 20 applies the water-filling theorem for high priority packets transmitted rate obtained from the interference of the interference lambda _i ^H, the packet transmission rate lambda _i ^m in the management terminal in each channel decide. The method of applying the water injection theorem is the same as that of the first example except that the target packet transmission rate is changed from unmanaged interference to high priority interference, and thus the description thereof will be omitted.

FIG. 12 is a diagram showing a third example of the distribution result of the packet transmission rate in the present embodiment. The horizontal axis of FIG. 12 indicates the frequency (channel), and the vertical axis indicates the packet transmission rate. As shown in FIG. 12, the sum of the packet transmission λ _i ^H of high priority interference and the packet transmission rate λ _i ^m shows a constant value α in each channel. By determining the distribution of the packet transmission rate lambda _i ^m as shown in FIG. 12, the traffic in each channel becomes equal, thereby improving the frequency use efficiency.

<Processing flow in the third example of channel allocation>
Next, the processing flow in the third example described above will be described. FIG. 13 is a flowchart showing a third example of channel allocation in the present embodiment. In FIG. 13, the same processing as in FIG. 8 may be assigned the same number and the description thereof may be omitted.

The base station 10 detects the interference of each channel and classifies the unmanaged interference and the in-managed signal from the detection result (S101).

The base station 10 classifies unmanaged interference into high-priority interference and low-priority interference (S301).

The base station 10 calculates the average duty ratio from the signal in management (S102).

The base station 10 calculates the channel usage rate of the high priority interference for each channel from the interference amount of the high priority interference of each channel (S302).

The base station 10 calculates the packet transmission rate of high priority interference from the channel usage rate of high priority interference of each channel (S303).

The centralized control server 20 applies the water injection theorem to the packet transmission rate of high priority interference, and determines the distribution of the packet transmission rate of the managed terminals of each channel (S304).

The centralized control server 20 determines the number of terminals to be assigned to each channel from the allocation of the packet transmission rate of the managed terminals of each channel and the average duty ratio (S106).

The centralized control server 20 determines the managed terminals to be assigned to each channel (S107). Then, the flow ends.

Note that FIG. 13 includes processing in the base station 10 and processing in the centralized control server 20, but at least a part of the processing in the base station 10 may be executed in the centralized control server 20 or centralized. At least a part of the processing in the control server 20 may be executed in the base station 10.

In the third example of channel allocation described above, unmanaged interference is classified into high-priority interference and low-priority interference, and the water injection theorem is applied to the packet transmission rate obtained from the interference amount of high-priority interference. Then, the distribution of the packet transmission rate of the managed terminal is determined. In this example, since the sum of the traffic volume due to the high priority interference and the traffic volume of the managed terminal is not biased to a specific channel, it is possible to perform appropriate channel allocation in consideration of the interference. In addition, since the traffic is not biased to a specific channel, the transmission collision probability of the entire network (entire system bandwidth) can be reduced, and the frequency utilization efficiency can be improved.

Further, in the third example of channel allocation, interference with a system having a high priority can be suppressed, and improvement of frequency utilization efficiency can be realized by coexisting with a system having a low priority.

<Fourth example of channel allocation>
In each of the above examples, the method of allocating the terminal to be assigned to each channel (for example, which terminal is assigned to which channel) is not limited.

For example, in different types of wireless systems including a communication method called "LoRa" (hereinafter, LoRa method) and a communication method called "Wi-SUN" (hereinafter, Wi-SUN method), each terminal The duty ratio and / or the occupied channel width may differ from each other.

For example, in the LoRa method, one channel is used, and communication is performed at a duty ratio larger than that in the Wi-SUN method. In the Wi-SUN system, two channels are used, and communication is performed at a duty ratio smaller than that in the LoRa system.

In the channel allocation, various conditions such as the duty ratio of each terminal and the occupied channel width may be taken into consideration. Further, in the channel allocation, the communication frequency required by each terminal and / or the communication quality of each terminal may be taken into consideration according to the application of the system operating in each terminal.

Hereinafter, in the fourth example, an example of a method of determining which terminal is assigned to which channel in channel allocation will be described. In the following, an example in which the base station 10 executes channel allocation will be described, but the present disclosure is not limited to this, and for example, the centralized control server 20 may execute channel allocation. Alternatively, the base station 10 may execute a part of the procedure described below, and the centralized control server 20 may execute the remaining part. Further, the terminal described below may correspond to the "managed terminal" of the base station 10.

The channel allocation may include step 1 (sorting of terminals) for determining the allocation order of terminals, and procedure 2 for allocating assignable channels to terminals in the order of allocation order determined in step 1. Here, the assignable channels, in the example described above, the management in the amount of traffic allocated to the management within terminal (e.g., the packet transmission rate lambda _{i ^m)} is a channel exists. In the example of FIG. 6, channels f0 to f3 correspond to channels that can be assigned to terminals, and in the example of FIG. 7, channels f1 to f3 correspond to channels that can be assigned to terminals. Here, the channels f0 to f3 may be channels corresponding to the channel numbers # 0 to # 3, respectively.

<Procedure 1: Sorting terminals>
In step 1, the allocation order of the terminals to be assigned (terminals to be assigned) is sorted (sorted). The terminal to be assigned may be, for example, at least a part of the terminals wirelessly connected to the base station 10.

For example, sorting may be regarded as determining the order (allocation order) of terminals to be assigned. In addition, determining the allocation order can be regarded as determining the priority of allocation.

The method of determining the terminal allocation order (sorting method) is not particularly limited. For example, the allocation order may be random or may be determined based on the value of a given parameter. For example, the following five examples can be mentioned. The predetermined parameter may be referred to as "allocation priority".
Example 1: Random order Example 2: Communication quality (for example, reception quality) order Example 3: Order of values of "elapsed time since last successful communication ÷ required communication interval" Example 4: "average value of communication success time interval ÷ required" Order of values of "communication interval" Example 5: Order of values of "maximum value of communication success time interval / required communication interval"

Each example of step 1 will be described later.

Based on the terminal allocation order determined in step 1, in the following procedure 2, the channel to be assigned to the terminal is determined.

<Procedure 2: Assigning channels to terminals>
Assignable channels (candidate channels) are assigned in order from the terminal with the highest allocation order determined in step 1. Which candidate channel is assigned to the allocation target terminal is not particularly limited. For example, the following four methods can be mentioned. The channel (candidate channel) that can be allocated to the terminal to be allocated may correspond to, for example, a channel that can secure the duty ratio and / or the occupied channel width of the terminal to be allocated. For example, in the packet transmission rate lambda _i ^m within the management terminal to be allocated to each channel, the channel often packet transmission rate than packet transmission rate is allocated to the terminal of the assignee is requested, the allocation target terminal It may correspond to an assignable channel (candidate channel). In other words, the channels that can be assigned to each terminal may be different.

(FF (First-Fit))
Among the channels that can be assigned to the terminal to be assigned, the channel with the lowest (lowest) channel number is assigned in order. For example, when channels f1 to f3 in FIG. 6 can be assigned to the terminal to be assigned, channel f1 is assigned to the terminal to be assigned. For example, if channel f0 is not assignable to terminal a and can be assigned to terminal b after terminal a in the terminal allocation order, channel f0 may be assigned to terminal b.

(BF (Best-Fit))
Among the channels that can be assigned to the terminal to be assigned, the channel with the least free space is assigned in order. For example, when channels f1 to f3 in FIG. 6 can be assigned to the terminal to be assigned, channel f2 is assigned.

(WF (Worst-Fit))
Among the channels that can be assigned to the terminal to be assigned, the channel with the most free space is assigned in order. For example, when channels f1 to f3 in FIG. 6 can be assigned to the terminal to be assigned, channel f3 is assigned.

(NF (Next-Fit))
Assign in order from the channel with the lowest channel number. For example, in FIG. 6, channels f0 are assigned in order. For example, when channel f0 is not assignable to terminal a and channel f1 is assigned to terminal a, even if channel f0 can be assigned to terminal b after terminal a in the terminal allocation order. Channel f0 is not assigned to terminal b.

The method in step 2 is not limited to the above four methods. For example, in the method in step 2, the amount of managed traffic of each channel to be distributed to the managed terminals is regarded as an empty box, and the amount of traffic of the managed terminals (for example, the product of the channel width and the size of the duty ratio) is loaded. Corresponds to the method of packing luggage in an empty box when it is regarded as. In other words, the method in step 2 may correspond to a solution of a "binpacking problem" which is a kind of combination optimization problem.

The method in step 2 is not limited to the above four methods, and solutions to other binpacking problems such as greedy method, local search method, genetic algorithm, particle swarm optimization, and column generation method may be applied. ..

Next, each example of step 1 will be described.

(Example 1: Random order)
For example, if the terminal allocation order is randomly determined, each terminal is evenly allocated to the channel in step 2. Therefore, the fact that the allocation order is randomly determined can ensure fairness among terminals from the viewpoint of transmission opportunity.

(Example 2: Order of reception quality)
For example, if the terminal allocation order is determined in the order of poor reception quality (for example, in ascending order of SINR), there are more transmission opportunities (for example, for terminals with poor communication quality, that is, a low probability of successful reception). For example, channel allocation) is given. Therefore, determining the allocation order based on the communication quality can ensure fairness between terminals from the viewpoint of reception success rate.

(Example 3: In order of the value of "elapsed time since the last successful communication / required communication interval")
The "required communication interval" may be, for example, a communication interval required by a function operating in the terminal or a function to be set (for example, an application). For example, in a terminal running an application that executes communication (transmission / reception of data or the like) at least once every 5 minutes, the "required communication interval" is set to 5 minutes. Further, the "elapsed time since the last successful communication" may be, for example, the time elapsed from the time of the latest successful communication (for example, successful transmission or reception of data or the like). The "required communication interval" may be fixed for each terminal or may vary in one terminal.

Next, the value of "elapsed time since the last successful communication / required communication interval" and an example of the allocation order for the value will be described with reference to FIGS. 14 and 15.

FIG. 14 is a diagram showing an example of determining the terminal allocation order in the present embodiment.

FIG. 14 shows terminals 1 to 4 belonging to system 1 and terminals 5 to 8 belonging to system 2. The system 1 is, for example, a system that uses an application with a required communication interval of 5 minutes. The system 2 is, for example, a system that uses an application with a required communication interval of 10 minutes.

Further, FIG. 14 shows "allocation priority" showing the results of dividing the "elapsed time from the previous successful communication" and the "elapsed time from the previous successful communication" by the "required communication interval" for each of the terminals 1 to 8. "Degree" and "priority order" ranked from the one with the highest allocation priority are shown.

In the example shown in FIG. 14, among the terminals 1 to 8, the terminal 3 becomes the first terminal to be assigned, and thereafter, the channels are assigned to the terminals in the order of priority.

FIG. 15 is a flowchart showing a process of determining the terminal allocation order in the present embodiment. The flow shown in FIG. 15 is executed at the base station 10.

The base station 10 clocks the "elapsed time since the last successful communication" of each terminal (S401).

The base station 10 calculates the "allocation priority" when allocating channels (S402).

The base station 10 determines the allocation order (priority order) based on the allocation priority (S403). Then, the flow of FIG. 15 ends.

The requirement related to the communication frequency is determined by determining the allocation order of the terminals based on the value of "elapsed time since the last successful communication ÷ required communication interval" in Example 3 ("allocation priority" in FIG. 14). Fairness between terminals can be ensured from the viewpoint of communication interval. According to the method of Example 3, the channel can be preferentially assigned to the terminal which has poor communication quality, has a long elapsed time since the last successful communication, and has not succeeded in communication for a long time as compared with the required communication interval.

It should be noted that it may be determined whether or not to allocate a channel to the terminal based on the "allocation priority" in Example 3. For example, the base station 10 may determine that the channel is allocated to the terminal whose "allocation priority" is equal to or higher than the threshold value, and that the channel is not allocated to the terminal whose "allocation priority" is less than the threshold value.

(Example 4: In order of "mean value of communication success time interval / required communication interval")
The "communication success time interval" may correspond to the interval between the timing when communication is successful at a certain opportunity and the timing when communication is successful at the next opportunity. Example 4 is an example in which the “elapsed time since the last successful communication” in Example 3 is replaced with the “average value of the communication success time interval”.

For example, the base station 10 measures the communication success time interval of each terminal and determines the average value of the communication success time interval of each terminal. Then, as in Example 3 described above, the base station 10 has a high allocation priority based on the "allocation priority" indicating the result of dividing the "average value of the communication success time interval" by the "required communication interval". The allocation order (priority order) ranked from the side may be determined.

By determining the allocation order of terminals based on the value of "average value of communication success time interval ÷ required communication interval" in Example 4, fairness between terminals from the viewpoint of required communication interval related to communication frequency. You can secure sex. According to the method of Example 4, a channel can be preferentially assigned to a terminal whose communication quality is poor, the communication success time interval is long on average, and communication has not been successful for a long time as compared with the required communication interval.

(Example 5: In order of the value of "maximum value of communication success time interval / required communication interval")
Example 5 is an example in which the “elapsed time since the last successful communication” in Example 3 is replaced with the “maximum value of the communication success time interval”.

For example, the base station 10 measures the communication success time interval of each terminal and determines the maximum value of the communication success time interval of each terminal. Then, as in Example 3 described above, the base station 10 has a high allocation priority based on the "allocation priority" indicating the result of dividing the "maximum value of the communication success time interval" by the "required communication interval". The allocation order (priority order) ranked from the side may be determined.

By determining the allocation order of terminals based on the value of "maximum value of communication success time interval / required communication interval" in Example 5, fairness between terminals in terms of required communication interval related to communication frequency. You can secure sex. According to the method of Example 5, the channel can be preferentially assigned to the terminal whose communication quality is poor, the maximum value of the communication success time interval is long, and the communication has not been successful for a long time as compared with the required communication interval.

In addition, Examples 1 to 5 of Procedure 1 may be used in combination as appropriate. For example, in Example 3, another example in which the allocation order of a plurality of terminals having the same “elapsed time since the last successful communication ÷ required communication interval” (“allocation priority” in FIG. 14) is different from that of Example 3. It may be determined based on. Alternatively, the terminal allocation order may be determined based on a plurality of parameters.

In the fourth example of channel allocation described above, the allocation order of terminals is determined based on a predetermined condition, and channels are allocated according to the determined order. Therefore, frequency utilization efficiency is improved and appropriate according to the conditions for each terminal. Channel allocation can be performed. For example, the condition for each terminal may include a condition regarding the communication quality of the terminal and / or a condition regarding the communication frequency required for the terminal.

In addition, although the above-described embodiment and each example have described the classification of interference in the LPWA system and the method of notifying information on the classified interference, the present disclosure is not limited to this. For example, the present disclosure may also be applied when performing interference monitoring in a wireless system different from the LPWA system.

In addition, each example of allocation in the above-described embodiment may be used in combination. For example, the above-mentioned second example and the third example may be used in combination. In this combination, for example, the centralized control server 20 uses a plurality of base stations based on the interference monitoring classification results of interference of each channel in the plurality of base stations 10 based on the interference having a high priority among the unmanaged interferences. Channel allocation at 10 may be performed. In addition, each example of allocation in the above-described embodiment may be dynamically switched and used.

The notation "... part" in the above embodiment is referred to as "... circuitry", "... device", "... unit", or "... module". It may be replaced with another notation.

Further, the notation "channel" in the above embodiment includes "frequency", "frequency channel", "band", "band", "carrier", "subcarrier", or "(frequency) resource". It may be replaced with the notation of.

Further, the term "calculation" in the above embodiment may be replaced with other terms such as "determination", "estimation", and "derivation".

Further, the term "classification" in the above embodiment may be replaced with other terms such as "separation" and "extraction".

The present disclosure can be realized by software, hardware, or software linked with hardware.

Each functional block used in the description of the above embodiment is partially or wholly realized as an LSI which is an integrated circuit, and each process described in the above embodiment is partially or wholly. It may be controlled by one LSI or a combination of LSIs. The LSI may be composed of individual chips, or may be composed of one chip so as to include a part or all of the functional blocks. The LSI may include data input and output. LSIs may be referred to as ICs, system LSIs, super LSIs, and ultra LSIs depending on the degree of integration.

The method of making an integrated circuit is not limited to LSI, and may be realized by a dedicated circuit, a general-purpose processor, or a dedicated processor. Further, an FPGA (Field Programmable Gate Array) that can be programmed after the LSI is manufactured, or a reconfigurable processor that can reconfigure the connection and setting of the circuit cells inside the LSI may be used. The present disclosure may be realized as digital processing or analog processing.

Furthermore, if an integrated circuit technology that replaces an LSI appears due to advances in semiconductor technology or another technology derived from it, it is naturally possible to integrate functional blocks using that technology. There is a possibility of applying biotechnology.

The present disclosure can be implemented in all types of devices, devices and systems (collectively referred to as communication devices) having a communication function. Non-limiting examples of communication devices include telephones (mobile phones, smartphones, etc.), tablets, personal computers (PCs) (laptops, desktops, notebooks, etc.), cameras (digital stills / video cameras, etc.). ), Digital players (digital audio / video players, etc.), wearable devices (wearable cameras, smart watches, tracking devices, etc.), game consoles, digital book readers, telehealth telemedicines (remote health) Care / medicine prescription) devices, vehicles with communication functions or mobile transportation (automobiles, airplanes, ships, etc.), and combinations of the above-mentioned various devices can be mentioned.

Communication devices are not limited to those that are portable or mobile, but are not portable or fixed, any type of device, device, system, such as a smart home device (home appliances, lighting equipment, smart meters or It also includes measuring instruments, control panels, etc.), vending machines, and any other "Things" that can exist on the IoT (Internet of Things) network.

Communication includes data communication by a combination of these, in addition to data communication by a cellular system, a wireless LAN system, a communication satellite system, and the like.

Communication devices also include devices such as controllers and sensors that are connected or connected to communication devices that perform the communication functions described in the present disclosure. For example, it includes controllers and sensors that generate control and data signals used by communication devices that perform the communication functions of the communication device.

Communication devices also include infrastructure equipment that communicates with or controls these non-limiting devices, such as base stations, access points, and any other device, device, or system. ..

Although various embodiments have been described above with reference to the drawings, it goes without saying that the present disclosure is not limited to such examples. It is clear that a person skilled in the art can come up with various modifications or modifications within the scope of the claims, which naturally belong to the technical scope of the present disclosure. Understood. In addition, each component in the above embodiment may be arbitrarily combined as long as the purpose of disclosure is not deviated.

The specific examples of the present disclosure have been described in detail above, but these are merely examples and do not limit the scope of claims. The techniques described in the claims include various modifications and modifications of the specific examples illustrated above.

The present disclosure is suitable for wireless communication systems.

10 Base stations 101, 201 Reception unit 102 Demodulation / decoding unit 103 Interference classification unit 104, 202 Control unit 105 Control signal generation unit 106 Coding / modulation unit 107, 203 Transmission unit 20 Centralized control server

Claims (9)

A control device that supports a first wireless system and allocates channels to terminals belonging to the first network.
The interference detected in each of the plurality of channels supports the first radio system, and the first interference from the radio device belonging to the first network and the second interference different from the first interference. The receiver that acquires the classification result classified into and
The managed traffic for each channel is based on the sum of the unmanaged traffic amount of each of the plurality of channels determined based on the interference amount of the second interference and the managed traffic amount distributed to the terminal. Determine the amount,
A control unit that determines the number of terminals to be assigned to each of the plurality of channels based on the amount of traffic in management.
A control device comprising. The interference amount of the second interference correlates with the channel utilization and
The unmanaged traffic amount is any one of the packet transmission rate, the packet arrival rate, and the packet collision rate converted from the channel usage rate.
The control device according to claim 1. Using the water injection theorem, the control unit determines the managed traffic volume for each channel so that the sum of the unmanaged traffic volume and the managed traffic volume falls within a predetermined range.
The control device according to claim 1. The control unit does not allocate the managed traffic amount to channels in which the unmanaged traffic amount is equal to or greater than the upper limit defining the predetermined range.
The control device according to claim 3. The control unit determines the managed traffic amount for each channel so that the sum of the unmanaged traffic amount and the managed traffic amount falls within a predetermined upper limit value or less.
The control device according to claim 1. The receiving unit acquires a plurality of the classification results from the plurality of base stations, and obtains the plurality of classification results.
The control unit determines the amount of traffic in management for each of the channels in each of the plurality of base stations.
The control device according to any one of claims 1 to 5. The amount of unmanaged traffic is based on the amount of interference of a third interference contained in the second interference from a radio device that supports a second radio system having a higher priority than the first radio system. Determined for each channel
The control device according to any one of claims 1 to 6. The control unit determines the terminal to be assigned to each of the plurality of channels based on the communication quality condition of the terminal and / or the communication frequency condition required for the terminal.
The control device according to any one of claims 1 to 7. A control method that supports a first wireless system and allocates channels to terminals belonging to the first network.
The interference detected in each of the plurality of channels supports the first radio system, and the first interference from the radio device belonging to the first network and the second interference different from the first interference. Get the classification result classified as
The managed traffic for each channel is based on the sum of the unmanaged traffic amount of each of the plurality of channels determined based on the interference amount of the second interference and the managed traffic amount distributed to the terminal. Determine the amount,
The number of terminals to be assigned to each of the plurality of channels is determined based on the amount of traffic in management.
Control method.

Images