JP7670508B2 - Base station and control method - Google Patents

Description

The present disclosure relates to a base station and a control method.

In communications between a base station and a terminal, for example, the base station may assign a channel to be used for wireless communications to the terminal. In this case, the terminal transmits signals to the base station on the assigned channel and receives signals from the base station.

Depending on the environment of the communication range covered by a base station, multiple terminals may move together from inside to outside the communication range or from outside to inside the communication range on a specific schedule (e.g., at a specific timing or within a specific period of time).

JP 2013-172407 A

However, there is room for improvement in terms of appropriate channel allocation that takes into account terminal movement schedules.

Non-limiting examples of the present disclosure contribute to providing a base station, a terminal, and a control method that can perform appropriate channel allocation taking into account the schedule of terminal movement.

A base station according to one embodiment of the present disclosure includes a receiving unit that receives, from each terminal within a communication range, schedule information regarding the timing of leaving the communication range, and a control unit that assigns the terminal to each channel based on the schedule information.

A terminal according to one embodiment of the present disclosure includes a transmission unit that transmits schedule information regarding the timing of going outside the communication range of a base station to the base station, and a control unit that controls data transmission using the channel assigned based on the schedule information.

In a control method according to one embodiment of the present disclosure, a base station receives schedule information from each terminal within its communication range regarding the timing of leaving the communication range, and assigns the terminal to each channel based on the schedule information.

These comprehensive or specific aspects may be realized as a system, device, method, integrated circuit, computer program, or recording medium, or as any combination of a system, device, method, integrated circuit, computer program, and recording medium.

According to one embodiment of the present disclosure, appropriate channel allocation can be performed taking into account the terminal movement schedule.

Further advantages and benefits of an embodiment of the present disclosure will become apparent from the specification and drawings. Such advantages and/or benefits may be provided by some of the embodiments and features described in the specification and drawings, respectively, but not necessarily all of them need be provided to obtain one or more identical features.

FIG. 1 shows an example of users and communication ranges on a station platform. FIG. 2 is a diagram showing an example of channel allocation in the example shown in FIG. 1; FIG. 3 is a diagram showing an example of a state after the wireless connection of the first terminal is disconnected in the channel allocation shown in FIG. FIG. 1 is a block diagram showing a configuration example of a base station according to an embodiment; FIG. 1 is a block diagram showing a configuration example of a terminal according to an embodiment; FIG. 1 is a diagram showing an example of a frame configuration of schedule information transmitted by a terminal according to an embodiment; FIG. 1 shows an example of channel allocation in a first example. FIG. 8 is a diagram showing an example of a state after the wireless connection of the first terminal is disconnected in the channel allocation shown in FIG. A flowchart showing an example of a processing flow of a base station in a first example of the present embodiment. FIG. 11 is a diagram showing an example of channel allocation in the second example. FIG. 11 is a diagram showing an example of a state after the wireless connection of the third terminal is disconnected in the channel allocation shown in FIG. A flowchart showing an example of a processing flow of a base station in a second example of the present embodiment. FIG. 11 is a diagram showing a second example of a frame configuration of schedule information transmitted by a terminal according to the present embodiment. FIG. 13 is a diagram showing an example of channel allocation in the third example. FIG. 15 is a diagram showing an example of a state after the wireless connection of a fifth terminal is disconnected in the channel allocation shown in FIG. A flowchart showing an example of a processing flow of a base station in a third example of the present embodiment. FIG. 13 is a diagram showing an example of channel allocation in the fourth example. FIG. 18 is a diagram showing an example of a state after some wireless connections of the fifth terminal and the seventh terminal are disconnected in the channel allocation shown in FIG. 17; A flowchart showing an example of a processing flow of a base station in a fourth example of the present embodiment. FIG. 1 is a block diagram showing a configuration example of a base station according to an embodiment of the present invention; FIG. 13 is a diagram showing an example of channel allocation in the fifth example. A flowchart showing an example of a processing flow of a base station in a fifth example of the present embodiment. FIG. 13 is a diagram showing an example of channel allocation in the sixth example. A flowchart showing an example of a processing flow of a base station in a sixth example of the present embodiment. FIG. 13 is a diagram showing an example of channel allocation in the seventh example. A flowchart showing an example of a processing flow of a base station in a seventh example of the present embodiment.

A preferred embodiment of the present disclosure will be described in detail below with reference to the attached drawings. In this specification and drawings, components having substantially the same functions are designated by the same reference numerals to avoid redundant description.

<Findings that led to the present disclosure>
For example, on a station platform (hereinafter sometimes abbreviated as "station"), many railroad passengers (hereinafter sometimes abbreviated as "users") wait for the arrival of a railroad car (hereinafter sometimes abbreviated as "train"). A terminal owned by the user wirelessly connects to a base station and performs wireless communication using a channel assigned by the base station.

Figure 1 shows an example of users and communication ranges at a station. Figure 1 shows the communication range Ar of a base station that covers two platforms, and two user groups (user group #1 and user group #2).

User group #1 is a group of users who plan to board train #1 traveling in the direction of arrow A. User group #2 is a group of users who plan to board train #2 traveling in the direction of arrow B.

The base station wirelessly connects to terminals owned by users of two user groups included in the base station's communication range Ar, assigns each terminal to a channel, and performs wireless communication with the terminals.

When a train arrives at a station, users who are using the arriving train board the train. On the other hand, users who are not using the arriving train (for example, users who are heading to a destination different from that of the arriving train) and users who disembark from the arriving train remain on the station platform. Hereinafter, users who board a train may be referred to as boarding users, and users who do not board a train may be referred to as remaining users.

For example, in FIG. 1, users in user group #1 are users boarding train #1 when train #1 arrives at the station, and are staying users when train #2 arrives at the station. Users in user group #2 are users staying at the station when train #1 arrives at the station, and are users boarding train #2 when train #2 arrives at the station.

The train with the boarding user departs for the next station. In this case, the boarding user's terminal goes out of the communication range of the base station as the train moves. On the other hand, the terminal of the remaining user remains within the communication range of the base station. As a result, the channel assigned to the boarding user's terminal by the base station has an increasing amount of free space as the train moves, and in some cases, the channel may become vacant. In this case, channel assignment becomes biased, and frequency utilization efficiency may decrease.

For example, in the example of Figure 1, if train #1 arrives at the station and departs from the station while train #2 has not yet arrived at the station, the terminals of users riding on train #1 will fall out of the communication range Ar. Meanwhile, the terminals of users in user group #2 will remain on the platform. In this case, the channels assigned to the terminals of users in user group #1 will see an increase in available capacity as train #1 moves, while the channels assigned to the terminals of users in user group #2 will not see an increase in available capacity.

Next, an example of channel allocation to a terminal of a user in user group #1 and a terminal of a user in user group #2 will be described. Note that, below, a terminal of a user in user group #1 may be described as a "first terminal," and a terminal of a user in user group #2 may be described as a "second terminal."

Figure 2 is a diagram showing an example of channel allocation in the example shown in Figure 1. The horizontal axis of Figure 2 indicates frequency, and the vertical axis indicates the number of assigned terminals. Figure 2 shows four channels with center frequencies f1 to f4, and terminals assigned to each channel. Hereinafter, the four channels with center frequencies f1 to f4 may be referred to as channel f1 to channel f4, respectively.

In addition, in FIG. 2, the first terminals #a-#b, #c-#d, and the second terminals #A-#B, #C-#D are different terminals from each other. The first terminals #a-#b and #c-#d are terminals owned by users in user group #1 shown in FIG. 1, and the second terminals #A-#B and #C-#D are terminals owned by users in user group #2 shown in FIG. 1.

In the example of FIG. 2, the first terminals #a-#b are assigned to channel f1, and the first terminals #c-#d are assigned to channel f2. Also, in the example of FIG. 2, the second terminals #A-#B are assigned to channel f3, and the second terminals #C-#D are assigned to channel f4.

For example, if users in user group #1 shown in FIG. 1 board train #1 that has arrived at a station, and then train #1 departs from the station and moves outside communication range Ar, the wireless connection between first terminals #a-#b and first terminals #c-#d and the base station is disconnected. When the wireless connection is disconnected, the channel resources assigned to first terminals #a-#b and first terminals #c-#d become free resources.

Figure 3 shows an example of the state after the wireless connection of the first terminal is disconnected in the channel allocation shown in Figure 2.

For example, in the channel allocation shown in Figure 2, if the resources of the channels assigned to the first terminals #a-#b and #c-#d become free resources, as shown in Figure 3, channel f1 and channel f2 become free channels, while channel f3 assigned to the second terminals #A-#B and channel f4 assigned to the second terminals #C-#D become congested.

In other words, in the example shown in Figure 3, even though channels f1 and f2 are free channels, channels f3 and f4 are congested, resulting in reduced frequency utilization efficiency.

In Figures 1 to 3, as an example, a base station that covers the premises of a station including the platform has been described, but in various environments other than station premises, such as places where buses, planes, and ships depart and arrive (e.g., bus stops, airports, ports), some of the multiple terminals present within the communication range of the base station may move out of the communication range as a group. Even in such cases, there is a possibility that the frequency utilization efficiency will decrease, as in the examples shown in Figures 2 and 3.

In a non-limiting embodiment of the present disclosure, information regarding the movement of a terminal is obtained from the terminal, and channel allocation is performed based on the obtained information, thereby suppressing a decrease in frequency utilization efficiency.

The wireless communication system according to this embodiment includes a base station 100 shown in FIG. 4 and a terminal 200 shown in FIG. 5.

<Example of base station configuration>
4 is a block diagram showing an example of the configuration of base station 100 according to this embodiment. Base station 100 includes receiving section 101, demodulation/decoding section 102, schedule information extraction section 103, allocation control section 104, control information generation section 105, encoding/modulation section 106, and transmission section 107.

The receiving unit 101 receives a signal transmitted by the terminal 200 and performs a predetermined receiving process on the received signal. For example, the predetermined receiving process includes a frequency conversion process (down-conversion). For example, the receiving unit 101 performs a frequency conversion process on the received signal based on the frequency of the channel assigned to the terminal 200. Information on the frequency of the channel assigned to the terminal 200 may be acquired, for example, from the allocation control unit 104. Alternatively, the receiving unit 101 may perform a frequency conversion process on the received signal including the control information based on the frequency of the predetermined channel. The receiving unit 101 outputs the received signal that has been subjected to the predetermined receiving process to the demodulation/decoding unit 102.

The demodulation/decoding unit 102 performs demodulation and decoding on the received signal acquired from the receiving unit 101 to generate received data and/or control information. The control information may include schedule information transmitted by the terminal 200. The demodulation/decoding unit 102 outputs the received data and/or control information to the allocation control unit 104. The demodulation/decoding unit 102 also outputs the control information to the schedule information extraction unit 103.

The schedule information extraction unit 103 extracts the schedule information contained in the control information and outputs the extracted schedule information to the allocation control unit 104.

The allocation control unit 104 controls data communication with the terminal 200. For example, the allocation control unit 104 may output received data acquired from the demodulation/decoding unit 102 to an external device (not shown). The allocation control unit 104 also outputs transmission data addressed to the terminal 200 acquired from an external device (not shown) to the encoding/modulation unit 106.

The allocation control unit 104 allocates channels to the terminal 200 based on the control information (schedule information) received from the terminal 200. The allocation control unit 104 outputs allocation information indicating the channels allocated to the terminal 200 to the receiving unit 101, the transmitting unit 107, and the encoding/modulating unit 106. An example of channel allocation will be described later.

The control information generating unit 105 generates control information addressed to the terminal 200 based on the allocation information acquired from the allocation control unit 104. The control information generating unit 105 outputs the control information to the encoding/modulation unit 106.

The coding/modulation unit 106 performs coding and modulation processes on the transmission data acquired from the allocation control unit 104 to generate a transmission data signal. The coding/modulation unit 106 also performs coding and modulation processes on the control information acquired from the control information generation unit 105 to generate a transmission control signal. The coding/modulation unit 106 outputs the transmission signal (the transmission data signal and/or the transmission control signal) to the transmission unit 107.

The transmitting unit 107 performs a predetermined transmission process on the transmission signal acquired from the encoding/modulation unit 106, and transmits the transmission signal after the transmission process to the terminal 200. For example, the predetermined transmission process includes a frequency conversion process (up-conversion). For example, the transmitting unit 107 performs a frequency conversion process on the transmission data signal addressed to the terminal 200, based on the frequency of the channel assigned to the terminal 200. Allocation information regarding the frequency of the channel assigned to the terminal 200 may be acquired, for example, from the channel allocation unit 105. Alternatively, the transmitting unit 107 may perform a frequency conversion process on the received signal including control information, based on the frequency of the predetermined channel.

<Example of terminal configuration>
5 is a block diagram showing an example of the configuration of terminal 200 according to this embodiment. Terminal 200 includes receiving section 201, demodulation/decoding section 202, schedule information generating section 203, allocation control section 204, coding/modulation section 205, and transmission section 206.

The receiving unit 201 receives a signal transmitted by the base station 100 and performs a predetermined receiving process on the received signal. For example, the predetermined receiving process includes a frequency conversion process (down-conversion) based on the frequency of the channel used for reception. Information on the frequency of the channel used for reception may be acquired, for example, from the allocation control unit 204. Alternatively, the receiving unit 201 may perform a frequency conversion process based on the frequency of the predetermined channel on the received signal including the control information. The receiving unit 201 outputs the received signal that has been subjected to the predetermined receiving process to the demodulation/decoding unit 202.

The demodulation/decoding unit 202 performs demodulation and decoding on the received signal acquired from the receiving unit 201 to generate received data and/or control information. The demodulation/decoding unit 202 outputs the received data or control information to the allocation control unit 204. Note that the control information includes information on the channel allocated to the terminal 200.

The schedule information generating unit 203 acquires information about the user's schedule from the user who owns the terminal 200 via an operation unit (not shown). The schedule information generating unit 203 generates schedule information based on the information about the user's schedule. The schedule information in this embodiment may be information about the timing at which the terminal 200 leaves (moves outside) the communication range of the base station 100 to which the terminal 200 is wirelessly connected. Note that the timing may refer to a time or a period (or a period). The time span that the timing refers to is not particularly limited, and may be, for example, a span between certain times. Examples of schedule information will be described later.

The allocation control unit 204 controls data communication with the base station 100. For example, the allocation control unit 204 may output received data acquired from the demodulation/decoding unit 202 to a processing unit of an upper layer (not shown). The allocation control unit 204 also outputs transmission data addressed to the base station 100 acquired from a processing unit of an upper layer (not shown) to the encoding/modulation unit 205.

The allocation control unit 204 may also generate control information including the schedule information acquired from the schedule information generation unit 203. The allocation control unit 204 outputs the control information to the coding/modulation unit 205.

The allocation control unit 204 also sets the channel to be used for communication based on the control information included in the received signal received from the base station 100, and outputs information about the set channel to the transmitting unit 206 and the receiving unit 201.

The coding/modulation unit 205 performs coding and modulation processing on the transmission data and/or control information acquired from the allocation control unit 204 to generate a transmission signal. The coding/modulation unit 205 outputs the transmission signal to the transmission unit 206.

The transmitting unit 206 performs a predetermined transmission process on the transmission signal obtained from the encoding/modulation unit 205, and transmits the transmission signal after the transmission process to the base station 100. For example, the predetermined transmission process includes a frequency conversion process (up-conversion) based on the frequency of the channel assigned to the terminal 200. Information on the frequency of the channel assigned to the terminal 200 may be obtained, for example, from the allocation control unit 204. Alternatively, the transmitting unit 206 may perform a frequency conversion process based on the frequency of the predetermined channel on the received signal including the control information.

<Information sent by the device>
Next, an example of schedule information transmitted from the terminal 200 to the base station 100 will be described. In the following, information transmitted from the terminal 200 present in the station premises illustrated in Fig. 1 to the base station 100 that covers the station premises in its communication range will be taken as an example.

For example, in an application installed on the terminal 200, the user who owns the terminal 200 inputs information, and schedule information is determined based on the input information. The information included in the schedule information may be information input in advance, such as when registering a user in the application (e.g., a user ID), or may be information input when using the application (e.g., when using a station).

Figure 6 shows an example of the frame structure of schedule information transmitted by a terminal according to this embodiment.

The schedule information in the frame configuration shown in Figure 6 includes "user ID", "destination information", and "train attribute information".

The user ID is identification information that identifies the user who owns the terminal 200. Note that the user ID may be replaced with information that identifies the terminal (terminal ID).

Destination information is information indicating the destination of the user who owns the terminal 200. For example, the destination information may indicate the direction of the train the user will board (e.g., arrow A or arrow B (see FIG. 1)), may indicate the terminal station of the train the user will board, or may indicate the station where the user plans to get off.

Train attribute information is information that indicates the attributes of the train that the user is riding on. For example, the train attribute information may indicate the type of train. The type of train may be, for example, a local train, an express train, a rapid train, or a limited express train. The train attribute information may also be information about the train route (for example, the railway company).

The schedule information is not limited to the example in FIG. 6, and may be changed depending on the communication range of the base station 100. For example, when the communication range of the base station 100 is a station where trains traveling in one specific direction depart and arrive (e.g., the starting station of a specific line), the destination information will be the same, so the destination information may be omitted. Alternatively, when the communication range of the base station 100 is a station where one type of train departs and arrives (e.g., a station where no trains other than local trains stop), the train attribute information will be the same, so the train attribute information may be omitted.

The schedule information may also include identification information specific to the train the user boards, or may include information on the departure time of the train the user boards. Furthermore, even if the destination is the same, the transfer route of the train may be different. For example, among users departing from S station and heading to T station, there may be a user (hereinafter referred to as user #α) who travels from S station to U station by train #W, and transfers from train #W to train #X at U station to head to T station, and a user (hereinafter referred to as user #β) who travels from S station to V station by train #Y, and transfers to train #Z at V station to head to T station. In this way, when there is a difference in the transfer route, even if the destination is the same, the train to board at S station is different, so the schedule information may include transfer route information. Here, this transfer route information can be substituted with, for example, information on major stations along the way. In the above example of user #a and user #b, the schedule information of user #α may include transfer route information indicating that the intermediate station is station U, and the schedule information of user #β may include transfer route information indicating that the intermediate station is station V.

<First Example>
As a first example, as shown in FIG. 1, a case will be described in which base station 100 covers a platform of a station where train #1 traveling in the direction of arrow A and train #2 traveling in the direction of arrow B opposite to arrow A depart and arrive.

In this case, the destination information in the schedule information received from the terminal 200 of the user riding on train #1 is different from the destination information in the schedule information received from the terminal 200 of the user riding on train #2. The base station 100 assigns the terminal 200 to a channel, for example, based on the destination information.

Figure 7 is a diagram showing an example of channel allocation in the first example. The horizontal axis of Figure 7 indicates frequency, and the vertical axis indicates the number of assigned terminals. Figure 7 shows a first terminal and a second terminal assigned to each of channels f1 to f4.

In the example of FIG. 7, the number of first terminals assigned to each of channels f1 to f4 is the same. Also, the number of second terminals assigned to each of channels f1 to f4 is the same. In other words, when the number of first terminals is 4N (N is an integer equal to or greater than 1), the number of first terminals #a to #b, first terminals #c to #d, first terminals #e to #f, and first terminals #g to #h is N. Similarly, when the number of second terminals is 4M (M is an integer equal to or greater than 1), the number of second terminals #A to #B, second terminals #C to #D, second terminals #E to #F, and second terminals #G to #H is M.

In the example of FIG. 7, the number of first terminals assigned is the same between channels, but the number of first terminals assigned may differ between channels. For example, if the numbers of first terminals assigned to channels f1 to f4 are defined as C1 to C4 (C1 to C4 are integers equal to or greater than 0), respectively, C1 to C4 may be the same number. Alternatively, in this case, the difference between the maximum and minimum values among C1 to C4 may be equal to or less than a predetermined value. Alternatively, the standard deviation of C1 to C4 may be equal to or less than a predetermined value. Alternatively, the numerical range indicated by the values of C1 to C4 may be equal to or less than a predetermined range.

For example, the base station 100 receives schedule information from each of the terminals 200, and divides the terminals 200 into groups based on the schedule information. For example, one group includes terminals 200 (in the first example, terminals 200 of users with the same destination) that will leave the communication range of the base station 100 within a predetermined time. The base station 100 then assigns a first terminal corresponding to the terminal 200 of a user riding on train #1 (e.g., a user with the same destination) to a channel such that the number of terminals assigned to each channel is approximately uniform. The base station 100 also assigns a second terminal corresponding to the terminal of a user riding on train #2 (e.g., a user with the same destination) to a channel such that the number of terminals assigned to each channel is approximately uniform. By such assignment control, the base station 100 performs channel assignment as shown in FIG. 7, for example.

For example, if a user in user group #1 shown in FIG. 1 boards train #1 that has arrived at a station, and then train #1 departs from the station and moves outside the communication range Ar of base station 100, the wireless connections between first terminals #a-#b, first terminals #c-#d, first terminals #e-#f, and first terminals #g-#h and base station 100 are disconnected.

Figure 8 shows an example of the state after the wireless connection of the first terminal is disconnected in the channel allocation shown in Figure 7.

When the wireless connection of the first terminal is disconnected and the resources of the channel to which the first terminal is assigned become free resources in the channel assignment shown in FIG. 7, the amount of free resources becomes uniform among the channels, and the amount of resources used becomes uniform among the channels, as shown in FIG. 8. In other words, by performing channel assignment as shown in FIG. 7, the degree of congestion of each channel (e.g., the number of assigned terminals) can be made approximately equal among the channels, improving frequency utilization efficiency.

<Processing flow of the base station in the first example>
Next, an example of the processing flow of the base station 100 in the first example described above will be described. FIG. 9 is a flowchart showing an example of the processing flow of the base station 100 in the first example of this embodiment. For example, the processing shown in the flowchart of FIG. 9 may be started periodically, or may be started in response to traffic fluctuations (for example, when the number of terminals increases or decreases by a predetermined number or more). In addition, an example of allocating the terminal 200 to an allocatable channel #i will be shown below. Note that i represents a channel index and is an integer between 0 and K-1. K represents the number of allocatable channels and is an integer of 1 or more.

The base station 100 receives schedule information including destination information from the terminal 200 (S101).

The base station 100 determines the number of terminals that have transmitted the same destination information (S102). In the example of FIG. 7, the base station 100 determines the number of first terminals that have transmitted destination information indicating that they will use train #1, and the number of second terminals that have transmitted destination information indicating that they will use train #2. In other words, the base station 100 sets one group for the terminals 200 that have transmitted the same destination information, and determines the number of terminals in the group.

The base station 100 determines the number of terminals to be assigned to each channel based on the determined number of terminals and the number of allocatable channels (S103). For example, the base station 100 determines a first predetermined value for the number of first terminals to be assigned to one channel and a second predetermined value for the number of second terminals to be assigned to one channel. For example, as shown in the example of FIG. 7, if the number of first terminals is 4N, the number of second terminals is 4M, the number of channels is 4, and the first terminals and second terminals are uniformly assigned to four channels, the first predetermined value may be 4N/4 and the second predetermined value may be 4M/4. However, if the number of terminals is not an integer multiple of the number of allocatable channels, the number of terminals assigned to each channel will not be completely uniform, but the difference in the number of terminals is considered to be sufficiently small, so it is considered that there will be no significant impact.

In addition, a predetermined value may be determined for each of the allocatable channels. For example, if the number of allocatable channels is K, the base station 100 may determine a first predetermined value and a second predetermined value for each of the K channels. That is, in this case, K first predetermined values and K second predetermined values are determined.

For example, if the number of first terminals is N, the base station 100 may determine each of the K first predetermined values from among any positive integer greater than or equal to ((N/K)-α) and less than or equal to ((N/K)+α). In this case, the base station 100 may determine each of the K first predetermined values such that the sum of the K first predetermined values is N.

Similarly, when the number of second terminals is M, the base station 100 may determine each of the K second predetermined values from among any positive integer between ((M/K)-α) and ((M/K)+α). In this case, the base station 100 may determine each of the K second predetermined values such that the sum of the K second predetermined values is M.

For example, when N=8, M=13, K=4, and α=1, the base station 100 determines four first predetermined values among positive integers between 1 and 3 inclusive such that the sum of the four first predetermined values is 8. In this case, the base station 100 also determines four second predetermined values among positive integers between 9/4 and 17/4 inclusive such that the sum of the four second predetermined values is 12. For example, the four second predetermined values may take the combination of {3, 3, 3, 4}. Also, for example, the four first predetermined values may take the combination of {3, 3, 3, 3}, {1, 2, 2, 3}, {1, 1, 3, 3}, etc.

Note that the above-mentioned method of setting the predetermined value is one example, and the present disclosure is not limited thereto. For example, the above-mentioned method of setting the predetermined value is implemented based on the number of terminals, but may be implemented based on the channel occupancy rate of each terminal instead of the number of terminals.

Alternatively, instead of determining a predetermined value representing the number of terminals to be assigned to each channel, a numerical range indicating an upper and lower limit of the number of terminals to be assigned to each channel may be determined.

From S104 onwards, the base station 100 performs channel allocation processing for the first terminal and channel allocation processing for the second terminal.

The base station 100 sets the channel index i to 0 to process the channel allocation for the first terminal (S104).

The base station 100 determines whether channel allocation to the first terminal is complete (S105).

If channel allocation to the first terminal is not complete (NO in S105), that is, if there is a first terminal to which no channel has been allocated (an unallocated first terminal), the base station 100 determines whether the number of first terminals to which channel #i has been allocated is equal to or greater than a first predetermined value (S106). Note that if the first predetermined value is determined for each channel, the first predetermined value in S106 may be the first predetermined value for channel #i.

If the number of first terminals already assigned to channel #i is equal to or greater than the first predetermined value (YES in S106), the base station 100 adds 1 to the channel index i (S107). Then, the flow proceeds to S105.

If the number of first terminals already assigned to channel #i is not equal to or greater than the first predetermined value (NO in S106), the base station 100 assigns one of the unassigned first terminals to channel #i (S108). Then, the flow proceeds to S105.

When channel allocation to the first terminal is completed (YES in S105), i.e., when there is no first terminal to which a channel has not been assigned (an unassigned first terminal), the base station 100 sets (resets) the channel index i to 0 in order to process channel allocation to the second terminal (S109).

The base station 100 determines whether channel allocation to the second terminal is complete (S110).

If channel allocation to the second terminal is not complete (NO in S110), that is, if there is a second terminal to which a channel has not been allocated (an unallocated second terminal), the base station 100 determines whether the number of second terminals to which channel #i has been allocated is equal to or greater than a second predetermined value (S111). Note that if the second predetermined value is determined for each channel, the second predetermined value in S111 may be the second predetermined value for channel #i.

If the number of second terminals already assigned to channel #i is equal to or greater than the second predetermined value (YES in S111), the base station 100 adds 1 to the channel index i (S112). Then, the flow proceeds to S110.

If the number of second terminals already assigned to channel #i is not equal to or greater than the second predetermined value (NO in S111), the base station 100 assigns one of the unassigned second terminals to channel #i (S113). Then, the flow proceeds to S110.

When channel allocation to the second terminal is complete (YES in S110), i.e., when there is no second terminal to which a channel has not been assigned (an unassigned second terminal), the flow ends.

By the flow described above, the base station 100 assigns the number of first terminals represented by the first predetermined value and the number of second terminals represented by the second predetermined value to each channel.

As described above, in the first example, the base station 100 groups the terminals 200 according to the destinations of the users who own the terminals 200, and performs channel allocation for the terminals 200 in each group so that the number of terminals assigned to each channel is uniform. With this type of allocation, even if the terminals in a certain group all disconnect wireless connections at once, it is possible to suppress bias in the number of terminals in the channel allocation after disconnection, so that the degree of channel congestion can be made uniform between channels, and frequency utilization efficiency can be improved.

In the above-mentioned first example, two trains with opposite destinations are described as an example, but the present disclosure is not limited to this. The present disclosure may be applied to trains with different destinations in three or more directions. In addition, in the above-mentioned first example, a terminal owned by a user who boards a train is described as an example, but the present disclosure is not limited to this. For example, the present disclosure may be applied to a terminal owned by a user who gets off a train. For example, in the example of FIG. 1, users who get off train #1 may be grouped into user group #3. In this case, channels may be assigned to the terminals of users in user group #3 so that the channels are evenly distributed, similar to the first and second terminals.

<Second Example>
As a second example, a case will be described in which the base station 100 covers the platforms of stations where two trains, which run in the same direction on the same line and stop at different stations, depart and arrive. For example, the two trains in this case correspond to a train that stops at each station on a line and a train that stops at some of the stations on the line. A train that stops at each station on a line is called, for example, a "local train." Also, a train that stops at some of the stations on a line is called an "express train" below.

In this case, the destination information in the schedule information received from the terminal 200 of a user riding on a local train may be the same as the destination information in the schedule information received from the terminal 200 of a user riding on an express train. However, as described above, the schedule information received by the base station 100 includes train attribute information. For example, the train attribute information indicates whether the user who owns the terminal 200 will use a local train or an express train. In the second example, the base station 100 assigns the terminal 200 to a channel based on the destination information and attribute information included in the information received from each terminal 200.

Hereinafter, the terminal 200 owned by a user who uses a local train will be referred to as the third terminal, and the terminal 200 owned by a user who uses an express train will be referred to as the fourth terminal.

Figure 10 is a diagram showing an example of channel allocation in the second example. The horizontal axis of Figure 10 indicates frequency, and the vertical axis indicates the number of assigned terminals. Figure 10 shows a third terminal and a fourth terminal that are assigned to channels f1 to f4, respectively.

In the example of FIG. 10, the number of third terminals assigned to channels f1, f2, f3, and f4 is the same. Also, the number of fourth terminals assigned to channels f1, f2, f3, and f4 is the same. In other words, when the number of third terminals is 4N (N is an integer of 1 or more), the number of third terminals #a-#b, third terminals #c-#d, third terminals #e-#f, and third terminals #g-#h is N. Similarly, when the number of fourth terminals is 4M (M is an integer of 1 or more), the number of fourth terminals #A-#B, fourth terminals #C-#D, fourth terminals #E-#F, and fourth terminals #G-#H is M.

For example, the base station 100 receives schedule information from each terminal 200, and divides the terminals 200 into groups based on the schedule information. For example, one group includes terminals 200 (terminals 200 of users with the same attribute in the second example) that will leave the communication range of the base station 100 within a predetermined time. The base station 100 then assigns channels to a third terminal corresponding to the terminals 200 of users (e.g., users with the same attribute) who board local trains, so that the number of channels assigned to each channel is uniform. The base station 100 also assigns channels to a fourth terminal corresponding to the terminals 200 of users (e.g., users with the same attribute) who board express trains, so that the number of channels assigned to each channel is uniform. By such assignment control, the base station 100 performs channel assignment as shown in FIG. 10, for example.

For example, when a user boards a local train that arrives at a station and then the local train departs from the station and moves outside the communication range of base station 100, the wireless connection between third terminals #a-#b, #c-#d, #e-#f, and #g-#h and base station 100 is disconnected.

Figure 11 shows an example of the state after the wireless connection of the third terminal is disconnected in the channel allocation shown in Figure 10.

When the wireless connection of the third terminal is disconnected and the resources of the channel to which the third terminal is assigned become free resources in the channel assignment shown in FIG. 10, the amount of free resources becomes uniform among the channels, and the amount of resources used becomes uniform among the channels, as shown in FIG. 11. In other words, by performing channel assignment as shown in FIG. 10, the degree of congestion of each channel (e.g., the number of assigned terminals) can be made approximately equal among the channels, improving frequency utilization efficiency.

<Processing flow of base station in second example>
Next, an example of the processing flow of the base station 100 in the above-mentioned second example will be described. Fig. 12 is a flowchart showing an example of the processing flow of the base station 100 in the second example of the present embodiment. In Fig. 12, the same processes as those in Fig. 9 are given the same reference numerals, and the description may be omitted. For example, the process shown in the flowchart in Fig. 12 may be started periodically.

The base station 100 receives schedule information including train attribute information from the terminal 200 (S201).

The base station 100 determines the number of terminals that have transmitted the same train attribute information (S202). In the example of FIG. 10, the base station 100 determines the number of third terminals that have transmitted train attribute information indicating that they will use a local train, and the number of fourth terminals that have transmitted train attribute information indicating that they will use an express train. In other words, the base station 100 sets one group for the terminals 200 that have transmitted the same train attribute information, and determines the number of terminals in the group.

Based on the determined number of terminals and the number of allocatable channels, the base station 100 determines the number of terminals to be assigned to each channel (S203). Here, the predetermined value for the number of third terminals to be assigned to one channel is described as a third predetermined value, and the predetermined value for the number of fourth terminals to be assigned to one channel is described as a fourth predetermined value. Note that the method for determining the predetermined values may be the same as the example shown in S103 of FIG. 9.

After S204, the base station 100 performs channel allocation processing for the third terminal and channel allocation processing for the fourth terminal. Note that the channel allocation processing for the third terminal and the channel allocation processing for the fourth terminal are similar to the channel allocation processing for the first terminal and the channel allocation processing for the second terminal in FIG. 9, respectively, and therefore will not be described.

By the flow described above, the base station 100 assigns the number of third terminals represented by the third predetermined value and the number of fourth terminals represented by the fourth predetermined value to each channel.

As described above, in the second example described above, the base station 100 groups the terminals 200 according to the attributes (types) of the trains used by the users who own the terminals 200, and performs channel allocation for the terminals 200 in each group so that the number of terminals assigned to each channel is uniform. With this type of allocation, even if the terminals in a certain group all disconnect their wireless connections at once, it is possible to suppress bias in the number of terminals in the channel allocation after disconnection, so that the degree of channel congestion can be made uniform between channels, improving frequency utilization efficiency.

In the above-mentioned second example, two types of train attributes are described as an example, but the present disclosure is not limited to this. The present disclosure may be applied to a case where there are three or more types of train attributes (for example, local trains, express trains, and limited express trains, etc.). In addition, in the above-mentioned second example, a user who boards a train is described as an example, but the present disclosure is not limited to this. For example, the present disclosure may be applied to a terminal owned by a user who gets off a train. For example, in the example of FIG. 1, users who get off train #1 may be grouped into user group #3. In this case, channels may be assigned to the terminals of users in user group #3 so that they are evenly distributed among the channels, similar to the first terminal and the second terminal.

<Third Example>
For example, among users using a train, a user who wishes to sit in a seat may not board a crowded train, but may board a later train that is not crowded. In the third example, an example of channel allocation to the terminal 200 based on the content of a user's request will be described. In the following, an example will be described in which a user wishes to use a seat when boarding a train.

Figure 13 is a diagram showing a second example of the frame structure of schedule information transmitted by a terminal according to this embodiment. Note that in Figure 13, the description of the same structure as in Figure 6 may be omitted.

The schedule information in the frame configuration shown in FIG. 13 includes a "user ID", "destination information", "train attribute information", and "request information". Note that the "user ID", "destination information", and "train attribute information" are the same as those in the example of the frame configuration shown in FIG. 6, so their explanation will be omitted.

The request information indicates, for example, whether or not the user requests to sit in a seat on the train that the user is boarding, which is indicated by the destination information and train attribute information. For example, the request information may represent in one bit whether or not the user requests to sit in a seat. Alternatively, if the user requests to sit in a seat, the request information may be included in the schedule information, and if the user does not request to sit in a seat, the request information may not be included in the schedule information.

The user inputs information about the destination, the train to be used, and information indicating whether or not a seat is requested via the terminal 200. The terminal 200 generates schedule information based on the input information and transmits it to the base station 100.

For example, the base station 100 divides (groups) the terminals 200 into a group of terminals 200 of users who wish to sit in a seat and a group of terminals 200 of users who do not wish to sit in a seat, based on the request information included in the schedule information received from each terminal. Hereinafter, the terminals 200 of users who do not wish to sit in a seat are described as the fifth terminals, and the terminals of users who wish to sit in a seat are described as the sixth terminals.

Figure 14 is a diagram showing an example of channel allocation in the third example. The horizontal axis of Figure 14 indicates frequency, and the vertical axis indicates the number of assigned terminals. Figure 14 shows a fifth terminal and a sixth terminal that are assigned to channels f1 to f4, respectively.

In the example of FIG. 14, the number of fifth terminals assigned to channels f1, f2, f3, and f4 is the same. Also, the number of sixth terminals assigned to channels f1, f2, f3, and f4 is the same. That is, when the number of fifth terminals is 4N (N is an integer of 1 or more), the number of fifth terminals #a-#b, fifth terminals #c-#d, fifth terminals #e-#f, and fifth terminals #g-#h is N. Similarly, when the number of sixth terminals is 4M (M is an integer of 1 or more), the number of sixth terminals #A-#B, sixth terminals #C-#D, sixth terminals #E-#F, and sixth terminals #G-#H is M.

For example, the base station 100 receives schedule information from each terminal 200, and divides the terminals 200 into groups based on the schedule information. For example, one group includes terminals 200 that will leave the communication range of the base station 100 within a predetermined time (in the third example, terminals 200 of users with the same desire). The base station 100 then assigns channels to the fifth terminal, which corresponds to the terminal 200 of a user who does not desire to sit in a seat, so that the number of channels assigned to each channel is uniform. The base station 100 also assigns channels to the sixth terminal, which corresponds to the terminal 200 of a user who desires to sit in a seat, so that the number of channels assigned to each channel is uniform. By such assignment control, the base station 100 performs channel assignment as shown in FIG. 14, for example.

For example, if a user who does not wish to sit in a seat boards a train that has arrived at a station, and the train then departs from the station and moves out of the communication range of base station 100, the wireless connections between fifth terminals #a-#b, #c-#d, #e-#f, and #g-#h and base station 100 are disconnected.

Figure 15 shows an example of the state after the wireless connection of the fifth terminal is disconnected in the channel allocation shown in Figure 14.

When the wireless connection of the fifth terminal is disconnected and the resources of the channel to which the fifth terminal is assigned become free resources in the channel assignment shown in FIG. 14, the amount of free resources becomes uniform among the channels, and the amount of resources used becomes uniform among the channels, as shown in FIG. 15. In other words, by performing channel assignment as shown in FIG. 14, the degree of congestion of each channel (e.g., the number of assigned terminals) can be made approximately equal among the channels, improving frequency utilization efficiency.

<Processing flow of base station in third example>
Next, an example of the processing flow of the base station 100 in the above-mentioned third example will be described. Fig. 16 is a flowchart showing an example of the processing flow of the base station 100 in the third example of the present embodiment. In Fig. 16, the same processes as those in Figs. 9 and 12 are given the same reference numerals, and the description may be omitted. For example, the processing shown in the flowchart in Fig. 16 may be started periodically.

The base station 100 receives schedule information including request information from the terminal 200 (S301).

The base station 100 groups the terminals based on the request information and determines the number of terminals in each group (S302). In the example of FIG. 14, the base station 100 determines the number of fifth terminals that have transmitted request information indicating that they do not wish to sit in a seat, and the number of sixth terminals that have transmitted request information indicating that they wish to sit in a seat.

Based on the determined number of terminals and the number of allocatable channels, the base station 100 determines the number of terminals to be assigned to each channel (S303). Here, the predetermined value for the number of fifth terminals to be assigned to one channel is described as the fifth predetermined value, and the predetermined value for the number of sixth terminals to be assigned to one channel is described as the sixth predetermined value. Note that the method for determining the predetermined values may be the same as the example shown in S103 of FIG. 9.

After S304, the base station 100 performs channel allocation processing for the fifth terminal and channel allocation processing for the sixth terminal. Note that the channel allocation processing for the fifth terminal and the channel allocation processing for the sixth terminal are similar to the channel allocation processing for the first terminal and the channel allocation processing for the second terminal in FIG. 9, respectively, and therefore will not be described.

By the flow described above, the base station 100 assigns the number of fifth terminals represented by the fifth predetermined value and the number of sixth terminals represented by the sixth predetermined value to each channel.

As described above, in the third example, the base station 100 groups the terminals 200 based on whether the users who own the terminals 200 request seats, and performs channel allocation for the terminals 200 in each group so that the number of terminals assigned to each channel is uniform. With this type of allocation, even if the terminals in a certain group all disconnect wireless connections at once, it is possible to suppress bias in the number of terminals in the channel allocation after disconnection, so that the degree of channel congestion can be made uniform between channels, improving frequency utilization efficiency.

In the above third example, the request information indicating whether or not a seat is requested is used as an example, but the present disclosure is not limited to this. The request information may be used to notify a request other than to sit in a seat. In this case, the base station 100 may group the terminals based on the notified request and assign a channel to each group.

Here, the present disclosure is applicable not only to whether or not a seat is requested to be taken, but also to cases where the user requests that the seat next to the seat in which the user plans to sit be available. In this case, additional information for requesting that the seat next to the seat be available may be added to the seat request information. For example, the additional information is represented by one bit. For example, if the user requests that the seat next to the seat be available, the one bit of additional information is set to "1", and if not, the one bit of additional information is set to "0".

The present disclosure is also applicable to cases where multiple passengers wish to reserve seats together. In this case, seat number information indicating the number of seats that are desired to be reserved together may be added to the seat request information. For example, the seat number information is represented by multiple bits (e.g., 2 bits). For example, the seat number information is set to "1" if the user wishes to sit together with one other person or two other people, set to "2" if the user wishes to sit together with three people, and set to "3" if four people wish to sit together.

Furthermore, the present disclosure is also applicable to cases where a user wishes to specify a vehicle in which a seat is to be reserved. In this case, vehicle information indicating the vehicle in which a seat is to be reserved may be added to the seat request information. For example, the vehicle information is represented by multiple bits (e.g., 3 bits). For example, the vehicle information is set to "0" if the user wishes to reserve a seat in the first vehicle, set to "3" if the user wishes to reserve a seat in the fourth vehicle from the front, and set to "7" if the user wishes to reserve a seat in the eighth vehicle from the front.

<Fourth Example>
In each of the above-mentioned examples, each of the terminals 200 transmits schedule information to the base station 100, and the base station 100 performs channel allocation based on the schedule information of each of the terminals 200. On the other hand, there may be a terminal 200 that does not transmit schedule information.

For example, a user can input a destination, etc., via an application installed in the terminal 200, and the terminal 200 can transmit schedule information to the base station 100 based on the information input by the user. On the other hand, if the application is not installed in the terminal 200, the terminal 200 cannot transmit schedule information to the base station 100. In addition, there are cases where a user does not transmit schedule information via the terminal 200, taking into consideration the time spent at a station, etc.

In the fourth example, channel allocation is described when a terminal 200 that does not transmit schedule information is present. Hereinafter, the terminal 200 that does not transmit schedule information is referred to as the seventh terminal.

As a fourth example, channel allocation will be described for the case where there is a terminal 200 in the above third example that does not transmit schedule information. That is, an example will be described in which there is a fifth terminal corresponding to the terminal 200 of a user who does not wish to sit in a seat, a sixth terminal corresponding to the terminal 200 of a user who wishes to sit in a seat, and a seventh terminal corresponding to the terminal 200 that does not transmit schedule information.

Figure 17 is a diagram showing an example of channel allocation in the fourth example. The horizontal axis of Figure 17 indicates frequency, and the vertical axis indicates the number of assigned terminals. Figure 17 shows a fifth terminal, a sixth terminal, and a seventh terminal that are assigned to channels f1 to f4, respectively.

In the example of FIG. 17, the number of fifth terminals assigned to channels f1, f2, f3, and f4 is approximately the same. The number of sixth terminals assigned to channels f1, f2, f3, and f4 is approximately the same. The number of seventh terminals assigned to channels f1, f2, f3, and f4 is approximately the same. That is, when the number of fifth terminals is 4N (N is an integer of 1 or more), the number of fifth terminals #a-#b, fifth terminals #c-#d, fifth terminals #e-#f, and fifth terminals #g-#h is N. Similarly, when the number of sixth terminals is 4M (M is an integer of 1 or more), the number of sixth terminals #A-#B, sixth terminals #C-#D, sixth terminals #E-#F, and sixth terminals #G-#H is M. Similarly, if the number of seventh terminals is 4L (L is an integer equal to or greater than 1), the number of seventh terminals #p to #q, seventh terminals #r to #s, seventh terminals #t to #u, and seventh terminals #v to #w is L.

For example, the base station 100 receives schedule information from each of the terminals 200, and divides the terminals 200 into groups based on the schedule information. Here, in the fourth example, the base station 100 divides the terminals 200 that are wirelessly connected to the base station 100 (e.g., have established a wireless link) and that do not transmit schedule information into a separate group from the terminals 200 that have transmitted schedule information. For example, the group of terminals 200 that do not transmit schedule information may be described as a group of unreported users.

Then, the base station 100 assigns channels to the fifth terminal, which corresponds to the terminal 200 of a user who does not wish to sit in a seat, so that the number assigned to each channel is uniform. The base station 100 also assigns channels to the sixth terminal, which corresponds to the terminal 200 of a user who wishes to sit in a seat, so that the number assigned to each channel is uniform. The base station 100 also assigns channels to the seventh terminal, which corresponds to the terminal 200 that does not transmit schedule information, so that the number assigned to each channel is uniform. By using this type of assignment control, the base station 100 performs channel assignment as shown in FIG. 17, for example.

For example, if a user who does not wish to sit in a seat boards a train that has arrived at a station, and the train then departs from the station and moves out of the communication range of base station 100, the wireless connections between fifth terminals #a-#b, fifth terminals #c-#d, fifth terminals #e-#f, and fifth terminals #g-#h and base station 100 are disconnected. In addition, there is a possibility that some of the users who own terminals 200 that do not transmit schedule information will board this train.

Figure 18 shows an example of the state after some of the wireless connections of the fifth terminal and the seventh terminal are disconnected in the channel allocation shown in Figure 17.

When the wireless connection of the fifth terminal is disconnected, and in the channel allocation shown in FIG. 17, the resources of the channel allocated to the fifth terminal become free resources, and some of the resources of the channel allocated to the seventh terminal become free resources, the probability that the amount of free resources will be uneven in each channel can be reduced, as shown in FIG. 18. In other words, by performing channel allocation as shown in FIG. 17, the probability that the degree of congestion in each channel (e.g., the number of assigned terminals) will be uneven can be reduced, and frequency utilization efficiency can be improved.

<Processing flow of the base station in the fourth example>
Next, an example of the processing flow of the base station 100 in the above-mentioned fourth example will be described. Fig. 19 is a flowchart showing an example of the processing flow of the base station 100 in the fourth example of the present embodiment. In Fig. 19, the same processes as those in Figs. 9, 12, and 16 are given the same reference numerals, and the description may be omitted. For example, the process shown in the flowchart in Fig. 19 may be started periodically.

The base station 100 receives schedule information including request information from the terminal 200 (S401). Note that in this case, the base station 100 does not receive schedule information from some of the terminals 200 subordinate to the base station 100.

Based on the request information, the base station 100 divides the terminals into groups and determines the number of terminals in each group (S402). In the example of FIG. 19, the base station 100 determines the number of fifth terminals that have transmitted request information indicating that they do not wish to sit in a seat, and the number of sixth terminals that have transmitted request information indicating that they wish to sit in a seat. The base station 100 also determines the number of seventh terminals that do not receive schedule information, among the terminals 200 that are wirelessly connected.

Based on the determined number of terminals and the number of allocatable channels, the base station 100 determines the number of terminals to be assigned to each channel (S403). Here, the predetermined value for the number of fifth terminals to be assigned to one channel is described as the fifth predetermined value, the predetermined value for the number of sixth terminals to be assigned to one channel is described as the sixth predetermined value, and the predetermined value for the number of seventh terminals to be assigned to one channel is described as the seventh predetermined value. Note that the method for determining the predetermined values may be the same as the example shown in S103 of FIG. 9.

In steps S304 to S313, similar to the example shown in FIG. 16, the base station 100 performs channel allocation processing for the fifth terminal and channel allocation processing for the sixth terminal.

Next, when channel allocation to the sixth terminal is completed (YES in S310), i.e., when there is no sixth terminal to which a channel has not been allocated (an unallocated sixth terminal), the base station 100 sets (resets) the channel index i to 0 in order to process channel allocation to the seventh terminal (S404).

In steps S405 to S408, the base station 100 performs channel allocation processing for the seventh terminal. Note that the channel allocation processing for the seventh terminal is similar to the channel allocation processing for the first terminal and the channel allocation processing for the second terminal in FIG. 9, so a description thereof will be omitted.

If channel allocation to the seventh terminal is complete (YES in S405), i.e., if there is no seventh terminal to which a channel has not been assigned (an unassigned seventh terminal), the flow ends.

By the flow described above, the base station 100 assigns to each channel the number of fifth terminals represented by the fifth predetermined value, the number of sixth terminals represented by the sixth predetermined value, and the number of seventh terminals represented by the seventh predetermined value.

As described above, in the fourth example, the base station 100 groups the terminals 200 based on whether or not the users who own the terminals 200 request seats, and performs channel allocation for the terminals 200 in each group so that the number of terminals assigned to each channel is uniform. The base station 100 also groups the terminals 200 that do not transmit schedule information into another group, and performs channel allocation for the terminals 200 that do not transmit schedule information so that the number of terminals assigned to each channel is uniform. With this type of allocation, even if there is a terminal 200 that does not transmit schedule information, it is possible to reduce the probability that the amount of free resources becomes uneven in each channel, and improve frequency utilization efficiency.

Note that in the above-mentioned fourth example, channel allocation in the case where a terminal 200 that does not transmit schedule information exists in the third example has been described, but the present disclosure is not limited to this. For example, even if a terminal 200 that does not transmit schedule information exists in the first or second example, channel allocation similar to that in the above-mentioned fourth example may be performed.

The channel allocations shown in the first to fourth examples above may be combined as appropriate. For example, in a combination of the first, second, and fourth examples, terminals 200 that do not transmit schedule information are considered at platforms of stations that are in different directions and where express trains and local trains stop. In this case, for example, the terminals 100 may be divided into five groups: terminals of users riding on express trains traveling in direction A, terminals of users riding on local trains traveling in direction A, terminals of users riding on express trains traveling in direction B, terminals of users riding on local trains traveling in direction B, and terminals that do not transmit schedule information. Then, the base station 100 may allocate the number of terminals to each channel equally between the channels for each group.

<Fifth Example>
In the fifth example, an example will be described in which interference occurring in a channel to be assigned is measured and the measurement results are classified to more appropriately assign channels to terminals 200. First, the configuration of a base station in the fifth example will be described.

<Base station configuration>
Fig. 20 is a block diagram showing a configuration example of a base station 300 according to this embodiment. In Fig. 20, the same components as those in Fig. 4 are given the same reference numerals and the description thereof is omitted. In the base station 300 shown in Fig. 20, a communication quality measurement unit 301, a preamble detection unit 302, and an interference classification unit 303 are added to the base station 100 shown in Fig. 4, and the allocation control unit 104 is changed to an allocation control unit 304.

The communication quality measurement unit 301 generates communication quality information based on the received signal acquired from the receiving unit 101. The communication quality information may be, for example, the quality of the received signal (for example, Received Signal Strength Indicator (RSSI)). The communication quality measurement unit 301 outputs the communication quality information to the allocation control unit 304.

The preamble detection unit 302 detects whether or not a preamble is included in the received signal acquired from the receiving unit 101. If a preamble is included, the preamble detection unit 302 determines the type of preamble included in the received signal.

For example, the preamble detection unit 302 calculates the correlation between a preamble used in the communication method used by the terminal 200 and the received signal. If the calculated correlation results in a peak equal to or greater than a predetermined value, the preamble detection unit 302 determines that the received signal contains a preamble used in the communication method used by the terminal 200.

Note that the preamble detection unit 302 detects the preamble regardless of whether the source of the received signal is included in the network (NW) to which the base station 300 belongs. In other words, the preamble detection unit 302 may determine the type of preamble included in a signal transmitted by a wireless device that is not included in the NW to which the base station 300 belongs.

In addition, if the correlation between the preamble used in the communication method used by the terminal 200 and the received signal does not result in a peak equal to or greater than a predetermined value, the preamble detection unit 302 determines that the sender of the received signal is not using the communication method used by the terminal 200.

The preamble detection unit 302 outputs information indicating whether or not the received signal contains a preamble to the interference classification unit 303. The preamble detection unit 302 also outputs the received signal acquired from the receiving unit 101 to the interference classification unit 303.

The interference classification unit 303, for example, classifies the interference in each channel. For example, the interference classification unit 303 performs classification by monitoring the received signal for a specified time in one channel. For example, the interference classification unit 303 may determine the difference in the source of the received signal within the specified time. The interference classification unit 303 calculates the ratio of the time of the received signal for each source to the specified time, and classifies the interference in each channel.

For example, the interference classification unit 303 acquires, via the receiver 101, signals transmitted by terminals 200 under the control of the base station 300 and signals transmitted by wireless devices not under the control of the base station 300. The interference classification unit 303 then classifies the interference caused by the received signal based on the length of the acquired received signal, the power of the received signal, preamble information of the received signal, and source information included in the received signal.

In the following, a wireless device that belongs to a network other than the network to which base station 300 belongs is described as an "unmanaged terminal", and interference caused by a signal transmitted by an "unmanaged terminal" is described as "unmanaged interference". In the following, a terminal 200 that belongs to the network to which base station 300 belongs and is subordinate to base station 300 is described as an "in-management terminal", and interference caused by a signal transmitted by an "in-management terminal" may be described as "in-management interference".

For example, when the result of preamble detection of the received signal is that the preamble cannot be detected, the interference classification unit 303 determines that the received signal is a signal transmitted by a non-managed terminal. Then, the interference classification unit 303 determines that the signal transmitted by the non-managed terminal corresponds to non-managed interference.

Furthermore, when the received signal contains identification information of a terminal 200 under the control of the base station 300 as a result of demodulation and decoding of the received signal, the interference classification unit 303 determines that the received signal is a signal transmitted by an in-management terminal. Then, the base station 300 determines that the signal transmitted by the in-management terminal corresponds to in-management interference.

The interference classification unit 303 classifies the interference as described above for each channel that the base station 300 can assign to the terminal 200, and outputs information indicating the classification result to the allocation control unit 304. The classification result includes at least the amount of unmanaged interference in each channel. The amount of interference may be represented, for example, by the number of unmanaged terminals, by the channel occupancy rate, by the transmission probability, or by the transmission power.

The allocation control unit 304 controls data communication with the terminal 200. For example, the allocation control unit 304 may output received data acquired from the demodulation/decoding unit 102 to an external device (not shown). The allocation control unit 304 also outputs transmission data addressed to the terminal 200 acquired from an external device (not shown) to the encoding/modulation unit 106.

The allocation control unit 304 allocates channels to the terminal 200 based on the control information (schedule information) received from the terminal 200 and the classification result obtained from the interference classification unit 303. The allocation control unit 304 outputs allocation information indicating the channel allocated to the terminal 200 to the receiving unit 101, the transmitting unit 107, and the encoding/modulating unit 106. An example of channel allocation will be described later.

As described above, the base station 300 classifies the interference for each channel and assigns channels based on the classification results and schedule information.

Below, as a fifth example, an example of channel allocation based on the magnitude of non-management interference and the station stay time of the user who owns the terminal 200 will be described. In the fifth example, the base station 300 assigns the terminal 200 whose station stay time is relatively short to a channel with relatively large non-management interference, and assigns the terminal 200 whose station stay time is relatively long to a channel with relatively small non-management interference. In other words, the base station 300 sets a priority order for the terminal 200 based on the station stay time, and assigns a channel with relatively many free resources (e.g., small non-management interference) to the terminal 200 with a high priority order (e.g., a relatively long station stay time).

The method of acquiring information on the station stay time of the user who owns the terminal 200 is not limited. For example, the user who owns the terminal 200 may input the station stay time into the terminal 200, and the terminal 200 may transmit the input information to the base station 300. For example, the input stay time information may be included in the schedule information.

For example, the user base station 300 identifies the train that the user who owns the terminal will board based on the schedule information received from each terminal 200, and identifies the arrival time (or departure time) of the identified train based on station timetable information. The base station 300 may then estimate the user's stay time at the station based on the identified arrival time (or departure time).

Figure 21 is a diagram showing an example of channel allocation in the fifth example. The horizontal axis of Figure 21 indicates frequency, and the vertical axis indicates the transmission probability of the assigned managed terminal. Figure 21 shows managed terminals assigned to each of channels f1 to f4. Figure 21 also shows n managed terminals assigned to any of channels f1 to f4. The transmission probability shown on the vertical axis is determined, for example, based on the number of terminals. For example, the greater the number of assigned terminals, the higher the transmission probability.

In FIG. 21, there is no (or very little) unmanaged interference in channels f1 and f2. Furthermore, unmanaged interference exists in channel f3, and unmanaged interference exists in channel f4 that is greater than that of channel f3. Note that channels f1 and f2 are classified as "channels with little unmanaged interference," and channel f3 is classified as "channels with great unmanaged interference." Furthermore, channel f4 is close to the upper limit value α of the transmission probability, and may therefore correspond to "a channel to which no in-management terminals are assigned."

The "channel with small non-management interference" may be referred to as a "channel with a low occupancy rate of non-management interference" or a "channel with a lot of vacancy". Furthermore, the "channel with large non-management interference" may correspond to a "channel with a high occupancy rate of non-management interference" or a "channel with little vacancy". Furthermore, the "channel to which no in-management terminal is assigned" may correspond to a "channel with no vacancy". For example, the "channel with small non-management interference" and the "channel with large non-management interference" may be classified by comparing a threshold value with the amount of non-management interference, or a predetermined number of channels with large non-management interference may be classified as "channels with large non-management interference" and the remaining channels may be classified as "channels with small non-management interference". This classification may be performed by the base station 300.

In the example of FIG. 21, n managed terminals are arranged in order of the length of time spent at the station (time until the train to be boarded arrives). Of the n managed terminals, the user of managed terminal #1 has the longest time spent at the station, and the user of managed terminal #n has the shortest time spent at the station. In the example of FIG. 21, the n managed terminals are divided into a group of m terminals consisting of managed terminals #1 to #m of users with relatively long stay times, and a group of n-m terminals consisting of managed terminals #m+1 to #n of users with relatively short stay times. Here, m is an integer between 1 and n. For example, m may be determined based on the ratio of availability of channels f1 and f2 to availability of channel f3.

Base station 300 decides to assign managed terminals #1 to #m of users who stay for a relatively long time to channels f1 and f2 with low non-management interference, and decides to assign managed terminals #m+1 to #n of users who stay for a relatively short time to channel f3 with high non-management interference.

The base station 300 further groups the managed terminals that it has decided to assign to channels f1 and f2, and assigns channels to each group. For example, the base station 300 groups the managed terminals of users who board trains traveling in direction A (hereinafter, first managed terminals) and the managed terminals of users who board trains traveling in direction B opposite to direction A (hereinafter, second managed terminals) based on the schedule information transmitted by each managed terminal. Then, the base station 300 assigns the first managed terminals to channels so that the number of the first managed terminals assigned to channel f1 is the same as the number of the first managed terminals assigned to channel f2 (or the difference is within a certain range). The base station 300 also assigns the second managed terminals to channels so that the number of the second managed terminals assigned to channel f1 is the same as the number of the second managed terminals assigned to channel f2 (or the difference is within a certain range).

<Processing flow of base station in the fifth example>
Next, an example of the processing flow of the base station 300 in the above-mentioned fifth example will be described. Fig. 22 is a flowchart showing an example of the processing flow of the base station 300 in the fifth example of the present embodiment. For example, the processing shown in the flowchart of Fig. 22 may be started periodically.

The base station 300 receives schedule information including destination information from the terminal 200 (S501).

The base station 300 measures the interference of channels that can be assigned to the terminal 200 and classifies the measured interference (S502).

Based on the magnitude of the unmanaged interference, the base station 300 classifies the allocatable channels into channels with large unmanaged interference and channels with small unmanaged interference (S503).

The base station 300 determines whether the decision of the channel to be assigned to each terminal 200 has been completed (S504).

If the channel determination has not been completed (NO in S504), i.e., if there is a terminal 200 (hereinafter referred to as "terminal z") for which the assigned channel has not been determined, the base station 300 executes the determination process from S505 onwards for terminal z.

The base station 300 determines whether the time that the user who owns the terminal z stays at the station (e.g., the difference between the arrival time of the train that the user is taking and the current time) is less than a predetermined time (S505).

If the residence time is less than the predetermined time (YES in S505), the base station 300 decides to assign the terminal z to a channel with large unmanaged interference (S506). Then, the flow proceeds to S504.

If the residence time is not less than the predetermined time (NO in S505), the base station 300 decides to assign the terminal z to a channel with low unmanaged interference (S507). Then, the flow proceeds to S504.

When the channel determination is completed (YES in S504), i.e., when there are no terminals for which the assigned channel has not been determined, channel allocation based on the schedule information is performed for terminals that have been determined to be assigned to a channel with small unmanaged interference (S508). Then, the flow ends.

The processing flow in S508 is similar to the processing flow shown in, for example, S102 to S113 in FIG. 9, and therefore description thereof will be omitted. However, the processing flow in FIG. 9 determines the terminal 200 to which each of the assignable channels is assigned, whereas in FIG. 22, the terminal to which each of the assignable channels is assigned is determined for the channel with the smallest unmanaged interference, which is a difference.

As described above, in the fifth example, the base station 300 classifies interference and determines the channel to be assigned to the terminal 200 according to the magnitude of the unmanaged interference. Then, for example, the base station 300 assigns a channel with relatively large unmanaged interference to the terminal 200 owned by a user who stays at the station for a relatively short time. With such an assignment, a channel with small unmanaged interference and good communication quality can be assigned to the terminal 200 that is expected to stay at the station for a relatively long time and to have a high communication frequency. Also, as in the first example, even if a group of terminals simultaneously disconnects wireless connections, the imbalance in the number of terminals can be suppressed in the channel assignment after disconnection, so that the degree of channel congestion can be equalized between channels, and frequency utilization efficiency can be improved.

In the fifth example, the allocatable channels are classified into channels with large unmanaged interference and channels with small unmanaged interference, but the present disclosure is not limited to this. For example, the allocatable channels may be classified into three or more levels based on the magnitude of unmanaged interference of each channel. In this case, for example, the terminals 200 may be divided into three or more groups based on the stay time of the user, and the terminals in each group may be assigned to each of the channels classified into three or more levels.

In the fifth example, the terminals 200 determined to be assigned to a channel with low unmanaged interference are grouped based on schedule information, and the terminals of each group are assigned to a channel; however, the present disclosure is not limited to this. For example, the terminals 200 determined to be assigned to a channel with high unmanaged interference may be grouped based on schedule information, and the terminals of each group may be assigned to a channel. This allows the degree of channel congestion to be equalized between channels, even in channels with high unmanaged interference, and improves frequency utilization efficiency.

In the fifth example, for example, when the terminal 200 uses a communication method called "LoRa" (hereinafter referred to as the "LoRa method"), which is one of the wireless communication technologies called LPWA (Low Power Wide Area) and performs communication using a spectrum spreading method, the transmission power may be set higher for the terminal 200 of a user who stays in a station for a longer period of time. When the terminal 200 uses the LPWA LoRa method, the terminal 200 of a user who stays in a station for a longer period of time may be assigned a larger spreading factor. In this case, the transmission power of the terminal 200 of the user who stays in a station for a longer period of time may be set higher and a larger spreading factor may be assigned.

<Sixth Example>
In the sixth example, as in the fifth example, a case is described in which a base station 300 classifies interference and determines a channel to be assigned to a terminal 200 according to the magnitude of unmanaged interference, and a terminal 200 exists that does not transmit schedule information.

In the sixth example, the base station 300 assigns the terminals 200 that do not transmit schedule information to channels with relatively large non-management interference. As in the fifth example, the base station 300 assigns the terminals 200 that stay at the station for a relatively short time to channels with relatively large non-management interference, and assigns the terminals 200 that stay at the station for a relatively long time to channels with relatively small non-management interference. In other words, the base station 300 sets the priority of the terminals 200 that do not transmit schedule information lower than the terminals 200 that transmit schedule information. The base station 300 then sets the priority of the terminals 200 based on the station stay time among the terminals 200 that transmit schedule information, and assigns the terminals 200 with high priority (e.g., those that stay at the station for a relatively long time) to channels with relatively large vacancies (e.g., channels with small non-management interference).

Figure 23 is a diagram showing an example of channel allocation in the sixth example. The horizontal axis of Figure 23 indicates frequency, and the vertical axis indicates the transmission probability of the assigned managed terminal. Figure 23 shows managed terminals assigned to each of channels f1 to f4. Figure 23 also shows managed terminals assigned to any of channels f1 to f4.

In FIG. 23, as in FIG. 21, there is no (or very little) unmanaged interference in channels f1 and f2. In addition, there is unmanaged interference in channel f3, and there is greater unmanaged interference in channel f4 than in channel f3.

In the example of FIG. 23, managed terminals #1 to #n are terminals 200 that have sent schedule information, and unreported managed terminals #n+1 to #s are terminals 200 that do not send schedule information. Also, in the example of FIG. 23, similar to FIG. 21, managed terminals #1 to #n are arranged in order of the length of time they stay at the station.

Note that m is an integer between 1 and n. For example, m may be determined based on the ratio of the availability of channels f1 and f2 to the availability of channel f3. However, in the sixth example, an in-management terminal that does not transmit schedule information is assigned to channel f3, and therefore the availability of channel f3 for determining m is the availability after an in-management terminal that does not transmit schedule information is assigned.

Base station 300 decides to assign managed terminals #n+1 to #s that do not transmit schedule information to channel f3, which has high non-management interference. Base station 300 then decides to assign managed terminals #1 to #m of users who have relatively long stay times among managed terminals that have transmitted schedule information to channels f1 and f2, which has low non-management interference, and to assign managed terminals #m+1 to #n of users who have relatively short stay times to channel f3, which has high non-management interference.

The base station 300 further groups the managed terminals that it has decided to assign to channels f1 and f2, and assigns a channel to each group. This assignment may be the same as in the fifth example.

<Processing flow of the base station in the sixth example>
Fig. 24 is a flowchart showing an example of a processing flow of the base station 300 in the sixth example of the present embodiment. Note that in Fig. 24, the same processes as those in Fig. 22 are given the same numbers, and the description thereof may be omitted.

If the channel determination has not been completed (NO in S504), i.e., if there is a terminal (hereinafter referred to as "terminal z") for which the assigned channel has not been determined, the base station 300 determines whether terminal z has not transmitted schedule information (determines whether it has not yet been transmitted) (S601).

When terminal z transmits schedule information (NO in S601), base station 300 determines whether the stay time of the user who owns terminal z at the station (e.g., the difference between the arrival time of the train that the user is taking and the current time) is less than a predetermined time (S505).

If the residence time is not less than the predetermined time (NO in S505), the base station 300 decides to assign the terminal z to a channel with low unmanaged interference (S507). Then, the flow proceeds to S504.

If terminal z has not transmitted schedule information (YES in S601), or if the stay time is less than the predetermined time (YES in S505), base station 300 decides to assign terminal z to a channel with large unmanaged interference (S506). Then, the flow proceeds to S504.

As described above, in the sixth example, the base station 300 classifies interference and determines the channel to be assigned to the terminal 200 according to the magnitude of the non-management interference. Then, for example, the base station 300 assigns channels with relatively large non-management interference to terminals 200 that do not transmit schedule information and terminals 200 owned by users who stay at the station for a relatively short time. With such an assignment, it is possible to assign channels with small non-management interference and good communication quality to terminals 200 that stay at the station for a relatively long time and are assumed to communicate frequently. Also, as in the first example, even if a certain group of terminals 200 simultaneously disconnect wireless connections, it is possible to suppress bias in the number of terminals in the channel assignment after disconnection, thereby reducing the probability that the degree of channel congestion becomes uneven between channels and improving frequency utilization efficiency.

When the terminal 200 that does not transmit schedule information and the terminal 200 that transmits schedule information use the LoRa method, the transmission power of the terminal 200 that does not transmit schedule information may be set lower than that of the terminal 200 that transmits schedule information. For example, the transmission power of the terminal 200 that does not transmit schedule information may be set to the minimum of the settable transmission power. Alternatively, when the terminal 200 that does not transmit schedule information and the terminal 200 that transmits schedule information use the LoRa method, the terminal 200 that does not transmit schedule information may be assigned a smaller spreading factor than the terminal 200 that transmits schedule information. For example, SF7 may be assigned to the terminal that does not report.

<Seventh Example>
In the seventh example, as in the fifth and sixth examples, the base station 300 classifies interference and assigns channels to the terminal 200 according to the magnitude of unmanaged interference. This example explains channel assignment when an emergency situation occurs in which it is difficult for trains to depart or arrive due to an accident or disaster.

In the event of an emergency that makes it difficult for trains to depart or arrive at a station, the base station 300 assigns the user's terminal 200 to a channel based on the distance (or time) from the station to the user's destination (e.g., home). Alternatively, the base station 300 may assign the user's terminal 200 to a channel based on whether alternative means other than trains (e.g., at least one of bus, taxi, walking, and bicycle) are available to reach the destination. Here, a user who can use alternative means other than trains to reach the destination may be notified of information such as the stop and/or timetable of the alternative means (e.g., bus, taxi). In addition, a user who agrees to return home by alternative means may notify the base station 300 to that effect, and some kind of special benefit may be added to the user. Alternatively, the base station 300 may notify the terminal 200 of candidates for alternative means for moving from the station where the user is staying, and the user may determine whether there is an alternative means available from the candidates. In this case, the determination result may be notified from the terminal 200 to the base station 300.

For example, the base station 300 assigns the terminal 200 of a user who has an alternative means available to a channel with relatively large non-management interference. The base station 300 assigns the terminal 200 of a user who has a short distance to the destination to a channel with relatively large non-management interference, and assigns the terminal 200 of a user who has a long distance to the destination to a channel with relatively small non-management interference. In other words, the terminal 200 owned by a user who has an alternative means other than trains (e.g., at least one of bus, taxi, walking, and bicycle) to reach the destination may be set to a lower priority than the terminal 200 owned by a user who does not have an alternative means available. The longer the distance to the user's destination, the higher the priority of the terminal 200 owned by the user may be set. The base station 300 assigns the terminal 200 with a high priority to a channel with relatively large vacancies (e.g., a channel with small non-management interference).

The method of acquiring information on the distance to the destination of the user who owns the terminal 200 is not limited. The base station 300 may estimate the distance to the destination based on information on the train that the user will be taking, which is indicated by the schedule information. Alternatively, the user who owns the terminal 200 may input information on the distance to the destination or the user's home address into the terminal 200, and the terminal 200 may transmit the input information to the base station 300. The input information may be included in the schedule information.

In addition, the method by which the user who owns the terminal 200 obtains information regarding whether or not an alternative means is available is not limited. For example, the base station 300 may estimate whether or not an alternative means is available based on information about the train that the user will be taking, which is indicated by the schedule information. Alternatively, the user who owns the terminal 200 may input into the terminal 200 whether or not an alternative means is available, and the terminal 200 may transmit the input information to the base station 300. For example, the input information may be included in the schedule information.

Figure 25 is a diagram showing an example of channel allocation in the seventh example. The horizontal axis of Figure 25 indicates frequency, and the vertical axis indicates the transmission probability of the assigned managed terminal. Figure 25 shows managed terminals assigned to each of channels f1 to f4. Figure 25 also shows managed terminals assigned to any of channels f1 to f4.

In FIG. 25, as in FIG. 21 and FIG. 23, there is no (or very little) unmanaged interference in channels f1 and f2. In addition, there is unmanaged interference in channel f3, and there is greater unmanaged interference in channel f4 than in channel f3.

In the example of FIG. 25, managed terminals #1 to #n are terminals 200 of users for whom alternative means are not available, and mobile managed terminals #n+1 to #s are terminals 200 of users for whom alternative means are available. In addition, in the example of FIG. 25, managed terminals #1 to #n are arranged in order of the distance to the destination. Of the n managed terminals, managed terminal #1 has the longest distance to the destination of the user, and managed terminal #n has the shortest distance to the destination of the user. In the example of FIG. 25, managed terminals #1 to #n are divided into a group of m terminals consisting of managed terminals #1 to #m of users who have a relatively long distance to their destination, and a group of n-m terminals consisting of managed terminals #m+1 to #n of users who have a relatively short distance to their destination.

Note that m is an integer between 1 and n. For example, m may be determined based on the ratio between the availability of channels f1 and f2 and the availability of channel f3. However, in the seventh example, an in-management terminal of a user for which an alternative means is available is assigned to channel f3, and therefore the availability of channel f3 for determining m is the availability after an in-management terminal of a user for which an alternative means is available is assigned.

Base station 300 decides to assign in-management terminals #n+1 to #s of users for whom alternative means are available to channel f3, which has high non-management interference. Base station 300 then decides to assign in-management terminals #1 to #m of users who are relatively far from their destinations, among the in-management terminals of users for whom alternative means are not available, to channels f1 and f2, which has low non-management interference, and to assign in-management terminals #m+1 to #n of users who are relatively close to their destinations to channel f3, which has high non-management interference.

The base station 300 further groups the managed terminals that it has decided to assign to channels f1 and f2, and assigns a channel to each group. This assignment may be the same as in the fifth example.

<Processing flow of base station in seventh example>
Fig. 26 is a flowchart showing an example of a processing flow of the base station 300 in the seventh example of the present embodiment. Note that in Fig. 26, the same processes as those in Fig. 22 are given the same numbers, and the description thereof may be omitted.

If the channel determination has not been completed (NO in S504), i.e., if there is a terminal (hereinafter referred to as "terminal z") for which the assigned channel has not been determined, the base station 300 determines whether the user of terminal z can travel by alternative means (S701).

If the user of terminal z is not able to travel by alternative means (NO in S701), base station 300 determines whether the distance to the destination of the user who owns terminal z is less than a threshold (S702).

If the distance to the destination is not less than the threshold (NO in S702), the base station 300 decides to assign the terminal z to a channel with low unmanaged interference (S704). The flow then proceeds to S504.

If the user of terminal z can travel by alternative means (YES in S701), or if the distance to the destination is less than the threshold (YES in S702), base station 300 decides to assign terminal z to a channel with high unmanaged interference (S703). Then, the flow proceeds to S504.

As described above, in the seventh example, the base station 300 classifies interference and assigns channels to terminals according to the magnitude of unmanaged interference. Then, for example, the base station 300 assigns channels with relatively large unmanaged interference to terminals 200 of users who can use alternative means and terminals 200 owned by users who are relatively close to their destinations. With this assignment, it is possible to assign channels with small unmanaged interference and good communication quality to terminals 200 that are relatively far from their destinations, spend a long time at stations, and are assumed to communicate frequently. Also, as in the first example, even if terminals 200 of a certain group simultaneously disconnect wireless connections, it is possible to suppress bias in the number of terminals in the channel assignment after disconnection, so that the degree of channel congestion can be made equal between channels, and frequency utilization efficiency can be improved.

When the terminal 200 uses the LoRa method of LPWA, the transmission power may be set higher for the terminal 200 of a user whose distance to the destination is relatively longer. Alternatively, when the terminal 200 uses the LoRa method of LPWA, the transmission power may be assigned higher for the terminal 200 of a user whose distance to the destination is relatively longer. In this case, the transmission power of the terminal 200 of the user whose distance to the destination is relatively longer may be set higher and a larger spreading factor may be assigned.

In addition, when the terminal 200 uses the LoRa method of LPWA, the transmission power of the terminal 200 of the user for whom an alternative means is available may be set lower than that of the terminal 200 of the user for whom an alternative means is not available. For example, the transmission power of the terminal 200 of the user for whom an alternative means is available may be set to the minimum of the settable transmission power. Alternatively, when the terminal 200 uses the LoRa method, the terminal 200 of the user for whom an alternative means is available may be assigned a smaller spreading factor than that of the terminal 200 of the user for whom an alternative means is not available. For example, SF7 may be assigned to the terminal 200 of the user for whom an alternative means is available. Alternatively, when the terminal 200 uses the LoRa method, the terminal 200 of the user for whom an alternative means is available may be assigned a smaller spreading factor than that of the terminal of the user for whom an alternative means is not available, and the transmission power may be set lower than that of the terminal 200 of the user for whom an alternative means is not available.

The term "part" in the above embodiment may be replaced with other terms such as "circuitry", "device", "unit", or "module".

In addition, the term "channel" in the above embodiments may be replaced with other terms such as "frequency," "frequency channel," "band," "carrier," "subcarrier," or "(frequency) resource."

This disclosure can be realized as software, hardware, or software in conjunction with hardware.

Each functional block used in the description of the above embodiments may be realized, in part or in whole, as an LSI, which is an integrated circuit, and each process described in the above embodiments may be controlled, in part or in whole, by one LSI or a combination of LSIs. The LSI may be composed of individual chips, or may be composed of one chip that contains some or all of the functional blocks. The LSI may have data input and output. Depending on the level of integration, the LSI may be called an IC, system LSI, super LSI, or ultra LSI.

The integrated circuit method is not limited to LSI, and may be realized by a dedicated circuit, a general-purpose processor, or a dedicated processor. In addition, a field programmable gate array (FPGA) that can be programmed after LSI manufacturing, 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 realized as digital processing or analog processing.

Furthermore, if an integrated circuit technology that can replace LSI emerges due to advances in semiconductor technology or other derived technologies, it is natural that such technology can be used to integrate functional blocks. The application of biotechnology, etc. is also a possibility.

The present disclosure may be implemented in any type of apparatus, device, or system with communication capabilities (collectively referred to as communication devices). Non-limiting examples of communication devices include telephones (e.g., mobile phones, smartphones, etc.), tablets, personal computers (PCs) (e.g., laptops, desktops, notebooks, etc.), cameras (e.g., digital still/video cameras), digital players (e.g., digital audio/video players, etc.), wearable devices (e.g., wearable cameras, smartwatches, tracking devices, etc.), game consoles, digital book readers, telehealth/telemedicine devices, communication-enabled vehicles or mobile transport (e.g., automobiles, airplanes, ships, etc.), and combinations of the above-mentioned devices.

The communication device is not limited to portable or mobile devices, but also includes any type of equipment, device, or system that is non-portable or fixed, such as smart home devices (home appliances, lighting equipment, smart meters or measuring devices, control panels, etc.), vending machines, and any other "things" that may exist on an IoT (Internet of Things) network.

Communications include data communication via cellular systems, wireless LAN systems, communication satellite systems, etc., as well as data communication via combinations of these.

The communication device also includes devices such as controllers and sensors that are connected or coupled to a communication device that performs the communication functions described in this disclosure. For example, the communication device includes a controller or sensor that generates control signals or data signals used by the communication device to perform the communication functions of the communication device.

Communication equipment also includes infrastructure facilities, such as base stations, access points, and any other equipment, devices, or systems that communicate with or control the various non-limiting devices listed above.

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 modified or revised examples within the scope of the claims, and it is understood that these also naturally fall within the technical scope of the present disclosure. Furthermore, the components in the above embodiments may be combined in any manner as long as it does not deviate from the spirit of the disclosure.

Specific examples of the present disclosure have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and variations of the specific examples given above.

This disclosure is suitable for wireless communication systems.

100, 300 Base station 200 Terminal 101, 201 Receiving unit 102, 202 Demodulation/decoding unit 103 Schedule information extraction unit 104, 204, 304 Allocation control unit 105 Control information generation unit 106, 205 Encoding/modulation unit 107, 206 Transmitting unit 203 Schedule information generation unit 301 Communication quality measurement unit 302 Preamble detection unit 303 Interference classification unit

Claims (10)

A receiving unit that receives schedule information regarding timing for each terminal that is within a communication range to go outside the communication range,
A control unit that assigns the terminals to each channel based on the schedule information;
Equipped with
The control unit sets a group of the terminals based on the schedule information;
The control unit determines the number of terminals to be assigned to each of the channels based on the number of terminals included in the group and the number of channels.
Base station. The group includes terminals whose timing is within a first predetermined time.
The base station according to claim 1 . the schedule information includes information indicating attributes of a means of transportation used by a user who owns the terminal;
The group includes terminals having the same attribute.
The base station according to claim 1 . the schedule information includes information indicating whether the user who owns the terminal desires to use a seat provided in the means of transportation used by the user,
the control unit sets a first group including a terminal owned by a user who desires to use the seat, and a second group including a terminal owned by a user who does not desire to use the seat;
The base station according to claim 1 . The control unit sets the terminal that has transmitted the schedule information and the terminal that has not transmitted the schedule information to different groups.
The base station according to claim 1 . A base station,
A receiving unit that receives schedule information regarding timing for each terminal that is within a communication range to go outside the communication range,
A control unit that assigns the terminals to each channel based on the schedule information;
an interference classification unit that measures interference on each channel and detects an amount of interference from a wireless device that belongs to a network different from a network to which the base station belongs ;
Equipped with
The control unit assigns the terminal to the channel based on the schedule information and the magnitude of the interference amount;
The control unit classifies channels into a first channel having an amount of interference less than a predetermined level and a second channel having an amount of interference equal to or greater than the predetermined level,
the control unit assigns a terminal that exists within the communication range for a time equal to or longer than a second predetermined time to the first channel, and assigns a terminal that exists within the communication range for a time shorter than the second predetermined time to the second channel.
Base station. The control unit assigns a terminal that does not transmit the schedule information to the second channel.
The base station according to claim 6 . A base station,
A receiving unit that receives schedule information regarding timing for each terminal that is within a communication range to go outside the communication range,
A control unit that assigns the terminals to each channel based on the schedule information;
an interference classification unit that measures interference on each channel and detects an amount of interference from a wireless device that belongs to a network different from a network to which the base station belongs;
Equipped with
The control unit assigns the terminal to the channel based on the schedule information and the magnitude of the interference amount;
when the means of transportation of the user who owns the terminal indicated by the schedule information is unavailable, the control unit assigns the terminal to a channel with a smaller amount of interference as the distance to the destination of the user increases.
Base station. A base station,
A receiving unit that receives schedule information regarding timing for each terminal that is within a communication range to go outside the communication range,
A control unit that assigns the terminals to each channel based on the schedule information;
an interference classification unit that measures interference on each channel and detects an amount of interference from a wireless device that belongs to a network different from a network to which the base station belongs;
Equipped with
The control unit assigns the terminal to the channel based on the schedule information and the magnitude of the interference amount;
When the transportation means of the user who owns the terminal indicated by the schedule information is unavailable , the control unit assigns the terminal of the user who is not capable of traveling to the destination of the user by a method other than the transportation means to a channel having a smaller amount of interference than a channel to which the terminal of the user who is capable of traveling to the destination of the user by a method other than the transportation means is assigned.
Base station. The base station
receiving schedule information from each terminal within a communication range regarding the timing of going outside the communication range;
Setting a group of the terminals based on the schedule information;
determining the number of terminals to be assigned to each of the channels based on the number of terminals included in the group and the number of channels;
Control methods.

Images