JP3260225B2 - Wireless transmission signal level setting method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a wireless transmission signal level setting method for controlling a transmission signal level based on an N ratio.

[0002]

2. Description of the Related Art A radio transmission signal level setting method in a conventional frequency modulation type radio telephone apparatus will be described with reference to the drawings. FIG. 4 is a block diagram showing the configuration of a conventional frequency-modulated wireless telephone apparatus employing a wireless transmission signal level setting method. Reference numeral 1 denotes a slave unit of a frequency-modulation type wireless telephone device, and 2 denotes a slave unit composed of a microprocessor or the like.
Means for controlling main channel control and control of control channel data (hereinafter referred to as Cch data) for performing calling / incoming processing between a slave unit and a master unit, and 3 includes a microphone, a speaker, and the like, and includes a voice band signal. A voice interface means for converting the frequency band into a signal and adjusting an input / output gain; a transmission processing means for frequency-modulating (hereinafter, referred to as FM) the voice band signal, and a frequency shift modulation (hereinafter, referred to as FSK) for the Cch data; 5 is a reception processing means for demodulating the received FM signal and FSK signal, 15 is an up-conversion means for up-converting the modulated signal, 16 is a down-conversion means for down-converting the received signal, and 6 is an amplifying radio frequency band signal to be transmitted. Transmission power amplifying means, a receiving power amplifying means for amplifying a received radio frequency band signal, and 8 a radio wave signal between the slave unit and the master unit. Receiving an antenna to perform.

Reference numeral 9 denotes a discretizing means for sampling and quantizing the received signal at a fixed time, and 10 a received signal level calculating means for obtaining an average value of the received signal level from the data sampled and quantized by the discretizing means 9. Reference numeral 12 denotes a no-signal noise level storage means for storing previously measured / calculated no-signal noise level data. Reference numeral 12 denotes a reception signal level obtained from the reception signal level calculation means 10 and a no-signal noise level storage means. A pseudo S / N ratio calculating means 13 for obtaining a pseudo S / N ratio from a no-signal noise level stored in
Transmission signal level setting means 14 for determining a transmission signal level from the N ratio is a master unit of the frequency modulation type wireless telephone device.

[0004] The operation of the conventional frequency-modulated wireless telephone apparatus employing the conventional wireless transmission signal level setting method configured as described above will be described below. First, a transmission processing operation from the child device 1 to the parent device 14 will be described. The voice is subjected to voice band signal conversion and gain adjustment by the voice interface unit 3, modulated by the FM processing by the transmission processing unit 4, and up-converted to a radio frequency band signal by the up-conversion unit 15. The up-converted audio signal is power-amplified by the transmission power amplifying unit 6, and the amplified audio signal is transmitted to the base unit 14 as a transmission radio wave via the antenna 8. Further, the transmission processing unit 4 also transmits Cch data such as a calling process output from the control unit 2 to the FS.
The signal is modulated by the K method, is up-converted into a radio frequency band signal by an up-conversion unit 15, is power-amplified by a transmission power amplifying unit 6, and is transmitted as a transmission radio wave to the master unit 14 via an antenna 8.

Next, a description will be given of a reception processing operation and a wireless transmission signal level setting method when the slave unit 1 receives wireless data from the master unit 14. A signal transmitted as a transmission radio wave of a radio frequency band signal from base unit 14 is received by antenna 8 of handset 1. The received signal is amplified by the reception power amplification means 7, down-converted by the down-conversion means 16, demodulated by the reception processing means 5, audio data is output to the outside as audio by the audio interface means 3, and Cch data is controlled. It is processed by means 2. At this time, the Cch data received by the antenna 8 is input to the discretization unit 9 after passing through the reception power amplification unit 7 and the down-conversion unit 16 simultaneously with the above-described processing.
The FSK signal of the Cch data input to the discretization means 9 is sampled and quantized here. The received signal level calculation means 10 obtains the effective value of the received signal level in a certain section based on the sampled and quantized data (see FIG. 5). At this time, as shown in FIG. 5, when the sampling interval is a fixed time from t1 to t2 and the data of the received FSK signal is g '(t), the received signal level is expressed by the following equation (1). Become like

[0006]

(Equation 1)

The pseudo S / N ratio calculating means 12 is based on the received signal level obtained by the received signal level calculating means 10 and the no-signal noise level stored in the no-signal noise level storage means 11 in advance. A pseudo S / N ratio {S / N = (original signal + noise level with signal) / noise level with no signal} is calculated. The pseudo S / N obtained by the pseudo S / N ratio calculating means 12
Based on the result of N, the transmission signal level setting means 13 determines an appropriate transmission signal level and notifies the control means 2 of that. The control means 2 having received the notification keeps the S / N ratio constant by transmitting Cch data for adjusting the amplification factor of the transmission signal level to the base unit 14.

[0008]

However, in the above-mentioned conventional radio transmission signal level setting method, the S / N ratio is calculated in a pseudo manner (received signal level / noise level at the time of no signal). Since the transmission signal level is controlled according to the result, in the case of a received signal containing various actual noise components, the original signal level and the noise level when there is no signal do not change, When the noise level rises, it is erroneously recognized that the reception signal level has risen, and the transmission signal level has fallen. As a result, there has been a problem that a communication error increases in communication between the master unit and the slave unit.

The present invention solves the above-mentioned problems, and the
The N ratio is calculated by (original signal level / noise level at the time of signal presence), the true S / N ratio is obtained, and the optimum level control of the transmission signal is realized on-line. It is an object of the present invention to provide a wireless transmission signal level setting method capable of enabling communication and avoiding erroneous setting of a transmission signal level due to erroneous recognition of a reception signal level.

[0010]

According to the present invention, in order to achieve the above object, discretizing means for sampling and quantizing a received FSK signal at a fixed time in both a slave unit and a base unit of a radio telephone apparatus. Power spectrum calculating means for calculating the power spectrum of the received signal in the data window based on the received FSK signal in the data window which is time-shifted by one sampling time with one symbol length of the FSK signal only for two oscillation frequencies; An oscillating frequency detecting means for detecting an oscillating frequency from the maximum power spectrum calculated by the power spectrum calculating means, and an oscillating frequency estimating the original signal as a function from the received signal data based on the oscillating frequency detected from the oscillating frequency detecting means. Signal estimating means, received signal data and the original signal estimating means Noise component analysis means for analyzing the noise component of the received signal data by calculating the difference from the original signal estimated by the above, and a true signal / noise ratio between the original signal level and the level of the noise component when the signal is present. An S / N ratio calculating means and a transmission signal level setting means for setting a transmission signal level based on a result of the true S / N ratio calculating means are provided.

[0011]

With the above arrangement, the discretizing means receives the F
The SK signal is sampled and quantized, the power spectrum calculation means calculates a power spectrum of two oscillation frequencies from the received signal, and the oscillation frequency detection means detects the oscillation frequency from the power spectrum. The original signal estimating means estimates the original signal based on the oscillation frequency, and the noise component at signal presence analysis means analyzes the noise component of the received signal data by taking the difference between the received signal data and the original signal. Then, the true S / N calculating means finds the S / N ratio between the original signal level and the noise component level at the time of the signal, and notifies the transmission signal level setting means of the result. The transmission signal level is sequentially controlled so that the ratio becomes constant.

[0012]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a wireless transmission signal level setting method according to one embodiment of the present invention. Reference numeral 21 denotes a slave unit of a frequency-modulation wireless telephone device;
Is a control means for controlling the main channel of the slave unit 21 and for controlling the Cch data for performing the calling / incoming process between the slave unit and the master unit, and 23 is a voice band constituted by a microphone, a speaker, and the like. Audio interface means 24 for converting to signal and adjusting input / output gain, modulates audio band signal by FM system, and converts Cch data to FSK.
Transmission processing means for modulating the received signal by the system, 25: reception processing means for demodulating the received FM signal and FSK signal, 26: up-conversion means for up-conversion, 27: down-conversion means for down-conversion, 28: radio frequency band signal to be transmitted Transmission power amplifying means for amplifying
Is a received power amplifying means for amplifying the received wireless band signal,
Reference numeral 30 denotes an antenna for transmitting and receiving radio waves between the slave unit and the master unit.

Reference numeral 31 denotes a discretizing means for sampling and quantizing a received signal at a fixed time, and 32 denotes a data based on a received FSK signal in a data window which is time-shifted by one symbol length of the FSK signal every sampling time. Power spectrum calculating means for calculating the power spectrum of the received signal in the window only for two oscillation frequencies; 33, an oscillation frequency detecting means for detecting an oscillation frequency from the power spectrum calculated by the power spectrum calculating means 32; An original signal estimating means for estimating the original signal as a function from the received signal data on the basis of the oscillation frequency detected in the step (a); and 35, the difference between the received signal data and the original signal estimated by the original signal estimating means. Noise component analysis means at the time of a signal to analyze the noise component of 6 finds the S / N ratio of the original signal level and the signal present at the noise component level of the true S / N ratio calculating means,
37 is a transmission signal level setting means for setting the level of the transmission signal based on the result of the true S / N ratio calculation means 36, and 38 is a base unit of the frequency modulation type wireless telephone device.

The operation of the conventional frequency-modulated wireless telephone apparatus employing the conventional wireless transmission signal level setting method configured as described above will be described below with reference to FIGS. 1, 2 and 3. FIG. FIG. 2 is a view for explaining the FSK signal received by the power spectrum calculation means 32 of FIG. 1 and a data window at each sampling time.
FIG. 3 is a diagram showing a relationship between a power spectrum near an oscillation frequency and a data window in the power spectrum calculation means 32 of FIG.

In the radio telephone apparatus of the frequency modulation system according to the present embodiment, the operation of transmission processing from the slave unit 21 to the master unit 38 is exactly the same as that of the conventional example, and a description thereof will be omitted.

Next, a case where the handset 21 receives a radio signal from the base unit 38 and performs a processing operation will be described. Base unit 3
The radio signal transmitted as the transmission radio wave of the radio frequency band signal is received by the antenna 30 of the slave unit 21, the received signal is amplified by the reception power amplifying means 29, down-converted by the down-conversion means 27, and then received. Means 2
5 demodulated. Here, the audio signal is output to the outside via the audio interface means 23 and the Cch
The data is processed by the control means 22.

At the same time as the processing described above, the Cch data is down-converted by the down-converting means 27 and then input to the discretizing means 31. The FSK signal in the Cch data is sampled and quantized by the discretizing means 31. Power spectrum calculation means 32
Calculates the power spectrum of the received signal in a data window of one symbol length only for two oscillation frequencies based on the sampled and quantized data of the Cch signal.

Here, the operation of the power spectrum calculation means 32 is described.
Information symbol changes from "1" to "0" for work
This will be described with reference to FIGS. However
Fc in FIG. 2 is the carrier frequency, f₁ Is an information symbol
The oscillation frequency for "1", f ₀ Is an information symbol
Oscillation frequency for 0 ", Δf is carrier frequency f_c From
Is the frequency shift of That is, f₀ = F_c −Δf, f₁ 
= F_c + Δf. Is the current sampling
Im K at K = 0, N / 4, N / 2, 3N / 4, N
The rightmost of each data window
Is the current sampling time K. Data Win
The dough width is one symbol length, and the sump in one symbol is
Let N be the number of files. Also, K_c Is the center of the data window
Time at, K_L Is the oldest in the data window
Time. This power spectrum is calculated using specs
The maximum entropy is very high
-Method (MEM) is applied. FIG.
3 in 3 corresponds to one-to-one.

FIG. 2 (current sampling time K = 0)
When the power spectrum is obtained from the sampling data in the data window of
Since the zero frequency component is not included, it has a high power spectrum only when f ₁ as shown in FIG. Actually, since f ₀ and f ₁ are known frequencies, the power spectrum calculating means 32 does not need to obtain a power spectrum in a wide frequency range, but only needs to obtain f ₀ and f ₁ . Further, targeting only the oscillation frequency itself has a function similar to that of the narrow-band bandpass filter. Figure 3, respectively the power spectrum of the f0 and f ₁ in the PS ₀ and (f ₀₎ When PS ₀ (f _1), when the of FIG 3, it can be seen that the dominant frequency is the oscillation frequency f _1. From this oscillation frequency with respect to time K = -N / 2 of the central data window of the current sampling time K = 0 becomes "f _1".

The same processing is performed for the FSK signal shown in FIG.
Repeated at each sampling time, in the case of the data window of FIG. 2, the power spectrum becomes as shown in FIG. 3, respectively. As in the case of FIG. When the oscillation frequency for the center time is determined, FIG.
An oscillation frequency analysis result like the following is obtained.

The relationship between the power spectrum and the oscillation frequency is as shown in (Table 1). Oscillation frequency detection means 3
3 is FS from the result of the power spectrum calculation means 32.
The frequency of the K signal is detected.

[0022]

[Table 1]

Next, the original signal is converted into a function ｛g (t) = A sin
(2πfit + θ)｝, the original signal estimating means 3
4 obtains the parameters A and θ using the least square method of the following equation (2) based on the results of the power spectrum calculation means 32 and the oscillation frequency detection means 33, and converts the original signal into a function g
(T). However, the received signal is an FSK signal. Here, g (t) is an estimation function of the original signal, A is amplitude, π is pi, fi is oscillation frequency (i = 0, 1), θ
Is the phase and g '(t) is the actual data value of the received signal.

[0024]

(Equation 2)

G (t) obtained by the original signal estimating means 34
On the basis of the above, the noise component analyzing means 35 with the signal has the noise component ｛n
(T) = g ′ (t) −g (t)} is analyzed. Then true S
The / N ratio calculating means 36 calculates the true S / N ratio from the following equation (3), that is, {true S / N = original signal level / noise level at the time of signal presence} to obtain an appropriate S / N ratio. Calculate.

[0026]

(Equation 3)

The transmission signal level setting means 37 calculates the correction signal level ｛Δg _L based on the result of the true S / N ratio calculating means 36.
= (True S / N ratio-reference S / N ratio) × noise level with signal｝ is obtained, and the optimal transmission signal level ｛g ′ _L = g _L −Δg
_L } is updated, and the control unit 22 is notified of the update.
Here, the reference S / N ratio is a preset S / N ratio for the control purpose, and g _L is the optimum transmission signal level before updating, that is, the estimated source obtained by the true S / N ratio calculating means 36. The signal level. The control unit 22 that has received the notification sequentially transmits the optimal transmission signal level data to the parent device using the Cch data, whereby the optimal level control of the transmission signal of the parent device can be realized online.

In this embodiment, the case where the wireless transmission signal level setting method is adopted for the slave unit has been described. It goes without saying that the above operation is performed.

[0029]

As described above, according to the present invention, the S / N
Is calculated as {original signal level / noise level with signal} instead of {(original signal level + noise level with signal) / noise level with no signal}, and the optimal level control of the transmission signal is sequentially performed online. Therefore, highly reliable wireless communication with less communication errors can be performed, and erroneous setting of the transmission signal level due to erroneous recognition of the reception signal level can be avoided.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a frequency-modulation wireless telephone apparatus employing a wireless transmission signal level setting method according to an embodiment of the present invention.

FIG. 2 is a view for explaining an FSK signal received by a power spectrum calculation means 32 and a data window at each sampling time in the frequency modulation wireless telephone device of FIG.

FIG. 3 is a view showing a relationship between a power spectrum and a data window in the vicinity of an oscillation frequency in a power spectrum calculating means 32 in the frequency modulation wireless telephone device of FIG. 1;

FIG. 4 is a configuration diagram of a conventional frequency-modulation wireless telephone apparatus that employs a wireless transmission signal level setting method.

FIG. 5 is a view for explaining a method of calculating the level of an FSK signal received by the received signal level calculating means 10 in the conventional frequency-modulation wireless telephone apparatus of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 21 Frequency modulation wireless telephone handset 22 Control means 23 Voice interface means 24 Transmission processing means 25 Reception processing means 26 Up-conversion means 27 Down-conversion means 28 Transmission power amplification means 29 Reception power amplification means 30 Antenna 31 Discretization means 32 Power spectrum Calculation means 33 Oscillation frequency detection means 34 Original signal estimation means 35 Noise component analysis means with signal 36 True S / N ratio calculation means 37 Transmission signal level setting means 38 Frequency modulation wireless telephone base unit

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04B ^7/ 24-7/26 102 H04Q ^7/ 00-7/38

Claims (1)

(57) [Claims] 1. A wireless transmission signal level setting method for a wireless telephone device comprising a pair of a master unit and a slave unit and performing wireless communication by the FSK method between the master unit and the slave unit. A discretizing means for sampling and quantizing the received FSK signal at a fixed time, and receiving the FSK signal in the data window based on the received FSK signal in the data window which is time-shifted by one symbol length of the FSK signal for each sampling time. A power spectrum calculator for calculating the power spectrum of the signal only for two oscillation frequencies, an oscillation frequency detector for detecting an oscillation frequency from the power spectrum calculated by the power spectrum calculator, and a signal detected by the oscillation frequency detector. Estimate the original signal as a function from the received signal data based on the oscillation frequency Original signal estimating means, noise signal analysis means for analyzing the noise component of the received signal data by taking the difference between the received signal data and the original signal estimated by the original signal estimating means, True S / N ratio calculating means for obtaining the S / N ratio with the level of the noise component when there is a signal, and transmission signal level setting means for setting the level of the transmission signal based on the result of the true S / N ratio calculating means. And
A wireless transmission signal level setting method, wherein a transmission signal level of a master unit or a slave unit is sequentially controlled so that an S / N ratio obtained by the true S / N ratio calculation unit is constant.