Delay profile generation device, delay profile generation system, and delay profile generation method

Abstract

A delay profile generation device according to one embodiment comprises: a receiving antenna that receives and outputs a signal; a combining unit that adds the signal output by the receiving antenna to another signal and outputs the result; a transmitting antenna that transmits the input signal; a first cable that transmits, over a predetermined length, the signal output by the combining unit while amplifying the signal at a predetermined amplification factor; a second cable that is provided with a variable attenuator and transmits the signal attenuated by the variable attenuator at a predetermined attenuation factor; and a branching unit that branches the signal transmitted by the first cable and outputs the branched signals to the transmitting antenna and the second cable, respectively. The second cable transmits the signal input from the branching unit to the combining unit while attenuating the signal at a predetermined attenuation factor. The combining unit, first cable, branching unit, and second cable are housed in a housing so as to ensure isolation from the receiving antenna and the transmitting antenna.

Description

Delay Profile Generation Device, Delay Profile Generation System, and Delay Profile Generation Method

[0001] The present invention relates to a delay profile generation device, a delay profile generation system, and a delay profile generation method.

[0002] In order to apply a wireless communication system to high-reliability applications, there is an increasing need to reproduce the wireless environment in the assumed usage environment and conduct reliability tests on wireless characteristics.

[0003] For example, in Citation 1, a fading simulator used for reliability tests of wireless characteristics is disclosed. Also, by connecting one of the opposing wireless systems (a wireless base station) to the fading simulator, generating signals in a multi-path environment with different delays in the fading simulator, transmitting the signals from a transmitting antenna, and receiving them by the other wireless device (terminal), a method for testing wireless characteristics is known (see, for example, Non-Patent Document 1).

[0004] Also, a wireless space reproduction technology that reproduces an arbitrary propagation environment by controlling radio waves using RIS (Reconfigurable Intelligent Surfaces) based on intelligent space formation technology is known (see, for example, Non-Patent Document 2).

[0005] ”Anritsu Product Introduction MF6900A Fading Simulator”, [online], Anritsu Website, [searched on November 1, 2024], Internet <URL: https: / / dl.cdn-anritsu.com / ja-jp / test-measurement / files / Product-Introductions / Product-Introduction / MF6900A_JL1300.pdf>Taniguchi Ryotaro, et al., ”Evaluation of wireless space reproduction technology in indoor environment”, IEICE Society Conference 2023 B-1-104, September 2023.

[0006] However, conventionally, generating delay components in a wireless environment required signal processing to generate the delay components, necessitating high-speed digital signal processing as well as broadband analog-to-digital or digital-to-analog signal conversion. Furthermore, while conventional multipath environment generation using reflection devices could reproduce the reflection direction, it was not possible to reproduce the delay profile.

[0007] The present invention has been made in view of the above-mentioned problems, and aims to provide a delay profile generation device, a delay profile generation system, and a delay profile generation method that enable the reproduction of a stable delay profile in a wireless environment with a simple configuration.

[0008] A delay profile generating device according to one embodiment of the present invention comprises a receiving antenna that receives and outputs a signal, a combining unit that adds the signal output by the receiving antenna with another signal and outputs the result, a transmitting antenna that transmits an input signal, a first cable that transmits the signal output by the combining unit over a predetermined length while amplifying it at a predetermined amplification factor, a second cable equipped with a variable attenuator that transmits the signal while attenuating it at a predetermined attenuation factor by the variable attenuator, and a branching unit that branches the signal transmitted by the first cable and outputs it to the transmitting antenna and the second cable, respectively, wherein the second cable transmits the signal input from the branching unit to the combining unit while attenuating it at a predetermined attenuation factor, and the combining unit, the first cable, the branching unit, and the second cable are housed in a housing such that isolation is ensured from the receiving antenna and the transmitting antenna.

[0009] Furthermore, a delay profile generation system according to one embodiment of the present invention comprises a plurality of delay profile generation devices, each of which includes a receiving antenna port to which a receiving antenna that receives and outputs a signal can be connected, a combining unit that adds the signal received and output by the receiving antenna connected to the receiving antenna port with other signals and outputs the sum, a transmitting antenna port to which a transmitting antenna that transmits an input signal can be connected, a first cable that transmits the signal output by the combining unit over a predetermined length while amplifying it at a predetermined amplification factor, and a second cable equipped with a variable attenuator that transmits the signal at a predetermined attenuation factor by the variable attenuator. The delay profile generation device has a branching section that splits the signal transmitted by the first cable and outputs it to the transmitting antenna port and the second cable, respectively, the second cable transmits the signal input from the branching section to the combining section while attenuating it at a predetermined attenuation rate, the combining section, the first cable, the branching section, and the second cable are housed in a housing to ensure isolation from the receiving antenna and the transmitting antenna, and any of the delay profile generation devices are cascaded so that its own transmitting antenna port is connected to the receiving antenna port of the other delay profile generation device.

[0010] Furthermore, a delay profile generation method according to one embodiment of the present invention is characterized in that a combining unit that adds a signal output by a receiving antenna that receives and outputs a signal with another signal and outputs the result, a first cable that transmits the signal output by the combining unit over a predetermined length while amplifying it at a predetermined amplification factor, a second cable equipped with a variable attenuator that transmits the signal at a predetermined attenuation factor by the variable attenuator, and a branching unit that branches the signal transmitted by the first cable and outputs to a transmitting antenna and the second cable, respectively, is housed in a housing so as to ensure isolation from the receiving antenna and the transmitting antenna, the receiving antenna receives radio waves, the second cable transmits the signal input from the branching unit to the combining unit, along with the signal transmitted by the combining unit via the first cable, from the transmitting antenna to the receiving antenna, and the isolation between the transmitting antenna and the receiving antenna is changed.

[0011] According to the present invention, a stable delay profile in a wireless environment can be reproduced with a simple configuration.

[0012] This figure shows an example configuration of a delay profile generation device according to one embodiment. This graph illustrates a delay profile generated (reproduced) by the delay profile generation device. This figure shows an example configuration when adjusting the configuration of the delay profile generation device. This figure shows a modified example of the delay profile generation device. This figure shows an example configuration of a delay profile generation system according to one embodiment. This graph illustrates a delay profile generated (reproduced) by the delay profile generation system.

[0013] The following describes a delay profile generation device 1 according to one embodiment, using drawings. Figure 1 is a diagram showing an example of the configuration of the delay profile generation device 1 according to one embodiment. As shown in Figure 1, the delay profile generation device 1 includes a receiving antenna 2, a transmitting antenna 3, a combining unit 4, a first cable 5, a second cable 6, a branching unit 7, and a housing 8.

[0014] The receiving antenna 2 is connected to a receiving antenna port 20 provided on the housing 8, thereby receiving signals and outputting them to the combining unit 4.

[0015] The combining unit 4 adds the signal output by the receiving antenna 2 with other signals and outputs the result to the first cable 5. For example, the combining unit 4 is a 4-port hybrid circuit with one output port terminated, and adds the signal output by the receiving antenna 2 with the signal transmitted by the second cable 6 and outputs the result to the first cable 5.

[0016] The first cable 5 includes, for example, a variable amplifier 50 that amplifies the signal at a predetermined amplification factor, and transmits the signal output by the combining unit 4 with a predetermined amplification factor over a length that causes a predetermined delay. For example, the first cable 5 may be configured such that the variable amplifier 50 is directly connected to the RF cable, and further, the RF cable is directly connected to the variable amplifier 50. Alternatively, the first cable 5 may be an amplifier coaxial cable. The variable amplifier 50 is set to be changeable so that the amplification factor is, for example, 1 or more.

[0017] The second cable 6 is equipped with a variable attenuator 60 that attenuates the signal at a predetermined attenuation rate, and transmits the signal at a predetermined attenuation rate by the variable attenuator 60. For example, the second cable 6 may be configured such that the variable attenuator 60 is directly connected to the RF cable, and further, the RF cable is directly connected to the variable attenuator 60. For example, the second cable 6 transmits the signal input from the branching section 7 to the combining section 4 while attenuating it at a predetermined attenuation rate. The variable attenuator 60 is set so that the attenuation rate can be changed.

[0018] The branching section 7 splits the signal transmitted by the first cable 5 and outputs it to the transmitting antenna 3 and the second cable 6, respectively. For example, the branching section 7 is a 4-port hybrid circuit with one input port terminated, and outputs the signal transmitted by the first cable 5 to the transmitting antenna 3 and the second cable 6, respectively.

[0019] The transmitting antenna 3 is connected to the transmitting antenna port 30 provided on the housing 8, thereby transmitting the signal input from the branching unit 7.

[0020] The housing 8 houses the combining section 4, the first cable 5, the branching section 7, and the second cable 6, and the combining section 4, the first cable 5, the branching section 7, and the second cable 6 are configured to ensure isolation from the receiving antenna 2 and the transmitting antenna 3.

[0021] Furthermore, the delay profile generation device 1 has a loop formed inside the housing 8 such that the signals transmitted in the order of the combining unit 4, the first cable 5, the branching unit 7, and the second cable 6 return to the combining unit 4.

[0022] Furthermore, the delay profile generation device 1 transmits the signal from the radio waves received by the receiving antenna 2 inside the housing 8, delays it using the first cable 5, and transmits it through the transmitting antenna 3, where it is received again by the receiving antenna 2. For example, the delay profile generation device 1 causes the transmitting antenna 3 to transmit to the receiving antenna 2 the signal transmitted by the combining unit 4 via the first cable 5 (including the signal received by the receiving antenna 2) along with the signal that the combining unit 4 transmits to the receiving antenna 2 via the second cable 6 from the branching unit 7.

[0023] In other words, a loop is formed that goes from receiving antenna 2 → inside the housing 8 → transmitting antenna 3 → receiving antenna 2.

[0024] Furthermore, the delay profile generation device 1 sets the amount of attenuation per unit of delay time from when the signal output by the combining unit 4 is transmitted until it returns to the combining unit 4 to a value obtained by subtracting the amplification by the variable amplifier 50 from the sum of the attenuation due to isolation between the receiving antenna 2 and the transmitting antenna 3, the attenuation due to the first cable 5, the attenuation due to the second cable 6, and the attenuation due to the variable attenuator 60.

[0025] For example, Δτ is calculated from the propagation speed v of radio waves within the first cable 5 (and the second cable 6) and the cable length of the first cable 5 (and the second cable 6).

[0026] Δτ is the delay time when the RF signal is passed through a loop that returns from receiving antenna 2 → inside the housing 8 → transmitting antenna 3 → receiving antenna 2.

[0027] Then, if P is the amount of attenuation per Δτ in the attenuation model of the propagation environment to be reproduced, the amount of attenuation α by the variable attenuator 60, etc., is set to satisfy the following equation (1).

[0028] α = P + G - β ... (1)

[0029] Note that α [dB] is the sum of the isolation between the receiving antenna 2 and the transmitting antenna 3, and the attenuation of the path through the variable attenuator 60. Also, G [dB] is the gain of the variable amplifier 50, β [dB] is the attenuation in one loop, and L is the cable length in one loop.

[0030] When attenuation is performed by the variable attenuator 60, G and α are set to satisfy the following equation (2).

[0031] G-α = -P+β...(2)

[0032] In other words, the delay profile generation device 1 is configured such that the receiving antenna 2 and transmitting antenna 3 satisfy the following equation (3), where P [dB] is the attenuation per Δτ of the delay profile to be reproduced.

[0033] P = α+β-G...(3)

[0034] Figure 2 is a graph illustrating a delay profile generated (reproduced) by the delay profile generation device 1. In Figure 2, the vertical axis represents the signal strength transmitted through the loop formed by the receiving antenna 2, the inside of the housing 8, and the transmitting antenna 3. The horizontal axis represents the delay time from when the receiving antenna 2 received the signal.

[0035] Furthermore, the delay profile generation device 1 is capable of changing the isolation between the receiving antenna 2 and the transmitting antenna 3, and the isolation between the receiving antenna 2 and the transmitting antenna 3 may be adjusted while the delay profile is being generated.

[0036] α [dB] is set, measured, and adjusted during initial setup (initial setup mode) by the following methods or combinations thereof.

[0037] ・A method of changing the directivity direction of at least one of the receiving antenna 2 and the transmitting antenna 3 ・A method of changing the distance between the receiving antenna 2 and the transmitting antenna 3 ・A method of inserting a shielding object between the receiving antenna 2 and the transmitting antenna 3 ・A method of changing the attenuation amount by the variable attenuator 60

[0038] Thus, the delay profile generation device 1 can reproduce a stable exponential model delay profile in a wireless environment with a simple configuration without using analog-to-digital conversion.

[0039] FIG. 3 is a diagram showing a configuration example (delay profile generation device 1a) when adjusting the configuration of the delay profile generation device 1. Hereinafter, the same reference numerals are given to the configurations substantially the same as those of the delay profile generation device 1 shown in FIG. 1.

[0040] The delay profile generation device 1a includes a receiving antenna 2, a transmitting antenna 3, a first cable 5, a first switching unit 90, a measuring unit 91, a second switching unit 92, a standard signal generation unit 93, and a housing 8.

[0041] The delay profile generation device 1a is used in an initial setting mode and a normal mode.

[0042] In the initial setting mode, the first switching unit 90 connects the receiving antenna 2 to the measuring unit 91, and the second switching unit 92 connects the transmitting antenna 3 and the standard signal generation unit 93. Also, in the normal mode, the first switching unit 90 connects the receiving antenna 2 to the first cable 5.

[0043] △τ is the delay time when an RF signal is passed through a loop that returns like receiving antenna 2 → inside the housing 8 → transmitting antenna 3 → receiving antenna 2.

[0044] Here, when the attenuation amount per △τ in the delay profile to be reproduced is P, the receiving antenna 2 and the transmitting antenna 3 are set so that the isolation α satisfies the following equation (4).

[0045] P = α + β - G ··· (4)

[0046] Note that G [dB] is the gain of the variable amplifier 50, β [dB] is the attenuation in one loop, and L is the cable length of one loop.

[0047] α [dB] is set, measured, and adjusted by the following methods or combinations of methods in the initial setting mode described later.

[0048] - Method of changing the directivity of at least one of the receiving antenna 2 and the transmitting antenna 3 - Method of changing the distance between the receiving antenna 2 and the transmitting antenna 3 - Method of inserting a shielding object between the receiving antenna 2 and the transmitting antenna 3

[0049] FIG. 4 is a diagram showing a modified example (delay profile generation device 1b) of the delay profile generation device 1. The delay profile generation device 1b includes a receiving antenna 2, a transmitting antenna 3, a combining unit 4a, a first cable 5a, a second cable 6a, a branching unit 7a, an E / O conversion unit (E / O) 94, an O / E (O / E) conversion unit 95, and a housing 8.

[0050] The E / O conversion unit 94 performs electro-optical conversion on the signal received by the receiving antenna 2 and outputs it to the combining unit 4a. The O / E conversion unit 95 performs opto-electrical conversion on the signal output by the branching unit 7 and outputs it to the transmitting antenna 3.

[0051] The combining unit 4a adds the signal electro-optically converted by the E / O conversion unit 94 and another signal, and outputs it to the first cable 5a. For example, the combining unit 4a is a 4-port hybrid circuit with one output port terminated, adds the signal electro-optically converted by the E / O conversion unit 94 and the signal transmitted by the second cable 6a, and outputs it to the first cable 5a.

[0052] The first cable 5a includes, for example, a variable amplifier 50a that amplifies a signal at a predetermined amplification rate, and transmits the signal output by the combining unit 4a at a length that causes a predetermined delay while amplifying it at the predetermined amplification rate. For example, the first cable 5 is an optical fiber cable. Note that the variable amplifier 50a is set to be changeable so that the amplification rate is, for example, 1 or more.

[0053] The second cable 6a is equipped with a variable attenuator 60a that attenuates the signal at a predetermined attenuation rate, and transmits the signal at a predetermined attenuation rate by the variable attenuator 60a. For example, the second cable 6a is an optical fiber cable. The variable attenuator 60a is set to allow the attenuation rate to be changed.

[0054] The branching section 7a splits the signal transmitted by the first cable 5a and outputs it to the O / E conversion section 95 and the second cable 6a, respectively. For example, the branching section 7a is a 4-port hybrid circuit with one input port terminated, and outputs the signal transmitted by the first cable 5a to the O / E conversion section 95 and the second cable 6a, respectively.

[0055] The transmitting antenna 3 is connected to the transmitting antenna port 30 provided on the housing 8, thereby transmitting the signal input from the O / E conversion unit 95.

[0056] The housing 8 houses the combining section 4a, the first cable 5a, the branching section 7a, the second cable 6a, the E / O conversion section 94, and the O / E conversion section 95, and the first cable 5a, the branching section 7a, the second cable 6a, the E / O conversion section 94, and the O / E conversion section 95 are configured to ensure isolation from the receiving antenna 2 and the transmitting antenna 3.

[0057] In other words, the delay profile generation device 1b can handle optical signals when generating a delay profile, similar to the delay profile generation device 1 shown in Figure 1, and can reduce attenuation in the cable.

[0058] Furthermore, in the delay profile generation device 1b, the adjustment of α and G is possible in the same way as in the delay profile generation device 1. Note that if the attenuation in the loop is sufficiently small, the delay profile generation device 1b does not need to be equipped with a variable amplifier 50a (G may be 1).

[0059] Figure 5 shows an example of the configuration of a delay profile generation system 100 according to one embodiment. As illustrated in Figure 5, the delay profile generation system 100 is configured by cascading multiple (two or more) delay profile generation devices 1c.

[0060] Specifically, the delay profile generating device 1c has its own transmitting antenna port 30 connected to the receiving antenna port 20 of another delay profile generating device 1c by a cable 96.

[0061] Each delay profile generation device 1c has the same configuration as the housing 8 of the delay profile generation device 1 shown in Figure 1, housed within the housing 8, and has substantially the same functions as the delay profile generation device 1.

[0062] Furthermore, the delay profile generation device 1b is configured such that each delay profile generation device 1c houses its circuitry within the housing 8, preventing interference between the delay profile generation devices 1c. Therefore, the delay profile generation device 1b can generate an exponential delay profile model that is closer to the actual environment.

[0063] The delay profile generation system 100 generates a cluster of delayed waves that decay exponentially in the time axis direction by setting the time interval for generating delayed waves to Δτ' (< Δτ). Each cluster of delayed waves consists of delayed waves that decay exponentially in the time axis direction.

[0064] Figure 6 is a graph illustrating a delay profile generated (reproduced) by the delay profile generation system 100. As shown in Figure 6, the delay profile generation system 100 generates a cluster of delayed waves. The dashed arrows in the cluster of delayed waves shown in Figure 6 represent delayed waves generated by the cascading connection of delay profile generation devices 1c.

[0065] Furthermore, the delay profile generation system 100 can also form multiple clusters by cascading multiple delay profile generation devices 1c.

[0066] Furthermore, the delay profile generation devices 1a and 1b described above may also be connected in a cascade configuration.

[0067] 1, 1a, 1b, 1c... Delay profile generation device, 2... Receiving antenna, 3... Transmitting antenna, 4, 4a... Combining unit, 5, 5a... First cable, 6, 6a... Second cable, 7, 7a... Branching unit, 8... Housing, 20... Receiving antenna port, 30... Transmitting antenna port, 50... Variable amplifier, 60... Variable attenuator, 90... First switching unit, 91... Measurement unit, 92... Second switching unit, 93... Standard signal generation unit, 94... E / O conversion unit, 95... O / E conversion unit, 96... Cable, 100... Delay profile generation system

Claims

1. A delay profile generation device comprising: a receiving antenna that receives and outputs a signal; a combining unit that adds the signal output by the receiving antenna with another signal and outputs the result; a transmitting antenna that transmits an input signal; a first cable that transmits the signal output by the combining unit over a predetermined length while amplifying it at a predetermined amplification factor; a second cable equipped with a variable attenuator that transmits the signal while attenuating it at a predetermined attenuation factor by the variable attenuator; and a branching unit that branches the signal transmitted by the first cable and outputs it to the transmitting antenna and the second cable, respectively, wherein the second cable transmits the signal input from the branching unit to the combining unit while attenuating it at a predetermined attenuation factor, and the combining unit, the first cable, the branching unit, and the second cable are housed in a housing such that isolation is ensured from the receiving antenna and the transmitting antenna.

2. The delay profile generation device according to claim 1, characterized in that the combining unit is a four-port hybrid circuit with one output port terminated, and the branching unit is a four-port hybrid circuit with one input port terminated.

3. The delay profile generating device according to claim 1 or 2, characterized in that the amount of attenuation per unit of delay time from when the signal output by the combining unit is transmitted until it returns to the combining unit is the sum of attenuation due to isolation between the receiving antenna and the transmitting antenna, attenuation due to the first cable, attenuation due to the second cable, and attenuation due to the variable attenuator, minus the amplification due to the amplification factor.

4. The delay profile generation device according to claim 1 or 2, characterized in that the isolation between the receiving antenna and the transmitting antenna is variable.

5. The delay profile generating device according to claim 1 or 2, characterized in that at least the first cable is an optical fiber cable.

6. The delay profile generation device according to claim 1 or 2, characterized in that the first cable is equipped with a variable amplifier to amplify the signal output by the combining unit at a predetermined amplification factor.

7. The system comprises multiple delay profile generation devices, each of which includes: a receiving antenna port to which a receiving antenna that receives and outputs a signal can be connected; a combining unit that adds the signal received and output by the receiving antenna connected to the receiving antenna port with another signal and outputs the sum; a transmitting antenna port to which a transmitting antenna that transmits an input signal can be connected; a first cable that transmits the signal output by the combining unit over a predetermined length while amplifying it at a predetermined amplification factor; a second cable equipped with a variable attenuator that transmits the signal at a predetermined attenuation factor by the variable attenuator; and a branching unit that branches the signal transmitted by the first cable and outputs it to the transmitting antenna port and the second cable, respectively, the second cable transmits the signal input from the branching unit to the combining unit while attenuating it at a predetermined attenuation factor, the combining unit, the first cable, the branching unit, and the second cable are housed in a housing to ensure isolation from the receiving antenna and the transmitting antenna, and any of the delay profile generation devices are A delay profile generation system characterized in that its own transmitting antenna port is cascaded to the receiving antenna port of another delay profile generation device.

8. A delay profile generation method characterized by housing in a housing such that isolation is ensured between the receiving antenna and the transmitting antenna, the receiving

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