JP2000196540A - Radio wave environment analysis device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a radio wave environment analysis device that can simultaneously measure an arrival azimuth of an incident signal, a propagation delay time and relative power and that is suitable for mobile communication environment regardless of a simple hardware configuration. SOLUTION: A transmission antenna 27 of a transmitter 11 emits a transmission signal that is biphase-shift keyed by using a PN code stream and an array antenna 32 of a receiver receives the signal, outputs of a plurality of antenna elements are sequentially selected, the selected signal is ANDed with a signal 42 that is fed from a PN code generator 41, consisting of the same code stream as the received transmission signal but with a slightly different transmission rate so as to apply inverse spread processing to the received signal, the result is converted into a base band signal and is quadrature detected. This quadrature detected signal is given to a signal processing unit 13, where the signal is displayed as a delay profile representing a relation between a delay time and a power of the quadrature detected signal, and the arrival azimuth can be calculated by designating a time to analyze the arrival azimuth, resulting that a PDA-gram is displayed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio wave environment analyzer for analyzing a signal incident on an array antenna in which antenna elements are arranged in a straight line, and more particularly, to an arrival direction, a propagation delay time and a relative power of an incident signal. The present invention relates to a radio wave environment analyzer that can measure simultaneously.

[0002]

2. Description of the Related Art From the relation of a specific band (frequency / bandwidth),
The higher the frequency, the wider the bandwidth, and a larger number of channels can be secured. Therefore, in order to realize high-speed digital mobile radio communication, use of a high frequency band that can essentially secure a wide transmission band is being studied. However, the power required for the mobile communication system is proportional to the transmission bandwidth and proportional to the 2.6th power of the frequency. Therefore, realizing broadband transmission using high frequencies requires enormous power. For this reason, a mobile communication system in which a high gain is obtained by narrowing the beam of the antenna of the base station and the required power is reduced has been studied.

[0003] Such a mobile communication system estimates an azimuth of a terminal as viewed from a base station, directs a narrow antenna beam in the direction, and enhances an antenna such that the antenna beam tracks as the terminal moves. To achieve.

In general, as the transmission speed increases, the shift of information bits becomes relatively large even with the same transmission delay. For this reason, equalization in the time domain, that is, compensation for a time delay becomes difficult with the conventional method. Therefore, in a mobile communication system, introduction of an adaptive antenna (adaptive antenna) for removing an interference signal by a spatial filter is being studied.

[0005] By the way, the problem of interference cancellation and equalization in a mobile communication system has been conventionally studied in the time domain. That is, the elucidation of the multipath propagation structure including not only the main wave directly incident on the receiving antenna but also the multipath wave reflected on an obstacle has conventionally been limited to the time domain due to a low bit rate. However, the role of the antenna as a spatial filter has become important along with the increase in transmission speed as described above. Therefore, it is necessary to clarify the multipath propagation structure in the spatial domain in addition to the time.

An example of elucidating the multipath propagation structure in the time and space domains is described in the document “High Resolution Analysis of In
door Multipath Propagation Structure: IEICE Tran
s. Vol.E78B, No. 11, 1995 ”. In this document, the arrival direction, propagation delay time, and relative power of the main wave and the multipath wave are described by MUSIC (MUltiple SIgna).
(1) Classification) The theory and experimental results estimated using the method are described.

[0007]

However, according to the technique disclosed in this document, since a network analyzer is used, it is necessary to lay a cable between transmission and reception and to input a part of a transmission signal as a reference signal of the network analyzer. is there. Therefore, there is a first problem that measurement is greatly restricted in an outdoor mobile communication environment.

Next, according to the method of this document, it is necessary to mechanically move the position of the receiving antenna and acquire data at a plurality of positions. Therefore, as a second problem, the mechanical movement and position setting of the receiving antenna increase the measurement time. In addition, a complicated NC control mechanism is required, which impairs economic efficiency.

Further, according to the method of this document, a two-dimensional M
Using the 2D-MUSIC method as the USIC method, 2
A dimension evaluation function spectrum is drawn. Therefore, as a third problem, there is a problem that the amount of calculation becomes enormous and processing time is required. Further, in the method of this document, the estimation of the angle is limited to either the azimuth or the elevation angle. Therefore, as a fourth problem, considering that the base station of the currently operating mobile phone controls the directivity of the elevation surface of the antenna according to the situation, both the azimuth and the elevation angle are changed. There is a problem that measurement cannot be performed in the same way.

Further, conventionally, the arrival direction of an incident signal,
Although there is an apparatus for measuring the propagation delay time and the relative power independently, an apparatus for measuring them at the same time has not been commercialized. Therefore, it is difficult to associate and analyze the results even when attempting to use several conventional devices in combination, and to analyze the accurate radio wave environment due to the individual differences of the antennas and the like used for each device. Could not. Needless to say, there has not been any technical request until such three-party analysis has been performed in the past, and a proposal for responding to such a request is the above-mentioned document.

Accordingly, an object of the present invention is to provide a radio wave environment analyzer capable of simultaneously measuring the arrival direction, propagation delay time, and relative power of an incoming signal with a simple hardware configuration suitable for a mobile communication environment. It is in.

[0012]

According to the first aspect of the present invention, there is provided (a) a transmitting means for radiating a transmission signal subjected to two-phase shift keying with a PN code sequence from a transmitting antenna, and (b) the transmitting means. An antenna receiving the transmission signal transmitted by the plurality of antenna elements, a signal selecting means for selecting and extracting one signal from the array antenna,
Despreading means for despreading by taking the product of the signal selected by the signal selection means and a signal having the same code sequence as the transmission signal and having a slightly different transmission rate, and intermediately despreading the signal despread by the despreading means. Receiving means having quadrature detection means for converting to a frequency or baseband signal, quadrature detection and outputting as a quadrature detection signal, and (c) supply of a switching signal for supplying a switching signal for signal selection to the signal selection means Means, storage means for digitizing and storing a quadrature detection signal obtained by supplying the switching signal and obtained from the quadrature detection means, and a quadrature detection signal obtained by reception by a predetermined antenna element in the array antenna Delay profile display means for displaying a delay profile representing the relationship between the power and delay time of the power supply, and a delay profile displayed on the delay profile display means. Time designating means for designating a time for analyzing the direction of arrival from the file, extracting means for extracting a signal at the time designated by the time designating means from the digitized quadrature detection signal stored in the storage means, And a signal processing unit having an arrival direction calculation unit for estimating the arrival direction by estimating the covariance matrix of the reception signal of the array antenna at the time.

That is, according to the first aspect of the present invention, the receiving means for receiving, from the transmitting antenna, the transmission signal subjected to the two-phase shift keying with the PN code sequence prepares an array antenna having a plurality of antenna elements. . Then, the signals to be received by these antenna elements are switched and selected by the signal selecting means, and despreading is performed by multiplying the selected signal by a signal having the same code sequence as the transmission signal and a slightly different transmission speed. The obtained signal is converted into an intermediate frequency or baseband signal, subjected to quadrature detection, and output as a quadrature detection signal. The signal processing means stores the quadrature detection signal in the storage means and displays a delay profile representing the relationship between power and delay time based on the reception result of each antenna element. In these delay profiles, each peak value of the received multipath wave is indicated, and the one to be analyzed is designated by the time designating means, and the quadrature detection signal obtained by a plurality of antenna elements is designated. The direction of arrival of the designated wave is calculated by the direction of arrival calculation means from the data, and the radio wave environment is analyzed by simultaneously measuring the direction of arrival, propagation delay time, and relative power of the incoming signal as described above. Like that.

According to the second aspect of the present invention, (a) transmitting means for radiating a transmission signal subjected to two-phase shift keying with a PN code sequence from a transmitting antenna, and (b) a transmission signal transmitted by the transmitting means. Antenna, a signal selecting means for selecting and extracting one signal from the array antenna, and a signal selected by the signal selecting means and the same code sequence as the transmission signal are slightly transmitted. Despreading means for despreading by taking the product of signals having different speeds, and quadrature detection means for converting the signal despread by the despreading means to an intermediate frequency or baseband signal, quadrature detection and outputting as a quadrature detection signal Receiving means comprising: (c) a switching signal supplying means for supplying a switching signal for signal selection to the signal selecting means; And the storage means for digitizing and storing the quadrature detection signal obtained from the quadrature detection means and the relationship between the power and the delay time of the quadrature detection signal obtained by reception by a predetermined antenna element in the array antenna. Delay profile display means for displaying a delay profile; time designating means for designating a time for analyzing an arrival direction from the delay profile displayed on the delay profile display means; and a digitizing quadrature detection signal stored in the storage means. Extracting means for extracting a signal at a time designated by the time designating means from among them; an arrival direction calculating means for estimating a covariance matrix of a received signal of an array antenna at a designated time to obtain an arrival direction; PDA graph for displaying a PDA graph as a graph showing relative power, propagation delay time and direction of arrival of a signal To and a signal processing means and display means in the radio environment analysis apparatus.

That is, according to the second aspect of the present invention, the receiving means for receiving from the transmitting antenna the transmission signal subjected to the two-phase shift keying with the PN code sequence prepares an array antenna having a plurality of antenna elements. . Then, the signals to be received by these antenna elements are switched and selected by the signal selecting means, and despreading is performed by multiplying the selected signal by a signal having the same code sequence as the transmission signal and a slightly different transmission speed. The obtained signal is converted into an intermediate frequency or baseband signal, subjected to quadrature detection, and output as a quadrature detection signal. The signal processing means stores the quadrature detection signal in the storage means and displays a delay profile representing the relationship between power and delay time based on the reception result of each antenna element. In these delay profiles, each peak value of the received multipath wave is indicated, and the one to be analyzed is designated by the time designating means, and the quadrature detection signal obtained by a plurality of antenna elements is designated. The arrival direction of the designated wave is calculated from the data by the arrival direction calculation means, and the arrival direction, propagation delay time and relative power of the incident signal are simultaneously measured as described above, and the result is displayed on the PDA gram display means. The data is displayed as a PDA gram to enable analysis of the radio wave environment. Note that the display here is a concept that includes not only a case where the image is visually displayed on a display but also a case where the image is displayed on a sheet of paper by a printer. The same applies to the invention described in claim 4 described later.

According to the third aspect of the present invention, (a) transmitting means for radiating from a transmitting antenna a transmission signal subjected to two-phase shift keying with a PN code sequence, and (b) a transmission signal transmitted by the transmitting means. Antenna with multiple antenna elements, and the product of the signal received by each of the multiple antenna elements of the array antenna and the signal with the same code sequence as the transmission signal and a slightly different transmission rate are individually despread. Despreading means, and quadrature detection means for converting each signal despread by the despreading means into an intermediate frequency or baseband signal, quadrature-detecting and outputting as a quadrature detection signal corresponding to each antenna element and outputting the same. Receiving means, and (c) storage means for digitizing and storing a plurality of orthogonal detection signals corresponding to each antenna element obtained from the orthogonal detection means. Delay profile display means for displaying a delay profile representing the relationship between the power of the quadrature detection signal received by each antenna element and the delay time, and an arrival direction is analyzed from the delay profile displayed on the delay profile display means. Time designating means for designating a time to be performed, extracting means for taking out a signal of the time designated by the time designating means from the digitized quadrature detection signal stored in the storage means, and an array antenna of the designated time. The radio wave environment analyzing apparatus is provided with signal processing means having a direction of arrival calculating means for estimating a direction of arrival by estimating a covariance matrix of a received signal.

That is, the invention described in claim 3 is based on claim 1.
According to the invention described above, processing until obtaining a quadrature detection signal is made independent for each antenna element constituting an array antenna. As a result, although the circuit configuration of the radio wave environment analyzer becomes complicated, it is possible to speed up data processing as compared with time-division processing, and to improve data reliability.

According to the fourth aspect of the present invention, (a) transmitting means for radiating from a transmitting antenna a transmission signal subjected to two-phase shift keying with a PN code sequence, and (b) a transmission signal transmitted by the transmitting means. Antenna with multiple antenna elements, and the product of the signal received by each of the multiple antenna elements of the array antenna and the signal with the same code sequence as the transmission signal and a slightly different transmission rate are individually despread. Despreading means, and quadrature detection means for converting each signal despread by the despreading means into an intermediate frequency or baseband signal, quadrature-detecting and outputting as a quadrature detection signal corresponding to each antenna element and outputting the same. Receiving means, and (c) storage means for digitizing and storing a plurality of orthogonal detection signals corresponding to each antenna element obtained from the orthogonal detection means. Delay profile display means for displaying a delay profile representing the relationship between the power of the quadrature detection signal received by each antenna element and the delay time, and an arrival direction is analyzed from the delay profile displayed on the delay profile display means. Time designating means for designating a time to be performed, extracting means for taking out a signal of the time designated by the time designating means from the digitized quadrature detection signal stored in the storage means, and an array antenna of the designated time. Arrival direction calculating means for estimating the direction of arrival by estimating the covariance matrix of the received signal, and PDA gram display means for displaying a PDA gram as a graph showing the relative power, propagation delay time and direction of arrival of the plurality of arriving signals. The radio wave environment analyzer is provided with the provided signal processing means.

That is, the fourth aspect of the present invention corresponds to the second aspect of the present invention, and the processing until the quadrature detection signal is obtained is made independent for each antenna element constituting the array antenna. As a result, although the circuit configuration of the radio wave environment analyzer becomes complicated, it is possible to speed up data processing as compared with time-division processing, and to improve data reliability.

According to a fifth aspect of the present invention, in the radio wave environment analyzing apparatus according to the first to fourth aspects, the array antenna of the receiving means has a plurality of antenna elements arranged in a straight line, and the signal processing means has It is characterized by estimating the horizontal angle or the elevation angle.

According to the sixth aspect of the present invention, there is provided the first aspect.
The array antenna of the receiving means in the radio wave environment analyzer according to any one of claims 1 to 4, wherein a plurality of antenna elements are arranged in a matrix on a plane, and the signal processing means estimates a horizontal angle and an elevation angle. It is characterized by:

Further, in the invention according to claim 7, according to claim 1,
The array antenna of the receiving means in the radio wave environment analyzing apparatus according to any one of claims 1 to 4, wherein a linear array antenna in which a plurality of antenna elements are arranged in a straight line, and a planar array antenna in which a plurality of antenna elements are arranged in a matrix on a plane. It is characterized by being comprised from.

Further, according to the invention described in claim 8, according to claim 7,
The array antenna of the receiving means in the described radio wave environment analyzer includes a linear array antenna in which a plurality of antenna elements are arranged in a straight line, and a planar array antenna in which a plurality of antenna elements are arranged in a matrix on a plane. The signal processing means is provided with an array antenna selecting means for selecting one of the array antennas.

Further, according to the ninth aspect of the present invention, the first aspect is provided.
According to a fourth aspect of the present invention, in the radio wave environment analyzer, the arrival direction calculation means estimates the arrival direction by an eigenvalue decomposition method.

According to a tenth aspect of the present invention, in the radio wave environment analyzer according to the first to fourth aspects, the arrival direction calculating means estimates the arrival direction based on the principle of an interferometer.

According to the eleventh aspect of the present invention, in the radio wave environment analyzer according to the ninth aspect, the MUSIC method is used as an eigenvalue decomposition method for the arrival direction, propagation delay time, and relative power of the main wave and the multipath wave. It is characterized by using Eq.

According to a twelfth aspect of the present invention, in the radio wave environment analyzer according to the ninth aspect, the ESPRIT method is used as an eigenvalue decomposition method for the arrival direction, propagation delay time and relative power of the main wave and the multipath wave. It is characterized by using Eq.

Further, in the invention according to claim 13, in the radio wave environment analyzing apparatus according to claims 1 to 4, the arrival direction calculating means has a plurality of algorithms for calculating the direction of arrival, and performs signal processing. The means is provided with an algorithm selecting means for selecting any one of the algorithms.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 1 shows the configuration of a radio wave environment analyzer according to an embodiment of the present invention. This device is
It comprises a transmitting device 11, a receiving device 12, and a signal processing device 13. The transmitting device 11 transmits B
This is a device that repeatedly transmits a PN (pseudo noise) code subjected to PSK modulation (two-phase shift keying). Where BP
The SK modulation refers to a method of transmitting the phase (0, π) of a carrier in correspondence with “0” or “1” as input data.

FIG. 2 is for explaining BPSK modulation. When the PN code shown in (b) changes between "0" and "1" with respect to the RF signal shown in (a) in the same figure, as shown in (c) in FIG. The RF signal shown in (a) is inverted.

Returning to FIG. The receiving device 12 is a device that receives a transmitted PN code by a plurality of antenna elements in a time-division manner, despreads each signal, converts the frequency, performs quadrature detection, and outputs the result. The signal processing device 13 displays the propagation delay time and the relative power from the quadrature detection output of each antenna element in the reception device 12, and estimates the arrival angle as the angle of the arrival direction of the radio wave at the reception point. It is a device that outputs the result.

The transmitting device 11 includes a PN code generator 21 and a carrier generator 22. PN code generator 21
N code sequences are generated at a constant cycle. Carrier generator 22
Generates a carrier wave of a measurement frequency.
These outputs are input to a multiplier 23 and multiplied by BP.
SK modulation is performed. The output of the multiplier 23 is input to the first bandpass filter 24, and the output is band-limited to a predetermined measurement band. The output of the first bandpass filter 24 is input to the power amplifier 25 and power-amplified until it reaches a predetermined power. The transmission signal 26 composed of the PN code after the power amplification is radiated from the transmission antenna 27 into space.

On the other hand, the receiving apparatus 12 includes an array antenna 32 in which a plurality of antenna elements 31 ₁ , 31 ₂ ,..., 31 _N are arranged. For the array antenna 32 is for estimating the arrival direction, and a different one for receiving and installing the antenna into a plurality of positions, the plurality of antenna elements 31 ₁ Therefore, 31 _2, ...... 31 _N . The PN code signal 26 radiated from the transmitting device 11 is received by the array antenna 32. The array antenna 32 is
Are connected to respective antenna elements _{31 1, 31 2, ...... 31} N changeover switch 33 for selectively alternatively receive output. 1 selected by the changeover switch 33
The two reception outputs 34 are input to a second bandpass filter 35 and are limited to a predetermined reception band.

The weak reception signal 36 that has passed through the second bandpass filter 35 is input to an LNA (low noise amplifier) 37 and amplified with low noise. The amplified signal 38 is input to one input terminal of a first multiplier 39. The other input terminal of the first multiplier 39 receives a signal from the PN code generator 41
The N code sequence 42 is input. This P
The N code sequence 42 is generated by repeating the same PN code sequence as that of the transmitting device 11 at a slightly different transmission speed. The first multiplier 39 performs despreading by multiplying the output of the LNA 37 and the output of the PN code generator 41.

The despread signal 43 is input to a third bandpass filter 44 and is limited to a predetermined band. The despread signal 45 band-limited by the third band filter 44 is input to one input terminal of a second multiplier 46. The other input terminal of the second multiplier 46 is supplied with a local oscillation signal 48 for performing frequency conversion to an intermediate frequency from a signal generator 47. The second multiplier 46 performs frequency conversion by mixing the despread signal 45 and the local oscillation signal 48. The frequency-converted intermediate frequency signal 49 is band-limited by a fourth band-pass filter 51, and is input to a logarithmic amplifier (LOG) 53 as an intermediate frequency signal 52. The logarithmic amplifier 53 logarithmically compresses the intermediate frequency signal 52. The limiter output 54 of the logarithmic amplifier 53 is input to a quadrature detector 55, where quadrature detection is performed.

The signal processing device 13 has a CPU (central processing unit) 61 for performing various controls in the device. The CPU 61 includes first to third FIFOs (first-in first-out memories) 63 to 65 via a data bus 62, a main memory (MEM) 66, and an input / output interface (I
/ O) 67. The CPU 61 performs processing according to a program stored in the main storage device 66.
The input / output interface 67 is also connected to the input / output device 69, and performs an interface with the CPU 61. Further, as described later, a switching signal 68 for time division reception is transmitted to the receiving device 12 based on the synchronization output of the PN code generator 41 of the receiving device 12. It should be noted that a relatively inexpensive desktop or laptop computer can be used for the signal processing section such as the CPU 61.

The signal processing device 13 inputs the quadrature detection outputs 71 and 72 from the quadrature detector 55 in the receiving device 12 to corresponding ones of the first and second A / D converters 73 and 74, and also performs logarithmic amplifier. The logarithmic compression output 75 of 53 is input to a third A / D converter 76. As a result, the three types of analog-to-digital converted signals are:
The first to third FIFO memories 63 to 65 are temporarily stored. The respective quadrature detection outputs or logarithmic compression outputs stored in the first to third FIFO memories 63 to 65 are displayed on the input / output device 69 as a delay profile. When the input / output device 69 is operated to specify the propagation delay time for the reflected wave to be analyzed, the CPU 61 outputs the quadrature detection output or logarithmically compressed output temporarily stored in the first to third FIFO memories 63 to 65. Then, the direction of arrival is estimated using the eigenvalue decomposition method or the principle of an interferometer. This is similarly output to the input / output device 69.
The contents output to the input / output device 69 will be described later in detail.

FIG. 3 shows the principle of operation of the delay profile measurement. The delay profile is obtained by a sliding correlation of the PN code. This will be described briefly. It is assumed that a transmission signal 26 as shown in FIG. 3A is output from the transmission device 11 shown in FIG. The pulse waveform shown in this figure represents time-series data of "1" and "-1". Since the sine wave is BPSK-modulated, when the pulse is "1", the phase shift of 0, that is, the phase of the sine wave is In the state of "-1", the phase shifts by 180 degrees and the sine wave waveform is inverted.

The transmission signal 26 shown in FIG.
This is a signal in which three-stage M-sequence codes are BPSK-modulated and transmitted repeatedly at a period T. Here, the PN “n” stage (n is a positive integer) indicates a PN code sequence length, and indicates a bit length of 2 ⁿ . In the PN3 stage, the bit length is 2 ³ (= 8). P
The N3-stage M-sequence code is the longest sequence that can be generated by using the output of each stage of the three-stage shift register as a feedback tap and feeding back to the input of the first-stage shift register.

In receiving apparatus 12 in FIG. 1, the same code sequence as in transmitting apparatus 11 is generated due to despreading. Receiving device 1
2 and the transmission device 11, the PN code sequence 42 output from the PN code generator 41 is matched as shown in FIG. 3B, and the signal is despread as shown in FIG. As a result, the same code sequence as that of the despreading (CW) signal 45, that is, the transmitting apparatus 11, is obtained.

FIG. 3D shows a PN code when the receiving device 12 and the transmitting device 11 are asynchronous. In the case of non-synchronization, as a result of despreading the pulse waveform shown in FIG. 9D and the sine wave shown in FIG. 9A, an inverse BPSK modulated with a random code as shown in FIG. A spread signal is obtained.

FIGS. 4 and 5 are for explaining the spectrum of the despread signal, and FIG. 4 shows the state of the filter output at the time of synchronization. P between sending and receiving
When the synchronization of the N codes is established, the frequency spectrum coincides with the specific frequency f _{0 as shown} in FIG. As a result, assuming that the frequency of the narrow band-pass filter is in the range between the frequencies f _p1 and f _p2 sandwiching this frequency f ₀ as shown in FIG. those without loss to a specific frequency f ₀ as the filter output is obtained, a high power spectrum at a carrier frequency.

FIG. 5 shows an asynchronous case. In the asynchronous case, the power spectrum is spread as shown in FIG. For this reason, the average power per frequency is reduced, and when passing through a narrow band-pass filter in the range of frequencies f _p1 and f _p2 as shown in FIG. Only very low filter output is obtained. As described above, if the signal after despreading is passed through a very narrow band-pass filter that passes only near the carrier frequency as shown in FIG. 4 and FIG. Diffusion (CW)
When the signal 45 is obtained, but the synchronization is lost, the output becomes negligibly small.

The starting point of the PN code sequence of the receiver 12 is
It is simulated on the time axis. Therefore, the receiving device 12
The transmission rate of the PN coded sequence generated in
Slightly shifted from that of 1. This will be described below.

FIG. 6 (a) shows a PN encoded sequence of the transmitting device, and FIG. 6 (b) shows a PN encoded sequence of the receiving device. As shown in FIG. 9A, during the time TT during which the transmitting apparatus 11 transmits the PN code sequence “3001”, the receiving apparatus 12 performs “300” for despreading.
A PN code sequence of "0" is generated. At this time,
The k factor of the sliding correlation is “3000 / (3
001-3000) = 3000 ″.

This will be described briefly. The PN code is obtained by repeating the same pseudo-random code sequence at a constant period and outputting the same. Therefore, when performing despreading, P
By slightly changing the transmission rate of the N code from that of the transmitting side, the code sequence of the PN code can be performed a certain number of times (here, 3
000 times), the PN code is synchronized every time
The F signal is extracted as a correlation coefficient between both PN codes. The number of repetitions of the pseudo-random code sequence in this case is called a k-factor. In addition, a method in which despreading is performed with a PN coded sequence having a slightly different transmission speed so that an RF signal can be extracted as a PN code correlation coefficient for each k factor is called a sliding correlation method.

FIG. 6C shows a sliding correlation output. The sliding correlation output appears as a triangular wave. The correlation output peaks at the point of complete synchronization, and the correlation output attenuates as synchronization is lost.
The filter output of the despread signal has the same output waveform.

In an actual delay profile measuring apparatus, as will be described later in an embodiment, for example, an M-system code string of PN9 stages is used. At this time, the time required from the rising of the triangular wave to reach the peak and the time required to fall from the peak to the base level are respectively t / 2.
Is 1/511 of the time TT required for the repeated transmission of “3001” for the transmission PN sequence. This value is obtained as a result of a predetermined operation.

The receiver 12 for delay profile measurement outputs a synchronization pulse once every time a PN code sequence of “3000” is generated as a synchronization signal for observing the delay profile. The received multipath signal having various delay times and reception electric fields is displayed on the oscilloscope (not shown) with an amplitude proportional to the reception electric field at a timing corresponding to the delay amount on the X axis, and the delay profile is displayed. be painted. The time displayed on the oscilloscope is k times the actual propagation delay. The maximum measurement distance is 1
When a 00 Mbps PN code is used, the time TT shown in FIG. 6 is 15.33 ms, and the time TT shown in FIG.
Becomes 15.33 [ms] × 30 [10,000 km] / 300
0 = 1533 [m]

FIG. 7 shows the principle of measurement of the angle of arrival. Here, for the sake of simplicity, it is assumed that the receiving antenna is a three-element array antenna having an evenly spaced linear array. That is, the first to third antenna elements 31 ₁ , 3
1 ₂ and 31 ₃ are linearly arranged at regular intervals, and the changeover switch 33 switches these in order. It is assumed that the arrival angle is represented by angles of right and left θ ₁ and θ ₂ with respect to the direction of the linear arrangement of these antenna elements 31 ₁ , 31 ₂ and 31 ₃ and the vertical direction.

Now, in the receiving device 12 (FIG. 1), FIG.
As shown in (a), “30” used for despreading is used.
FIG. 8B shows the timing of the generation of the synchronization signal output every time TT that coincides with the repetition period of the PN code “00”.
, The first to third antenna elements 31 ₁ , 31 ₂ ,
31 ₃ sequentially switched to receive.

FIG. 9 shows an output state of the signal processing device. As shown in FIGS. 9A to 9C, the vertical axis represents the power and the horizontal axis represents the time cursor (t).
As the first to third antenna elements 31 ₁ , 31 ₂ , 31 ₃
Can be drawn for each of. The delay profile is the view corresponding to the first antenna element 31 ₁ in the figures (a), the delay profile corresponding to the second antenna element 31 ₂ in FIG. (B), the third antenna element 3
Delay profile corresponding to 1 ₃ are respectively shown in FIG. (C). In these figures, symbols X _{1 to} X ₃ indicate the received signal level on the cursor line 81, and the expression X ₁ = A
The symbol A in e ^{j φ 1} represents the amplitude.

The time of the multipath signal appearing in the delay profile is measured, and the reception signals (X _{1 to} X ₃ ) of the first to third antenna elements 31 ₁ , 31 ₂ , and 31 ₃ at that time are measured.
A covariance matrix (correlation matrix) S is calculated by the S matrix 82, and based on the principle of the eigenvalue decomposition method or the interferometer, the one-dimensional arrival angle estimation shown in FIG. The estimation 83 of the angle of arrival is performed by the two-dimensional angle of arrival estimation shown in FIG. It should be noted that a plurality of antenna elements 31 ₁ , 31 ₂ , and 31 ₃ are used because a plurality of antenna elements are required to obtain the angle of arrival from the delay profile, and to obtain a large number of angles of arrival. This is because more antenna elements are required.

Here, the eigenvalue decomposition method includes the MUSIC method and E
SPRIT (Estimation of SignalParameters via Rot
Techniques such as the ational Invariance Techniques method exist. The interferometer is a method of obtaining the direction of arrival using the time difference between plane waves arriving at the array antenna. These are described in the document “Multiple EmitterLo.
cation and Signal Parameter Estimation: IEEE Tran
s. on Antennas and Propagation Vol. AP-34, No.3, p
p276-280, Mar. 1986 ”,“ ESPRIT-Estimation of Signa
l Parameters via Rotational Invariance Techniques:
IEEE Trans.on Acoustics, Speech and Signal Proces
sing Vol.37, No.7, pp984-995, July. 1989 ”,“ Development of vehicle position locating technology in automatic toll collection system: IEICE, Vol.J81-A No.4 pp475-182 April 1998 Month ".

When it is considered that a plurality of signals arrive at the same time, the eigenvalue decomposition method must be used. This is because the interferometer can only estimate the direction of arrival of the wave. In other cases, an interferometer can also be used. In the eigenvalue decomposition method, the relative power can also be estimated. In this case, the arrival angles and relative powers of a plurality of multipath signals having the same delay time are obtained. Therefore, by using the delay profiles of the _first to third antenna elements 31 ₁ , 31 ₂ , and 31 ₃ , a PDA gram (Power Delay Angle gram) showing a multipath propagation structure as shown in FIG. Can be drawn. Here, the PDA gram is a graph showing relative power (Power), propagation delay time (Delay), and arrival direction (Angle) of a plurality of incoming signals.

In FIG. 8F, the vertical axis indicates the relative power P, and the horizontal axis indicates the propagation delay time t. The inclination θ from the vertical axis indicates the arrival direction. Each vertical line segment 85 indicates these three values of each reflected wave (multipath other than the main wave).

When there is no Doppler shift, or when estimating the direction of arrival of a multipath multiple signal having a propagation delay amount equal to or less than the chip rate (1 bit or less of data), a moving average is applied to the covariance matrix. Apply the eigenvalue variance method. Here, the moving average is a method of dividing the covariance matrix into small matrices of the same dimension and taking the average of the small matrices. For details of the moving average, see “On Spatial Smoothing for
Direction of ArrivalEstimation of Coherent Signal
s: IEEE Trans.on Acoustics, Speech and Signal Pro
cessing Vol. 33, No. 4, pp. 806-811, Aug. 1986 ".

When the moving average is applied, the number of effective array elements is halved. Therefore, in order to estimate the direction of arrival at the same time as the perfect correlation signal of the M wave, an array antenna of 2M elements equal to twice is required. Also, when an array antenna is used in the DOA estimation, the signal received by the antenna element is different from the received signal when only one element is placed at the position where the antenna element is arranged due to the effect of coupling between elements. Different results are obtained. When the moving average is applied by the eigenvalue decomposition method, the eigenvalue analysis is performed in a state where the received signal is multiplied by the inverse matrix of the inter-element coupling matrix and the inter-element coupling component is removed.

If the two-dimensional unitary ESPRIT method is applied with the receiving antennas arranged in a plane array, a two-dimensional angle can be estimated. For details of the two-dimensional unitary esprit method, see “Closed Form 2D Angle Estimation with Rectangul”.
ar Arrays in Element Space or Beamspace via Unitar
y ESPRIT: IEEE Trans.on Signal Processing Vol.44,
No. 2, pp. 316-328, Feb. 1996 ”.

[0061]

【Example】

Hereinafter, the present invention will be described in detail with reference to examples.

FIG. 10 shows the configuration of a radio wave environment analyzer according to one embodiment of the present invention. The radio wave environment analyzer includes a transmitting unit 101, a receiving antenna unit 102, a receiving unit 103, and a signal processing unit 104.
The transmitting unit 101 includes a transmitter 111 of a multiplexed wave delay measuring device,
The transmitter 111 includes a rubidium oscillator 113 for supplying a reference clock 112 to the transmitter 111 and a transmission antenna 115 for radiating a transmission signal 114 output from the transmitter 111 into space. The transmission signal 114 is PN
This is a signal obtained by BPSK-modulating a nine-stage M code sequence. The carrier frequency is 2.2 GHz (gigahertz) and the data transmission rate is 150.05, 100.033, 50.01.
7, 12.504 Mbps (megabits / second). In this embodiment, the measurement of the delay profile is performed by a multi-wave delay measuring device ME2636C manufactured by Anritsu Corporation.
A mold is used, but other similar devices may be used.

The receiving antenna constituting the receiving antenna section 102 is provided with two types of a linear array antenna 121 for estimating a one-dimensional angle of arrival and a planar array antenna 122 for estimating a two-dimensional angle of arrival. . Each of the antennas 121 and 122 has 16 antenna elements 12
1 _{01-121 16,} 122 _{01-122 16} is constituted by, those in the first or second change-over switch 123 and 124 is adapted to be alternatively selected. The receiving antenna unit 102 includes first and second changeover switches 12
A third changeover switch 125 for selecting the output side of the interface circuit 12 is provided.
6, the reception output 131 of one antenna element is output from the reception antenna unit 102 in accordance with the switching signals 127 to 129 supplied to these changeover switches 123 to 125.

The linear array antenna 121 includes first to first
Sixth antenna element 121₀₁~ 121 ₁₆Directly in half wavelength units
They are arranged on a line. Planar array antenna 1
22 is a first to sixteenth antenna element 122₀₁~ 122
₁₆4 elements on the vertical plane, 4 elements on the horizontal plane
They are arranged in a grid pattern at intervals. Third switch
The switching signal 129 supplied to the switch 125
These linear array antennas 121 having different arrangements of
Whether to use the flat array antenna 122 or
Will be used to switch accordingly.

The switching signals 127 and 128 supplied to the first and second changeover switches 123 are TDM (Time Divide).
ision Multiplexing (Time Division Multiplexing)
Sixteenth antenna elements 121 _{01 to} 121 ₁₆ , 122 ₀₁ to
122 ₁₆ is used for selecting whether to receive either the output of. The interface circuit 126 performs switching timing for TDM reception generated in the signal processing unit 104,
A designated address of an antenna element to be received and a designated signal of an estimated dimension of an angle of arrival are received, converted into switching signals 127 to 129 necessary for the first to third changeover switches 123 to 125, and output. I have.

The receiving section 103 includes a receiver 141 of the above-described multiplexed wave delay measuring device and a rubidium oscillator 142 for supplying a reference clock to the receiver 141. The receiver 141 of the multiplex delay measuring apparatus of the present embodiment has k
Sliding correlation detection is performed with a factor of "3000". As a result, the logarithmic compression output of the delay profile and the limiter output of the LOG amplifier for logarithmic compression are subjected to quadrature detection to output quadrature components normalized by amplitude.

The triangular wave shown in FIG. 6C is obtained as the correlation detection output, and the phase of the carrier during this period is constant. When the sliding correlation detection is performed with the k-factor “3000”, the actual delay amount is multiplied by 3000 and output. For example, 10 ns (nanosecond), which is an interval between one chip at a transmission speed of 100 Mbps, is 30 μS (microsecond).
Is output as The interval between the bottom surfaces of the triangular waves shown in FIG. 6C is 60 μs at the same transmission speed.
Further, a synchronization signal is output every time the 3001PN code sequence is transmitted.

The signal processing unit 104 converts the logarithmically compressed delay profile and the normalized quadrature signal output from the receiving unit 103 into digital data and stores them in a first to a first order.
Third A / D conversion boards 151 to 153, a display (DISP) 154 for display, a printer (PRT) 155 for printout, and a keyboard (KB) 156 for data input are connected. A workstation (WS) 157 is provided. I / O board 1
58 is an antenna element selection signal 15 required for TDM reception.
9, which is connected to the workstation 157 and the first to third A / D conversion boards 151 to 153.

First to third A / D conversion boards 151 to 1
The sampling frequency 53 is 8.5 MHz if 512 snapshots (512 sample data) are sampled in a section of a triangular wave having a width of 60 μs. In addition, the storage capacity for temporary storage is 1 Mbyte in consideration of TDM reception of 16 channels. An A / D conversion board having such a sampling frequency and storage capacity can be easily obtained. In addition, the sampling timing of the first to third A / D conversion boards 151 to 153 needs to be synchronized in order to estimate the angle of arrival. The I / O board 158 includes the receiving unit 1
The address of the antenna element for TDM reception is generated based on the synchronization signal of No. 03, and is notified to both the reception antenna unit 102 and the workstation 157. A signal for notifying the measurement dimension of the angle of arrival selected by the keyboard 156 is transmitted to the receiving antenna unit 102 via the I / O board 158.
Will be notified.

FIGS. 11 and 12 show the flow of processing of the radio wave environment analyzer of the present embodiment. When performing measurement using this apparatus, the measurer first sets the estimated dimension of the angle of arrival to “1” from the keyboard 156 shown in FIG.
The user may input “dimension” or “two-dimension.” Such input may be such as selectively pressing the numeric keypad “1” or “2” on the keyboard 156, or “1dimension” or “two-dimension”. The workstation 157 may analyze the input contents to determine whether the operator has selected one dimension or two dimensions (see FIG. 2). 11 Step S201).

One-dimensional arrival angle (horizontal angle or elevation angle)
Is selected (step S201;
Y) As the antenna element selection signal 159, a signal for selecting the linear array antenna 121 for estimating the one-dimensional arrival angle is received via the I / O board 158.
(Step S202). As a result, the linear array antenna 121 is selected. next,
The workstation 157 controls the first to third A / D conversion boards 151 to 153, and performs logarithmic compression of the delay profiles obtained by receiving the first to _sixteenth antenna elements 121 _{01 to} 121 ₁₆ respectively. The signal and the normalized orthogonal signal are digitized and stored in time series (steps S203, S204). The reception time of the first to sixteenth antenna elements 121 _{01 to} 121 ₁₆ coincides with the section in which a continuous PN code sequence of 3001 occurs, and the switching supplied to the first switch 123 from the interface circuit 126 is performed. The antenna elements 121 _{01 to} 121 ₁₆ are sequentially designated in synchronization with the signal 127, and data sampling is performed.

Next, the workstation 157 displays the logarithmically compressed delay profile on the display 154 (step S205). Delay profile is first
16th antenna elements 121 _{01 to} 121 in total
You can draw about each of the ₁₆ However, in this embodiment, there is a restriction on the screen of the display 154, and the receiving antenna element is selected and displayed.
The measurer can know the propagation delay time and the relative received power of the multipath wave from the displayed delay profile.

In this state, the workstation 157 monitors an input from the keyboard 156 (step S20).
6). This is set by the measurer inputting the propagation delay time of the signal wave whose arrival angle is to be estimated (Y), and when the parameter is set by further inputting the predetermined parameter (step S207), the work is performed. The station 157 extracts TDM reception data (step S
208). Here, the input of the predetermined parameter in step S207 means the algorithm used by the measurer,
This refers to input of parameters such as applicability of moving average and the number of snapshots. On this basis, the workstation 157 at step 208 is designated around a designated time for all of the antenna elements 121 _{01-121 16} of the first to third A / D conversion board 151 to 153 from 16 The logarithmic compressed signal and the normalized orthogonal signal of the delay profile of the number of snapshots are read out.

Next, the workstation 157 determines whether or not to perform a moving average (step S209). When performing the moving average (Y), the extracted received signal is multiplied by the inverse matrix of the inter-element coupling matrix, and the inter-element coupling component (Mutual Coupl) is calculated.
Unnecessary signal due to ing) is removed (step S210). When the moving average is not performed (step S209; N),
The processing in step S210 is not performed. When data of 16 channels (ch) for the first to sixteenth antenna elements 121 _{01 to} 121 ₁₆ is collected in this manner (step S211; Y), all of these antenna elements 121 _{01 to} 121 _{16 are} collected. Using a snapshot of
The covariance matrix is estimated (step S212). And
In the next step S213, it is determined which algorithm is specified, and the angle of arrival and relative power are estimated using the specified algorithm (step S21).
4-S216). However, the relative power is estimated only when the eigenvalue decomposition method is used. The estimation result is displayed on the display 154 (step S217).

FIG. 12 is a flowchart showing the operation of step S in FIG.
The processing when the two-dimensional arrival angle estimation is selected at 201 is shown. In this case, (Step S20
1; N), a signal for selecting the planar array antenna 122 for estimating the two-dimensional arrival angle is received via the I / O board 158 as the antenna element selection signal 159.
02 (Step S218). As a result, the planar array antenna 122 is selected. Thereafter, steps S203 to S212 in FIG.
(Steps S219 to S219)
S228). Thereafter, the arrival angle and the relative power are estimated by applying the two-dimensional-unitary Esprits method described above (step S229), and the estimation result is displayed on the display 154 (FIG. 11). Step S217).

First Modification of the Invention

FIG. 13 shows the configuration of a radio wave environment analyzer according to a first modification of the present invention. The radio wave environment analyzer includes a transmitting unit 101, a receiving antenna unit 102A,
It comprises a receiving unit 103 and a signal processing unit 104. The configuration other than the receiving antenna unit 102A is the same as that of the radio wave environment analyzer shown in FIG. This figure 1
In FIG. 3, the same portions as those in FIG. 10 are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

As a receiving antenna constituting the receiving antenna unit 102A, a linear array antenna 121 for estimating a one-dimensional angle of arrival is prepared. The antenna 121 includes 16 antenna elements 121 _{01 to} 121 ₁₆ . Changeover switch 1 from interface circuit 126
23, a switching signal 127 is supplied.
Thus, the sixteen antenna elements 121 _{01 to} 121 ₁₆ are cyclically selected one by one.
The reception output 131 of the antenna element is
A outputs. The TD from the I / O board 158 of the signal processing unit 104 to the interface circuit 126
An antenna element selection signal 159A required for M reception is input.

In the radio wave environment analyzer having such a configuration,
A simple analysis using only the linear array antenna 121 can be performed.

Second Modification of the Invention

FIG. 14 shows the configuration of a radio wave environment analyzer according to a second modification of the present invention. The radio wave environment analyzer includes a transmitting unit 101, a receiving antenna unit 102B,
It comprises a receiving unit 103 and a signal processing unit 104. The configuration other than the receiving antenna unit 102B is the same as that of the radio wave environment analyzer shown in FIG. This figure 1
In FIG. 4, the same portions as those in FIG. 10 are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

As a receiving antenna constituting the receiving antenna section 102B, a plane array antenna 122 for estimating a one-dimensional arrival angle is prepared. The planar array antenna 122 includes 16 antenna elements 122 _{01 to} 122 ₁₆ . A switching signal 128 is supplied from the interface circuit 126 to the changeover switch 123, whereby the 16 antenna elements 122 ₀₁ to 122 ₀₁ .
122 ₁₆ is adapted to be selected cyclically one by one. The reception output 131 of the antenna element is output from the reception antenna unit 102B. Note that the signal processing unit 104
I / O board 158 to interface circuit 126
Includes an antenna element selection signal 159 required for TDM reception.
B is input.

In the radio wave environment analyzer having such a configuration,
A simple analysis using only the planar array antenna 122 can be performed.

In the embodiments and the modified examples described above, data received by a plurality of antenna elements constituting an array antenna is selected in a time-division manner. However, a circuit for processing received data independently for each antenna element Is provided, and by combining the data for each antenna element, it is possible to simultaneously process the arrival direction, the propagation delay time, and the relative power of the incident signal with high accuracy. Since such processing uses a plurality of signal processing systems, the circuit configuration of the entire radio wave environment analyzer becomes complicated, and it is necessary to correct the processing results for each processing system. There is an advantage that it becomes possible to analyze.

In the embodiment, as shown in FIG. 9, the desired propagation delay time is designated on the display screen by moving the time cursor. It is also possible to select the propagation delay time by the above method. Further, in the embodiment, FIG.
Although a PDA gram as shown in FIG. 3F is created and displayed, the display method is not limited to this, and it is obvious that various display forms are possible.

Further, in the embodiment, the arrival direction, propagation delay time and relative power of the main wave and the multipath wave are estimated by partially using the ESPRIT method as one of the eigenvalue decomposition methods. Law is Unitar
Of course, the y ESPRIT method may be used.

In the present invention, the direction of arrival of the incident signal
Although the radio wave environment analyzer capable of simultaneously measuring the propagation delay time and the relative power has been described, FIG.
A communication system in which a mobile station selects a valid main wave and a multipath wave from radio waves transmitted from a base station using a PDA gram as shown in (1) to improve reception quality. Of course, it is also possible.

[0089]

As described above, claims 1 to 4 are described.
According to the described invention, the delay profile display means displays the delay profile of each antenna element, so that the delay time distribution of the incoming signal can be known.
Moreover, since the time for analyzing the direction of arrival is specified from these delay profiles, the direction of arrival, the propagation delay time, and the relative power of the incident signal to be analyzed can be quickly measured. In addition, since the direction of arrival, the propagation delay time, and the relative power can be measured simultaneously, the reliability of the result can be improved as compared with the conventional case where the measurement is performed individually. According to the first to fourth aspects of the present invention, since the arrival direction is determined based on the measurement of the delay profile using the correlation of the PN code, it is necessary to lay a cable between transmission and reception. Therefore, there is an effect that measurement can be freely performed in an outdoor mobile communication environment.

Further, according to the first and second aspects of the present invention, since the signal selecting means sequentially selects and extracts one signal from the array antenna received by the plurality of antenna elements, a circuit for subsequent signal processing is provided. The portion can be shared by each antenna element, and there is an effect that a correction circuit for correcting a difference in characteristics between these circuit portions is not required.

According to the second and fourth aspects of the present invention, there is provided a PDA gram display means for displaying a PDA gram as a graph showing the relative power, propagation delay time and arrival direction of a plurality of arriving signals. Therefore, there is an advantage that the relationship between the three can be grasped intuitively.

Further, according to the third and fourth aspects of the present invention, a circuit is provided which independently processes signals received by each of the antenna elements. The amount of data to be analyzed can be increased, and a high-speed and reliable processing result can be obtained.

According to the twelfth aspect of the present invention, ESPRIT is used as a method of eigenvalue decomposition for determining the arrival direction, propagation delay time and relative power of the main wave and the multipath wave.
Since the estimation is performed using the method, there is an effect that the spectrum search of the MUSIC method becomes unnecessary.

Further, the invention according to claim 13 has a plurality of algorithms for calculating the direction of arrival,
Since the signal processing means includes an algorithm selecting means for selecting any one of the algorithms, there is an advantage that various algorithms can be selected according to the purpose of analysis.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a radio wave environment analyzer according to an embodiment of the present invention.

FIG. 2 is a diagram showing various waveforms for explaining BPSK modulation.

FIG. 3 is various waveform diagrams illustrating the operation principle of delay profile measurement.

FIG. 4 is an explanatory diagram showing a state of a filter output at the time of synchronization.

FIG. 5 is an explanatory diagram showing a state of a filter output at the time of asynchronous operation.

FIG. 6 is an explanatory diagram showing a PN encoded sequence and a sliding correlation output of a transmitting device and a receiving device.

FIG. 7 is an explanatory diagram showing a principle of measuring an angle of arrival.

FIG. 8 is an explanatory diagram showing a state of a PN synchronization pulse and received data.

FIG. 9 is an explanatory diagram showing a relationship between a delay profile based on each received data, an estimation of an angle of arrival, and a PDA gram.

FIG. 10 is a block diagram illustrating a configuration of a radio wave environment analyzer according to an embodiment of the present invention.

FIG. 11 is a flowchart showing a case where the arrival angle in the processing flow of the radio wave environment analyzer of the present embodiment is one-dimensional.

FIG. 12 is a flowchart showing a case where the angle of arrival is not one-dimensional in the processing flow of the radio wave environment analyzer of the present embodiment.

FIG. 13 is a block diagram illustrating a configuration of a radio wave environment analyzer according to a first modification of the present invention.

FIG. 14 is a block diagram illustrating a configuration of a radio wave environment analyzer according to a second modification of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 11 transmitting device (transmitting means) 12 receiving device (receiving means) 13 signal processing device (signal processing means) 27, 115 transmitting antenna 31 antenna element 32 array antenna 39 first multiplier 41 PN code generator 46 second multiplication Device 47 signal generator 53 logarithmic amplifier (LOG) 55 quadrature detector 61 CPU 66 main storage device (MEM) 69 input / output device 101 transmitting unit 102, 102A, 102B receiving antenna unit 103, 141 receiving unit 104 signal processing unit 121 straight line Array antenna 122 Planar array antenna 126 Interface circuit 154 Display (DISP) 155 Printer (PRT) 157 Workstation (WS)

Claims (13)

[Claims] A transmitting means for radiating a transmission signal subjected to two-phase shift keying with a PN code sequence from a transmitting antenna; an array antenna for receiving a transmission signal transmitted by the transmitting means with a plurality of antenna elements; Signal selection means for selecting and extracting one signal from the array antenna; and inversely taking the product of the signal selected by the signal selection means and a signal having the same code sequence as the transmission signal and having a slightly different transmission speed. Receiving means comprising: despreading means for spreading, and quadrature detection means for converting a signal despread by the despreading means into an intermediate frequency or baseband signal, quadrature detection and outputting as a quadrature detection signal, A switching signal supply means for supplying a switching signal for selecting a signal to the means; and Storage means for digitizing and storing the quadrature detection signal, and a delay for displaying a delay profile representing the relationship between the power and the delay time of the quadrature detection signal obtained by reception by a predetermined antenna element in the array antenna Profile display means; time designating means for designating a time for analyzing the direction of arrival from the delay profile displayed on the delay profile display means; and time designation from the digitized quadrature detection signals stored in the storage means. Extracting means for extracting a signal at a time designated by the means, and signal processing means comprising arrival direction calculating means for estimating a covariance matrix of a reception signal of the array antenna at the designated time to obtain an arrival direction. A radio wave environment analyzer comprising: 2. A transmitting means for radiating a transmission signal subjected to two-phase shift keying with a PN code sequence from a transmitting antenna, an array antenna for receiving a transmission signal transmitted by the transmitting means with a plurality of antenna elements, Signal selection means for selecting and extracting one signal from the array antenna; and inversely taking the product of the signal selected by the signal selection means and a signal having the same code sequence as the transmission signal and having a slightly different transmission speed. Receiving means comprising: despreading means for spreading, and quadrature detection means for converting a signal despread by the despreading means into an intermediate frequency or baseband signal, quadrature detection and outputting as a quadrature detection signal, A switching signal supply means for supplying a switching signal for selecting a signal to the means; and Storage means for digitizing and storing the quadrature detection signal, and a delay for displaying a delay profile representing the relationship between the power and the delay time of the quadrature detection signal obtained by reception by a predetermined antenna element in the array antenna Profile display means; time designating means for designating a time for analyzing the direction of arrival from the delay profile displayed on the delay profile display means; and time designation from the digitized quadrature detection signals stored in the storage means. Extracting means for extracting a signal at a time designated by the means, arrival direction calculating means for estimating a covariance matrix of a received signal of the array antenna at the designated time to determine an arrival direction, and relative power of a plurality of incoming signals. PDA gram display means for displaying a PDA gram as a graph showing the propagation delay time and the direction of arrival; Radio environment analysis apparatus characterized by comprising a signal processing means having. 3. A transmitting means for radiating a transmission signal subjected to two-phase shift keying with a PN code sequence from a transmitting antenna, an array antenna for receiving a transmitting signal transmitted by the transmitting means with a plurality of antenna elements, Despreading means for individually despreading a product of a signal received by each of the plurality of antenna elements of the array antenna and a signal having a slightly different transmission rate in the same code sequence as the transmission signal, and despreading means. A receiving unit comprising: a quadrature detection unit that converts each despread signal into an intermediate frequency or baseband signal, performs quadrature detection and outputs a quadrature detection signal corresponding to each antenna element, and outputs the quadrature detection signal from the quadrature detection unit. Storage means for digitizing and storing a plurality of orthogonal detection signals corresponding to each of the antenna elements obtained, Delay profile display means for displaying a delay profile representing the relationship between the power of the quadrature detection signal and the delay time, and time designating means for designating the time for analyzing the direction of arrival from the delay profile displayed on the delay profile display means. Extracting means for extracting a signal at a time designated by the time designating means from the digitized quadrature detection signals stored in the storage means, and a covariance matrix of a reception signal of the array antenna at the designated time. A radio wave environment analyzer comprising: a signal processing unit including an arrival direction calculation unit for estimating an arrival direction. 4. A transmitting means for radiating a transmission signal subjected to two-phase shift keying with a PN code sequence from a transmitting antenna, an array antenna for receiving a transmitting signal transmitted by the transmitting means with a plurality of antenna elements, Despreading means for individually despreading a product of a signal received by each of the plurality of antenna elements of the array antenna and a signal having a slightly different transmission rate in the same code sequence as the transmission signal, and despreading means. A receiving unit comprising: a quadrature detection unit that converts each despread signal into an intermediate frequency or baseband signal, performs quadrature detection and outputs a quadrature detection signal corresponding to each antenna element, and outputs the quadrature detection signal from the quadrature detection unit. Storage means for digitizing and storing a plurality of orthogonal detection signals corresponding to each of the antenna elements obtained, Delay profile display means for displaying a delay profile representing the relationship between the power of the quadrature detection signal and the delay time, and time designating means for designating the time for analyzing the direction of arrival from the delay profile displayed on the delay profile display means. Extracting means for extracting a signal at a time specified by the time specifying means from the digitized quadrature detection signal stored in the storage means, and a covariance matrix of a reception signal of the array antenna at the specified time. Signal processing means comprising: a direction of arrival calculating means for estimating a direction of arrival; and a PDA gram display means for displaying a PDA gram as a graph showing relative power, propagation delay time and direction of arrival of a plurality of arriving signals. A radio wave environment analyzer comprising: 5. An array antenna of the receiving means, wherein a plurality of antenna elements are arranged on a straight line, and the signal processing means estimates a horizontal angle or an elevation angle. The radio wave environment analyzer according to claim 1. 6. An array antenna of the receiving means, wherein a plurality of antenna elements are arranged in a matrix on a plane, and the signal processing means estimates a horizontal angle and an elevation angle. Claim 1 to Claim 4
Radio wave environment analyzer as described. 7. The array antenna of the receiving means includes a linear array antenna in which a plurality of antenna elements are arranged in a straight line, and a planar array antenna in which a plurality of antenna elements are arranged in a matrix on a plane. The radio wave environment analyzer according to claim 1, wherein: 8. The array antenna of the receiving means includes a linear array antenna in which a plurality of antenna elements are arranged in a straight line, and a planar array antenna in which a plurality of antenna elements are arranged in a matrix on a plane. 8. The radio wave environment analyzer according to claim 7, wherein said signal processing means comprises an array antenna selecting means for selecting one of the array antennas. 9. The apparatus according to claim 1, wherein said direction-of-arrival calculating means estimates the direction of arrival by an eigenvalue decomposition method.
The radio wave environment analyzer according to claim 4. 10. The radio wave environment analyzer according to claim 1, wherein said direction of arrival calculating means estimates the direction of arrival based on the principle of an interferometer. 11. An arrival direction of a main wave and a multipath wave,
The radio wave environment analyzer according to claim 9, wherein the propagation delay time and the relative power are estimated by using the MUSIC method as one of the eigenvalue decomposition methods. 12. The arrival direction of a main wave and a multipath wave,
The radio wave environment analyzer according to claim 9, wherein the propagation delay time and the relative power are estimated by using the ESPRIT method as one of the eigenvalue decomposition methods. 13. The arrival direction calculation means has a plurality of algorithms for calculating the direction of arrival, and the signal processing means has an algorithm selection means for selecting any one of the algorithms. The radio wave environment analyzer according to claim 1, wherein: