JP7340338B2 - Base station, wireless communication system, and control method - Google Patents

Description

The present disclosure relates to a base station, a wireless communication system, and a control method.

BACKGROUND ART Bands that do not require a license (unlicensed bands) are sometimes used for communication between wireless communication devices (for example, between a base station and a terminal). Since unlicensed bands are used by various wireless communication systems, it is desirable to allocate frequency channels (hereinafter referred to as channels) in consideration of interference caused by multiple factors.

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

Japanese Patent Application Publication No. 2013-81089

However, there is room for consideration regarding channel allocation to improve frequency usage efficiency.

Non-limiting embodiments of the present disclosure contribute to providing a base station, a wireless communication system, and a control method that can perform channel allocation that improves frequency usage efficiency.

A base station according to an embodiment of the present disclosure includes a classification unit that determines a first channel group in which the amount of interference is greater than a first threshold; and a second channel included in the first channel group; and a control unit that allocates a first terminal using a spread spectrum method.

A wireless communication system according to an embodiment of the present disclosure includes a base station and a terminal wirelessly connected to the base station, the base station having a first a classification unit that determines a group of channels; and a control unit that assigns a terminal to a second channel included in the first channel group; and a transmitter that transmits a transmission signal generated using a spread spectrum method.

A control method according to an embodiment of the present disclosure determines a group of first channels in which the amount of interference is greater than a first threshold, and uses a spread spectrum method for a second channel included in the first channels. Assign the first terminal.

Note that these comprehensive or specific aspects may be realized by a system, an apparatus, a method, an integrated circuit, a computer program, or a recording medium. It may be realized by any combination of the following.

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

Further advantages and effects of an embodiment of the present disclosure will become apparent from the description and drawings. Such advantages and/or effects may be provided by each of the embodiments and the features described in the specification and drawings, but not all need to be provided in order to obtain one or more of the same features. There isn't.

A diagram showing an example of allocation of free channels to LPWA terminals A block diagram showing a configuration example of a base station according to an embodiment of the present disclosure A block diagram showing an example of the configuration of a terminal according to an embodiment of the present disclosure A diagram showing an example of channel allocation in variation 1 of an embodiment of the present disclosure Flowchart illustrating an example of base station processing in variation 1 of an embodiment of the present disclosure A diagram showing an example of interference classification in variation 2 of an embodiment of the present disclosure A diagram showing an example of channel assignment in variation 2 of an embodiment of the present disclosure Flowchart illustrating an example of base station processing in variation 2 of an embodiment of the present disclosure A diagram showing an example of channel allocation in variation 3 of an embodiment of the present disclosure Flowchart illustrating an example of base station processing in variation 3 of an embodiment of the present disclosure A diagram showing an example of interference classification in variation 4 of an embodiment of the present disclosure A diagram showing an example of channel assignment in variation 4 of an embodiment of the present disclosure Flowchart illustrating an example of base station processing in variation 4 of an embodiment of the present disclosure A diagram showing an example of interference classification in variation 5 of an embodiment of the present disclosure A diagram showing an example of channel allocation in variation 5 of an embodiment of the present disclosure Flowchart illustrating an example of base station processing in variation 5 of an embodiment of the present disclosure A diagram illustrating an example of channel assignment when the terminal classification is changed in variation 2 of an embodiment of the present disclosure. Flowchart illustrating an example of processing by a base station when changing the classification of a terminal in variation 2 of an embodiment of the present disclosure

Preferred embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. Note that in this specification and the drawings, components having substantially the same functions are designated by the same reference numerals and redundant explanation will be omitted.

(One embodiment)
In IoT (Internet of Things) and/or M2M (Machine to Machine), the use of a wireless communication technology called LPWA (Low Power Wide Area), which allows communication over a wide area with low power consumption, is being considered.

LPWA is being considered for operation in unlicensed bands. There are multiple methods (standards) for LPWA. For example, LPWA communication methods include a first communication method that performs communication using a spread spectrum method, and a second communication method that performs communication without using a spread spectrum method. The first communication method includes, for example, a communication method called "LoRa." Furthermore, the second communication method includes, for example, a communication method called "Wi-SUN (Wireless Smart Utility Network)."

In the following, a communication method called "LoRa" (hereinafter referred to as "LoRa method") will be mentioned as an example of the first communication method, and a communication method called "Wi-SUN" will be mentioned as an example of the second communication method. The communication method (hereinafter referred to as "Wi-SUN method") is listed below. However, the present disclosure is not limited to the LoRa method and the Wi-SUN method.

Further, hereinafter, a terminal that operates based on the LoRa method will be described as a "LoRa terminal", and a terminal that operates based on the Wi-SUN method will be described as a "Wi-SUN terminal".

Note that in this embodiment, an example will be described in which the LoRa terminal and the Wi-SUN terminal are separate terminals, but the present disclosure is not limited to this. For example, a terminal may be able to operate based on both LoRa and Wi-SUN.

Further, below, an example will be described in which the base station supports both the LoRa method and the Wi-SUN method. However, the present disclosure is not limited thereto. A base station that operates based on the LoRa method and a base station that operates based on the Wi-SUN method may be different base stations. Alternatively, the base station includes a wireless communication device (for example, a gateway) that operates based on the LoRa method, a wireless communication device that operates based on the Wi-SUN method, and a control device that controls these two wireless communication devices. It may have.

In addition to LPWA, unlicensed bands are used by various systems including, for example, Wi-fi (registered trademark) and RF-ID.

Therefore, for example, when assigning channels to LPWA terminals such as LoRa terminals and Wi-SUN terminals, it is desirable to consider interference from the same system and other systems.

For example, the base station performs interference measurement on each available channel of the unlicensed band, and assigns an LPWA terminal to a channel where the amount of interference is less than a predetermined value. Note that, hereinafter, a channel in which the amount of interference is less than a predetermined value may be described as an "empty channel."

FIG. 1 is a diagram illustrating an example of assignment of vacant channels to LPWA terminals. The horizontal axis in FIG. 1 indicates frequency, and the vertical axis indicates power or amount of interference. FIG. 1 shows a channel with a carrier frequency f1, a channel with a carrier frequency f2, a channel with a carrier frequency f3, a channel with a carrier frequency f4, a channel with a carrier frequency f5, and the amount of interference of each channel.

In addition, below, the channel of carrier frequency f1 may be described as channel f1. Channels of other frequencies may also be described in the same manner.

FIG. 1 shows that among channels f1 to f5, channels f1 to f4 have an amount of interference greater than a predetermined value, and channel f5 is an empty channel. Note that although FIG. 1 shows an example in which the amounts of interference of channels f1 to f4 are equal to each other, the amounts of interference of channels f1 to f4 may be different from each other. Furthermore, although FIG. 1 shows an example in which the amount of interference on channel f5 is zero, if the amount of interference on channel f5 is less than a predetermined value, channel f5 may be determined to be an empty channel.

In the case of FIG. 1, the base station assigns LPWA terminals (eg, LoRa terminals and Wi-SUN terminals) to channel f5. A terminal assigned to channel f5 transmits a transmission signal during free time using channel f5. Note that in FIG. 1, the transmission power (value on the vertical axis) of the terminal assigned to channel f5 is an example, and the transmission power of the terminal may be different from the example shown in FIG.

However, in the allocation method of assigning LPWA terminals to vacant channels, the number of vacant channels decreases as traffic and/or interference increases in the available band (for example, the entire unlicensed band). Frequency usage efficiency decreases.

Therefore, non-limiting embodiments of the present disclosure contribute to providing a base station, a control system, and a control method that can perform channel allocation that improves frequency usage efficiency.

The wireless communication system according to this embodiment includes base station 100 shown in FIG. 2 and terminal 200 shown in FIG. 3. The base station 100 and the terminal 200 are included in, for example, an LPWA wireless communication system. For example, base station 100 supports both LoRa and Wi-SUN. Further, for example, the terminal 200 operates based on at least one of the LoRa method and the Wi-SUN method.

<Base station configuration>
FIG. 2 is a block diagram showing a configuration example of base station 100 according to this embodiment. The base station 100 includes a reception section 101, a demodulation/decoding section 102, a communication quality measurement section 103, a preamble detection section 104, an interference classification section 105, an allocation control section 106, a control signal generation section 107, and a code It includes a converting/modulating section 108 and a transmitting section 109.

Receiving section 101 receives a signal transmitted by terminal 200, and performs predetermined reception processing on the received signal. For example, the predetermined reception processing includes frequency conversion processing (downconversion) based on the frequency of the channel assigned to terminal 200. Information on the frequency of the channel assigned to the terminal 200 may be obtained from the assignment control unit 106, for example.

Further, the receiving unit 101 receives signals on each usable channel (for example, each channel included in an unlicensed band) for interference measurement (radio wave environment monitoring). The receiving unit 101 then performs predetermined receiving processing on the received signal. The predetermined reception processing includes, for example, frequency conversion processing based on the frequency of each channel.

Receiving section 101 outputs a received signal that has undergone predetermined reception processing to demodulating/decoding section 102, communication quality measuring section 103, and preamble detecting section 104.

Demodulation/decoding section 102 performs demodulation processing and decoding processing on the received signal obtained from receiving section 101 to generate received data. Demodulation/decoding section 102 outputs the received data to allocation control section 106. Note that the received data may include an identifier that identifies the terminal 200 that belongs to the same NW (Network) as the base station 100. Furthermore, if the terminal 200 that is the source of the received signal is a LoRa terminal, the demodulation process may include despreading process for spectrum spread used in the LoRa system.

Communication quality measuring section 103 generates communication quality information based on the received signal acquired from receiving section 101. The communication quality information may be, for example, the quality of the received signal (for example, Received Signal Strength Indicator (RSSI)). Communication quality measurement section 103 outputs communication quality information to allocation control section 106.

Preamble detection section 104 detects whether a preamble is included in the received signal obtained from reception section 101. Further, if a preamble is included, the preamble detection unit 104 determines the type of preamble included in the received signal.

For example, the preamble detection section 104 calculates the correlation between the preamble used in the LoRa method and the received signal. If a peak of a predetermined value or more occurs in the calculated correlation result, the preamble detection unit 104 determines that the preamble used in the LoRa method is included in the received signal. If the preamble used in the LoRa system is included in the received signal, it is determined that the source of the received signal is the LoRa terminal.

Similar to the example of the LoRa method, the preamble detection section 104 calculates the correlation between the preamble used in the Wi-SUN method and the received signal. If a peak of a predetermined value or more occurs in the calculated correlation, the preamble detection unit 104 determines that the received signal includes a preamble used in the Wi-SUN system. If the preamble used in the Wi-SUN system is included in the received signal, it is determined that the source of the received signal is the Wi-SUN terminal.

Note that the preamble detection unit 104 detects the preamble regardless of whether the transmission source of the received signal is included in the NW to which the base station 100 belongs. In other words, the preamble detection section 104 may determine the type of preamble included in a signal transmitted by a LoRa terminal and a Wi-SUN terminal that are not included in the NW to which the base station 100 belongs.

Further, the preamble detection unit 104 detects a peak that is equal to or greater than a predetermined value in both the result of the correlation between the preamble used in the LoRa method and the received signal, and the result of the correlation between the preamble and the received signal used in the Wi-SUN method. If this does not occur, it is determined that the source of the received signal is neither a LoRa terminal nor a Wi-SUN terminal.

Preamble detection section 104 outputs information indicating whether a preamble is included in the received signal and, if a preamble is included in the received signal, information indicating the type of preamble to interference classification section 105. do. Further, preamble detection section 104 outputs the received signal acquired from reception section 101 to interference classification section 105.

The interference classification section 105 classifies interference in each channel, for example. For example, the interference classification section 105 performs classification by monitoring received signals for a predetermined period of time in one channel. For example, the interference classification unit 105 may determine differences in transmission sources of received signals within a predetermined period of time. The interference classification section 105 calculates the ratio of the time of the received signal for each transmission source to a predetermined time, and classifies the interference in each channel. For example, the interference classification section 105 may classify the transmission source of a signal that causes dominant interference in the interference of each channel. Here, in each channel, the dominant interference may correspond to, for example, a result of monitoring a received signal for a predetermined period of time, in which a proportion of the predetermined period of time is equal to or greater than a predetermined proportion.

Interference classification section 105 outputs interference classification results for each channel to allocation control section 106.

Allocation control section 106 determines a channel to be allocated to terminal 200 based on the interference classification result obtained from interference classification section 105. For example, the allocation control unit 106 may change the channels to be allocated to LoRa terminals and Wi-SUN terminals based on the interference classification results.

Further, allocation control section 106 may determine the transmission power control to be performed by terminal 200 according to terminal 200 and the channel allocated to terminal 200.

Note that examples of interference classification results in the interference classification section 105 and examples of channel assignment based on the interference classification results in the allocation control section 106 will be described later.

Allocation control section 106 outputs information regarding the channel allocated to terminal 200 to control signal generation section 107. The information regarding the channel assigned to the terminal 200 may include information regarding the transmission power control to be performed by the terminal 200.

Further, the allocation control unit 106 controls data communication with the terminal 200. For example, the received data obtained from the demodulation/decoding section 102 may be output to a higher-level station (not shown) or another device in the network. Furthermore, allocation control section 106 outputs transmission data addressed to terminal 200, which is acquired from an upper station or another device within the network, to encoding/modulation section 108. Transmission data addressed to terminal 200 may include an identifier indicating the destination.

Control signal generation section 107 generates a control signal addressed to terminal 200 based on the information acquired from allocation control section 106. Control signal generation section 107 outputs a control signal that has been subjected to predetermined signal processing (for example, encoding processing and modulation processing) to transmitting section 109.

Encoding/modulating section 108 performs encoding processing and modulation processing on the transmission data acquired from allocation control section 106, and generates a transmission signal. Encoding/modulating section 108 outputs the transmission signal to transmitting section 109. Note that when the terminal 200 to which the transmission signal is transmitted is a LoRa terminal, the modulation process may include spread spectrum processing used in the LoRa system.

Transmission section 109 performs predetermined transmission processing on the transmission signal obtained from encoding/modulation section 108 . For example, the predetermined transmission processing includes frequency conversion processing (upconversion) based on the frequency of the channel assigned to terminal 200. Information on the frequency of the channel assigned to the terminal 200 may be obtained from the assignment control unit 106, for example.

Further, the transmitting unit 109 performs predetermined transmitting processing on the control signal acquired from the control signal generating unit 107. For example, the predetermined transmission processing includes frequency conversion processing (upconversion) based on the frequency of a channel for transmitting control signals to terminal 200. The channel for transmitting the control signal to terminal 200 may be, for example, a predetermined channel or a channel currently used for communication with terminal 200.

Note that in the above description, an example has been described in which the configuration shown in FIG. 2 is included in one base station 100. This disclosure is not limited thereto. For example, any of two or more devices may include each of the configurations shown in FIG.

For example, the configuration of base station 100 in FIG. and a second device including the interference classification section 105, the allocation control section 106, and the control signal generation section 107. In this case, the first device and the second device may be connected via a network or directly. The first device may for example be called a gateway. The second device may be called an aggregation station, a higher-level station, a control device, or the like.

Further, the first device described above may perform both signal processing of signals transmitted to and received from LoRa terminals and signal processing of signals transmitted to and received from Wi-SUN terminals. Alternatively, the first device that performs signal processing on signals sent to and received from the LoRa terminal and the first device that performs signal processing on signals sent to and received from the Wi-SUN terminal are provided separately. Good too.

<Terminal configuration>
FIG. 3 is a block diagram showing an example of the configuration of terminal 200 according to this embodiment. Terminal 200 includes a receiving section 201, a demodulating/decoding section 202, a controlling section 203, an encoding/modulating section 204, and a transmitting section 205.

Note that the terminal 200 that communicates with the base station 100 may be a LoRa terminal or a Wi-SUN terminal.

The receiving unit 201 receives a signal transmitted by the base station 100, and performs predetermined reception processing on the received signal. For example, the predetermined reception processing includes frequency conversion processing (downconversion) based on the frequency of a channel used for reception. Information on the frequency of the channel used for reception may be obtained from the control unit 203, for example.

Receiving section 201 outputs a received signal that has undergone predetermined reception processing to demodulating/decoding section 202 .

The demodulation/decoding section 202 performs demodulation processing and decoding processing on the received signal obtained from the receiving section 201, and generates received data or control information. Demodulation/decoding section 202 outputs received data or control information to control section 203. Note that the control information includes information regarding a channel assigned to terminal 200 and/or information regarding transmission power control for terminal 200. Further, when the terminal 200 is a LoRa terminal, the demodulation process may include despreading process for the spread spectrum used in the LoRa system.

The control unit 203 transfers the received data to an upper layer (not shown). Furthermore, control section 203 outputs transmission data transferred from the upper layer to encoding/modulation section 204.

Further, the control unit 203 sets a channel to be used for communication based on the control information, and outputs information on the frequency of the set channel to the transmitting unit 205 and/or the receiving unit 201. Further, the control unit 203 may perform transmission power control based on the control information.

Encoding/modulating section 204 performs encoding processing and modulation processing on the transmission data obtained from control section 203, and generates a transmission signal. Encoding/modulating section 204 outputs a transmission signal to transmitting section 205. Note that when the terminal 200 is a LoRa terminal, the modulation process may include spread spectrum processing used in the LoRa system.

Transmission section 205 performs predetermined transmission processing on the transmission signal obtained from encoding/modulation section 204. For example, the predetermined transmission processing includes frequency conversion processing (upconversion) based on the frequency of the channel assigned to terminal 200. Information on the frequency of the channel assigned to the terminal 200 may be obtained from the control unit 203, for example.

Furthermore, when the transmitting section 205 transmits a transmission signal, the control section 203 may perform transmission power control.

In the communication between the base station 100 and the terminal 200 described above, the base station 100 allocates a channel that the terminal 200 uses for communication (for example, transmitting a signal).

Base station 100 according to the present embodiment measures the interference of each channel and classifies the interference of each channel based on the interference measurement results. Base station 100 then assigns terminal 200 to a channel based on the classified interference. This allows the terminal 200 to transmit at the same time as the time when interference exists, thereby improving frequency usage efficiency.

Hereinafter, a plurality of variations will be exemplified with respect to an example of an interference classification result and an example of channel assignment based on the interference classification result.

<Variation 1>
In variation 1, the base station 100 classifies available channels into channels with a relatively large amount of interference or channels with a relatively small amount of interference based on the interference measurement results.

For example, the interference classification unit 105 monitors each channel for a predetermined period of time. The interference classification unit 105 determines that, as a result of monitoring, if the time during which interference (for example, interference power) exceeding a threshold value occurs is at least a certain percentage of a predetermined time, the channel in question is a channel with a relatively large amount of interference. I decide. Furthermore, as a result of monitoring, if the time during which interference (for example, interference power) occurring above a threshold value occurs is less than a certain percentage of the predetermined time, the base station 100 determines that the channel is a channel with a relatively small amount of interference. , it is decided.

FIG. 4 is a diagram showing an example of channel allocation in variation 1 of this embodiment. The horizontal axis in FIG. 4 indicates frequency, and the vertical axis indicates power or amount of interference. FIG. 4 shows channels f1 to f5 and the amount of interference of each channel. Note that although FIG. 4 shows an example in which the amounts of interference of channels f1 to f4 are equal to each other, the amounts of interference of channels f1 to f4 may be different from each other. Further, although FIG. 4 shows an example in which the amount of interference on channel f5 is zero, it is sufficient that the amount of interference on channel f5 is less than a predetermined value.

As shown in FIG. 4, in variation 1, the base station 100 assigns LoRa terminals to channels f1 to f4 with a relatively large amount of interference, and assigns Wi - SUN terminals may be assigned.

Further, as shown in FIG. 4, the base station 100 may instruct the LoRa terminals assigned to channels f1 to f4 to lower their transmission power. The instruction to lower the transmission power may be included in the information regarding transmission power control. Note that in FIG. 4, the transmission power (value on the vertical axis) of the terminals assigned to channels f1 to f5 is an example, and the transmission power of the terminal may be different from the example shown in FIG. 4. For example, the transmission powers of LoRa terminals assigned to channels f1 to f4 may be different from each other.

Note that the method of lowering the transmission power is not particularly limited. For example, a reference value of transmission power used in normal times (when transmission power control is not performed) is defined for a LoRa terminal. For example, when the LoRa terminal obtains an instruction to reduce the transmission power from the base station 100, the LoRa terminal may transmit a signal using the transmission power reduced by a predetermined percentage with respect to the reference value. Alternatively, the instruction to lower the transmission power may include a value of the transmission power (a value reduced from a reference value).

Next, the processing flow of the base station 100 in variation 1 will be described.

FIG. 5 is a flowchart illustrating an example of processing by base station 100 in variation 1 of the present embodiment. The process shown in FIG. 5 may be executed regularly or irregularly. Alternatively, it may be executed when a channel allocation request is received from the terminal 200.

The base station 100 measures the amount of interference for each channel (S101).

The base station 100 determines a channel with less interference (S102). There are no particular limitations on the method for determining channels with less interference. For example, when the (maximum or time average) amount of interference of channel fi (i is, for example, an integer of 1 or more) is less than or equal to a first threshold, channel fi may be determined to be a channel with little interference. Alternatively, if the interference occurrence time of channel fi per predetermined time is less than or equal to a predetermined ratio, channel fi may be determined to be a channel with less interference.

In other words, determining a channel with less interference corresponds to determining a channel to which a terminal can be assigned.

Note that the process of S102 may be omitted. If the process of S102 is omitted, the targets of the allocation process described below may be, for example, all available channels.

The base station 100 determines whether allocation processing for all of the determined channels has been completed (S103).

If the allocation process has not been completed (NO in S103), that is, if there is a channel (hereinafter referred to as "channel fx") for which the allocation process has not been completed among the channels determined in S102, The base station 100 executes the allocation process from S104 onwards for the channel fx. On the other hand, if the allocation process is completed (YES in S103), that is, if there is no channel (channel fx) for which the allocation process has not been completed among the channels determined in S102, the base station 100 performs the allocation process. End the processing flow of the process.

Base station 100 determines whether the amount of interference on channel fx is less than a predetermined value (S104). A channel in which the amount of interference is less than a predetermined value means an idle channel.

If the amount of interference on channel fx is less than the predetermined value (YES at S104), base station 100 determines to allocate a Wi-SUN terminal to channel fx (S105). Then, the process of S103 is executed.

If the amount of interference on channel fx is not less than the predetermined value (NO at S104), base station 100 determines to allocate a LoRa terminal to channel fx (S106).

Then, the base station 100 instructs the LoRa terminal assigned in S106 to lower its transmission power (S107). Then, the process of S103 is executed.

As described above, in variation 1 of the present embodiment, the base station 100 classifies channel interference based on whether the interference is relatively large or not, and determines to allocate a LoRa terminal to a channel where the interference is relatively large. . With this configuration, it is possible to allocate the terminal 200 even to a channel where interference is relatively large, thereby improving frequency usage efficiency.

Furthermore, in variation 1 of the present embodiment, base station 100 instructs LoRa terminals assigned to channels with relatively high interference to reduce transmission power. With this configuration, it is possible to suppress interference caused to other wireless communication devices that communicate on a channel where interference is relatively large. Furthermore, since the LoRa terminal performs spectrum spreading, a spreading gain can be obtained even when the transmission power is lowered. Therefore, the base station 100 can receive signals from the LoRa terminal even if the LoRa terminal lowers its transmission power.

<Variation 2>
Variation 1 shows an example in which the base station 100 classifies available channels into channels with a relatively large amount of interference or channels with a relatively small amount of interference. Variation 2 shows an example in which the base station 100 subdivides a channel with a relatively large amount of interference.

For example, the base station 100 determines the proportion of interference caused by signals transmitted by wireless communication devices included in the NW (Network) to which the base station 100 belongs, and the proportion of interference caused by signals transmitted by wireless communication devices included in the NW (Network) to which the base station 100 belongs, in the amount of interference for each channel. The proportion of interference caused by signals transmitted by wireless communication devices included in the wireless communication devices and signals transmitted by different wireless communication devices is determined.

The wireless communication device included in the NW to which the base station 100 belongs may be, for example, a wireless communication device (for example, a terminal) managed by the base station 100, or a wireless communication device under the control of the base station 100. It's good.

Note that, hereinafter, interference caused by a signal transmitted by a wireless communication device included in the NW to which the base station 100 belongs may be referred to as "intra-management interference."

A wireless communication device that is different from the wireless communication device included in the NW to which the base station 100 belongs is, for example, a wireless communication device that operates the same system as the base station 100 but belongs to a different NW than the base station 100, and a base station. 100 and a wireless communication device operated in a different system.

For example, in this embodiment, the system operated by base station 100 is LPWA. Therefore, a wireless communication device different from the wireless communication device included in the NW to which the base station 100 belongs is, for example, a NW that operates LPWA but is different from the base station 100 (for example, a NW of a different carrier than the base station 100). This includes wireless communication devices that belong to LPWA and wireless communication devices that operate in systems different from LPWA (for example, Wi-Fi, RFID).

Hereinafter, interference caused by a signal transmitted by a wireless communication device different from the wireless communication device included in the NW to which the base station 100 belongs may be referred to as "unmanaged interference."

That is, in variation 2, the base station 100 determines the ratio of managed interference to unmanaged interference in the amount of interference of each channel. The base station 100 then determines for each channel whether or not the channel is dominated by intra-management interference. Note that a channel in which managed interference is not dominant corresponds to a channel in which unmanaged interference is dominant.

The determination as to whether intra-management interference is predominant is determined based on, for example, whether the proportion of intra-management interference is equal to or higher than a predetermined proportion.

In the following, a channel in which managed interference is dominant may be referred to as a "managed interference channel." Furthermore, a channel in which unmanaged interference is dominant may be described as an "unmanaged interference channel."

In variation 2, the base station 100 classifies channels with a relatively large amount of interference into managed interference channels and unmanaged interference channels. The base station 100 then assigns the LoRa terminal to the unmanaged interference channel.

FIG. 6 is a diagram showing an example of interference classification in variation 2 of this embodiment. The horizontal axis in FIG. 6 indicates frequency, and the vertical axis indicates power or amount of interference. FIG. 6 shows channels f1 to f5 and the amount of interference of each channel.

FIG. 6 shows that channel f1 and channel f2 are unmanaged interference channels, channel f3 and channel f4 are managed interference channels, and channel f5 is an empty channel. . Note that although FIG. 6 shows an example in which the amounts of interference of channels f1 to f4 are equal to each other, channels f1 to f4 may have different amounts of interference. Further, although FIG. 6 shows an example in which the amount of interference on channel f5 is zero, if the amount of interference on channel f5 is less than a predetermined value, channel f5 may be determined to be an empty channel.

FIG. 7 is a diagram showing an example of channel allocation in variation 2 of this embodiment. The example shown in FIG. 7 is an example of channel assignment for the interference classification results shown in FIG. 6.

As shown in FIG. 7, in variation 2, the base station 100 may allocate LoRa terminals to unmanaged interference channels f1 and f2, and may allocate a Wi-SUN terminal to vacant channel f5.

Further, as shown in FIG. 7, the base station 100 may instruct the LoRa terminals assigned to channels f1 to f2 to lower their transmission power. The instruction to lower the transmission power may be included in the information regarding transmission power control. Note that the method for lowering the transmission power is the same as in variation 1, so a description thereof will be omitted. Note that in FIG. 7, the transmission power (value on the vertical axis) of the terminals assigned to channels f1, f2, and f5 is an example, and the transmission power of the terminal may be different from the example shown in FIG. good. For example, the transmission powers of LoRa terminals assigned to channels f1 and f2 may be different from each other.

Next, the processing flow of the base station 100 in variation 2 will be described.

FIG. 8 is a flowchart illustrating an example of processing by base station 100 in variation 2 of this embodiment. Note that in FIG. 8, processes similar to those in FIG. 5 are given the same reference numerals, and descriptions thereof will be omitted as appropriate.

After determining a channel with less interference in S102, the base station 100 classifies channel interference (S201). For example, in variation 2, the base station 100 classifies channel interference based on whether unmanaged interference is dominant.

The base station 100 determines whether the allocation process for all the channels determined in S102 has been completed (S103).

If the allocation process has not been completed (NO in S103), that is, if there is a channel (hereinafter referred to as "channel fx") for which the allocation process has not been completed among the channels determined in S102, The base station 100 executes the allocation process from S104 onwards for the channel fx.

Base station 100 determines whether the amount of interference on channel fx is less than a predetermined value (S104). A channel in which the amount of interference is less than a predetermined value means an idle channel.

If the amount of interference on channel fx is less than the predetermined value (YES at S104), base station 100 determines to allocate a Wi-SUN terminal to channel fx (S105). Then, the process of S103 is executed.

If the amount of interference on channel fx is not less than the predetermined value (NO at S104), base station 100 determines whether channel fx is an unmanaged interference channel (S202).

If channel fx is an unmanaged interference channel (YES in S202), base station 100 determines to allocate a LoRa terminal to channel fx (S203).

Then, the base station 100 instructs the LoRa terminal assigned in S203 to lower the transmission power (S204). Then, the process of S103 is executed.

If channel fx is not an unmanaged interference channel (NO in S202), base station 100 does not need to allocate channel fx. Then, the process of S103 is executed.

As described above, in variation 2 of the present embodiment, base station 100 classifies channel interference based on whether or not the interference is relatively large, and determines whether the channel with relatively large interference is an unmanaged interference channel. Determine whether or not. Then, the base station 100 decides to allocate the LoRa terminal to the unmanaged interference channel. With this configuration, it is possible to allocate LoRa terminals even to unmanaged interference channels where interference is relatively large, thereby improving frequency usage efficiency. Further, since no terminal is assigned to the managed interference channel, interference with the NW to which the base station 100 belongs can be suppressed.

Furthermore, in variation 2 of the present embodiment, base station 100 instructs LoRa terminals assigned to unmanaged interference channels to lower their transmission power. With this configuration, it is possible to suppress interference to a wireless communication device that causes unmanaged interference. Furthermore, since the LoRa terminal performs spectrum spreading, a spreading gain can be obtained even when the transmission power is lowered. Therefore, the base station 100 can receive signals from the LoRa terminal even if the LoRa terminal lowers its transmission power.

<Variation 3>
In variation 3, an example will be described in which the base station classifies channels with a relatively large amount of interference into managed interference channels and unmanaged interference channels, and assigns LoRa terminals to the managed interference channels.

Note that the classification of unmanaged interference channels and managed interference channels is the same as in variation 2, and is illustrated in FIG. 6, for example, so a description thereof will be omitted.

FIG. 9 is a diagram showing an example of channel allocation in variation 3 of this embodiment. The example shown in FIG. 9 is an example of channel assignment for the interference classification results shown in FIG. 6.

As shown in FIG. 9, in variation 3, the base station 100 may allocate LoRa terminals to managed interference channels f3 and f4, and may allocate a Wi-SUN terminal to vacant channel f5.

Further, as shown in FIG. 9, the base station 100 may instruct the LoRa terminals assigned to channels f3 to f4 to lower their transmission power. The instruction to lower the transmission power may be included in the information regarding transmission power control. Note that the method for lowering the transmission power is the same as in variation 1, so a description thereof will be omitted. Note that in FIG. 9, the transmission power (value on the vertical axis) of the terminals assigned to channels f3, f4, and f5 is an example, and the transmission power of the terminal may be different from the example shown in FIG. good. For example, the transmission powers of LoRa terminals assigned to channels f3 and f4 may be different from each other.

Next, the processing flow of the base station 100 in variation 3 will be described.

FIG. 10 is a flowchart illustrating an example of processing by base station 100 in variation 3 of this embodiment. Note that in FIG. 10, processes similar to those in FIGS. 5 and 8 are given the same reference numerals, and descriptions thereof will be omitted as appropriate.

If the amount of interference of the channel fx for which the allocation process has not been completed is not less than the predetermined value (NO in S104), the base station 100 determines whether the channel fx is an unmanaged interference channel (S301).

If channel fx is not an unmanaged interference channel (NO in S301), that is, if channel fx is a managed interference channel, base station 100 determines to allocate a LoRa terminal to channel fx (S302).

Then, the base station 100 instructs the LoRa terminal assigned in S302 to lower the transmission power (S303). Then, the process of S103 is executed.

If channel fx is an unmanaged interference channel (YES in S301), base station 100 does not need to allocate channel fx. Then, the process of S103 is executed.

As described above, in variation 3 of the present embodiment, base station 100 classifies channel interference based on whether or not the interference is relatively large, and determines whether the channel with relatively large interference is an unmanaged interference channel. Determine whether or not. Then, the base station 100 determines to allocate the LoRa terminal to a channel that is not an unmanaged interference channel, that is, a managed interference channel. With this configuration, it is possible to allocate the terminal 200 even to a managed interference channel where the interference is relatively large, so that frequency usage efficiency can be improved. Furthermore, since the configuration is such that interference is controlled within the NW to which the base station 100 belongs, interference with wireless communication devices that are not included in the NW to which the base station 100 belongs can be suppressed.

Furthermore, in variation 3 of the present embodiment, the base station 100 instructs the LoRa terminal assigned to the managed interference channel to lower the transmission power. With this configuration, it is possible to suppress interference to a wireless communication device that causes intra-management interference. Furthermore, since the LoRa terminal performs spectrum spreading, a spreading gain can be obtained even when the transmission power is lowered. Therefore, the base station 100 can receive signals from the LoRa terminal even if the LoRa terminal lowers its transmission power.

<Variation 4>
In variation 4, an example will be described in which the base station 100 subdivides the unmanaged interference channel.

For example, in each unmanaged interference channel, the base station 100 operates on the same system as the base station 100, but is caused by a signal transmitted by a wireless communication device belonging to a different NW than the base station 100. Determine the percentage of interference.

Note that in the following, interference caused by a signal transmitted by a wireless communication device that operates the same system as the base station 100 but whose NW is different from the base station 100 may be described as "radio wave interference." . Furthermore, interference that is included in unmanaged interference and is different from "radio wave interference" is sometimes described as "environmental noise."

Environmental noise includes, for example, interference caused by signals transmitted by wireless communication devices operating in a system different from base station 100. For example, environmental noise includes interference caused by Wi-Fi wireless communication devices, RFID, and signals transmitted by wireless communication devices using adjacent channels such as LTE.

That is, the base station 100 determines the ratio of radio wave interference to environmental noise in the amount of interference of each unmanaged interference channel. Then, the base station 100 determines whether radio wave interference is dominant for each of the unmanaged channels. Note that an unmanaged interference channel in which radio wave interference is not dominant corresponds to an unmanaged interference channel in which environmental noise is dominant.

Note that the radio wave interference included in the unmanaged interference is caused by, for example, a signal transmitted by a LoRa terminal and/or a Wi-SUN terminal that is not included in the NW to which the base station 100 belongs. As described above, the preamble detection unit 104 of the base station 100 can determine the type of preamble included in the signal transmitted by the LoRa terminal and Wi-SUN terminal that are not included in the NW to which the base station 100 belongs. Therefore, the base station 100 can determine the proportion of radio wave interference included in unmanaged interference and classify the interference.

The determination as to whether radio wave interference is dominant is made, for example, based on whether the ratio of radio wave interference is greater than or equal to a predetermined ratio.

FIG. 11 is a diagram showing an example of interference classification in variation 4 of this embodiment. The horizontal axis in FIG. 11 indicates frequency, and the vertical axis indicates power or interference amount. FIG. 11 shows channels f1 to f4 and the amount of interference of each channel.

In FIG. 11, channels f1 to f4 are unmanaged interference channels, and the ratio of radio wave interference to environmental noise in each channel is shown. Note that although FIG. 11 shows an example in which the total amount of interference, which is the sum of radio wave interference and environmental noise for channels f1 to f4, is equal to each other, the total amount of interference for channels f1 to f4 is different from each other. good.

FIG. 12 is a diagram showing an example of channel allocation in variation 4 of this embodiment. The example shown in FIG. 12 is an example of channel assignment for the interference classification results shown in FIG. 11.

As shown in FIG. 12, in variation 4, the base station 100 may assign the Wi-SUN terminal to the channel f2 in which environmental noise is dominant among the unmanaged interference channels f1 to f4. Although not shown, in variation 4, the base station 100 may allocate a LoRa terminal to a channel in which radio wave interference is dominant (for example, channel f4 in FIG. 12) among unmanaged interference channels f1 to f4. .

Furthermore, as shown in FIG. 12, the base station 100 may instruct the Wi-SUN terminal assigned to channel f2 to increase its transmission power. The instruction to increase the transmission power may be included in the information regarding transmission power control. Note that in FIG. 12, the transmission power (value on the vertical axis) of the terminal assigned to channel f2 is an example, and the transmission power of the terminal may be different from the example shown in FIG. 12.

Note that the method of increasing the transmission power is not particularly limited. For example, for a Wi-SUN terminal, a reference value of transmission power used in normal times (when transmission power control is not performed) is defined. For example, when the Wi-SUN terminal receives an instruction to increase the transmission power from the base station 100, it may transmit a signal using the transmission power increased by a predetermined percentage with respect to the reference value. Alternatively, the instruction to increase the transmission power may include a value of the transmission power (a value increased from a reference value).

Next, the processing flow of the base station 100 in variation 4 will be described.

FIG. 13 is a flowchart illustrating an example of processing by base station 100 in variation 4 of this embodiment. Note that in FIG. 13, processes similar to those in FIGS. 5, 8, and 10 are given the same reference numerals, and descriptions thereof will be omitted as appropriate.

If the amount of interference of the channel fx for which the allocation process has not been completed is not less than the predetermined value (NO in S104), the base station 100 determines whether the channel fx is an unmanaged interference channel (S202).

If channel fx is not an unmanaged interference channel (NO in S202), base station 100 does not need to allocate channel fx. Then, the process of S103 is executed.

If the channel fx is an unmanaged interference channel (YES in S202), the base station 100 determines whether radio wave interference is dominant in the interference of the channel fx (S401).

When radio wave interference is dominant in the interference of channel fx (YES in S401), the base station 100 determines to allocate a LoRa terminal to channel fx (S402).

Then, the base station 100 instructs the LoRa terminal assigned in S402 to lower the transmission power (S403). Then, the process of S103 is executed.

In the interference of channel fx, if radio wave interference is not dominant (NO in S401), for example, if environmental noise is dominant, the base station 100 determines to allocate the Wi-SUN terminal to channel fx. (S404).

Then, the base station 100 instructs the Wi-SUN terminal assigned in S404 to increase the transmission power (S405). Then, the process of S103 is executed.

As described above, in variation 4 of the present embodiment, the base station 100 determines whether radio wave interference is dominant in the unmanaged interference channel. Then, among the unmanaged interference channels, the base station 100 allocates the Wi-SUN terminal to a channel in which radio wave interference is not dominant (for example, a channel in which environmental noise is dominant), and assigns the Wi-SUN terminal to a channel in which radio wave interference is dominant. Decide to allocate. With this configuration, it is possible to allocate LoRa terminals and/or Wi-SUN terminals even to unmanaged interference channels where interference is relatively large, so that frequency usage efficiency can be improved. Furthermore, interference with the NW to which the base station 100 belongs can be suppressed.

Furthermore, in variation 4 of the present embodiment, base station 100 instructs Wi-SUN terminals assigned to channels where radio wave interference is not dominant to increase transmission power. With this configuration, Wi-SUN terminals can transmit transmission signals while suppressing interference with other terminals (for example, terminals in the same NW as base station 100), improving the quality of the transmission signals of Wi-SUN terminals. can.

Note that although the above-mentioned variation 4 describes an example in which a Wi-SUN terminal is assigned to an unmanaged interference channel in which environmental noise is dominant, the present disclosure is not limited to this. For example, a LoRa terminal may be assigned to an unmanaged interference channel where environmental noise is dominant. Further, in that case, an instruction may be given to the LoRa terminal to increase the transmission power.

For example, when a LoRa terminal is assigned to an unmanaged interference channel (variation 2 described above), the LoRa terminal may be assigned with priority over an unmanaged interference channel in which environmental noise is dominant.

Furthermore, in a channel where unmanaged interference is dominant, a method of detecting a known signal such as a preamble is described as a method of identifying whether radio wave interference or environmental noise is dominant. Other methods may be used. For example, the base station 100 may estimate the frequency band of the signal causing interference by performing Fourier transform or the like on the received signal in each channel. Then, the base station 100 determines whether, in the estimated frequency band, the frequency band of the wireless communication system that corresponds to radio wave interference is dominant, or the frequency band of the wireless communication system that corresponds to environmental noise is dominant. By determining , it may be possible to identify whether radio wave interference or environmental noise is dominant. As mentioned above, wireless communication systems that fall under radio wave interference are, for example, the LoRa system and/or Wi-SUN system, and wireless communication systems that fall under environmental noise are, for example, Wi-fi, RFID, and adjacent channels such as LTE.

Here, in the above-mentioned variation 4, it is assumed that the wireless communication system corresponding to the environmental noise performs communication with a low priority. When the communication priority of the wireless communication system corresponding to the environmental noise is high, the base station 100 selects a channel for the wireless communication system corresponding to the environmental noise to satisfy a predetermined communication quality in a channel where the environmental noise is dominant. Assignments may be made. In this case, for example, the base station 100 may assign the LoRa terminal to a channel where environmental noise is dominant, similar to the channel where unmanaged interference is dominant, and set the transmission power of the LoRa terminal low. Through such allocation, it is possible to improve the frequency usage efficiency while satisfying the communication quality of the wireless communication system corresponding to environmental noise.

<Variation 5>
Variation 5 is an example in which the base station 100 subdivides the unmanaged interference channel, and an example different from variation 4 will be described.

For example, the base station 100 determines the rate of interference caused by signals transmitted by Wi-SUN terminals (hereinafter sometimes referred to as "Wi-SUN interference") in each unmanaged interference channel, and the rate of interference caused by signals transmitted by Wi-SUN terminals and the rate of interference caused by signals transmitted by Wi-SUN terminals. determining the percentage of interference caused by the transmitted signal; In the following, interference caused by signals transmitted by Wi-SUN terminals may be described as "Wi-SUN interference", and interference caused by signals transmitted by LoRa terminals may be described as "LoRa interference". .

Here, the Wi-SUN terminal to be determined may be a Wi-SUN terminal included in the same NW as the base station 100, or a Wi-SUN terminal included in a different NW from the base station 100. or both. Further, the LoRa terminal to be determined may be a LoRa terminal included in the same NW as the base station 100, a LoRa terminal included in a different NW from the base station 100, or a LoRa terminal included in the same NW as the base station 100, It may be both.

Note that, as described above, the preamble detection unit 104 of the base station 100 can determine the type of preamble included in the signal transmitted by the LoRa terminal and Wi-SUN terminal that are not included in the NW to which the base station 100 belongs. Therefore, the base station 100 can determine the proportion of Wi-SUN interference included in unmanaged interference and the proportion of LoRa interference included in unmanaged interference, and classify the interference.

The base station 100 assigns LoRa terminals to channels where Wi-SUN interference is dominant.

FIG. 14 is a diagram showing an example of interference classification in variation 5 of this embodiment. The horizontal axis in FIG. 14 indicates frequency, and the vertical axis indicates power or interference amount. FIG. 14 shows channels f1 to f5 and the amount of interference of each channel.

FIG. 14 shows that channel f1 and channel f2 are unmanaged interference channels, channel f3 and channel f4 are managed interference channels, and channel f5 is an empty channel. . Further, in FIG. 14, channel f1 is a channel where Wi-SUN interference is dominant, and channel f2 is a channel where LoRa interference is dominant. Note that although FIG. 14 shows an example in which the amounts of interference of channels f1 to f4 are equal to each other, the amounts of interference of channels f1 to f4 may be different from each other. Further, although FIG. 14 shows an example in which the amount of interference on channel f5 is zero, if the amount of interference on channel f5 is less than a predetermined value, channel f5 may be determined to be an empty channel.

FIG. 15 is a diagram showing an example of channel allocation in variation 5 of this embodiment. The example shown in FIG. 15 is an example of channel assignment for the interference classification results shown in FIG. 14.

As shown in FIG. 15, in variation 5, the base station 100 may assign the LoRa terminal to the channel f1 in which Wi-SUN interference is dominant among the unmanaged interference channels f1 and f2. Furthermore, the base station 100 may allocate a Wi-SUN terminal to the vacant channel f5.

Further, as shown in FIG. 15, the base station 100 instructs the LoRa terminal assigned to the channel f1 to lower the transmission power. The instruction to lower the transmission power may be included in the information regarding transmission power control. Note that the method for lowering the transmission power is the same as in variation 1, so a description thereof will be omitted. Note that in FIG. 15, the transmission power (value on the vertical axis) of the terminals assigned to channels f1 and f5 is an example, and the transmission power of the terminal may be different from the example shown in FIG. 15.

Next, the processing flow of the base station 100 in variation 5 will be described.

FIG. 16 is a flowchart illustrating an example of processing by base station 100 in variation 5 of this embodiment. Note that in FIG. 16, processes similar to those in FIGS. 5, 8, 10, etc. are given the same reference numerals, and descriptions thereof will be omitted as appropriate.

If the amount of interference of the channel fx for which the allocation process has not been completed is not less than the predetermined value (NO in S104), the base station 100 determines whether the channel fx is an unmanaged interference channel (S202).

If channel fx is not an unmanaged interference channel (NO in S202), base station 100 does not need to allocate channel fx. Then, the process of S103 is executed.

If channel fx is an unmanaged interference channel (YES in S202), base station 100 determines whether Wi-SUN interference is dominant in the interference of channel fx (S501).

When Wi-SUN interference is dominant in the interference on channel fx (YES at S501), the base station 100 determines to allocate a LoRa terminal to channel fx (S502).

Then, the base station 100 instructs the LoRa terminal assigned in S502 to lower the transmission power (S503). Then, the process of S103 is executed.

In the interference of channel fx, if Wi-SUN interference is not dominant (NO in S501), for example, if LoRa interference is dominant, the base station 100 does not assign the terminal to channel fx and performs the process in S103. Processing is executed.

As described above, in variation 5 of the present embodiment, the base station 100 determines whether radio wave interference is dominant in the unmanaged interference channel. Then, the base station 100 determines to allocate the LoRa terminal to a channel in which Wi-SUN interference is dominant among the unmanaged interference channels. In this configuration, by assigning LoRa terminals whose spreading gain decreases when the spreading factor is small or the orthogonality between spreading codes is low, to a channel where Wi-SUN interference is dominant, the interference is relatively large. Since LoRa terminals can be assigned to external interference channels, frequency usage efficiency can be improved. Furthermore, interference with the NW to which the base station 100 belongs can be suppressed. Furthermore, communication quality can be ensured in LoRa terminals where spreading gain decreases.

Furthermore, in variation 5 of the present embodiment, the base station 100 instructs the assigned LoRa terminal to lower the transmission power. With this configuration, it is possible to suppress interference to a wireless communication device that causes unmanaged interference. Furthermore, since the LoRa terminal performs spectrum spreading, a spreading gain can be obtained even when the transmission power is lowered. Therefore, the base station 100 can receive signals from the LoRa terminal even if the LoRa terminal lowers its transmission power.

Furthermore, in variation 5 of the present embodiment, the base station 100 suppresses a decrease in the spreading gain of the spread spectrum used by the LoRa terminal by assigning the LoRa terminal to a channel where Wi-SUN interference is dominant, and It is possible to prevent deterioration of the communication quality of the terminal.

For example, LoRa terminals perform spectrum spreading using spreading codes, so in channels where LoRa interference is dominant, the orthogonality between spreading codes may decrease, leading to a decrease in spreading gain. . In variation 5 of the present embodiment, since LoRa terminals are assigned to channels where Wi-SUN interference is dominant, the orthogonality between spreading codes does not deteriorate. Therefore, it is possible to suppress a decrease in the spreading gain of the LoRa terminal.

Note that in variation 5 described above, an example was explained in which a LoRa terminal is assigned to a channel in which Wi-SUN interference is dominant among unmanaged interference channels, but the present disclosure is not limited to this. For example, a LoRa terminal may be assigned to a channel in which Wi-SUN interference is dominant among managed interference channels. Even with such a configuration, it is possible to suppress a decrease in the spreading gain of the spread spectrum used by the LoRa terminal, and to prevent deterioration of the communication quality of the LoRa terminal.

Furthermore, in variation 5 described above, a Wi-SUN terminal may be assigned to a channel in which LoRa interference is dominant among unmanaged interference channels. In this case, the base station 100 instructs the assigned Wi-SUN terminal to increase its transmission power.

Here, the LoRa terminal to be determined whether LoRa interference is dominant may be a LoRa terminal included in the same NW as the base station 100, or a LoRa terminal included in the same NW as the base station 100. It may be a terminal or both. Further, the Wi-SUN terminal to be determined may be a Wi-SUN terminal included in the same NW as the base station 100, or a Wi-SUN terminal included in a different NW from the base station 100. or both.

However, the spreading factor of LoRa terminals in the NW to which the base station 100 does not belong is not known at the base station 100, and the spreading factor may be low. Furthermore, it is also possible that the spreading factor of LoRa terminals in the NW to which the base station 100 belongs is low. In such a case, the base station 100 may allocate Wi-SUN terminals only to channels where intra-management interference is dominant and where LoRa terminals with a large spreading factor are dominant.

Furthermore, in variation 5 described above, the base station 100 transmits a signal to a channel in which LoRa interference is dominant that has a spreading factor different from that of a signal transmitted by a LoRa terminal on the channel (hereinafter sometimes referred to as "LoRa signal"). LoRa terminals may be assigned using a spreading factor. This is because, in general, there is a high possibility that interference between LoRa signals having different spreading factors can be reduced by using spreading gain. In this case, because of interference between LoRa signals, the base station 100 does not need to instruct the assigned LoRa terminal to increase its transmission power. However, when assigning a LoRa terminal with a smaller spreading factor than the LoRa signal in the channel to a channel where LoRa interference with a large spreading factor is dominant, the base station 100 instructs the assigned LoRa terminal to increase its transmission power. It's okay.

In this case as well, the LoRa terminal to be determined whether LoRa interference is dominant may be a LoRa terminal included in the same NW as the base station 100, or a LoRa terminal included in a different NW than the base station 100. It may be a LoRa terminal or both.

However, although the base station 100 knows the spreading factors of LoRa terminals included in the same NW as the base station 100, the spreading factors of LoRa terminals included in a different NW from the base station 100 are not known. Therefore, the base station 100 may perform a process of detecting the spreading factor of the received LoRa signal. Alternatively, the base station 100 may use a LoRa terminal included in the same NW as the base station 100 to determine whether LoRa interference is dominant. In this way, by limiting the targets of determination, it is possible to eliminate the need for detection processing of the spreading factor of the received LoRa signal.

<Variation 6: About device classification>
In variations 1 to 5 described above, the base station 100 classifies channel interference and, depending on the result of the channel interference classification, assigns a channel to a Wi-SUN terminal and/or a channel to assign a LoRa terminal. An example of how to make a decision has been explained. The classification of terminals in the present disclosure is not limited to the two classifications of Wi-SUN terminals and LoRa terminals.

For example, the base station 100 may classify the terminals 200 based on parameters related to communication quality between the terminals 200 and the base station 100.

For example, the parameter related to the communication quality between the terminal 200 and the base station 100 may be a parameter related to the distance between the terminal 200 and the base station 100. The parameter related to the distance between terminal 200 and base station 100 may be, for example, the reception strength of the signal that base station 100 receives from terminal 200 (for example, Received Signal Strength Indicator (RSSI)).

For example, the base station 100 may classify LoRa terminals into LoRa terminals with relatively good communication quality and LoRa terminals with relatively poor communication quality based on communication quality. Channels with different interference classifications may be assigned to a LoRa terminal with relatively good communication quality and a LoRa terminal with relatively poor communication quality.

Note that the method of classifying LoRa terminals with relatively good communication quality and LoRa terminals with relatively poor communication quality is not limited. For example, among the RSSIs of each LoRa terminal, LoRa terminals with RSSI equal to or higher than a threshold are classified as LoRa terminals with relatively good communication quality, and LoRa terminals with RSSI below the threshold are classified as LoRa terminals with relatively poor communication quality. It may be classified as a terminal.

Below, as an example of variation 6, an example of changing the terminal classification in variation 2 will be described.

FIG. 17 is a diagram showing an example of channel allocation in which the classification of terminals is changed in variation 2 of the present embodiment. The example shown in FIG. 17 is an example of channel assignment for the interference classification results shown in FIG. 6.

As shown in FIG. 17, the base station 100 may allocate LoRa terminals with good communication quality to unmanaged interference channels f1 and f2, and allocate Wi-SUN terminals and LoRa terminals with poor communication quality to vacant channel f5.

Further, as shown in FIG. 17, the base station 100 instructs LoRa terminals with good communication quality assigned to channels f1 to f2 to lower their transmission power. The instruction to lower the transmission power may be included in the information regarding transmission power control. Note that the method for lowering the transmission power is the same as in variation 1, so a description thereof will be omitted.

Next, in variation 2, a processing flow of base station 100 in an example of changing the classification of a terminal will be described.

FIG. 18 is a flowchart illustrating an example of processing by base station 100 when changing the classification of a terminal in variation 2 of the present embodiment. Note that in FIG. 18, processes similar to those in FIGS. 5, 8, 10, etc. are given the same reference numerals, and descriptions thereof will be omitted as appropriate.

After classifying channel interference in S201, the base station 100 classifies terminals based on communication quality (S601).

The base station 100 determines whether the allocation process for all the channels determined in S102 has been completed (S602).

If the allocation process has not been completed (NO in S602), that is, if there is a channel (hereinafter referred to as "channel fx") for which the allocation process has not been completed among the channels determined in S102, The base station 100 executes the allocation process from S603 onwards for the channel fx. On the other hand, if the allocation process is completed (YES in S602), that is, if there is no channel (channel fx) for which the allocation process has not been completed among the channels determined in S102, the base station 100 performs the allocation process. End the processing flow of the process.

The base station 100 determines whether the amount of interference on channel fx is less than a predetermined value (S603). A channel in which the amount of interference is less than a predetermined value means an idle channel.

If the amount of interference on channel fx is less than the predetermined value (YES in S603), base station 100 determines to allocate Wi-SUN terminals and LoRa terminals with poor communication quality to channel fx (S604). Then, the process of S602 is executed.

If the amount of interference of channel fx is not less than the predetermined value (NO in S603), base station 100 determines whether channel fx is an unmanaged interference channel (S605).

If channel fx is not an unmanaged interference channel (NO in S605), base station 100 does not need to allocate channel fx. Then, the process of S602 is executed.

If the channel fx is an unmanaged interference channel (YES in S605), the base station 100 determines to allocate a LoRa terminal with good communication quality to the channel fx (S606).

Then, the base station 100 instructs the LoRa terminal assigned in S606 to lower the transmission power (S607). Then, the process of S602 is executed.

As described above, in variation 6 of the present embodiment, base station 100 classifies channel interference based on whether or not the interference is relatively large, and determines whether the channel with relatively large interference is an unmanaged interference channel. Determine whether or not. Then, the base station 100 determines to allocate a LoRa terminal with good communication quality to the unmanaged interference channel. With this configuration, it is possible to allocate the terminal 200 to an unmanaged interference channel where the interference is relatively large, thereby improving frequency usage efficiency and suppressing interference with the NW to which the base station 100 belongs.

Furthermore, in variation 6 of the present embodiment, the base station 100 allocates a LoRa terminal with good communication quality to an unmanaged interference channel, and allocates a LoRa terminal with poor communication quality to an empty channel. With this configuration, it is possible to avoid a situation where a LoRa terminal with poor communication quality is assigned to an unmanaged interference channel, resulting in deterioration of communication with the base station 100.

Furthermore, in variation 6 of the present embodiment, base station 100 instructs LoRa terminals with good communication quality, which are assigned to unmanaged interference channels, to lower their transmission power. With this configuration, it is possible to suppress interference to a wireless communication device that causes unmanaged interference. Furthermore, since the LoRa terminal performs spectrum spreading, a spreading gain can be obtained even when the transmission power is lowered. Therefore, the base station 100 can receive signals from the LoRa terminal even if the LoRa terminal lowers its transmission power.

Note that although variation 6 described above shows an example in which terminals are classified based on communication quality and channel allocation is changed, the present disclosure is not limited to this. For example, terminals may be classified based on information transmitted by terminal 200, and channel assignment may be changed.

For example, the base station 100 may assign LoRa terminals that transmit relatively important information to vacant channels, and assign LoRa terminals that transmit relatively unimportant information to unmanaged interference channels. With this configuration, communication quality can be ensured when relatively important information is transmitted. Note that the relatively important information is, for example, retransmission information or control information.

Further, in variation 6 described above, an example was explained in which the classification of the terminal is changed in variation 2. This disclosure is not limited thereto. For example, the classification of the terminal may be changed even in variations different from variation 2 (eg, variations 1, 3 to 5).

For example, when changing the classification of terminals in variation 3, the base station 100 may assign LoRa terminals with good communication quality to the managed interference channel. Further, in this case, an instruction may be given to the LoRa terminal to lower the transmission power.

Furthermore, for example, when changing the terminal classification in variation 4, the base station 100 may assign a LoRa terminal with poor communication quality to a channel in which environmental noise is dominant among unmanaged interference channels. Further, an instruction may be given to the LoRa terminal in this case to increase the transmission power.

Furthermore, for example, when changing the classification of terminals in variation 5, the base station 100 may assign LoRa terminals with good communication quality to channels in which Wi-SUN interference is dominant among unmanaged interference channels. . Further, an instruction may be given to the LoRa terminal in this case to lower the transmission power.

In addition, the notation "... section" in the above embodiments refers to "... circuit", "... device", "... unit", or "... module". Other notations may be substituted.

In addition, the expression "channel" in the above embodiments may refer to other words such as "frequency," "frequency channel," "band," "band," "carrier," "subcarrier," or "(frequency) resource." may be replaced with the notation.

The present disclosure can be implemented with software, hardware, or software in conjunction with hardware.

Each functional block used in the description of the above embodiment is partially or entirely realized as an LSI that is an integrated circuit, and each process explained in the above embodiment is partially or entirely realized as an LSI, which is an integrated circuit. It may be controlled by one LSI or a combination of LSIs. An LSI may be composed of individual chips, or may be composed of a single chip that includes some or all of the functional blocks. The LSI may include data input and output. LSIs are sometimes called ICs, system LSIs, super LSIs, and ultra LSIs depending on the degree of integration.

The method of circuit integration is not limited to LSI, but may be implemented using a dedicated circuit, a general-purpose processor, or a dedicated processor. Furthermore, an FPGA (Field Programmable Gate Array) that can be programmed after the LSI is manufactured or a reconfigurable processor that can reconfigure the connections and settings of circuit cells inside the LSI may be used. The present disclosure may be implemented as digital or analog processing.

Furthermore, if an integrated circuit technology that replaces LSI emerges due to advancements in semiconductor technology or other derived technology, then of course the functional blocks may be integrated using that technology. Possibilities include the application of biotechnology.

The present disclosure can be implemented in all types of devices, devices, and systems (collectively referred to as communication devices) that have communication capabilities. Non-limiting examples of communication devices include telephones (mobile phones, smart phones, etc.), tablets, personal computers (PCs) (laptops, desktops, notebooks, etc.), cameras (digital still/video cameras, etc.) ), digital players (e.g. digital audio/video players), wearable devices (e.g. wearable cameras, smartwatches, tracking devices), game consoles, digital book readers, telehealth/telemedicine (e.g. These include care/medicine prescription) devices, communication-enabled vehicles or mobile transportation (cars, airplanes, ships, etc.), and combinations of the various devices described above.

Communication equipment is not limited to portable or movable, but also non-portable or fixed equipment, devices, systems, such as smart home devices (home appliances, lighting equipment, smart meters or It also includes measuring devices, control panels, etc.), vending machines, and any other "things" that can exist on an Internet of Things (IoT) network.

Communication includes data communication using cellular systems, wireless LAN systems, communication satellite systems, etc., as well as data communication using a combination of these.

Communication apparatus also includes devices such as controllers and sensors that are connected or coupled to communication devices that perform the communication functions described in this disclosure. Examples include controllers and sensors that generate control and data signals used by communication devices to perform communication functions of a communication device.

Communication equipment also includes infrastructure equipment, such as base stations, access points, and any other equipment, devices, or systems that communicate with or control the various equipment described above, without limitation. .

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 those skilled in the art can come up with various changes or modifications within the scope of the claims, and these naturally fall within the technical scope of the present disclosure. Understood. Further, each of the constituent elements in the above embodiments may be arbitrarily combined without departing from the spirit of the disclosure.

Although specific examples of the present disclosure have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes to the specific examples illustrated above.

The present disclosure is suitable for wireless communication systems.

100 base station 101, 201 receiving section 102, 202 demodulation/decoding section 103 communication quality measurement section 104 preamble detection section 105 interference classification section 106 allocation control section 107 control signal generation section 108, 204 encoding/modulation section 109, 205 transmission section 200 terminal 203 control unit

Claims (11)

a classification unit that determines a group of first channels in which the amount of interference is greater than a first threshold;
a control unit that assigns a first terminal using a spread spectrum method to a second channel included in the first channel group;
Equipped with
The control unit assigns a second terminal different from the first terminal to a channel different from the first channel,
The second terminal is a terminal that performs communication without using a spread spectrum method,
base station. the control unit instructs the first terminal assigned to the second channel to reduce transmission power;
The base station according to claim 1. The classification unit determines, among the first channel group, the second channel that includes interference from a wireless device existing in the same network as the base station at a predetermined rate or more.
The base station according to claim 1. The classification unit determines, among the first channel group, the second channel that includes interference from a wireless device different from a wireless device existing in the same network as the base station at a predetermined rate or more.
The base station according to claim 1. A base station,
a classification unit that determines a group of first channels in which the amount of interference is greater than a first threshold;
a control unit that assigns a first terminal using a spread spectrum method to a second channel included in the first channel group;
Equipped with
The classification unit determines, among the first channel group, a third channel group that includes interference from a wireless device different from a wireless device existing in the same network as the base station at a predetermined rate or more;
The control unit includes:
A second terminal different from the first terminal is connected to the third channel in the third channel group, which includes interference from a wireless device corresponding to a system different from the base station at a predetermined rate or more. assign,
base station. the control unit instructs the second terminal assigned to the third channel to increase transmission power;
The base station according to claim 5. The second terminal is a terminal that performs communication without using a spread spectrum method,
The base station according to claim 5. The first terminal is a terminal whose communication quality is equal to or higher than a predetermined value,
The second terminal is a terminal that communicates without using a spread spectrum method, a terminal that communicates using a spread spectrum method and the communication quality is less than the predetermined value, and a terminal that transmits information of high importance. is one of the devices that
The base station according to claim 5. a classification unit that determines a group of first channels in which the amount of interference is greater than a first threshold;
a control unit that assigns a first terminal using a spread spectrum method to a second channel included in the first channel group;
Equipped with
The control unit is configured such that, in the interference of the first channel, interference from a wireless device that transmits a signal using a spread spectrum method is smaller than interference from a wireless device that transmits a signal without using a spread spectrum method. assigning the first terminal to the first channel;
The first terminal communicates using a spread spectrum method,
base station. A wireless communication system comprising a base station and a terminal wirelessly connected to the base station,
The base station is
a classification unit that determines a group of first channels in which the amount of interference is greater than a first threshold;
a control unit that assigns a first terminal to a second channel included in the first channel group;
Equipped with
The first terminal is
a transmitter that transmits a transmission signal generated using a spread spectrum method to the base station in the second channel;
Equipped with
The control unit assigns a second terminal different from the first terminal to a channel different from the first channel,
The second terminal is a terminal that performs communication without using a spread spectrum method,
Wireless communication system. determining a first group of channels whose amount of interference is greater than a first threshold;
Allocating a first terminal using a spread spectrum method to a second channel included in the first channel,
assigning a second terminal different from the first terminal to a channel different from the first channel;
The second terminal is a terminal that performs communication without using a spread spectrum method,
Control method.

Images