JP2002290323A - Radio wave service area evaluation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radio wave service area evaluation device that can evaluate a radio wave from a base station adopting transmission diversity with high accuracy. SOLUTION: A repetitive symbol pattern (A, A, A, A) is multiplied with a received W-CDMA (wideband-CDMA) signal, inverse spread spectrum processing is applied to the resulting W-CDMA signal, symbol information of a common pilot channel corresponding to a 1st antenna is extracted, a repetitive symbol pattern (A,-A,-A, A) is multiplied with the received W-CDMA signal to apply inverse spread spectrum processing to the W-CDMA signal and symbol information of the common pilot channel corresponding to a 2nd antenna is extracted. A mean value of adjacent symbols where signs of the symbol pattern of the 2nd antenna corresponding to each extracted symbol information are different is sequentially calculated and each mean value sequentially calculated is used for tentative symbol information with respect to the corresponding antenna. A desired wave signal power and an interference wave signal power are calculated on the basis of the tentative symbol information.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to W-CDMA (wideband-code division multiple access).
The present invention relates to a radio service area evaluation device for evaluating a radio service area of a base station in a mobile communication network system such as a mobile phone adopting a tiple access method, and in particular, a desired wave signal of a radio wave from a base station adopting transmission diversity. The present invention relates to a radio wave service area evaluation device that can accurately evaluate power and interference signal power.

[0002]

2. Description of the Related Art In a mobile communication network system such as a portable telephone, a number of base stations are installed close to each other in a telephone service area. At each point in the telephone service area, measuring the radio waves from each base station and evaluating the radio wave condition at the corresponding point is very important for installing a new base station or maintaining and maintaining the installed base station. Is important.

A base station employing a transmission diversity system has been proposed in order to cope with a fading phenomenon that occurs when a mobile phone receives a transmission radio wave from each base station. When measuring the radio wave condition at each point in the telephone service area, as shown in FIG. 2, a measurer mounts a measuring device 2 on a measuring vehicle 1 and installs a plurality of base stations 3 in a telephone service area. Move in. Then, while moving, each point receives radio waves 5 from a pair of antennas 4a and 4b of each base station 3, measures the received signal level of each radio wave 5, and evaluates each radio wave state at the corresponding point.

In a mobile communication network system adopting the W-CDMA system as a communication system, each radio wave 5 includes a W-CDMA signal 6 shown in FIG. This WC
In the DMA signal 6, the common pilot channel (CPICH) 7 and the synchronization channel (S
CH) 8, a plurality of data channels 9 (CH1 to CH
N), and other channels 9 are included in a state where the signals are combined.

[0005] Common pilot channel (CPICH) 7
Are spread spectrum by a code (for example, a Gold code) generated by a 9-bit primary code and a 4-bit secondary code that specify each base station 3. Then, this common pilot channel (CPIC)
H) One frame (about 10 ms) in 7 is composed of 150 symbols, and one symbol is composed of 256 chips.

Further, when evaluating the service area of each base station, it is necessary to measure not only the received power of the common pilot channel but also the influence of interference waves.

Further, in a mobile communication network system adopting the W-CDMA system, SIR (signal to interference ratio (signal to interference signal power ratio) measurement) is required to solve the problem of distance between mobile stations. A transmission power control using the same has been proposed. Therefore, the measurement of the desired signal power and the interference signal power of the common pilot channel is an important measurement item for the radio wave service area evaluation device.

A method for measuring the radio wave 5 from the base station 3 employing the transmission diversity will be described with reference to FIGS. In the transmission diversity, as shown in FIG. 5, a common pilot of A, A, A, A, A, A, A, A, A, A, A, A,. Assuming that a channel signal is output, in the case of the base station 3 supporting transmission diversity, A, A, A, A, A, A, A, and A are transmitted from the first antenna 4a in the same one symbol unit as in the base station 3. A signal (radio wave 5a) of a common pilot channel of A, A, A, A, A, A,... A signal (radio wave 5b) of a common pilot channel of A, -A, -A, A, A, -A, -A, A, -A, -A, A, A, ... is output from the second antenna 4. Is done.

When the mobile station (measuring device 2) receives signals (radio waves 5a, 5b) from the graveyard station 3, attenuation occurs. Assuming that the transmission characteristic of the signal (radio wave 5a) from the first antenna 4a is α and the transmission characteristic of the signal (radio wave 5a) from the second antenna 4b is β, the input terminal of the mobile station (measuring device 2) Then, (α + β) A, (α-β) A, (α-β) A, (α + β) A, (α + β) A,
As shown at the bottom of FIG. 5, a signal of a common pilot channel whose amplitude fluctuates in units of two symbols such as (α-β) A,.

A method for calculating the SIR from the in-phase and quadrature components after despreading in the common pilot channel of the DS-CDMA signal is described in the literature [Kiyo, Yasumoto, Okumura, and Doi. The received SIR measurement method used is shown in IEICE, IEICE Technical Report, RCS96-74, PP57-62, 1996].

That is, the in-phase component and the quadrature component of the common pilot channel after despreading are individually averaged, and the desired signal power S is obtained from the square sum P. Then, the interference wave signal power I is obtained by calculation as the variance σ ² of each symbol.

Specifically, assuming that the signal An from the base station 3 is a combination of the desired wave Rn and the interference wave In. An = Rn + In., Where n is: Indicates the n-th symbol, and An, Rn, and In. are all represented by complexly displayed information in units of received symbols.

After matching the first to fourth quadrants of each symbol on the complex coordinates shown in FIG.
When the quadrature component each averaged separately 2 Noyawara calculating, desired wave signal power S ^{_{is, S = | A AV | 2}} = | (1 / N) (A 1 + A 2 + A 3 +, ..., + A N ^{) | 2 = | (1 /} N) (R 1 + R 2 +, ..., R N + I 1 + I 2 +, ..., + I N) | 2 = | R AV + I AV | 2 ... (1) A AV: phase component of the received symbol, the value R _AV were averaged separately quadrature components, respectively: the average value I _AV of the desired signal Rn: the average value of the interference signal in.

Assuming that the interference wave In is normally distributed with respect to the desired wave Rn, the average value I _AV of the interference wave In is "0".
Therefore, the desired signal power S in the equation (1) becomes S = | A _AV | ² = | R _AV + I _AV | ² = | R _AV | ² (2) Is obtained by the equation (1).

On the other hand, the interference wave signal power I is obtained from the variance σ ^{2 for} each symbol as follows. I = (1 / N) ( | A 1 -R AV | 2 + | A 2 -R AV | 2 +, ... ..., + | A N -R AV | 2) ... (3) where, (2) Expanding equation (3) using A _AV = R _AV in the equation, I = (1 / N) (| R ₁ + I ₁ -R _AV | ² + | R ₂ + I ₂ -R _AV | ² +,. _{..., + | R N + I} N -R AV | 2) = (1 / N) {(| R 1 -R AV | 2 + | I 1 | 2 + 2I 1 | R 1 -R AV |) + (| R ^{_{2 -R AV | 2 + | I}} 2 | 2 + 2I 2 | R 2 -R AV |) +, ... + (| R N -R AV | 2 + | I N | 2 + 2I N | R N -R AV | ) A (3a) Here, since the desired wave (common pilot channel) Rn transmitted from the base station is considered to be constant, the term | Rn−R _AV | in equation (3) can be ignored. Equation (4) is obtained.

[0016] I = (1 / N) ( | I 1 | 2 + | I 2 | 2 +, ..., + | I N | 2) ... (4) Therefore, interference signal power I in (3) I get it.

As described above, when the desired signal power S and the interference signal power I are obtained, the SIR indicated by the ratio between the final signal level and the interference signal level is determined based on the information.
Ask for.

[0018]

However, the desired signal power S and the interference signal power I are obtained by the above-described method.
Even in the method of obtaining the SIR based on such information, there are the following problems to be solved.

That is, in order to actually obtain the desired signal power S and the interference signal power I in the above-described method, as described above, the complex coordinates shown in FIG. It is necessary to align the quadrants above, but if the symbol points are near the boundaries of the quadrants, it will be difficult to align the quadrants.

If the symbol rates on the transmitting side (base station side) and the receiving side (measuring device side) do not match, the symbol points after despreading will rotate on the complex coordinates. Appear in the calculation result of the interference wave signal power I.

Further, as shown at the bottom of FIG. 5, a signal received from a base station having a pair of antennas and employing transmission diversity has a large fluctuation in amplitude in symbol units. The level fluctuation adversely affects the calculation result of the interference wave signal power calculated as the variance of the symbol.

In the radio wave service area evaluation of the base station adopting the transmission diversity, not only the evaluation of the radio wave 5 obtained by combining the pair of radio waves 5a and 5b from the corresponding base station but also the evaluation of the radio wave 5 from each of the individual antennas 4a and 4b Each radio wave 5a, 5
There is a demand to separate the transmission characteristics α and β in b and evaluate them separately.

[0023] The present invention has been made in view of such circumstances, the common pilot channel after being inverse spread spectrum by averaging the symbols neighbor different unsigned, the received signal level Radio service area evaluation that is not affected by fluctuations, can eliminate the effects of quadrant movement or rotation of symbol points on complex coordinates, and can individually evaluate radio waves from each antenna of a base station that employs transmit diversity The aim is to provide a method.

[0024]

The present invention receives a W-CDMA signal transmitted to a mobile station from a base station having first and second antennas and employing transmission diversity, and receives the signal. The present invention relates to a radio service area evaluation device that provides information for evaluating a radio service area of a base station based on a signal level.

In order to solve the above problem, the radio wave service area evaluation apparatus of the present invention multiplies a received W-CDMA signal by a repetition symbol pattern of (A, A, A, A) to multiply the received W-CDMA signal. A first despreading unit for performing spectrum despreading on the W-CDMA signal and extracting a predetermined number of continuous first symbol information of a common pilot channel corresponding to the first antenna;
-The CDMA signal is multiplied by a repetitive symbol pattern of (A, -A, -A, A) to perform spectrum despreading on the W-CDMA signal, thereby obtaining a common pilot channel corresponding to the second antenna. A predetermined number of consecutive second
A second despreading unit that extracts the symbol information of the following, and in the extracted first symbol information, sequentially calculates the average value of adjacent symbols having different symbols of the symbol pattern of the corresponding second antenna, A first averaging unit that outputs the sequentially calculated average values as first temporary symbol information (17a) corresponding to a new corresponding antenna;
In the extracted second symbol information, the corresponding second symbol
The second average for sequentially calculating the average value of adjacent symbols having different symbols of the symbol pattern of the antenna and outputting the sequentially calculated average value as second temporary symbol information corresponding to a new corresponding antenna A first processing unit that calculates a desired signal power and an interference signal power for the radio wave of the first antenna from the first temporary symbol information corresponding to the first antenna output from the first averaging processing unit. 1 signal power calculation unit, and the desired wave signal power and the interference wave signal power for the radio wave of the second antenna from the second temporary symbol information corresponding to the second antenna output from the second averaging processing unit. A second signal power calculator for calculating,
And the desired signal power and the interference signal power calculated by the second signal power calculator, and based on them, the combined desired signal power and the combined interference signal power corresponding to the entire base station. And a composite signal power calculator for calculating

First, the operating principle of the radio wave service area evaluation apparatus thus configured will be described. As described above, assuming that the transmission characteristic of the signal (radiowave 5a) from the first antenna 4a in FIG. 4 is α and the transmission characteristic of the signal (radiowave 5a) from the second antenna 4b is β, At the input terminal of (measuring device 2), a signal in symbol units shown in Expression (5) is received.

(Α + β) A, (α-β) A, (α-β) A, (α + β) A, (α + β) A, (α-β) A, ... (5) Then, in the first despreading unit, (A, A, A,
By multiplying the repetitive symbol pattern of A), a first common pilot channel corresponding to the first antenna 4a represented by the equation (6) is obtained.

(Α + β) A, (α-β) A, (α-β) A, (α + β) A, (α + β) A, (α-β) A, ... (6) On the other hand, in the second despreading unit, (A, -A, -A,
By multiplying the repetitive symbol pattern of A), a second common pilot channel corresponding to the second antenna 4b shown in Expression (7) is obtained.

(Α + β) A, (β-α) A, (β-α) A, (α + β) A, (α + β) A, (β-α) A, ... (7) Here, a pair of averaging processing units, (6), in each symbol information represented by the formula (7), the level of each other adjacent symbols that are different from each other by a predetermined value or more are sequentially calculated,
The sequentially calculated average values are output as provisional symbol information corresponding to the new first and second antennas 4a and 4b and represented by equations (8) and (9).

First antenna 4a (first temporary symbol information) side {(α + β) A + (α-β) A} / 2, {{α-β} A + (α + β) A) / 2 , {(α + β) A + (α-β) A} / 2, ｛(α + β) A + (α-β) A｝ / 2, ... = αA, αA, αA, αA, αA, αA, ... ... (8) Second antenna 4b (second temporary symbol information) side {(α + β) A + (β-α) A} / 2, {(β-α) A + (α + β) A} / 2, {(α + β) A + (β-α) A} / 2, {(α + β) A + (β-α) A} / 2, ... = βA, βA, βA, βA, βA, βA, (9) As described above, in the despreading process, a specific repetition pattern (1,1,1,1,) or (1, -1,1, -1,1) is adopted, and the adjacent symbol is averaged. By creating the first and second temporary symbol information, it is possible to equalize the level value of each symbol in the first and second temporary symbol information.

Further, as shown by the equations (8) and (9), the transmission characteristics α on the side of the first antenna 4a and the side of the second antenna 4b,
β can be separated. Therefore, when the desired wave signal power and the interference wave signal power are obtained using the first temporary symbol information expressed by the equation (8), the desired wave signal power and the interference wave signal power of the radio wave arriving from the first antenna 4a side are calculated. Can be calculated. Further, when the desired wave signal power and the interference wave signal power are obtained using the second temporary symbol information expressed by the equation (9), the desired wave signal power and the interference wave signal power of the radio wave from the second antenna 4b are calculated. Can be calculated.

Also, by combining these, the desired signal power and the interference signal power of the radio wave of the entire base station can be calculated.

Further, according to the present invention, each averaging processing section in the radio wave service area evaluation apparatus of the present invention determines a code multiplied by an averaging process between symbols based on a signal level difference between symbols. , Averaging symbols having different codes.

Further, the present invention compares and contrasts adjacent averaged symbol values of each provisional symbol information output from each averaging processing unit with the radio service area evaluation apparatus of the above-mentioned invention. Accordingly, a sign determination unit for determining whether the combination of symbols to be averaged in each averaging unit is good or bad is added.

When the wrong symbol combination is performed,
Since the value is extremely different between adjacent symbols after averaging, the error is immediately noticed. By adding such a code determination unit, the reliability of the averaging process in each averaging unit is improved.

[0036]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram illustrating a schematic configuration of the radio wave service area evaluation device according to the embodiment. 2 and 4 are denoted by the same reference numerals, and detailed description of overlapping portions will be omitted.

Each radio wave 5 emitted from the first and second antennas 4a and 4b of the base station 3 employing the transmission diversity.
a and 5b are received by the antenna 11 and input to the RF (high frequency) processing unit 12. The RF (high frequency) processing unit 12
The frequency of the high-frequency W-CDMA signal 6 included in each of the radio waves 5a and 5b is converted to an intermediate frequency and quadrature-demodulated to form a baseband W-CDMA signal 6 as first and second despreading units. First and second correlators 13
a and 13b.

Each despreading code generator 14a, 14b
-Generate a despreading code for extracting a common pilot channel for each base station 3 included in the CDMA signal 6, and apply it to the first and second correlators 13a and 13b.

The first correlator 13a converts the input baseband W-CDMA signal 6 into (A, A, A,
This W-CDM is multiplied by the repeated symbol pattern of A).
The spectrum despreading is performed on the A signal 6, and the symbol information 15a of the common pilot channel corresponding to the first antenna 4a is extracted and transmitted to the next averaging processing unit 16a.

The averaging section 16a outputs the symbol information 15
a, the average value of adjacent symbols whose levels are different from each other by a predetermined value or more is sequentially calculated, and the sequentially calculated average values are used as common pilots corresponding to the first antenna 4a corresponding to the new first antenna 4a. The temporary symbol information 17a of the channel is transmitted to the next power calculator 18a.

The power calculating unit 18a includes an averaging processing unit 16a.
Calculates the desired signal power Sa and the interference signal power Ia for the radio wave 5a from the first antenna 4a from the temporary symbol information 17a corresponding to the first antenna 4a output from the It is sent to the display control unit 22.

On the other hand, the second correlator 13b applies (A,-) to the input baseband W-CDMA signal 6.
A, -A, A) is multiplied by a repetitive symbol pattern to perform spectrum despreading on the W-CDMA signal 6, and extracts symbol information 15b of a common pilot channel corresponding to the second antenna 4b, and it sends to the next averaging processing <br/> processing section 16a.

The averaging section 16b outputs the symbol information 15
b, the average values of adjacent symbols having different levels by a predetermined value or more are sequentially calculated, and the sequentially calculated average values are used as temporary symbol information 17b of the common pilot channel corresponding to the new second antenna 4b. To the power calculation unit 18b.

The power calculating unit 18b includes an averaging processing unit 16b
Calculates the desired signal power Sb and the interference signal power Ib for the radio wave 5b from the first antenna 4b from the temporary symbol information 17b corresponding to the first antenna 4b output from the It is sent to the display control unit 22.

The combined signal power calculator 21 calculates the desired signal power S calculated by the respective signal power calculators 18a and 18b.
Based on a and Sb and interference wave signal powers Ia and Ib, combined desired signal power S and combined interference wave power I are calculated and sent to the next display control unit 22.

The display controller 22 calculates the calculated first and second
, The desired wave signal powers Sa, Sb of the radio waves 5a, 5b of the antennas 4a, 4b, and the desired wave signal powers S, 5a,
5b, the respective interference wave signal powers Ia and Ib and the combined interference wave signal power I are displayed on the display 23.

The sign determination processing section 19 is provided for each of the averaging processing sections 1
Temporary symbol information 17a, 1a output from 6a, 16b
7b, if the levels between the symbols are extremely different, it is determined that there is an error in the combination of the symbols to be averaged, and the information is determined by each of the averaging units 16a, 16b. If there is an error in the combination of symbols to be averaged, the averaging processing unit having the error changes the combination of symbols to be averaged and outputs the temporary symbol information again.

Next, the specific processing operation of each section will be described using equations. The despreading route in each of the correlators 13a and 13b is omitted and considered, and the transmission data An (n =
1.2.3,...) Is a desired wave signal Rn (n = 1.2.
..) And the interference wave signal In (n = 1.2.3,...), Can be expressed as An = Rn + In. In the input bridge of this evaluation device, (5) By substituting the equation into the equation, the equation (10) is obtained.

(Α + β) (R ₁ + I ₁ ), (α-β) (R ₂ + I ₂ ), (α-β) (R ₃ + I ₃ ), (α + β) (R ₄ + I ₄ ), (α + β) (R ₅ + I ₆ ), (α-β) (R ₇ + I ₈ ),... (10) For the first antenna 4 a, 1.1,
The multiplication by the repetition pattern of (1), (1)
If the averaging process is performed for the adjacent symbols in a, the first temporary symbol information 17a shown in Expression (11) is obtained.

(Α / 2) {(R ₁ + R ₂ ) + (I ₁ + I ₂ )} + (β / 2) {(R ₁ -R ₂ ) + (I ₁ -I ₂ )}, ( α / 2) {(R ₄ + R ₃ ) + (I ₄ + I ₃ )} + (β / 2) {(R ₄ -R ₃ ) + (I ₄ -I ₃ )}, (α / 2) {(R ₅ + R ₆ ) + (I ₅ + I ₆ )} + (β / 2) {(R ₅ -R ₆ ) + (I ₅ -I ₆ )}, (α / 2) {(R ₈ + R ₇ ) + (I ₈ + I ₇ )} + (β / 2) {(R ₈ -R ₇ ) + (I ₈ -I ₇ )}, (11) For the second antenna 4 b , (10), (1.-
When the averaging unit 16b multiplies the repetition pattern of (1, -1, 1) and performs the averaging process for the adjacent symbols, the second temporary symbol information 1 shown in Expression (12) is obtained.
7b is obtained.

(Β / 2) {(R ₁ + R ₂ ) + (I ₁ + I ₂ )} + (α / 2) {(R ₁ -R ₂ ) + (I ₁ -I ₂ )}, ( β / 2) {(R ₄ + R ₃ ) + (I ₄ + I ₃ )} + (α / 2) {(R ₄ -R ₃ ) + (I ₄ -I ₃ )}, (β / 2) {(R ₅ + R ₆ ) + (I ₅ + I ₆ )} + (α / 2) {(R ₅ -R ₆ ) + (I ₅ -I ₆ )}, (β / 2) {(R ₈ + R ₇ ) + (I ₈ + I ₇ )} + (α / 2) {(R ₈ -R ₇ ) + (I ₈ -I ₇ )}, (12) The symbol information 17a and 17b are used. The signal calculators 18a and 18b calculate the desired signal power Sa and Sb and the interference signal power Ia for each of the first and second antennas 4a and 4b.
Calculate Ib. The signal calculation units 18a and 18b use the following equations (13), (14), (15a) and (15b) to eliminate the influence of quadrant movement and rotation on complex coordinates of each symbol. Calculate the temporary mean and temporary variance.

Here, P and σ ² are (N + 1) after despreading.
These are the sum of squares and the variance of the in-phase component and the quadrature component when the sum and difference between adjacent symbols are obtained in the number of symbols.

[0053] P = (1 / N) [ | A 1 + A 0 | 2/2 + | A 2 + A 1 | 2/2 + | A 3 + A 2 | 2/2 + | A 4 + A 3 | 2 / 2 +, ..., | A N + A N-1 | 2/2] ... (13) σ 2 = (1 / N) [| A 1 -A 0 | 2/2 + | A 2 -A 1 | 2 / ^{_{2+ | A 3 -A 2 | 2}} /2 + | A 4 -A 3 | 2/2 +, ..., | A N -A N-1 | 2/2] ... (14) S = (P-σ 2) / 2 (15a) I = 2σ ² (15b) Using these equations, the first antenna 4 shown in the equation (11)
a in the first provisional symbol information 17a for a
Ask for ² .

Σ ² = (1 / 2N) [| (α / 2) {(R ₄ + R ₃ ) + (I ₄ + I ₃ )} + (β / 2) {(R ₄ -R ₃ ) + (I ₄ -I ₃ )}-(α / 2) {(R ₁ + R ₂ ) + (I ₁ + I ₂ )} + (β / 2) {(R ₁ -R ₂ ) + (I _1- I ₂ )} | ² + | (α / 2) {(R ₈ + R ₇ ) + (I ₈ + I ₇ )} + (β / 2) {(R ₈ -R ₇ ) + (I ₈ -I ₇ )} ― (α / 2) {(R ₅ + R ₆ ) + (I ₅ + I ₆ )} + (β / 2) {(R ₅ -R ₆ ) + (I ₅ -I ₆ )} | ^{2 + ...] = (1 /} 2N) [| (α / 2) {(R 4 + R 3 -R 2 -R 1 + I 4 + I 3 -I 2 -I 1)} + (β / 2) {(R ₄ + R ₂ -R ₃ -R ₁ + I ₄ + I ₂ + I ₃ + I ₁ ) | ² + | (α / 2) {(R ₈ + R ₇ -R ₆ -R ₅ + I ₈ + I ₇ -I ₆ -I ₅ )} + (β / 2) {(R ₈ + R ₆ -R ₇ -R ₅ + I ₈ + I ₆ + I ₇ + I ₅ ) | ² + ...]… (16) Here, assuming that the desired wave Rn is constant for each symbol, the term of the desired wave Rn is deleted from the equation (16), and σ ² ≒ (1 / 2N) [| (α / 2 ) ((I ₄ + I ₃ -I ₂ -I ₁ ) + (β / 2) (I ₄ + I ₂ -I ₃ -I ₁ ) | ² + | (α / 2) ((I ₈ + I ₇ -I ₆ -I ₅ ) + (β / 2) (I ₈ + I ₆ -I ₇ -I ₅ ) | ² + ...] = (１ ／ N) [| (α + β) (I ₄ -I ₁ ) + (α-β) ( I 3 -I 2) | 2 + | (α + β) (I 8 -I ₅ ) + (α-β) (I ₇ -I ₄ ) | ² + ...] (17)

Further, assuming that the interference wave In is normally distributed and the average power for each symbol is constant, all the terms other than the term | In | ² are “0” when the equation (17) is expanded. I thought to converge to, | an in | leaving only ^two sections variance sigma ²
Can be simplified as in equation (18).

Σ ² ≒ (１ ／ N) [(α ² + β ² ) (| I ₁ | ² + | I ₂ | ² + | I ₃ | ² + | I ₄ | ² ) + (α ² + β _{^{2) (| I 5 | 2}} + | I 6 | 2 + | I 7 | 2 + | I 8 | 2) + ...] = (α 2 + β 2) (1 / 8N) [| I 1 | 2 + | I ₂ | ² + | I ₃ | ² +,..., | I _4N | ² ] = (α ² + β ² ) I / 2 (18) A desired wave (common pilot) transmitted from the first antenna 4 a interference wave with respect to the channel) is ^{I = (α 2 + β 2} ) (1 / N) (| I 1 | 2 + | I 2 | 2 + | I 3 | 2 +, ..., | represented by ²⁾ | I _N However, as is apparent from the equation (18), the equation (15b) can be used to calculate Ia = 2σ ² .

Next, the desired signal power S is obtained. The sum of squares P of the in-phase component and the quadrature component is obtained by substituting the numerical value of the expression (11) into the expression (13), and P = (1 / 2N) [| (α / 2) {(R ₄ + R ₃ ) + (I ₄ + I ₃ )} + (β / 2) {(R ₄ -R ₃ ) + (I ₄ -I ₃ )} + (α / 2) {(R ₁ + R ₂ ) + ( I ₁ + I ₂ )} + (β / 2) {(R ₁ -R ₂ ) + (I ₁ -I ₂ )} | ² + | (α / 2) {(R ₈ + R ₇ ) + (I ₈ + I ₇ )} + (β / 2) {(R ₈ -R ₇ ) + (I ₈ -I ₇ )} + (α / 2) {(R ₅ + R ₆ ) + (I ₅ + I ₆ )} + (β / 2) {(R ₅ -R ₆ ) + (I ₅ -I ₆ )} | ² + ...] P = (1 / 2N) [| (α / 2) (R ₄ + R ₃ + R ₂ + R ₁ + I ₄ + I ₃ -I ₂ -I ₁ ) + (β / 2) (R ₄ -R ₃ -R ₂ + R ₁ + I ₄ -I ₃ --I ₂ + I ₁ ^{) | 2 + | (α /} 2) (R 8 + R 7 + R 6 + R 5 + I 8 + I 7 -I 6 -I 5) + (β / 2) (R 8 -R 7 -R 6 + R ₅ + I ₈ -I ₇ --I ₆ -I ₅ ) | ² + ...] (19) Here, the desired wave Rn is a constant average value R for each symbol.
Assuming that we have _AV , equation (19) is further simplified,
Equation (20) is obtained.

[0058] P = (1 / 2N) [ | (α / 2) (4R AV) + (α / 2) (I 4 + I 2 -I 3 -I 1) + (β / 2) {I 4 - _{I 3 --I 2 + I 1}} | 2 + | (α / 2) (4R AV) + (α / 2) (I 8 + I 7 -I 6 -I 5) + (β / 2) (I ₈ -I ₇ --I ₆ -I ₅ ) | ² + ...]] (20) In this equation (20), the term of the interference wave In can be treated in the same manner as when the variance σ ² is obtained, and the desired wave Assuming that the product of Rn and the average value R _AV converges to “0”, equation (20) can be expanded as equation (21).

[0059] P = (1 / 2N) ( α 2/4) (16 | R AV | 2) N + (1 / 2N) [(α / 2) (I 4 + I 3 -I 2 -I 1) + (β / 2) {I ₄ -I ₂ --I ₃ -I ₁ } | ² + | (α / 2) (I ₈ + I ₇ -I ₆ -I ₅ ) + (β / 2) (I _{8 -I 6 --I 7 -I 5)} | 2 + ...] = 2α 2 | R AV | 2 + (α 2 + β 2) (1 / 8N) [| I 1 | 2 + | I 2 | 2 + | I ₃ | ² +,..., | I _4N | ² ] = 2α ² S + σ ² (21) Therefore, the desired wave (common pilot channel) transmitted from the first antenna 4a is S = σ ² (1 / N) | R _AV | ² , which can be calculated by using the equation (15a) and Sa = (P−σ ² ) / 2 as is clear from the equation (21).

The interference wave signal power I on the second antenna 4b side
For b = (α ² + β ² ) I and the desired signal power Sb = β ² S, the signal power calculation unit 18b uses the data of the second temporary symbol information 17b expressed by the equation (17) as described above. It is obtained by the same method as in the case of the first antenna 4a described above.

Then, in the combined signal power calculation unit 21, the signal from the first antenna 4a and the second antenna 4a
b, the combined desired signal power Sc of the entire base station 3 that combines the signals from the base station 3 is calculated by the equation (22).
c is calculated by equation (23) as the average value of the interference wave Ia of the signal from the first antenna 4a and the interference wave from the first antenna 4b.

[0062] ^{Sc = (α 2 + β 2} ) | R AV | 2 = Sa + Sb ... (22) Ic = (α 2 + β 2) (1/2) (| I 1 | 2 + | I 2 | 2 + ,..., + | I _N | ² ) = (Ia + Ib) / 2 (23) Then, the calculated desired signal power Sc of the entire base station 3 is calculated.
= (Α ² + β ² ) S and the interference signal power Ic of the entire base station 3 =
(α ² + β ² ) I is calculated.

Next, the desired signal power is calculated from the integrated value of the sum of adjacent symbols, and the interference signal power is calculated from the integrated value of the difference between adjacent symbols (13) (14) ( Equation 15a) will be described.

[0064] P = (1 / N) [ | A 1 + A 0 | 2/2 + | A 2 + A 1 | 2/2 + | A 3 + A 2 | 2/2 + | A 4 + A 3 | 2 / 2 +, ..., | A N + A N-1 | 2/2] ... (13) σ 2 = (1 / N) [| A 1 -A 0 | 2/2 + | A 2 -A 1 | 2 / ^{_{2+ | a 3 -A 2 | 2}} /2 + | a 4 -A 3 | 2/2 +, ..., | a N -A N-1 | 2/2] ... (14) first, the interference signal power I The calculation method will be described. An = Rn
Since it is + In, the equation (14) is transformed into

(Equation 1) Since the desired wave Rn is considered to be constant for each symbol and the interference wave In is considered to be normally distributed, the terms in the third and fifth rows of the equation (24) are basically “0”. , And the term of _n | I _n I _n-1 | in the fourth row also converges to “0”.
Equation (24) is approximately expressed by equation (24).

[0065] ^{σ 2 = (1 / 2N)} [| I 0 | 2 + | I n | 2 +2 (| I 1 | 2 + | I 2 | 2 + | I 3 | 2 +, ..., | I N- ^{_{1 | 2) ≒ (1 /}} 2N) 2 (| I 1 | 2 + | I 2 | 2 + | I 3 | 2 +, ..., | I N | 2) = (1 / N) (| I 1 | _{^{2 + | I 2 | 2 +}} | I 3 | 2 +, ..., | I N | 2) ... (25) this, (25) obtains the interference signal power I regular described above (4) Is equal to That is, it has been proved that the interference wave signal power can be obtained from the integrated value of the difference between adjacent symbols.

Therefore, the interference wave signal power I is obtained by equation (26).

[0067] ^{I = σ 2 = (1 /} N) [| A 1 -A 0 | 2/2 + | A 2 -A 1 | 2/2 + | A 3 -A 2 | 2/2 + | A 4 -A ^{_{3 | 2/2 +, ...}} , | a N -A N-1 | 2/2] ... (26) Next, a calculation method of the desired wave signal power S. An = Rn
+ In, the equation (13) is transformed into

(Equation 2) And the third line is

(Equation 3)

(Equation 4) Becomes

Therefore, the desired signal power P is given by the following equation (14).
Equation (28) and equation (15a) are used to determine the above.

S = (P−σ ² ) / 2 (15a) As described above, the desired signal power is obtained from the integrated value of the sum of adjacent symbols, and interference is obtained from the integrated value of the difference between adjacent symbols. Since the wave signal power is obtained, there is no need to match the quadrants of the despread symbols. Also, even if the symbol rates do not match on the transmitting side and the receiving side and the despread symbol points rotate on the complex plane,
The influence of the interference wave signal power on the calculation result can be prevented.

[0070]

As described above, in the radio service area evaluation apparatus of the present invention, adjacent symbols having different codes are averaged in symbol information of a common pilot channel after spectrum despreading,
The desired signal power and the interference signal power are calculated from the temporary symbol information as new temporary symbol information.

Therefore, the influence of the quadrant on the complex coordinates can be eliminated without being affected by the fluctuation of the signal level of the received signal, and the radio waves from each antenna of the base station employing the transmission diversity are individually evaluated. it can.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of a radio wave service area evaluation device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a method of evaluating a radio service area of a general base station;

FIG. 3 is a diagram showing each channel incorporated in a W-CDMA signal;

FIG. 4 is a diagram showing a relationship between a base station employing transmission diversity and a measuring instrument.

FIG. 5 is a diagram showing a relationship between output signals of respective antennas of a base station employing transmission diversity and received signals of a measuring instrument.

FIG. 6 is a diagram showing a relationship between a signal wave signal and an interference wave signal on a complex coordinate plane.

[Explanation of symbols]

 Reference Signs List 3 base station 4a first antenna 4b second antenna 5, 5a, 5b radio wave 6 W-CDMA signal 7 common pilot channel 12 RF processing unit 13a first correlator 13b second Correlators 14a, 14b: despreading code generators 16a, 16b: averaging processing sections 18a, 18b: signal power calculating section 19: code determining section 21: combined signal power calculating section 22: display control section 23: display

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiromichi Inagaki 301, Koriyama-shi, Fukushima Prefecture, Tohoku Anritsu Co., Ltd. NTT Docomo (72) Inventor Shinichi Mori 2-1-1, Nagatacho, Chiyoda-ku, Tokyo F-term (reference) 5K022 EE01 EE21 EE31 5K059 CC02 DD31 EE02 5K067 AA02 BB04 CC10 CC24 DD44 EE02 EE10 HH21 LL11

Claims (3)

[Claims] A base station (3) having first and second antennas (4a, 4b) and employing transmission diversity receives a W-CDMA signal transmitted to a mobile station and receives the W-CDMA signal. A radio service area evaluation device for providing information for evaluating a radio service area of the base station based on a signal level, wherein (A, A, A, A,
This W-CDM is multiplied by the repeated symbol pattern of A).
A spectrum despreading is performed on the A signal, and the first
A first despreading unit (13a) for extracting a predetermined number of continuous first symbol information of a common pilot channel corresponding to the antenna of (a), (A, -A,-)
A, A) multiplied by the symbol pattern
A second despreading unit (13b) for performing spectrum despreading on the DMA signal and extracting a predetermined number of continuous second symbol information of a common pilot channel corresponding to the second antenna; In the obtained first symbol information, an average value of adjacent symbols having different symbols of the symbol pattern of the corresponding second antenna is sequentially calculated, and each of the sequentially calculated average values corresponds to a new corresponding antenna. The first averaging unit (16a) that outputs the first temporary symbol information (17a) to be output and the extracted second symbol information have different signs of the symbol patterns of the corresponding second antennas. An average value of adjacent symbols is sequentially calculated, and each of the sequentially calculated average values is used as a second temporary symbol information corresponding to a new corresponding antenna. A second averaging section (16b) that outputs the signal as (17b); and a radio wave of the first antenna from first temporary symbol information corresponding to the first antenna output from the first averaging section. A first signal power calculator (18a) for calculating a desired wave signal power and an interference wave signal power with respect to the second tentative symbol information corresponding to the second antenna output from the second averaging processing unit A second signal power calculator (18b) for calculating a desired signal power and an interference signal power for the radio wave of the second antenna from each other; and each desired signal calculated by the first and second signal power calculators. A combined signal power calculation unit (2) that receives the signal power and each interference wave signal power and calculates a combined desired signal power and a combined interference signal power corresponding to the entire base station based on the signal power and the interference signal power.
1) A radio wave service area evaluation device comprising: 2. The averaging unit according to claim 1, wherein the determination of the code multiplied by the averaging process between the symbols is performed based on a difference in signal level between the symbols, and the symbols having different codes are averaged. 2. The radio wave service area evaluation device according to 1. 3. The quality of a combination of symbols to be averaged in each of the averaging processing units is compared by comparing and contrasting adjacent averaged symbols of each of the temporary symbol information output from each of the averaging processing units. The radio wave service area evaluation device according to claim 1, further comprising a code judging section (19) for judging.