JP2630889B2 - Radio propagation delay measurement equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio wave propagation path delay measuring device in mobile communication, and more particularly to a radio wave (R) to be measured.
F) The present invention relates to a radio wave propagation path measuring apparatus which makes a transmission band of a frequency band narrower equivalently and improves measurement accuracy of delay distortion which causes transmission quality deterioration.

[0002]

2. Description of the Related Art In recent mobile communications, remarkable improvements have been made, such as the digitization of the modulation system and the increase in transmission speed. However, in this type of communication system, there has conventionally been a problem of deterioration of transmission characteristics due to multiple propagation paths. For this reason, it is necessary to precisely measure the delay profile of a propagation path that causes delay distortion as a cause of deterioration and remove the cause. At this time, the transmission bandwidth must be very wide in order to increase the measurement accuracy of the delay profile, and such high-precision measurement is not possible in view of radio wave interference accompanying an increase in traffic in the future. And need some action.

[0003]

By the way, in the conventional measurement of the radio wave propagation path, a coded signal excellent in detecting the autocorrelation characteristic of the signal is used to transmit the coded signal on the transmission side via the propagation path. Cross-correlate with the coded signal received
The delay profile of the propagation path was measured. In that case,
The measurement accuracy is limited by the chip rate, that is, the measurement accuracy is given by approximately 1 / T where T is the chip rate. For example, to obtain a measurement accuracy of 10 μsec, 10
A chip rate of 0 Mbps, that is, a transmission band of the RF band, has a problem that a bandwidth of about 300 MHz is required and a very wide transmission band is required. In view of the above-mentioned problems of the prior art, the present invention is to improve the accuracy of measurement of delay distortion, which is a cause of deterioration of transmission quality, by narrowing the transmission band of the RF frequency band required for measurement to an equivalent narrow band. It is an object of the present invention to provide a path delay measuring device.

[0004]

In order to achieve the above object, a radio wave propagation path delay measuring apparatus according to the present invention, on the transmitting side, divides a frequency band of an encoded data signal to be transmitted into a narrow band by dividing it into a staggered frequency band. Narrowing means for converting, and a base signal generating means for generating a plurality of base signals obtained by shifting a center frequency of the plurality of band-limited narrow band signals to a predetermined common frequency, and a carrier wave based on these base signals. Transmitting means for sequentially and periodically transmitting the obtained modulated carrier to the receiving side via the multiplex propagation path, while the receiving side receives a transmission signal sequentially transmitted from the transmitting side. Receiving means for demodulating and demodulating the signal, periodic signal extracting means for extracting a periodic signal from the demodulated signal, and shifting the frequency of the demodulated base signal in a direction opposite to that on the transmitting side by the extracted periodic signal. Reverse shift means for obtaining a signal spectrum, in which taking a cross-correlation between the encoded data signal obtained transmission signal spectrum and the transmission side and a correlation means to be subjected to determination of the delay profile.

[0005]

The transmission coded signal is converted into a plurality of narrowband signals by the narrowing means on the transmitting side, and the base signal generating means shifts these narrowband signals to one predetermined frequency,
The transmitting means sequentially transmits the coded signals narrowed in this way to the receiving side. On the receiving side, a periodic signal is extracted by the periodic signal extracting means from the transmission signal received by the receiving means, and the base signal is converted into a demodulated transmission signal based on the periodic signal by the inverse shift means to obtain the signal spectrum of the original coded data signal. And further, a cross-correlation between the propagated signal returned to the original signal spectrum by the correlation means and the encoded data signal on the transmitting side is taken, whereby the delay profile of the radio wave propagation path is determined. Become. Therefore, the delay profile can be measured with high accuracy without using a wide-band signal transmission path unlike the related art.

[0006]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of a radio propagation delay measuring apparatus according to the present invention. FIGS. 1 and 2 are block diagrams respectively illustrating the configuration of the transmission side and the reception side of the radio wave propagation path delay measuring apparatus according to the present invention. In FIG. 1, reference numeral 1 denotes an encoded signal generation circuit that generates an encoded data signal that is a transmission signal on a transmission side;
Reference numeral 2 denotes an N-stagger narrowband filter that divides the generated coded data signal into a plurality of (N) staggered narrowband signals on the frequency axis. Reference numeral 3 denotes a common frequency of these narrowband signals. A base frequency conversion circuit for generating a plurality of base signals by shifting the base signals to a predetermined frequency, which is controlled by a frame period signal generation circuit to be described later, for sequentially switching the base signals and transmitting the base signals in time series; The circuit 5 is an RF band modulation circuit for transmitting the transmitted base signal on a carrier wave, and the reference numeral 6 generates a fixed frame period signal, thereby controlling the coded signal generation circuit 1 and the base frequency switching circuit 4. This is a frame period signal generation circuit.

Further, in FIG. 2, reference numeral 7 denotes a reception side which receives a transmission signal transmitted from a transmission side via a radio wave propagation path, and converts the reception signal to an intermediate frequency by a local oscillation signal from a local oscillation circuit described later. (IF) down-converter 8 for converting the intermediate frequency signal into an IF signal
A narrow band filter, 9 is a frame detection circuit for extracting a frame period signal from the intermediate frequency signal from the IF narrow band filter 8, 10 is a demodulation circuit for demodulating the intermediate frequency signal, 1
Reference numeral 1 denotes an IF oscillation circuit that supplies an intermediate frequency signal for demodulation to the demodulation circuit 10. Reference numeral 12 temporarily stores the demodulated base signal. Storage circuit for repeatedly outputting, 1
Reference numeral 3 denotes a frequency conversion circuit for combining the base signal sequentially output from the storage circuit 12 with the original encoded data signal. A cross-correlation circuit 15 that obtains a correlation and obtains a delay profile of the radio wave propagation path, and a local oscillation circuit 15 that supplies a local oscillation signal to the down converter 7. It should be noted that the N sub-band narrow band filter has, for example, a bandwidth of 100 MHz necessary for transmitting a code pattern satisfactorily.
Then, in the case of N = 100 division, the code pattern is divided at intervals of 1 MHz.

In the embodiment of the present invention configured as described above, first, on the transmitting side, the encoded signal generating circuit 1 is generated from the frame synchronizing signal generating circuit 6 generated from the frame synchronizing signal generating circuit 6. A code pattern that provides good autocorrelation characteristics is periodically and repeatedly generated in synchronization with the generated frame synchronization signal. These code patterns are sent to an N-staggered narrow-band filter 2, where the bandwidth is divided into N and the signal is divided into N narrow-band signals. The divided narrow-band signals are input to the base frequency conversion circuit 3, where N (for example, 100) narrow-band signals have their center frequencies set to one predetermined common frequency (for example, 200 KHz).
１．２1.2 MHz) and converted into N base signals. Next, these N base signals are sent to the base frequency switching circuit 4, where the base signals divided into N (for example, 100) are sequentially switched according to the synchronization signal from the frame synchronization signal generation circuit 6 to perform RF band modulation. The RF signal is transmitted to the circuit 5, and the carrier is modulated by the base signal transmitted in the RF band modulation circuit 5, and the modulated carrier is transmitted to the receiving side as a transmission signal.

On the other hand, on the reception side, the transmission signal from the transmission side is mixed with the local oscillation signal from the local oscillation circuit 15 by the down converter 7 and converted into an intermediate frequency band (IF) signal. After the noise is removed by 8, the demodulation circuit 10 mixes with the intermediate frequency signal from the IF oscillation circuit 11, and the base signal from the transmission side is demodulated. On the other hand, the IF signal from which noise has been removed by the IF narrow band filter 8 is detected by the frame detection circuit 9 as a frame synchronization signal and a multi-frame synchronization signal inserted on the transmission side. This can be easily implemented, for example, by making the RF band power non-power between frames and changing the length. The base signal from the demodulation circuit 10 is temporarily stored in the storage circuit 12 and then repeatedly output in multi-frame units according to the frame signal from the frame detection circuit 9. These output base signals are synthesized by the frequency conversion circuit 13 into the original coded signal. The cross-correlation circuit 14 cross-correlates the synthesized signal with the code pattern on the transmission side, and thereby determines the delay profile of the radio wave propagation path.

In the above embodiment, the narrowing means and the base signal generating means on the transmitting side are provided as hardware, but the narrowband signal and the base signal obtained therefrom may be obtained by calculation. The same effect can be obtained by temporarily storing the calculation result in the storage means and extracting it as needed.

[0011]

As described above, according to the present invention, at the time of measuring the delay profile of the radio wave propagation path, on the transmission side,
The frequency band of the coded signal is divided into narrow bands, the center frequency of the divided narrow band signal is shifted to a specific frequency to form a base signal, and these base signals are sequentially transmitted on a carrier wave and transmitted. By converting the signal after propagation into the original coded signal and cross-correlating these signals with the first coded signal, the delay profile of the radio wave propagation path can be measured with high accuracy.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a circuit configuration on a transmitting side according to an embodiment of a radio propagation path delay measuring apparatus according to the present invention.

FIG. 2 is a block diagram showing a circuit configuration on the receiving side in the same manner.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Encoding signal generation circuit 2 N staggered narrow band filter 3 Base frequency conversion circuit 4 Base frequency switching circuit 5 RF band modulation circuit 6 Frame synchronization signal oscillation circuit 7 Down converter 8 IF narrow band filter 9 Frame detection circuit 10 Demodulation circuit 11 IF Internal oscillation circuit 12 Storage circuit 13 Frequency conversion circuit 14 Cross-correlation circuit

Claims (2)

(57) [Claims] In a radio wave propagation path delay measuring apparatus for measuring a delay distortion generated when a modulated carrier propagates from a transmitting side in a multiplex propagation path in mobile communication, the transmitting side staggers a frequency band of an encoded signal to be transmitted. Band narrowing means for dividing into a plurality of narrow bands in a manner, and a base signal generating means for generating a plurality of base signals obtained by shifting the center frequency of the band-limited narrow band signals to a predetermined common frequency. Transmitting means for modulating a carrier with these base signals, and sequentially and periodically transmitting the obtained modulated carrier to the receiving side via the multiplex transmission path, wherein the receiving side is sequentially from the transmitting side. Receiving means for receiving and demodulating the transmitted transmission signal, synchronizing signal extracting means for extracting a periodic signal from the demodulated signal, and transmitting the frequency of the base signal demodulated by the extracted synchronizing signal to the transmitting side. An inverse shift means for shifting the signal spectrum in the opposite direction to obtain an original signal spectrum; and a correlation means for determining a cross-correlation between the obtained signal spectrum and the encoded data signal on the signal side to determine a delay profile. A radio wave propagation path delay measuring device, characterized in that: 2. The method according to claim 1, wherein the narrow-band signal and the base signal obtained by the band-narrowing means and the base signal generating means on the transmission side are obtained by calculation, and the results are temporarily stored and used as needed. The radio wave propagation path delay measuring device according to claim 1.