JP4814759B2 - Line quality measuring device, base station and terminal - Google Patents

Description

  The present invention relates to a channel quality measuring apparatus that can be employed in a radio communication system that performs communication using a radio frame in which a known signal is inserted in advance, and more particularly to a channel quality measuring apparatus having a CNR measuring function. .

  In general, in line quality measurement, received signal strength (RSSI), carrier received power / noise power (CNR), reception error rate (Bit Error Rate), and the like are used as evaluation indicators for line quality. It is used.

  Hereinafter, the operation of the channel quality measurement based on the conventional CNR estimation will be described taking the case of QPSK modulation as an example (see Patent Document 1 below). First, the carrier power is obtained by estimating the received signal point by taking the absolute value of the received symbol data that has undergone quadrature detection and passed through the received waveform shaping filter and established timing synchronization, aggregated in the first quadrant, Estimate by taking its square. Further, the noise power is estimated by obtaining the variance of the received signal with respect to the received signal points obtained by averaging. Then, the CNR is obtained by calculating the ratio from the carrier power and noise power estimated above.

JP 2000-358079 A

  In the above conventional channel quality measurement method, the CNR is estimated by obtaining the average power of demodulated received symbol data and the variance with respect to the average power. However, in an environment where channel distortion due to residual carrier frequency deviation, fading, etc. exists, the received signal point is located in a different symbol error region from the original correct signal point, and the variance for estimating the noise power Cannot be obtained accurately, and the CNR estimation accuracy deteriorates.

  The present invention has been made in view of the above, and provides a channel quality measuring apparatus capable of compensating for stable CNR estimation accuracy even in an environment where residual carrier frequency deviation exists, a fading environment, and a low CNR environment. The purpose is to obtain.

  In order to solve the above-described problems and achieve the object, the channel quality measurement apparatus according to the present invention corrects the phase-modulated received baseband symbol data based on the frequency deviation estimated by the AFC. And a modulation component removal means for removing a modulation component from the corrected received baseband symbol data using a known symbol, and a signal after the modulation component removal is cumulatively added for each known symbol length, and after the cumulative addition Using the carrier power calculation means for calculating the square of the absolute value of the signal and outputting the carrier power and the signal after the modulation component removal, the difference calculation is performed between adjacent symbols and the difference noise component is extracted. Difference calculating means, noise power calculating means for calculating the square of the absolute value of the extracted differential noise component, outputting noise power, and accumulatively adding the noise power; A cumulative addition means for individually cumulatively adding the carrier power and the noise power after the cumulative addition at a predetermined observation time, and a carrier power pair based on the carrier power and the noise power individually cumulatively added by the cumulative addition means. CNR calculating means for calculating a noise power ratio (CNR).

  According to the present invention, it is possible to suppress deterioration in CNR estimation accuracy due to the influence of transmission channel distortion due to residual carrier frequency deviation and fading that cannot be removed by AFC, and to perform stable and highly accurate line quality measurement from low CNR to high CNR. There is an effect that it can be realized.

  Embodiments of a line quality measuring apparatus according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a diagram showing a configuration example of a first embodiment of a line quality measuring apparatus according to the present invention. The line quality measurement apparatus according to the present embodiment uses an AFC unit 100 that estimates a frequency deviation, a frequency correction unit 101 that performs frequency correction based on a frequency correction value estimated by the AFC unit 100, and a known UW pattern. Then, the modulation component removal computing unit 102 that removes the modulation component from the received symbol data of the UW part, the UW pattern output unit 103 that outputs the UW pattern, the cumulative addition computing unit 104 that performs cumulative addition, and the absolute value of the complex number A power calculator 105 that calculates a square, a cumulative addition calculator 106 that performs cumulative addition at a predetermined observation time, a symbol difference calculator 107 that performs a difference calculation at a predetermined symbol interval, and the square of the absolute value of a complex number Power calculator 108, cumulative addition calculator 109 for cumulative addition, and C / N calculation for calculating CNR from carrier power (S) and noise power (N) It is provided with a 110, a.

  In this embodiment, the degradation of CNR estimation accuracy due to the influence of transmission channel distortion due to residual carrier frequency deviation and fading that cannot be removed by AFC is suppressed, and stable and accurate channel quality measurement from low CNR to high CNR is performed. Realize. Also, the channel quality measuring apparatus configured as described above is mounted on, for example, a base station and a terminal device that configure a wireless communication system that performs communication using a wireless frame in which a known signal is inserted in advance.

  FIG. 2 is a diagram showing a configuration example of a radio frame format used in the line quality measuring apparatus according to the present invention. In FIG. 2, 200 is a synchronization word (UW) used for channel quality measurement, and 201 is a data section.

  FIG. 3 is a diagram showing an example of the differential noise power estimation process (107, 108, 109) by the line quality measuring apparatus according to the present invention. In FIG. 3, 300 is a UW symbol data series after modulation component removal, 301 is an adder, 302 is a power calculator that calculates the square of the absolute value of a complex number, and 303 is an adder.

  Hereinafter, the CNR estimation operation of the present embodiment will be described based on FIG. 1, FIG. 2, and FIG. As shown in FIG. 1, the channel quality measuring apparatus according to the present embodiment is subjected to quadrature detection of a phase-modulated received signal from an antenna, and then subjected to waveform shaping by a received waveform shaping filter, symbol timing extraction, and frequency correction. Received baseband symbol data is used as input data. Further, as shown in FIG. 2, the channel quality measurement apparatus according to the present embodiment is premised on estimating a CNR using a known UW pattern inserted in a radio frame.

Here, the number of UWs is M, the radio frame number is m, and the UW part of the received symbol data is r.
Assuming that _k , UW pattern is d _k , and signal amplitude is A, S ′ _m output by the arithmetic processing of the modulation component removal computing unit 102, UW pattern output unit 103, cumulative addition computing unit 104, and power computing unit 105 is Can be represented by the following formula (1). The modulation component of the received symbol data is removed from the UW pattern, and the cumulative addition computing unit 104 performs cumulative addition for the number of UWs, and then converts to power to estimate carrier power.

Next, when the noise signal is n _k and the noise power is σ ² , the modulation component removal computing unit 102, UW pattern output unit 103, symbol difference computing unit 107, power computing unit 108, and cumulative addition computing unit 109 perform arithmetic processing. The differential noise power N ′ _m between predetermined symbols to be output can be expressed by the following equation (2). The differential noise component is obtained by removing the modulation component of the received symbol data from the UW pattern and making a difference between predetermined symbols. After the noise component obtained by the difference is converted into electric power, the cumulative addition calculator 109 performs cumulative addition to calculate the differential noise power N ′ _m .

Here, as an example of the differential noise power calculation, as shown in FIG. 3, the odd number (U ₁ , U ₃ ,..., U _M-1 ) and the even number (U ₂ , U ₄ ,. .., U _M ) are calculated between adjacent symbols (processing of the adder 301), and the result of conversion into power (processing of the power calculator 302) is synthesized (processing of the adder 303).

Next, the cumulative adders 106, while maintaining the signal power _S'm and differential noise power _N'm calculated on a frame-by-frame basis in the memory for a predetermined observation time period P separately cumulatively adding (formula (3 )reference).

  As shown in the above equation (3), the cumulative addition computing unit 106 cumulatively adds the carrier power and the differential noise power individually for a predetermined observation time, and outputs each result to the C / N computing unit 110.

  The C / N computing unit 110 derives the following equation (4) from the above equations (1), (2), and (3) using the carrier power and the differential noise power calculated in the above equation (3). The CNR is obtained by performing the calculation of the equation (4).

  In the present embodiment, the CNR is estimated using the UW part as a known signal. However, the known signal used in the present invention is not limited to UW, and the present invention is not limited to any kind as long as it is a known signal. (For example, preamble, pilot, unique word, etc.) can be used regardless of the pattern.

  As described above, in the channel quality measurement apparatus according to the present embodiment, the noise component is extracted from the difference between adjacent symbols, so that the influence of the carrier frequency deviation included in the extracted noise component can be suppressed to a low level. Therefore, stable line quality measurement can be performed even in an environment where carrier frequency deviation remains.

Embodiment 2. FIG.
FIG. 4 is a diagram showing a configuration example of the second embodiment of the line quality measuring apparatus according to the present invention. The line quality measuring apparatus according to the present embodiment is configured to include a symbol delay unit 400 that delays by a symbol time and a difference calculation unit 401 that performs a difference calculation, instead of the symbol difference calculation unit 107 described above. In addition, about the structure similar to Embodiment 1 mentioned above, the same code | symbol is attached | subjected and the description is abbreviate | omitted. Here, processing different from that of the first embodiment will be described.

  In the first embodiment described above, when the differential noise power is calculated in the symbol difference computing unit 107, the difference between adjacent symbols between the odd number and the even number in the UW portion is calculated to obtain the differential noise power. However, in the second embodiment, a noise component is extracted from the differential data of one symbol using the symbol delay unit 407 and the difference calculator 408, and the noise power is estimated.

For example, when the noise signal is n _k and the noise power is σ ² , the modulation component removal computing unit 102, the UW pattern output unit 103, the symbol delay unit 400, the difference computing unit 401, the power computing unit 108, and the cumulative addition computing unit 109 are operated. The differential noise power N ′ _m between predetermined symbols output by the processing can be expressed by the following equation (5). The modulation component of the received symbol data is removed from the UW pattern, the signal component is removed by making a difference between predetermined symbols, and the noise component is obtained. After the noise component obtained by the difference is converted into electric power, the cumulative addition calculator 109 performs cumulative addition to calculate the differential noise power N ′ _m .

Next, as in the first embodiment, the cumulative addition computing unit 106 accumulates the signal power S ′ _m and the differential noise power N ′ _m calculated for each frame for a predetermined observation time while holding them in the memory. to add. As shown by the above equation (3), the cumulative addition calculator 106 cumulatively adds the carrier power and the differential noise power for a predetermined observation time, and outputs the result to the C / N calculator 110.

  Then, the C / N computing unit 110 uses the carrier power and the differential noise power calculated by the above equation (3) to obtain the following equation (6) from the above equations (1), (3), and (5). The CNR is obtained by performing the calculation of Expression (6).

  As described above, in the present embodiment, since the number of differential noise component samples can be increased as compared with the first embodiment, the noise power estimation accuracy can be increased. As a result, the CNR estimation accuracy can be improved by improving the estimation accuracy of the noise power.

Embodiment 3 FIG.
FIG. 5 is a diagram showing a configuration example of a third embodiment of the line quality measuring apparatus according to the present invention. The line quality measuring apparatus according to the present embodiment is configured to include q symbol delay unit 500 that delays q symbols (1 <q <M) time instead of symbol delay unit 400 of the second embodiment. In addition, about the structure similar to Embodiment 1 or 2 mentioned above, the same code | symbol is attached | subjected and the description is abbreviate | omitted. Here, processing different from the first and second embodiments will be described.

  In the second embodiment described above, one symbol differential noise power is calculated from the symbol delay unit 400 and the difference calculator 401 to obtain the difference noise power. However, in the third embodiment, the q symbol delay unit 500 and the difference calculator are calculated. A noise component is extracted from the difference data of q symbols using 401, and noise power is estimated.

For example, if the noise signal is n _k and the noise power is σ ² , the modulation component removal computing unit 102, UW pattern output unit 103, symbol delay unit 500, difference computing unit 401, power computing unit 108, and cumulative addition computing unit 109 perform computations. The differential noise power N ′ _m between q symbols output in the processing can be expressed by the following equation (7). A differential noise component is obtained by removing the modulation component of the received symbol data from the UW pattern and performing a difference between q symbols. After the noise component obtained by the difference is converted into electric power, the cumulative addition calculator 109 performs cumulative addition to calculate the differential noise power N ′ _m .

Next, as in the first embodiment, the cumulative addition computing unit 106 holds the signal power S ′ _m and the differential noise power N ′ _m calculated in units of frames in the memory as shown in the above equation (3). While accumulating for a predetermined observation time, the result is output to the C / N calculator 110.

  Then, the C / N calculator 110 uses the carrier power and the differential noise power to derive the following expression (8) from the above expressions (1), (3), and (7), and the expression (8) The CNR is obtained by performing an operation.

  As described above, the present embodiment is an extension of the above-described second embodiment, and the noise component is obtained from the difference data of q symbols (1 <q <M) so that the differential symbol interval can be flexibly handled. The noise power is estimated and extracted. With this configuration, the symbol interval at which the difference is performed is not limited to one symbol, and noise components can be extracted from data that has been differentiated at a symbol interval of one symbol or more, and noise power can be estimated. If the noise power is small enough not to be affected by the frequency deviation, CNR estimation can be performed with the same accuracy as in the second embodiment.

Embodiment 4 FIG.
FIG. 6 is a diagram showing a configuration example of a line quality measuring apparatus according to the fourth embodiment of the present invention. The line quality measuring apparatus according to the present embodiment replaces the symbol difference calculator 107, the power calculator 108, and the cumulative addition calculator 109 of the first embodiment with a symbol difference calculator 600- that performs a difference calculation at intervals of one symbol. 1 and a symbol difference calculator 600-2 that performs a difference calculation at two symbol intervals, a difference calculator 600-q that performs a difference calculation at q symbol intervals (1 <q <M), and a square of the absolute value of a complex number Is configured to include a plurality of power calculators 601 that calculate the above and a cumulative addition calculator 602 that performs cumulative addition. In addition, about the structure similar to Embodiment 1, 2, or 3 mentioned above, the same code | symbol is attached | subjected and the description is abbreviate | omitted. Here, processing different from the first, second, and third embodiments will be described.

  In the third embodiment described above, the differential noise power is calculated by calculating the differential noise power at a predetermined symbol interval. However, in the fourth embodiment, a plurality of symbol difference calculators (600-1, 600 having different time intervals) are obtained. -2, ..., 600-q) and a plurality of power calculators 601 corresponding to them individually, and the differential noise power is calculated by combining them with the cumulative addition calculator 602. Estimate noise power.

For example, when the noise signal is n _k and the noise power is σ ² , the modulation component removal computing unit 102, the UW pattern output unit 103, each symbol difference computing unit (600-1, 600-2,..., 600-q), and each The differential noise power N ′ _m output in the calculation processing of the power calculator 601 and the cumulative addition calculator 602 can be expressed by the following equation (9). After the modulation component of the received symbol data is removed from the UW pattern, the differential noise components obtained by the symbol difference calculators of different symbol intervals are converted into electric power, respectively, and then cumulative addition is performed by the cumulative addition calculator 602. The power N ′ _m is calculated.

Next, as in the first embodiment, the cumulative addition computing unit 106 holds the signal power S ′ _m and the differential noise power N ′ _m calculated in units of frames in the memory as shown in the above equation (3). While accumulating for a predetermined observation time, the result is output to the C / N calculator 110.

  The C / N computing unit 110 derives the following equation (10) from the above equations (1), (3), and (9) using the carrier power and the differential noise power calculated in the above equation (3). The CNR is obtained by performing the calculation of the equation (10).

  As described above, in the present embodiment, the number of differential noise component samples is significantly increased by using symbol difference calculators having different symbol intervals as compared with the configurations of the first embodiment, the second embodiment, and the third embodiment. Therefore, the noise power estimation accuracy can be further increased. However, the difference symbol interval needs to be determined within a range not affected by the remaining carrier frequency deviation.

Embodiment 5 FIG.
FIG. 7 is a diagram showing a configuration example of a line quality measuring apparatus according to the fifth embodiment of the present invention. The line quality measuring apparatus according to the present embodiment has a configuration in which a carrier reproducing unit 700 that performs carrier reproduction is added to the configuration of the first embodiment described above. In addition, about the structure similar to Embodiment 1 mentioned above, the same code | symbol is attached | subjected and the description is abbreviate | omitted. Here, processing different from the first to fourth embodiments will be described.

  In the first embodiment described above, received baseband symbol data subjected to waveform shaping, symbol timing extraction, and frequency correction by a received waveform shaping filter after quadrature detection of a phase-modulated received signal from an antenna is input. However, in the fifth embodiment, channel quality estimation is performed using received symbol data after carrier recovery is performed on received symbol data subjected to frequency correction.

  Specifically, the AFC unit 100 estimates the frequency deviation of the received baseband symbol data, the frequency correction unit 101 performs frequency correction based on the frequency deviation estimated by the AFC unit 100, and the carrier reproduction unit 700 Carrier correction processing is performed on the received symbol data after correction, and the modulation component removal computing unit 102 removes the modulation component from the received symbol data after carrier reproduction processing using a known UW pattern.

  As described above, in the channel quality measurement apparatus according to the present embodiment, the CNR can be estimated also for the received symbol data after carrier recovery is performed, as described above. Note that the configuration of the present embodiment can also be applied to the second embodiment, the third embodiment, and the fourth embodiment described above, and as described above, highly accurate CNR estimation can be realized.

Embodiment 6 FIG.
FIG. 8 is a diagram showing a configuration example of a line quality measuring apparatus according to the sixth embodiment of the present invention. The line quality measuring apparatus according to the present embodiment replaces the cumulative addition calculator 106 and the C / N calculator 110 of the first embodiment described above, and a C / N calculator 800 that calculates CNR from carrier power and noise power. And an arithmetic mean arithmetic unit 801 that performs arithmetic mean for a predetermined observation time. In addition, about the structure similar to Embodiment 1 mentioned above, the same code | symbol is attached | subjected and the description is abbreviate | omitted. Here, processing different from the first to fifth embodiments will be described.

  In the above-described first embodiment, the CNR is calculated and output by the C / N calculator 110 after being cumulatively added by the cumulative addition calculator 104 for a predetermined observation time. The CNR is calculated for each radio frame in the C / N calculator 800 without accumulatively adding the carrier power and the differential noise power calculated by the equations (1) and (2). Then, the arithmetic mean computing unit 801 arithmetically averages the CNR value calculated for each radio frame for a predetermined observation time, and then outputs the averaged CNR.

  Thus, in the present embodiment, the CNR is calculated in units of radio frames without accumulatively adding the carrier power and the differential noise power calculated by the above formulas (1) and (2), and the radio frame units The CNR values were arithmetically averaged for a predetermined observation time. This compensates for the CNR estimation accuracy equivalent to that in the first embodiment. Further, since the present embodiment estimates the CNR in units of radio frames, the observation time of the estimated CNR can be freely changed, and a flexible device configuration can be realized.

Embodiment 7 FIG.
FIG. 9 is a diagram showing a configuration example of a seventh embodiment of the line quality measuring apparatus according to the present invention. The line quality measurement apparatus according to the present embodiment is configured to include a weighted average calculation unit 900 that performs weighted average over a predetermined observation time, instead of the arithmetic average calculation unit 801 of the sixth embodiment. In addition, about the structure similar to Embodiment 6 mentioned above, the same code | symbol is attached | subjected and the description is abbreviate | omitted. Here, processing different from the first to sixth embodiments will be described.

  In the sixth embodiment, the estimated CNR calculated by the C / N calculator 800 is arithmetically averaged for a predetermined observation time. However, in the seventh embodiment, the estimated CNR calculated by the C / N calculator 800 is calculated. The weighted average calculation unit 900 performs weighted averaging for a predetermined observation time.

  As described above, in the present embodiment, the estimated CNR calculated by the C / N calculator 800 is weighted and averaged for a predetermined observation time, so that the time is compared with that in the first and sixth embodiments. At the same time, it is suitable for a transmission line whose transmission line condition fluctuates, and it is possible to perform line quality measurement following the fluctuation of the transmission line. For example, according to the speed of the transmission path fluctuation, weights are respectively added to the past estimated CNR and the current estimated CNR, and added and averaged to control the transmission path followability. Further, when there is no transmission path fluctuation, CNR estimation accuracy equivalent to that in the first and sixth embodiments can be compensated.

Embodiment 8 FIG.
FIG. 10 is a diagram showing a configuration example of an embodiment 8 of the line quality measuring apparatus according to the present invention. The line quality measurement apparatus according to the present embodiment is configured to include a moving average calculation unit 1000 that performs moving average over a predetermined observation time, instead of the arithmetic average calculation unit 801 of the sixth embodiment. In addition, about the structure similar to Embodiment 6 or 7 mentioned above, the same code | symbol is attached | subjected and the description is abbreviate | omitted. Here, processing different from the first to seventh embodiments will be described.

  In Embodiment 6 and Embodiment 7 described above, the estimated CNR is arithmetically averaged or weighted average for a predetermined observation time, but in Embodiment 8, the estimated CNR calculated by the C / N calculator 800 is used. The moving average calculation unit 1000 performs a moving average for a predetermined observation time.

  As described above, in this embodiment, the estimated CNR calculated by the C / N calculator 800 is subjected to a moving average for a predetermined observation time. Therefore, it is possible to measure the line quality by following the fluctuation of the transmission path. For example, by setting the average time and the weighting factor in the moving average calculation unit 1000 according to the speed of the transmission path fluctuation, the transmission path followability can be controlled. Further, when there is no transmission path fluctuation, it is possible to compensate for the CNR estimation accuracy equivalent to that of the first embodiment, the sixth embodiment, and the seventh embodiment.

  As described above, the channel quality measurement apparatus according to the present invention is useful in a radio communication system that performs communication using a radio frame in which a known signal is inserted in advance, and in particular, a base station and a terminal apparatus having a CNR measurement function Suitable for

It is a figure which shows the structural example of Embodiment 1 of the channel quality measuring apparatus concerning this invention. It is a figure which shows the example of 1 structure of the radio | wireless frame format used for the channel quality measuring apparatus concerning this invention. It is a figure which shows an example of the difference noise electric power estimation process by the channel quality measuring apparatus concerning this invention. It is a figure which shows the structural example of Embodiment 2 of the channel quality measuring apparatus concerning this invention. It is a figure which shows the structural example of Embodiment 3 of the channel quality measuring apparatus concerning this invention. It is a figure which shows the structural example of Embodiment 4 of the channel quality measuring apparatus concerning this invention. It is a figure which shows the structural example of Embodiment 5 of the line quality measuring apparatus concerning this invention. It is a figure which shows the structural example of Embodiment 6 of the channel quality measuring apparatus concerning this invention. It is a figure which shows the structural example of Embodiment 7 of the channel quality measuring apparatus concerning this invention. It is a figure which shows the structural example of Embodiment 8 of the channel quality measuring apparatus concerning this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 AFC part 101 Frequency correction part 102 Modulation component removal computing unit 103 UW pattern output part 104 Cumulative addition computing unit 105 Power computing unit 106 Cumulative addition computing unit 107 Symbol difference computing unit 108 Power computing unit 109 Cumulative addition computing unit 110 C / N Operation unit 400 Symbol delay unit 401 Difference operation unit 500 q symbol delay unit 600-1, 600-2, 600-q Symbol difference operation unit 601 Power operation unit 602 Cumulative addition operation unit 700 Carrier regeneration unit 800 C / N operation unit 801 Arithmetic average arithmetic unit 900 Weighted average arithmetic unit 1000 Moving average arithmetic unit

Claims (7)

Frequency correction means for correcting phase-modulated received baseband symbol data based on the frequency deviation estimated by AFC;
Modulation component removing means for removing a modulation component from the corrected received baseband symbol data using a known symbol;
A carrier power calculation means for cumulatively adding the signal after the modulation component removal for each known symbol length, calculating the square of the absolute value of the signal after the cumulative addition, and outputting carrier power;
Using the signal after the modulation component removal, difference calculation means for performing a difference calculation at different symbol intervals and extracting a plurality of difference noise components;
Noise power calculation means for calculating a square of an absolute value for each of the extracted differential noise components, outputting a plurality of noise powers, and accumulating and combining the noise powers;
Cumulative addition means for cumulatively adding the carrier power and the combined noise power individually at a predetermined observation time;
CNR calculating means for calculating a carrier power to noise power ratio (CNR) based on the carrier power and noise power individually cumulatively added in the cumulative addition means;
A line quality measuring apparatus comprising: Carrier reproduction means for performing carrier reproduction on the received baseband symbol data corrected by the frequency correction means;
Further comprising
2. The channel quality measuring apparatus according to claim 1, wherein the modulation component removing unit removes the modulation component from the received baseband symbol data after carrier reproduction. Delete the cumulative addition means,
The CNR calculating means calculates a CNR for each radio frame based on carrier power output by the carrier power calculating means and noise power output by the noise power calculating means,
3. The channel quality measuring apparatus according to claim 1, further comprising an arithmetic average of the CNR in units of radio frames output from the CNR calculating means for a predetermined observation time and outputting the result. Delete the cumulative addition means,
The CNR calculating means calculates a CNR for each radio frame based on carrier power output by the carrier power calculating means and noise power output by the noise power calculating means,
3. The channel quality measuring apparatus according to claim 1, further comprising a weighted average of CNRs in units of radio frames output from the CNR calculating means for a predetermined observation time. Delete the cumulative addition means,
The CNR calculating means calculates a CNR for each radio frame based on carrier power output by the carrier power calculating means and noise power output by the noise power calculating means,
3. The channel quality measuring apparatus according to claim 1, further comprising a moving average of the CNR in units of radio frames output by the CNR calculating means for a predetermined observation time and outputting the result. A base station constituting a wireless communication system that performs communication using a wireless frame in which a known signal is inserted in advance,
Base station comprising a channel quality measuring apparatus according to any one of claims 1-5. A terminal that constitutes a wireless communication system that performs communication using a wireless frame in which a known signal is inserted in advance,
Terminal comprising a channel quality measuring apparatus according to any one of claims 1-5.

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