Base Station, Wireless Communication Method, and Wireless Communication System

Abstract

Provided are a base station, a wireless communication method, and a wireless communication system that can avoid interference effects on other wireless communication systems and provide high-speed communication services in a shared frequency band of wireless communication. A base station (30x) is provided. When other wireless communication systems do not use the shared segment, it uses a 3-MHz or 5-MHz carrier of this system with increased throughput and a wider frequency band than that of other wireless communication systems. When other wireless communication systems use the shared segment, it uses a 1.4-MHz carrier of this system with a narrower frequency band than that of other wireless communication systems.

Description

[0001] This application is a divisional application of the invention patent application with the application date of August 4, 2016, application number 201680047112.X, and invention name "Base Station and Wireless Communication Method". Technical Field

[0002] The present invention relates to a base station for performing wireless communication and a wireless communication method. Background Art

[0003] As the frequency band of PHS (Personal Handy-phone System), the frequency band from 1884.5 MHz to 1915.7 MHz is allocated, and among them, the frequency band from 1893.5 MHz to 1906.1 MHz is a common use frequency band for the public and individual businesses. Within this common use frequency band, public PHS, individual business PHS, DECT (Digital Enhanced Cordless Telecommunications), etc. can be utilized.

[0004] In the future, in this common use frequency band, it is expected to use a wireless communication method of XGP (Extended Global Platform) that can realize M2M (Machine-to-Machine), IoT (Internet of Things), etc., and high-quality communication services such as high speed and low latency are envisioned.

[0005] For example, in the wireless communication method of TD-LTE (Time Division duplex-Long Term Evolution) used in the XGP method, the carrier for transmission can use frequency bandwidths of 1.4 MHz, 3 MHz, 5 MHz, 10 MHz, and 20 MHz (hereinafter referred to as bandwidth). (Non-Patent Document 1, 2, etc.). The number of resource blocks (RB) included in each bandwidth is 6 RB, 15 RB, 25 RB, 50 RB, and 100 RB respectively, and the wider the bandwidth, the higher the communication speed.

[0006] Prior Art Documents

[0007] Non-Patent Documents

[0008] Non-Patent Document 1: 3GPP TS 36.101 Ver.9.0.0 "LTE; Evolved Universal Terrestrial Radio Access (U-UTRA); User Equipment (UE) radio transmission and reception"

[0009] Non - Patent Document 2: 3GPP TS 36.211 Ver.9.0.0 “LTE; Evolved Universal Terrestrial Radio Access (U - UTRA); Physical channels and modulation” Summary of the Invention

[0010] Problems to be Solved by the Invention

[0011] In the above - mentioned shared frequency band, if a base station in the TD - LTE mode uses a relatively wide bandwidth, it may cause interference to the systems used in other wireless communication modes.

[0012] Therefore, in view of the above - mentioned situation, the object of the present invention is to provide a base station and a wireless communication method that can avoid interference to wireless communication systems used in other wireless communication systems in the shared frequency band of wireless communication.

[0013] Means for Solving the Problems

[0014] The base station of the present invention is a base station of a wireless communication system that shares the same frequency band with other wireless communication systems, and has the following structure: when the other wireless communication systems do not use the frequency band, it uses a wide - frequency - band carrier of the present system with a higher throughput and a wider frequency than that of the other wireless communication systems; when the other wireless communication systems use the frequency band, it uses a narrow - frequency - band carrier of the present system with a narrower frequency than that of the other wireless communication systems.

[0015] In addition, the base station of the present invention has the following structure: when the other wireless communication systems do not use the frequency band, it switches between the wide - frequency - band carrier and the narrow - frequency - band carrier in time to use them alternately.

[0016] In addition, the base station of the present invention has the following structure: the other wireless communication systems include a first wireless communication system and a second wireless communication system with a narrower carrier frequency than that of the first wireless communication system. When the first wireless communication system does not use the frequency band and the second wireless communication system uses the frequency band, it uses a medium - frequency - band carrier of the present system that is narrower than the wide - frequency - band carrier and has a higher throughput than that of the other wireless communication systems.

[0017] In addition, the base station of the present invention has the following structure: when the first wireless communication system does not use the frequency band and the second wireless communication system uses the frequency band, it switches between the medium - frequency - band carrier and the narrow - frequency - band carrier in time to use them alternately.

[0018] In addition, the base station of the present invention has the following structure. When using the carrier with a wide frequency band, the carrier with the wide frequency band is used for a short time initially and then gradually used for a long time.

[0019] The wireless communication method of the present invention is a wireless communication method for a wireless communication system that shares the same frequency band with other wireless communication systems, and includes the following steps: when the other wireless communication system does not use the frequency band, using the carrier with a wide frequency band of the present system whose throughput is higher than that of the other wireless communication system; when the other wireless communication system uses the frequency band, using the carrier with a narrow frequency band of the present system that is narrower than that of the other wireless communication system.

[0020] Advantages of the Invention

[0021] The base station and the wireless communication method of the present invention can avoid the interference impact on other wireless communication systems in the shared frequency band of wireless communication. Description of the Drawings

[0022] Figure 1 It is a diagram showing the operation of wireless communication according to an embodiment of the present invention.

[0023] Figure 2 It is a diagram for explaining the shared section according to an embodiment of the present invention.

[0024] Figure 3 It is a diagram for explaining the carrier according to an embodiment of the present invention.

[0025] Figure 4 It is a block diagram of the base station that is the object according to an embodiment of the present invention.

[0026] Figure 5 It is a flowchart showing an operation example according to an embodiment of the present invention.

[0027] Reference Signs

[0028] 10p, 10x, 10d Wireless Terminals

[0029] 20p, 20x, 20d Control Devices

[0030] 30p, 30x, 30d Base Stations

[0031] 31, 32 Radio Sections

[0032] 33 Detection Section

[0033] 34 Signal Processing Section

[0034] 35 Control Section

[0035] 36 Circuit section. Detailed implementation mode

[0036] Hereinafter, the implementation mode of the present invention will be described with reference to the accompanying drawings.

[0037] Figure 1 It is a diagram showing the operation of wireless communication related to the implementation mode of the present invention. Figure 1 A wireless communication system corresponding to multiple wireless communication methods is used, and it has wireless terminals 10p, 10x, 10d corresponding to each wireless communication method, base stations 30p, 30x, 30d, and control devices 20p, 20x, 20d for controlling the base stations 30p, 30x, 30d.

[0038] For example, the wireless terminal 10p and the base station 30p correspond to the wireless communication method P, the wireless terminal 10x and the base station 30x correspond to the wireless communication method X, and the wireless terminal 10d and the base station 30d correspond to the wireless communication method D.

[0039] In the implementation mode of the present invention, on the premise that the base station 30x exists, at least one of the base station 30p or the base station 30d sometimes exists around the base station 30x and sometimes does not. For example, when the wireless network is operated in an individual business mode, at least one of the base station 30p or the base station 30d sometimes exists.

[0040] In addition, Figure 1 Three methods are shown for the wireless communication method, but it is not limited to three.

[0041] These wireless communication methods are used in the shared section that shares the same frequency band. Next, the shared section will be described.

[0042] Figure 2 It is a diagram for explaining the shared section related to the implementation mode of the present invention.

[0043] For example, as Figure 2 shown, the shared section is between the frequency bands used by the public, that is, the public sections. This shared section uses the wireless communication method P, the wireless communication method X, and the wireless communication method D (hereinafter, each method is only referred to as method P, method X, and method D). These wireless communication methods are easily all used in the shared section. In facilities such as hospitals and offices, specific areas, etc., sometimes one or more wireless communication methods are used, but sometimes none are used.

[0044] Next, the carrier with a wide frequency used in the shared section will be described.

[0045] Figure 3 It is a diagram for explaining the carrier related to the implementation mode of the present invention.

[0046] For the system of Mode D (the first wireless communication system), as Figure 3 shown, there are five carriers with a given frequency bandwidth in the common segment, and a maximum of five carriers are used.

[0047] For the system of Mode X, it is envisioned to use the TD-LTE mode. As Figure 3 shown, in the common segment, there are five carriers with a frequency bandwidth of 1.4 MHz, and a maximum of five carriers are used. In addition, as another mode, as Figure 3 shown, in the common segment, there are two carriers with a frequency bandwidth of 3 MHz, and a maximum of two carriers are used. In addition, as another mode, as Figure 3 shown, in the common segment, there is one carrier with a frequency bandwidth of 5 MHz.

[0048] For the system of Mode P (the second wireless communication system), as Figure 3 shown, in the common segment, there are 18 carriers with a given frequency bandwidth, and a maximum of 18 carriers are used.

[0049] In addition, the throughput of the 1.4-MHz-wide (narrow frequency bandwidth) carriers of Mode X is lower than that of the carriers of Mode D, and the throughput of the 3-MHz-wide (wide frequency bandwidth or medium frequency bandwidth) and 5-MHz-wide (wide frequency bandwidth) carriers of Mode X is higher than that of the carriers of Mode D. Among them, since the 3-MHz-wide and 5-MHz-wide carriers of Mode X are in the wide frequency band, they may cause interference to other wireless communication systems.

[0050] Next, the base station related to the embodiment of the present invention will be described.

[0051] Figure 4 is a block diagram of the base station related to Mode X.

[0052] The base station 30x includes: two radio units 31, 32; a detection unit 33 related to carrier sense; a signal processing unit 34 for processing radio signals; a control unit 35 for controlling various operations; and a circuit unit 36 for communicating with the network.

[0053] The radio unit 31 performs wireless communication in the TD-LTE mode. The receiving unit of the radio unit 31 outputs the radio signal received from the wireless terminal 10x to the signal processing unit 34. The transmitting unit of the radio unit 31 transmits the information output from the signal processing unit 34 to the wireless terminal 10x as a radio signal.

[0054] The radio unit 32 performs carrier sense, for example, during the communication of the radio unit 31. The receiving unit of the radio unit 32 outputs the received radio signal to the signal processing unit 34. The transmitting unit of the radio unit 32 transmits the information output from the signal processing unit 34 as a radio signal.

[0055] The detection unit 33 detects a carrier from the wireless signal and outputs the carrier sensing information during carrier sensing to the control unit 35.

[0056] The signal processing unit 34 processes the wireless signals from the receiving units of the wireless unit 31 and the wireless unit 32, and outputs the obtained information to the control unit 35. In addition, the signal processing unit 34 outputs the information output from the control unit 35 as a wireless signal to the transmitting units of the wireless unit 31 and the wireless unit 32.

[0057] The control unit 35 is composed of a CPU, a memory, etc., and controls various operations. The circuit unit 36 is a network interface for communicating with the control device 20x and the network.

[0058] Next, the operation of the control unit 35 of the base station 30x will be described.

[0059] As Figure 3 described, the base station 30x uses carriers with frequency bandwidths of 1.4 MHz, 3 MHz, and 5 MHz. However, if carriers of 3 MHz and 5 MHz are used, it is feared that other wireless communication systems may not be able to be used in the shared section. Therefore, the use of carriers of 3 MHz and 5 MHz is restricted.

[0060] For example, the base station 30x performs the following operations.

[0061] · When the communication starts, the base station 30x performs carrier sensing to detect whether there is any other wireless communication system in operation. In the case where another wireless communication system is detected, an operation that has little impact (can coexist) on the detected other wireless communication system is selected to start the operation.

[0062] · The base station 30x also performs carrier sensing during operation. In the case where another wireless communication system is further detected, the operation is switched to an operation that has little impact on that system to continue the operation.

[0063] · An operation that has little impact on other wireless communication systems refers to an operation that reduces the pre-interference to other wireless communication systems. For example, it refers to reducing the number of channels (waves) used in the current operation, narrowing the frequency bandwidth, reducing the transmission output, shortening the transmission time (reducing the duty cycle of transmission), etc.

[0064] · When the base station 30x does not detect other wireless communication systems for a certain period of time, conversely to the above operations, an operation that has a greater impact on other wireless communication systems is performed.

[0065] · The operations that bring the above impacts are determined considering the detected system, the level at which another wireless communication system is detected, the detection frequency, etc.

[0066] ·In operation, it also includes the case of switching between multiple operations. For example, after switching to a carrier with a wide frequency band, after operating for a certain period of time, a switch is made to operate with a carrier with a narrow frequency band for a certain period. Or it means that after operating an operation using a large number of channels for a certain period, an operation with a smaller number of channels is performed, etc.

[0067] ·When the base station 30x switches between multiple operations, the operation time of each operation reflects the result of carrier sensing. That is, for example, when the time during which no other wireless communication system is detected by carrier sensing is long, the operation time of an operation that has a greater impact on other wireless communication systems (for example, a wider frequency band, a larger number of channels, etc.) is lengthened. Conversely, when another wireless communication system is detected, the operation time of an operation that has a smaller impact on other wireless communication systems is lengthened, etc.

[0068] ·When the width of the shared frequency band changes, it includes the case where the operation selected by carrier sensing is also changed. For example, when the frequency band is widened, it includes the case of selecting an operation that is different from the operation before widening even if the detected system, detection level, and detection frequency are the same by carrier sensing (for example, having a greater impact on other wireless communication systems). In addition, when the shared frequency band is narrowed, it also includes the case of performing the opposite operation to the above.

[0069] ·The meaning of other wireless communication systems is systems that are not the system used by itself, and as wireless communication methods, it includes both the same method and different methods.

[0070] Next, an example of the operation of the control unit 35 of the base station 30x is described using a flowchart. Figure 5 It is a flowchart showing an example of the operation related to the embodiment of the present invention.

[0071] First, when starting wireless communication, the control unit 35 performs carrier sensing for a long time (for example, 24 hours, etc.) to confirm whether carriers of mode D and mode P are not detected (S11).

[0072] When these two carriers are not detected, the control unit 35 alternately uses a 5 MHz carrier and a 1.4 MHz carrier (S12). For example, in this case, as Figure 3 shown, after the control unit 35 operates a 5 MHz carrier for a certain period of time (for example, 3 hours, etc.), it switches to a 1.4 MHz carrier and operates for a certain period of time (for example, 1 hour, etc.). After operating the 5 MHz carrier for a certain period of time again, it switches to a 1.4 MHz carrier and operates for a certain period of time, and the above operations are repeated.

[0073] By using a 5 MHz carrier, it is possible to provide a communication service with good throughput without causing interference to other wireless communication systems.

[0074] During operation, the control unit 35 also performs carrier sensing (S13) to determine whether other wireless communication systems are not detected or are detected (S14). In the case where other wireless communication systems are not detected (Yes in S14), the control unit 35 then executes step S12.

[0075] In the case where other wireless communication systems are detected, the control unit 35 switches to an operation with less impact on that system and continues the operation. In Figure 5 In this case, when mode P is detected in step S14, step S22 is executed. When mode D is detected in step S14, step S31 is executed.

[0076] On the other hand, in step S11, when mode P or mode D is detected, the control unit 35 determines whether mode D is not detected or is detected (S21).

[0077] In the case where mode D is not detected, that is, in the case where mode P is detected, the control unit 35 alternately uses a 3 MHz carrier and a 1.4 MHz carrier (S22). For example, in this case, as Figure 3 shown, after the control unit 35 uses the 3 MHz carrier for a certain period of time (for example, 3 hours, etc.), it switches to the 1.4 MHz carrier and uses it for a certain period of time (for example, 1 hour, etc.), and after using the 3 MHz carrier for a certain period of time again, it switches to the 1.4 MHz carrier and uses it for a certain period of time, repeating the above actions.

[0078] By using a 3 MHz carrier, it is possible to provide a communication service with good throughput without causing interference to other wireless communication systems.

[0079] During operation, the control unit 35 also performs carrier sensing (S23) to determine whether other wireless communication systems are not detected or are detected (S24). In the case where other wireless communication systems are not detected (Yes in S24), the control unit 35 then executes step S11.

[0080] In the case where other wireless communication systems are detected, the control unit 35 switches to an operation with less impact on that system and continues the operation. In Figure 5 In this case, when mode P is subsequently detected in step S24, step S22 is executed. When mode D is detected in step S24, step S31 is executed.

[0081] On the other hand, when mode D is detected in step S21, the control unit 35 uses a 1.4 MHz carrier (S31).

[0082] In operation, the control unit 35 also performs carrier sensing (S32), and determines whether no other wireless communication system is detected or an other wireless communication system is detected (S33). When no other wireless communication system is detected (Yes in S33), the control unit 35 then executes step S11.

[0083] When an other wireless communication system is detected, the control unit 35 switches to an operation that has less impact on that system and continues the operation. In Figure 5 In this case, when only mode P is detected in step S33, step S21 is executed. When mode D is then detected in step S33, step S31 is executed.

[0084] As described above, when the shared segment is not used by other wireless communication systems, the base station 30x uses the 3-MHz or 5-MHz carrier of this system with increased throughput that has a wider frequency bandwidth than that of other wireless communication systems. When the shared segment is being used by other wireless communication systems, the base station 30x uses the 1.4-MHz carrier of this system that has a narrower frequency bandwidth than that of other wireless communication systems. Therefore, it is possible to avoid the interference impact on other wireless communication systems within the shared frequency band for wireless communication, and it is possible to provide high-speed communication services.

[0085] As another embodiment, in the above, after the control unit 35 uses the 3-MHz or 5-MHz carrier for a certain period of time, it switches to the 1.4-MHz carrier and operates for a certain period of time. However, in order not to cause an interference impact on other wireless communication systems, the operation time of the 3-MHz or 5-MHz carrier may initially be short, and when no other wireless communication system is detected through carrier sensing, the operation time is gradually increased.

[0086] In steps S12 and S22, the 1.4-MHz carrier is alternately used. However, in order not to cause an interference impact on other wireless communication systems, it is also possible that when the control unit 35 uses the 1.4-MHz carrier, it initially uses one wave of the 1.4-MHz carrier, then uses two waves of the 1.4-MHz carrier, then uses three waves of the 1.4-MHz carrier, then uses four waves of the 1.4-MHz carrier, and then uses five waves of the 1.4-MHz carrier, and thus gradually increases.

[0087] In step S12, the 5-MHz carrier is used. However, in order not to cause an interference impact on other wireless communication systems, it is also possible to initially use the 3-MHz carrier and then use the 5-MHz carrier.

[0088] In addition, the above description only shows specific preferred embodiments for the purpose of explaining and exemplifying the present invention. Therefore, the present invention is not limited to the above embodiments, and includes more changes and modifications within the scope not departing from the essence.

[0089] In addition, this application is based on the Japanese Patent Application (Japanese Patent Application No. 2015-158698) filed on August 11, 2015, and the whole of it is incorporated herein by reference. In addition, all references cited herein are incorporated as a whole.

Claims

1. A base station, which is a base station of a first wireless communication system, The base station has a control unit that shares the same frequency band with a second wireless communication system, The control unit uses TD-LTE as the communication method of the first wireless communication system, The communication method of the first wireless communication system is different from that of the second wireless communication system, At least 1.4 MHz and 5 MHz exist in the bandwidth of the first wireless communication system, At 1.4 MHz, multiple carriers can be used, and at 5 MHz, one carrier can be used, When the second wireless communication system does not use the frequency band, the control unit can perform wireless communication using a carrier with a bandwidth of 5 MHz of the first wireless communication system.

2. The base station according to claim 1, wherein, The throughput of the carrier with a bandwidth of 5 MHz of the first wireless communication system is higher than that of the carrier with the bandwidth of the second wireless communication system.

3. The base station according to claim 1, wherein, In the communication method of the second wireless communication system, at least one of PHS and DECT exists.

4. The base station according to claim 1 or 2, wherein, When using a bandwidth of 1.4 MHz of the first wireless communication system, the control unit selects a 1.4 MHz carrier so as not to cause interference to the second wireless communication system.

5. A wireless communication method, which is a wireless communication method of a first wireless communication system that shares the same frequency band with a second wireless communication system, As the communication method of the first wireless communication system, the base station uses TD-LTE, and the communication method of the first wireless communication system is different from that of the second wireless communication system, At least 1.4 MHz and 5 MHz exist in the bandwidth of the first wireless communication system, At 1.4 MHz, multiple carriers can be used, and at 5 MHz, one carrier can be used, When the second wireless communication system does not use the frequency band, the base station performs wireless communication using a carrier with a bandwidth of 5 MHz of the first wireless communication system.

6. A wireless communication system, which is a first wireless communication system that shares the same frequency band with a second wireless communication system. As the communication method of the first wireless communication system, the base station uses TD-LTE to communicate with a wireless terminal, and the communication method of the first wireless communication system is different from that of the second wireless communication system, At least 1.4 MHz and 5 MHz exist in the bandwidth of the first wireless communication system, At 1.4 MHz, multiple carriers can be used, and at 5 MHz, one carrier can be used, When the second wireless communication system does not use the frequency band, the base station performs wireless communication using a carrier with a bandwidth of 5 MHz of the first wireless communication system.

Images