Communication system and communication method

Abstract

To provide a communication device, a communication system, and a communication method, capable of allocating appropriately resources in accordance with communication conditions.SOLUTION: A communication device according to one 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; determines the number of communication blocks required for the data transmission on the basis of an amount of data to be transmitted and a reception quality of a downward channel; selects one resource allocation algorithm from among a plurality of resource allocation algorithms in accordance with the number of communication blocks; and allocates a resource for the data transmission on the basis of the one resource allocation algorithm and notifies the base station of the resources.SELECTED DRAWING: Figure 13

Description

[Technical Field]

[0001] Embodiments of the present invention is communication The present invention relates to a system and a communication method. [Background technology]

[0002] In a wireless communication system, a large number of 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.

[0003] The amount of data that a large number of terminals wish to communicate varies from terminal to terminal. The frequency with which data is generated also varies from terminal to terminal. A resource allocation device is required to allocate resources taking these conditions into consideration. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2022-36772 Summary of the Invention [Problem to be solved by the invention]

[0005] The object of the present invention is to appropriately allocate resources according to communication conditions. Possible communication The present invention provides a system and a method for communication. [Means for solving the problem]

[0006] Communication according to embodiments system performs wireless communication with the terminal a control device included in a base station together with a communication device and controlling the communication device; The aforementioned Control device connected to and allocating resources for data transmission by the communication device to the terminal based on a plurality of resource allocation algorithms, respectively. and a resource allocation device for performing the resource allocation. The control device The amount of data transmitted; On your deviceThe number of communication blocks required for the data transmission is calculated from the reception quality and the number of communication blocks is calculated according to the number of communication blocks. The aforementioned selecting one resource allocation algorithm from among a plurality of resource allocation algorithms; An allocation request for the selected one resource allocation algorithm is transmitted to the resource allocation device. , selected by the control device Based on the one resource allocation algorithm And, allocating resources for said data transmission; The aforementioned assigned Resources mentioned above Control device Notify. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram illustrating an example of a communication system according to an embodiment. [Figure 2] FIG. 2 is a diagram for explaining an example of a control device according to the embodiment. [Figure 3] 3A and 3B are diagrams for explaining an example of a first allocation determination unit and a second allocation determination unit according to the embodiment. [Figure 4] FIG. 2 is a diagram for explaining an example of a frame structure of a modulated signal in a fifth-generation mobile communication system. [Figure 5] FIG. 2 is a diagram for explaining a first example of resource block arrangement according to the embodiment. [Figure 6] FIG. 10 is a diagram for explaining a second example of resource block arrangement according to the embodiment. [Figure 7] FIG. 10 is a diagram for explaining a third example of resource block arrangement according to the embodiment. [Figure 8] 1A and 1B are diagrams for explaining an example of the configuration of a resource block and an example of allocation of minislots according to an embodiment; [Figure 9] FIG. 10 is a diagram illustrating an example of the number of resource blocks in a resource block group. [Figure 10] FIG. 10 is a diagram for explaining an example of Type 0 resource allocation. [Figure 11] FIG. 10 is a diagram for explaining an example of allocation according to an embodiment in which each terminal uses only one subband. [Figure 12] FIG. 10 is a diagram for explaining an example of CQI and transmission efficiency. [Figure 13]FIG. 10 is a diagram for explaining an example of allocation according to an embodiment when each terminal uses multiple subbands. [Figure 14] FIG. 10 is a diagram for explaining an example of the number of communication blocks required for transmission according to the embodiment. [Figure 15] FIG. 10 is a diagram for explaining a second example of estimation of whether a terminal uses multiple subbands according to the embodiment. [Figure 16] FIG. 10 is a diagram for explaining the timing of allocation processing according to the embodiment. [Figure 17] FIG. 4 is a diagram for explaining a first setting example of a first time and a second time. [Figure 18] FIG. 10 is a diagram for explaining a second setting example of the first time and the second time. [Figure 19] 6 is a flowchart illustrating an example of processing by a control device according to the embodiment. [Figure 20] 6 is a flowchart illustrating an example of processing by a control device according to the embodiment. [Figure 21] FIG. 2 is a diagram for explaining an example of a description format of allocation information according to the embodiment. [Figure 22] FIG. 4 is a diagram for explaining an example of a format of allocation information according to the embodiment. [Figure 23] FIG. 10 is a diagram illustrating an example of a communication system according to a first modified example. [Figure 24] FIG. 10 is a diagram illustrating an example of a communication system according to a second modified example. [Figure 25] FIG. 10 is a diagram illustrating an example of a communication system according to a third modified example. [Figure 26] FIG. 10 is a diagram illustrating an example of a communication system according to a fourth modified example. [Figure 27] FIG. 13 is a diagram illustrating an example of a communication system according to a fifth modified example. [Figure 28] FIG. 10 is a diagram for explaining a modified example of the configuration of the allocation determination device. [Figure 29] FIG. 10 is a diagram for explaining another modified example of the configuration of the allocation determination device. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments will be described with reference to the drawings. The following description exemplifies devices and methods for embodying the technical concepts of the embodiments. The technical concepts of the embodiments are not limited to the structures, shapes, arrangements, materials, etc. of the components described below. Modifications that can be easily conceived by those skilled in the art are naturally included within the scope of the disclosure. For clarity of explanation, the drawings may schematically depict elements with different sizes, thicknesses, planar dimensions, shapes, etc., compared to the actual embodiment. Elements with different dimensional relationships or ratios may be included in multiple drawings. Corresponding elements may be designated by the same reference numerals in multiple drawings, and redundant description may be omitted. Some elements may be designated by multiple names, but these names are merely examples and do not necessarily mean that these elements may be designated by other names. Furthermore, elements that do not have multiple names may also be designated by other names. In the following description, "connection" may include not only direct connection but also connection via other elements.

[0009] Examples of communication systems include 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), and a fifth-generation mobile communication system (5G system) standardized by 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 by 3GPP may also be used as the communication system 10.

[0010] The 5G system is expected to accommodate a wide variety of services with diverse requirements, such as high speed, large capacity, low latency, multiple simultaneous connections, high reliability, and fairness. In order to meet these diverse requirements, efficient resource utilization is crucial.

[0011] 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 an extremely short time.

[0012] In the 5G system, wireless communication is performed between a terminal and a base station using a modulated signal modulated by orthogonal frequency division multiplexing (OFDM). The modulated signal used in the 5G system employs a mixed-numerology scheme, and is a signal with variable 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 signal of the 5G system employing the mixed-numerology scheme can change the time length of the slot.

[0013] The 5G system defines a unit called a resource element (RE). A resource element consists of one subcarrier and one OFDM symbol. Each of the multiple resource elements is identified by its subcarrier position and symbol position. The subcarrier position indicates the position in the frequency direction of the modulated signal. The symbol position indicates the position in the time direction of the modulated signal. Multiple resource elements (for example, 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 bundles multiple resource blocks together.

[0014] The 5G system uses the Massive MIMO (Multiple-Input and Multiple-Output) system, which uses multiple antennas for both transmission and reception.

[0015] 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 the communication system 10 including a single base station 40. The communication system 10 may include multiple base stations 40.

[0016] The core network 30 is a backbone communication network in the 5G system. The core network 30 relays packet communication between a base station 40 and another network or packet communication between multiple base stations 40.

[0017] Base station 40 accommodates at least one terminal 20-1, 20-2, ..., 20-n, where n is a positive integer equal to or greater than 1. At least one terminal 20-1, 20-2, ..., 20-n is connected to base station 40. When there is no need to distinguish between terminals 20-1, 20-2, ..., 20-n, each of terminals 20-1, 20-2, ..., 20-n will be referred to as terminal 20.

[0018] 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.

[0019] 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.

[0020] The base station 40 transmits and receives modulated signals conforming to the 5G system via wireless communication with at least one terminal 20. The base station 40 relays packet communication between the at least one terminal 20 and the core network 30.

[0021] 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 also includes a buffer 46 that stores data to be transmitted to each terminal 20.

[0022] The control device 44 is connected to the allocation determination device 50. The control device 44 controls 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 collection of multiple resource elements. The terminal 20 transmits and receives data using the allocated communication block.

[0023] The allocation determination device 50 may assign a resource block group (in other words, the resource block group is the communication block), a resource block (in other words, the resource block is the communication block), or any resource element within a resource block (in other words, the resource element is the communication block) to the terminal 20.

[0024] 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.

[0025] 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 scheme, transmission power, or 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 scheme to a terminal. The allocation determination device may also determine an OAM (Orbital Angular Momentum) mode.

[0026] Before performing the allocation process, the control device 44 outputs an allocation request to the allocation determination device 50. In a wireless system, resource allocation must 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. Note that the fixed time may be multiple slots.

[0027] 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 with different search ranges. The search range of the algorithm of the first allocation determination unit 52 is wider than that of the algorithm of the second allocation determination unit 54. This increases the calculation time required to determine the first allocation result, and the final first allocation result may not be determined within one slot time. In this case, no solution is output as the first allocation result. The first allocation determination unit 52 may perform an exhaustive search of all possible combinations of allocation results. The first allocation determination unit 52 may determine the allocation result using machine learning. The first allocation determination unit 52 may determine 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 certain constraints is performed. However, if a terminal that is assigned resources first is assigned resources with a high evaluation, terminals that are assigned later have no choice and can only be assigned resources with a low evaluation. As a result, the evaluation of the allocation results for all terminals 20 may be low. The order in which the second allocation determination unit 54 assigns resources to terminals 20 may be determined based on the order of the identification information of terminals 20, the amount of data transmitted in the past, channel usage status, delay requirements, the amount of data transmitted in the buffer, etc.

[0028] 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.

[0029] 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.

[0030] FIG. 2 is a diagram illustrating 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 the 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 by a circuit such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array).

[0031] FIG. 3 is a diagram illustrating 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 by circuits such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array).

[0032] FIG. 4 is a diagram illustrating an example of a frame configuration of a modulated signal in the 5G system.

[0033] The 5G system defines frames of a predetermined length. The frame length is 10 ms. One frame includes 10 subframes, each of which has a predetermined length. The subframe length is 1 ms.

[0034] 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), where μ is a value that identifies the subcarrier spacing.

[0035] The 5G system defines a unit called a slot. A slot consists 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.

[0036] One subframe contains at least one slot. If the subcarrier spacing is set to 15 kHz, one subframe contains one slot. If the subcarrier spacing is set to 30 kHz, one subframe contains two slots. If the subcarrier spacing is set to 60 kHz, one subframe contains four slots. If the subcarrier spacing is set to 120 kHz, one subframe contains eight slots. If the subcarrier spacing is set to 240 kHz, one subframe contains 16 slots.

[0037] 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 delay but is more susceptible to the effects of ISI (Inter Symbol Interference). For example, when the subcarrier spacing is 240 kHz, the slot time length is 0.0625 ms, which is less delay but is more susceptible to the effects of ISI.

[0038] When the terminal 20 is moving at a low speed and transmitting and receiving data with a large allowable delay time, the control device 44 may allocate a resource block with a narrow subcarrier spacing to the terminal 20. The control device 44 may allocate resource elements included in the resource block with a narrow subcarrier spacing to the terminal 20.

[0039] When terminal 20 is moving at high speed and transmitting / receiving data with a short allowable delay time, control device 44 may allocate resource blocks with wide subcarrier spacing to terminal 20. Control device 44 may allocate resource elements included in resource blocks with wide subcarrier spacing to terminal 20.

[0040] This allows the 5G system to use wider subcarriers and shorter slot times than the 4G system.

[0041] 5 is a diagram illustrating a first example of resource block (RB) allocation. A resource block is composed of one slot (14 OFDM symbols) in the time direction and a predetermined number of subcarriers (for example, 12) in the frequency direction.

[0042] In a 5G modulation signal, multiple resource blocks are grouped into one resource block group. For example, in a 5G modulation signal using a 100 MHz band, one subframe contains 17 resource block groups.

[0043] For example, if one subframe includes 16 resource blocks, the 16 resource blocks are made up of one slot (14 OFDM symbols) and 192 (12×16) subcarriers.

[0044] The control device 44 may allocate 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 allows all terminals 20 to transmit and receive data that has a large allowable delay time but is resistant to multipath interference.

[0045] Fig. 6 is a diagram illustrating a second example of resource block (RB) allocation. As shown in Fig. 6, the control device 44 may allocate 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.

[0046] 7 is a diagram illustrating a third example of resource block (RB) allocation. As shown in FIG. 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 of one region, and assign the subcarrier spacing of 60 kHz (μ=2) to the resource blocks of 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.

[0047] The control device 44 divides the band into multiple regions in this way and can assign different subcarrier spacings to the resource blocks in each of 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.

[0048] FIG. 8 is a diagram for explaining an example of the configuration of resource blocks and an example of minislot allocation.

[0049] One resource block includes, for example, 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 its subcarrier position and symbol position.

[0050] 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 allocate any resource element in a resource block to the terminal 20 in mini-slot units.

[0051] For example, the control device 44 assigns resource elements to terminals in minislot units and assigns the narrowest subcarrier spacing of 240 kHz (μ=4) to the subcarrier spacing of the resource block including the minislot, thereby allowing the terminal 20 to which the resource elements are assigned to transmit and receive data requiring ultra-low delay.

[0052] 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) transmitted 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 (positions in the time and frequency directions). The communication blocks that the allocation determination device 50 can allocate are communication blocks that fall within the range that can be notified using DCI.

[0053] In 5G, two allocation methods called Type 0 and Type 1 are specified for frequency-direction resource allocation for downlink communications from base stations to terminals.

[0054] In Type 0, resources are allocated in units of resource block groups (RGB). Figure 9 is a diagram illustrating 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 size and configuration type. The bandwidth part is the bandwidth of the group in question when a certain band, for example 200 MHz, is divided into 100 MHz bands and each 100 MHz band is allocated to 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 frequencies also change.

[0055] The DCI specifies a bitmap indicating the numbers of resource block groups that transmit data on the Physical Downlink Shared Channel (PDSCH). Based on this bitmap, a terminal (user) can recognize which resource block group transmits data addressed to it and receive the data transmitted in this resource block group.

[0056] 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.

[0057] FIG. 10 is a diagram illustrating an example of Type 0 resource allocation. One resource block group (RBG) includes four resource blocks (RB). RBG#0 includes RB#32-#35. If the bit value of the bitmap in the frequency allocation section included in the DCI is "1", the resource block group is allocated to the terminal. If the bit value is "0", the resource block group is not allocated. The resource allocation section included in the DCI is a bitmap corresponding to RBG#0 to RBG#7. If the bitmap of the resource allocation section for user 1's terminal 1 (UE1) is "01100110" and the bitmap for user 2's terminal 2 (UE2) is "10011001", RBG#1, RBG#2, RBG#5, and RBG#6 are allocated to UE1, and RBG#0, RBG#3, RBG#4, and RBG#7 are allocated to UE2. The diagonal lines in FIG. 10 indicate resource blocks that are not allocated to terminals.

[0058] In Type 1, resources are allocated to one or more consecutive resource blocks. A resource allocation region is defined by the starting position of the resource blocks within a specific 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 Resource Indication Value (RIV) and notified to terminal 20.

[0059] 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 only 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.

[0060] Due to the DCI format described above, when the Type 0 allocation method is implemented, discontinuous resource blocks can be allocated in the frequency direction, but continuous resource blocks must be allocated in the time direction.

[0061] 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.

[0062] 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.

[0063] In 5G, 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 base station 40. Based on the CQI, control device 44 can know the channel quality for each subband. 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 terminal 20, the number of communication blocks required for data communication is small.

[0064] The control device 44 may allocate multiple subbands to each terminal 20 according to the amount of data to be transmitted to each terminal stored in the buffer 46. When multiple subbands are allocated to a terminal 20, the number of communication blocks required for data communication is large.

[0065] When only one subband is assigned to each terminal, the second allocation determination unit 54, which uses 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, which uses 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, which uses 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 by "a small total number of communication blocks used by all terminals," "a short average communication delay time for all terminals (using the earliest possible communication block)," "a short communication completion time for the terminal that completes communication latest," "high transmission efficiency or throughput for all terminals," "a short worst-case delay time for all terminals," "high fairness between terminals," "a high delay achievement rate," etc.

[0066] Fig. 11 is a diagram illustrating an example of allocation when each terminal uses only one subband. The horizontal axis represents subbands (frequency direction), and the vertical axis represents OFDM symbols (time direction). For simplicity of explanation, the following describes an example 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 allocated three OFDM symbols 2-4 in subband #0. Terminal UE5 is allocated eight OFDM symbols 2-9 in subband #4.

[0067] When the amount of data to be transmitted to each terminal is small and each terminal uses only one subband, the control device 44 allocates subbands to each terminal using an arbitrary method. The control device 44 then causes the second allocation determination unit 54 to perform allocation processing, updating the solution using an allocation sum algorithm with a narrow search range and searching for a good solution. The 2opt method, a well-known local search method, selects two terminals and attempts to swap the subbands allocated to the two terminals. If the number of communication blocks decreases as a result of the swap, the swap is performed; if the number of communication blocks does not decrease, the swap is not performed. Two other terminals are selected and the above process is repeated within a fixed time. By repeating this process, the solution is likely to approach a good solution.

[0068] FIG. 12 is a diagram illustrating 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 per subcarrier. For example, when the CQI is 15, it is 6 bits (64QAM) × rate (948 / 1024) = 5.5547. When a terminal that has been using a subband with a CQI of 10 starts using a subband with a CQI of 15 as a result of subband swapping, the number of communication blocks used is reduced by approximately half. If swapping subbands reduces the number of communication blocks used by the two terminals, swapping is performed; if not, swapping is not performed.

[0069] 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 like this, the allocation determination device 50 can reduce computational costs and power consumption by using a local search method with a low computational load. Furthermore, when a solution is required to be obtained within a fixed time, a local search method may be able to obtain a better solution than a comprehensive search method.

[0070] 13 is a diagram illustrating an example of allocation when each terminal uses multiple subbands. The horizontal axis represents subbands (frequency direction), and the vertical axis represents OFDM symbols (time direction). Terminal UE1 is allocated eight OFDM symbols 2-9 in subband #0 and eight OFDM symbols 2-9 in subband #1. Terminal UE9 is allocated four OFDM symbols 2-5 in subband #13.

[0071] As shown in Figure 13, when each terminal uses multiple subbands, simple subband swapping is not possible unless the number of subbands used by the terminal itself is equal to the number of subbands used by the terminal to which the swapping is to be performed. In this case, the allocation determination device 50 cannot directly apply the local search method. Therefore, when each terminal uses multiple subbands, subband swapping is not performed sufficiently, and the improvement effect of repeated subband swapping is small, making it impossible to obtain a good solution. In such a case, it is desirable for the control device 44 to use a broader search algorithm and may send an allocation request to the first allocation determination unit 52.

[0072] Whether a terminal will use multiple subbands cannot be strictly determined until the actual allocation is performed, but 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.

[0073] Fig. 14 is a diagram illustrating an example of the number of communication blocks required for transmission. Fig. 14 shows, for each subband, the target number of communication blocks required for transmission when transmitting data to each terminal (each user). The horizontal axis represents the subband (frequency direction), and the vertical axis represents the user number (Radio Network Temporarily 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.

[0074] If the maximum value of the minimum value of the target number of blocks per subband for each terminal is greater than a threshold value (for example, 12), the control device 44 determines that the terminal uses multiple subbands. Note that the control device 44 may determine the processing order for each terminal, determine whether or not multiple subbands are to be used for each terminal, and if it determines that one terminal uses multiple subbands, it may also determine that all terminals use multiple subbands.

[0075] 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 determination result, 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.

[0076] The control device 44 may be connected to an external RAN Intelligent controller (RIC). In this 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 determination result via the ORN-interface.

[0077] Assume an environment in which 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, with each terminal using one subband and allocation being performed using a local search method. Furthermore, assume a case in which a terminal that transmits large data size and uses 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.

[0078] Fig. 15 is a diagram for explaining a second example of estimation of whether a terminal will use multiple subbands. Fig. 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.

[0079] The first allocation determination unit 52 or the second allocation determination unit 54, to which an allocation request is transmitted 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.

[0080] 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) to be allocated at a 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.

[0081] Between the first time t1 and the second time t2, the control device 44 determines which communication block from the second time t2 onwards is to be allocated to the allocation target terminal at the first time t1.

[0082] The control device 44 transmits an allocation request to the first allocation determination unit 52 or the second allocation determination unit 54, and acquires allocation information from the first allocation determination unit 52 or the second allocation determination unit 54 by the second time t2.

[0083] The control device 44 starts resource allocation processing based on the allocation information at a second time t2. From a third time t3 to a 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 in accordance with 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 in accordance with the allocation processing result.

[0084] FIG. 17 is a diagram for explaining a first setting example of the first time t1 and the second time t2.

[0085] The first time t1 and the second time t2 are times determined in advance by scheduling. When the control device 44 performs 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 a subframe, or may be a time that is shifted a predetermined amount before or after the start time of a subframe. When the control device 44 performs 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 allocation, or may be a time before the start time of the predetermined number of target subframes. The control device 44 may perform the allocation process for each slot. In this case, the difference between the first time t1 and the second time t2 is one slot.

[0086] 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 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 allocation are accumulated in the communication device 42.

[0087] When the time when a predetermined event occurs is set as the first time t1, the control device 44 may set the second time t2 to a time that is a predetermined time after the first time t1. When the time when a predetermined 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 that is a predetermined time before the start time of the subframe immediately after the first time t1.

[0088] FIG. 18 is a diagram for explaining a second setting example of the first time t1 and the second time t2.

[0089] The control device 44 can allocate resource elements to terminals 20 that transmit and receive data in minislot units. 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).

[0090] 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 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 becomes shorter. In this way, the control device 44 can transmit and receive data at an earlier time as the allowable delay time becomes shorter.

[0091] 19 and 20 are flowcharts for explaining an example of the processing of the control device 44. FIG.

[0092] 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 to start. The first time t1 may be a pre-scheduled time. The first time t1 may be the time at which a predetermined event occurs at which the resource allocation is to start. The second time t2 is the timing at which the allocation process is to start based on the allocation result determined by the resource allocation determination process.

[0093] The control device 44 determines whether the current time is the first time t1 (S104).

[0094] If the current time is not the first time t1 (S104: NO), the control device 44 executes the determination process of S104 again.

[0095] 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 some of the at least one terminal 20.

[0096] Some examples of selection of allocation targets will be described.

[0097] In a case where the maximum number of terminals 20 that can be allocated in one allocation process is predetermined, the control device 44 may select at least one terminal 20 within a range of the number that does not exceed the maximum number as the allocation target.

[0098] At the first time t1, if downlink data is stored in the communication device 42, the control device 44 may preferentially select the terminal 20 to which the downlink data stored in the communication device 42 is to be transmitted as an allocation target.

[0099] 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.

[0100] At the first time t1, if downlink data whose allowable delay time is less than or equal to a predetermined time is stored in the communication device 42, the control device 44 may preferentially select the terminal 20 to which the downlink data whose allowable delay time is less than or equal to the predetermined time is to be sent as the allocation target.

[0101] At a first time t1, if a reservation request for resource allocation for transmitting and receiving data whose allowable 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 a terminal 20 that transmits and receives data whose allowable delay time is equal to or less than a predetermined time as an allocation target.

[0102] 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.

[0103] 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. If 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. If 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.

[0104] The control device 44 acquires identification information of communication blocks that have already been allocated to the terminals 20 that transmit and receive data included in the allocation range (S110). When a resource block or a resource element is selected as the communication block, the control device 44 acquires identification information of resource blocks that have already been allocated to the terminals 20 that transmit and receive data included in the allocation range and identification information of allocated resource elements.

[0105] The control device 44 determines at least one communication block included in the allocation range, excluding the allocated communication blocks, 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 included in the allocation range, excluding the allocated resource blocks, as an allocatable resource block, and determines at least one resource element included in the allocation range, excluding the allocated resource elements, as an allocatable resource element.

[0106] The control device 44 receives the CQI transmitted from the allocation target terminal 20 (S202).

[0107] The control device 44 acquires the size of the data to be transmitted to the allocation target terminal 20 from the buffer 46 (S204).

[0108] The control device 44 calculates the target number of communication blocks required to transmit data to the allocation target terminal 20 (S206).

[0109] The control device 44 determines whether the minimum value of the target number of blocks for each subband is equal to or greater than a threshold value (S208).

[0110] If the control device 44 determines that the minimum value of the 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 will use multiple subbands, and sends an allocation request to the first allocation determination unit 52 (S210).

[0111] 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 sends an allocation request to the second allocation determination unit 54 (S212).

[0112] The control device 44 receives the allocation information from the first allocation determination unit 52 or the second allocation determination unit 54 (S214).

[0113] The control device 44 executes allocation processing based on the allocation information (S216). Thereafter, 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 processing.

[0114] By executing the above process, the communication device 42 can transmit and receive data within the allocation range to and from the terminal 20 assigned in the allocation process.

[0115] FIG. 21 is a diagram illustrating an example of a description format of allocation information.

[0116] The allocation information indicates which communication blocks, e.g., resource block groups, included in the allocation range are used by the terminals 20 to which the allocation is to be made to transmit or receive data. Some of at least one resource block group included in the allocation range may not be allocated to any terminals 20.

[0117] An example of allocation information is represented by a plurality of 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 plurality of boxes arranged in the matrix is ​​specified by the position of a subcarrier. The other of the row or column positions of the plurality of boxes arranged in the matrix is ​​specified by the position of an OFDM symbol. Figure 21 shows a description format in which one resource block group is made up of (12 subcarriers x 16) x 14 OFDMs, and 17 resource block groups are allocated.

[0118] The allocation information in such a description format is a solution to the problem of determining which of the allocation target terminals 20 should be associated with each of the multiple boxes.

[0119] The first allocation determination unit 52 and the second allocation determination unit 54 can obtain allocation information by training a machine learning model such as a neural network 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 identification information of the allocation target terminal 20, identification information of at least one allocatable communication block, and reference information of the allocation target terminal is given. The designer trains the created neural network based on training data including past input information and ideal solutions. 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, identification information of at least one allocatable communication block, and reference information of the allocation target terminal.

[0120] 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 a quadratic function including multiple binary variables is used as an objective function. In this case, the quadratic function, which is the objective function, includes at least one binary variable that corresponds one-to-one to 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.

[0121] The designers of the first allocation determination unit 52 and the second allocation determination unit 54 create a quadratic function whose solution when minimized will obtain allocation information that is closest 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 for generating 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.

[0122] By using the formulation algorithm created in this way, 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.

[0123] The first allocation determination unit 52 and the second allocation determination unit 54 may, for example, determine an allocation order for the terminals to be allocated, and generate allocation information by associating the terminals with a plurality 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 in order of the shortest allowable delay time, or in order of the least amount of data transmitted and received in the past.

[0124] 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. Fig. 22 is a diagram illustrating 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 Fig. 22 are information identifying users of terminals 20 to which resource elements have been allocated.

[0125] The reference information may include an allowable delay time for transmitting and receiving 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 to generate the first allocation information and the second allocation information so that a terminal with a short allowable delay time is assigned to resource elements that complete transmission and reception earlier 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 to generate the first allocation information and the second allocation information so that a terminal with a short allowable delay time is assigned to resource elements of an OFDM symbol that arrives earlier than a terminal with a long allowable delay time. For example, it is assumed that the reference information indicates that the allowable delay time for transmitting and receiving data in the terminal 20 of user A is shorter than that in 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 to the terminal 20 of user A resource blocks that arrive earlier in time than the resource blocks assigned to the terminal 20 of user D, as shown in FIG. 22 .

[0126] 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 are capable of wireless communication within the allowable delay time.

[0127] The reference information may include the amount of data transmitted and received per unit time in the past or the amount of data predicted to be transmitted and received in the future 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 allocation information so that more terminals satisfy the amount of data transmitted and received per unit time. Also, 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 for terminals whose amount of data transmitted and received per unit time in the past or the amount of data predicted to be transmitted and received 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 for all terminals is maximized.

[0128] The reference information may include communication quality of data previously transmitted and received by 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 to generate allocation information so as to assign a higher coding rate or a higher orthogonal modulation scheme to a terminal with high communication quality of data previously transmitted and received than to a terminal with low communication quality.

[0129] 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, to a terminal with high communication quality for data transmitted and received in the past, resource elements included in resource blocks with wider subcarrier spacing than resource blocks allocated to terminals with low communication quality. 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, to the terminal 20 of user C, a number of subcarriers that is greater than the number of subcarriers allocated to the terminal 20 of user B, as shown in FIG. 22 .

[0130] A modification of the communication system regarding the placement of the allocation determination device 50 will be described below.

[0131] 23 is a diagram illustrating 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 FIG.

[0132] Allocation determination device 202 receives allocation requests from multiple base stations 40a, 40b. In response to receiving the allocation requests, allocation determination device 202 generates allocation information and returns the generated allocation information to base station 40a, 40b that transmitted the allocation requests.

[0133] 24 is a diagram illustrating an example of a communication system 10b according to a second modified example. The communication system 10b includes base stations 40a, 40b, and 40c. A terminal 20a is connected to the base station 40a. A terminal 20b is connected to the base station 40b. A terminal 20c is connected to the base station 40c. An 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 FIG. 1. The allocation determination device 204 is also referred to as a remote server.

[0134] 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 the allocation requests, the allocation determination device 204 generates allocation information and returns the generated allocation information via the core network 30 to the base stations 40a, 40b, and 40c that sent the allocation requests.

[0135] FIG. 25 is a diagram illustrating an example of a communication system 10c according to a third modification. The communication system 10c includes a relay device 206. The relay device 206 relays transmission and reception of information between the base station 40 and the core network 30. An 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 FIG. 1. The relay device 206 relays transmission and reception of information between the base station 40 and the allocation determination device 208. The relay device 206 acquires, from the core network 30, a portion of the reference information of the allocation target terminals that is required to generate allocation information. 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, from the core network 30, a portion of the information to be included in the reference information of the allocation target terminals, includes the acquired information in the allocation request, and forwards the allocation request 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 .

[0136] 26 is a diagram illustrating an example of a communication system 10d according to a fourth modification. 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 an 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 requests via the relay device 212.

[0137] 27 is a diagram illustrating an example of a communication system 10e according to a fifth modification. The communication system 10e includes a plurality of relay devices 212a and 212b. The communication system 10e includes a plurality of allocation determination devices 214a and 214b that correspond one-to-one to the plurality of relay devices 212a and 212b. The relay device 212a relays information transmission and reception between each of the plurality of corresponding base stations 40a and 40b and the corresponding allocation determination device 214a. The relay device 212b relays information transmission and reception between each of the plurality of corresponding base stations 40c and 40d and the corresponding allocation determination device 214b. Each of the plurality of base stations 40a and 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 and 40d outputs an allocation request to the corresponding allocation determination device 214b via the corresponding relay device 212b. Allocation determination device 214a generates allocation information in response to receiving an allocation request and returns the generated allocation information to base stations 40a and 40b that output the allocation request via corresponding relay device 212a. Allocation determination device 214b generates allocation information in response to receiving an allocation request and returns the generated allocation information to base stations 40c and 40d that output the allocation request via corresponding relay device 212b.

[0138] FIG. 28 is a diagram illustrating a modified example of the configuration of the allocation determination device 50. In FIG. 1, the allocation determination device 50 including two allocation determination units 52 and 54 has been described. FIG. 23 shows an allocation determination device 222 including three allocation determination units 224, 226, and 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 determines a first allocation result. The second allocation determination unit 226 determines a second allocation result. The third allocation determination unit 228 determines 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.

[0139] FIG. 29 is a diagram illustrating another modified example of the configuration of the allocation determination device 50. In FIG. 1, a common allocation determination device 50 is used for all terminals. Each of the multiple terminals 20 may have different communication requirements. When the communication requirements differ, the allocation determination process of the allocation determination device also differs. For example, the multiple terminals 20 may include terminals that require high-speed, large-capacity communication, terminals that require low-latency communication, and terminals that require multiple simultaneous connections. The multiple terminals 20 are classified into multiple terminal groups according to their communication requirements. An allocation determination device suitable for each terminal group is used.

[0140] Three allocation determination devices 230, 240, and 250 are connected to a base station 40. A terminal that desires high-speed, large-capacity communication is called an Enhanced Mobile Broadband (eMBB) terminal. A terminal that desires low-latency communication is called an Ultra Reliable Low Latency Communication (URLLC) terminal. A terminal that desires to enable multiple simultaneous connections is called a Massive Machine Type Communication (mMTC) terminal.

[0141] 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.

[0142] 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 an allocation policy for URLLC terminals.

[0143] 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.

[0144] 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.

[0145] For example, since URLLC terminals have strict requirements for delay time, it is desirable to allocate resources so that all data can be transmitted within the delay time or within one slot. Therefore, 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. Upon receiving the allocation request from the control device 44, the second allocation determination device 240 returns allocation information to the control device 44 before the first fixed time has elapsed.

[0146] 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; positioning the last symbol used as early 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 exhaustive 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 an exhaustive search for the optimal combination.

[0147] The control device 44 may send 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, either directly or via the control device 44, of information about the communication blocks allocated to URLLC terminals. The control device 44 also notifies the first allocation determination device 230 of information necessary for resource allocation, such as the amount of terminal data, the allowable delay time, channel information, etc. The first allocation determination device 230 allocates communication blocks other than the communication blocks allocated to URLLC terminals to eMBB terminals. Upon receiving an allocation request from the control device 44, the first allocation determination device 230 returns allocation information to the control device 44 before the second fixed time has elapsed.

[0148] Examples of resource allocation policies for eMMB terminals that the first allocation determination device 230 follows include round robin, max throughput, and proportional fairness. Based on this policy, the first allocation determination device 230 may determine the actual allocation using exhaustive search, machine learning, a solver that solves the QUBO problem, or the like. The first allocation determination device 230 may use an algorithm with a wide search range when the second fixed time is short, and may use an algorithm with a wide search range when the second fixed time is long. Since eMBB terminals do not have strict delay requirements, it is not necessary to transmit all data within the delay time or one slot, and data may be carried over to the next slot.

[0149] The control device 44 may send 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 directly or via the control device 44 of information on communication blocks allocated to eMBB terminals. The third allocation determination device 250 allocates communication blocks other than those allocated to URLLC terminals and eMBB terminals to mMTC terminals. The control device 44 also notifies the third allocation determination device 250 of information necessary for resource allocation, such as the amount of terminal data, 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 allocation information to the control device 44 before the third fixed time has elapsed.

[0150] 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.

[0151] The sum of the first fixed time, the second fixed time, and the third fixed time is a time equivalent to the slot length.

[0152] 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.

[0153] The order in which the control device 44 transmits allocation requests is not limited to the above-described order of the second allocation determination device 240, the first allocation determination device 230, and the third allocation determination device 250, but may be other orders.

[0154] The present invention is not limited to the above-described embodiments, and the components can be modified and embodied in practice without departing from the spirit of the invention. Furthermore, various inventions can be created by appropriately combining multiple components disclosed in the above-described embodiments. For example, some components may be omitted from all the components shown in the embodiments. Furthermore, components from different embodiments may be appropriately combined. [Explanation of symbols]

[0155] 20... terminal, 30... core network, 40... base station, 42... communication device, 44... control device, 50... allocation determination device, 52, 54... allocation determination unit

Claims

1. a control device included in the base station together with a communication device that performs wireless communication with a terminal, and that controls the communication device; a resource allocation device connected to the control device and configured to allocate resources for data transmission by the communication device to the terminal based on a plurality of resource allocation algorithms, The control device calculating the number of communication blocks necessary for the data transmission from the data amount of the data transmission and the reception quality of the terminal; selecting one resource allocation algorithm from the plurality of resource allocation algorithms according to the number of communication blocks; sending an allocation request for the selected one of the resource allocation algorithms to the resource allocation device; the resource allocation device, allocating resources for the data transmission based on the one resource allocation algorithm selected by the control device; The communication system notifies the control device of the allocated resources.

2. The plurality of resource allocation algorithms include: a first algorithm for a first search range; a second algorithm having a second search range that is narrower than the first search range.

3. The communication system of claim 2 , wherein the second algorithm is based on a local search method.

4. The communication system of claim 1 , wherein the resource is at least one of time, frequency, space, power, code, and orbital angular momentum.

5. 2. The communication system according to claim 1, wherein the number of communication blocks required by the control device is greater as the amount of data increases and is smaller as the reception quality is higher.

6. A communication system as described in claim 1, wherein the resource allocation device is located near the base station or within the base station.

7. The communication system according to claim 1 , wherein the resource allocation device notifies the control device of the resources within a fixed time.

8. The communication system according to claim 7 , wherein the resource allocation device limits an execution time of the one resource allocation algorithm according to the fixed time.

9. A communication method for a communication system including: a control device included in a base station together with a communication device that performs wireless communication with a terminal, and that controls the communication device; and a resource allocation device connected to the control device, and that allocates resources for data transmission by the communication device to the terminal based on a plurality of resource allocation algorithms, the control device calculates the number of communication blocks necessary for the data transmission from the data amount of the data transmission and the reception quality of the terminal, selects one resource allocation algorithm from the plurality of resource allocation algorithms according to the number of communication blocks, and transmits an allocation request for the selected one resource allocation algorithm to the resource allocation device; A communication method, wherein the resource allocation device allocates resources for the data transmission based on the one resource allocation algorithm selected by the control device, and notifies the control device of the allocated resources.

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