JPH112651A - Estimation device of signal power ratio - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately estimate desired wave to interference wave signal power ratio (SIR) by obtaining a plurality of delayed signal delayed in turn for one bit period of sign series from a correlator output and calculating the sum of squares of its in-phase component and rectangular component. SOLUTION: By receiving a radio wave spectrum-diffused with a correlator 105, correlation detection is conducted using a diffusion sign corresponding to the diffusion sign used in transmission side for the received signal. With a delay line with a tap 106, (n) delay signal delayed in turn for one bit period of the diffusion sign is obtained from the output of the correlator 105 and with a sum of square calculation part 107, the sum of square of the in-phase component and rectangular component of the (n) delayed signals from the delay line with tap 106 is calculated. In the SIR estimation part 108, the estimation of SIR is calculated from the sum of square of the in-phase component and the rectangular component of (n) delayed signal with a SIR calculation part 110. By this, SIR estimation with little error becomes possible without requiring demodulation proceeding and an additional circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio signal (desired wave) desired to be received and a radio signal (interference wave) not desired to be received mixed with the desired signal power of the radio signal. It is used for estimating the interference wave signal power ratio. INDUSTRIAL APPLICABILITY The present invention is suitable for use in control for reducing a reception power difference generated by a difference in the distance between mobile stations in mobile communication.

[0002]

2. Description of the Related Art Code Division Multiple Access
In mobile communication using (please Access: CDMA), when multiple mobile stations transmit to one base station, if the received power from each mobile station is almost equal, the spreading code is Because of the difference, a radio signal from a desired mobile station can be received separately from a radio signal from another mobile station.

However, as a mobile station moves,
The distance of each mobile station from the base station varies, and even when each mobile station transmits at the same transmission power, the received power at the base station has various values for each mobile station. As described above, there are mobile stations in which signals cannot be distinguished due to various values of received power.

Therefore, it is necessary to perform control such that the transmission power of a mobile station located near the base station is reduced and the transmission power of a mobile station located far from the base station is increased.

Therefore, the base station measures the ratio of the received power from another mobile station to the received power from one mobile station,
By transmitting a signal for controlling transmission power to each mobile station, the reception power at the base station is kept constant regardless of the distance of each mobile station.

For this purpose, it is required to accurately estimate a desired signal power to interference signal power ratio (hereinafter referred to as SIR). A conventional example of this SIR estimating device will be described with reference to FIG. FIG. 10 is a diagram showing a conventional SIR estimating apparatus. The SIR estimating device shown in FIG. 10 is provided in spread spectrum receiver 100. Here, code division multiple access (CDM) is performed using spread spectrum technology.
The case where A) is performed will be described. However, a radio signal modulated using a code sequence is received without using a spread spectrum technique, and correlation is detected by a receiving side using a code sequence corresponding to the code sequence to perform correlation detection. Can be similarly described.

[0007] In Fig. 10, spread spectrum (shown as SS in the figure) transmitters 601 to 603 generate signals that are spread spectrum using spreading codes assigned to users # 1 to #M, respectively. The signal is converted to a high frequency band signal. FIG. 10 shows the spread spectrum transmitters 601 to 601.
Reference numeral 603 denotes a case where the number is M, that is, the number of transmitting users is M.

[0008] M spread spectrum transmitters 601 to 60
3 are M transmission antennas 604 to 60
6 is transmitted. Signals transmitted from transmitting antennas 604 to 606 are received via receiving antenna 101 and input to spread spectrum receiver 100.

The spread spectrum receiver 100 includes a high frequency section down converter 102, an automatic gain controller (AGC) 10
3. Quadrature detector 104, correlator 105, demodulator / RAK
An E combining unit 613 is provided.

[0010] The signal received by the receiving antenna 101 is
A quadrature detector 104 via a high frequency section down converter 102 for performing high frequency demodulation and an automatic gain controller (AGC) 103
Is input to In the quadrature detector 104, the received signal frequency-converted to the intermediate frequency band (IF) by the high frequency unit downconverter 102 is further frequency-converted to a base band or a band close to the base band, and an in-phase component (I component) and a quadrature component (Q ) And each component is input to a correlator 105 for performing despreading.

The correlator 105 includes, for example, the transmitting antenna 6
When the signal transmitted from the receiver 04 is a desired wave, correlation detection is performed on the desired wave using a spreading code corresponding to the spreading code used on the transmission side. The correlator 105 can be realized by a matched filter that can process a plurality of delayed signals with one correlator, but if the correlator 105 outputs a correlation output for one peak power, Can be realized by arranging a plurality of correlators corresponding to a plurality of delay signals.

In this specification, a main signal received first and a signal received after the main signal has been transmitted and received later than the main signal are referred to as a delayed signal. To

The outputs of the I and Q components of the correlator 105 are the sum of the correlation values of the in-phase and quadrature components for the desired wave and the correlation values for the (M-1) interference signals from the transmitting antennas 605 to 606. Become. In an environment where multiple delay signals appear, a correlation value appears for each bit length of the spreading code.

Each component output of the correlator 105 is a demodulator
This is input to the RAKE combining unit 613. Demodulator / RAKE
The combining unit 613 performs diversity combining (RA) on the input outputs of the plurality of correlators 105 by the maximum ratio combining method.
KE combining) to obtain a demodulated signal.

The output of the demodulator / RAKE combining circuit 613 is divided into two, one of which is input to a decoder 615, which decodes the signal and outputs it as a decoded signal. The other output of the demodulator / RAKE combining circuit 613 is input to the SIR estimator 614.

The SIR estimator 614 obtains the desired signal power as the sum of squares of the average values of the in-phase and quadrature components of the demodulated signal in a predetermined measurement section. On the other hand, the interference wave power is determined as the average value of the in-phase and quadrature components of the demodulated signal and the variance of the demodulated signal in a predetermined measurement section. The ratio between the desired signal power and the interference signal power is the estimated SIR value.

FIG. 10 shows a case in which M transmitters are prepared for M users and reception is performed for the transmitted signal. SIR detection can be performed in the same manner when receiving a signal transmitted by the transmitter of (1).

[0018]

In such a conventional example, for example, in the literature "Kiyo, Yasumoto, Okumura, Toi, DS-CDMA"
As described in “Reception SIR detection method using pilot symbols in transmission power control”, IEICE, RCS96-74, 1996-08, estimation error is large in SIR estimation using a demodulated signal, There is a problem that an additional circuit such as an outer loop for adjusting the SIR estimation error from the bit error rate or the frame error rate is required.

The present invention has been made in such a background, and provides a signal power ratio estimating apparatus capable of performing SIR estimation with a small error without requiring demodulation processing or an additional circuit. With the goal. The present invention provides an SI system with a small error even in an environment where a plurality of delayed signals exist.
It is an object to provide a signal power ratio estimating device capable of performing R estimation.

[0020]

SUMMARY OF THE INVENTION According to the present invention, it is possible to perform SIR estimation even in an environment where a delayed signal exists, without requiring a demodulation process or an additional circuit. The most important feature is that a simple and highly accurate SIR estimation effect is obtained because a relational expression between the output and the SIR is used.

That is, a first aspect of the present invention is a signal power ratio estimating apparatus which receives a radio signal modulated by a predetermined code sequence, and uses a code sequence used on a transmission side for the received signal. And a means for estimating SIR from the output of the correlator. A feature of the present invention is that the estimating means obtains n (n is an integer of 1 or more) delayed signals sequentially delayed by one bit period of the code sequence from the output of the correlator. Means for calculating the sum of squares of the in-phase component and the quadrature component of the n delayed signals obtained by the delay means;
Means for calculating an estimated value of the SIR according to the calculation result of the sum of the squares.

As a result, SIR estimation with a small error can be performed without the need for demodulation processing or additional circuits.

A plurality of n correlators are provided corresponding to the n delayed signals, and the means for obtaining the delayed signals includes means for obtaining n delayed signals from the outputs of the n correlators. The means for obtaining the delay signal may include a plurality of n delay means corresponding to the n delay signals and each having a different delay time.

The means for calculating the estimated value includes, for the sum of squares of the in-phase and quadrature components of the n delayed signals obtained by the delay means, the desired wave components at time t as D1 (t) and D2 (t −τ),…, Dn (t− (n−1) τ) When the interference wave components are U1 (t), U2 (t−τ),…, Un (t− (n−1) τ), estimate the SIR (t) SIR of SIR (t) = (| D1 (t) | 2 + | D2 (t-τ) | 2 + ... + | Dn
(t- (n-1) τ ) | 2) / (| U1 (t) | 2 + | U2 (t-τ)
| ² + ... + | Un (t− (n−1) τ) | ² ) = ( _{i = 1 to n} Σ |
Di (t− (i−1) τ | ² ) / ( _{i = 1 to n} Σ | Ui (t− (i−1) τ
It is desirable to include means for calculating as | ² ).

Thus, even in an environment where a plurality of delay signals exist, SIR estimation with a small error can be performed.

As described above, in this specification, the delayed signal including the first received main signal and the signal received after receiving the main signal generated by transmitting the main signal are received. Here, the desired wave components D1 (t), D2 (t−τ),..., Dn (t− (n−1) τ) are represented by D1
(t) corresponds to the main signal of the desired wave component, and D2 (t−τ),.
n (t- (n-1) [tau]) corresponds to a signal received after the transmission of the main signal and delayed from the reception of the main signal.

Similarly, interference wave components U1 (t), U2 (t−τ),
, Un (t− (n−1) τ) is such that U1 (t) corresponds to the main signal of the interference wave component, and U2 (t−τ),…, Un (t− (n−1) τ) Corresponds to the signal transmitted and received from the reception of the main signal generated by the transmission of the main signal.

When n is "2", the means for calculating the estimated value includes a desired wave component at time t for the sum of squares of the in-phase and quadrature components of the two delayed signals obtained by the delay means. Let D1 (t) and D2 (t−τ) be the interference wave components U1 (t) and U2 (t−τ), and estimate the SIR SIR (t) as SIR (t) = (| D1 (t ^{) | 2 + | D2 (t} -τ) | 2) / (| U1
^{(t) | 2 + | U2} (t-τ) | 2) preferably includes a means for calculating a.

Further, the estimated value SIR (j) of the SIR up to the j-th section a is set as SIR (j) = (1 / a) · ( _{i = (j−a + 1) to} jΣSIR (i)) It is desirable to include means for calculating.

A second aspect of the present invention is a signal power ratio estimating method, which receives a radio signal modulated by a predetermined code sequence and converts the received signal into a code sequence used on the transmission side. This is a signal power ratio estimation method for performing correlation detection using a corresponding code sequence and estimating SIR from the output of the correlation detection. The present invention is characterized in that n (n is an integer of 1 or more) delayed signals sequentially delayed by one bit period of the code sequence from the output of the correlation detection, and the n delayed signals are obtained. Of the in-phase component and the quadrature component are calculated, and the SI is calculated according to the calculation result of the n square sums.
It is in calculating the estimated value of R.

According to a third aspect of the present invention, there is provided a machine-readable recording medium which is installed in a hardware device including a program control circuit so that the device becomes a device for executing the method. Machine readable recording medium.

[0032]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a block diagram of a signal power estimation apparatus according to a first embodiment of the present invention.

The present invention relates to a correlator 105 for receiving a spread spectrum radio signal and performing correlation detection on the received signal using a spreading code corresponding to the spreading code used on the transmission side, A signal power ratio estimating apparatus including an SIR estimating unit 108 as a means for estimating the SIR from the output of the unit 105.

The feature of the present invention is that S
IR estimating section 108 includes tap delay line 106 as delay means for obtaining n (n is an integer of 1 or more) delayed signals sequentially delayed by one bit period of the spreading code from the output of correlator 105; A sum-of-squares calculator 107 as means for calculating the sum of squares of the in-phase component and the quadrature component of the n delayed signals obtained by the tapped delay line 106;
The SIR calculator 110 as means for calculating an estimated value of the SIR in accordance with the calculation result of the sum of the squares.

The correlator 105 is realized by a matched filter capable of processing a plurality of delayed signals with one correlator.

The SIR calculation section 110 calculates the desired wave components at time t with respect to the sum of squares of the in-phase component and the quadrature component of the n delayed signals obtained by the tapped delay line 106 at D1 (t) and D2 (t −τ),…, Dn (t− (n−1) τ) When the interference wave components are U1 (t), U2 (t−τ),…, Un (t− (n−1) τ), estimate the SIR (t) SIR of SIR (t) = (| D1 (t) | 2 + | D2 (t-τ) | 2 + ... + | Dn
(t- (n-1) τ ) | 2) / (| U1 (t) | 2 + | U2 (t-τ)
| ² + ... + | Un (t− (n−1) τ) | ² ) = ( _{i = 1 to n} Σ |
Di (t− (i−1) τ | ² ) / ( _{i = 1 to n} Σ | Ui (t− (i−1) τ
| ² ).

Here, the desired wave components D1 (t), D2 (t−τ),
.., Dn (t− (n−1) τ), where D1 (t) corresponds to the main signal of the desired wave component, and D2 (t−τ),..., Dn (t− (n−1) τ) Corresponds to a signal received after the reception of the main signal generated by transmission of the main signal.

For example, a radio signal transmitted from one transmission source that the reception side desires to receive is a desired wave, and a signal that first arrives at the reception side from this transmission source is D1 (t). D2 (t−τ),..., Dn (t− (n−1) τ) are the signals generated by transmitting the signal D1 from the transmission source.
It is a signal sent and received from the reception of D1 (t).

Similarly, interference wave components U1 (t), U2 (t−τ),
, Un (t− (n−1) τ) is such that U1 (t) corresponds to the main signal of the interference wave component, and U2 (t−τ),…, Un (t− (n−1) τ) Corresponds to the signal transmitted and received from the reception of the main signal generated by the transmission of the main signal. For example, a radio signal transmitted from a transmission source other than one transmission source that the receiving side desires to receive is an interference wave. Although the number of transmission sources of the interference wave may be one or plural, it is treated as one interference wave regardless of the number of transmission sources. The signal that first arrives at the receiving side from the source of the interference wave is U1 (t). U2 (t
−τ),..., Un (t− (n−1) τ) are signals received after the reception of the signal U1 (t) generated by the transmission of the signal U1.

[0040]

【Example】

(First Embodiment) A first embodiment of the present invention will be described. Here, a case of a CDMA system in which multiple access is performed using spread spectrum will be described. However, without using a spread spectrum technique, a radio signal modulated using a code sequence is received, and the code sequence is transmitted to the receiving side. All communication systems that perform correlation detection by correlating with a corresponding code sequence can be similarly described.

The receiving section is roughly composed of a spread spectrum receiver (SS receiver) 100 and a receiving antenna 101. The SS receiver 100 includes a high frequency section down converter 102, an automatic gain controller (AGC) 103, a quadrature detector. , A correlator 105, a delay line with tap 106, a sum of squares calculation section 107, and an SIR estimation section 108.

This SIR estimating section 108 is a square sum combining section 1
09, an SIR calculation unit 110, an instantaneous SIR output unit 111, and a short section SIR output unit 112.

The case where the desired signal and (M-1) interference waves are received by the receiving antenna 101 as described in the related art will be described. The received signal is input to a quadrature detector 104 via a high frequency section down converter 102 for performing high frequency demodulation and the like, and an automatic gain controller (AGC) 103.

The quadrature detector 104 frequency-converts the received signal in the intermediate frequency band into a base band or a band close to the base band, and outputs the in-phase component and the quadrature component separately. The in-phase and quadrature component signals of the received signal are input to a correlator 105 for performing despreading. The correlator 105 performs correlation detection on the in-phase and quadrature components of the received signal using a spreading code corresponding to the spreading code used by the transmitting station performing communication. The correlator 105 is a matched filter that can process a plurality of delayed signals with one correlator.

At each output of the in-phase (I) and quadrature (Q) components of the correlator 105, the correlation values of the I and Q components with respect to the combined signal of the desired wave and the interference wave appear. The correlator output is input to a tapped delay line 106. In the tap delay line 106, the correlator output is sequentially delayed for each code 1 bit length, and a delayed signal is output from each tap. The I and Q components of each delay signal are input to the sum of squares calculation section 107, and the sum of squares of the I and Q components of each delay signal is calculated. The output of the sum-of-squares calculation unit 107 is the
The sum of the squares of the respective delayed signals input to the square sum combining unit 109 is synthesized. The output of the square sum combining unit 109 is input to the SIR calculating unit 110, and the SI corresponding to the output of the square sum combining unit is output.
Calculate the R estimate. This estimated SIR value is input to the instantaneous SIR output unit 111 and the short-range SIR output unit 112.

The instantaneous SIR output unit 111 calculates an average value of a (a is an integer of 1 or more) SIR estimated values and outputs the average value as an instantaneous SIR estimated value. The short section SIR output unit 112 outputs b (b is an integer greater than a)
The average value of the IR estimation values is calculated and output as a short section SIR estimation value. Here, the case of calculating the average value has been described, but the median value can also be applied. If only one of the instantaneous SIR and the short section SIR is required, the instantaneous SIR
Only one of the output unit 111 and the short section SIR output unit 112 needs to be connected to the SIR calculation unit 110.

Hereinafter, the operation of the SIR estimating apparatus of the embodiment will be described. FIG. 2 is a diagram showing a desired signal power, an interference signal power, and a delay signal thereof.

In the receiving antenna 101, the main signal as shown in FIG. 2 and the delay time from the main signal Tb (code 1 bit length)
A case where one delayed signal is received will be described.

Since the output signal S (t) of the quadrature detector 104 has been normalized by the AGC 103 at the preceding stage,
It can be expressed as in equation (1). S (t) = [(D1 (t) + D2 (t−τ)) + (U1 (t) + U2 (t−τ))] / [| (D1 (t) + D2 (t−τ)) + ( U1 (t) + U2 (t−τ)) |] (1) However, S (t), D1 (t), D2 (t−τ), U1 (t), U2 (t−
τ) is a complex signal represented by the sum of an in-phase component and a quadrature component, and D1 (t), D2 (t−τ) and U1 (t), U2 (t−τ) are the inputs of the automatic gain controller 103. The desired wave component and the interference wave component of the signal.

Accordingly, since the correlation value of each delay signal with respect to the desired signal appears at the output of the correlator 105, the c output Sc (t) and the d output Sd (t) of the tapped delay line 106 are output.
Can be expressed as in equation (2). c output Sc (t) = D1 (t) / | (D1 (t) + D2 (t−τ)) + (U1 (t) + U2 (t−τ)) | d output Sd (t) = D2 (t −τ) / | (D1 (t) + D2 (t−τ)) + (U1 (t) + U2 (t−τ)) | (2) As in the CDMA method of performing multiple access using spread spectrum, When each user uses a code orthogonal to each other, the composite k (t) of the sum of squares of the in-phase component and the quadrature component of the correlator output is described in the literature "Maehara, Nakamura, Takanashi, Tanaka," It can be expressed by equation (3) from "Examination of ratio combining diversity", 1997 IEICE General Conference, B-5-99. k (t) = [| D1 (t) | 2 + | D2 (t-τ) | 2] / [(| D1 (t) | 2 + | D2 (t-τ) | 2) + (| U1 ( ^{t) | 2 + | U2 (} t-τ) | 2)] (3) (3) using the equation can represent SIR as (4). SIR (t) = (| D1 (t) | 2 + | D2 (t-τ) | 2) / (| U1 (t) | 2 + | U2 (t-τ) | 2) = k (t) / (1−k (t)) (4) Thus, the sum of squares of the in-phase and quadrature components of the correlator output
The received SIR can be estimated from k (t).

J output from the instantaneous SIR output unit 111
The instantaneous SIR estimated value SIR ′ (j) is calculated by the SIR calculator 1
The outputs of the SIR estimates from 10 are sequentially SIR (1),
SIR (2),..., SIR (i) are represented by equation (5).

SIR ′ (j) = 1 / a · _{i = (j−a + 1) to} jΣSIR (i) (5) The k-th short-section SIR estimated value SIR output from the short-section SIR output unit 112 ″ Is expressed by equation (6).

SIR ″ (k) = 1 / b · _{i = (k−b + 1) to} kΣSIR (i) (6) From the equations (5) and (6), the instantaneous and short section (average) SI
R can be estimated. The calculation inside the SIR estimating unit 108 is calculated using, for example, a DSP (Digital Signal Processor) or the like, and the instantaneous SIR estimation value and the short-term SIR
Output an estimate.

FIG. 3 is a flowchart showing the operation of the first embodiment of the present invention. First, the sum of the squares of the in-phase component and the quadrature component of the delay signal is calculated (S1). Then, the sum of the sum of the squares of the delay signals is calculated [Equation (3)] (S2). The estimated value is calculated [Equation (4)] (S3). The case where two delayed signals (including the main signal) exist has been described above. However, even when there are three or more delayed signals, SIR estimation can be performed in the same manner.

An example of a simulation result of SIR estimation is shown below. Table 1 shows the specifications of the simulation.

[0056]

[Table 1] FIG. 4 is a diagram showing a simulation result at the time of static characteristics without fading in the present invention. Receiving SIR on horizontal axis
And the vertical axis represents the estimated SIR value. The received SIR is the actual SIR received at the antenna. Also, S in the figure
The IR estimation ideal value indicates an ideal value when the actual SIR is estimated without error. FIG. 4 shows that the simulation result of the present invention almost coincides with the ideal value of SIR estimation, and it can be seen that SIR estimation is possible according to the present invention.

FIGS. 5 and 6 are diagrams showing simulation results at the time of dynamic characteristics in the present invention. Using a two-wave median model, each path was independent Rayleigh variation. FIG. 5 shows the case where the maximum Doppler frequency fd is 10 Hz, and FIG. 6 shows the case where the maximum Doppler frequency fd is 100 Hz. The number of bits is taken on the horizontal axis, and the instantaneous SIR is taken on the vertical axis. Since the calculation result of the SIR estimation value is output for each bit with respect to the symbol rate (spread code rate / code length), the horizontal axis is the number of bits. From FIGS. 5 and 6,
It can be seen that the instantaneous SIR estimate according to the invention matches well with the instantaneous received SIR.

FIGS. 7 and 8 show the average reception SI for about one second.
FIG. 9 is a diagram illustrating a relationship between R and an average value of SIR estimated values. The horizontal axis represents the average reception SIR, and the vertical axis represents the average SIR estimated value. 7 shows the case where the maximum Doppler frequency fd is 10 Hz, and FIG. 8 shows the case where the maximum Doppler frequency fd is 100H.
The case of z is shown. 7 and 8, the average SIR estimated value according to the present invention agrees well with the average received SIR value, and is described in the literature “Kiyo, Yasumoto, Okumura, Toi, DS-C
Received SIR Detection Method Using Pilot Symbols in DMA Transmission Power Control ", IEICE, RCS96-74,
SIR with higher accuracy compared to the method of 1996-08 "
It can be seen that the estimation has been performed. Since the short section is an average value for a certain time, the results of FIGS. 7 and 8 show the accuracy of the short section SIR estimation. (Second Embodiment) A second embodiment of the present invention will be described with reference to FIG. FIG. 9 is a block diagram of a main part of a signal power ratio estimating apparatus according to a second embodiment of the present invention. In the first embodiment of the present invention, the correlator 105 has been described as being realized by a matched filter capable of processing a plurality of delay signals with one correlator. Correlators 105 ₁ to 10 that output correlation outputs
This is realized by arranging 5 _n corresponding to a plurality of n delayed signals.

Thus, _n sequentially delayed from the outputs of the correlators 105 _{1 to} 105 _n by one bit period of the code sequence
Can be obtained.

[0060]

As described above, according to the present invention, there is no need for demodulation processing or additional circuits, and S
IR estimation can be performed. Further, the SIR can be estimated even in an environment where a plurality of delay signals exist.

[Brief description of the drawings]

FIG. 1 is a block diagram of a signal power estimation device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a desired signal power, an interference signal power, and a delay signal thereof.

FIG. 3 is a flowchart showing the operation of the first embodiment of the present invention.

FIG. 4 is a diagram showing a simulation result at the time of static characteristics in the present invention.

FIG. 5 is a diagram showing a simulation result at the time of dynamic characteristics in the present invention.

FIG. 6 is a diagram showing a simulation result at the time of dynamic characteristics in the present invention.

FIG. 7 is a diagram showing a relationship between an average received SIR for about one second and an average of SIR estimated values;

FIG. 8 is a diagram showing a relationship between an average reception SIR for about one second and an average of SIR estimation values.

FIG. 9 is a block diagram of a main part of a signal power ratio estimating apparatus according to a second embodiment of the present invention.

FIG. 10 is a diagram showing a conventional example of an SIR estimating device.

[Explanation of symbols]

REFERENCE SIGNS LIST 100 Spread spectrum receiver 101 Receiving antenna 102 High frequency section down converter 103 Automatic gain controller 104 Quadrature detector 105, 105 _{1 to} 105 _n correlator 106 Tapped delay line 107 Square sum calculator 108, 614 SIR estimator 109 2 Multiply-sum combination unit 110 SIR calculation unit 111 Instantaneous SIR output unit 112 Short interval SIR output unit 601 to 603 Spread spectrum transmitter 604 to 606 Transmission antenna 613 Demodulator / RAKE combiner 615 Decoder

Claims (8)

[Claims] 1. A correlator for receiving a radio signal modulated by a predetermined code sequence and performing correlation detection on the received signal using a code sequence corresponding to a code sequence used on a transmission side. Means for estimating a desired signal power to interference signal power ratio from an output of the correlator, wherein the estimating means comprises one bit of the code sequence from the output of the correlator. Means for obtaining n (n is an integer of 1 or more) delayed signals sequentially delayed by a period; and sum of squares of the in-phase component and the quadrature component of the n delayed signals obtained by the means for obtaining the delayed signal. A signal power ratio estimating apparatus, comprising: means for calculating; and means for calculating an estimated value of a desired signal power to interference signal power ratio in accordance with the result of calculating the n sums of squares. 2. The signal power ratio estimating apparatus according to claim 1, wherein the means for obtaining the delay signal includes a plurality of n delay means corresponding to the n delay signals and having different delay times. 3. A plurality of correlators are provided corresponding to the n delayed signals, and a means for obtaining the delayed signals includes:
2. The signal power ratio estimating apparatus according to claim 1, further comprising means for obtaining n delayed signals from outputs of said n correlators. 4. The means for calculating the estimated value includes, for the sum of squares of the in-phase component and the quadrature component of the n delayed signals obtained by the delay means, the desired wave components at time t as D1 (t), D2 (t−τ),..., Dn (t− (n−1) τ) Let the interference wave components be U1 (t), U2 (t−τ),..., Un (t− (n−1) τ) when the estimated value SIR (t) the SIR of the desired wave signal power to interference signal power ratio (t) = (| D1 ( t) | 2 + | D2 (t-τ) | 2 + ... + | Dn
(t- (n-1) τ ) | 2) / (| U1 (t) | 2 + | U2 (t-τ)
| ² + ... + | Un (t− (n−1) τ) | ² ) = ( _{i = 1 to n} Σ |
Di (t− (i−1) τ | ² ) / ( _{i = 1 to n} Σ | Ui (t− (i−1) τ
^2. The signal power ratio estimating apparatus according to claim 1, further comprising means for calculating as | ² ). 5. When the n is “2”, the means for calculating the estimated value includes: determining a sum of squares of an in-phase component and a quadrature component of two delayed signals obtained by the delay unit at a time t; Wave component is D1 (t), D2 (t−τ) When interference wave components are U1 (t) and U2 (t−τ), the estimated value SIR (t) of the desired signal power to interference signal power ratio the SIR (t) = (| D1 (t) | 2 + | D2 (t-τ) | 2) / (| U1
^{(t) | 2 + | U2} (t-τ) | 2) signal power ratio estimation device according to claim 4 including means for calculating a. 6. An estimated value SIR (j) of a desired signal power to interference signal power ratio in the a section up to the j-th section is calculated as SIR (j) = (1 / a). ( _{I = (j-a + 1)} 5. The signal power ratio estimating apparatus according to claim 4, further comprising means for calculating as :) _{j j} SIR (i)). 7. A radio signal modulated by a predetermined code sequence is received, and correlation detection is performed on the received signal using a code sequence corresponding to a code sequence used on a transmission side. A signal power ratio estimating method for estimating a desired signal power to interference signal power ratio from the output of the correlation detection, wherein n (n is 1 or more) sequentially delayed by one bit period of the code sequence from the output of the correlation detection ), And calculates the sum of squares of the in-phase component and the quadrature component of the n delayed signals. According to the calculation result of the n sums of squares, the power of the desired signal versus the interference signal A signal power ratio estimating method comprising calculating an estimated value of a power ratio. 8. A machine-readable recording medium on which software is recorded, which is installed on a hardware device including a program control circuit so that the device executes the method according to claim 7.