Repeater and control method for the repeater

Abstract

The present invention provides a repeater capable of relaying wireless signals with low latency, and a method for controlling the repeater. [Solution] The repeater is a repeater that converts and amplifies radio waves transmitted and received between a base station and a terminal device from a frequency division multiplexing scheme to a spatial division multiplexing scheme, and includes a first filter section that allows a first bandwidth frequency to pass through and extracts multiple single modulated waves by passing an electrical signal generated based on the received radio waves through a first SAW filter, which is provided in a plurality according to the number of frequency divisions of the received radio waves; and a second filter section that allows a second bandwidth frequency different from the first bandwidth to pass through, by passing the multiple single modulated waves that have passed through the first filter section through a second SAW filter connected in series with each of the plurality of first SAW filters.

Description

Technical Field

[0001] The present invention relates to a repeater and a method for controlling the repeater.

Background Art

[0002] Conventionally, a repeater that relays a wireless signal between a base station and a terminal device is known. For example, as a technique for improving the throughput of a repeater, a technique as described in Patent Document 1 is known.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Here, the repeater as described above is required to relay a wireless signal in a very short time within the CP (Cyclic Prefix) length. However, in recent years, the CP length has been gradually shortened, and a low-delay repeater is desired.

[0005] The present invention has been made in consideration of such circumstances, and an object thereof is to provide a repeater and a method for controlling the repeater capable of relaying a wireless signal with low latency.

Means for Solving the Problems

[0006] (1) One aspect of the present invention is a repeater that converts and amplifies radio waves transmitted and received between a base station and a terminal device from frequency division multiplexing (FDM) to space division multiplexing (SDM), and relays them, comprising: a first filter section that allows an electrical signal generated based on the received radio waves to pass through a plurality of first SAW (Surface Acoustic Wave) filters, which are provided in proportion to the number of frequency divisions of the received radio waves, thereby allowing frequencies of a first bandwidth to pass through and extracting a plurality of single modulated waves; and a second filter section that allows the plurality of single modulated waves that have passed through the first filter section to pass through a second SAW filter connected in series with each of the plurality of first SAW filters, thereby allowing frequencies of a second bandwidth different from the first bandwidth to pass through. (2) In addition, one aspect of the present invention further comprises a first variable control unit for varying the frequency of the first bandwidth and a second variable control unit for varying the frequency of the second bandwidth in the repeater described in (1) above. (3) In another aspect of the present invention, in the repeater described in (2) above, the first filter section is provided with resonant circuits before and after a plurality of first SAW filters, the second filter section is provided with resonant circuits before and after a plurality of second SAW filters, the first variable control unit varies the frequency of the first bandwidth by controlling the resonant circuits of the first filter section, and the second variable control unit varies the frequency of the second bandwidth by controlling the resonant circuits of the second filter section. (4) In addition, one aspect of the present invention further includes a MIMO (Multiple-Input Multiple-Output) stage control unit in any of the repeaters described in (1) to (3) above, which controls the number of radio waves transmitted by spatial multiplexing by disabling the operation of any of the multiple first SAW filters provided in the first filter unit and disabling the operation of any of the multiple second SAW filters provided in the second filter unit. (5) Another aspect of the present invention is a control method for a repeater that converts and amplifies radio waves transmitted and received between a base station and a terminal device from frequency division multiplexing (FDM) to space division multiplexing (SDM), the control method for a repeater comprising: a first filtering step in which an electrical signal generated based on a received radio wave passes through a plurality of first SAW filters, which are provided in proportion to the number of frequency divisions of the received radio wave, thereby allowing frequencies of a first bandwidth to pass through and extracting a plurality of single modulated waves; and a second signal filtering step in which the plurality of single modulated waves that have passed through the first filtering step pass through a second SAW filter, which is connected in series with each of the plurality of first SAW filters, thereby allowing frequencies of a second bandwidth different from the first bandwidth to pass through. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a repeater and a control method for the repeater that can relay wireless signals with low latency. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic diagram of a wireless system according to one embodiment. [Figure 2] Figure 1 schematically shows the functions of the repeater according to this embodiment. [Figure 3]The second figure schematically shows the functions of the repeater according to this embodiment. [Figure 4] This diagram illustrates the control of the frequency band by the repeater according to this embodiment. [Figure 5] This flowchart shows an example of a series of processing steps when detecting changes in the wireless environment using the terminal device according to this embodiment. [Figure 6] This flowchart shows an example of a series of processing steps when detecting changes in the wireless environment using the repeater according to this embodiment. [Figure 7] This flowchart shows an example of a series of processing steps when a base station according to this embodiment detects changes in the wireless environment. [Figure 8] This is a block diagram showing an example of the internal configuration of the repeater according to this embodiment. [Modes for carrying out the invention]

[0009] [Embodiment] A repeater and a control method for a repeater according to an aspect of the present invention will be described in detail below with reference to the attached drawings, with reference to preferred embodiments. It should be noted that the aspects of the present invention are not limited to these embodiments, and include various modifications and improvements. In other words, the components described below include those that are easily conceivable to those skilled in the art, and those that are substantially the same, and the components described below can be combined as appropriate. Furthermore, various omissions, substitutions, or modifications of components can be made without departing from the spirit of the present invention. Also, in the following drawings, the scale and number of components in each structure may differ from the scale and number of components in the actual structure in order to make each structure easier to understand.

[0010] In the following explanation, for the sake of clarity, terms and names defined in the 3GPP® LTE (3rd Generation Partnership Project Long Term Evolution) standard, etc., may be used. However, this embodiment is not limited by such terms and names and is applicable to systems based on other standards.

[0011] [Wireless System] Figure 1 is a diagram illustrating a schematic of a wireless system according to one embodiment. First, the schematic of the wireless system 1 according to this embodiment will be described with reference to Figure 1. The wireless system 1 comprises a terminal device 10, a base station 20, and a repeater 30. Typically, the wireless system 1 comprises multiple terminal devices 10, multiple base stations 20, and multiple repeaters 30. In the explanation given with reference to the same figure, for the sake of simplicity, an example will be given in which each component is present only once.

[0012] Terminal device 10 is a device used by the user. Specific examples of terminal device 10 include smartphones, tablet devices, wearable devices, etc. Terminal device 10 may also be referred to as UE (User Equipment), user equipment, mobile station, etc.

[0013] Base station 20 may also be called gNodeB (gNB), en-gNB, Next Generation-Radio Access Network (NG-RAN) node, eNB, low-power node, CU, DU, RU, gNB-DU, Remote Radio Head (RRH), Integrated Access and Backhaul / Backhauling (IAB) node, etc. Base station 20 may be permanently installed on the ground, for example. Base station 20 may be permanently installed on the ground by a telecommunications carrier, for example.

[0014] The base station 20 relays the repeater 30 and performs wireless communication with the terminal device 10. Although not shown in the figure, the base station 20 may directly perform wireless communication with the terminal device 10 without relaying the repeater 30.

[0015] The repeater 30 amplifies and relays signals such as control signals and data signals between the terminal device 10 and the base station 20. The repeater 30 can also be said to exist as a relay point for relaying information communication between the moving terminal device 10 and the base station 20. The repeater 30 amplifies and frequency-converts the signal received from the base station 20 and transmits it to the terminal device 10. Also, the base station 20 can amplify the signal received from the terminal device 10 and transmit it to the base station 20. The repeater 30 may be called a repeater, relay machine, relay device, relay station, etc.

[0016] The repeater 30 at least amplifies (strengthens) the signal during wireless signal relaying. The repeater 30 can also perform non-regenerative relaying by analog-processing the electrical signal.

[0017] The repeater 30 may exist as a moving body such as a drone, for example. Also, the repeater 30 may be fixed and used in a room. Also, the repeater 30 may be something that moves along with the movement of the user, such as a wearable device (wearable terminal device) like a smartwatch, smart glasses, headphones, wearable smart belt, etc.

[0018] In the present embodiment, when the communication rate of the communication line changes due to a change in the wireless environment, the wireless system 1 adjusts the number of stages (rank) of MIMO (Multiple-Input Multiple-Output) (Rank Adaptation) and optimizes the passband width of the digital modulation wave. Changes in the wireless environment include cases where the wireless environment deteriorates and cases where it improves.

[0019] When the base station 20 changes conditions such as the number of MIMO stages or the passband of the digital modulated wave, it notifies the repeater 30 of the changes using the relay control line. Upon receiving the information regarding the changes in conditions, the repeater 30 modifies the wireless communication settings.

[0020] Note that the relay control line is a different type of line from a normal communication line. As shown in the figure, the relay control line is installed between the base station 20 and the repeater 30.

[0021] [Functional configuration of the repeater] Next, an example of the functional configuration of the repeater 30 will be described with reference to Figures 2 to 4. The explanation using these figures will describe an example of converting a signal divided into four modulated waves using frequency division multiplexing (FDM) to space division multiplexing (SDM). However, this embodiment is not limited to this example and can be applied to signals divided into n modulated waves (where n is a natural number greater than or equal to 1) using frequency division multiplexing, such as 2 modulated wave division or 8 modulated wave division.

[0022] Figure 2 is a first diagram schematically showing the functions of the repeater according to this embodiment. First, the overall configuration of the repeater 30 will be described with reference to the same figure. The repeater 30 comprises a receiving antenna section 31, a splitting section 32, a MIMO stage control section 33, a first filter section 34, a first variable control section 35, a second filter section 36, a second variable control section 37, a transmitting antenna section 38, and a control section 39.

[0023] The receiving antenna unit 31 receives radio waves that have been divided in the frequency direction by a frequency multiplexing scheme. The radio waves received by the receiving antenna unit 31 are radio waves transmitted from either the terminal device 10 or the base station 20. The radio waves received by the receiving antenna unit 31 are frequency multiplexed waves and contain multiple signals in the frequency direction.

[0024] The division unit 32 divides the electrical signal generated based on the radio waves received by the receiving antenna unit 31 according to the number of frequency divisions of the received radio waves. In the illustrated example, since the radio waves received by the receiving antenna unit 31 are divided into four modulated waves, the division unit 32 divides the electrical signal into four parts. The division unit 32 outputs the four divided electrical signals to the first filter unit 34 as independent electrical signals.

[0025] The MIMO stage control unit 33 controls the number of MIMO stages. In the example shown in the figure, the case where the number of MIMO stages is a maximum of 4 is shown, but for example, the number of MIMO stages may be 8, 16, 32, or 64. In such cases, it is desirable to be able to vary the number of MIMO stages according to the communication conditions, etc. The MIMO stage control unit 33 has a function to vary the number of MIMO stages.

[0026] The first filter unit 34 allows a desired frequency to pass through by passing the electrical signal divided by the division unit 32 through the filter. The first filter unit 34 can also be described as extracting a desired frequency or cutting a desired frequency. The first filter unit 34 is equipped with one or more SAW filters, corresponding to the number of frequency divisions of the received radio wave. The number corresponding to the number of frequency divisions of the received radio wave can also be said to be the number corresponding to the number of MIMO stages.

[0027] SAW stands for Surface Acoustic Wave, which is an elastic surface wave. The SAW filter 342 has low loss and a steep cutoff characteristic. The SAW filter 342 can also be described as a type of bandpass filter (BPF). Although a detailed explanation is omitted here, other bandpass filters with low loss and a steep cutoff characteristic may be used instead of the SAW filter.

[0028] Multiple SAW filters provided in the first filter section 34 each allow a predetermined frequency band to pass through and extract a single modulated wave. In the following description, the SAW filters provided in the first filter section 34 may be referred to as the first SAW filter. In the first filter section 34, the electrical signals generated based on the radio waves received by the receiving antenna section 31 can also be passed through the multiple first SAW filters, allowing frequencies of a first bandwidth to pass through and extracting multiple single modulated waves.

[0029] The first variable control unit 35 varies the frequency of the first bandwidth, which is the frequency band of the electrical signal that the first filter unit 34 allows to pass through. Specific methods for varying the frequency band will be described later with reference to Figures 3 and 4, etc.

[0030] The second filter section 36 allows a desired frequency to pass through by passing the electrical signal that has passed through the first filter section 34 through the filter. The second filter section 36 can also be described as extracting a desired frequency or cutting a desired frequency. Here, the frequency band that the first filter section 34 passes through and the frequency band that the second filter section 36 passes through are different from each other. For example, by making the center frequency of the frequency band that the first filter section 34 passes through and the center frequency of the frequency band that the second filter section 36 passes through different, one filter may cut the higher frequency signal and the other filter may cut the lower frequency signal, resulting in a filter that passes through a narrow frequency band.

[0031] In the following description, the multiple SAW filters provided in the second filter section 36 may be referred to as the second SAW filters. The multiple second SAW filters are each connected in series with the multiple first SAW filters. The second SAW filters, like the first SAW filters, allow a predetermined frequency band to pass through. It can also be said that the predetermined frequency band that the first SAW filters allow to pass through is different from that of the first SAW filters. In the second filter section 36, by passing the signals through the second SAW filters connected in series with each of the first SAW filters, it is possible to pass frequencies with a second bandwidth different from the first bandwidth and extract multiple single modulated waves.

[0032] The second variable control unit 37 varies the frequency of the second bandwidth, which is the frequency band of the electrical signal that the second filter unit 36 ​​passes through. The specific method for varying the frequency band will be described later with reference to Figures 3 and 4, etc.

[0033] The transmitting antenna unit 38 transmits the electrical signal converted to a spatial multiplexing scheme. For example, if the MIMO has four stages, the transmitting antenna unit 38 has four antennas and transmits four spatially multiplexed radio waves. The figure illustrates an example where the transmitting antenna unit 38 has four antennas, but the number of antennas in the transmitting antenna unit 38 is not limited to this example. The transmitting antenna unit 38 may have, for example, a number of antennas corresponding to the number of MIMO stages.

[0034] The control unit 39 controls the frequency band of the signal that the first filter unit 34 passes through and the frequency band of the signal that the second filter unit 36 ​​passes through by transmitting control signals to the first variable control unit 35 and the second variable control unit 37. If the first filter unit 34 and the second filter unit 36 ​​each have multiple filters, the first variable control unit 35 and the second variable control unit 37 may control each filter so that it passes signals of different frequency bands. The control unit 39 also controls the number of MIMO stages by transmitting control signals to the MIMO stage control unit 33. Controlling the number of MIMO stages can also be rephrased as controlling the ON / OFF state of each filter.

[0035] Figure 3 is a second diagram schematically illustrating the functions of the repeater according to this embodiment. Referring to this figure, the process by which the repeater 30 extracts a single modulation from a signal divided into n parts by frequency multiplexing will be explained. For the sake of simplicity, the figure shows one of the multiple filters provided by the first filter unit 34 and the second filter unit 36. One of the multiple filters provided by the first filter unit 34 is referred to as the first filter unit 34a, and one of the multiple filters provided by the second filter unit 36 ​​is referred to as the second filter unit 36a. The multiple filters provided by the first filter unit 34 and the second filter unit 36 ​​(for example, the first filter units 34a to 34d and the second filter units 36a to 36d) may all have the configuration shown in the figure.

[0036] The first filter section 34 includes a resonant circuit 341, a SAW filter 342, and a resonant circuit 343. The resonant circuit 341, the SAW filter 342, and the resonant circuit 343 are connected in series with each other, with the resonant circuit 341 at the forefront, the SAW filter 342 after it, and the resonant circuit 343 further down the sequence. The first filter section 34 can also be configured to include resonant circuits before and after multiple SAW filters.

[0037] The resonant circuit 341 changes the frequency of the signal input to the first filter section 34.

[0038] SAW filter 342 is the first SAW filter described with reference to Figure 2.

[0039] The resonant circuit 343 changes the frequency of the signal output from the first filter section 34. The resonant circuit 343 can also restore the frequency that has been changed by the resonant circuit 341 to its original value. The resonant circuits 341 and 343 control the center frequency of the frequencies that are passed through. The first variable control unit 35 changes the bandwidth of the frequencies that the first filter section 34 passes through by controlling the resonant circuits 341 and 343 provided in the first filter section 34.

[0040] The second filter section 36 includes a resonant circuit 361, a SAW filter 362, and a resonant circuit 363. The resonant circuit 361, the SAW filter 362, and the resonant circuit 363 are connected in series with each other, with the resonant circuit 361 at the forefront, the SAW filter 362 after it, and the resonant circuit 363 further down the sequence. The second filter section 36 can also be configured to include resonant circuits before and after multiple SAW filters.

[0041] The resonant circuit 361 changes the frequency of the signal input to the second filter section 36.

[0042] SAW filter 362 is the second SAW filter, as explained with reference to Figure 2.

[0043] The resonant circuit 363 changes the frequency of the signal output from the second filter section 36. The resonant circuit 363 can also restore the frequency that has been changed by the resonant circuit 361 to its original value. The resonant circuits 361 and 363 control the center frequency of the frequencies that are passed through. The second variable control unit 37 changes the bandwidth of the frequencies that the second filter section 36 passes through by controlling the resonant circuits 361 and 363 provided in the second filter section 36.

[0044] The MIMO stage control unit 33 controls the number of radio waves transmitted by spatial multiplexing by disabling the operation of one of the multiple SAW filters provided in the first filter unit 34 and disabling the operation of one of the multiple SAW filters provided in the second filter unit 36. In the illustrated example, a configuration for one stage is shown, but the MIMO stage control unit 33 enables the filters according to the number of stages to be transmitted by MIMO and disables the rest.

[0045] Figure 4 is a diagram illustrating the control of the frequency band by the repeater according to this embodiment. The horizontal axis of the figure represents frequency [Hz (Hertz)], and the vertical axis represents gain [dB (decibels)]. In other words, the waveforms shown schematically represent the change in gain for each frequency. Waveform W1 shows the frequency characteristics of the electrical signal after passing through the first filter section 34. Waveform W2 shows the frequency characteristics of the electrical signal after passing through the second filter section 36.

[0046] Figure 4(A) shows an example of generating a broadband modulated wave by filtering the frequency characteristics of an input electrical signal. Frequency f11 is the center frequency of the frequency band passed through by the first filter section 34. Frequency f12 is the center frequency of the frequency band passed through by the second filter section 36. Frequency f11 is controlled by the first variable control section 35, and frequency f12 is controlled by the second variable control section 37. In the example shown in Figure 4(A), since frequencies f11 and f12 are relatively close to each other, there is a relatively large overlap in the frequency ranges of the electrical signals passed through the first filter section 34 and the second filter section 36, making it possible to generate a broadband modulated wave.

[0047] On the other hand, Figure 4(B) shows an example of generating narrowband modulation. Frequency f21 is the center frequency of the frequency band passed through by the first filter section 34. Frequency f22 is the center frequency of the frequency band passed through by the second filter section 36. Frequency f21 is controlled by the first variable control section 35, and frequency f22 is controlled by the second variable control section 37. In the example shown in Figure 4(B), since frequencies f21 and f22 are relatively far apart, there is relatively little overlap in the frequency domains of the electrical signals passed through the first filter section 34 and the second filter section 36, and a narrowband modulated wave can be generated.

[0048] As shown in Figures 4(A) and 4(B), according to this embodiment, the frequency band of the generated single modulated wave can be arbitrarily set by varying the center frequency of the frequency band passed through by the first filter unit 34 and the center frequency of the frequency band passed through by the second filter unit 36.

[0049] [Processing flow] The following describes the flow of a series of processes according to this embodiment with reference to Figures 5 to 7. According to this embodiment, the change in the wireless environment may be detected by the terminal device 10, the base station 20, or the repeater 30. Figures 5 to 7 differ in that each configuration detects the change in the wireless environment.

[0050] Figure 5 is a flowchart showing an example of a series of processes when the terminal device according to this embodiment detects changes in the wireless environment. First, an example of when the terminal device 10 detects changes in the wireless environment will be explained with reference to the figure. Of the processes shown in the figure, steps S115 to S117 are performed via a relay control line, which is different from the normal communication line, and is provided between the base station 20 and the repeater 30. Processes other than steps S115 to S117 are performed via the normal communication line.

[0051] (Step S111) First, the terminal device 10 detects a change in the wireless environment. Specifically, the change in the wireless environment is detected as a change in the communication rate. The change in the communication rate includes both deterioration and improvement.

[0052] (Step S112) When the terminal device 10 detects a change in the wireless environment, it notifies the repeater 30. When the repeater 30 receives the notification from the terminal device 10, it amplifies and relays it to the base station 20. In other words, the repeater 30 notifies the base station 20 that it has detected a change in the wireless environment.

[0053] (Step S113) When the base station 20 receives notification that it has detected a change in the wireless environment, it performs Rank Adaptation processing and communication bandwidth optimization processing. Rank Adaptation processing involves reducing the number of MIMO stages to improve quality where the reception level is low and the channel correlation is high, and increasing the number of MIMO stages to achieve high-speed transmission where the reception level is high and the channel correlation is low. Communication bandwidth optimization processing involves changing the frequency band that is passed through, as explained with reference to Figure 4.

[0054] (Step S114) If the base station 20 changes at least one of the following: the MIMO stage count (rank) or the passband, it notifies the repeater 30 of the changes. This notification includes the setting value for at least one of the MIMO stage count (rank) or the passband.

[0055] (Step S115) When the repeater 30 receives a notification from the base station 20 regarding a change in either the MIMO stage number (rank) or the passband, it makes the setting change based on the setting value included in the notification. Specifically, the setting for the MIMO stage number (rank) is made by the MIMO stage number control unit 33 controlling the enable / disable of the filter. The setting for the communication bandwidth is made by the first variable control unit 35 and the second variable control unit 37 changing the frequency of the first bandwidth and the frequency of the second bandwidth.

[0056] (Step S116) Once the repeater 30 has completed the configuration, it sends a notification to the base station 20 that the configuration has been completed (configuration completion notification).

[0057] (Step S117) When the base station 20 receives the configuration completion notification, it checks whether the configuration has been applied.

[0058] (Step S118) The base station 20 sends a notification regarding the changes via the repeater 30. The notification includes a setting value for at least one of the MIMO stage (rank) or passband.

[0059] (Step S119) The repeater 30 amplifies the notification from the base station 20 and relays it to the terminal device 10. That is, the repeater 30 notifies the terminal device 10 of the setting value for at least one of the MIMO stage number (rank) or passband.

[0060] (Step S120) When the terminal device 10 receives a notification from the base station 20 via the repeater 30 regarding a change in at least one of the following: a change in the MIMO stage (rank) or a change in the passband, it makes the setting change based on the setting value included in the notification.

[0061] (Steps S121 to S123) In the processes described above, the MIMO stage (rank) has been changed or the passband has been changed, so the terminal device 10, base station 20, and repeater 30 transmit and receive data with the new settings. If the terminal device 10 detects a change in the wireless environment again, the above series of processes will be performed again to change the MIMO stage (rank) or the passband.

[0062] Figure 6 is a flowchart showing an example of a series of processes when the repeater according to this embodiment detects changes in the wireless environment. Next, an example of when the repeater 30 detects changes in the wireless environment will be described with reference to the same figure. Of the processes shown in the figure, steps S311 to S316 are performed via a relay control line, which is different from the normal communication line, and is provided between the base station 20 and the repeater 30. Processes other than steps S311 to S316 are performed via the normal communication line.

[0063] (Step S311) First, the repeater 30 detects a change in the wireless environment. Specifically, the change in the wireless environment is detected as a change in the communication rate. The change in the communication rate includes both deterioration and improvement. When the repeater 30 detects a change in the wireless environment, it notifies the base station 20.

[0064] (Step S312) When the base station 20 receives notification that it has detected a change in the wireless environment, it performs Rank Adaptation processing and communication bandwidth optimization processing.

[0065] (Step S313) If the base station 20 changes at least one of the following: the MIMO stage count (rank) or the passband, it notifies the repeater 30 of the changes. This notification includes the setting value for at least one of the MIMO stage count (rank) or the passband.

[0066] (Step S314) When the repeater 30 receives a notification from the base station 20 regarding a change in either the MIMO stage number (rank) or the passband, it makes the setting change based on the setting value included in the notification. Specifically, the setting for the MIMO stage number (rank) is made by the MIMO stage number control unit 33 controlling the enable / disable of the filter. The setting for the communication bandwidth is made by the first variable control unit 35 and the second variable control unit 37 changing the frequency of the first bandwidth and the frequency of the second bandwidth.

[0067] (Step S315) Once the repeater 30 has completed the configuration, it sends a notification to the base station 20 that the configuration has been completed (configuration completion notification).

[0068] (Step S316) When the base station 20 receives the configuration completion notification, it checks whether the configuration has been applied.

[0069] (Step S317) The base station 20 sends a notification regarding the changes via the repeater 30. The notification includes a setting value for at least one of the MIMO stage (rank) or passband.

[0070] (Step S318) The repeater 30 amplifies the notification from the base station 20 and relays it to the terminal device 10. That is, the repeater 30 notifies the terminal device 10 of the setting value for at least one of the MIMO stage number (rank) or passband.

[0071] (Step S319) When the terminal device 10 receives a notification from the base station 20 via the repeater 30 regarding a change in at least one of the following: a change in the MIMO stage (rank) or a change in the passband, it makes the setting change based on the setting value included in the notification.

[0072] (Steps S320 to S322) In the processes described above, the MIMO stage (rank) has been changed or the passband has been changed, so the terminal device 10, base station 20, and repeater 30 transmit and receive data with the new settings. If the terminal device 10 detects a change in the wireless environment again, the above series of processes will be performed again to change the MIMO stage (rank) or the passband.

[0073] Figure 7 is a flowchart showing an example of a series of processing steps when a base station according to this embodiment detects changes in the wireless environment. Next, an example of when the base station 20 detects changes in the wireless environment will be explained with reference to the same figure. Of the processes shown in the figure, steps S513 to S516 are performed via a relay control line, which is different from the normal communication line, and is provided between the base station 20 and the repeater 30. Processes other than steps S513 to S516 are performed via the normal communication line.

[0074] (Step S511) First, the base station 20 detects a change in the wireless environment. Specifically, the change in the wireless environment is detected as a change in the communication rate. The change in the communication rate includes both deterioration and improvement.

[0075] (Step S512) When the base station 20 detects a change in the wireless environment, it performs Rank Adaptation processing and communication bandwidth optimization processing.

[0076] (Step S513) If the base station 20 changes at least one of the following: the MIMO stage count (rank) or the passband, it notifies the repeater 30 of the changes. This notification includes the setting value for at least one of the MIMO stage count (rank) or the passband.

[0077] (Step S514) When the repeater 30 receives a notification from the base station 20 regarding a change in either the MIMO stage number (rank) or the passband, it makes the setting change based on the setting value included in the notification. Specifically, the setting for the MIMO stage number (rank) is made by the MIMO stage number control unit 33 controlling the enable / disable of the filter. The setting for the communication bandwidth is made by the first variable control unit 35 and the second variable control unit 37 changing the frequency of the first bandwidth and the frequency of the second bandwidth.

[0078] (Step S515) Once the repeater 30 has completed the configuration, it sends a notification to the base station 20 that the configuration has been completed (configuration completion notification).

[0079] (Step S516) When the base station 20 receives the configuration completion notification, it checks whether the configuration has been applied.

[0080] (Step S517) The base station 20 sends a notification regarding the changes via the repeater 30. The notification includes a setting value for at least one of the MIMO stage (rank) or passband.

[0081] (Step S518) The repeater 30 amplifies the notification from the base station 20 and relays it to the terminal device 10. That is, the repeater 30 notifies the terminal device 10 of the setting value for at least one of the MIMO stage number (rank) or passband.

[0082] (Step S519) When the terminal device 10 receives a notification from the base station 20 via the repeater 30 regarding a change in either the MIMO stage number (rank) or the passband, it makes the setting change based on the setting value included in the notification.

[0083] (Steps S520 to S522) In the processes described above, the MIMO stage (rank) has been changed or the passband has been changed, so the terminal device 10, base station 20, and repeater 30 transmit and receive data with the new settings. If the terminal device 10 detects a change in the wireless environment again, the above series of processes will be performed again to change the MIMO stage (rank) or the passband.

[0084] [Internal structure] Figure 8 is a block diagram showing an example of the internal configuration of a repeater according to this embodiment. At least some of the functions of the repeater 30 can be realized using a computer as shown in the figure. The computer consists of a central processing unit (processor) 901, RAM 902, input / output ports 903, input / output devices 904 and 905, etc., and a bus 906. The computer itself can be realized using existing technology. The central processing unit 901 executes instructions contained in a program read from RAM 902, etc. The central processing unit 901 writes data to RAM 902, reads data from RAM 902, and performs arithmetic and logical operations according to each instruction. RAM 902 stores data and programs. Each element contained in RAM 902 has an address and can be accessed using that address. RAM stands for "Random Access Memory". Input / output ports 903 are ports for the central processing unit 901 to exchange data with external input / output devices, etc. Input / output devices 904 and 905 are input / output devices. Input / output devices 904 and 905 exchange data with the central processing unit 901 via input / output port 903. Bus 906 is a common communication channel used within the computer. For example, the central processing unit 901 reads and writes data to RAM 902 via bus 906. Also, for example, the central processing unit 901 accesses input / output ports via bus 906. Furthermore, all or part of the functional units of the repeater 30 may be implemented using hardware such as ASICs, PLDs, or FPGAs. Furthermore, all or part of the functional units may be implemented by a combination of software and hardware.

[0085] Furthermore, at least a portion of the internal configuration of the terminal device 10 and the base station 20 may also adopt the configuration shown in Figure 8.

[0086] [Summary of Embodiments] According to the embodiment described above, the repeater 30 converts the radio waves transmitted and received between the base station 20 and the terminal device from frequency multiplexing to spatial multiplexing and performs amplification relay. The repeater 30 includes a first filter unit 34, which allows the electrical signals generated based on the received radio waves to pass through a plurality of first SAW filters, which are provided according to the number of frequency divisions of the received radio waves, thereby allowing frequencies of a first bandwidth to pass through and extracting a plurality of single modulated waves. Furthermore, the repeater 30 includes a second filter unit 36, which allows the plurality of single modulated waves that have passed through the first filter unit 34 to pass through a second SAW filter connected in series with each of the plurality of first SAW filters, thereby allowing frequencies of a second bandwidth different from the first bandwidth to pass through. By adopting such a configuration, the repeater 30 can convert from frequency multiplexing to spatial multiplexing and perform amplification relay without digital processing. In other words, according to this embodiment, wireless signals can be relayed with low latency.

[0087] This embodiment differs from conventional technologies that perform regeneration relay (IAB relay) through digital processing by demodulation / remodulation. Such conventional technologies involve AD / DA conversion and digital filtering, which increases the number of taps. An increase in the number of taps means a significant increase in group delay time. Furthermore, if one attempts to perform FDM / SDM conversion within the CP length compliant with the 5G standard using AD / DA conversion and digital filtering, there are currently no semiconductor devices that can achieve and accommodate the processing time required.

[0088] Furthermore, with conventional technologies, while processing power increases due to the use of high-speed and high-performance AD / DA converters, the current consumption of the semiconductor also increases accordingly. This embodiment, however, does not use AD / DA converters, thus achieving the effect of suppressing current consumption.

[0089] Furthermore, while it is possible to switch between BPFs with different bandwidths, this embodiment employs an approach that passes the signal through two SAW filters, as described above. A method that switches between BPFs with different bandwidths would likely increase the circuit size, including switching circuits and control circuits. This embodiment offers the advantage of reducing the overall circuit size.

[0090] Furthermore, a method combining an LPF and an HPF is also conceivable, but this embodiment employs an approach that passes the signal through two SAW filters, as described above. When using an LPF and an HPF, the number of components is large and a large mounting space is required. In addition, when using an LPF and an HPF, insertion loss increases as the number of filter stages increases, which is a disadvantage. According to this embodiment, since the number of components is small, the advantage of not requiring a large mounting space is obtained. Furthermore, since there is no disadvantage of increased insertion loss when the number of filter stages increases, the advantage of suppressing current consumption is also obtained.

[0091] Furthermore, according to the embodiment described above, the repeater 30 includes a first variable control unit 35 to vary the frequency of the first bandwidth that the first filter unit 34 allows to pass through. In addition, the repeater 30 includes a second variable control unit 37 to vary the frequency of the second bandwidth that the second filter unit 36 ​​allows to pass through. By adopting such a configuration, the modulation bandwidth can be varied according to the communication conditions.

[0092] Furthermore, according to the embodiment described above, the first filter unit 34 is equipped with resonant circuits before and after a plurality of first SAW filters, and the second filter unit 36 ​​is equipped with resonant circuits before and after a plurality of second SAW filters. In addition, the first variable control unit 35 varies the frequency of the first bandwidth by controlling the resonant circuits of the first filter unit 34, and the second variable control unit 37 varies the frequency of the second bandwidth by controlling the resonant circuits of the second filter unit 36. By adopting such a configuration, the repeater 30 can easily vary the modulation bandwidth according to the communication conditions.

[0093] Furthermore, according to the embodiment described above, the repeater 30 further includes a MIMO stage control unit 33. The MIMO stage control unit 33 disables the operation of any of the multiple first SAW filters provided in the first filter unit 34, and disables the operation of any of the multiple second SAW filters provided in the second filter unit 36. By performing this control, the MIMO stage control unit 33 controls the number of radio waves transmitted by spatial multiplexing. Therefore, the repeater 30 can vary the number of MIMO stages according to the communication conditions.

[0094] Furthermore, the above-described embodiment, for example by "relaying wireless signals with low latency," makes it possible to contribute to Goal 9 of the United Nations-led Sustainable Development Goals (SDGs), "build resilient infrastructure, promote sustainable industrialization and foster innovation."

[0095] Although embodiments of the present invention have been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments, and design modifications and the like are also included within the scope of the gist of the present invention.

[0096] Alternatively, computer programs for realizing the functions of each of the above-mentioned devices may be recorded on a computer-readable recording medium, and the programs recorded on this recording medium may be loaded into a computer system and executed. Note that the term "computer system" here may include hardware such as an operating system and peripheral devices. Furthermore, "computer-readable recording media" refers to writable non-volatile memory such as flexible disks, magneto-optical disks, ROMs, and flash memory, portable media such as DVDs (Digital Versatile Discs), and storage devices such as hard disks built into computer systems.

[0097] Furthermore, "computer-readable recording media" also includes volatile memory (e.g., DRAM (Dynamic Random Access Memory)) within a computer system that acts as a server or client when a program is transmitted via a network such as the Internet or a communication line such as a telephone line, which retains the program for a certain period of time. In addition, the above program may be transmitted from the computer system that stores the program in a storage device, etc., to another computer system via a transmission medium or by transmission waves within the transmission medium. Here, the "transmission medium" for transmitting the program refers to a medium that has the function of transmitting information, such as a network such as the Internet or a communication line such as a telephone line. Furthermore, the above program may be for the purpose of realizing a part of the above-mentioned functions. Moreover, it may be a so-called differential file (differential program) that can realize the above-mentioned functions in combination with a program already recorded in the computer system. [Explanation of Symbols]

[0098] 1... Wireless system, 10... Terminal device, 20... Base station, 30... Repeater, 31... Receiving antenna unit, 32... Splitter unit, 33... MIMO stage control unit, 34... First filter unit, 35... First variable control unit, 36... Second filter unit, 37... Second variable control unit, 38... Transmitting antenna unit, 39... Control unit

Claims

1. A repeater that converts radio waves transmitted and received between a base station and a terminal device from frequency division multiplexing (FDM) to space division multiplexing (SDM), and performs amplification and relaying, A first filter unit extracts multiple single modulated waves by passing an electrical signal generated based on the received radio waves through a first SAW (Surface Acoustic Wave) filter, which is provided in multiple quantities according to the frequency division number of the received radio waves, thereby passing through frequencies of a first bandwidth. A second filter unit allows multiple single modulated waves that have passed through the first filter unit to pass through a second SAW filter connected in series with each of the multiple first SAW filters, thereby allowing frequencies of a second bandwidth different from the first bandwidth to pass through. A repeater equipped with the following features.

2. A first variable control unit for varying the frequency of the first bandwidth, A second variable control unit for varying the frequency of the second bandwidth, The repeater according to claim 1, further comprising the following:

3. The first filter section includes resonant circuits in the preceding and succeeding stages of a plurality of the first SAW filters, respectively. The second filter section includes resonant circuits in the preceding and succeeding stages of a plurality of the second SAW filters, respectively. The first variable control unit varies the frequency of the first bandwidth by controlling the resonant circuit provided in the first filter unit. The second variable control unit varies the frequency of the second bandwidth by controlling the resonant circuit provided in the second filter unit. The repeater according to claim 2.

4. The system further includes a MIMO (Multiple-Input Multiple-Output) stage control unit that controls the number of radio waves transmitted by spatial multiplexing by disabling the operation of any of the multiple first SAW filters provided in the first filter unit and disabling the operation of any of the multiple second SAW filters provided in the second filter unit. A repeater according to any one of claims 1 to 3.

5. A control method for a repeater that converts radio waves transmitted and received between a base station and a terminal device from frequency division multiplexing (FDM) to space division multiplexing (SDM) and performs amplification relay, A first filtering step involves passing an electrical signal generated based on the received radio waves through a first SAW filter, which is provided in multiple quantities according to the frequency division ratio of the received radio waves, thereby passing through frequencies of a first bandwidth and extracting multiple single modulated waves. A second filtering step is performed in which multiple single modulated waves that have passed through the first filtering step pass through a second SAW filter connected in series with each of the multiple first SAW filters, thereby allowing frequencies of a second bandwidth different from the first bandwidth to pass through. A control method for a repeater having [a certain feature].

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