Wireless communication system

Abstract

The wireless communication system includes multiple base stations and multiple M2M devices, and sets multiple tracking zones. The M2M devices include fixed, battery-powered fixed M2M devices (e.g., fixed terminals). Multiple base stations are configured such that the tracking zones include areas fixed to multiple cells where wireless communication between the fixed M2M devices and the fixed M2M devices is possible. The fixed M2M devices or base stations are configured such that, through machine learning of communication frequencies, dedicated cells with communication frequencies higher than other cells are determined, and wireless communication between these dedicated cells and the fixed M2M devices is fixed. Therefore, even when fixed, battery-powered M2M devices are specifically placed in tracking zones where base stations are dispersed, the shortening of the M2M device's battery life can be effectively suppressed.

Description

Technical Field

[0001] The present invention relates to a wireless communication system comprising multiple base stations and multiple M2M (Machine to Machine) devices, and particularly to a wireless communication system that enables good communication with base stations when the M2M devices include devices fixed in a predetermined location and powered by batteries. Background Technology

[0002] In a cell-based mobile communication system, multiple base stations are configured within the communication service area. The communication areas of each base station constitute multiple cells, and these cells form a network within the communication service area. When a user device (UE) such as a portable terminal moves within the communication service area, it selects a cell and communicates with the base station located in that cell.

[0003] Furthermore, when the UE moves within the communication service area, it reselects a suitable cell for communication. The UE performs cell search not only during such movement, but also during startup, standby, and intermittent reception during communication, to detect cells that provide good communication quality for the local station.

[0004] In addition, in recent years, not only has person-to-person communication using portable terminals been gaining attention, but also machine-to-machine (M2M) communication between devices via wired or wireless means without human intervention. Such M2M devices, like portable terminals, can also connect to cellular mobile communication systems in a communicative manner. Among M2M devices, there are those that can move within the communication service area, like portable terminals, and those that are fixed in designated locations. For ease of explanation, the former will be referred to as "mobile M2M devices," and the latter as "fixed M2M devices."

[0005] As an example of a fixed M2M device's configuration, a setting where tracking areas are distributed to base stations can be considered. In such a situation, the fixed M2M device is located in distributed cells. The fixed M2M device uses cell search to detect cells that can provide wireless communication with particularly good quality even among distributed cells, and selects or reselects those cells. For ease of explanation, the cell selection or cell reselection performed by the UE, including the fixed M2M device, will be collectively referred to as cell selection processing.

[0006] As an example of such cell selection processing performed by a fixed M2M device, the wireless communication system disclosed in Patent Document 1 can be cited. In this wireless communication system, cells are ranked based on the relationship between the coverage levels that can be accessed. According to this ranking criterion, any first cell and second cell are ranked, and it is evaluated whether the wireless device should perform a cell change from the first cell to the second cell.

[0007] In Patent Document 1, a typical mobile user device (UE) is mainly exemplified as a wireless device, but an M2M device is also exemplified. The M2M devices exemplified in Patent Document 1 include "mobile M2M devices" such as those included in vehicles, and also include "fixed M2M devices" such as power meters, industrial machinery, or household or personal electrical products.

[0008] Existing technical documents

[0009] Patent documents

[0010] Patent Document 1: Japanese Patent Publication No. 2019-535159 Summary of the Invention

[0011] The problem the invention aims to solve

[0012] Here, when the fixed M2M device is a device powered by a built-in battery, when the fixed M2M device is set in a tracking area where base stations are dispersed, there is a situation where the current consumption increases excessively, resulting in a shorter battery life, as has been determined by the researchers of the present invention.

[0013] In tracking areas where base stations are dispersed, fixed M2M devices are positioned in locations where better wireless communication is possible, as described above. However, when communication conditions, such as cell receiver sensitivity or traffic volume, change due to the surrounding environment, cell search and cell selection processes frequently occur in fixed M2M devices. This is especially true in battery-powered fixed M2M devices, where intermittent operation is common to maximize battery life. Therefore, if communication conditions change during the device's standby period, cell search and cell selection processes are more likely to occur. Consequently, unnecessary power consumption occurs in fixed M2M devices, resulting in shorter battery life.

[0014] The present invention was made to solve the problem of short-lived battery life of M2M devices, even when the battery-powered M2M devices are fixed in a designated location and specifically located in a tracking area where base stations are dispersed.

[0015] Solution for solving the problem

[0016] To address the aforementioned problem, the wireless communication system disclosed herein has the following structure: it includes multiple base stations with at least one cell configured and multiple M2M (Machine to Machine) devices capable of wireless communication with the base stations, and multiple tracking zones are defined. Among the M2M devices, there are fixed M2M devices that are permanently installed and powered by batteries. The multiple base stations are configured such that the tracking zones include areas permanently installed at locations where the multiple cells and the fixed M2M devices can wirelessly communicate. The fixed M2M devices or base stations include fixed M2M devices or base stations configured such that dedicated cells are determined by performing machine learning on the communication frequencies between the multiple cells and the fixed M2M devices, and the wireless communication between the dedicated cell and the fixed M2M devices is fixed. The dedicated cell is a cell whose communication frequency with the fixed M2M device is higher than that of the other cells.

[0017] According to the aforementioned structure, when multiple base stations are distributed within the tracking area, based on machine learning results, the fixed M2M device is configured to communicate only with specific dedicated cells among the multiple cells of the base stations. Therefore, even if communication conditions change, the fixed M2M device only communicates wirelessly with the dedicated cells of the specific base stations, thus avoiding the fixed M2M device randomly performing cell search and cell selection processing among the multiple cells capable of wireless communication.

[0018] As a result, fixed M2M devices can effectively suppress current consumption, thus mitigating battery life reduction and improving synchronization with base stations, while also suppressing communication speed degradation. Furthermore, because battery life is reduced, the battery life of fixed M2M devices can easily meet design specifications, and battery replacement may be virtually unnecessary, thereby ensuring product warranty for the fixed M2M device.

[0019] The above-mentioned objects, other objects, features, and advantages of the present invention will become clear from the following detailed description of preferred embodiments, with reference to the accompanying drawings.

[0020] The effects of the invention

[0021] In this invention, the above structure achieves the following effect in providing a wireless communication system: even when the M2M device, which is fixed in a specified location and powered by a battery, is specifically located in a tracking area where base stations are dispersed, the shortening of the battery life of the M2M device can be effectively suppressed. Attached Figure Description

[0022] [ Figure 1 ] Figure 1This is a schematic diagram illustrating an example of the structure of a wireless communication system according to a representative embodiment of the present disclosure.

[0023] [ Figure 2 ] Figure 2 A is a schematic diagram illustrating the frequent cell search and cell selection processes that occur in conventional wireless communication systems. Figure 2 B is shown in Figure 2 A schematic current waveform diagram showing the current consumption of a fixed M2M device over time under the condition shown in Figure A.

[0024] [ Figure 3 ] Figure 3 A is shown in Figure 1 The diagram illustrates the suppression of cell search and cell selection processes in a wireless communication system. Figure 3 B is shown in Figure 3 A schematic current waveform diagram showing the current consumption of a fixed M2M device (fixed terminal) over time under the condition shown in Figure A.

[0025] [ Figure 4 ] Figure 4 A is shown in Figure 1 The diagram shows a representative example of the functions of suppressing cell search and cell selection processing in a base station included in a wireless communication system. Figure 4 B is shown in Figure 1 The diagram shows a representative example of the functions of suppressing cell search and cell selection processing in a fixed M2M device (fixed terminal) included in the wireless communication system.

[0026] [ Figure 5 ] Figure 5 It is shown in Figure 4 A flowchart illustrates an example of the function to suppress cell search in a base station, as shown in Figure A.

[0027] [ Figure 6 ] Figure 6 It is shown in Figure 4 A flowchart illustrating an example of the function to suppress cell search in a fixed M2M device (fixed terminal) shown in Figure B. Detailed Implementation

[0028] [Insights that form the basis of this disclosure, etc.]

[0029] In wireless communication systems, the ability of a User Equipment (UE) to communicate with a large number of cells is generally preferred for maintaining a stable communication environment. However, according to our research, in the case of a battery-powered fixed M2M device, the ability to communicate with a large number of cells can excessively induce cell search and cell selection processing, thereby shortening battery life.

[0030] Therefore, through further in-depth research, the inventors independently discovered the following structure: a specific cell (dedicated cell) is deliberately set up among a large number of cells, and wireless communication is fixed between this dedicated cell and the fixed M2M device. According to this structure, not only can the shortening of the battery life of the fixed M2M device be effectively suppressed, but the synchronization connection between the fixed M2M device and the base station is also improved, and the reduction in communication speed is also suppressed. Furthermore, according to this structure, it is easy to ensure that the battery life of the fixed M2M device meets the design value, and in addition, battery replacement is substantially unnecessary, thus achieving product assurance for the fixed M2M device. In this way, the inventors have completed the technology disclosed herein.

[0031] Hereinafter, representative embodiments of the present invention will be described with reference to the accompanying drawings. Furthermore, in all the drawings, the same or equivalent elements are labeled with the same reference numerals, and repeated descriptions are omitted.

[0032] [Example of a wireless communication system structure]

[0033] First, refer to Figure 1 To illustrate specifically, a representative example of the wireless communication system involved in this disclosure (the wireless communication system involved in this embodiment) will be given. For example, in Figure 1 As schematically shown, the wireless communication system 10 according to this embodiment has multiple base stations 20 and multiple fixed terminals 30 as M2M (Machine to Machine) devices. Multiple tracking zones 11 are set in this wireless communication system 10. However, in Figure 1 In the diagram, for ease of explanation, a tracking area 11 is schematically shown only by a dashed ellipse.

[0034] exist Figure 1 In the illustrative example shown, three base stations 20 are configured within a tracking area 11, and each base station 20 is assigned a cell 12. Furthermore, in Figure 1In this document, for ease of explanation of the main parts of this disclosure, the three base stations 20 are designated as "Base Station 20A", "Base Station 20B", and "Base Station 20C", respectively, and the respective cells 12 defined for each base station 20A~20C are designated as "Cell 12A", "Cell 12B", and "Cell 12C". For example, taking base station 20A as an example, cell 12A is actually a circle centered on base station 20A, but... Figure 1 In the diagram, to facilitate representing a tracking area 11 as a circle, each cell 12A~12C is represented as a sector, with the boundary lines between each cell 12A~12C shown in [the diagram]. Figure 1 The diagram is schematically represented by thin lines.

[0035] At least one cell 12A can be configured for a base station 20A, but as will be described later, multiple cells 12A can also be configured for a base station 20A. In particular, this disclosure can be appropriately applied even in the case of configuring multiple cells 12A for a base station 20A. There are no particular limitations on the method of configuring multiple cells 12A for a base station 20A, and known methods can be used.

[0036] Taking 3GPP's (Third Generation Partnership Project) LTE (Long Term Evolution, base station OFDM modulation) as a representative example, the number of cells can be determined based on the bandwidth occupied by the base station. Specifically, for example, a base station supports various frequency bands such as band 8 (900MHz band) and band 1 (2GHz band). Bandwidths of 1.4MHz, 3MHz, 5MHz, 10MHz, 15MHz, and 20MHz are assigned to each base station. Within the bandwidth available for processing each base station's frequency band, the number of cells can be determined based on the desired number of resource blocks (RBs) that can be processed. Furthermore, the number of subcarriers (ch: number of users or data volume) can be increased within a resource block. Generally, band 8 radio waves have a longer propagation distance (larger cell area) and process less data (lower frequency, smaller bandwidth), while band 1 radio waves have a shorter propagation distance (smaller cell area) and process more data (higher frequency, larger bandwidth).

[0037] In addition, Figure 1 In addition to the three base stations 20 (base stations 20A-20C) used to illustrate the main parts of this disclosure, a base station 20 is also schematically illustrated outside a tracking area 11. This means that the wireless communication system 10 involved in this disclosure includes base station 20 in addition to base stations 20A-20C. Of course, more than one cell 12 is also configured in this schematically illustrated base station 20, and the base station 20 is also configured within other tracking areas 11. Figure 1 The illustrations of other tracking areas 11 are omitted. It goes without saying that a real wireless communication system 10 has a large number of base stations 20, a large number of cells 12, and a large number of tracking areas 11.

[0038] In the wireless communication system 10 disclosed herein, multiple base stations 20 (base stations 20A to 20C) are distributed in a decentralized manner. Specifically, the multiple base stations 20 are distributed in a decentralized manner, such as... Figure 1 As shown, a tracking area 11 only needs to include an area where the fixed terminal 30 can wirelessly communicate with multiple cells 12A-12C. In the wireless communication system 10 disclosed herein, it is not necessary for the base stations 20A-20C to be distributed across all tracking areas of the multiple tracking areas 11. For example, it can include areas where multiple base stations 20 are densely distributed, or areas where they are distributed at a standard density that is neither dense nor dispersed.

[0039] Furthermore, this disclosure does not specifically limit the conditions for the distributed configuration of multiple base stations 20. A representative example is the configuration of base stations 20 based on the cell ID (cell information of base station 20) identified by the UE and the receiving sensitivity. The receiving sensitivity can be determined based on the number of times the UE accesses the network. If the number of UE accesses the network is high, the receiving sensitivity of that cell is good, making it the optimal choice. Additionally, the decision regarding base station 20 can be based on the number of times the base station 20 accesses the network and the terminal information of the UE (fixed terminal 30), such as the ICCID (Integrated Circuit Card ID) and MYSDN (telephone number), as well as good receiving sensitivity. Furthermore, as representative receiving sensitivity indicators, reference indicators include (1) above -115dBm (outside the service area), (2) below -115dBm to -110dBm (weak electric field), (3) below -110dBm to -90dBm (normal), and (4) below -90dBm (strong electric field). Basically, (4) or (3) is selected.

[0040] The fixed terminal 30 is a battery-powered M2M device that is permanently installed in any location. Its specific structure is not particularly limited, as long as it can transmit and receive data with other M2M devices via wireless communication. Specific examples of the fixed terminal 30 are not particularly limited, but in this disclosure, a gas meter or water meter can be cited as an example. Generally, gas meters or water meters are battery-powered and permanently installed in any location. Therefore, if the fixed terminal 30 is a gas meter or water meter, the wireless communication system 10 disclosed herein can be appropriately applied.

[0041] Furthermore, in the wireless communication system 10 disclosed herein, the M2M device capable of communicating with the base station 20 (the cell 12 configured for the base station 20) is not limited to the fixed terminal 30. Generally, "terminal (device)" mostly refers to a device directly used by a user in a device connected to a communication network. Gas meters or water meters are generally installed in buildings or facilities that are users of gas or tap water; therefore, in this disclosure, such meters are referred to as fixed terminals 30. However, the wireless communication system 10 disclosed herein may also be a fixed M2M device that is not a "terminal (device)," such as an instrument or measuring device installed in a factory, etc.

[0042] Furthermore, the wireless communication system 10 disclosed herein may also include "terminals (devices)" other than fixed terminals 30 or fixed M2M devices. For example, a portable terminal (mobile M2M device) capable of movement, such as a mobile phone, smartphone, or tablet computer, may be able to communicate with the base station 20 (cell 12). Such a portable terminal does not conform to the M2M device, but the wireless communication system 10 disclosed herein may also have a structure that includes wireless communication devices other than M2M devices. In addition, such a portable terminal may also be configured to communicate with fixed terminals 30 or fixed M2M devices.

[0043] Furthermore, the wireless communication system 10 disclosed herein may include not only fixed M2M devices or portable terminals, but also mobile M2M devices. Examples of such mobile M2M devices include M2M devices mounted on automobiles or light vehicles, but there is no particular limitation. Additionally, in this embodiment, for ease of explanation, the wireless communication between the fixed terminal 30 and the base station 20 via the cell 12 is sometimes abbreviated as "communication between the fixed terminal 30 and the cell 12."

[0044] [Example of communication between fixed M2M devices and a cell]

[0045] Next, refer to Figure 2 A, Figure 2 B and Figure 3 A, Figure 3 B will specifically illustrate an example of wireless communication between cell 12 configured for base station 20 and fixed terminal 30, which is a fixed M2M device, in the wireless communication system 10 involved in this disclosure.

[0046] exist Figure 2 A and Figure 3 In diagram A, a scenario is illustrated where multiple cells 12 are configured for a single base station 20. For example, in... Figure 2In diagram A, three cells, 12A-1 to 12A-3, are designated for base station 20A. Each cell, 12A-1 to 12A-3, is symbolically arranged in a row as a circle. These cells 12A-1 to 12A-3 are designated for a single base station 20A by connecting the row of circular symbols with the symbol representing base station 20A using thin lines. The same applies to base station 20B and its designated cells 12B-1 to 12B-3, and to base station 20C and its designated cells 12C-1 to 12C-3.

[0047] In addition, Figure 2 A and Figure 3 In A, the symbols representing base stations 20A~20C, the symbols representing cells 12A-1~12A-3, 12B-1~12B-3, 12C-1~12C-3, and the block arrows CmA, CmB, and CmC that schematically represent wireless communication described later all contain hollow and grid-filled shapes, which schematically represent the differences in the frequency of wireless communication.

[0048] For example, cells 12A-1 to 12A-3 set for base station 20A are all shown with hollow diagrams, indicating that they are at the same frequency. Similarly, cells 12B-1 to 12B-3 set for base station 20B are shown with filled diagrams, indicating that they are at the same frequency. In addition, cells 12A-1 to 12A-3 and cells 12B-1 to 12B-3, which have different frequencies, are also illustrated by the difference between hollow and filled diagrams.

[0049] On the other hand, among the cells 12C-1 to 12C-3 configured for base station 20C, only cell 12C-2 is shown with a filled mesh pattern, while cells 12C-1 and 12C-3 are shown with a hollow pattern. This indicates that cells 12C-1 to 12C-3 of different frequencies can be mixed and configured within a single base station 20C. Furthermore, it goes without saying that for each actual base station 20A to 20C, more than three cells 12A to 12C can be configured, and more than three frequencies can be configured.

[0050] Figure 2 The illustrative communication example shown in A corresponds to... Figure 1 The diagram schematically illustrates the communication status between base stations 20A-20C and fixed terminal 30 within tracking area 11. If fixed terminal 30 is, for example, a gas meter or water meter as described above, it is generally driven intermittently. Figure 2 B is with Figure 2 A is a schematic current waveform diagram corresponding to the current consumption of the fixed terminal 30 over time.

[0051] Should Figure 2B shows the signal (paging signal) when any of the base stations 20A to 20C obtains synchronization (paging) from the repeating area setting terminal 30A (as a UE) via downlink communication (DL) at any period. This method is the power-saving technology eDRX (extended discontinuous reception), which confirms that the repeating area setting terminal 30A is not outside the service area. Figure 2 In diagram B, the arrows on the horizontal axis represent time passing from the left to the right of the graph, and the vertical axis, orthogonal to the horizontal axis, represents the magnitude of the current consumed.

[0052] In typical mobile communication, the UE is in sleep mode when not paging. Communication is usually switched to another base station's cell based on the paging signal reception sensitivity. For example, if the UE's reception sensitivity is not good, a cell search and cell selection process (reselection) is performed, allowing handover to a cell of another base station with a different TAC (Tracking Area Code).

[0053] In this disclosure, the UE is a fixed terminal 30. An example of a fixed terminal 30, as described above, could be a gas meter or a water meter. For example, if it is a gas meter, communication occurs between the flow measurement unit that measures the gas flow and the wireless communication unit that performs wireless communication, regardless of paging or sleep mode. If this communication is referred to as "internal communication" for ease of explanation, after the intra-terminal communication ends, the fixed terminal 30 pages and synchronizes with base stations 20A-20C, and then enters sleep mode. Therefore, such synchronization is performed periodically in the fixed terminal 30. Thus, as... Figure 2 As shown on the left side of A, if the fixed terminal 30 performs a normal synchronization operation, it generates a long, pulse-like synchronization operation current i1 at equal intervals, corresponding to the short-time drive.

[0054] Here, as Figure 2 As shown in Figure A, the fixed terminal 30 is configured to wirelessly communicate with any one of the cells 12A-1 to 12C-3 designated for base stations 20A to 20C. However, when communication conditions change within the tracking area 11, the fixed terminal 30 performs a detection of the communicable cell 12 (in... Figure 2 In the example shown in A, cell search is performed for cells 12A-1 to 12C-3, followed by cell selection processing (cell selection or cell reselection).

[0055] For example, such as Figure 2As indicated by block arrow CmA in section A, let's assume that fixed terminal 30 initially established wireless communication with cell 12A-1 of base station 20A. Subsequently, when communication conditions change and the reception sensitivity between fixed terminal 30 and cell 12A-1 becomes poor, fixed terminal 30 begins a cell search to detect cells 12A-1 that operate on the same frequency and different frequencies. Let's say that cell 12B-2 of base station 20B is detected through this cell search. Cell 12B-2 operates on a different frequency than cell 12A-1. Therefore, fixed terminal 30 performs cell selection processing (cell reselection) to begin wireless communication with cell 12B-2. When cell 12B-2 is reselected, fixed terminal 30 begins wireless communication with cell 12B-2 as indicated by block arrow CmB.

[0056] The current consumption at this time is as follows: Figure 2 As shown in Figure B, the current consumption corresponding to cell search of fixed terminal 30 is the vertically shaded cell search current i2, and the current consumption corresponding to cell selection processing is the horizontally shaded cell selection current i3. It can be seen that the pulse shape of both cell search current i2 and cell selection current i3 is larger than the pulse shape of synchronization operation current i1, meaning that the current consumption is greater.

[0057] exist Figure 2 In the example schematically shown in B, the current consumption during cell search is not only greater per unit time than during synchronization, but the duration of cell search is also longer. Furthermore, while the current consumption during cell selection is less per unit time than during synchronization, the duration of cell selection is significantly longer than the duration of cell search. In other words, the current consumption required for both cell search and cell selection is significantly increased compared to the flow measurement as a synchronization operation.

[0058] If such cell search and cell selection processes occur infrequently, they will not significantly deplete the battery capacity of the fixed terminal 30. However, if... Figure 2 As shown in Figure A, if the fixed terminal 30 can wirelessly communicate with any of the cells 12A-1 to 12C-3, cell search and cell selection processes will occur frequently. For example, if the fixed terminal 30 is wirelessly communicating with cell 12B-2, and the communication conditions change again, causing the wireless communication with cell 12B-2 to become poor, cell search and cell selection processes will be performed.

[0059] Subsequently, for example, even if cell 12C-3 of base station 20C is reselected for wireless communication as shown by the block arrow CmC, cell search and cell selection processing are still performed whenever communication conditions change. As a result, the battery charge of the fixed terminal 30 is significantly depleted, and battery life is shortened. For example, if the fixed terminal 30 is a gas meter, and it is a structure where the flow measurement unit and the wireless communication unit are integrated and share a battery (integrated type), then according to the metering law, the gas meter needs to be replaced every ten years. Therefore, the battery life of the gas meter is required to be at least ten years. However, if cell search and cell selection processing occur frequently, the battery life is significantly shortened, and it may be difficult to maintain ten years.

[0060] For gas meters, generally speaking, once the battery reaches the end of its lifespan, the gas meter itself is replaced, not the battery. Therefore, a shortened battery life leads to a shortened lifespan for the gas meter itself. This shortened battery life also means that the battery life deviated from the design specifications during the gas meter's design phase. Consequently, a shortened battery life also significantly impacts the product warranty of the gas meter.

[0061] Even if the fixed terminal 30 is a gas meter, and it has a separate flow measurement unit and a separate wireless communication unit with the wireless communication unit powered by a dedicated battery (separate type), the battery life of the wireless communication unit is required to be at least ten years, just like in an integrated gas meter. Therefore, even in the separate type of fixed terminal 30, just like in an integrated gas meter, a shortened battery life of the wireless communication unit will lead to a shortened lifespan of the gas meter itself, significantly impacting the product warranty of the gas meter.

[0062] In this regard, in the wireless communication system 10 disclosed herein, a specific cell 12 among cells 12A-1 to 12C-3 capable of communicating with the fixed terminal 30 is designated as a "dedicated cell," and the fixed terminal 30 is fixed to communicate wirelessly only with that dedicated cell. Essentially, in the wireless communication system 10, the UE is generally a portable terminal capable of movement; therefore, in this case, it is advantageous to be able to communicate well with various cells 12. However, as disclosed herein, in cases where the base stations 20 are distributed and the battery-powered fixed terminal 30 can communicate with many cells 12, it is advantageous to fix it to communicate wirelessly only with a specific cell 12, as has become clear through the inventors' in-depth research.

[0063] like Figure 3As shown by the block arrow CmA in A, for example, the fixed terminal 30 is fixed to communicate only with cell 12A-1 of base station 20A, which is one of cells 12A-1 to 12C-3. That is, in this example, cell 12A-1 is determined to be a dedicated cell, and the wireless communication between this dedicated cell and the fixed terminal 30 is fixed. Thus, even if the communication conditions change, the fixed terminal 30 will only communicate with the specific base station 20 (in Figure 3 A is a dedicated cell for base station 20A (in which...). Figure 3 In cell A, wireless communication is performed on cell 12A-1. Therefore, the fixed terminal 30 is prevented from randomly performing cell search and cell selection processing on multiple cells 12A-1 to 12C-3 that are capable of wireless communication.

[0064] If neither cell search nor cell selection processing occurs, then in fixed terminal 30, such as Figure 3 As shown in Figure B, the current i1 is consumed only by intermittently generating short, pulse-like synchronous actions at equal intervals. As a result, the fixed terminal 30 can effectively suppress its current consumption, thus effectively preventing the shortening of battery life. Furthermore, the synchronous connection with the specific base station 20 is also improved, and the reduction in communication speed is also suppressed. In addition, since the shortening of battery life is suppressed, the battery life of the fixed terminal 30 can easily meet the design value, and battery replacement can be virtually eliminated, thereby ensuring the product warranty of the fixed terminal 30.

[0065] In particular, if multiple cells 12 are configured for a base station 20 as illustrated in this embodiment, the number of cells 12 that the fixed terminal 30 can wirelessly communicate with increases relatively. However, if the fixed terminal 30 is configured to communicate only with a specific dedicated cell (e.g., cell 12A-1) among the multiple cells 12A-1 to 12C-3, even with the relatively increased number of cells 12, the fixed terminal 30 can be effectively prevented from randomly performing cell search and cell selection processes.

[0066] [The decision to establish a dedicated cell and examples of its fixed location]

[0067] Next, refer to Figure 4 A, Figure 4 B. Figure 5 as well as Figure 6 To specifically illustrate an example of the determination and fixation of a dedicated cell for wireless communication with a fixed terminal 30, which is a fixed M2M device, in the wireless communication system 10 involved in this disclosure.

[0068] In the wireless communication system 10 disclosed herein, a dedicated cell may be randomly selected from cells 12A-1 to 12C-3 that are capable of wireless communication with the fixed terminal 30. However, in this disclosure, the following structure can be described: machine learning is performed on the communication frequencies between the fixed terminal 30 and cells 12A-1 to 12C-3, and based on the learning results, cells with higher transmit and receive characteristics with the fixed terminal 30 than other cells 12 are determined as dedicated cells.

[0069] In this disclosure, the process of determining and fixing a dedicated cell can be performed by a fixed terminal 30 (fixed M2M device) or by a base station 20. Figure 4 A is a block diagram illustrating an example of the functional structure of base station 20 in this embodiment. Figure 4 B is a block diagram illustrating an example of the functional structure of the fixed terminal 30 in this embodiment.

[0070] like Figure 4 As shown in Figure A, the base station 20 according to this embodiment includes an antenna 21, a communication unit 22, a cell selection unit 23, a communication quality determination unit 24, and a cell setting unit 25. Additionally, the fixed terminal 30 according to this embodiment includes an antenna 31, a communication unit 32, a cell selection unit 33, and a communication quality determination unit 34.

[0071] exist Figure 4 In the example of base station 20 shown in Figure A, only one antenna 21 is schematically illustrated, but this disclosure is not limited to this, and base station 20 may also have multiple antennas 21. Similarly, in Figure 4 In the example of fixed terminal 30 shown in B, only one antenna 31 is schematically illustrated, but this disclosure is not limited to this, and fixed terminal 30 may also have multiple antennas 31. There are no particular limitations on the specific structure of antenna 21 or antenna 31, and structures known in the field of wireless communication can be appropriately used.

[0072] There are no particular limitations on the specific structures of the communication unit 22 of the base station 20 and the communication unit 32 of the fixed terminal 30; structures known in the field of wireless communication can be appropriately used. Typically, the communication unit 22 of the base station 20 can be configured to perform OFDMA (Orthogonal Frequency Division Multiple Access) transmission and reception, and the communication unit 32 of the fixed terminal 30 can be configured to perform SC-FDMA (Single-carrier Frequency Division Multiple Access) transmission and reception.

[0073] The cell selection unit 23 of base station 20 selects a dedicated cell as the optimal cell 12 based on the communication frequency between fixed terminal 30 and cell 12 using machine learning. The specific structure of the machine learning is not particularly limited; deep learning is a representative example. The communication quality assessment unit 24 periodically checks the communication quality between the selected dedicated cell and fixed terminal 30 and determines whether the communication quality is good or bad. The cell setting unit 25 sets and registers the dedicated cell selected by cell selection unit 23 to enable communication fixation for that dedicated cell.

[0074] The cell selection unit 23, communication quality determination unit 24, and cell setting unit 25 can all be functional structures composed of the computing and storage devices provided by the base station 20. The computing and storage devices provided by the base station 20 can be representatively integrated into a base station server structure. More specifically, the cell selection unit 23, communication quality determination unit 24, and cell setting unit 25 can have the following structures: the computing device provided by the base station server is formed by two or more of the following: a general-purpose processor, a dedicated processor, an integrated circuit, a FPGA (Field Programmable Gate Array), an ASIC (Application Specific Integrated Circuit), or a GPU, and operates according to a program stored in the storage device to realize the functions of the control unit 20.

[0075] Processors, as such computing devices, comprise circuits consisting of numerous transistors, memory, etc., and are therefore hardware circuits (or processing circuits). Integrated circuits or ASICs also include processors or processing blocks such as CPUs, and are similarly hardware circuits. FPGAs comprise a large number of integrated logic circuits (functional blocks), and are therefore hardware circuits. GPUs comprise a large number of parallel-mounted computing circuits (cores), and are therefore hardware circuits. Software, such as programs stored in storage devices, is used in the construction of hardware circuits (processors, integrated circuits, FPGAs, ASICs, GPUs, etc.). Alternatively, computing devices can also be constructed as logic circuits based on known switching elements, subtractors, comparators, etc.

[0076] Similar to the cell selection unit 23 of the base station 20, the cell selection unit 33 of the fixed terminal 30 selects a dedicated cell as the optimal cell 12 based on the communication frequency between the fixed terminal 30 and the cell 12 using machine learning. Similarly, the communication quality determination unit 34 of the fixed terminal 30 periodically checks the communication quality between the selected dedicated cell and the fixed terminal 30, and determines whether the communication quality is good or bad. The cell selection unit 33 and communication quality determination unit 34 of the fixed terminal 30 are also similar to those of the cell selection unit 23 and communication quality determination unit 24 of the base station 20, and can be functionally composed of the computing and storage devices provided by the fixed terminal 30. Their specific structures are the same as those of the base station 20, therefore detailed descriptions are omitted.

[0077] In the wireless communication system 10 disclosed herein, the structure of a dedicated cell can be determined by either the base station 20 or the fixed terminal 30. Therefore, if... Figure 4 As shown in Figure A, base station 20 includes a cell selection unit 23, a communication quality determination unit 24, and a cell setting unit 25. Fixed terminal 30 only needs to have these features. Figure 4 The structure of the cell selection unit 33 and the communication quality determination unit 34 shown in B is sufficient.

[0078] However, the setup and registration of dedicated cells is performed by base station 20. Therefore, for example, if fixed terminal 30 such as... Figure 4 Figure B shows a structure with a cell selection unit 33 and a communication quality determination unit 34. Therefore, base station 20 may not have these features. Figure 4 The cell selection unit 23 and communication quality determination unit 24 shown in Figure A are configured with a cell setting unit 25. Alternatively, both the base station 20 and the fixed terminal 30 may have a structure that allows for the determination of a dedicated cell. Figure 4 A, Figure 4 (Structure shown in B). In this case, during operation, the dedicated cell can be determined by either the base station 20 or the fixed terminal 30.

[0079] Reference Figure 4 A and Figure 5 This is a representative example illustrating the scenario where base station 20 determines a dedicated cell. First, as... Figure 5As shown, the fixed terminal 30 is fixedly installed at an appropriate position in the tracking area 11 and put into use (step S01). Regarding the installation and use of the fixed terminal 30, for example, the construction of the fixed terminal 30 is started, the receiving sensitivity of the candidate locations is measured, a location with appropriate receiving sensitivity at that time point is selected and the fixed terminal 30 is installed at that location, and a wireless communication connection test is performed between the installed fixed terminal 30 and any cell 12. If the connection test result is good, the construction is completed and the use of the fixed terminal 30 begins.

[0080] When the fixed terminal 30 begins operation, it randomly initiates wireless communication with the cell 12 that it can communicate with at an initial time. At this time, the cell selection unit 23 of the base station 20 acquires and records the communication data between itself and the fixed terminal 30 via the antenna 21 and the communication unit 22 (step S02). Examples of the communication data include the cell ID of the cell 12 with which the fixed terminal 30 communicated and the terminal ID of the fixed terminal 30. If... Figure 3 In the example shown, base station 20A acquires and records the terminal ID of fixed terminal 30 and the cell IDs of cells 12A-1 to 12C-3 in which fixed terminal 30 communicated.

[0081] Then, based on the recorded communication data, the cell selection unit 23 of base station 20 selects the cell ID of the dedicated cell as the best cell 12 through machine learning according to the communication frequency with multiple cells 12 (step S03). If it is Figure 3 In the example shown, base station 20A selects cell ID of cell 12A-1 as the optimal cell 12 based on the communication frequency between cells 12A-1 to 12C-3 and fixed terminal 30.

[0082] If a dedicated cell ID is selected, the cell ID is output from the cell selection unit 23 of the base station 20 to the cell setting unit 25. The cell setting unit 25 then fixes and registers the communication between the dedicated cell ID and the terminal ID of the fixed terminal 30 (step S04). Figure 3 In the example shown, base station 20A fixes and registers the cell ID of cell 12A-1 and the terminal ID of fixed terminal 30.

[0083] Subsequently, the communication quality determination unit 24 of base station 20 periodically confirms the communication quality between the dedicated cell and the fixed terminal 30 (step S05). If the communication quality is determined to be "good", the periodic communication quality confirmation is repeated (return to step S05). If the communication quality is determined to be "bad", the acquisition and recording of communication data between the cell selection unit 23 and the fixed terminal 30 is initiated to determine a new dedicated cell (return to step S02).

[0084] In this way, by periodically assessing the communication quality between the dedicated cell and the fixed terminal 30 in the base station 20, the fixed terminal 30 can periodically detect whether a decline in communication quality has occurred due to changes in communication conditions. Therefore, the base station 20 can effectively suppress the possibility of too little or too much processing for re-determining the dedicated cell.

[0085] There is no particular limitation on the specific method for confirming the communication quality between the fixed terminal 30 and the dedicated cell. Various known methods can be applied. A representative example is the method of comparing the transmission and reception characteristics between the fixed terminal 30 and the dedicated cell with a reference value. In the communication quality determination unit 24, the transmission and reception characteristics are compared with the reference value. If the transmission and reception characteristics are above the reference value, it is sufficient to determine that the communication quality is maintained ("good quality" in step S05). If the transmission and reception characteristics are below the reference value, it is sufficient to determine that the communication quality has deteriorated ("poor quality" in step S05), as described above. If it is determined that the communication quality has deteriorated, the dedicated cell can be re-determined by performing machine learning on the communication frequencies between multiple cells 12 and the fixed terminal 30, as described above (steps S02 to S04).

[0086] In this way, when communication conditions such as receiver sensitivity or traffic volume change due to the surrounding environment, causing a decline in the communication quality of the previously used dedicated cell, the base station 20 re-determines a new dedicated cell from multiple cells 12 based on the results of machine learning. This effectively avoids the risk of communication quality deterioration due to changes in communication conditions, and also avoids randomly performing cell search and cell selection processes to re-determine a new dedicated cell, thus effectively suppressing the shortening of battery life.

[0087] There are no particular limitations on the transmission and reception characteristics used to confirm communication quality; various well-known communication indicators can be used, but the electric field strength measured at the installation location of the fixed terminal 30 is a representative example. Other transmission and reception characteristics include data transmission speed (especially downlink transmission speed) and receiver sensitivity. As transmission and reception characteristics, only electric field strength can be used, or electric field strength can be used in combination with one or more other communication indicators. Therefore, the transmission and reception characteristics need to include at least the electric field strength measured at the installation location of the fixed terminal 30.

[0088] Next, refer to Figure 4 B and Figure 6 A representative example of a case where a fixed terminal 30 determines a dedicated cell will be explained. First, as... Figure 6 As shown, the fixed terminal 30 is fixedly positioned in an appropriate location within the tracking area 11 and used (step S11). This step S11 is the same as step S01 in the aforementioned determination of a dedicated cell by the base station 20 (see [reference]). Figure 5 ).

[0089] When the fixed terminal 30 begins operation, it randomly initiates wireless communication with the cell 12 that it can communicate with at an initial time. At this time, the cell selection unit 33 of the fixed terminal 30 acquires and records communication data with the base station 20 via the antenna 31 and the communication unit 32 (step S12). Examples of this communication data include the cell ID of the cell 12 with which the fixed terminal 30 communicated and the ID (base station ID) of the base station 20 that configured the cell 12. If... Figure 3 In the example shown, the fixed terminal 30 acquires and records the base station IDs of base stations 20A to 20C and the cell IDs of cells 12A-1 to 12C-3 set for these base stations 20A to 20C.

[0090] Then, the cell selection unit 33 of the fixed terminal 30, based on the recorded communication data and according to the communication frequency with multiple cells 12, selects the cell ID of the dedicated cell as the best cell 12 through machine learning (step S13). If it is Figure 3 In the example shown, the fixed terminal 30 selects the cell ID of cell 12A-1 of base station 20A as the optimal cell 12 based on the communication frequency between cells 12A-1 to 12C-3.

[0091] If a dedicated cell ID is selected, the cell selection unit 33 of the fixed terminal 30 sends an instruction to the base station 20A to fix and register the communication with the dedicated cell ID (step S14). In the base station 20A, when it receives the instruction from the fixed terminal 30, it outputs the dedicated cell ID to the cell setting unit 25 and registers the configuration to fix the communication between the dedicated cell ID and the terminal ID of the fixed terminal 30. If... Figure 3 In the example shown, according to the instruction from the fixed terminal 30, the base station 20A fixes and registers the cell ID of cell 12A-1 with the terminal ID of the fixed terminal 30.

[0092] Subsequently, the communication quality determination unit 34 of the fixed terminal 30 periodically checks the communication quality between the dedicated cell and the fixed terminal 30 (step S15). If the communication quality is determined to be "good", the periodic communication quality check is repeated (return to step S15). If the communication quality is determined to be "bad", the acquisition and recording of communication data between the fixed terminal 30 and the cell selection unit 33 begins to determine a new dedicated cell (return to step S12).

[0093] In this way, the fixed terminal 30 periodically assesses the communication quality with the dedicated cell, thereby periodically detecting whether a decline in communication quality has occurred due to changes in communication conditions. Therefore, the fixed terminal 30 can effectively suppress the possibility of too little or too much processing for re-determining the dedicated cell. Furthermore, the specific method for confirming the communication quality in the fixed terminal 30 is the same as that in the base station 20 described above.

[0094] Furthermore, when the fixed terminal 30 determines the dedicated cell through machine learning, a simple structure is sufficient for the fixed terminal 30 to send an instruction to the base station 20, causing the base station 20 to fix and register the communication with the dedicated cell. Therefore, the communication fixation with the dedicated cell is set and registered by the base station 20, and the fixed terminal 30 does not need to have a structure for setting and registering the communication fixation. Consequently, no power consumption is generated in the fixed terminal 30 for setting and registering the communication fixation, thus effectively preventing further shortening of battery life.

[0095] (Postscript)

[0096] Based on the description of the above embodiments, the following technology is disclosed in this specification.

[0097] (Technology 1) A wireless communication system includes a plurality of base stations configured with at least one cell and a plurality of M2M (Machine to Machine) devices capable of wireless communication with the base stations, and a plurality of tracking zones are defined. Among the M2M devices are fixed M2M devices that are fixedly installed and battery-powered. The plurality of base stations are configured such that the tracking zones include areas fixedly installed at locations where the plurality of cells and the fixed M2M devices can wirelessly communicate. The fixed M2M devices or base stations include fixed M2M devices or base stations configured such that: a dedicated cell is determined by performing machine learning on the communication frequencies between the plurality of cells and the fixed M2M devices, and wireless communication between the dedicated cell and the fixed M2M devices is fixed. The dedicated cell is a cell whose communication frequency with the fixed M2M devices is higher than that of the other cells.

[0098] According to the aforementioned structure, when multiple base stations are distributed within the tracking area, based on machine learning results, the fixed M2M device is configured to communicate only with specific dedicated cells among the multiple cells of the base stations. Therefore, even if communication conditions change, the fixed M2M device only communicates wirelessly with the dedicated cells of the specific base stations, thus avoiding the fixed M2M device randomly performing cell search and cell selection processing among the multiple cells capable of wireless communication.

[0099] As a result, fixed M2M devices can effectively suppress current consumption, thus mitigating battery life reduction and improving synchronization with base stations, while also suppressing communication speed degradation. Furthermore, because battery life is reduced, the battery life of fixed M2M devices can easily meet design specifications, and battery replacement may be virtually unnecessary, thereby ensuring product warranty for the fixed M2M device.

[0100] (Technology 2) The wireless communication system according to Technology 1, wherein,

[0101] The fixed M2M device or the base station compares the transmit and receive characteristics between the dedicated cell and the fixed M2M device with a reference value. If the transmit and receive characteristics are lower than the reference value, the fixed M2M device or the base station determines that the communication quality has degraded. By performing machine learning on the communication frequencies between multiple cells and the fixed M2M device during the learning period, the dedicated cell is re-determined.

[0102] According to the aforementioned structure, when communication conditions such as the receiver sensitivity or traffic volume of a cell change due to the surrounding environment, causing a decline in the communication quality of a previously used dedicated cell, a new dedicated cell is re-determined from multiple cells based on machine learning results. This effectively avoids the risk of communication quality deterioration due to changes in communication conditions and also avoids the need for random cell search and cell selection processes to determine a new dedicated cell, thus effectively suppressing the shortening of battery life.

[0103] (Technology 3) The wireless communication system according to Technology 2, wherein,

[0104] The communication quality between the dedicated cell and the fixed M2M device is evaluated periodically.

[0105] According to the aforementioned structure, the communication quality of dedicated cells is evaluated periodically, thereby enabling regular monitoring of whether a decline in communication quality has occurred due to changes in communication conditions. Consequently, in fixed M2M equipment or base stations, the possibility of insufficient or excessive processing for re-determining dedicated cells can be effectively suppressed.

[0106] (Technology 4) The wireless communication system according to Technology 2 or Technology 3, wherein,

[0107] The transmission and reception characteristics include at least the electric field strength measured at the location where the fixed M2M device is installed.

[0108] According to the structure, at least the electric field strength is measured at the location where the fixed M2M device is installed, and the electric field strength is used as an evaluation of the transmission and reception characteristics between the fixed M2M device and the cell. As a result, the fixed M2M device or base station can more appropriately determine the dedicated cell with higher transmission and reception characteristics.

[0109] (Technology 5) A wireless communication system according to any one of technologies 1 to 4, wherein,

[0110] The base station is configured with multiple cells.

[0111] According to the aforementioned structure, multiple cells are configured for a single base station, thus relatively increasing the number of cells from which wireless communication can be performed for a fixed M2M device. In response, the fixed M2M device or base station, based on machine learning results, registers the fixed M2M device to communicate only with specific dedicated cells among these multiple cells. Therefore, even with the relatively increased number of cells, the fixed M2M device can effectively avoid randomly performing cell search and cell selection processes. Consequently, battery life shortening can be effectively suppressed, synchronization with the base station is improved, and communication speed reduction can also be prevented.

[0112] (Technology 6) A wireless communication system according to any one of technologies 1 to 5, wherein,

[0113] When the fixed M2M device determines the dedicated cell through machine learning, the fixed M2M device sends an instruction to the base station to fix and register the communication between the base station and the dedicated cell.

[0114] According to the aforementioned structure, communication with the dedicated cell is fixed and registered by the base station; therefore, fixed M2M devices do not require a structure for setting up and registering fixed communication. Consequently, no power consumption for setting up and registering fixed communication occurs in fixed M2M devices, thus effectively preventing further shortening of battery life.

[0115] (Technology 7) A wireless communication system according to any one of Technologies 1 to 6, wherein,

[0116] The tracking area includes a tracking zone in which the base stations are densely arranged.

[0117] (Technology 8) A wireless communication system according to any one of Technologies 1 to 7, wherein,

[0118] The fixed M2M device is a gas meter or a water meter.

[0119] According to the structure described, the fixed M2M device is a gas meter or a water meter, thus enabling the appropriate application of these battery-powered and fixedly installed meters to wireless communication systems.

[0120] Furthermore, the present invention is not limited to the embodiments described above, and various modifications can be made within the scope of the claims. Therefore, embodiments obtained by appropriately combining the technical means disclosed in different embodiments and multiple modifications are also included within the technical scope of the present invention.

[0121] Furthermore, based on the foregoing description, many improvements and other embodiments of the present invention will be apparent to those skilled in the art. Therefore, the foregoing description should be interpreted as illustrative only and is provided for the purpose of teaching those skilled in the art the best mode for carrying out the invention. Details may be made that allow for substantial changes to the construction and / or function of the invention without departing from its spirit.

[0122] Industrial availability

[0123] This invention can be widely and appropriately applied in the field of wireless communication, which includes multiple base stations and multiple M2M devices, particularly in the field of wireless communication, which includes fixed M2M devices that are fixedly installed in a specified location and are powered by batteries.

[0124] Explanation of reference numerals in the attached figures

[0125] 10: Wireless Communication System

[0126] 11: Tracking Area

[0127] 12A~12C: Residential Area

[0128] 12A-1~12A-3: Residential area

[0129] 12B-1~12B-3: Residential Area

[0130] 12C-1~12C-3: Community

[0131] 20: Base station

[0132] 20A~20C: Base Station

[0133] 21: Antenna

[0134] 22: Ministry of Communications

[0135] 23: Selected Community Section

[0136] 24: Communication Quality Assessment Department

[0137] 25: Community Setting Department

[0138] 30: Fixed terminal (fixed M2M device)

[0139] 31: Antenna

[0140] 32: Ministry of Communications

[0141] 33: Selected Community Section

[0142] 34: Communication Quality Assessment Department

[0143] i1: Synchronous operation consumes current

[0144] i2: Cell search consumes current

[0145] i3: Cell selection consumes current

Claims

1. A wireless communication system, characterized in that, It includes multiple base stations, each with at least one cell configured, and multiple M2M devices (machine-to-machine devices) capable of wireless communication with these base stations, and multiple tracking zones are defined. The M2M devices include stationary M2M devices that are permanently installed and powered by batteries. The multiple base stations are configured such that the tracking area includes areas fixedly located at positions where the multiple cells and the fixed M2M device can wirelessly communicate. The fixed M2M device or the base station includes a fixed M2M device or base station configured in such a way that a dedicated cell is determined by performing machine learning on the communication frequencies between the multiple cells and the fixed M2M device, and the wireless communication between the dedicated cell and the fixed M2M device is fixed. The dedicated cell is a cell whose communication frequency with the fixed M2M device is higher than that of the other cells.

2. The wireless communication system according to claim 1, wherein, The fixed M2M device or the base station compares the transmit and receive characteristics between the dedicated cell and the fixed M2M device with a reference value. If the transmit and receive characteristics are lower than the baseline value, the fixed M2M device or the base station determines that the communication quality has degraded. During the learning period, the dedicated cell is re-determined by performing machine learning on the communication frequencies between multiple cells and the fixed M2M device.

3. The wireless communication system according to claim 2, wherein, The communication quality between the dedicated cell and the fixed M2M device is evaluated periodically.

4. The wireless communication system according to claim 2, wherein, The transmission and reception characteristics include at least the electric field strength measured at the location where the fixed M2M device is installed.

5. The wireless communication system according to claim 1, wherein, The base station is configured with multiple cells.

6. The wireless communication system according to claim 1, wherein, In the case where the fixed M2M device determines the dedicated cell through machine learning. The fixed M2M device sends instructions to the base station to fix and register the communication between the base station and the dedicated cell.

7. The wireless communication system according to claim 1, wherein, The tracking area includes tracking zones where the base stations are distributed.

8. The wireless communication system according to any one of claims 1 to 7, wherein, The fixed M2M device is a gas meter or a water meter.

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