JP2001274726A - Spread spectrum receiver and spread spectrum reception method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spread spectrum receiver that can properly select a signal with a maximum power among multi-path signals, thereby preventing a noise and an interference component from being selected erroneously. SOLUTION: A circuit 103 applies inverse spread processing to received data that are subjected to analog/digital conversion, a circuit 104 measures mean power of data with a number at that point of time every input of the inversely spread data, a circuit 105 selects a data phase with the mean power of a high-degree number sampling at a higher level among a prescribed number of measured mean power values, a circuit 106 obtains a threshold by multiplying a constant G with a ratio of the maximum power obtained from a prescribed number of means power values to a mean power excluding the mean power of the selected phase from a prescribed number of mean power values, a circuit 107 obtains power of data resulting from tracking the inversely spread data, and a circuit 108 uses a phase of the mean power exceeding the threshold among the mean power values of the selected phase and the tracking data power which is larger for a valid phase and feeds back the result, and to apply inverse spread processing to the data with the valid phase.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a base station apparatus in a mobile communication system to which spread spectrum communication is applied, a mobile station apparatus such as a mobile phone, an information terminal apparatus having a mobile phone function and a computer function, and the like. The present invention relates to a spread-spectrum receiving apparatus and a spread-spectrum receiving method suitable for use in the present invention.

[0002]

2. Description of the Related Art In spread-spectrum communication, detecting a path, which is a transmission path of a radio wave, with high accuracy leads to an improvement in the performance of a communication apparatus. However, in mobile communication, noise components may be erroneously detected due to the effects of multipath fading and noise, which has caused deterioration of characteristics.

[0003] As a method for eliminating signals such as noise only,
For example, the contents described in JP-A-10-336072 are known.

In the receiver disclosed in this publication, as shown in FIG.
01, where the spread code replica generation unit 50
2 are used, and the spread modulation signal is despread at L timings.

[0005] The despread signal is transmitted to L demodulators 5
03 is demodulated. Further, the L average signal power measuring units 5
At 04, the average received power of each of the L despread signals is measured.

The measured average received power values are input to a minimum power extraction unit 505 and a maximum power extraction unit 506, where the minimum signal power value and the maximum signal power value at L timings are detected. Is done. FIG. 6 shows the detected minimum signal power value 601 and maximum signal power value 6.
02 is shown.

Next, threshold control units 508 and 509 control the minimum signal power value 601 and the maximum signal power value 602
As shown in FIG. 6, predetermined constants GA and G
By multiplying by B, two thresholds A and B are obtained and output to the path selection timing detection unit 507.

In the path selection timing detecting section 507, as shown by reference numeral 603 in FIG. 6, each average received power value measured by each average signal power measuring section 504 is equal to or more than the threshold value A and the threshold value B. From the above timings, a multipath timing with a large signal power is detected.

A RAKE combining path selector 510 connected to each demodulator 503 according to the detected timing.
After the signals output from the demodulation units 503 are selected, the signals are RAKE-combined by the RAKE combining unit 511.

As described above, it has been shown that two thresholds A and B are provided to eliminate noise components.

[0011]

However, in a conventional device, in a radio wave environment where the interference component is small and the maximum signal level is small, the minimum signal power value detected by the minimum power extraction unit 505 and the maximum power extraction unit 506 is small. And the difference between the maximum signal power value and the maximum signal power value decreases as shown by reference numerals 701 and 702 in FIG. In this case, the minimum signal power value 701
And the constants GA and G multiplied by the maximum signal power value 702
Since B is a fixed value, the threshold value control units 508 and 509
The magnitudes of the two thresholds A and B obtained by the above are reversed as shown in FIG.

As a result, as shown by the reference numeral 703, even the signal having the maximum power value does not exceed the two threshold values A and B, which are the conditions, so that the path where the power exceeding the threshold values A and B is large is large. In some cases, the signal cannot be detected, and the signal having the maximum power value cannot be selected. Therefore, there is a problem that noise and interference components are erroneously selected.

The present invention has been made in view of such a point, and it is possible to appropriately select a signal having a maximum power value from a multipath signal, thereby preventing a noise and an interference component from being erroneously selected. It is an object of the present invention to provide a spread spectrum receiving apparatus and a spread spectrum receiving method which can prevent the spread spectrum receiving apparatus.

[0014]

According to the present invention, there is provided a spread spectrum receiving apparatus, comprising: a despreading means for despreading data obtained by converting an analog signal into a digital signal at a constant sampling interval after reception; and receiving the despread data. Every time
Delay profile measuring means for measuring the average power of the data of the number at that time, searcher means for selecting the data phase of the average power of the high-order several high-level samples from the measured predetermined number of average power, The ratio of the maximum power value obtained from the measured predetermined number of average powers to the average power value obtained by removing the average power of the selected phase from the predetermined number of average powers is multiplied by a constant. Threshold calculation means for obtaining a threshold value, and tracking means for obtaining the power of data obtained by tracking the despread data,
The phase of the larger power of the average power exceeding the threshold value and the power of the tracking data among the average powers of the selected phase is selected as the effective phase, and the despreading means selects the data of the effective phase. And a path selecting means for feeding back such that despreading is performed.

According to this configuration, since the threshold value is obtained from the ratio between the maximum power value and the average power value, even if the difference between the maximum power value and the minimum power value of the received signal is large / small, In the radio wave environment where the interference component is small and the maximum signal level is small, even if the difference between the minimum signal power value and the maximum signal power value becomes small, the signal having the maximum power value is selected. be able to.

In the spread spectrum receiving apparatus according to the present invention, in the above configuration, the data despread by the despreading means is converted into an R signal.
A configuration is provided which includes RAKE receiving means for receiving and demodulating AKE, decoding means for decoding the demodulated data, and error detecting means for detecting an error in the decoded data.

According to this configuration, after appropriately selecting the signal having the maximum power value from the multipath signals, the signal can be properly decoded.

The spread spectrum receiving apparatus according to the present invention, in the above-described configuration, includes a synchronization monitoring means for determining that synchronization is established when known bits included in data demodulated by the RAKE receiving means are correct, and for determining loss of synchronization when the known bits are incorrect. Have,
The searcher means and the path selection means perform reprocessing in the case of the synchronization loss.

According to this configuration, the accuracy of phase detection of the delayed wave can be improved by determining the synchronization state using the known bits of the demodulated data.

The spread spectrum receiving apparatus according to the present invention, in the above-mentioned configuration, further comprises synchronization monitoring means for determining that synchronization is established when the error detection result detected by the error detection means is correct, and determining that synchronization is lost when the error detection result is incorrect. The searcher means and the path selection means perform reprocessing in the case of the synchronization loss.

According to this configuration, the accuracy of the phase detection of the delayed wave can be improved by determining the synchronization state using the error detection result of the decoded data.

In the spread spectrum receiving apparatus according to the present invention, the synchronization is established when both the known bits included in the data demodulated by the RAKE receiving means and the error detection result detected by the error detecting means are correct. A synchronization monitoring unit that determines that synchronization is lost when an error occurs, and the searcher unit and the path selection unit perform reprocessing when the synchronization is lost.

According to this configuration, the accuracy of phase detection of a delayed wave can be improved by determining a synchronization state using known bits of demodulated data and an error detection result.

In the spread spectrum receiving apparatus according to the present invention, when the power value of the delayed wave of the effective phase selected by the path selecting means exceeds a predetermined power value a plurality of times, the effective phase is enabled. While providing rear protection,
If the power value is lower than the predetermined power value by a plurality of times, a configuration is provided which includes a synchronous protection means for performing forward protection to invalidate the effective phase.

According to this configuration, since the backward and forward protection is performed on the phase fed back to the despreading means, the validity / invalidity of the phase is determined.
The accuracy of detecting the delayed wave can be improved.

The spread spectrum receiving apparatus according to the present invention, in the above-mentioned configuration, comprises: a fading estimating means for estimating fading fluctuation by individually observing fluctuations of a predetermined number of average powers from the delay profile measuring means; Path selecting means for judging whether the delayed waves of the fading fluctuations are the same delayed waves or different delayed waves, and when it is determined that they are the same delayed waves, any one of the phases of the same delayed waves is regarded as an effective phase. And the same path determination means for instructing the same.

According to this configuration, the accuracy of path detection can be improved by adaptively determining the same delayed wave from the fading fluctuation.

The mobile station apparatus of the present invention employs a configuration including a spread spectrum receiving apparatus having the same configuration as any of the above.

According to this configuration, in the mobile station device,
The same operation and effect as any of the above can be obtained.

The base station apparatus of the present invention employs a configuration including a spread spectrum receiving apparatus having the same configuration as any of the above.

According to this configuration, in the base station controller, the same operation and effect as any of the above can be obtained.

The mobile communication system of the present invention employs a configuration including the mobile station apparatus or the base station apparatus having the above configuration.

According to this configuration, in the mobile communication system, the same operation and effect as those of the mobile station apparatus or the base station apparatus having the above configuration can be obtained.

According to the spread spectrum receiving method of the present invention, the digitally converted data is despread after reception, and each time the despread data is input, the average power of the data at that time is measured. From the predetermined number of average powers, a data phase of the average power of the high-order several samples having a high level is selected, the maximum power value obtained from the predetermined number of average powers, and the selected power from the predetermined number of average powers are selected. The ratio of the average power value excluding the average power of the phase is multiplied by a constant to obtain a threshold value, the power of data obtained by tracking the despread data is obtained, and the tracking data power is obtained.
Of the average power of the selected phase, the phase of the larger power with the average power exceeding the threshold is set as the effective phase, and the despreading of the data of the effective phase is performed in the despreading. .

According to this method, since the threshold value is obtained from the ratio between the maximum power value and the average power value, even if the difference between the maximum power value and the minimum power value of the received signal is large / small, In the radio wave environment where the interference component is small and the maximum signal level is small, even if the difference between the minimum signal power value and the maximum signal power value becomes small, the signal having the maximum power value is selected. be able to.

[0036]

Embodiments of the present invention will be described below in detail with reference to the drawings.

(Embodiment 1) FIG. 1 is a block diagram showing a configuration of a spread spectrum receiving apparatus according to Embodiment 1 of the present invention.

The spread spectrum receiving apparatus 10 shown in FIG.
Reference numeral 0 is used for a mobile station device such as a mobile phone in a mobile communication system, an information terminal device having a mobile phone function and a computer function, and a base station device performing wireless communication with the mobile station device. , Receiving antenna 101, receiving circuit 102, despreading circuit 103,
Delay profile measuring circuit 104 and searcher circuit 10
5, the threshold value calculation circuit 106, and the tracking circuit 1
07, the path selection circuit 108, and the RAKE reception circuit 10
9, a decoding circuit 110, and an error detection circuit 111.

In such a configuration, the receiving antenna 1
01 is amplified by the receiving circuit 102 and then A / D converted (sampling interval = n / T, 1
/ T = chip speed, n: integer) and the despreading circuit 103
Is despread by correlation detection.

The data after the despreading process is input to the delay profile measuring circuit 104, where the average power of the data is measured. In this measurement, when the first data is input first, the power of the one data is measured, and then, when the second data is input, the power of the first data is added. Average power is measured, then 3
When the first data is input, the average power of the three data combined with the first and second data is measured, and n
The average power of the data is measured.

The average power thus measured is output to the searcher circuit 105 each time the measurement is performed. In the searcher circuit 105, the data phase of the average power of the upper few samples (for example, the upper three samples) having a high level is selected from the predetermined number of average powers, and the selected phase is determined by the threshold value calculation circuit 106 and the path selection circuit. Output to the circuit 108.

In the threshold value calculation circuit 106, a threshold value is obtained as described below according to a predetermined number of average powers from the delay profile measurement circuit 104 and a selected phase from the searcher circuit 105. This threshold value is used to determine the validity / invalidity (desired signal / noise or interference component) of the delayed wave.

First, a maximum power value is determined from a predetermined number of average powers from the delay profile measuring circuit 104, and an average power value excluding the average power of the selected phase in the searcher circuit 105 is determined from the predetermined number of average powers.

Next, the ratio between the obtained maximum power value and the average power value is obtained. Since this ratio is the ratio between the maximum power value and the average power value, even if the difference between the maximum power value and the minimum power value of the received signal is large / small, it is a value that is almost numerically approximated.

Next, a threshold value is obtained by multiplying the ratio by a predetermined constant G.

In the tracking circuit 107, the despread data output from the despreading circuit 103 is tracked, and the power of the tracked data is obtained.

In the path selection circuit 108, the searcher circuit 1
Of the average power of the selected phase at 05, the average power that exceeds the threshold is determined, and this power is compared with the power of the tracked data so that the higher data phase is valid. Selected as the data phase,
This effective phase is output to the despreading circuit 103.

The despreading circuit 103 despreads the delayed wave data corresponding to the effective phase, and the despread data is demodulated by the RAKE receiving circuit 109.
After the demodulated data is decoded by the decoding circuit 110, an error is detected by the error detection circuit 111 to obtain decoded data.

As described above, according to the spread spectrum receiving apparatus of the first embodiment, the despreading circuit 103 despreads the data obtained by converting the analog signal into a digital signal at a constant sampling interval after reception.
In step 04, every time the despread data is input, the average power of the current number of data is measured, and the searcher circuit 105 selects the higher-level number from the measured predetermined number of average powers. The data phase of the average power of the sample is selected, and the threshold calculation circuit 106 calculates the maximum power value obtained from the measured predetermined number of average powers and the average of the selected phase from the predetermined number of average powers. The ratio to the average power value obtained by excluding the power is multiplied by a constant G to obtain a threshold value, and the tracking circuit 107 obtains the power of the data obtained by tracking the despread data. Then, the phase of the larger of the average power exceeding the threshold value and the power of the tracking data among the average powers of the selected phase is selected as the effective phase. The reverse diffusion of the data in the valid phase then, is fed back to be performed Te.

According to this configuration, since the threshold value is obtained from the ratio between the maximum power value and the average power value, even if the difference between the maximum power value and the minimum power value of the received signal is large / small, In the radio wave environment where the interference component is small and the maximum signal level is small, even if the difference between the minimum signal power value and the maximum signal power value becomes small, the signal having the maximum power value is selected. be able to. That is, since the signal having the maximum power value can be properly selected from the multipath signals, it is possible to prevent noise and interference components from being erroneously selected.

(Embodiment 2) FIG. 2 is a block diagram showing a configuration of a spread spectrum receiving apparatus according to Embodiment 2 of the present invention. However, in the second embodiment shown in FIG. 2, portions corresponding to the respective portions of the first embodiment in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.

The spread spectrum receiving apparatus 200 according to the second embodiment shown in FIG. 2 differs from the apparatus 100 according to the first embodiment in that a synchronization monitoring circuit 201 is provided.

The synchronization monitoring circuit 201 has two functions. The first function is to extract a known bit included in the demodulated data output from the rake receiving circuit 109 and store the known bit in a storage table (not shown). By comparing with the known bits stored in the demodulator, it is determined whether the demodulated known bits are correct. If the demodulated known bits are determined to be correct, it is determined that synchronization has been established. And outputs the results of these determinations to the searcher circuit 105 and the path selection circuit 108.

Searcher circuit 105 and path selection circuit 10
In step 8, when the synchronization monitoring circuit 201 determines that synchronization has been lost, it is determined that the currently selected phase is incorrect.
A new phase selection is started. If it is determined that synchronization has been established, it is determined that the currently selected phase is correct, and that phase is maintained.

The second function is to determine whether or not the error detection result from the error detection circuit 111 is correct. If it is determined to be correct, it is determined that synchronization has been established. If it is determined that it is incorrect, it is determined that synchronization has been lost.
5 and to the path selection circuit 108.

Searcher circuit 105 and path selection circuit 10
In step 8, when the synchronization monitoring circuit 201 determines that synchronization has been lost, it is determined that the currently selected phase is incorrect.
A new phase selection is started. If it is determined that synchronization has been established, it is determined that the currently selected phase is correct, and that phase is maintained.

It is also possible to monitor synchronization using both known bits of demodulated data and error detection results.

As described above, according to the spread spectrum receiving apparatus 200 of the second embodiment, the synchronization monitoring circuit 201 determines the synchronization state using the known bits of the demodulated data or the error detection result, thereby detecting the phase of the delayed wave. Accuracy can be improved.

(Embodiment 3) FIG.3 is a block diagram showing a configuration of a spread spectrum receiving apparatus according to Embodiment 3 of the present invention. However, in the third embodiment shown in FIG. 3, portions corresponding to the respective portions of the second embodiment in FIG. 2 are denoted by the same reference numerals, and description thereof will be omitted.

The difference of the spread spectrum receiving apparatus 300 of the third embodiment shown in FIG. 3 from the apparatus 200 of the second embodiment is that a synchronization protection circuit 301 is provided.

The synchronization protection circuit 301 includes the path selection circuit 10
If the power value of the delayed wave of the effective phase selected in 8 exceeds the predetermined power value a plurality of times (for example, three times), the backward protection for validating the effective phase is performed, and the predetermined power value is reduced. If the number is less than a plurality of times (for example, three times), forward protection is performed to invalidate the effective phase.

As described above, according to spread spectrum receiving apparatus 300 of the third embodiment, backward protection and forward protection are performed on the phase fed back to despreading circuit 103, and the validity / invalidity of the phase is determined. Therefore, the accuracy of detecting the delayed wave can be improved.

(Embodiment 4) FIG.6 is a block diagram showing a configuration of a spread spectrum receiving apparatus according to Embodiment 4 of the present invention. However, in the fourth embodiment shown in FIG. 4, portions corresponding to the respective portions of the third embodiment in FIG. 3 are denoted by the same reference numerals, and description thereof will be omitted.

The spread spectrum receiving apparatus 400 according to the fourth embodiment shown in FIG. 4 differs from the apparatus 300 according to the third embodiment in that a fading estimation circuit 401 and an identical path determination circuit 402 are provided.

The fading estimation circuit 401 estimates fading variation by individually observing the variation of a predetermined number of average powers from the delay profile measuring circuit 104, and the same path determination circuit 402 estimates the fading variation. The variable delay wave is determined to be the same delay wave or a different delay wave, and when it is determined to be the same delay wave, the path selection circuit 108 is instructed to regard any one of the same delay waves as a delay wave.

As described above, according to the spread spectrum receiving apparatus 400 of the fourth embodiment, the accuracy of path detection can be improved by adaptively determining the same delayed wave from fading fluctuation.

[0067]

As described above, according to the present invention,
The signal having the maximum power value can be appropriately selected from the multipath signals, thereby preventing erroneous selection of noise and interference components.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a spread spectrum receiving apparatus according to Embodiment 1 of the present invention.

FIG. 2 is a block diagram showing a configuration of a spread spectrum receiving apparatus according to Embodiment 2 of the present invention.

FIG. 3 is a block diagram showing a configuration of a spread spectrum receiving apparatus according to Embodiment 3 of the present invention.

FIG. 4 is a block diagram showing a configuration of a spread spectrum receiving apparatus according to Embodiment 4 of the present invention.

FIG. 5 is a block diagram showing a configuration of a conventional spread spectrum receiving apparatus.

FIG. 6 is a delay wave level diagram in a conventional spread spectrum receiving apparatus.

FIG. 7 is another delay wave level diagram in the conventional spread spectrum receiving apparatus.

[Explanation of symbols]

100, 200, 300, 400 Spread spectrum receiving apparatus 103 Despreading circuit 104 Delay profile measuring circuit 105 Searcher circuit 106 Threshold calculating circuit 107 Tracking circuit 108 Path selecting circuit 109 RAKE receiving circuit 110 Decoding circuit 111 Error detecting circuit 201 Synchronous monitoring Circuit 301 Synchronization protection circuit 401 Fading estimation circuit 402 Same path determination circuit

Continued on the front page F term (reference) 5K022 EE01 EE36 5K047 AA12 BB01 BB05 CC01 DD01 DD02 GG11 GG27 HH11 HH21 KK04 KK16 LL06 MM12 5K067 AA03 AA05 BB04 CC10 DD25 DD42 DD43 DD44 EE02 EE10 HH22H24

Claims (11)

[Claims] 1. A despreading means for despreading data obtained by converting an analog signal into a digital signal at a constant sampling interval after reception, and each time the despread data is inputted,
Delay profile measuring means for measuring the average power of the data of the number at that time, searcher means for selecting the data phase of the average power of the high-order several high-level samples from the measured predetermined number of average power, The ratio of the maximum power value obtained from the measured predetermined number of average powers to the average power value obtained by removing the average power of the selected phase from the predetermined number of average powers is multiplied by a constant. Threshold calculation means for obtaining a threshold value, and tracking means for obtaining the power of data obtained by tracking the despread data,
The phase of the larger power of the average power exceeding the threshold value and the power of the tracking data among the average powers of the selected phase is selected as the effective phase, and the despreading means selects the data of the effective phase. And a path selecting means for performing feedback so that despreading is performed. 2. The data despread by the despreading means is RA
2. The apparatus according to claim 1, further comprising: RAKE receiving means for receiving and demodulating KE, decoding means for decoding the demodulated data, and error detecting means for detecting an error in the decoded data. Spread spectrum receiver. 3. Synchronization monitoring means for determining that synchronization is established when known bits included in data demodulated by the rake receiving means are correct, and determining synchronization loss when the known bits are incorrect, wherein the searcher means and the path selection means comprise: 3. The spread spectrum communication receiving apparatus according to claim 2, wherein re-processing is performed when the synchronization is lost. 4. An apparatus according to claim 1, further comprising: synchronization monitoring means for determining that the synchronization is established when the error detection result detected by the error detection means is correct, and determining that the synchronization is lost when the error detection result is incorrect. 3. The spread spectrum communication receiving apparatus according to claim 2, wherein reprocessing is performed in the case of: 5. When both known bits included in data demodulated by the RAKE receiving means and an error detection result detected by the error detecting means are correct, synchronization is determined; 3. The spread spectrum communication receiving apparatus according to claim 2, further comprising a synchronization monitoring unit, wherein the searcher unit and the path selection unit perform reprocessing when the synchronization is lost. 6. If the power value of the delayed wave of the effective phase selected by the path selecting means exceeds a predetermined power value a plurality of times,
4. A synchronous protection means for performing rear protection for validating the effective phase and performing forward protection for invalidating the valid phase when the power value is lower than a predetermined power value a plurality of times. The spread spectrum receiver according to any one of claims 1 to 5. 7. A fading estimating means for estimating a fading fluctuation by individually observing a fluctuation of a predetermined number of average powers from a delay profile measuring means, and a delay wave of the individually estimated fading fluctuation being the same delay wave. And determining the different delayed waves, and when determining that the delayed waves are the same, the same path determining means for instructing the path selecting means to consider any one of the phases of the same delayed waves as an effective phase. 7. The method according to claim 1, wherein
The spread spectrum receiver according to any one of the above. 8. A mobile station apparatus comprising the spread spectrum receiving apparatus according to claim 1. 9. A base station apparatus comprising the spread spectrum receiving apparatus according to claim 1. 10. A mobile communication system comprising the mobile station device according to claim 8 or the base station device according to claim 9. 11. The digitally converted data after receiving is despread, and each time the despread data is input, the average power of the data at that time is measured, and the measured average power of the predetermined number of average powers is measured. Select the data phase of the average power of the high-order several samples with high levels from the middle, the maximum power value obtained from the predetermined number of average power, and remove the average power of the selected phase from the predetermined number of average power. A threshold is obtained by multiplying the ratio with the average power value by a constant, the power of the data obtained by tracking the despread data is obtained, and the tracking data power and the threshold value of the average power of the selected phase are calculated. A phase of the larger power with the average power exceeding the effective phase, and despreading the data of the effective phase in the despreading. Law.