JP2024132496A - COMMUNICATION DEVICE, COMMUNICATION SYSTEM, AND COMMUNICATION METHOD - Google Patents

Abstract

[Problem] To provide a communication device, communication system, and communication method capable of appropriately allocating resources according to communication conditions. [Solution] A communication device according to an embodiment includes a base station that performs wireless communication and a resource allocation device connected to the base station. The resource allocation device receives a resource allocation request for data transmission from the base station, calculates the number of communication blocks required for data transmission from the amount of data transmitted and the reception quality of the downlink channel, selects one resource allocation algorithm from multiple resource allocation algorithms according to the number of communication blocks, allocates resources for data transmission based on the one resource allocation algorithm, and notifies the base station of the resources. [Selected Figure] Figure 13

Description

Embodiments of the present invention relate to a communication device, a communication system, and a communication method.

In a wireless communication system, many terminals communicate data simultaneously. The wireless communication system includes a resource allocation device that allocates resources for communication to the terminals. The resource allocation device allocates resources to multiple terminals that wish to communicate data. Each terminal communicates data using the allocated resources.

The amount of data that multiple terminals wish to communicate varies from terminal to terminal. The frequency with which data is generated also varies from terminal to terminal. Resource allocation devices are required to allocate resources taking these conditions into account.

JP 2022-36772 A

The object of the present invention is to provide a communication device, a communication system, and a communication method that can appropriately allocate resources according to the communication situation.

A communication device according to an embodiment includes a base station that performs wireless communication with a terminal, and a resource allocation device connected to the base station. The resource allocation device receives a resource allocation request for data transmission to the terminal from the base station, calculates the number of communication blocks required for the data transmission from the amount of data transmitted and the reception quality of the downlink channel to the terminal, selects one resource allocation algorithm from among multiple resource allocation algorithms according to the number of communication blocks, allocates resources for the data transmission based on the one resource allocation algorithm, and notifies the base station of the resources.

FIG. 1 is a diagram for explaining an example of a communication system according to an embodiment. FIG. 2 is a diagram for explaining an example of a control device according to the embodiment; 4A and 4B are diagrams for explaining an example of a first allocation determination unit and a second allocation determination unit according to the embodiment. FIG. 2 is a diagram for explaining an example of a frame structure of a modulated signal in a fifth generation mobile communication system. FIG. 2 is a diagram for explaining a first arrangement example of resource blocks according to the embodiment. FIG. 11 is a diagram for explaining a second example of arrangement of resource blocks according to the embodiment. FIG. 13 is a diagram for explaining a third example of arrangement of resource blocks according to the embodiment. 1A and 1B are diagrams for explaining an example of a resource block configuration and an example of minislot allocation according to an embodiment. FIG. 13 is a diagram for explaining an example of the number of resource blocks in a resource block group. FIG. 13 is a diagram for explaining an example of resource allocation of Type 0; FIG. 13 is a diagram for explaining an example of allocation according to an embodiment in a case where each terminal uses only one subband. FIG. 1 is a diagram for explaining an example of CQI and transmission efficiency. 11 is a diagram for explaining an example of allocation according to an embodiment when each terminal uses multiple subbands. FIG. FIG. 4 is a diagram for explaining an example of the number of communication blocks required for transmission according to the embodiment. FIG. 13 is a diagram for explaining a second example of estimation of whether a terminal uses multiple subbands according to the embodiment. FIG. 4 is a diagram for explaining the timing of an allocation process according to the embodiment. FIG. 4 is a diagram for explaining a first setting example of a first time and a second time. FIG. 11 is a diagram for explaining a second setting example of the first time and the second time. 5 is a flowchart for explaining an example of processing by the control device according to the embodiment. 5 is a flowchart for explaining an example of processing by the control device according to the embodiment. FIG. 4 is a diagram for explaining an example of a description format of allocation information according to the embodiment. FIG. 4 is a diagram for explaining an example of a format of allocation information according to the embodiment. FIG. 13 is a diagram for explaining an example of a communication system according to a first modified example. FIG. 11 is a diagram for explaining an example of a communication system according to a second modified example. FIG. 13 is a diagram for explaining an example of a communication system according to a third modified example. FIG. 13 is a diagram for explaining an example of a communication system according to a fourth modified example. FIG. 13 is a diagram for explaining an example of a communication system according to a fifth modified example. FIG. 13 is a diagram for explaining a modified example of the configuration of the allocation determination device. FIG. 13 is a diagram for explaining another modified example of the configuration of the allocation determination device.

The following describes the embodiments with reference to the drawings. The following description is an example of an apparatus and method for embodying the technical idea of the embodiment, and the technical idea of the embodiment is not limited to the structure, shape, arrangement, material, etc. of the components described below. Modifications that a person skilled in the art can easily conceive are naturally included in the scope of the disclosure. In order to make the description clearer, the size, thickness, planar dimensions, or shape of each element may be changed from the actual embodiment and shown diagrammatically. Elements having different dimensional relationships or ratios may be included in multiple drawings. In multiple drawings, corresponding elements may be given the same reference numerals and duplicated descriptions may be omitted. Some elements may be given multiple names, but these examples of names are merely examples and do not deny the use of other names for these elements. Furthermore, elements that do not have multiple names may be given other names. In the following description, "connection" may include not only direct connection but also connection via other elements.

The communication system may be a wireless LAN conforming to the IEEE 802.11 standard, a third generation mobile communication system (3G system), a fourth generation mobile communication system (4G system or LTE-Advanced), or a fifth generation mobile communication system (5G system) that are standardized in the Third Generation Partnership Project (3GPP) (registered trademark). A 5G mobile communication system will be described as the communication system 10 of the embodiment. A sixth generation mobile communication system (6G system) that is being considered for standardization in 3GPP may also be used as the communication system 10.

The 5G system is expected to accommodate a wide variety of services with diverse requirements, including high speed and large capacity, low latency, multiple simultaneous connections, high reliability, and fairness. In order to meet these diverse requirements, efficient resource utilization will be important.

The resource is at least one of frequency, time, space (MIMO), power, code, and orbital angular momentum. The communication system includes an allocation device that allocates resources to terminals. The allocation device is required to perform the resource allocation process in a very short time.

In the 5G system, wireless communication is performed between terminals and base stations using modulated signals modulated by orthogonal frequency division multiplexing (OFDM). The modulated signals used in the 5G system employ mixed-numerology, and are signals that allow for changeable subcarrier spacing. The 5G system defines a unit called a slot, which includes a predetermined number (e.g., 14) of OFDM symbols. Therefore, the modulated signals of the 5G system, which employ mixed-numerology, allow for changeable slot time length.

The 5G system defines a unit called a resource element (RE). A resource element is composed of one subcarrier and one OFDM symbol. Each of the multiple resource elements is specified by a subcarrier position and a symbol position. The subcarrier position indicates the position in the frequency direction in the modulated signal. The symbol position indicates the position in the time direction in the modulated signal. Multiple resource elements (e.g., 12 subcarriers x 14 OFDM symbols = 168 resource elements) make up one resource block (RB). The 5G system also defines a unit called a resource block group (RBG), which is a bundle of multiple resource blocks.

The 5G system uses the Massive MIMO (Multiple-Input and Multiple-Output) system. In the Massive MIMO system, multiple antennas are used for both transmission and reception.

FIG. 1 is a diagram illustrating an example of a communication system 10 according to an embodiment. The communication system 10 includes a core network 30, a base station 40, and an allocation determination device 50. FIG. 1 illustrates a communication system 10 including a single base station 40. The communication system 10 may include multiple base stations 40.

The core network 30 is a backbone communication network in the 5G system. The core network 30 relays packet communications between the base station 40 and other networks, or between multiple base stations 40.

The base station 40 accommodates at least one terminal 20-1, 20-2, ..., 20-n. n is a positive integer equal to or greater than 1. At least one terminal 20-1, 20-2, ..., 20-n is connected to the base station 40. When the terminals 20-1, 20-2, ..., 20-n are not differentiated from one another, each of the terminals 20-1, 20-2, ..., 20-n is referred to as a terminal 20.

The terminal 20 may be an information processing device having a wireless communication function. The terminal 20 includes an antenna. A unique identification number is assigned to the terminal 20. The terminal 20 transmits and receives modulated signals defined by the 5G system to and from the base station 40 via wireless communication. The terminal 20 is owned by a user. The terminal 20 may be portable by the user, or may be installed in a specific location.

The base station 40 includes a communication device 42 and a control device 44. The communication device 42 is connected to the terminal 20 and the core network 30. The communication device 42 may be connected to the core network 30 via a signal line.

The base station 40 transmits and receives modulated signals conforming to the 5G standard via wireless communication with at least one terminal 20. The base station 40 relays packet communication between at least one terminal 20 and the core network 30.

The communication device 42 transmits and receives 5G modulated signals to and from at least one terminal 20 via wireless communication under the control of the control device 44. The communication device 42 includes an antenna. The communication device 42 includes a buffer 46 that stores data to be transmitted to each terminal 20.

The control device 44 is connected to the allocation determination device 50. The control device 44 controls the transmission and reception of modulated signals in at least one terminal 20 and the communication device 42. The control device 44 causes the allocation determination device 50 to execute an allocation process for allocating resources to at least one terminal 20. Here, the resource allocation unit (smallest unit) is referred to as at least one communication block included in the modulated signal. The at least one communication block is identified by its position in the frequency direction and its position in the time direction in the modulated signal. The communication block may be a resource block group, a resource block, or a resource element, or a bundle of multiple resource elements. The terminal 20 transmits and receives data using the allocated communication block.

The allocation determination device 50 may assign a resource block group (in other words, the resource block group is the communication block), or may assign a resource block (in other words, the resource block is the communication block), or may assign any resource element within a resource block (in other words, the resource element is the communication block) to the terminal 20.

The allocation determination device 50 located near the base station 40 is also called a Mobile Edge Computing (MEC) server. The allocation determination device 50 may be located within the base station 40. The allocation determination device 50 may be connected to the core network 30. The allocation determination device 50 connected to the core network 30 is also called a remote server. The allocation determination device 50 is connected to the control device 44.

In the allocation process, the allocation determination device 50 may specify a subcarrier spacing for at least one communication block included in the modulated signal. In the allocation process, the allocation determination device 50 may specify an orthogonal modulation method, a transmission power, or a coding rate for data included in at least one communication block. In the allocation process, the allocation determination device 50 may specify a propagation channel matrix used in a massive MIMO method to a terminal. In addition, the allocation determination device may determine an OAM (Orbital Angular Momentum) mode.

The control device 44 outputs an allocation request to the allocation determination device 50 before performing the allocation process. In a wireless system, resource allocation needs to be performed within a predetermined fixed time. An example of the fixed time is one slot, which is the smallest unit of scheduling (allocation process) time. The fixed time may be expressed as time. The allocation determination device 50 outputs allocation information indicating the resource allocation result to the control device 44 within one slot time after receiving the allocation request. The allocation determination device 50 may set the upper limit of the execution time of the allocation process to one slot time. The fixed time may be multiple slots.

The allocation determination device 50 includes two allocation determination units (a first allocation determination unit 52 and a second allocation determination unit 54). The first allocation determination unit 52 and the second allocation determination unit 54 are based on algorithms having different search ranges. The search range of the algorithm of the first allocation determination unit 52 is wider than that of the second allocation determination unit 54. For this reason, the calculation time for obtaining the first allocation result becomes longer, and the final first allocation result may not be obtained within one slot time. In this case, there is no solution output as the first allocation result. The first allocation determination unit 52 may perform a full search of all possible combinations of allocation results. The first allocation determination unit 52 may obtain the allocation result using machine learning. The first allocation determination unit 52 may obtain the allocation result using quantum computing or the like. The second allocation determination unit 54 sequentially allocates resources to each terminal 20. In this case, since it is not a combinatorial problem, an allocation that satisfies some constraints is performed. However, if a resource with a high rating is assigned to a terminal that performs allocation first, the terminal that performs allocation later has no choice and can only be assigned resources with a low rating. Therefore, the allocation results of all terminals 20 may be low. The order of terminals 20 to which the second allocation determination unit 54 assigns resources may be determined based on the order of the identification information of the terminals 20, the amount of data transmitted in the past, channel usage status, delay requests, the amount of data transmitted in the buffer, etc.

The control device 44 selects the first allocation determination unit 52 or the second allocation determination unit 54 based on information described below, and transmits an allocation request to the selected first allocation determination unit 52 or second allocation determination unit 54.

The control device 44 receives allocation information indicating the allocation result from the selected allocation determination unit. The base station 40 notifies the terminal 20 of the allocation information. The terminal 20 communicates with the communication device 42 in accordance with the allocation information. Note that if there is no solution to be output as the first allocation result, the control device 44 does not receive allocation information indicating the allocation result from the selected allocation determination unit.

Figure 2 is a diagram for explaining an example of the control device 44. The control device 44 includes a CPU 60, a storage 62, a memory 64, and a server I/F unit 70. The storage 62 stores an application executed by the CPU 60. An example of an application is a resource allocation program 74. Examples of the storage 62 are a hard disk and an SSD. The CPU 60 reads the application from the storage 62, writes the application to the memory 64, and executes the application stored in the memory 64. Examples of the memory 64 are DRAM and SRAM. The CPU 60 functions as a resource allocation module 72 by executing the resource allocation program 74. The server I/F unit 70 communicates with the allocation determination device 50. The control device 44 may be configured with a circuit such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array).

Figure 3 is a diagram for explaining an example of the first allocation determination unit 52 and the second allocation determination unit 54. Each of the first allocation determination unit 52 and the second allocation determination unit 54 includes a CPU 80, a storage 82, a memory 84, and a base station I/F unit 86. The storage 82 stores an application executed by the CPU 80. An example of the application is an allocation determination program 90. Examples of the storage 82 are a hard disk and an SSD. The CPU 80 reads the application from the storage 82, writes the application to the memory 84, and executes the application stored in the memory 84. Examples of the memory 84 are DRAM and SRAM. The CPU 80 functions as an allocation determination module 88 by executing the allocation determination program 90. The base station I/F unit 86 communicates with the control device 44. The first allocation determination unit 52 and the second allocation determination unit 54 may be configured with a circuit such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array).

Figure 4 is a diagram illustrating an example of the frame structure of a 5G modulated signal.

The 5G system defines frames of a predetermined length. The length of a frame is 10 ms. One frame includes 10 subframes, each of a predetermined length. The length of a subframe is 1 ms.

The 5G system defines five subcarrier spacings: 15 kHz (μ=0), 30 kHz (μ=1), 60 kHz (μ=2), 120 kHz (μ=3), and 240 kHz (μ=5). μ is a value that identifies the subcarrier spacing.

The 5G system defines a unit called a slot. A slot is composed of 14 OFDM symbols. The time length of an OFDM symbol varies depending on the subcarrier spacing. Therefore, the time length of a slot varies depending on the subcarrier spacing.

A subframe contains at least one slot. If the subcarrier spacing is set to 15 kHz, a subframe contains one slot. If the subcarrier spacing is set to 30 kHz, a subframe contains two slots. If the subcarrier spacing is set to 60 kHz, a subframe contains four slots. If the subcarrier spacing is set to 120 kHz, a subframe contains eight slots. If the subcarrier spacing is set to 240 kHz, a subframe contains 16 slots.

The narrower the subcarrier spacing, the longer the slot time length, which is more resistant to multipath but has a larger delay. For example, when the subcarrier spacing is 15 kHz, the slot time length is 1 ms, which is more resistant to multipath but has a larger delay. The wider the subcarrier spacing, the shorter the slot time length is, which is less resistant to multipath but has a larger delay, but is more susceptible to ISI (Inter Symbol Interference). For example, when the subcarrier spacing is 240 kHz, the slot time length is 0.0625 ms, which is less resistant to multipath but has a larger delay.

When the terminal 20 is moving at a low speed and transmitting data with a large allowable delay time, the control device 44 may assign a resource block with a narrow subcarrier spacing to the terminal 20. The control device 44 may assign resource elements included in the resource block with a narrow subcarrier spacing to the terminal 20.

When the terminal 20 is moving at high speed and transmits and receives data with a short allowable delay time, the control device 44 may assign a resource block with a wide subcarrier spacing to the terminal 20. The control device 44 may assign resource elements included in the resource block with a wide subcarrier spacing to the terminal 20.

This allows the 5G system to use wider subcarriers and shorter slot times than the 4G system.

Figure 5 is a diagram for explaining a first example of resource block (RB) arrangement. A resource block is composed of one slot (14 OFDM symbols) in the time direction and a certain number of subcarriers (e.g., 12) in the frequency direction.

In a 5G modulated signal, multiple resource blocks are grouped into one resource block group. For example, in a 5G modulated signal, when using a 100 MHz band, one subframe contains 17 resource block groups.

For example, if one subframe contains 16 resource blocks, the 16 resource blocks are composed of one slot (14 OFDM symbols) and 192 (12 x 16) subcarriers.

The control device 44 may assign the widest subcarrier spacing of 15 kHz (μ=0) to the subcarrier spacing of resource blocks in all regions of the band, as shown in FIG. 5. In this case, the control device 44 can cause all terminals 20 to transmit and receive data with a large allowable delay time but with high resistance to multipath.

Figure 6 is a diagram for explaining a second example of resource block (RB) arrangement. As shown in Figure 6, the control device 44 may assign the narrowest subcarrier spacing of 240 kHz (μ = 4) to the subcarrier spacing of resource blocks in all regions of the band. In this case, the control device 44 can cause at least one terminal 20 to transmit and receive data with a short allowable delay time.

Figure 7 is a diagram for explaining a third example of resource block (RB) arrangement. As shown in Figure 7, the control device 44 may divide the band into two regions, assign the widest subcarrier spacing of 15 kHz (μ = 0) to the resource blocks in one region, and assign a subcarrier spacing of 60 kHz (μ = 2) to the resource blocks in the other region. In this case, the control device 44 can transmit and receive data by mixing terminals 20 that transmit and receive data with a large allowable delay time but high quality and terminals 20 that do not require high quality but short allowable delay time within a subframe.

The control device 44 can divide the band into multiple regions in this way and assign different subcarrier spacing to each of the resource blocks in the multiple regions. This allows the control device 44 to assign resource blocks with appropriate subcarrier spacing to each terminal 20, thereby satisfying the requirements of each terminal 20.

Figure 8 is a diagram explaining an example of the configuration of a resource block and an example of minislot allocation.

One resource block, for example, includes 14 OFDM symbols in the time direction and 12 subcarriers in the frequency direction. One resource block includes 168 (12 x 14) resource elements. Each of the 168 resource elements can be identified by the subcarrier position and the symbol position.

In the 5G system, a unit called a mini-slot is defined. A mini-slot is composed of H consecutive OFDM symbols and one subcarrier, where H is an integer equal to or greater than 2, for example, 2, 4, 7, or 14. The control device 44 can assign any resource element in a resource block to the terminal 20 in units of mini-slots.

For example, the control device 44 can assign resource elements to terminals in minislot units and assign the narrowest subcarrier spacing of 240 kHz (μ=4) to the subcarrier spacing of a resource block including a minislot, thereby allowing the terminal 20 to which the resource elements are assigned to transmit and receive data requiring ultra-low latency.

As described above, the base station 40 notifies the terminal 20 of the allocation information. In 5G, the base station 40 notifies the terminal 20 of the allocation information using Downlink Control Information (DCI) included in the Physical Downlink Control Channel (PDCCH) from the base station to the terminal. There are restrictions on the time and frequency positions of communication blocks that can be notified using DCI. The allocation determination device 50 cannot freely allocate communication blocks (time and frequency positions). The communication blocks that the allocation determination device 50 can allocate are communication blocks within the range that can be notified using DCI.

In 5G, two allocation methods, called Type 0 and Type 1, are specified for frequency-direction resource allocation for downlink communication from a base station to a terminal.

In Type 0, resources are allocated in resource block group (RGB) units. FIG. 9 is a diagram for explaining an example of the number of resource blocks (RB) in an RBG. The number of resource blocks in a resource block group varies depending on the bandwidth part (Bandwidth Part Size) and the configuration type. The bandwidth part is the bandwidth of the own group when a certain band, for example, 200 MHz, is divided into 100 MHz bands and a 100 MHz band is allocated to each of the two groups. The configuration type is predetermined by a Radio Resource Control (RRC) message. When the band is fixed, the number of resource block groups changes and the allocated frequency changes.

The DCI specifies a bitmap that indicates the number of the resource block group that transmits data on the Physical Downlink Shared Channel (PDSCH). Based on this bitmap, the terminal (user) can recognize which resource block group transmits data addressed to the terminal, and receive the data transmitted by this resource block group.

In the Type 0 allocation method, resource block group numbers are specified by a bitmap, so the resource block group numbers do not need to be consecutive. Non-consecutive resource block groups can be allocated. This allows for highly flexible resource allocation, for example, allowing only resource block groups with good communication quality to be allocated to terminals. However, specifying resource block group numbers by a bitmap requires a large amount of control information for the designation.

Figure 10 is a diagram for explaining an example of resource allocation of Type 0. One resource block group (RBG) includes four resource blocks (RB). RBG#0 includes RB#32-#35. If the bit value of the bitmap of the frequency allocation section included in the DCI is "1", the resource block group is assigned to the terminal. If the bit value is "0", the resource block group is not assigned. The resource allocation section included in the DCI is a bitmap corresponding to RBG#0 to RBG#7, and if the bitmap of the resource allocation section of terminal 1 (UE1) of user 1 is "01100110" and the bitmap of terminal 2 (UE2) of user 2 is "10011001", RBG#1, RBG#2, RBG#5, and RBG#6 are assigned to UE1, and RBG#0, RBG#3, RBG#4, and RBG#7 are assigned to UE2. The diagonal lines in Figure 10 indicate resource blocks that are not assigned to terminals.

In Type 1, resources are allocated in one or more consecutive resource blocks. The resource allocation region is defined by the starting position of the resource blocks within a particular bandwidth portion and the number of consecutive resource blocks. The starting position of the resource blocks and the number of consecutive resource blocks are converted into a specific single value called the Resource Indication Value (RIV) and notified to the terminal 20.

For time-direction allocation notification, the start position of the ODFM symbol and the number of symbols used for communication are converted into a value called the Start and Length Indication Value (SLIV), and the SLIV is notified. Since one DCI has one allocation in the time direction, when multiple channels are allocated in the frequency direction, the start position of the symbol and the number of symbols used must be the same for all channels.

Due to the DCI format described above, when implementing the Type 0 allocation method, it is possible to allocate non-contiguous resource blocks in the frequency direction. However, it is necessary to allocate continuous resource blocks in the time direction.

As described above, the allocation determination device 50 includes a first allocation determination unit 52 and a second allocation determination unit 54. The algorithm of the first allocation determination unit 52 has a wider search range than the algorithm of the second allocation determination unit 54. The algorithm of the first allocation determination unit 52 is based on exhaustive search, optimization using quantum computing, and simulated branching machines. The algorithm of the second allocation determination unit 54 is based on a local search method.

The control device 44 determines whether to use the first allocation determination unit 52 or the second allocation determination unit 54 depending on the amount of data transmitted from the base station 40 to the terminal 20 and the reception quality for each downlink subband.

In 5G, the terminal 20 measures the reception quality of the downlink channel for each subband and transmits a CQI (Channel Quality Indicator) representing the measurement result to the base station 40. The control device 44 can know the channel quality for each subband based on the CQI. A subband with a high CQI can communicate many communication blocks. When a high-quality subband (a subband with a high CQI) is assigned to the terminal 20, the number of communication blocks required for data communication is small.

The control device 44 may assign multiple subbands to each terminal 20 according to the amount of data stored in the buffer 46 to be transmitted to each terminal. When multiple subbands are assigned to a terminal 20, the number of communication blocks required for data communication is large.

When only one subband is assigned to each terminal, the second allocation determination unit 54 using an allocation algorithm with a narrow search range can obtain a good solution. When multiple subbands are assigned to each terminal, the second allocation determination unit 54 using an allocation algorithm with a narrow search range cannot obtain a good solution. Therefore, when only one subband is assigned to each terminal, the control device 44 may select the second allocation determination unit 54 and send an allocation request to the second allocation determination unit 54. When multiple subbands are assigned to each terminal, the control device 44 may select the first allocation determination unit 52 using an allocation algorithm with a wide search range and send an allocation request to the first allocation determination unit 52. A good solution can be defined as "a small total number of communication blocks used by all terminals," "a short average communication delay time of all terminals (using the earliest communication block possible)," "an early communication completion time of the terminal that completes communication latest," "high transmission efficiency or throughput of all terminals," "a short worst delay time of all terminals," "high fairness between terminals," "high delay achievement rate," etc.

Figure 11 is a diagram for explaining an example of allocation when each terminal uses only one subband. The horizontal axis indicates subbands (frequency direction), and the vertical axis indicates OFDM symbols (time direction). For simplicity of explanation, an example will be explained below in which the first and last OFDM symbols are used for communication of control information, and the remaining 12 OFDM symbols are used for data communication. Terminal UE1 is assigned three OFDM symbols 2-4 in subband #0. Terminal UE5 is assigned eight OFDM symbols 2-9 in subband #4.

When there is little data to be transmitted to each terminal and each terminal uses only one subband, the control device 44 assigns a subband to each terminal using any method. The control device 44 then causes the second assignment determination unit 54 to execute the assignment process, updates the solution using an assignment sum algorithm with a narrow search range, and searches for a good solution. In the 2opt method, which is well known as a local search method, two terminals are selected and an attempt is made to swap the subbands assigned to the two terminals. If the number of communication blocks decreases as a result of the swap, the swap is executed, and if the number of communication blocks does not decrease, the swap is not executed. The other two terminals are selected and the above is repeated within a fixed time. By repeating the process, there is a high possibility that the solution will approach a good solution.

Figure 12 is a diagram for explaining an example of CQI and transmission efficiency. For example, the transmission efficiency of a subband with a CQI of 15 (= 5.5547) is approximately twice the transmission efficiency of a subband with a CQI of 10 (= 2.7305). Transmission efficiency is the number of bits that can be transmitted with one subcarrier. For example, when the CQI is 15, it is 6 bits (64QAM) x rate (948/1024) = 5.5547. When a terminal that used a subband with a CQI of 10 starts using a subband with a CQI of 15 due to subband swapping, the number of communication blocks used is approximately halved. If the number of communication blocks used by the two terminals decreases as a result of subband swapping, swapping is performed, and if it does not decrease, swapping is not performed.

When each terminal uses only one subband, the allocation determination device 50 can obtain a good solution by simply repeating swapping, as is known from the traveling salesman problem. When each terminal uses only one subband in this way, the allocation determination device 50 can reduce computational costs and power consumption by using a local search method that requires less computation. Furthermore, when there is a requirement to obtain a solution within a fixed time, a local search method may be able to obtain a better solution than a wide-range search method.

Figure 13 is a diagram for explaining an example of allocation when each terminal uses multiple subbands. The horizontal axis indicates subbands (frequency direction), and the vertical axis indicates OFDM symbols (time direction). Terminal UE1 is assigned eight OFDM symbols 2-9 in subband #0 and eight OFDM symbols 2-9 in subband #1. Terminal UE9 is assigned four OFDM symbols 2-5 in subband #13.

As shown in FIG. 13, when each terminal uses multiple subbands, if the number of subbands used by the terminal itself is not equal to the number of subbands used by the terminal to be replaced, simple replacement of subbands is not possible. In this case, the allocation determination device 50 cannot directly apply the local search method. Therefore, when each terminal uses multiple subbands, subband replacement is not performed sufficiently, and the improvement effect of repeated subband replacement is small, so a good solution cannot be obtained. In such a case, it is desirable for the control device 44 to use a broader search algorithm, and an allocation request may be sent to the first allocation determination unit 52.

Whether a terminal will use multiple subbands cannot be strictly determined until actual allocation is performed. However, it is possible to estimate whether a terminal will use multiple subbands based on the amount of data to be transmitted to the terminal and the reception quality of the downlink channel of each terminal.

Figure 14 is a diagram for explaining an example of the number of communication blocks required for transmission. Figure 14 shows the target number of communication blocks required for transmission for each subband when transmitting data to each terminal (each user). The horizontal axis shows the subband (frequency direction), and the vertical axis shows the user number (Radio Network Temporary Indicator: RNTI). The control device 44 can calculate the target number of blocks from the amount of data to be transmitted to the terminal and the CQI. The target number of blocks is the number of bits to be transmitted divided by the number of bits that can be sent in one block. However, the number of bits that can be sent in one block is determined by the transmission efficiency and the number of subcarriers included in one block.

When the maximum of the minimum value of the target number of blocks per subband for each terminal is greater than the threshold value (e.g., 12), the control device 44 determines that the terminal uses multiple subbands. Note that the control device 44 may determine the order of processing for each terminal, determine whether or not multiple subbands are used for each terminal, and when it determines that one terminal uses multiple subbands, it may determine that all terminals use multiple subbands.

When the control device 44 receives an allocation request from a terminal 20, it determines whether all terminals will use a single subband or multiple subbands based on the amount of data and the reception quality of the channel, and based on the result of the determination, it determines whether to send the allocation request to the first allocation determination unit 52 or the second allocation determination unit 54 of the allocation determination device 50.

The control device 44 may be connected to an external RIC (RAN Intelligent controller). In that case, the RIC determines whether to use the first allocation determination unit 52 or the second allocation determination unit 54 based on the amount of data and the reception quality of the channel. The RIC notifies the control device 44 of the result of the determination via the ORN-interface.

In an environment where there is no fluctuation in the CQI of the terminal's receiving channel, data of the same data size is generated periodically, and data of a fixed size is transmitted to the terminal, it is assumed that each terminal uses one subband and allocation is performed using a local search method. Furthermore, it is assumed that the size of the data to be transmitted is large, and a single terminal using multiple subbands is additionally connected to base station 40. If the allocation algorithm is not switched, it is expected that there will be almost no change in allocation for terminals other than the one that was added later. However, if the algorithm is switched, it is expected that the allocation will change for all terminals.

Figure 15 is a diagram for explaining a second example of estimation of whether a terminal uses multiple subbands. Figure 15 shows an example of the result of the control device 44 allocating subbands to each terminal based on SINR (Signal to Interference plus Noise Power Ratio), which is an index of wireless communication quality. Terminals UE1, UE2, UE5, UE6, UE8, and UE9 use only one subband, but terminals UE3, UE4, UE7, and UE10 use multiple subbands. In this way, when even one terminal uses multiple subbands, it may be determined that all terminals use multiple subbands.

The first allocation determination unit 52 or the second allocation determination unit 54, to which an allocation request is sent from the control device 44, performs resource allocation. The first allocation determination unit 52 or the second allocation determination unit 54 that has executed resource allocation transmits allocation information indicating the allocation result to the control device 4. The control device 44 transmits the allocation information to the terminal 20. The terminal 20 receives data from the base station 40 using resources based on the allocation information.

Figure 16 is a diagram for explaining the timing of the allocation process. Prior to executing the allocation process, the control device 44 selects a terminal (referred to as an allocation target terminal) that is to be allocated at the first time t1 from at least one terminal 20. The second time t2 is a time after the first time t1. The second time t2 is the time at which the allocation process is started to allocate communication blocks from the second time t2 onwards to the allocation target terminal.

Between the first time t1 and the second time t2, the control device 44 determines which communication block from the second time t2 onward is to be assigned to the assignment target terminal at the first time t1.

The control device 44 transmits an allocation request to the first allocation determination unit 52 or the second allocation determination unit 54, and obtains allocation information from the first allocation determination unit 52 or the second allocation determination unit 54 by the second time t2.

The control device 44 starts resource allocation processing based on the allocation information at the second time t2. From the third time t3 to the fourth time t4 when the resource allocation processing is completed, the control device 44 causes the terminal 20 and the communication device 42 to transmit and receive modulated signals according to the allocation processing result (wireless communication). Alternatively, the control device 44 may start the allocation processing before the second time t2 and cause the terminal 20 and the communication device 42 to transmit and receive modulated signals according to the allocation processing result.

Figure 17 is a diagram illustrating a first setting example of the first time t1 and the second time t2.

The first time t1 and the second time t2 are times that are determined in advance by scheduling. When the control device 44 executes the allocation process for each predetermined number of subframes, the first time t1 is a time before the predetermined number of subframes that are the target of the allocation process. The first time t1 may be the start time of the subframe, or may be a time that is shifted a predetermined time before or after the start time of the subframe. When the control device 44 executes the allocation process for each predetermined number of subframes, the second time t2 may be the start time of the predetermined number of subframes that are the target of the allocation, or may be a time before the start time of the predetermined number of subframes that are the target. The control device 44 may execute the allocation process for each slot. In that case, the difference between the first time t1 and the second time t2 is one slot.

The first time t1 and the second time t2 may be times asynchronous with the subframe. For example, the first time t1 and the second time t2 may be times that are set when a predetermined event occurs. The control device 44 may determine that the first time t1 is the time when a predetermined amount of downlink data or a predetermined amount of reservation requests for transmission and reception allocations are accumulated in the communication device 42.

When the time when a specified event occurs is set as the first time t1, the control device 44 may set the time a specified time after the first time t1 as the second time t2. When the time when a specified event occurs is set as the first time t1, the control device 44 may set the second time t2 to the start time of the subframe immediately after the first time t1, or a time a specified time before the start time of the subframe immediately after the first time t1.

Figure 18 is a diagram illustrating a second setting example of the first time t1 and the second time t2.

The control device 44 can assign resource elements to the terminals 20 that transmit and receive data in units of minislots. In this case, the control device 44 may set the difference between the first time t1 and the second time t2 as the minimum time length of an OFDM symbol. The minimum time length of an OFDM symbol is the time length of an OFDM symbol when the subcarrier spacing is the narrowest, 240 kHz (μ=4).

The control device 44 may change the difference between the first time t1 and the second time t2. The control device 44 may determine the second time t2 according to the allowable delay time of the data transmitted and received by the allocation target terminal. For example, the control device 44 may shorten the difference between the first time t1 and the second time t2 as the allowable delay time is shorter. This allows the control device 44 to transmit and receive data at an earlier time for data with a shorter allowable delay time.

Figures 19 and 20 are flowcharts illustrating an example of processing by the control device 44.

The control device 44 determines a first time t1 and a second time t2 (S102). The first time t1 is the time at which the resource allocation determination process is started. The first time t1 may be a time scheduled in advance. The first time t1 may be the time at which a predetermined event occurs at which the resource allocation is started. The second time t2 is the timing at which the allocation process is started based on the allocation result determined by the resource allocation determination process.

The control device 44 determines whether the current time is the first time t1 (S104).

If the current time is not the first time t1 (S104: NO), the control device 44 executes the determination process of S104 again.

If the current time is the first time t1 (S104: YES), the control device 44 selects at least one terminal 20 to be assigned at the first time t1 (S106). The assignment target terminals 20 at the first time t1 may be all of the at least one terminal 20 wirelessly connected to the base station 40, or may be a part of the at least one terminal 20.

We will explain some examples of allocation target selection.

If the maximum number of terminals 20 that can be assigned in one assignment process is predetermined, the control device 44 may select at least one terminal 20 as the assignment target within a range of numbers not exceeding the maximum number.

If downlink data is stored in the communication device 42 at the first time t1, the control device 44 may preferentially select the terminal 20 to which the downlink data stored in the communication device 42 is to be sent as the allocation target.

If a reservation request for resource allocation is stored in the communication device 42 at the first time t1, the control device 44 may preferentially select the terminal 20 that sent the reservation request stored in the communication device 42 as the allocation target.

If downlink data whose tolerable delay time is equal to or less than a predetermined time is stored in the communication device 42 at the first time t1, the control device 44 may preferentially select the terminal 20 to which the downlink data whose tolerable delay time is equal to or less than the predetermined time is to be sent as an allocation target.

If, at the first time t1, a reservation request for resource allocation for transmitting and receiving data whose tolerable delay time is equal to or less than a predetermined time is stored in the communication device 42, the control device 44 may preferentially select, as an allocation target, a terminal 20 that transmits and receives data whose tolerable delay time is equal to or less than a predetermined time.

The control device 44 determines an allocation range in the modulated signal (S108). The allocation range is a range consisting of a predetermined number of subcarriers and a predetermined number of OFDM symbols at a time after the second time t2. When performing the allocation process for each predetermined number of subframes, the control device 44 may set the allocation range to a range consisting of all subcarriers included in the modulated signal and a plurality of OFDM symbols included in a predetermined number of subframes after the second time t2.

The allocation range may be changed for each allocation process. The control device 44 may change the allocation range depending on the number of allocation target terminals 20. When the allocation targets include terminals 20 that transmit and receive data with an allowable delay time equal to or less than a predetermined time, the control device 44 may set the allocation range to a range that includes a first number of OFDM symbols immediately after the second time t2. When the allocation targets do not include terminals 20 that transmit and receive data with an allowable delay time equal to or less than a predetermined time, the control device 44 may set the allocation range to a range that includes a second number of OFDM symbols greater than the first number immediately after the second time t2. This allows the control device 44 to transmit and receive data with an allowable delay time equal to or less than a predetermined time at an earlier time.

The control device 44 acquires identification information of a communication block that has already been assigned to the terminal 20 that transmits and receives data included in the allocation range (S110). When a resource block or resource element is selected as the communication block, the control device 44 acquires identification information of a resource block that has already been assigned to the terminal 20 that transmits and receives data included in the allocation range and identification information of an assigned resource element.

The control device 44 determines at least one communication block, excluding the assigned communication block, included in the allocation range as an allocatable communication block (S112). When a resource block or a resource element is selected as the communication block, the control device 44 determines at least one resource block, excluding the assigned resource block, included in the allocation range as an allocatable resource block, and determines at least one resource element, excluding the assigned resource element, included in the allocation range as an allocatable resource element.

The control device 44 receives the CQI transmitted from the allocation target terminal 20 (S202).

The control device 44 obtains the size of the data to be sent to the allocation target terminal 20 from the buffer 46 (S204).

The control device 44 calculates the target number of communication blocks required to transmit data to the allocation target terminal 20 (S206).

The control device 44 determines whether the minimum number of target blocks per subband is greater than or equal to a threshold value (S208).

When the control device 44 determines that the minimum target number of blocks per subband is equal to or greater than the threshold value (Yes in S208), it determines that the allocation target terminal 20 uses multiple subbands and transmits an allocation request to the first allocation determination unit 52 (S210).

If the control device 44 determines that the minimum value of the target number of blocks per subband is not equal to or greater than the threshold value (No in S208), it determines that the allocation target terminal 20 will use one subband and transmits an allocation request to the second allocation determination unit 54 (S212).

The control device 44 receives allocation information from the first allocation determination unit 52 or the second allocation determination unit 54 (S214).

The control device 44 executes an allocation process based on the allocation information (S216). After that, the control device 44 causes at least one terminal 20 and the communication device 42 to transmit and receive modulated signals in accordance with the allocation process.

By executing the above process, the communication device 42 can transmit and receive data to and from the terminal 20 assigned in the assignment process within the assignment range.

Figure 21 is a diagram illustrating an example of a description format for allocation information.

The allocation information indicates which communication block, e.g., resource block group, included in the allocation range is used by the terminal 20 to which the allocation is to be made to transmit or receive data. A portion of at least one resource block group included in the allocation range may not be allocated to any terminal 20.

An example of allocation information is represented by multiple boxes arranged in a matrix, each representing at least one communication block within the allocation range. One of the row or column positions of the multiple boxes arranged in the matrix is specified by the position of the subcarrier. The other row or column position of the multiple boxes arranged in the matrix is specified by the position of the OFDM symbol. Figure 21 shows a description format when (12 subcarriers x 16) x 14 OFDMs make up one resource block group, and 17 resource block groups are the allocation range.

The allocation information in this descriptive format is the solution to the problem of determining which of the allocation target terminals 20 should be associated with each of the multiple boxes.

The first allocation determination unit 52 and the second allocation determination unit 54 can obtain allocation information by having a machine learning model such as a neural network trained in advance. For example, the designer of the first allocation determination unit 52 and the second allocation determination unit 54 creates a neural network that outputs allocation information when input information including the identification information of the allocation target terminal 20, the identification information of at least one allocatable communication block, and the reference information of the allocation target terminal is given. The designer trains the created neural network based on teacher data including past input information and an ideal solution. By using the machine learning model created in this way, the first allocation determination unit 52 and the second allocation determination unit 54 can generate allocation information based on the identification information of the allocation target terminal 20, the identification information of at least one allocatable communication block, and the reference information of the allocation target terminal.

The first allocation determination unit 52 and the second allocation determination unit 54 can also generate allocation information by solving a QUBO problem in which the objective function is a quadratic function including multiple binary variables. In this case, the quadratic function that is the objective function includes at least one binary variable that has a one-to-one correspondence with the allocation target terminal 20, the number of which corresponds to the number of boxes that make up the matrix. Furthermore, the quadratic function may further include a binary variable that represents a constraint condition.

The designers of the first allocation determination unit 52 and the second allocation determination unit 54 create a quadratic function whose solution, when minimized, gives allocation information closer to the preset conditions, based on the identification information of the allocation target terminal, the identification information of at least one allocatable communication block, and the reference information of the allocation target terminal.The designers of the first allocation determination unit 52 and the second allocation determination unit 54 create a formulation algorithm that generates such a quadratic function, based on the identification information of the allocation target terminal, the identification information of at least one allocatable communication block, and the reference information of the allocation target terminal.

By using the formulation algorithm created in this manner, the first allocation determination unit 52 and the second allocation determination unit 54 generate a quadratic function, which is an objective function, based on the identification information of the allocation target terminal, the identification information of at least one allocatable communication block, and the reference information of the allocation target terminal. The first allocation determination unit 52 and the second allocation determination unit 54 provide the generated quadratic function to a QUBO solver to calculate a solution to the quadratic function. The first allocation determination unit 52 and the second allocation determination unit 54 generate allocation information based on the solution of the quadratic function calculated by the QUBO solver.

The first allocation determination unit 52 and the second allocation determination unit 54 may generate allocation information by, for example, determining an allocation order for the terminals to be allocated, and associating the terminals with a number of boxes arranged in a matrix according to the determined order. In this case, the first allocation determination unit 52 and the second allocation determination unit 54 may rank the terminals in order of the least amount of data to be transmitted and received, or may rank the terminals in order of the shortest allowable delay time, or may rank the terminals in order of the least amount of data transmitted and received in the past.

The first allocation information generated by the first allocation determination unit 52 and the second allocation information generated by the second allocation determination unit 54 have the same format. Figure 22 is a diagram for explaining an example of the format of the first allocation information generated by the first allocation determination unit 52 or the second allocation information generated by the second allocation determination unit 54. "A" to "H" shown in Figure 22 are information that identifies the user of the terminal 20 to which the resource elements are allocated.

The reference information may include the allowable delay time of the transmission/reception data in the allocation target terminal 20. In this case, the first allocation determination unit 52 and the second allocation determination unit 54 use a machine learning model or a formulation algorithm that generates the first allocation information and the second allocation information so that a terminal with a short allowable delay time is assigned to a resource element where transmission/reception is completed at an earlier time than a terminal with a long allowable delay time. Specifically, the first allocation determination unit 52 and the second allocation determination unit 54 use a machine learning model or a formulation algorithm that generates the first allocation information and the second allocation information so that a terminal with a short allowable delay time is assigned to a resource element of an OFDM symbol that is earlier in time than a terminal with a long allowable delay time. For example, the reference information indicates that the terminal 20 of user A has a shorter allowable delay time for transmitting/receiving data than the terminal 20 of user D. In this case, by using the machine learning model or the formulation algorithm, the first allocation determination unit 52 and the second allocation determination unit 54 can assign a resource block to the terminal 20 of user A that is earlier in time than the resource block assigned to the terminal 20 of user D, as shown in FIG. 22.

The first allocation determination unit 52 and the second allocation determination unit 54 may use a machine learning model or a formulation algorithm to generate allocation information so that more terminals are capable of wireless communication within the allowable delay time.

The reference information may include the amount of data transmitted and received in the past per unit time at the allocation target terminal or the amount of data predicted in the future per unit time. In this case, the first allocation determination unit 52 and the second allocation determination unit 54 may use a machine learning model or a formulation algorithm that generates allocation information so that more terminals satisfy the amount of data transmitted and received per unit time. In this case, the first allocation determination unit 52 and the second allocation determination unit 54 may use a machine learning model or a formulation algorithm that generates allocation information so that the amount of data transmitted and received per unit time per unit time per terminal in the past or the amount of data predicted in the future exceeds a threshold value is satisfied. The first allocation determination unit 52 and the second allocation determination unit 54 may use a machine learning model or a formulation algorithm that generates allocation information so that the amount of data transmitted and received per unit time per unit time is maximized for all terminals.

The reference information may include the communication quality of data previously transmitted and received at the allocation target terminal. In this case, the first allocation determination unit 52 and the second allocation determination unit 54 may use a machine learning model or a formulation algorithm that generates the allocation information so as to assign a higher coding rate or a higher orthogonal modulation method to a terminal having high communication quality of data previously transmitted and received, compared to a terminal having low communication quality.

Specifically, the first allocation determination unit 52 and the second allocation determination unit 54 use a machine learning model or a formulation algorithm that generates allocation information so as to allocate resource elements contained in resource blocks with wider subcarrier spacing than resource blocks allocated to terminals with lower communication quality to terminals with higher communication quality of data transmitted and received in the past. For example, it is assumed that the reference information indicates that the terminal 20 of user C has higher communication quality than the terminal 20 of user B. In this case, by using the machine learning model or the formulation algorithm, the first allocation determination unit 52 and the second allocation determination unit 54 can allocate a greater number of subcarriers to the terminal 20 of user C than the number of subcarriers allocated to the terminal 20 of user B, as shown in FIG. 22.

Below, we will explain modified examples of the communication system regarding the placement of the allocation determination device 50.

Figure 23 is a diagram for explaining an example of a communication system 10a according to a first modified example. The communication system 10a includes base stations 40a and 40b. A terminal 20a is connected to the base station 40a. A terminal 20b is connected to the base station 40b. An allocation determination device 202 is connected to the base stations 40a and 40b. The allocation determination device 202 corresponds to the allocation determination device (MEC server) 50 shown in Figure 1.

The allocation determination device 202 receives allocation requests from multiple base stations 40a and 40b. In response to receiving an allocation request, the allocation determination device 202 generates allocation information and returns the generated allocation information to the base station 40a or 40b that transmitted the allocation request.

Figure 24 is a diagram for explaining an example of a communication system 10b relating to the second modified example. The communication system 10b includes base stations 40a, 40b, and 40c. The terminal 20a is connected to the base station 40a. The terminal 20b is connected to the base station 40b. The terminal 20c is connected to the base station 40c. The allocation determination device 204 is connected to the core network 30. The allocation determination device 204 corresponds to the allocation determination device 50 shown in Figure 1. The allocation determination device 204 is also referred to as a remote server.

The allocation determination device 204 receives allocation requests from multiple base stations 40a, 40b, and 40c via the core network 30. In response to receiving an allocation request, the allocation determination device 204 generates allocation information and returns the generated allocation information to the base station 40a, 40b, or 40c that sent the allocation request via the core network 30.

Figure 25 is a diagram for explaining an example of a communication system 10c according to the third modified example. The communication system 10c includes a relay device 206. The relay device 206 relays the transmission and reception of information between the base station 40 and the core network 30. The allocation determination device 208 is connected to the relay device 206. The allocation determination device 208 corresponds to the allocation determination device 50 shown in Figure 1. The relay device 206 relays the transmission and reception of information between the base station 40 and the allocation determination device 208. The relay device 206 acquires a part of the reference information of the allocation target terminal required to generate the allocation information from the core network 30. The base station 40 outputs an allocation request to the allocation determination device 208 via the relay device 206. In response to receiving the allocation request, the relay device 206 acquires a part of the information to be included in the reference information of the allocation target terminal from the core network 30, includes the acquired information in the allocation request, and transfers it to the allocation determination device 208. In response to receiving the allocation request, the allocation determination device 208 generates allocation information and returns the generated allocation information to the base station 40 via the relay device 206.

FIG. 26 is a diagram for explaining an example of a communication system 10d according to a fourth modified example. The communication system 10d includes a relay device 212. The relay device 212 relays transmission and reception of information between each of the base stations 40a, 40b and the allocation determination device 214. The base station 40a is connected to the terminal 20a. The base station 40b is connected to the terminal 20b. Each of the base stations 40a, 40b outputs an allocation request to the allocation determination device 214 via the relay device 212. In response to receiving the allocation request, the allocation determination device 214 generates allocation information and returns the generated allocation information to the base stations 40a, 40b that output the allocation request via the relay device 212.

Figure 27 is a diagram for explaining an example of a communication system 10e according to the fifth modified example. The communication system 10e includes a plurality of relay devices 212a, 212b. The communication system 10e includes a plurality of allocation determination devices 214a, 214b that correspond one-to-one to the plurality of relay devices 212a, 212b. The relay device 212a relays the transmission and reception of information between each of the corresponding plurality of base stations 40a, 40b and the corresponding allocation determination device 214a. The relay device 212b relays the transmission and reception of information between each of the corresponding plurality of base stations 40c, 40d and the corresponding allocation determination device 214b. Each of the plurality of base stations 40a, 40b outputs an allocation request to the corresponding allocation determination device 214a via the corresponding relay device 212a. Each of the plurality of base stations 40c, 40d outputs an allocation request to the corresponding allocation determination device 214b via the corresponding relay device 212b. The allocation determination device 214a generates allocation information in response to receiving an allocation request, and returns the generated allocation information to the base stations 40a and 40b that output the allocation request via the corresponding relay device 212a. The allocation determination device 214b generates allocation information in response to receiving an allocation request, and returns the generated allocation information to the base stations 40c and 40d that output the allocation request via the corresponding relay device 212b.

Figure 28 is a diagram for explaining a modified example of the configuration of the allocation determination device 50. In Figure 1, the allocation determination device 50 including two allocation determination units 52, 54 is described. Figure 23 shows an allocation determination device 222 including three allocation determination units 224, 226, 228. The first allocation determination unit 224, the second allocation determination unit 226, and the third allocation determination unit 228 perform different allocation determination processes. The first allocation determination unit 224 obtains a first allocation result. The second allocation determination unit 226 obtains a second allocation result. The third allocation determination unit 228 obtains a third allocation result. The first allocation determination unit 224, the second allocation determination unit 226, and the third allocation determination unit 228 may be implemented as separate devices or may be implemented in the same device.

Figure 29 is a diagram for explaining another modified example of the configuration of the allocation determination device 50. In Figure 1, a common allocation determination device 50 is used for all terminals. Each of the multiple terminals 20 may have different requirements for communication. When the requirements for communication are different, the allocation determination process of the allocation determination device also differs. For example, the multiple terminals 20 may include terminals that wish to perform high-speed, large-capacity communication, terminals that wish to perform low-latency communication, and terminals that wish to enable multiple simultaneous connections. The multiple terminals 20 are classified into multiple terminal groups according to their requirements for communication. An allocation determination device suitable for each terminal group is used.

Three allocation determination devices 230, 240, 250 are connected to a base station 40. A terminal that wishes to perform high-speed, large-capacity communication is called an Enhanced Mobile Broadband (eMBB) terminal. A terminal that wishes to perform low-latency communication is called an Ultra Reliable Low Latency Communication (URLLC) terminal. A terminal that wishes to enable multiple simultaneous connections is called a Massive Machine Type Communication (mMTC) terminal.

The first allocation determination device 230 includes a first allocation determination unit 232 and a second allocation determination unit 234. The first allocation determination unit 232 and the second allocation determination unit 234 perform allocation determination processing in accordance with an allocation policy for eMBB terminals.

The second allocation determination device 240 includes a first allocation determination unit 242 and a second allocation determination unit 244. The first allocation determination unit 242 and the second allocation determination unit 244 perform allocation determination processing in accordance with the allocation policy for the URLLC terminal.

The third allocation determination device 250 includes a first allocation determination unit 252 and a second allocation determination unit 254. The first allocation determination unit 252 and the second allocation determination unit 254 perform allocation determination processing in accordance with an allocation policy for mMTC terminals.

The control device 44 transmits allocation requests to the first allocation determination device 230, the second allocation determination device 240, and the third allocation determination device 250 in a predetermined order.

For example, since URLLC terminals have strict delay time requirements, it is desirable to allocate resources so that all data can be transmitted within the delay time or within one slot. For this reason, the control device 44 may first transmit an allocation request to the second allocation determination device 240. The control device 44 also notifies the second allocation determination device 240 of information necessary for resource allocation, such as the amount of data from the terminal, the allowable delay time, channel information, etc. When the second allocation determination device 240 receives an allocation request from the control device 44, it returns allocation information to the control device 44 before the first fixed time has elapsed.

Examples of resource allocation policies for URLLC terminals that the second allocation determination device 240 follows are: not allocating the last 7 symbols of the 14 OFDM symbols that make up one slot; making the last symbol used as close to the front as possible; and minimizing the average delay time for users of URLLC terminals. Based on this policy, the second allocation determination device 240 may determine the actual allocation using full search, machine learning, a QUBO problem solver, or the like. When the first fixed time is short, the second allocation determination device 240 may change the allocation algorithm, such as narrowing the search range for the optimal solution or using an algorithm that is easier to calculate. When the first fixed time is long, the second allocation determination device 240 may use an algorithm with a wide search range, such as performing a full search for the optimal combination.

The control device 44 may transmit an allocation request to the first allocation determination device 230 after the second allocation determination device 240. The second allocation determination device 240 notifies the first allocation determination device 230 of the communication block information allocated to the URLLC terminal via the control device 44 or directly. The control device 44 also notifies the first allocation determination device 230 of information necessary for resource allocation, such as the terminal data volume, allowable delay time, channel information, etc. The first allocation determination device 230 allocates communication blocks other than the communication blocks allocated to the URLLC terminal to the eMBB terminal. When the first allocation determination device 230 receives an allocation request from the control device 44, it returns the allocation information to the control device 44 before the second fixed time has elapsed.

Examples of resource allocation policies for eMMB terminals that the first allocation determination device 230 follows are round robin, max throughput, and proportional fairness. Based on this policy, the first allocation determination device 230 may determine the actual allocation using full search, machine learning, a solver that solves the QUBO problem, or the like. When the second fixed time is short, the first allocation determination device 230 may use an algorithm with a wide search range, and when the second fixed time is long, may use an algorithm with a wide search range. Since eMBB terminals do not have strict delay requirements, there is no need to transmit all data within the delay time or within one slot, and data may be carried over to the next slot.

The control device 44 may transmit an allocation request to the third allocation determination device 250 after the first allocation determination device 230. The first allocation determination device 230 notifies the third allocation determination device 250 of the communication block information allocated to the eMBB terminal via the control device 44 or directly. The third allocation determination device 250 allocates communication blocks other than the communication blocks allocated to the URLLC terminal and the eMBB terminal to the mMTC terminal. The control device 44 also notifies the third allocation determination device 250 of information necessary for resource allocation, such as the amount of data of the terminal, the allowable delay time, channel information, etc. When the third allocation determination device 250 receives an allocation request from the control device 44, it returns the allocation information to the control device 44 before the third fixed time has elapsed.

The ratio of the first fixed time, the second fixed time, and the third fixed time depends on the number of users in each terminal group, the amount of data, the channel conditions, etc. For example, if the number of users in the first terminal group increases, the first fixed time may be lengthened, and the second fixed time and the third fixed time may be shortened.

The sum of the first fixed time, the second fixed time, and the third fixed time is a time equivalent to the slot length.

Each of the first allocation determination device 230, the second allocation determination device 240, and the third allocation determination device 250 may include three allocation determination units, similar to the allocation determination device 222 shown in FIG. 28.

The order in which the control device 44 transmits allocation requests is not limited to the order of the second allocation determination device 240, the first allocation determination device 230, and the third allocation determination device 250 described above, and may be other orders.

The present invention is not limited to the above-described embodiment as it is, and in the implementation stage, the components can be modified and embodied without departing from the gist of the invention. In addition, various inventions can be formed by appropriately combining the multiple components disclosed in the above-described embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, components from different embodiments may be appropriately combined.

20...Terminal, 30...Core network, 40...Base station, 42...Communication device, 44...Control device, 50...Allocation determination device, 52, 54...Allocation determination unit

Claims (10)

A base station that wirelessly communicates with a terminal;
a resource allocation device connected to the base station,
The resource allocation device,
receiving a resource allocation request for data transmission to the terminal from the base station;
determining a number of communication blocks necessary for the data transmission from the amount of data transmitted and the reception quality of the terminal;
selecting one resource allocation algorithm from among a plurality of resource allocation algorithms according to the number of communication blocks;
allocating resources for the data transmission based on the one resource allocation algorithm;
A communication device that notifies the base station of the resources. The plurality of resource allocation algorithms include:
a first algorithm for a first search range;
and a second algorithm having a second search range narrower than the first search range. The communication device of claim 2, wherein the second algorithm is based on a local search method. The communication device according to claim 1, wherein the resource is at least one of time, frequency, space, power, code, and orbital angular momentum. The communication device according to claim 1, wherein the number of communication blocks required by the resource allocation device is greater the larger the amount of data, and is smaller the higher the reception quality. The communication device according to claim 1, wherein the resource allocation device receives the data amount and the reception quality from the base station. The communication device according to claim 1, wherein the resource allocation device notifies the base station of the resources within a fixed time. The communication device according to claim 7, wherein the resource allocation device limits the execution time of the one resource allocation algorithm according to the fixed time. A communication device according to claim 1;
The base station;
A communication system comprising the terminal. A base station that wirelessly communicates with a terminal;
A communication method for a communication device including a resource allocation device connected to the base station,
receiving a resource allocation request for data transmission to the terminal from the base station;
determining a number of communication blocks necessary for the data transmission from the amount of data transmitted and a reception quality of a downlink channel to the terminal;
selecting one resource allocation algorithm from among a plurality of resource allocation algorithms according to the number of communication blocks;
allocating resources for the data transmission based on the one resource allocation algorithm;
and notifying the base station of the resources.

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