Radio repeater, radio repeater method, and computer program

Abstract

To improve a stability of an operation of a radio repeater in a TDD system radio system.SOLUTION: A radio repeater that relays a signal transmitted and received between a terminal and a base station in a TDD system radio system, comprises: a downlink received power change detection part that detects a change of a received power of a radio signal received by a base station corresponding antenna; an uplink received power change detection part that detects the change of the received power of the radio signal received by a terminal corresponding antenna; and a control part that performs switching control of a downlink direction and an uplink direction in the TDD system on the basis of a result of a detection of the change of the received power of the radio signal by the downlink received power change detection part. The control part changes the switching control on the basis of the result of the detection of the change of the received power of the radio signal by the uplink received power change detection part.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a wireless repeater, a wireless repeating method, and a computer program. [Background technology]

[0002] Conventionally, a wireless repeater that relays signals transmitted and received between a terminal and a base station in a TDD (Time Division Duplex) wireless system is known (see, for example, Patent Document 1). In a TDD wireless system, signals from the terminal to the base station (uplink) and signals from the base station to the terminal (downlink) use the same frequency, so that bidirectional communication is performed between the terminal and the base station by switching between an uplink transmission period and a downlink transmission period in a time division manner. In a TDD wireless system, a wireless repeater receives and amplifies each of the uplink and downlink signals before transmitting them.

[0003] In the technology described in Patent Document 1, in a wireless repeater device, a TDD control means 101 detects the timing of reception from and the timing of transmission to an upstream wireless device based on a received signal (output of bandpass filters 8a to 8c) from an upstream wireless device (a wireless base station or another wireless repeater device) located upstream of the relay path, and based on these timings, controls the switching of a time switch 3 so that the upstream wireless device recognizes that it is communicating directly wirelessly with a downstream wireless device (another wireless repeater device or a wireless terminal device) located downstream of the relay path, thereby realizing TDD with the upstream wireless device (paragraph

[0029] , Figure 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2011-139157 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the technology described in the above-mentioned Patent Document 1 has the following problems. In a TDD wireless system, when multiple wireless repeaters are installed in close proximity, a wireless repeater A that newly starts synchronization (initial synchronization) in the TDD system receives both a downlink wireless signal transmitted from a base station and an uplink wireless signal relayed and transmitted from another wireless repeater B that has already started relaying. In this case, since the wireless repeater A has not yet completed initial synchronization, it cannot determine whether the wireless signal it has received is a downlink wireless signal from a base station or an uplink wireless signal from the wireless repeater B. For this reason, when receiving an uplink wireless signal from the wireless repeater B, the wireless repeater A erroneously recognizes that it has received a downlink wireless signal from a base station, and thus erroneously detects the uplink transmission period and the downlink transmission period of the TDD system. This may cause the operation of the wireless repeater to become unstable.

[0006] The present invention has been made in consideration of the above circumstances, and an object of the present invention is to improve the stability of operation of a wireless repeater in a TDD wireless system. [Means for solving the problem]

[0007] One aspect of the present invention is a wireless repeater that relays signals transmitted and received between a terminal and a base station in a TDD (Time Division Duplex) wireless system, and includes a base station compatible antenna for receiving a downlink wireless signal transmitted from the base station in a downlink direction from the base station to the terminal, a terminal compatible antenna for receiving an uplink wireless signal transmitted from the terminal in an uplink direction from the terminal to the base station, a downlink received power change detection unit for detecting a change in the received power of the wireless signal received by the base station compatible antenna, an uplink received power change detection unit for detecting a change in the received power of the wireless signal received by the terminal compatible antenna, and a control unit that performs switching control between the downlink and uplink directions of the TDD system based on a result of detection of a change in the received power of the wireless signal by the downlink received power change detection unit, and the control unit changes the switching control based on a result of detection of a change in the received power of the wireless signal by the uplink received power change detection unit. One aspect of the present invention is a wireless repeater, wherein the control unit determines a downlink transmission period of the TDD method based on a result of detection of a change in the received power of the wireless signal by the downlink received power change detection unit, and changes the downlink transmission period of the TDD method, which is a result of the determination, to an uplink transmission period of the TDD method based on a result of detection of a change in the received power of the wireless signal by the uplink received power change detection unit. One aspect of the present invention is a wireless repeater in which, in the above-mentioned wireless repeater, the control unit determines a slot width of the received signal based on a result of detection of a change in the received power of the wireless signal by the downlink received power change detection unit, and determines a downlink or uplink transmission period of the TDD method based on the determined slot width of the received signal. One aspect of the present invention is a wireless repeater in which the control unit determines whether or not an uplink transmission period of the TDD method can be detected based on a result of detection of a change in the received power of a radio signal by the uplink received power change detection unit, and changes the switching control when the uplink transmission period of the TDD method cannot be detected.

[0008] One aspect of the present invention is a wireless repeater that relays signals transmitted and received between a terminal and a base station in a TDD (Time Division Duplex) wireless system, the wireless repeater comprising a base station compatible antenna for receiving a downlink wireless signal transmitted from the base station in a downlink direction from the base station to the terminal, a terminal compatible antenna for receiving an uplink wireless signal transmitted from the terminal in an uplink direction from the terminal to the base station, a downlink received power change detection unit for detecting a change in the received power of the wireless signal received by the base station compatible antenna, and an uplink received power change detection unit for detecting a change in the received power of the wireless signal received by the terminal compatible antenna, and a wireless repeating method executed by the wireless repeater, the wireless repeater including a control step of performing switching control between the downlink and uplink directions of the TDD system based on a result of detection of a change in the received power of the wireless signal by the downlink received power change detection unit, and a step of changing the switching control based on a result of detection of a change in the received power of the wireless signal by the uplink received power change detection unit.

[0009] One aspect of the present invention is a computer program for causing a computer of the wireless repeater to execute a control step of switching between the downlink and uplink directions of the TDD system based on the result of detection of the change in the received power of the wireless signal by the downlink received power change detection unit, and a step of changing the switching control based on the result of detection of the change in the received power of the wireless signal by the uplink received power change detection unit, in which a wireless repeater that relays signals transmitted and received between a terminal and a base station in a TDD (Time Division Duplex) wireless system comprises a base station compatible antenna for receiving a downlink wireless signal transmitted from the base station in the downlink direction from the base station to the terminal, a terminal compatible antenna for receiving an uplink wireless signal transmitted from the terminal in the uplink direction from the terminal to the base station, a downlink received power change detection unit for detecting a change in the received power of the wireless signal received by the base station compatible antenna, and Effect of the Invention

[0010] According to the present invention, it is possible to obtain an effect of improving the stability of the operation of a wireless repeater in a TDD wireless system. [Brief description of the drawings]

[0011] [Figure 1] 1 is a block diagram showing an example of the configuration of a wireless system according to an embodiment; [Diagram 2] FIG. 2 is a block diagram showing a configuration example of a wireless repeater according to an embodiment. [Diagram 3] FIG. 2 is a diagram illustrating an example of the configuration of a TDD frame according to an embodiment. [Figure 4] 1 is a flowchart showing a first example of a procedure of a wireless relay method according to an embodiment. [Diagram 5] 1 is a first example of a switching timing chart according to an embodiment. [Figure 6] 10 is a flowchart showing a second example of a procedure of a wireless relay method according to an embodiment. [Figure 7] 13 is a second example of a switching timing chart according to an embodiment. [Figure 8] FIG. 2 is a block diagram illustrating an example of a wireless repeater according to an embodiment. [Figure 9] FIG. 4 is a block diagram showing an example of the configuration of a control unit according to an embodiment. [Figure 10] FIG. 1 is a schematic configuration diagram illustrating an example of a wireless system according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a block diagram showing a configuration example of a wireless system according to an embodiment. The wireless system 1 shown in Fig. 1 is a TDD (Time Division Duplex) system. Therefore, in the wireless system 1, an uplink wireless signal (uplink wireless signal) UL from a terminal UE (UE_1, UE_2) to a base station BS and a downlink wireless signal (downlink wireless signal) DL from the base station BS to the terminal UE use the same frequency, and a transmission period in the uplink direction and a transmission period in the downlink direction are switched in a time division manner to perform bidirectional communication between the terminal UE and the base station BS.

[0013] In the wireless system 1, the wireless repeaters 10 (10_1, 10_2) receive and amplify an uplink wireless signal UL and a downlink wireless signal DL, respectively, and then transmit them. Note that the frequency band used between the base station BS and the wireless repeater 10 and the frequency band used between the terminals UE (UE_1, UE_2) and the wireless repeater 10 may be the same frequency band or different frequency bands.

[0014] The frequency used between the terminal UE_1 and the wireless repeater 10_1 is different from the frequency used between the terminal UE_2 and the wireless repeater 10_2. As a result, radio interference does not occur between the terminal UE_1 and the wireless repeater 10_1 and between the terminal UE_2 and the wireless repeater 10_2. When the same frequency is used between the terminal UE_1 and the wireless repeater 10_1 and between the terminal UE_2 and the wireless repeater 10_2, signals are separated by the directivity of an antenna to prevent mutual interference from occurring between the terminal UE_1 and the wireless repeater 10_1 and between the terminal UE_2 and the wireless repeater 10_2.

[0015] On the other hand, the same frequency is used between the wireless repeater 10_1 and the base station BS and between the wireless repeater 10_2 and the base station BS. Therefore, when the wireless repeater 10_1 and the wireless repeater 10_2 are installed close to each other, for example, as shown in Fig. 1, leakage of a wireless signal from the wireless repeater 10_2 to the wireless repeater 10_1 occurs. This point will be described.

[0016] In the wireless system 1 illustrated in FIG. 1, the wireless repeater 10_1 and the wireless repeater 10_2 are installed close to each other. For this reason, for example, a situation occurs in which an uplink wireless signal relayed and transmitted from the wireless repeater 10_2 is received by the wireless repeater 10_1 after being routed around. In this case, when the wireless repeater 10_2 has already started a relaying operation, the wireless repeater 10_1 newly starts synchronization (initial synchronization) in the TDD system. The wireless repeater 10_1 newly starts synchronization (initial synchronization) in the TDD system receives both the downlink wireless signal transmitted from the base station BS and the uplink wireless signal relayed and transmitted from the wireless repeater 10_2 that has already started a relaying operation. Then, since the wireless repeater 10_1 has not yet completed the initial synchronization, it cannot determine whether the wireless signal it has received is a downlink wireless signal from the base station BS or an uplink wireless signal from the wireless repeater 10_2. Therefore, when receiving an uplink radio signal from the wireless repeater 10_2, the wireless repeater 10_1 erroneously recognizes that it has received a downlink radio signal from the base station BS, and thereby erroneously detects the uplink transmission period and the downlink transmission period of the TDD system. As a result, synchronization (initial synchronization) of the TDD system is not correctly achieved, and the operation of the wireless repeater 10_1 may become unstable. Therefore, in this embodiment, even if the wireless repeater 10_1 erroneously detects the uplink transmission period and the downlink transmission period of the TDD system, the erroneous detection is discriminated, thereby correcting the uplink transmission period and the downlink transmission period of the TDD system in the wireless repeater 10_1.

[0017] 2 is a block diagram showing an example of the configuration of a wireless repeater according to the present embodiment. In FIG. 2, the wireless repeater 10 includes a base station corresponding antenna 11, a terminal corresponding antenna 12, a downlink relay processing unit 13, an uplink relay processing unit 14, TDD switching units SW1 and SW2, and a control unit 20.

[0018] The base station corresponding antenna 11 is an antenna for receiving a downstream radio signal transmitted from the base station BS and transmitting an upstream radio signal toward the base station BS. The base station corresponding antenna 11 can also receive an upstream radio signal transmitted from another radio repeater 10 toward the base station BS. Therefore, the base station corresponding antenna 11 may receive an upstream radio signal transmitted from another radio repeater 10 installed nearby as shown in FIG. 1.

[0019] The terminal corresponding antenna 12 is an antenna for receiving an uplink radio signal transmitted from the terminal UE, and for transmitting a downlink radio signal to the terminal UE.

[0020] The downstream relay processing unit 13 amplifies the radio signal received via the base station corresponding antenna 11 and then transmits it via the terminal corresponding antenna 12. The downstream relay processing unit 13 also detects changes in the reception power of the radio signal received by the base station corresponding antenna 11. The downstream relay processing unit 13 outputs downstream reception power change information B that indicates changes in the reception power of the radio signal received by the base station corresponding antenna 11. The downstream relay processing unit 13 corresponds to a downstream reception power change detection unit.

[0021] The uplink relay processing unit 14 amplifies the radio signal received via the terminal corresponding antenna 12 and then transmits it via the base station corresponding antenna 11. The uplink relay processing unit 14 also detects changes in the reception power of the radio signal received by the terminal corresponding antenna 12. The uplink relay processing unit 14 outputs uplink reception power change information A that indicates changes in the reception power of the radio signal received by the terminal corresponding antenna 12. The uplink relay processing unit 14 corresponds to the uplink reception power change detection unit.

[0022] The TDD switching unit SW1 switches whether the base station corresponding antenna 11 is connected to the downlink relay processing unit 13 or the uplink relay processing unit 14 in accordance with a switching control signal C. The switching control signal C is output from the control unit 20. The control unit 20 generates the switching control signal C based on the detection results of the uplink transmission period and the downlink transmission period of the TDD system.

[0023] When the TDD switching unit SW1 selects the downstream relay processing unit 13, the base station corresponding antenna 11 and the downstream relay processing unit 13 are connected. As a result, the downstream relay processing unit 13 receives a radio signal via the base station corresponding antenna 11. To be precise, this connection is a connection during a downstream transmission period in the TDD system.

[0024] However, before synchronization (initial synchronization) of the TDD system is correctly established, there is a possibility that the uplink transmission period and downlink transmission period of the TDD system may not be correctly detected by the control unit 20. For this reason, even if the TDD switching unit SW1 selects the downlink relay processing unit 13 in accordance with the switching control signal C, the radio signal that the downlink relay processing unit 13 receives via the base station corresponding antenna 11 may be a downlink radio signal transmitted from the base station BS or an uplink radio signal transmitted from another radio repeater 10 to the base station BS, since it may be a downlink transmission period or an uplink transmission period of the TDD system.

[0025] On the other hand, when the TDD switching unit SW1 selects the uplink relay processing unit 14, the base station corresponding antenna 11 is connected to the uplink relay processing unit 14. As a result, the uplink relay processing unit 14 transmits an uplink wireless signal via the base station corresponding antenna 11.

[0026] The TDD switching section SW2 switches between connecting the terminal corresponding antenna 12 to the downstream relay processing section 13 or the upstream relay processing section 14 in accordance with a switching control signal C.

[0027] When the TDD switching unit SW2 selects the downlink relay processing unit 13, the terminal corresponding antenna 12 is connected to the downlink relay processing unit 13. As a result, the downlink relay processing unit 13 transmits a downlink radio signal via the terminal corresponding antenna 12.

[0028] On the other hand, when the TDD switching unit SW2 selects the upstream relay processing unit 14, the terminal corresponding antenna 12 is connected to the upstream relay processing unit 14. As a result, the upstream relay processing unit 14 receives an upstream radio signal via the terminal corresponding antenna 12.

[0029] The control unit 20 controls the switching of the TDD switching units SW1 and SW2. The control unit 20 receives uplink reception power change information A from the uplink relay processing unit 14. The control unit 20 also receives downlink reception power change information B from the downlink relay processing unit 13.

[0030] The control unit 20 performs switching control between the downlink and uplink directions of the TDD system based on the result of detection of a change in the reception power of the radio signal by the downlink relay processing unit 13 (downlink reception power change detection unit) (downlink reception power change information B). The control unit 20 changes the switching control between the downlink and uplink directions of the TDD system based on the result of detection of a change in the reception power of the radio signal by the uplink relay processing unit 14 (uplink reception power change detection unit) (uplink reception power change information A).

[0031] Specifically, when starting new synchronization (initial synchronization) in the TDD system, the control unit 20 first connects the base station compatible antenna 11 to the downlink relay processing unit 13 using the TDD switching unit SW1, detects the uplink transmission period and the downlink transmission period of the TDD system based on the downlink reception power change information B, and generates a switching control signal C for switching the uplink transmission period and the downlink transmission period of the TDD system based on this detection result (first detection result). In accordance with this switching control signal C, the TDD switching units SW1 and SW2 each perform a switching operation.

[0032] Next, the control unit 20 judges whether or not the uplink transmission period of the TDD system can be detected based on the uplink reception power change information A. If the result of this judgment is that the uplink transmission period of the TDD system can be detected, the first detection result is correct, that is, the uplink transmission period and the downlink transmission period of the TDD system have been correctly detected. Therefore, the control unit 20 continues to generate the switching control signal C using the current generation method of the switching control signal C based on the first detection result.

[0033] On the other hand, if the result of the determination is that the upstream transmission period of the TDD system cannot be detected, the first detection result is incorrect, that is, the upstream transmission period and the downstream transmission period of the TDD system have not been detected correctly. Therefore, the control unit 20 changes the current method of generating the switching control signal C.

[0034] Fig. 3 is a diagram showing an example of the configuration of a TDD frame. Fig. 3 shows a TDD frame used in the 3.5 GHz band of an LTE (Long Term Evolution) system, a TDD frame used in the 3.7 GHz band of a fifth generation mobile communication system (5G), and a TDD frame used in the 28 GHz band of a fifth generation mobile communication system (5G). All three types of TDD frames shown in Fig. 3 have a frame period (frame cycle) of 5 mS (5 milliseconds).

[0035] The configuration of a TDD frame used in the wireless system 1 is preset in the wireless repeater 10. When the wireless system 1 is, for example, a TDD scheme in the 3.5 GHz band of the LTE system, the configuration of a TDD frame in the 3.5 GHz band of the LTE system shown in FIG. 3 is preset in the wireless repeater 10.

[0036] The control unit 20 generates a switching control signal C based on a TDD frame configuration (periodicity of each transmission period of a downlink radio signal and an uplink radio signal) preset in the wireless repeater 10. The control unit 20 repeatedly generates the same switching control signal C with a frame period based on the TDD frame configuration preset in the wireless repeater 10.

[0037] Next, the operation of the wireless repeater 10 at the time of initial synchronization will be described.

[0038] [Example 1 of initial synchronization] An operation example 1 at the time of initial synchronization of the wireless repeater 10 according to the present embodiment will be described with reference to Fig. 4 and Fig. 5. Fig. 4 is a flowchart showing an example 1 of the procedure of the wireless repeating method according to the present embodiment. Fig. 5 is an example 1 of a switching timing chart according to the present embodiment.

[0039] In the operation example 1 at the time of initial synchronization, first, the control unit 20 judges the downlink transmission period of the TDD method based on the result of detection of the change in the reception power of the radio signal by the downlink relay processing unit 13 (downlink reception power change detection unit) (downlink reception power change information B), and performs switching control between the downlink and uplink directions of the TDD method based on the result of this judgment (initial switching timing detection phase). Next, the control unit 20 judges whether or not the uplink transmission period of the TDD method can be detected based on the result of detection of the change in the reception power of the radio signal by the uplink relay processing unit 14 (uplink reception power change detection unit) (uplink reception power change information A). Next, if the result of this judgment is that the uplink transmission period of the TDD method cannot be detected, the control unit 20 changes the downlink transmission period of the TDD method, which is the result of the judgment in the initial switching timing detection phase, to the uplink transmission period of the TDD method, and performs switching control between the downlink and uplink directions of the TDD method (timing correction phase). This will be described in detail below.

[0040] (Step S1) The control unit 20 connects the base station corresponding antenna 11 and the downlink relay processing unit 13 by the TDD switching unit SW1.

[0041] (Step S2) The control unit 20 attempts to detect the start or end timing of a reception slot based on the downlink reception power change information B. This timing detection may be detection of the rising timing of the reception signal or detection of the falling timing of the reception signal.

[0042] (Step S3) The control unit 20 judges whether the start or end timing of the receiving slot has been detected by the trial of step S2. If the start or end timing of the receiving slot has been detected, the process proceeds to step S4. On the other hand, if the start or end timing of the receiving slot cannot be detected, step S2 is repeated.

[0043] (Step S4) The control unit 20 sets the timing of the uplink transmission period and the downlink transmission period of the TDD frame by setting the timing detected in step S3 in the preset TDD frame configuration as the timing of the downlink transmission period. The control unit 20 generates a switching control signal C for switching between the uplink transmission period and the downlink transmission period of the TDD system based on the timing of the uplink transmission period and the downlink transmission period of the TDD frame that it has set. In accordance with this switching control signal C, the TDD switching units SW1 and SW2 each perform a switching operation.

[0044] Here, if the timing of the uplink transmission period and the timing of the downlink transmission period of the TDD frame set in step S4 are correct, the switching between the uplink and downlink transmission periods of the TDD system is performed correctly. Therefore, the downlink radio signal transmitted from the base station BS reaches the terminal UE via the radio repeater 10 and is received during the downlink transmission period of the TDD system. The terminal UE obtains the timing of the uplink transmission period of the TDD system by demodulating the received downlink radio signal, and transmits the uplink radio signal at the timing of the obtained uplink transmission period. Therefore, if the radio repeater 10 can detect the uplink radio signal transmitted from the terminal UE, it can be determined that the timing of the uplink transmission period and the downlink transmission period of the TDD frame set in step S4 are correct.

[0045] On the other hand, if the timing of the uplink transmission period and the timing of the downlink transmission period of the TDD frame set in step S4 are incorrect, the switching between the uplink and downlink transmission periods of the TDD system is not performed correctly. In this case, the radio repeater 10 cannot detect the uplink radio signal from the terminal UE, and therefore it can be determined that the timing of the uplink transmission period and the downlink transmission period of the TDD frame set in step S4 are incorrect.

[0046] (Step S5) The control unit 20 attempts to detect the start or end timing of a reception slot based on the uplink reception power change information A. This timing detection may be detection of the rising timing of the reception signal or detection of the falling timing of the reception signal.

[0047] (Step S6) The control unit 20 starts a timer. The timeout period of this timer may be any period. For example, an appropriate timeout period may be set according to the allowable time for initial synchronization.

[0048] (Step S7) The control unit 20 determines whether or not a received signal has been detected at the timing of the upstream transmission period of the TDD frame set in step S4.

[0049] If the result of the judgment in step S7 is that a received signal is detected (step S7, YES), the timing of the uplink transmission period and the timing of the downlink transmission period of the TDD frame set in step S4 are correct, and the uplink radio signal transmitted from the terminal UE can be received at the timing of the uplink transmission period. In other words, initial synchronization is successful. As a result, the control unit 20 maintains the current TDD frame timing setting (the timing of the uplink transmission period and the downlink transmission period of the TDD frame set in step S4), and continues to generate the switching control signal C based on this setting (step S8).

[0050] On the other hand, if the result of the judgment in step S7 is that a received signal cannot be detected (step S7, NO), and the timer has timed out (step S9, YES), the process proceeds to step S10; if the timer has not yet timed out (step S9, NO), the process returns to step S7.

[0051] (Step S10) The control unit 20 resets the timing of the uplink transmission period and the downlink transmission period of the TDD frame by setting the timing detected in step S3 in the preset TDD frame configuration as the timing of the uplink transmission period. That is, the timing of the downlink transmission period is reset by setting the timing of the uplink transmission period to the timing of the uplink transmission period for the TDD frame set in step S4. The control unit 20 generates a switching control signal C for switching the uplink transmission period and the downlink transmission period of the TDD system based on the reset timing of the uplink transmission period and the downlink transmission period of the TDD frame. In accordance with this switching control signal C, the TDD switching units SW1 and SW2 each perform a switching operation.

[0052] (Step S11) The control unit 20 attempts to detect the start or end timing of a reception slot based on the uplink reception power change information A. This timing detection may be detection of the rising timing of the reception signal or detection of the falling timing of the reception signal.

[0053] (Step S12) The control unit 20 starts a timer. The timeout period of this timer may be any period. For example, an appropriate timeout period may be set according to the allowable time for initial synchronization.

[0054] (Step S13) The control unit 20 determines whether or not a received signal has been detected at the timing of the upstream transmission period of the TDD frame reset in step S10.

[0055] If the result of the judgment in step S13 is that a received signal is detected (step S13, YES), the timing of the uplink transmission period and the timing of the downlink transmission period of the TDD frame reset in step S10 are correct, and the uplink radio signal transmitted from the terminal UE can be received at the timing of the uplink transmission period. In other words, initial synchronization is successful. As a result, the control unit 20 maintains the current TDD frame timing setting (the timing of the uplink transmission period and the downlink transmission period of the TDD frame reset in step S10) and continues to generate the switching control signal C based on this setting (step S14).

[0056] On the other hand, if the result of the judgment in step S13 is that the received signal cannot be detected (step S13, NO), and the timer times out (step S15, YES), the process returns to step S1 and the initial synchronization operation is restarted from the beginning (initial synchronization retry). If the timer has not yet timed out (step S15, NO), the process returns to step S13.

[0057] Fig. 5 shows an example of a switching timing chart according to the first operation example during initial synchronization. The example in Fig. 5 shows a case where the start or end timing of a receive slot is detected at the rising edge of a receive signal. The same can be applied to a case where the start or end timing is detected at the falling edge of a receive signal.

[0058] In FIG. 5, when an uplink radio signal transmitted from another radio repeater 10 is received by the base station corresponding antenna 11 with low received power (when there is little feedback), the timing of the uplink transmission period and the timing of the downlink transmission period of the TDD frame set in step S4 (state A1) are correct, and the uplink radio signal transmitted from the terminal UE is received at the timing of the uplink transmission period, so the radio repeater 10 continues relaying operation as is (state A2).

[0059] On the other hand, if the uplink radio signal transmitted from another radio repeater 10 is received by the base station corresponding antenna 11 with high reception power (large loop), the timing of the uplink transmission period and the timing of the downlink transmission period of the TDD frame set in step S4 (state A1) are incorrect, so that the uplink radio signal transmitted from the terminal UE cannot be received at the timing of the uplink transmission period, and the radio repeater 10 resets the timing of the uplink transmission period and the timing of the downlink transmission period of the TDD frame (state A3). If the uplink radio signal transmitted from the terminal UE can be received at the timing of the reset uplink transmission period as a result of this resetting, the radio repeater 10 continues the relay operation as it is (state A4).

[0060] [Example 2 of initial synchronization] An operation example 2 at the time of initial synchronization of the wireless repeater 10 according to the present embodiment will be described with reference to Fig. 6 and Fig. 7. Fig. 6 is a flowchart showing an example 2 of the procedure of the wireless repeating method according to the present embodiment. Fig. 7 is an example 2 of a switching timing chart according to the present embodiment.

[0061] In the operation example 2 at the time of initial synchronization, first, the control unit 20 judges the slot width of the received signal based on the result of detection of the change in the received power of the radio signal by the downlink relay processing unit 13 (downlink received power change detection unit) (downlink received power change information B), judges the transmission period of the downlink or uplink of the TDD method based on the result of the slot width judgment, and performs switching control between the downlink and uplink of the TDD method based on the judgment result of the transmission period (initial switching timing detection phase). Next, the control unit 20 judges whether or not the transmission period of the uplink of the TDD method can be detected based on the result of detection of the change in the received power of the radio signal by the uplink relay processing unit 14 (uplink received power change detection unit) (uplink received power change information A) (generation timing confirmation phase). This will be described in detail below.

[0062] (Step S31) The control unit 20 connects the base station corresponding antenna 11 and the downlink relay processing unit 13 by the TDD switching unit SW1.

[0063] (Step S32) The control unit 20 attempts to detect the slot width of the received signal based on the downlink received power change information B. This slot width detection may utilize the rising and falling timings of the received signal.

[0064] (Step S33) The control unit 20 judges whether or not the slot width has been detected by the trial in step S32. If the slot width has been detected, the process proceeds to step S34. On the other hand, if the slot width cannot be detected, step S32 is repeated.

[0065] (Step S34) The control unit 20 judges whether the slot width detected in step S33 is equal to the downlink transmission period of the TDD system. If the result of this judgment is that the slot width is equal to the downlink transmission period (step S34, YES), the process proceeds to step S35, and if not (step S34, NO), the process proceeds to step S36.

[0066] (Step S35) The control unit 20 sets the timing of the uplink transmission period and the downlink transmission period of the TDD frame by setting the timing of the slot width detected in step S33 in the preset TDD frame configuration as the timing of the downlink transmission period. The control unit 20 generates a switching control signal C for switching between the uplink transmission period and the downlink transmission period of the TDD system based on the timing of the uplink transmission period and the downlink transmission period of the set TDD frame. In accordance with this switching control signal C, the TDD switching units SW1 and SW2 each perform a switching operation.

[0067] (Step S36) The control unit 20 sets the timing of the uplink transmission period and the downlink transmission period of the TDD frame by setting the timing of the slot width detected in step S33 in the preset TDD frame configuration as the timing of the uplink transmission period. The control unit 20 generates a switching control signal C for switching between the uplink transmission period and the downlink transmission period of the TDD system based on the timing of the uplink transmission period and the downlink transmission period of the set TDD frame. In accordance with this switching control signal C, the TDD switching units SW1 and SW2 each perform a switching operation.

[0068] (Step S37) The control unit 20 attempts to detect the start or end timing of the reception slot based on the uplink reception power change information A. This timing detection may be detection of the rising timing of the reception signal or detection of the falling timing of the reception signal.

[0069] (Step S38) The control unit 20 starts a timer. The timeout period of this timer may be any period. For example, an appropriate timeout period may be set according to the allowable time for initial synchronization.

[0070] (Step S39) The control unit 20 determines whether or not a received signal has been detected at the timing of the upstream transmission period of the TDD frame set in step S35 or step S36.

[0071] If the result of the judgment in step S39 is that a received signal is detected (step S39, YES), the timing of the uplink transmission period and the timing of the downlink transmission period of the TDD frame set in step S35 or step S36 are correct, and the uplink radio signal transmitted from the terminal UE can be received at the timing of the uplink transmission period. In other words, initial synchronization is successful. As a result, the control unit 20 maintains the current TDD frame timing setting (the timing of the uplink transmission period and the timing of the downlink transmission period of the TDD frame set in step S35 or step S36), and continues to generate the switching control signal C based on this setting (step S41).

[0072] On the other hand, if the result of the judgment in step S39 is that the received signal cannot be detected (step S39, NO), and the timer times out (step S40, YES), the process returns to step S31 and the initial synchronization operation is restarted from the beginning (initial synchronization retry). If the timer has not yet timed out (step S40, NO), the process returns to step S39.

[0073] Fig. 7 shows an example of a switching timing chart according to the operation example 2 at the time of initial synchronization. In Fig. 7, when an uplink wireless signal transmitted from another wireless repeater 10 is received by the base station corresponding antenna 11 with low reception power (when the reception power is small), the timing of the uplink transmission period and the timing of the downlink transmission period of the TDD frame set in step S35 (state B2) are correct, and the uplink wireless signal transmitted from the terminal UE can be received at the timing of the uplink transmission period, so the wireless repeater 10 continues the relay operation as it is (state B3).

[0074] Furthermore, when an uplink radio signal transmitted from another radio repeater 10 is leaking and the received power at the base station corresponding antenna 11 is medium (when leaking), the timing of the uplink transmission period and the timing of the downlink transmission period of the TDD frame set in step S36 (state B2) are correct, and the uplink radio signal transmitted from the terminal UE can be received at the timing of the uplink transmission period, so the radio repeater 10 continues the relaying operation as is (state B3).

[0075] Furthermore, if an uplink radio signal transmitted from another radio repeater 10 is received by the base station-compatible antenna 11 with high reception power (large interference), the timing of the uplink transmission period and the timing of the downlink transmission period of the TDD frame set in step S36 (state B2) are correct, and the uplink radio signal transmitted from the terminal UE is received at the timing of the uplink transmission period, so the radio repeater 10 continues relaying operation as is (state B3).

[0076] In the examples of the switching timing charts in Figures 5 and 7 described above, all 14 symbols in the flexible (F) slot are shown as guard symbols, but the same is applicable even if downstream symbols or upstream symbols are assigned to the F slot, as long as they are consecutive with the downstream slot or upstream slot, respectively.

[0077] In addition, even if the symbol configuration within the F slot changes depending on the operation, it is possible to accommodate this by correcting the switching timing between the uplink and downlink directions in the TDD system using the moving average of the rising or falling timing of the downlink and uplink received signals.

[0078] Next, an example of the wireless repeater 10 according to the present embodiment will be described. Fig. 8 is a block diagram showing an example of the wireless repeater 10 according to the present embodiment. In Fig. 8, parts corresponding to those in Fig. 2 are given the same reference numerals.

[0079] In the wireless repeater 10 shown in Fig. 8, the radio frequency used on the base station side is different from the radio frequency used on the terminal side. The radio frequency used on the base station side is in the millimeter wave band. The radio frequency used on the terminal side is in the terahertz band. Therefore, the wireless repeater 10 receives the upstream wireless signal and the downstream wireless signal, converts the frequency of the signals, amplifies the signals, and then transmits them.

[0080] The base station compatible antenna (mmWANT) 11 is an antenna for receiving millimeter wave band radio signals transmitted from the base station BS, and for transmitting millimeter wave band radio signals to the base station BS.

[0081] The terminal corresponding antenna (THzBFANT) 12 is an antenna for receiving a terahertz band radio signal transmitted from the terminal UE, and for transmitting a terahertz band radio signal to the terminal UE.

[0082] The downstream relay processing unit 13 (coupler 13-1, variable attenuator 13-2, upconverter 13-3, bandpass filter 13-4, power amplifier 13-5) frequency converts (upconverts) the millimeter wave band radio signal received via the base station compatible antenna 11 to the terahertz band, amplifies it, and then transmits it via the terminal compatible antenna 12.

[0083] The upstream relay processing unit 14 (coupler 14-1, variable attenuator 14-2, downconverter 14-3, bandpass filter 14-4, power amplifier 14-5) frequency converts (downconverts) the terahertz band radio signal received via the terminal-compatible antenna 12 to the millimeter wave band, amplifies it, and then transmits it via the base station-compatible antenna 11.

[0084] The PLL_15 generates a clock signal for frequency conversion. The clock signal generated by the PLL_15 is supplied to the up-converter 13-3 and the down-converter 14-3.

[0085] The TDD switching unit (TDD SW) SW1 switches whether the base station corresponding antenna 11 is connected to the downstream relay processing unit 13 (the input unit of the coupler 13-1) or to the upstream relay processing unit 14 (the output unit of the power amplifier 14-5) in accordance with a switching control signal C output from the control unit 20.

[0086] The TDD switching unit (TDD SW) SW2 switches whether the terminal corresponding antenna 12 is connected to the downstream relay processing unit 13 (the output unit of the power amplifier 13-5) or to the upstream relay processing unit 14 (the input unit of the coupler 14-1) in accordance with a switching control signal C output from the control unit 20.

[0087] The control unit 20 receives upstream reception power change information A from the upstream relay processing unit 14 (branching unit of coupler 14-1). The control unit 20 also receives downstream reception power change information B from the downstream relay processing unit 13 (branching unit of coupler 13-1). The control unit 20 generates the switching control signal C as described above. The switching control signal C is output to the TDD switching units SW1 and SW2.

[0088] Fig. 9 is a block diagram showing a configuration example of the control unit 20 shown in Fig. 8. Of the units shown in Fig. 8, the function of the dashed line portion 220 may be realized by a microcomputer included in the wireless repeater 10 executing software (computer program), or may be realized by hardware.

[0089] The upstream reception power change information A is input to the detector 201a. This upstream reception power change information A is a terahertz band radio signal branched by the coupler 14-1 of the upstream relay processing unit 14. The detector 201a detects the upstream reception power change information A (terahertz band radio signal) to obtain the upstream reception signal level.

[0090] Downstream reception power change information B is input to detector 201b. This downstream reception power change information B is a millimeter waveband radio signal branched by coupler 13-1 of downstream relay processing unit 13. Detector 201b detects the downstream reception power change information B (millimeter waveband radio signal) to obtain the downstream reception signal level.

[0091] 8, a detector may be used so that the received signal levels are input to the control unit 20 as the received power change information A and B. In this case, the detectors 201a and 201b are not required.

[0092] The level adjuster 202a adjusts the signal level by amplifying or attenuating the signal so that the average value of the uplink reception signal level obtained by the detector 201a becomes a predetermined value. This makes it possible to correct the change in the uplink reception signal level according to the distance between the wireless repeater 10 and the terminal UE.

[0093] The level adjuster 202b adjusts the signal level by amplifying or attenuating the signal so that the average value of the downstream reception signal level obtained by the detector 201b becomes a predetermined value. This makes it possible to correct the change in the downstream reception signal level according to the distance between the wireless repeater 10 and the base station BS.

[0094] The level comparator 203a compares the level of the uplink reception signal after the level correction with a predetermined uplink level judgment threshold, and outputs an uplink level judgment signal indicating whether the uplink reception signal level is higher than the uplink level judgment threshold. The uplink level judgment threshold is a value selected from values ​​between the signal level of the uplink radio signal in a signal-present period and the signal level of the no-signal period. The reception power of the uplink radio signal transmitted from the terminal UE changes from weak power to strong power at the start timing of the transmission period of the uplink radio signal of the TDD frame, and changes from strong power to weak power at the end timing of the transmission period of the uplink radio signal of the TDD frame. The uplink level judgment threshold is a threshold for detecting this change (presence or absence of an uplink radio signal).

[0095] The level comparator 203b compares the level of the downlink reception signal after the level correction with a predetermined downlink level judgment threshold, and outputs a downlink level judgment signal indicating whether the downlink reception signal level is higher than the downlink level judgment threshold. The downlink level judgment threshold is a value selected from values ​​between the signal level of a signal period and the signal level of a no-signal period for the downlink radio signal. The reception power of the downlink radio signal transmitted from the base station BS changes from weak power to strong power at the start timing of the transmission period of the downlink radio signal of the TDD frame, and changes from strong power to weak power at the end timing of the transmission period of the downlink radio signal of the TDD frame. The downlink level judgment threshold is a threshold for detecting this change (the presence or absence of a downlink radio signal).

[0096] Each level judgment signal output by each level comparator 203a, 203b may be a signal equivalent to a digital signal of "1: above level judgment threshold" and "0: below level judgment threshold". Also, by providing two types of threshold levels for each level judgment threshold, level judgment with hysteresis characteristics may be performed. This makes it possible to suppress errors in the output of the level comparator caused by noise contained in the received signal level.

[0097] The upward level judgment signal output from the level comparator 203 a and the downward level judgment signal output from the level comparator 203 b are output to a switching timing detection section 222 .

[0098] The clock generator 210 generates a clock signal at an integer fraction of the minimum time step required for the TDD switching units SW1 and SW2 to switch the connection of the antennas 11 and 12 (switch the uplink and downlink transmission periods in the TDD system). The frequency of the clock signal corresponds to the count frequency.

[0099] Counter 221 counts the clock signal generated by clock generator 210. Counter 221 is reset for each frame period of the TDD frame. Therefore, counter 221 starts counting from an initial count value of "0", and when the count value reaches a count number corresponding to one period of the TDD frame, the count value is reset to the initial value of "0" and then counting resumes.

[0100] For example, the frame period is 5 ms in the 3.5 GHz band TDD frame of the LTE system shown in Fig. 3. In this case, if the minimum time step for switching the connection destination of each of the antennas 11 and 12 by the TDD switching units SW1 and SW2 is 1 µS (1 microsecond), and the period of the clock signal generated by the clock generator 210 is 1 µS, that is, the clock oscillation frequency is 1 MHz (1 megaHz), the counter 221 counts from the count initial value "0" to the count end value "4999", and then is reset to the count initial value "0" and restarts counting.

[0101] The count value of the counter 221 is input to the switching timing detection unit 222. Furthermore, each level determination signal output from each level comparator 203a, 203b is input to the switching timing detection unit 222. Here, for convenience of explanation, each level determination signal is "1: exceeding level determination threshold" or "0: equal to or less than level determination threshold."

[0102] The switching timing detector 222 stores the count value (uplink start timing count value) at the timing when the uplink level determination signal output from the level comparator 203a changes from "0" to "1." The count value at that timing (uplink start timing count value) indicates the start of the uplink transmission period.

[0103] Furthermore, the switching timing detector 222 stores the count value (uplink end timing count value) at the timing when the uplink level determination signal output from the level comparator 203a changes from "1" to "0." The count value at that timing (uplink end timing count value) indicates the end of the uplink transmission period.

[0104] The uplink end timing count value may be a value obtained by adding a count number corresponding to the length of the transmission period of the uplink radio signal to the uplink start timing count value. The length of the transmission period of the uplink radio signal is included in the configuration of the TDD frame preset in the radio repeater 10. The uplink start timing count value may be a value obtained by subtracting a count number corresponding to the length of the transmission period of the uplink radio signal from the uplink end timing count value.

[0105] The switching timing detector 222 stores the count value (downlink start timing count value) at the timing when the downstream level determination signal output from the level comparator 203b changes from "0" to "1." The count value at that timing (downlink start timing count value) indicates the start of the downstream transmission period.

[0106] Furthermore, the switching timing detector 222 stores the count value (downlink end timing count value) at the timing when the downstream level determination signal output from the level comparator 203b changes from "1" to "0." The count value at that timing (downlink end timing count value) indicates the end of the downstream transmission period.

[0107] The downlink end timing count value may be a value obtained by adding a count number corresponding to the length of the transmission period of the downlink radio signal to the downlink start timing count value. The length of the transmission period of the downlink radio signal is included in the configuration of the TDD frame preset in the wireless repeater 10. The downlink start timing count value may be a value obtained by subtracting a count number corresponding to the length of the transmission period of the downlink radio signal from the downlink end timing count value.

[0108] The switching timing detector 222 outputs the upward direction start timing count value, the upward direction end timing count value, the downward direction start timing count value, and the downward direction end timing count value to the switching control signal generator 223 .

[0109] Note that the average value of a predetermined number of times for each of the uplink start timing count value, the uplink end timing count value, the downlink start timing count value and the downlink end timing count value may be stored in the switching timing detection unit 222 and output to the switching control signal generation unit 223. This makes it possible to reduce the influence of timing fluctuations that occur in the output timing of each level determination signal from each level comparator 203a, 203b due to a decrease in the reception level, noise, fading, etc.

[0110] The count value of the counter 221 is input to the switching control signal generator 223. In addition, the switching control signal generator 223 receives an upward direction start timing count value, an upward direction end timing count value, a downward direction start timing count value, and a downward direction end timing count value output by the switching timing detector 222.

[0111] The switching control signal generator 223 generates a switching control signal C based on the count value of the counter 221, the upward direction start timing count value, the upward direction end timing count value, the downward direction start timing count value, and the downward direction end timing count value.

[0112] According to this embodiment, even if the wireless repeater 10 erroneously detects the uplink transmission period and the downlink transmission period of the TDD system, the erroneous detection can be identified and the uplink transmission period and the downlink transmission period of the TDD system can be corrected in the wireless repeater 10. This allows the synchronization (initial synchronization) of the TDD system to be correctly achieved, thereby providing the effect of improving the stability of the operation of the wireless repeater in the TDD system wireless system.

[0113] Furthermore, the wireless repeater 10 can realize switching between the uplink and downlink transmission periods in the TDD system by detecting changes in received power, which is smaller than that of a demodulation circuit, without using a complex and large-scale demodulation circuit. This contributes to making the wireless repeater 10 in the TDD wireless system 1 smaller, lighter, and more energy-efficient.

[0114] Furthermore, according to this embodiment, a plurality of wireless repeaters 10 can be installed in close proximity to each other and used.

[0115] Fig. 10 is a schematic diagram showing an example of a wireless system 1 according to this embodiment. In the wireless system 1 shown in Fig. 10, the radio frequency used on the base station side is different from the radio frequency used on the terminal side. The radio frequency used on the base station side is in the millimeter wave band. The radio frequency used on the terminal side is in the terahertz band.

[0116] In the wireless system 1 shown in FIG. 10, the wireless repeater 10 of FIG. 8 according to this embodiment can be mounted on various devices DVa, DVb, DVc, DVd, and DVe. Device DVa is glasses worn by a user (terminal user) of the terminal UE. Device DVb is a vehicle in which the terminal user rides. Device DVc is headphones worn by the terminal user. Device DVd is a wristwatch worn by the terminal user. Device DVe is a portable personal computer (PC) used by the terminal user.

[0117] The wireless repeater 10 is provided, for example, in both glasses (device DVa) worn by a terminal user and a wristwatch (device DVd) worn by the terminal user. In this case, the wireless repeater 10_1 of the glasses (device DVa) and the wireless repeater 10_2 of the wristwatch (device DVd) are installed in close proximity to each other and are in an operating state (state in FIG. 1). Therefore, as illustrated in FIG. 1, a wireless signal may leak from one wireless repeater 10 to the other wireless repeater 10. However, as described above, according to this embodiment, synchronization (initial synchronization) of the TDD method is correctly achieved, so that the wireless repeaters 10_1 and 10_2 installed in close proximity to each other operate stably.

[0118] The terminal UE includes an antenna 301 for transmitting and receiving a terahertz band radio signal, and a signal processing unit 302 for processing a received terahertz band signal. The signal processing unit 302 demodulates a terahertz band downstream radio signal received by the antenna 301 via a wireless repeater 10_1 provided in the glasses (device DVa) or a wireless repeater 10_2 provided in the wristwatch (device DVd) to detect a TDD frame, and transmits a terahertz band upstream radio signal by the antenna 301 during an upstream transmission period based on the detected TDD frame. A terahertz band link THz LINK is established between the terminal UE and the wireless repeater 10_1 provided in the glasses (device DVa) or the wireless repeater 10_2 provided in the wristwatch (device DVd).

[0119] The wireless repeater 10_1 in the glasses (device DVa) and the wireless repeater 10_2 in the watch (device DVd) transmit and receive upstream and downstream wireless signals in the millimeter wave band between the base station BS. The wireless repeater 10_1 in the glasses (device DVa) and the wireless repeater 10_2 in the watch (device DVd) receive the upstream and downstream wireless signals, respectively, frequency-convert and amplify them, and then transmit them. This allows the terminal UE and the base station BS to perform bidirectional communication in the TDD system via the wireless repeater 10_1 and the wireless repeater 10_2.

[0120] Here, for example, in small devices such as glasses (device DVa), headphones (device DVc), and wristwatches (device DVd), there are significant restrictions on the size, weight, battery capacity, and other factors of the equipment that can be mounted. For these small devices DVa, DVc, and DVd, there is a particular demand for the mounted wireless repeater 10 to be small, lightweight, and power-saving. This embodiment provides particularly significant effects when the wireless repeater 10 is mounted on such small devices DVa, DVc, and DVd.

[0121] In addition, for example, devices such as glasses (device DVa), headphones (device DVc), and wristwatches (device DVd) worn by terminal users can be installed in close proximity and used. This embodiment can also provide a particularly significant effect when the wireless repeater 10 is mounted on each of a plurality of devices that can be installed in close proximity and used.

[0122] This will, for example, make it possible to improve the overall service quality in wireless systems, thereby contributing to Goal 9 of the United Nations' Sustainable Development Goals (SDGs), which is to "Build resilient infrastructure, promote sustainable industrialization and foster innovation."

[0123] Although an embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes and the like that do not deviate from the gist of the present invention are also included.

[0124] Also, a computer program for implementing the functions of each of the above-mentioned devices may be recorded on a computer-readable recording medium, and the program recorded on the recording medium may be read into a computer system and executed. Note that the "computer system" referred to here may include hardware such as an OS and peripheral devices. Also, the "computer-readable recording medium" refers to a flexible disk, a magneto-optical disk, a ROM, a writable non-volatile memory such as a flash memory, a portable medium such as a DVD (Digital Versatile Disc), and a storage device such as a hard disk built into a computer system.

[0125] Furthermore, the term "computer-readable recording medium" includes a memory that holds a program for a certain period of time, such as a volatile memory (e.g., DRAM (Dynamic Random Access Memory)) inside a computer system that becomes a server or a client when a program is transmitted via a network such as the Internet or a communication line such as a telephone line. The above-mentioned program may be transmitted from a computer system that stores the program in a storage device or the like to another computer system via a transmission medium, or by a transmission wave in the transmission medium. Here, the "transmission medium" that transmits the program refers to a medium that has a function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line. The above-mentioned program may be a program for realizing part of the above-mentioned functions. Furthermore, the above-mentioned function may be realized in combination with a program already recorded in the computer system, that is, a so-called difference file (difference program). [Explanation of symbols]

[0126] 1...wireless system, UE...terminal, BS...base station, 10, 10_1, 10_2...wireless repeater, 11...base station compatible antenna, 12...terminal compatible antenna, 13...downstream relay processing unit, 14...upstream relay processing unit, SW1, SW2...TDD switching unit, 20...control unit, 201a, 201b...wave detector, 202a, 202b...level adjuster, 203a, 203b...level comparator, 210...clock generator, 221...counter, 222...switching timing detection unit, 223...switching control signal generation unit

Claims

1. A wireless repeater that relays signals transmitted and received between a terminal and a base station in a TDD (Time Division Duplex) wireless system, a base station corresponding antenna for receiving a downstream radio signal transmitted from the base station in a downstream direction from the base station to the terminal; a terminal corresponding antenna for receiving an uplink wireless signal transmitted from the terminal in an uplink direction from the terminal to the base station; a downstream reception power change detection unit for detecting a change in reception power of a wireless signal received by the base station corresponding antenna; an uplink reception power change detection unit for detecting a change in reception power of a radio signal received by the terminal corresponding antenna; a control unit that performs switching control between a downlink direction and an uplink direction of a TDD system based on a result of detection of a change in the reception power of a radio signal by the downlink reception power change detection unit; Equipped with the control unit changes the switching control based on a result of detection of a change in the reception power of the radio signal by the uplink reception power change detection unit. Radio repeater.

2. The control unit is determining a downlink transmission period in a TDD system based on a result of detection of a change in the reception power of the radio signal by the downlink reception power change detection unit; changing the downlink transmission period of the TDD system, which is the result of the determination, to an uplink transmission period of the TDD system, based on a result of detection of a change in the reception power of the radio signal by the uplink reception power change detection unit; 2. The wireless repeater according to claim 1.

3. The control unit is determining a slot width of a received signal based on a result of detection of a change in the received power of a radio signal by the downlink received power change detection unit; determining a transmission period in the downlink or uplink direction of the TDD system based on the determined slot width of the received signal; 2. The wireless repeater according to claim 1.

4. The control unit is determining whether or not a transmission period in the uplink direction of the TDD system can be detected based on a result of detection of a change in the reception power of the radio signal by the uplink reception power change detection unit; changing the switching control when an uplink transmission period of the TDD method cannot be detected; 4. A wireless repeater according to claim 1.

5. A wireless repeater that relays signals transmitted and received between a terminal and a base station in a TDD (Time Division Duplex) wireless system, a base station corresponding antenna for receiving a downstream radio signal transmitted from the base station in a downstream direction from the base station to the terminal; a terminal corresponding antenna for receiving an uplink wireless signal transmitted from the terminal in an uplink direction from the terminal to the base station; a downstream reception power change detection unit for detecting a change in reception power of a wireless signal received by the base station corresponding antenna; an uplink reception power change detection unit that detects a change in reception power of a radio signal received by the terminal corresponding antenna, A wireless relay method performed by the wireless repeater, a control step of switching between a downlink direction and an uplink direction of a TDD system based on a result of detection of a change in the reception power of a radio signal by the downlink reception power change detection unit; changing the switching control based on a result of detection of a change in reception power of a radio signal by the uplink reception power change detection unit; A wireless relay method comprising:

6. A wireless repeater that relays signals transmitted and received between a terminal and a base station in a TDD (Time Division Duplex) wireless system, a base station corresponding antenna for receiving a downstream radio signal transmitted from the base station in a downstream direction from the base station to the terminal; a terminal corresponding antenna for receiving an uplink wireless signal transmitted from the terminal in an uplink direction from the terminal to the base station; a downstream reception power change detection unit for detecting a change in reception power of a wireless signal received by the base station corresponding antenna; an uplink reception power change detection unit that detects a change in reception power of a radio signal received by the terminal corresponding antenna, A computer of the wireless repeater, a control step of switching between a downlink direction and an uplink direction of a TDD system based on a result of detection of a change in the reception power of a radio signal by the downlink reception power change detection unit; changing the switching control based on a result of detection of a change in reception power of a radio signal by the uplink reception power change detection unit; A computer program for executing the above.

Images