JP3013277B2 - Propagation path simulator for one-frequency alternate communication system for mobile communication - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a propagation path simulating apparatus for simulating a change in an actual propagation path in a one-frequency alternating communication system for mobile communication in mobile communication.

[0002]

2. Description of the Related Art FIG. 4 is a block diagram of a conventional channel simulation device. The propagation path simulator includes a distributor 401, a synthesizer 4
07, 90-degree phase shifter 402, mixers 403, 404, Gaussian random number generation circuits 405, 406, amplifiers 408, 41
0, a delay time generation circuit 409. Input terminal 412
Is input to the Rayleigh fading generation section 411 and distributed by the distributor 401 into two systems of high-frequency signals. The distributed high-frequency signal of one system is phase-shifted by a 90-degree phase shifter 402. The high frequency signals of the two systems are then multiplied by the mixers 403 and 404 with the signals generated by the Gaussian noise generating circuits 405 and 406, and are modulated by the Gaussian noise. The high-frequency signal modulated by the Gaussian noise is combined by the combiner 407 to become a signal subjected to Rayleigh fading. Next, the high-frequency signal that has undergone Rayleigh fading is amplified by a level adjustment amplifier 408 and then input to a delay time generation circuit 409. The high-frequency signal is delayed by a prescribed time by the delay time generation circuit 409, and becomes a signal that has undergone the same fluctuation in level, phase, and delay time as propagated through the multiplex wave propagation path generated in land mobile communication. Finally, the signal is amplified by the level adjustment amplifier 410 and output from the output terminal 413.

[0003] By using this conventional propagation path simulating apparatus, it was possible to measure various transmission characteristics in one direction (for example, from a base station to a mobile station) in a propagation environment of land mobile communication by laboratory experiments. .

[0004]

In the mobile communication using the one-frequency alternating communication system, since the carrier frequency is the same, the downlink propagation path from the base station to the mobile station and the uplink propagation path from the mobile station to the base station. Has reciprocity. That is, the fading received by the uplink signal and the downlink signal is the same.

However, in an apparatus for simulating one propagation path as in the prior art, since an active element is used as a circuit component, there is no reciprocity when viewed from an input terminal and an output terminal. For this reason, there has been a problem that it is not possible to evaluate the transmission quality of the mobile communication using the one-frequency alternating communication system in a laboratory experiment or the like.

An object of the present invention is to provide a bidirectional propagation path simulator.

[0007]

A feature of the present invention to achieve the above object is a propagation path simulating circuit for transmitting signals in only one direction in a propagation path simulating apparatus used in a one-frequency alternating communication system for mobile communication. And a means for switching the connection between the input and output terminals of the propagation path simulating circuit in accordance with the envelope detection signal of the input signal in one transmission direction.

[0008]

The input terminal is connected to the transmitter of the base station and the output terminal is connected to the receiver of the mobile station during the period when the conventional propagation path simulating apparatus communicates from the base station to the mobile station in the one-frequency alternating communication system. The input terminal is connected to the transmitter of the mobile station, and the output terminal is connected to the receiver of the base station during the period of communication from the mobile station to the base station. By making a circuit to switch the switch as described above, one propagation path is time-divisionally up-path,
By using it as a downstream propagation path,
To realize a propagation path simulator capable of testing in both directions in the frequency alternating communication system.

The present invention will be described below with reference to the drawings.

FIG. 1 is a configuration diagram of a propagation path simulating apparatus related to the present invention. This propagation path simulator includes a PIN switch, a distributor, a combiner, a conventional propagation path simulator, and a continuously variable attenuator capable of providing an attenuation amount proportional to an external control voltage.

In the one-frequency alternating communication system for mobile communication, which is a field of application of the present invention, as shown in FIG. 2, an uplink signal and a downlink signal are alternately transmitted and received using the same frequency as a carrier frequency while dividing time. . The timing of transmission and reception
The base station creates the timing, and the mobile station synchronizes dependently on the base station.

The input / output terminals 101 and 102 are connected to antenna terminals of a base station. The input / output terminal 103 is connected to an antenna terminal of the mobile station. The present embodiment is a system for evaluating transmission quality when receiving diversity and transmitting diversity are performed in a base station. Each of the input / output terminals 101, 102 and 103 has a PIN switch 10
4, 105 and 106 are connected. The PIN switch is connected to the combiners 107, 108 and 109 on the input side of the conventional channel simulator by the control signals input to the external control input terminals 114, 115 and 116. Output side distributor 11
0, 111, and 112 are alternately connected. During the period during which the base station transmits the downlink signal to the mobile station, the external control input terminal 1
PIN switch 104 (105) at 15 (116)
Is a synthesizer 107 (10) on the input side of the conventional channel simulation device.
In 8), a control signal is input to the PIN switch 106 so as to be connected to the synthesizer 112 on the output side of the conventional channel simulator, and the base station antenna terminal and the base station input / output terminal 101 are input.
(102), PIN switch 104 (105), combiner 107 (108), conventional channel simulator 113, continuous variable attenuator 117 (118), distributor 110 (11)
1) A downstream propagation path is formed with the synthesizer 112, the PIN switch 106, the mobile station input / output terminal 103, and the mobile station antenna terminal. PIN switches 104, 105, 106
Are a base station input / output terminal 101 (102), a PIN switch 104 (105), a distributor 107 (108), a distributor 109, and a PIN switch because a distributor and a combiner are used in addition to the original propagation path. Unnecessary waves wrapping around the mobile station input / output terminal 103 through a propagation path formed with 106, or base station input / output terminals 101 (102), PIN switches 104 (105), distributors 107 (108), conventional propagation paths Simulator 113, continuous variable attenuator 117 (11
8), distributor 110 (111), PIN switch 104
Through the base station input / output terminal 101 (10
This is necessary to block unnecessary waves returning to 2). The signal passing through the downstream propagation path formed as described above undergoes instantaneous fluctuations in amplitude and phase due to fading peculiar to land mobile communication in a conventional propagation path simulator. Next, the continuous variable attenuator receives attenuation of the power of the amount of attenuation that changes according to the control voltage applied to the continuous variable attenuator. The control voltage applied to the continuously variable attenuator varies when the central value fluctuates in a narrow section that follows a lognormal distribution, which is a problem in mobile communications, or when a large radio wave shield such as a truck passes near the base station or mobile station. By making it proportional to the attenuation corresponding to the attenuation of the radio wave due to shadowing that occurs in such a situation, a situation close to the actual propagation path can be realized in a laboratory experiment.

Next, during the period of transmitting the uplink signal from the mobile station to the base station, the PIN switches 104 and 105 are respectively connected to the external control input terminals 114, 115 and 116 by the output side distributor 110 of the conventional channel simulator. , 111 and the PIN switch 106 are connected to the distributor 10 on the input side of the conventional channel simulator.
9 is connected to the mobile station antenna terminal, mobile station input / output terminal 103, PIN switch 1
06, distributor 109, combiners 107 and 108, conventional channel simulator 113, continuous variable attenuators 117 and 118,
Distributors 110 and 111, PIN switches 104 and 10
5, an uplink propagation path is formed with the base station input / output terminals 101 and 102 and the base station antenna terminal. The PIN switch is
Also, since a distributor and a combiner are used in addition to the original propagation path, the mobile station input / output terminal 103, the PIN switch 10
6. Unwanted waves circulating to base station input / output terminals 101 and 102 through a propagation path formed by distributor 109, combiners 107 and 108, and PIN switches 104 and 105, or mobile station input / output terminal 103 and PIN switch 106 , Distributor 109, combiners 107 and 108, conventional channel simulator 113, continuous variable attenuators 117 and 118, distributor 1
10, 111, the combiner 112, and the PIN switch 106, which are necessary to block unnecessary waves returning to the mobile station input / output terminal 103 again.

As described above, by using the PIN switch, the distributor, and the combiner, the transmission quality of the one-frequency alternating communication system can be evaluated by a laboratory experiment using the conventional non-reciprocal propagation path simulator. Become like

[0015]

FIG. 3 is a block diagram showing an embodiment of the present invention. The propagation path simulation device according to the present embodiment includes a circulator 30
1, 302, 303, distributor 109, synthesizers 107, 1
08, 112, PIN switches 304, 305, coaxial envelope detector 306, conventional channel simulator 113, and continuous variable attenuators 117, 118.

The coaxial envelope detector 306 detects an upstream signal from a mobile station. During a period when the base station is transmitting the downlink signal to the mobile station, the detector output becomes 0, the PIN switch is connected to the b side, and the base station antenna terminal 101 (10
2), circulator 301 (302), synthesizer 107
(108), conventional channel simulator 113, continuous variable attenuator 117 (118), PIN switch 304 (30)
5), a downlink propagation path is formed with the combiner 112, the circulator 303, and the mobile station antenna terminal 103, and a downlink signal is transmitted from the base station to the mobile station. Base station antenna terminal 101 (102), circulator 301 (302),
Unwanted waves entering the combiners 107 (108), the distributor 109, and the circulator 303 are cut off due to the amount of reverse attenuation of the circulator 303, and the mobile station antenna terminal 103
Does not reach.

Next, during a period in which the mobile station transmits an uplink signal to the base station, the mobile station transmits the uplink signal, and the coaxial envelope detector 306 detects the uplink signal. 305 is connected to the a side, and the mobile station antenna terminal 103, circulator 303, distributor 109, combiners 107 and 108, conventional channel simulator 113, continuous variable attenuators 117 and 118, PIN switches 304 and 305, circulator 301, 302,
An uplink propagation path is formed with the base station antenna terminals 101 and 102, and an uplink signal is transmitted from the mobile station to the base station.

Since the upstream and downstream propagation paths realized by the present invention are subjected to amplitude and phase fluctuations by one conventional propagation path simulator and continuous variable attenuator for both the upstream signal and the downstream signal, one frequency in mobile communication is used. It has the same properties as the propagation path of the alternate communication system. Therefore, by using the present invention, it is possible to simulate a propagation path of the one-frequency alternating communication system in mobile communication in a laboratory.

[0019]

As described above, since the propagation path simulating apparatus of the present invention simulates reciprocity, the transmission quality when a technique specific to the one-frequency alternate communication system such as transmission diversity is applied is tested in a laboratory. Can be evaluated.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a propagation path simulation device related to the present invention.

FIG. 2 is a frame configuration diagram of a one-frequency alternating communication system for mobile communication.

FIG. 3 is a configuration diagram of one embodiment of a propagation path simulation device of the present invention.

FIG. 4 is a configuration diagram of a conventional propagation path simulation device.

[Explanation of symbols]

101, 102 Base station side input / output terminal 103 Mobile station side input / output terminal 104, 105, 106, 304, 305 PIN switch 107, 108, 112, 407 Synthesizer 109, 110, 111, 401 Divider 113 Propagation path simulator 117, 118 Continuous variable attenuator 301, 302, 303 Circulator 402 90-degree phase shifter 403, 404 Mixer 405, 406 Gaussian noise generator 408, 410 Amplifier 409 Delay time generation circuit

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04B ⁷ /24-7/26 113 H04B 17/00-17/02 H04Q 7/06-7/38

Claims (1)

(57) [Claims] An apparatus for simulating a propagation path used in a one-frequency alternating communication system for mobile communication, comprising: a propagation path simulating circuit for transmitting a signal in only one direction; and an envelope detection signal of an input signal in one transmission direction. Means for switching connection of input / output terminals of the propagation path simulation circuit.