JP3376269B2 - Communication performance evaluation device - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to ASK, FSK,
The present invention relates to a communication performance evaluation device that evaluates communication performance and tests frequency sharing in a communication system that performs wireless communication and telecommunication by digital modulation such as PSK and SS.

[0002]

2. Description of the Related Art Conventionally, a communication system for performing wireless communication and telecommunication has a communication performance satisfying a user's request in its communication quality in an environment where interference waves and unnecessary radio waves emitted from various systems are mixed. Is required.

Therefore, a noise pace test apparatus has been developed as a means for solving the noise problem in the usage environment.

In the current test equipment, white Gaussian noise is used as a noise source, and Gaussian noise is applied to a communication signal of a communication system, so that the
The communication performance is evaluated by the bit error rate (BER) with respect to energy-to-noise density (Eb / N0) and carrier-to-noise power ratio (C / N).

For example, a delayed interference wave in wireless communication is
The transmitted signal is caused by reflection, refraction and scattering by objects such as the ground, buildings, walls or floors. The phase of the reflected or scattered delayed wave is randomly distributed according to the characteristics such as the shape and the dielectric constant of the reflector. That is, when the reflector is larger than one wavelength, the phase of the reflected wave is from 0 degree to 36 degrees.
It is evenly distributed between 0 degrees.

According to the central limit theorem, if the number of interference waves is large and all the interference waves have almost the same amplitude, it is known that the sum has an in-phase component and a quadrature component that follow a normal Gaussian distribution. There is.

For this reason, white Gaussian noise is often used for communication performance evaluation of radio communication systems as an interference wave in which both the phase and the amplitude fluctuate randomly.

Also, in telecommunications, thermal noise is a typical noise, and therefore communication performance evaluation of a communication system using white Gaussian noise is also commonly used.

[0009]

First, in a wireless communication system, for example, code division multiplexing (Code Division M
In an actual asynchronous communication system such as an ultimate access (CDMA) communication system, the number of simultaneously received interference waves and the amplitudes of the interference waves are different, so that a specific interference wave often affects the communication quality.

Further, in a complicated electromagnetic environment in which unnecessary radio waves from various systems are mixed, the generation mechanism of unnecessary radio waves is different, and types such as noise having periodicity are also various.

Further, there is a demand for effective use of limited frequency resources, and it is conceivable that a plurality of systems share the same frequency band.

At this time, since the communication quality varies depending on the modulation method and type of the interference wave, it is necessary to evaluate the interference characteristic between the wireless communication systems of different methods as one of the communication performances.

On the other hand, also in the telecommunication system, it is conceivable that the same cable is used to perform large-capacity communication at various frequencies.

Therefore, if it is possible to previously evaluate the mutual influence between the signals when different communication methods are simultaneously transmitted using the same cable by a simple test method, it is more economical to construct the communication cable. Can be done.

Even in such a case, an evaluation device for simultaneously transmitting communication signals of different communication systems and the like is required.

In view of the above problems, it is an object of the present invention to provide a communication performance evaluation apparatus capable of easily evaluating the influence of various communication signals and noises of different communication systems on a communication system to be evaluated.

[0017]

In order to achieve the above object, the present invention provides, in claim 1, amplitude modulation (ASK), frequency modulation (FSK), phase modulation (PSK), and spectrum spread modulation ( Amplitude modulation in a communication performance evaluation device that evaluates communication performance by a measure such as a bit error rate (BER) for a communication system that performs wireless communication and telecommunication by a communication signal generated using digital modulation such as SS). Proposes a communication performance evaluation device equipped with noise injection means for injecting, as noise into the communication signal, a single or a plurality of modulated signals modulated using digital modulation such as frequency modulation, phase modulation and spread spectrum modulation. .

According to the communication performance evaluation apparatus, a single or a plurality of modulated signals modulated by the noise injection means using digital modulation such as amplitude modulation, frequency modulation, phase modulation and spread spectrum modulation are evaluated. It is injected as noise to the communication signal of the communication system. As a result, it is possible to easily evaluate the influence of the same noise as various communication signals of different communication systems under the actual operating environment of the communication system on the communication signal of the communication system to be evaluated and to easily perform the frequency sharing test. be able to.

According to a second aspect of the present invention, in the communication performance evaluation apparatus according to the first aspect, the noise injection means changes the frequency band of the modulated signal and the modulation rate of the modulated signal. Then, a communication performance evaluation device including a modulation factor varying means and an intensity varying means for varying the intensity of the modulated signal is proposed.

According to the communication performance evaluation apparatus, since the frequency band, the modulation rate and the intensity of the modulation signal to be injected as noise into the communication signal can be set arbitrarily, noise generated from a specific electronic device is generated. Is possible,
It is possible to evaluate the influence of noise generated from a specific electronic device on the communication system to be evaluated.

A third aspect of the present invention proposes the communication performance evaluation apparatus according to the first aspect, further comprising Gaussian noise injection means for injecting white Gaussian noise into the communication signal.

According to the communication performance evaluation apparatus, various communication signals of different communication systems by the noise injection means and white Gaussian noise injection means can be injected simultaneously into the communication signal of the communication system to be evaluated. , It is possible to evaluate the communication performance of the communication system by creating a more practical operating environment.

According to a fourth aspect, in the communication performance evaluation apparatus according to the first aspect, the noise injection means generates noise based on intensity information and phase information of noise radiated from a specific electronic device that has been actually measured. There is proposed a communication performance evaluation device which has a noise generating unit for injecting the noise generated by the noise generating unit into the communication signal.

According to the communication performance evaluation apparatus, unnecessary noise radiated from a specific electronic device is generated based on actual measurement information and injected into the communication signal of the communication system to be evaluated, so that it is more practical. It is possible to create an operating environment and evaluate the communication performance of a communication system.

[0025] According to a fifth aspect, in the communication performance evaluation apparatus according to the first aspect, the noise injecting means is an M value F.
When performing SK modulation or M-ary PSK modulation, a communication performance evaluation device is proposed which changes the power density of the modulated signal by fixing the center frequency and the signal pass bandwidth and changing the value of M.

According to the communication performance evaluation apparatus, the M value FSK
When a modulated signal that has been modulated or M-valued PSK modulation is used as noise, the power density of noise can be easily changed arbitrarily by changing the value of M. Therefore, it is possible to easily create actual environmental noise and unnecessary noise. The performance of the communication system can be evaluated.

According to a sixth aspect of the present invention, in the communication performance evaluation apparatus according to the first aspect, the noise injecting means fixes a center frequency and a signal pass bandwidth and a spread code when performing spread spectrum modulation by direct spread. We propose a communication performance evaluation apparatus that changes the power density of the modulated signal by changing the spreading code length while keeping the operating frequency of the same.

According to the communication performance evaluation apparatus, when the modulated signal subjected to spread spectrum modulation by direct spread is used as noise, the power density of noise can be easily changed arbitrarily by changing the spread code length. It is possible to easily create actual environmental noise and unnecessary noise to evaluate the performance of the communication system.

According to a seventh aspect of the present invention, in the communication performance evaluation apparatus according to the first aspect, when the noise injection means performs spread spectrum modulation by frequency hopping,
We propose a communication performance evaluation device that changes the power density of the modulated signal by fixing the signal occupied bandwidth and changing the number of hops.

According to the communication performance evaluation apparatus, when the modulated signal subjected to spread spectrum modulation by frequency hopping is used as noise, the power density of noise can be easily changed arbitrarily by changing the number of hoppings.
It is possible to easily create actual environmental noise and unnecessary noise to evaluate the performance of the communication system.

[0031]

DETAILED DESCRIPTION OF THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. In the present embodiment, wireless devices that use the same or overlapping wireless frequencies are mixed, and ISM (Industrial Scienti
BER of SS modulation communication system which is particularly useful for frequency coexistence and communication performance evaluation in a frequency band such as c and Medical band, and is adopted for ISM band wireless LAN.
Communication performance and frequency coexistence using characteristics (coexistence of wireless devices)
A communication performance evaluation device that evaluates is described below.

FIG. 1 is a block diagram showing a communication performance evaluation apparatus for evaluating communication performance and frequency coexistence of a wireless communication system using SS modulation according to the first embodiment of the present invention. In the figure, 101, 108 and 116 data generators generate random digital data signals using mutually independent PN (Psuedo Noise) sequences.

102 is an intermediate frequency carrier generator, 103,
106 and 111 are mixers, 104, 107 and 112 are band pass filters, 105 and 109 are amplifiers, 113 is a variable amplifier, and 110 is a carrier generator for radio frequency (hereinafter referred to as RF).

Further, 117 is a memory for recording the bit string of the data signal output by the data generator 116, 114
Is a transmitter of the communication system to be measured, 115 is a directional coupler that combines the communication signal of the communication system to be measured and the interference noise output from the variable amplifier 113, and 118 is Gaussian noise that generates white Gaussian noise. Generator,
119 is a directional coupler that combines the Gaussian noise output from the Gaussian noise generator 118 and the output signal of the directional coupler 115, 120 is the receiver of the communication system to be measured, and 12
1 is a data receiving device that receives the data of the random bit string generated by the data generating device 116, and 122 is a memory that stores the bit string received by the data receiving device 121.

Here, noise injection means is constituted by the configuration from the data generator 101 to the variable amplifier 113, and the directional coupler 115, the Gaussian noise generator 118, and the directional coupler 119.

The data signal output from the data generator 101 is combined by the mixer 103 with the carrier of the intermediate frequency output from the carrier generator 102, and is input to the amplifier 105 via the bandpass filter 104 to obtain the signal strength. Is amplified.

The output signal of the amplifier 105 is combined with the data signal output from the data generator 108 by the mixer 106, and is then passed through the bandpass filter 107 to the amplifier 109.
Is input to and the signal strength is amplified.

The output signal of the amplifier 109 is combined with the RF carrier wave output from the carrier wave generator 110 by the mixer 111, and is then passed through the band pass filter 112 to the variable amplifier.
It is input to 113 and the signal strength is amplified. The RF signal output from the variable amplifier 113 is input to the directional coupler 115 via a coaxial cable or a waveguide.

On the other hand, the data signal output from the data generator 116 is input to the transmitter 114 of the communication system to be measured, and the transmitter 114 outputs an RF signal modulated based on the input data signal. . Here, the bit string of the data signal output from the data generator 116 is automatically stored in the memory 117.

Further, the RF signal output from the transmitter 114 is directional coupler 115 via a coaxial cable or a waveguide.
To the directional coupler via a coaxial cable or waveguide after being combined with the RF signal output from the amplifier 115.
The signal is input to 119, is multiplexed with the Gaussian noise generated by the Gaussian noise generator 118, and is input to the receiver 120 of the communication system to be measured.

The receiving device 120 can demodulate the communication signal transmitted from the transmitting device 104, demodulates the data signal from the received RF signal and outputs it to the data receiving device 121, and the data receiving device 121 inputs it. The data of the random bit string is received and stored in the memory 122.

Here, at least in the data generator 108, PN such as M series, Gold series and Baker series is used.
It is possible to select a sequence, and it is possible to arbitrarily change the code length and chip length (operating frequency) of one cycle. That is, it is possible to perform SS modulation with various spreading factors. However, as in the actual SS modulator, (time length per bit of random data generator 101) and {(time length per bit of random data generator 108) × (code length of one cycle )} Are set to be equal.

According to the above configuration, the memory 117 and the memory
The BER can be obtained by comparing the bit string of the received data with the pit string of the transmitted data stored in 122.

Further, although noise is added to the RF signal (communication signal) output from the transmitter 114 by the directional coupler 115, the center frequency and the bandwidth of the bandpass filter 112 are changed or the bandpass filter is changed. Filter 112
By using a bandpass filter having any desired center frequency and bandwidth, the noise frequency and bandwidth can be changed, and the noise intensity can be changed by the variable amplifier 113. This allows the specific noise environment to be set freely.

When the Gaussian noise generator 118 and the directional coupler 119 are connected, it is possible to test the influence of other radio signals on the Gaussian noise communication path. In other words, it is possible to test the communication performance in the actual communication path by adding the Gaussian noise and the simulated communication signal at the same time, and it is also possible to evaluate the interference characteristics with the actual communication device by selecting the type of noise. It will be possible.
In addition, it is possible to artificially evaluate unnecessary noise from electronic devices.

Furthermore, when the output of the directional coupler 115 is directly input to the receiver 120 without connecting the Gaussian noise generator 118 and the directional coupler 119, the data generator 10
1 to it is possible to test only the effect of the noise generated by the variable amplifier 113. That is, it is possible to evaluate the influence on the communication system under test by adding noise simulating the communication signal of SS modulation having various modulation rates, intensities, frequencies, and bands by the data generator 101 to the variable amplifier 113. Becomes

As described above, by using the device of the present embodiment, coexistence with other devices using the same frequency band as the communication system of interest and existence in the communication frequency band of the communication system of interest. It is possible to evaluate the communication performance of the influence on unwanted radio waves from other devices.
If the research is conducted before putting the communication system into practical use, the performance of the communication system will be realized. Therefore, it is possible not only to know in advance about operational problems after practical use, but also
This is effective in developing new communication methods and control methods.

Also in the frequency hopping communication system, the data generators 101 and 108 for noise generation are used.
A frequency synthesizer is used to change the hopping pattern, the time interval of hopping, and the combination of hopping numbers between systems, so that the coexistence of frequency hopping communication systems and the coexistence of direct spreading and frequency hopping communication systems Can also be evaluated, so that the same evaluation can be performed.

In addition, the noise added is ASK modulated wave, FS
By using various digital modulation waves such as K modulation wave, PSK modulation wave and QAM modulation wave alone or in combination, various frequency coexistence and communication performance can be evaluated.

Next, an embodiment of the data generators 101 and 108 for generating the above-mentioned noise will be described. FIG. 2 is a block diagram showing an example of the data generating devices 101 and 108 for generating noise. Here, an example of a device that generates a digitally modulated signal that is often used at present and is used as a noise source will be described.

In FIG. 2, 201 is a data generator for generating random digital data, and the generated data includes RZ (Return to Zero) and NRZ (Non Return to).
Zero), CMI (Code Mark Inversion), ANI (Alt
ernative Mark Inversion), Manchester, etc. data formats can be selected, the operating frequency can be changed, and it is created by PN code strings such as M series and Gold series.
The code can be selected.

Further, 202, 213 and 214 are mixers, and 203 and 215 are Sin capable of setting an arbitrary frequency and initial phase.
Wave generators, 204 and 208 are switches, 205 is a variable amplifier for making the amplitude of the Sin wave signal output from the Sin wave generator 203 correspond to the multi-level modulation of the data generator 201, and 206 and 217 are frequency Synthesizer, 207 is a phase converter, 209 and 218 are amplifiers for changing the signal strength, 210 and 219 are band pass filters whose center frequency and bandwidth can be changed, 211 and 220 are output terminals, 212
And 216 are PN code generators.

The output signal of the data generator 201 is the mixer 202.
Where it is mixed with the output signal of either the variable amplifier 205, the frequency synthesizer 206 or the phase converter 207.

Variable amplifier 205, frequency synthesizer 206
And the phase shifter 207 to the Si via the switch 204.
The Sin wave signal output from the n wave generator 203 is input.

The signal mixed by the mixer 202 is input to the amplifier 209 or the mixer 213 via the switch 208.

The amplifier 209 amplifies the signal input through the switch 208, and then uses this signal in the band pass filter 21.
Output to output terminal 211 via 0.

The mixer 213 mixes the signal input through the switch 208 and the output signal of the PN code generator 212 and outputs the mixed signal to the mixer 214.

The mixer 214 mixes the signal input from the mixer 213 and the output signal of the frequency synthesizer 217 and outputs the mixed signal to the amplifier 218. Where frequency synthesizer 217
The Sin wave signal output from the Sin wave generator 215 and the output signal of the PN code generator 216 are input to the.

The amplifier 218 amplifies the signal input from the mixer 214, and then outputs this signal to the output terminal 220 via the bandpass filter 219.

In addition, the data generator 201 is ASK, FS
When multi-value modulation such as K and PSK is performed, multi-value conversion of M values is performed, and when N signals are added as noise to a communication signal, N independent data are created from PN codes. . That is, it has N outputs that generate an independent data string of M values.

When a signal of M-ary ASK modulation is created by the data generator having the above structure, the variable amplifier 20
The reference numeral 5 distributes M-level amplitudes to the M-value output of the data generator 201. For example, in the case of 4-value ASK, Si
The amplitude of the n-wave generator 103 is set so that channel 1 has amplitude 0 and channels 2, 3, and 4 have amplitudes 0.33, 0.67, and 1, respectively.

When creating a signal of M-ary FSK modulation,
A frequency synthesizer 206 sets M frequencies for the multi-valued data converted into M values.

Further, in the case of creating an M-ary PSK modulated signal, the phase converter 207 allocates 360 ° / M phases to each of the M-ary multi-valued data.

ASK, FSK, created as described above
The center frequency of the PSK modulation signal is set by the Sin wave generator 203, and the variable amplifier 209 and the band pass filter are set.
At 210, the intensity and frequency bandwidth are set to arbitrary values, and the signal is output from the output terminal 211.

Further, generation of SS modulation signals of direct sequence modulation, frequency hopping modulation and hybrid modulation of these can be realized by switching the switch 208 to the mixer 213 side and performing secondary modulation.

That is, the PN code generator 212 can set an arbitrary PN code string, code length, and operating frequency, and the output signal of the PN code generator 212 creates a spread spectrum modulation signal by direct spread. It

Further, in the case of spread spectrum modulation by frequency hopping, the frequency synthesizer 217 is used without using the output signal of the PN code generator 212, and the PN code string output from the PN code generator 216 by the frequency synthesizer 217. According to the above, frequency hopping modulation is performed by hopping the frequency of the carrier wave of the Sin wave generator 215. Further, when performing frequency hopping modulation, the time interval for hopping can be changed by the frequency synthesizer 217.

By operating both the PN code generator 212 and the frequency synthesizer 217, direct modulation and frequency hopping hybrid modulation are also possible.

The signal secondarily modulated by the PN code generator 212 or the frequency synthesizer 217 is supplied to the variable amplifier 21.
8 and the band pass filter 219 set the intensity and frequency band to an arbitrary level, and output to the output terminal 220.

In this embodiment, M-value FSK modulation, M-value
In the case of the value PSK modulation, the center frequency and the signal pass bandwidth are fixed, and the value of M is changed to change the power density of the signal passing through the band pass filter. Can be added to the system.

In the case of spread spectrum modulation by direct spread, the center frequency and the signal pass bandwidth are fixed and P
By changing the spreading code length while keeping the operating frequency of the N code the same, the power density of the signal passing through the band pass filter can be changed and added as noise to the wireless communication system or the telecommunication system.

Furthermore, in the case of spread spectrum modulation by frequency hopping, the signal occupying bandwidth is fixed, and the bandpass is achieved by changing the number of hops or the bandwidth of the narrowband signal (the bandwidth of the primary-modulated signal). The power density of the signal passing through the filter can be changed and added to the wireless communication system or the telecommunication system as noise.

With the above configuration, it is possible to generate a digital modulation signal that is often used now. By using this as a noise source, it is possible to evaluate coexistence with various wireless or telecommunication systems with one system. You can

Further, the existing noise generator can only evaluate the communication performance in which the noise power density within a certain frequency band is constant and only the noise power is changed, but the communication performance evaluation apparatus of this embodiment Since the noise power density can be changed to an arbitrary value, the evaluation of the communication performance with respect to the actual environmental noise and unnecessary noise can be made closer to the reality.

Next, a second embodiment of the present invention will be described. FIG. 3 is a block diagram showing the communication performance evaluation apparatus of the second embodiment. Here, in order to simplify the description, the first embodiment described above is embodied, and a configuration for evaluating interference characteristics and frequency sharing between direct spread spectrum wireless communication systems having the same center frequency and wireless occupied frequency Here is an example:

In FIG. 3, 301 is a data generator and 30
2 is a memory for recording the bit string of the digital data output from the data generator 301, and 303 is a transmitter of the communication system to be evaluated and measured.
The data input from 1 is directly spread spectrum modulated and transmitted.

Reference numeral 303 denotes a signal generator which generates, as a noise signal, a direct spread spectrum signal having the same center frequency and radio occupied frequency as the transmission signal of the transmitter 302. Further, the signal generator 303 is, for example, the data generators 101 and 108 and the carrier wave generator 10 in the first embodiment described above.
2,110, mixers 103,106,111, bandpass filters 104,10
Including a 7,112 and an amplifier 105, a built-in band-pass filter that can change the frequency band and bandwidth arbitrarily, the frequency band and bandwidth of the output signal can be set arbitrarily, and the modulation rate of the output signal can also be set arbitrarily. is there.

A variable amplifier 305 changes the intensity of the signal input from the signal generator 304 and outputs it.

Power measuring devices 306 and 307 measure the power of the signals generated from the transmitting device 303 and the variable amplifier 305, respectively.

Reference numeral 308 denotes a directional coupler which multiplexes the signals output from the transmitting device 303 and the variable amplifier 305 to obtain a receiving device.
Output to 309.

Reference numeral 309 is a receiver of the communication system to be evaluated and measured, which can demodulate the communication signal transmitted from the transmitter 303.

Reference numeral 310 is a random bit string data receiving device, and 311 is a memory for recording the bit string received by the data receiving device 310.

Further, the data receiving device 310 has a memory 302.
It is possible to read the bit string recorded in the
The error rate is measured by comparing the transmission signal of 303 and the data demodulated by the receiving device 309, that is, the bit string recorded in the memory 311, and this result is output.

FIG. 4 shows the BER characteristics measured by the communication performance evaluation apparatus having the above structure. In FIG.
The horizontal axis represents S / N, which is the ratio of the power value of the communication signal measured by the power measuring device 306 to the power value of noise measured by the power measuring device 307. The vertical axis represents BER, which is the bit error rate of the bit string received by the data receiving device 310 with respect to the bit string output from the data generating device 301.

Further, FIG. 4 also shows the BER characteristics when Gaussian noise is added to the communication signal in order to compare the evaluation method according to this embodiment with the conventional evaluation method.

From the measurement results shown in FIG. 4, the BER characteristics of the communication system to be evaluated differ depending on the type of noise added, and when the communication performance was evaluated, all the interference waves were evaluated as Gaussian noise. If this is the case, it will be difficult to make an accurate estimate.

This also shows that the communication performance evaluation apparatus for a communication system of the present invention can realize more accurate communication performance evaluation.

Next, a third embodiment of the present invention will be described. FIG. 5 is a block diagram showing a communication performance evaluation apparatus according to the third embodiment of the present invention. Here, in order to simplify the description, the above-described first embodiment is embodied, and a configuration example in the case of evaluating interference characteristics and frequency sharing between direct spread spectrum wireless communication systems having the same center frequency and wireless occupied frequency Indicates.

In the figure, 401 is a data generator, and 402
Is a memory for recording the bit string of the digital data output from the data generator 401, and 403 is a transmitter of the communication system to be evaluated and measured, which directly spread spectrum modulates the digital data output from the data generator 401 and transmits it. To do.

A signal generator 404 generates a direct spread spectrum signal having the same center frequency and radio occupied frequency as the transmission signal of the transmitter 403 as a noise signal. Further, the signal generator 403 is, for example, the data generators 101 and 108 and the carrier wave generator 10 in the above-described first embodiment.
2,110, mixers 103,106,111, bandpass filters 104,10
Including a 7,112 and an amplifier 105, a built-in band-pass filter that can change the frequency band and bandwidth arbitrarily, the frequency band and bandwidth of the output signal can be set arbitrarily, and the modulation rate of the output signal can also be set arbitrarily. is there.

Reference numeral 405 is a variable amplifier for changing the intensity of the signal output from the signal generator 404, and 406 and 407.
Is a power measuring device, which is a transmitter 403 and a variable amplifier, respectively.
Measure the power of the signal generated by the 405.

Reference numeral 408 denotes a directional coupler, which multiplexes the signals output from the transmission device 403 and the variable amplifier 405 and outputs the multiplexed signals to the directional coupler 413.

409 is a Gaussian noise generator for generating white Gaussian noise, and 410 is a bandpass filter.
The band pass filter can be set to the same pass band as the output stage band pass filter incorporated in the signal generator 404 and the output stage band pass filter incorporated in the transmitter 403.

Reference numeral 411 is a variable amplifier which changes the output level of the Gaussian noise signal output from the Gaussian noise generator 409 and passed through the bandpass filter 410, and outputs it.

Reference numeral 412 is a power measuring device for measuring the power of the signal output from the variable amplifier 411.

413 is a directional coupler, which is a directional coupler 408.
And the output signal of the variable amplifier 411 are multiplexed and output to the receiving device 414.

A receiver 414 of the communication system to be evaluated and measured can demodulate the communication signal transmitted from the transmitter 403.

Reference numeral 415 is a data receiving device for a random bit string, and 416 is a memory for recording the bit string received by the data receiving device 415.

Further, the data receiving device 415 has a memory 402.
It is possible to read out the bit sequence recorded in, and to compare the bit sequence (data transmitted by the transmission device 403) with the data demodulated by the reception device 414, that is, the bit sequence recorded in the memory 416. The error rate (BER) is measured and this result is output.

In the communication performance evaluation device having the above-mentioned configuration, the RF signal (communication signal) transmitted from the transmitter 403 is used.
In contrast, the output signal of the signal generator 404, that is, the modulated wave noise simulating the other transmitter, and the Gaussian noise generator
Gaussian noise output from 409 is added, and the communication performance when this mixed signal is received can be evaluated.

As a result, when the interference noise can be regarded as Gaussian noise, that is, when the number of interference waves from the transmitters existing in the same communication area is large or the number of delayed interference waves is large, the noise of a specific communication signal is reduced. Communication performance can be evaluated.

FIG. 6 is a diagram showing the BER characteristics measured by the measurement system having the configuration shown in FIG. In the figure, the horizontal axis represents S / N, which is the ratio between the power value of the communication signal measured by the power measuring apparatus 406 and the power value of noise measured by the power measuring apparatus 407. The vertical axis represents BER, which is the bit error rate of the bit string received by the data receiving device 415 with respect to the bit string output from the data generating device 401.

Further, in the figure, the ratio (dB) between the measured power value output to the power measuring device 406 and the measured power value output to the power measuring device 412 is 3 dB, 5 dB, 10 dB,
And BER characteristics for S / N in the respective cases of 15 dB and 15 dB. That is, the power ratio between the transmission signal of the transmission device 403 and the Gaussian noise is 3 dB, 5 dB, 10 d.
It shows the BER characteristics with respect to the ratio of the communication signal to be measured and the interference noise in the cases of B and 15 dB.

As shown in the figure, in the third embodiment,
It is possible to accurately evaluate the interference characteristics with specific interference noise (interference noise output by the signal generator 404 in FIG. 5) under Gaussian noise and coexistence with a specific transmitter.

Similar to the method described above, by using communication signals of various communication systems in combination as interference noise for various communication systems, it is possible to perform more detailed evaluation of communication performance than before. In addition, it is possible to simultaneously evaluate the abstract communication performance based on Gaussian noise and the communication performance against specific interference noise.

Next explained is the fourth embodiment of the invention. FIG. 7 is a block diagram showing the communication performance evaluation apparatus of the fourth embodiment. Here, the data is AS as a communication signal.
A configuration example for evaluating interference characteristics and frequency sharing between wireless communication systems when digitally modulated signals such as K, FSK, PSK, QAM, GMSK, SS, and various multilevel modulations are used will be shown.

In FIG. 7, 501 is a data generator and 50 is a data generator.
2 is a memory for recording the bit string of the digital data output from the data generator 501, 503 is a transmitter of the communication system to be evaluated and measured, and the data generator 50
Input the digital data output from 1, and input ASK, FSK, PSK, QAM, GMS to this data.
The digital modulation such as K, SS or various multi-level modulation is applied and transmitted. The modulation by the transmission device 503 may be any of the above-mentioned modulation methods.

A signal generator 504 includes, for example, the data generators 101 and 108, the carrier wave generators 102 and 110, the mixers 103, 106 and 111, the band pass filters 104, 107 and 112, and the amplifier 105 in the first embodiment described above, and has an arbitrary frequency band and bandwidth. Built-in variable band pass filter,
The frequency band and bandwidth of the output signal can be set arbitrarily, and the modulation factor of the output signal can be set arbitrarily, and a digital modulation signal for evaluating the influence on the communication system is generated.

505 is a variable amplifier for changing the intensity of the output signal of the signal generator 504, 506 and 507 are power measuring devices for the signals output from the transmitting device 503 and the variable amplifier 505, and 508 is a transmitting device 503. Of the variable amplifier 505 and the output signal of the variable amplifier 505.

Further, 509 is a Gaussian noise generator for generating white Gaussian noise, 510 is a band pass filter, which can be set to the frequency band to be evaluated, and a Gaussian noise signal is input from the Gaussian noise generator 509. It is output as a Gaussian noise signal in a preset frequency band.

511 is a variable amplifier for changing the output level of the Gaussian noise signal output from the bandpass filter 510, 512 is a switch for switching the injection of Gaussian noise to the communication signal, and 513 is a power measuring device.
Measure the power of the Gaussian noise signal output through switch 512.

514 is a directional coupler, which is a directional coupler 508.
The mixed signal output from the switch and the Gaussian noise signal output via the switch 512 are mixed and output to the receiving device 515.

Reference numeral 512 denotes a receiver of the communication system to be evaluated and measured, which can demodulate the communication signal transmitted from the transmitter 503, and outputs the demodulated digital data to the data receiver 516.

Reference numeral 516 denotes a data receiving device, which records the bit string of the digital data input from the receiving device 515 in the memory 517, reads the bit string recorded in the memory 502, and reads this bit string (data transmitted by the transmitting device 403). ) Is compared with the data demodulated by the receiving device 515, that is, the bit string recorded in the memory 517, and the bit error rate (BER) is measured and this result is output.

According to the above configuration, various digital modulation signals can be directly injected as noise into the communication signal of the communication system to be measured, and the influence and performance thereof can be evaluated.

Next explained is the fifth embodiment of the invention. FIG. 8 is a block diagram showing a communication performance evaluation apparatus according to the fifth embodiment of the present invention. In the figure, 601 is a data generator, 602 is a memory for recording a bit string of digital data output from the data generator 601, 603 is a transmitter of the communication system to be evaluated and measured, and is output from the data generator 601. Input digital data,
For this data, ASK, FSK, PSK, QAM,
The digital modulation such as GMSK, SS or various multi-level modulation is applied and transmitted. The modulation by the transmission device 603 may be any of the above-mentioned modulation methods.

The transmission signal (communication signal) of the transmission device 603 is
The receiving device 60 of the communication system to be evaluated and measured through the coaxial cable, the waveguide, and the directional couplers 604 and 605.
Entered in 6.

The receiver 606 can demodulate the communication signal transmitted from the transmitter 603, and outputs the demodulated digital data to the data receiver 607.

The data receiving device 607 records the bit string of the digital data input from the receiving device 606 in the memory 608, reads the bit string recorded in the memory 602, and reads this bit string (data transmitted by the transmitting device 603). And the data demodulated by the receiver 606,
That is, the bit error rate (BER) is measured by comparing with the bit string recorded in the memory 608 and this result is output.

Further, 609 is a Gaussian noise generator for generating white Gaussian noise, and 610 is a band pass filter, which can be set to the frequency band to be evaluated, and a Gaussian noise signal is input from the Gaussian noise generator 609. It is output as a Gaussian noise signal in a preset frequency band.

Reference numeral 611 is a variable amplifier for changing the output level of the Gaussian noise signal output from the band pass filter 610, and 612 is a switch for switching the presence or absence of Gaussian noise injection into the communication signal, which is output via the switch 612. The Gaussian noise signal is injected into the communication signal by the directional coupler 605.

Further, each of 613-1 to 613-n is a signal generator, for example, the data generators 101 and 108, the carrier wave generators 102 and 110, and the mixer 10 in the above-described first embodiment.
3,106,111, bandpass filter 104,107,112, amplifier 10
Incorporating a band-pass filter that can arbitrarily change the frequency band and bandwidth, including 5, the output signal frequency band and bandwidth can be set arbitrarily, and the output signal modulation rate can also be set arbitrarily. Generate a digitally modulated signal to evaluate the effect on the system.

Each of 614-1 to 614-n is a signal generator 61.
A variable amplifier provided corresponding to each of 3-1 to 613-n changes the intensity of the output signal of the signal generators 613-1 to 613-n and outputs it. The signals output from the variable amplifiers 614-1 to 614-n are injected into the communication signal by the directional coupler 604.

Each of 615-1 to 615-n is a variable amplifier 614-
1 to 614-n power measurement device for signals output from the device, 616 denotes power measurement device for communication signals output from the transmission device 603, 61
Reference numeral 7 is a power measuring device for a Gaussian noise signal output via the switch 612.

According to the communication performance evaluation apparatus having the above-mentioned configuration, it is possible to directly inject a plurality of digital modulation signals as noise into the communication signal of the communication system to be measured, and to combine the injected noises. Since various settings can be made, it is possible to create an environment that is almost the same as the actual system operating environment and perform performance evaluation.

In each of the above-described embodiments, the performance evaluation of the wireless communication system has been described as an example, but it is needless to say that the same effect can be obtained in the wired communication system as well.

Further, in each of the above-described embodiments, noise and other communication signals are generated based on the random digital data generated by the data generator, but the present invention is not limited to this and, for example, no radio wave reflection occurs. Noise radiated from a specific electronic device measured in a free space such as a room, information recording the temporal variation of the strength and phase of the communication signal, or noise measured in a free space at the actual communication system operating place. Based on the information that records the temporal variation of the strength and phase of the communication signal, noise is generated for the communication signal of the communication system to be evaluated by using a signal generator that generates and outputs noise and other communication signals. The same effect can be obtained by injecting.

Furthermore, communication performance evaluation when these noises are injected may be performed by emulation by a computer.

[0129]

As described above, according to the communication performance evaluation apparatus of the first aspect of the present invention, communication signals of various communication systems can be easily used as interference noise for various communication systems. Therefore, including the coexistence with other devices that use the same frequency band as the communication system to be evaluated and the effect on unwanted radio waves from other devices existing in the communication frequency band of the communication system to be evaluated, etc. The communication performance can be easily evaluated.

Further, according to claim 2, in addition to the effect of claim 1, the frequency band, the modulation rate and the intensity of the modulation signal to be injected as noise into the communication signal of the communication system to be evaluated are arbitrarily set. Therefore, it is possible to generate the noise emitted from the specific electronic device, and it is possible to evaluate the influence of the noise emitted from the specific electronic device on the communication system to be evaluated.

According to a third aspect, in addition to the effect of the first aspect, various communication signals of different communication systems by the noise injection means and Gaussian noise injection means white.
Since Gaussian noise can be injected simultaneously into the communication signal of the communication system to be evaluated, it is possible to create a more practical operating environment and evaluate the communication performance of the communication system.

According to claim 4, in addition to the effect of claim 1, unnecessary noise radiated from a specific electronic device is generated on the basis of actual measurement information, and a communication signal of a communication system to be evaluated. Since it is injected into, it is possible to create a more practical operating environment and evaluate the communication performance of the communication system.

Further, according to claim 5, in addition to the effect of claim 1, by changing the value of M when the modulated signal subjected to M-value FSK modulation or M-value PSK modulation is used as noise. Since the power density of noise can be easily changed arbitrarily, it is possible to easily create actual environmental noise and unnecessary noise and evaluate the performance of the communication system.

According to the sixth aspect, in addition to the effect of the first aspect, when the modulated signal subjected to the spread spectrum modulation by the direct spread is used as the noise, the noise can be easily changed only by changing the spread code length. Since the power density of can be changed arbitrarily, it is possible to easily create actual environmental noise and unnecessary noise and evaluate the performance of the communication system.

Further, according to claim 7, in addition to the effect of claim 1, when a modulated signal subjected to spread spectrum modulation by frequency hopping is used as noise, noise can be easily generated by changing the number of hoppings. Since the power density can be changed arbitrarily, it is possible to easily create actual environmental noise and unnecessary noise and evaluate the performance of the communication system.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a communication performance evaluation apparatus according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram showing a data generator for noise generation according to the first embodiment of the present invention.

FIG. 3 is a configuration diagram showing a communication performance evaluation device according to a second embodiment of the present invention.

FIG. 4 is a diagram showing a comparison between the measurement result of the BER characteristic in the second embodiment of the present invention and the result of the BER characteristic by the conventional method.

FIG. 5 is a configuration diagram showing a communication performance evaluation device according to a third embodiment of the present invention.

FIG. 6 is a diagram showing measurement results of BER characteristics according to the third embodiment of the present invention.

FIG. 7 is a configuration diagram showing a communication performance evaluation device according to a fourth embodiment of the present invention.

FIG. 8 is a configuration diagram showing a communication performance evaluation device according to a fifth embodiment of the present invention.

[Explanation of symbols]

101,108 ... Data generator (for noise generation), 102,110 ...
Carrier wave generator, 103, 106, 111 ... Mixer, 104, 107, 112, 4
10,510,610 ... Band pass filter, 105,109 ... Amplifier, 11
3,305,405,411,505,511,611,614-1 to 614-n ... Variable amplifier, 114,303,403,503,603 ... Transmitting device (communication system to be evaluated), 115,119,308,408,413,508,514,604,605 ...
Directional coupler, 116,301,401,501,601 ... Data generator (for communication signal), 117,122,302,311,402,416,502,517,60
2,608 ... Memory, 118,409,509,609 ... Gaussian noise generator, 120,309,414,515,606 ... Receiver (evaluation target communication system), 121,310,415,516,607 ... Data receiver, 2
01 ... Data generator (for noise generation), 202,213,214 ... Mixer, 203,215 ... Sin wave generator, 204,208,512,612 ... Switch, 205 ... Variable amplifier, 206,217 ... Frequency synthesizer, 207 ... Phase converter, 209,218 ... Amplifier, 210,219
… Band pass filter, 211,220… Output terminal, 212,216… P
N code generator, 304,404,504,613-1 to 613-n ... Signal generator, 306,307,406,407,412,506,507,513,615-1 to 615-n, 6
16,617… Power measurement device.

─────────────────────────────────────────────────── --- Continuation of the front page (56) References JP-A-58-156870 (JP, A) JP-A-11-97937 (JP, A) JP-A-10-145274 (JP, A) JP-A-4- 292028 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H04B 17/00 H04J 13/00 H04L 27/02 H04L 27/10 H04L 27/18

Claims (7)

(57) [Claims] 1. Amplitude shift keying (A)
SK, Frequency Shift Keying (FS)
K), phase modulation (Phase Shift Keying: PSK), and spread spectrum modulation (Spread Spectrum: SS) for communication systems that perform wireless communication and telecommunication by using communication signals generated using digital modulation such as In a communication performance evaluation device that evaluates communication performance based on a scale such as a bit error rate (BER), a single or a plurality of modulated signals using digital modulation such as amplitude modulation, frequency modulation, phase modulation, and spread spectrum modulation. A communication performance evaluation apparatus comprising: a noise injection unit that injects the modulated signal of 1. 2. The noise injecting means changes a frequency band of the modulation signal, a frequency band changing means, a modulation rate changing means for changing a modulation rate of the modulation signal, and an intensity for changing an intensity of the modulation signal. The communication performance evaluation apparatus according to claim 1, further comprising a variable unit. 3. The communication performance evaluation apparatus according to claim 1, further comprising Gaussian noise injection means for injecting white Gaussian noise into the communication signal. 4. The noise injection unit has a noise generation unit that generates noise based on intensity information and phase information of noise radiated from a specific electronic device that has been actually measured, and the noise generated by the noise generation unit. 2. The communication performance evaluation device according to claim 1, wherein is injected into the communication signal. 5. The noise injecting means changes the power density of the modulation signal by fixing the center frequency and the signal pass bandwidth and changing the value of M when performing M-value FSK modulation or M-value PSK modulation. The communication performance evaluation device according to claim 1, wherein 6. The noise injecting means, when performing spread spectrum modulation by direct spreading, fixes the center frequency and the signal pass bandwidth and makes the operating frequency of the spreading code the same to change the spreading code length. The communication performance evaluation apparatus according to claim 1, wherein the power density of the signal is changed. 7. The noise injecting means changes a power density of the modulated signal by fixing a signal occupied bandwidth and changing a hop number when performing spread spectrum modulation by frequency hopping. Item 1. The communication performance evaluation device according to item 1.