JP2000312168A - Code division multiplex access base station - Google Patents

Abstract

PROBLEM TO BE SOLVED: To process a signal, having long delay time with the circuit constitution of a small scale by inversely spreading a data channel signal whose call is set by a random access channel signal, based on the peak reception time of the random access channel(RACH) signal. SOLUTION: A delay profile measuring part 58 detects the peak of an RACH signal received from a reception part 52 and detects the time, when the peak of the RACH signal is received. The delay profile measuring part 58 outputs the detected peak reception time of the RACH signal to a demodulation part 60 through a control part 66. The delay profile measuring part 58 outputs the detected peak reception time of the RACH signal to a delay profile measuring part 62. The demodulation part 60 inputs the plural RACH signals sent from plural users from a reception part 52 and inversely spreads them, based on the detected peak reception time of the RACH signal, which is detected by the delay profile measuring part 58. The demodulation part 60 outputs the RACH signal which is inversely spread and demodulated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a code division multiple access base station. In particular, the present invention relates to a code division multiple access base station capable of processing a signal having a long delay time.

[0002]

2. Description of the Related Art In order to cope with a change in delay time of a received signal, a conventional code division multiple access (CDMA) base station measures a delay profile of a signal transmission line from a received signal. The delay profile is a response of a signal wave transmitted via different transmission paths and received by the base station. Since signal waves travel through different transmission paths,
The waveform of the signal wave changes under the influence of each transmission path. Therefore, the conventional CDMA base station selects a plurality of peaks having an effective power level, and demodulates the received signal by combining the selected peaks.

FIG. 1 shows a configuration of a CDMA base station. C
The DMA base station includes an antenna 10, a receiving unit 12, a RACH
Signal receiving unit 14, DCH signal receiving unit 16, and control unit 2
6. The RACH signal receiving unit 14 has a delay profile measuring unit 18 and a demodulating unit 20. The DCH signal receiving unit 16 includes a delay profile measuring unit 22 and a demodulating unit 2
4

[0004] An antenna 10 receives a spread spectrum modulated random access channel (RACH) signal and a data channel (DCH) signal.

FIG. 2 shows a random access channel (R
ACH) signal and the data channel (DCH) signal
It shows how it is transmitted between the base station and the mobile station. No.
1. To set up a call, a RACH signal is input from the mobile station to the base station. The RACH signal contains information such as the telephone number and registration number of the user of the mobile station. In the example of FIG. 2, the RACH message of the RACH signal is 10 milliseconds in length. The RACH signal indicates that communication has suddenly started,
Sent by a burst transmission that ends abruptly.

Next, a received (ACH) signal is output from the base station to the mobile station. The ACH signal contains information that the base station has approved the mobile station. The mobile station can then initiate a call and send a DCH signal to the base station. The DCH signal is a call signal set by the RACH signal. The DCH signal starts almost at a specified time after the transmission of the ACH signal, and ends at a predetermined time after the transmission of the DCH signal starts. In the example of FIG. 2, each DCH message of the DCH signal is 10
It has a length of milliseconds.

[0007] The RACH signal and the DCH signal are complex signals having two dimensions of I phase and Q phase. The receiving unit 12
The frequency of the RACH signal and the DCH signal are converted from the carrier frequency band to the baseband frequency band, and output to the RACH signal receiving unit 14 and the DCH signal receiving unit 16, respectively. The RACH signal receiving unit 14 receives the RACH signal from the receiving unit 12 to despread the RACH signal.

[0008] The DCH signal receiving section 16 receives the DCH signal from the receiving section 12 in order to despread the DCH signal. The delay profile measuring unit 18 detects a peak of the RACH signal received from the receiving unit 12, and detects a time at which the peak of the RACH signal is received. Next, the delay profile measurement unit 18 outputs the detected peak reception time of the RACH signal to the demodulation unit 20 via the control unit 26. RACH detected by delay profile measuring section 18
The demodulation unit 20 despreads the RACH signal received from the reception unit 12 based on the peak reception time of the signal. Next, demodulation section 20 outputs the despread and demodulated RACH signal.

[0009] The delay profile measuring unit 22 includes:
2, the DCH signal is received, the peak of the DCH signal is detected, and the time when the peak of the DCH signal is received is detected.
Next, the delay profile measuring unit 22 detects the detected DCH
The peak reception time of the signal is transmitted to the demodulation unit 2
Output to 4. The demodulation unit 24 despreads the DCH signal received from the reception unit 12 based on the peak reception time of the DCH signal detected by the delay profile measurement unit 22. Next, the demodulation unit 24 outputs the despread and demodulated D
Outputs the CH signal.

The control unit 26 includes a delay profile measuring unit 1
For 8 and 22, the type of the spreading code for despreading the RACH signal and the DCH signal and the timing for generating the spreading code are set. The control unit 26 further inputs the peak reception time of the RACH signal from the delay profile measurement unit 18 and outputs the same to the demodulation unit 20. Further, the control unit 26
The peak reception time of the DCH signal is input from the delay profile measurement unit 22 and output to the demodulation unit 24.

The delay profile measuring units 18 and 22
By measuring a delay profile having a long delay time, the base station can receive various delay signals transmitted from various places in the cell area of the base station. While a signal is being transmitted, the signal travels on different transmission paths, so that each delay profile has a different delay time. At the same time as measuring the delay profile, the control unit 26 sends the RACH signal and the D signal to the demodulation units 20 and 24.
The peak reception time of the CH signal is notified. Therefore, the demodulation units 20 and 24 have RACHs having various delay times.
Each of the signal and the DCH signal can be despread.

FIG. 3 shows a detailed configuration of the delay profile measuring unit 18. The delay profile measuring unit 18 can measure a delay profile having a long delay time. The delay profile measuring unit 18 includes a RACH signal matched filter 28 and a RACH signal delay profile measuring unit 34. The delay profile measuring section 18 has a plurality of RACH signal matched filters 28 for despreading RACH signals sent from a plurality of users.
For simplicity, only one RACH signal matched filter 28 is shown in FIG. The RACH signal matching filter 28 includes a spreading code generator 30 and a complex correlator 3
2 Complex correlator 32 may include a complex matched filter. RACH signal delay profile measurement unit 34
Has a power level calculation unit 36, a delay time adjustment unit 38, a delay profile averaging unit 40, and a path detection unit 42.

The RACH signal matching filter 28 receives the RACH signal from the receiving unit 12 and despreads the signal. RACH
The signal delay profile measuring unit 34 calculates the despread RA
Detecting the peak reception time of the RACH signal from the CH signal,
The peak reception time of the RACH signal is output to the control unit 26.

The spreading code generator 30 generates a spreading code and outputs it to the complex correlator 32. The complex phase changer 32 uses the spreading code generated by the
Despread the ACH signal. The RACH signal comprises the I phase and the Q
Since the signal is a complex signal having a phase, the signal demodulated by the complex correlator 32 is also a complex signal having an I phase and a Q phase. The power level calculator 36 calculates the absolute values of the I-phase and Q-phase vectors of the demodulated RACH signal in order to obtain the power level of the demodulated RACH signal. By the power level calculation, the two-dimensional data of the demodulated RACH signal having the I phase and the Q phase is converted into one-dimensional data.

The delay time adjusting section 38 adjusts the delay times of a plurality of delay profiles having different delay times to the same delay time. The delay profile averaging unit 40 has a memory for storing a plurality of delay profiles whose delay times have been adjusted. Since the delay profile averaging section 40 accumulates the respective peaks of the plurality of delay profiles as shown in FIG. 4 below, the peak can be separated from noise and interference components.

In this case, it is assumed that the RACH signal is spread-spectrum modulated by a 256-chip spreading code. The delay profile averaging unit 40 generates 51
It has a memory area of 20 words. Here, one chip is equal to four words. 5120 words are obtained by multiplying 256 chips by 5 symbol periods and further multiplying by 4 which is the oversampling number. The path detection unit 42 detects the peak reception time of the RACH signal by detecting the peak of the RACH signal equal to or greater than the threshold.

The delay profile measuring section 22 has the same configuration as the delay profile measuring section 18. The delay profile measurement unit 18 and the delay profile measurement unit 22
Different spreading codes are used for despreading. The spreading code used in the delay profile measuring unit 18 is RAC
The spreading code used for despreading the H signal and used in the delay profile measuring unit 22 is used for despreading the DCH signal. Delay profile measurement unit 18
Similarly, the delay profile measurement unit 22 can measure a delay profile having a long delay time such as a five-symbol period.

FIG. 4 shows an example of a delay profile of a RACH signal output from a plurality of RACH signal matched filters 28. The delay profile is shown with respect to time. Here, the delay profile measurement unit 18 measures the five RACH signal matched filters 28a, 28b, 28c, 2
8d and 28e in parallel. One symbol period is
It has 1024 samples. The delay profile shown in FIG. 4 is transmitted from one mobile station. Since a signal transmitted from a mobile station is transmitted through various transmission paths, the base station receives a delay profile having various delay times.

In FIG. 4, the output of each of the RACH signal matched filters 28a, 28b, 28c, 28d, and 28e has three peaks. One of the three peaks is a direct wave peak, and the remaining two peaks are delayed wave peaks. These three peaks indicate that the RACH signal was transmitted via three paths. The direct wave is transmitted directly from the mobile station to the base station, and the remaining two delayed waves are transmitted indirectly from the mobile station to the base station while being reflected.

The spreading code of the first symbol of the long code is assigned to the RACH signal matched filter 28a. The spreading code of the second symbol of the long code is assigned to the RACH signal matched filter 28b. Similarly, the spreading codes of the third, fourth, and fifth symbols of the long code are used as RACH signal matched filters 28c, 28c, respectively.
d, and 28e. The spreading code is composed of a long code and a short code. The long code is used to distinguish a specific mobile station from a plurality of mobile stations. The long code has a long period of a plurality of symbol periods. Therefore, even if the long codes are the same, the codes are different by changing the timing of generating the codes. Therefore, the long code assigned to the RACH signal matched filter 28a
This is different from the long code assigned to the CH signal matched filter 28b.

By allocating the first symbol of the long code to the RACH signal matched filter 28a for despreading, a first peak appears during the first symbol period. By assigning the second symbol of the long code to the RACH signal matched filter 28b for despreading, a second peak appears during the second symbol period, and so on, for the third, fourth and fifth symbols. Peaks appear during the third, fourth, and fifth symbol periods, respectively. Therefore, the delay profile measuring unit 18 can measure the peak of the RACH signal that appears during the period of five symbols.

Next, the delay time adjusting section 38 delays the first peak by four symbol periods, delays the second peak by three symbol periods, delays the third peak by two symbol periods, and delays the fourth peak by four symbol periods. Is delayed by one symbol period. Therefore, all peaks in the delay profile have the same delay time of four symbol periods. Next, the respective peaks of the five delay profiles are cumulatively added by the delay profile averaging unit 40. That is, the peaks of the direct waves of the respective delay profiles are cumulatively added.
The peaks of the first delayed waves of each delay profile are cumulatively added separately from the peaks of the direct wave and the second delayed wave. The peaks of the second delayed waves of the respective delay profiles are cumulatively added separately from the peaks of the direct wave and the first delayed wave. The delay profile shown under the arrow in FIG. 4 shows the result of accumulating five delay profiles.

[0023]

The conventional delay profile measuring section 22, like the delay profile measuring section 18, has five DCH signal matched filters in parallel in order to measure a delay profile of five symbol periods. . Further, the delay profile averaging unit of the delay profile measuring unit 22 requires a total memory area of 25,600 words to store five delay profiles for five symbol periods. Further, in order to detect a peak from 5120 words of data, all of 5120 words must be searched. The path detector 42 is connected to a digital signal processor (D
SP), the path detection unit 42 must search all of 5120 words in order to detect a peak. Therefore, the path detection unit 42 must process a huge amount of data at high speed. did not become.

Therefore, an object of the present invention is to provide a code division multiple access base station which can solve the above-mentioned problems. This object is achieved by a combination of features described in the independent claims. The dependent claims define further advantageous embodiments of the present invention.

[0025]

According to a first aspect of the present invention, a code division multiple access base station for a mobile communication system using a code division multiple access system is inputted to the base station to set up a call. Receiving a random access channel signal, detecting at least one peak from the random access channel signal, and detecting a time for receiving a peak of the random access channel signal.
A delay profile measurement unit; and a data channel demodulation unit for despreading a data channel signal for which communication is set by the random access channel signal based on a peak reception time of the random access channel signal detected by the first delay profile measurement unit. It is preferable to provide

The code division multiple access base station receives the data channel signal, detects at least one peak from the data channel signal, and receives the peak of the data channel signal based on the peak reception time of the random access channel signal. The data channel demodulation unit may further include a second delay profile measurement unit that detects time, and the data channel demodulation unit may despread the data channel signal based on a peak reception time of the data channel signal detected by the second delay profile measurement unit. preferable.

Further, in the code division multiple access base station, the first delay profile measuring section detects a peak receiving time of the random access channel signal and outputs the detected peak receiving time to the second delay profile measuring section. 1
It is preferable to have a path detection unit. A second delay profile measurement unit having a spreading code generation unit that generates a spreading code for despreading the data channel signal based on a peak reception time of the random access channel signal;
The first path detection unit may supply the peak reception time of the random access channel signal to the spreading code generation unit.

[0028] The second delay profile measuring section calculates the random access channel signal based on the peak reception time.
A spreading code generation unit for generating a spreading code for despreading the data channel signal may be provided. The spread code generation unit may continuously generate a plurality of spread codes each corresponding to each of a plurality of symbol periods of the data channel signal based on the peak reception time of the random access channel signal.

A second delay profile measuring section for despreading a data channel signal having a plurality of symbol periods using a plurality of spreading codes generated by the spreading code generator, and a plurality of despread symbols; A delay profile averaging unit that stores a data channel signal having a period and adds the stored data channel signals having a plurality of symbol periods, and a second path that detects a peak reception time of the data channel signal from the added data channel signal It is preferable to further include a detection unit.

Preferably, the spread code generator starts generating the spread code when the peak of the random access channel signal is received. The delay profile averaging unit may start storing the despread data channel signals of a plurality of symbol periods based on the peak reception time of the random access channel signal.

A method for processing a received signal for a mobile communication system using a code division multiple access scheme according to the first aspect of the present invention comprises the steps of: receiving a random access channel signal to set up a call; Detecting at least one peak from the random access channel signal; detecting a time for receiving the peak of the random access channel signal; and establishing a call by the random access channel signal based on the peak reception time of the random access channel signal. And despreading the set data channel signal.

The above summary of the present invention does not list all of the necessary features of the present invention, and a sub-combination of these features may also be an invention.

[0033]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described through embodiments of the present invention. However, the following embodiments do not limit the claimed invention and have the features described in the embodiments. Not all combinations are essential to the solution of the invention.

FIG. 5 shows the configuration of a CDMA base station according to the present invention. The CDMA base station includes an antenna 50, a receiving unit 52,
It has a RACH signal receiving unit 54, a DCH signal receiving unit 56, and a control unit 66. The RACH signal receiving unit 54 has a delay profile measuring unit 58 and a demodulating unit 60. DC
The H signal receiving section 56 has a delay profile measuring section 62 and a demodulating section 64.

The antenna 50 receives the spread spectrum modulated RACH signal and DCH signal. The RACH signal and the DCH signal are complex signals having two dimensions of I phase and Q phase. The receiving unit 52 converts the frequency of the received signal from the carrier frequency band to the baseband frequency band,
The signals are output to the RACH signal receiving unit 54 and the DCH signal receiving unit 56, respectively. The RACH signal receiving unit 54
In order to despread and demodulate the H signal, a plurality of RACH signals sent from a plurality of users are received. The DCH signal receiving unit 56 receives a plurality of DCH signals sent from a plurality of users in order to despread and demodulate the DCH signal.

The delay profile measuring section 58 includes the receiving section 5
2 to detect the peak of the RACH signal received from
The time at which the peak of the H signal is received is detected. Next, delay profile measurement section 58 outputs the detected peak reception time of the RACH signal to demodulation section 60 via control section 66. Further, delay profile measurement section 58 outputs the detected peak reception time of the RACH signal to delay profile measurement section 62. Based on the peak reception time of the RACH signal detected by the delay profile measurement unit 58, the demodulation unit 60 receives a plurality of RACH signals sent from a plurality of users from the reception unit 52 and despreads them. Next, demodulation section 20 outputs the despread and demodulated RACH signal.

The delay profile measuring section 62 includes the receiving section 5
2, a DCH signal is input to the delay profile measuring unit 5
The peak reception time of the DCH signal is detected based on the peak reception time of the RACH signal input from Step 8. Next, delay profile measurement section 62 outputs the detected peak reception time of the DCH signal to demodulation section 64 via control section 66. Based on the peak reception time of the DCH signal detected by the delay profile measurement unit 62, the demodulation unit 64
Despreads multiple DCH signals sent from multiple users.

The control unit 66 controls the delay profile measurement unit 5
RA sent from multiple users for 8 and 62
The type of the spreading code used to despread the CH signal and the DCH signal and the timing for generating the spreading code are set. Further, the control unit 66 controls the delay profile measurement unit 5
8 and outputs the RACH signal peak reception time to the demodulation unit 60. Further, the control unit 66 inputs the peak reception time of the DCH signal from the delay profile measurement unit 62 and outputs the same to the demodulation unit 64.

FIG. 6 shows a detailed configuration of the delay profile measuring section 58. The delay profile measurement unit 58
It has a CH signal matching filter 68 and a RACH signal delay profile measuring unit 74. Delay profile measurement unit 5
8 includes a plurality of RACH signal matched filters 68 for despreading RACH signals sent from a plurality of users.
Having. For simplicity, only one RACH signal matched filter is shown in FIG. The RACH signal matched filter 68 has a spreading code generator 70 and a complex correlator 72. Complex correlator 72 may include a complex matched filter. The RACH signal delay profile measuring section 74 includes a power level calculating section 76, a delay time adjusting section 7
8, delay profile averaging section 80, and path detection section 82
Having.

The RACH signal matching filter 68 has a RAC
In order to despread the H signal, a RACH signal is input from the receiving unit 52 to be despread, and the despread RACH signal is
The signal is output to the CH signal delay profile measuring section 74. RA
The CH signal delay profile measuring section 74 detects the peak reception time of the RACH signal from the despread RACH signal, and outputs it to the control section 66 and the delay profile measuring section 62.

The spreading code generator 70 generates a spreading code based on the peak reception time of the RACH signal input from the controller 66, and outputs the generated spreading code to the complex correlator 72. Complex phase changer 7
2 despreads the RACH signal input from the receiving unit 52 using the spreading code generated by the spreading code generating unit 70. Since the RACH signal is a complex signal having I and Q phases, the signal demodulated by the complex correlator 72 is also a complex signal having I and Q phases. The power level calculator 76 calculates the absolute values of the I-phase and Q-phase vectors of the demodulated RACH signal in order to obtain the power level of the demodulated RACH signal. The demodulated R having the I-phase and Q-phase two-dimensional data is calculated by the power level calculation.
The ACH signal is converted into a one-dimensional data signal. 2
The method of converting a signal of dimensional data into a signal of one-dimensional data is not limited to the above method, and another method may be used.

The delay time adjusting section 78 adjusts the delay times of a plurality of delay profiles having different delay times to the same delay time. The delay profile averaging unit 80 has a memory for storing a plurality of delay profiles with adjusted delay times. Since the delay profile averaging unit 80 accumulates the respective peaks of the delay profile as shown in FIG. 9 below, the peak of the RACH signal can be separated from noise and interference components. Path detector 82
Detects the peak reception time of the RACH signal by selecting at least one peak of the RACH signal equal to or greater than the threshold from the delay profile averaged by the delay profile averaging unit 80.

FIG. 7 shows a detailed configuration of the delay profile measuring section 62. The delay profile measuring unit 62 has a DC
An H signal matched filter 84 and a DCH signal delay profile measuring unit 90 are provided. Here, the delay profile measuring section 62 has one DCH signal matched filter 84. The DCH signal matching filter 84 includes the spreading code generation unit 8
6 and a complex correlator 88. Complex correlator 88 may include a complex matched filter. The DCH signal delay profile measuring section 90 includes a power level calculating section 91, a delay profile averaging section 92, and a path detecting section 94.

The spreading code generator 86 receives the peak receiving time of the RACH signal from the delay profile measuring unit 58. The spreading code generator 86 is configured to determine the delay profile
8, a spreading code is generated based on the peak reception time of the RACH signal supplied from. That is, the spreading code generator 8
6 generates a spreading code when a peak of the RACH signal is received. Therefore, the delay profile measuring section 62
Is based on the peak reception time of the RACH signal,
Detect the peak reception time of the signal. Here, the delay profile measuring section 58 is directly electrically connected to the delay profile measuring section 62. The peak reception time of the RACH signal is determined by the delay profile measurement unit 5 via the control unit 66.
8 to the delay profile measurement unit 62.

Complex phase changer 88 despreads the DCH signal input from receiving section 52 using the spreading code generated by spreading code generating section 86. Since the DCH signal is a complex signal having I and Q phases, the signal demodulated by the complex correlator 88 is also a complex signal having I and Q phases. The power level calculator 91 outputs the demodulated DCH
To obtain the power level of the signal, the absolute values of the I-phase and Q-phase vectors of the demodulated DCH signal are calculated. By the power level operation, the demodulated DCH signal having the I-phase and Q-phase two-dimensional data is converted into one-dimensional data. The method of converting a signal of two-dimensional data into a signal of one-dimensional data is not limited to the above method, and another method may be used.

The delay profile averaging section 92 has a memory for storing the delay profile of the DCH signal. The delay profile averaging unit 92 accumulates the respective peaks of the delay profile as shown in FIG. The path detection unit 94 selects at least one peak equal to or larger than the threshold from the delay profile averaged by the delay profile
Detect the peak reception time of the signal.

FIG. 8 shows a RACH signal matched filter 68.
7 shows examples of delay profiles output from a, 68b, 68c, 68d, and 68e. FIG. 8 shows a delay profile of 10 symbol periods. Here, the delay profile measuring unit 58 has five RACH signal matched filters 68a, 68b, 68c, 68d, and 68e in parallel. The signal waves transmitted via the two paths, one direct wave and one delayed wave, are shown in FIG.

First, a direct wave of the RACH signal is input to the antenna 50. Direct waves are from code 1 to code 1
The spread spectrum is modulated by a spreading code of 0.
That is, each of the spreading codes of code 1 to code 10 is multiplied by each of the RACH signals of a plurality of signal periods. For example, a RACH signal of a first symbol period is multiplied by code 1, and a RACH signal of a second symbol period is multiplied by code 2. Thus, the RACH of each symbol period
The signal is spread spectrum modulated with different spreading codes. Each code has a time length of one symbol period. Next, the delayed wave is input to the antenna 50 with a slight delay time from the direct wave. Like the direct wave, the delayed wave is also spread spectrum modulated by the spread codes of code 1 to code 10.

Next, the direct wave and the delayed wave are converted into RACH signal matched filters 68a, 68b, 68c, 68d, and 6
8e is despread. Codes 1 and 6
Is supplied to the RACH signal matched filter 68a. Codes 2 and 7 are provided to a RACH signal matched filter 68b. Codes 3 and 8 are provided to a RACH signal matched filter 68c. Codes 4 and 9 are provided to a RACH signal matched filter 68d. Codes 5 and 10
Is supplied to the RACH signal matched filter 68e. Next, the RACH signal matched filter 68a despreads each of the direct wave and the delayed wave using the code 1 and the code 6. Therefore, a set of the direct wave and the delayed wave despread by the code 1 appears in the first symbol period.
Next, a set of the direct wave and the delayed wave despread by the code 6 appears in the sixth symbol period. Since there is a time interval of 5 symbol periods between code 1 and code 6, the set of the direct wave and the delayed wave despread by code 1 and code 6 has a time interval of 5 symbol periods.

Similarly, a set of the direct wave and the delayed wave despread by the codes 2 and 7 appear in the second symbol period and the seventh symbol period. A set of the direct wave and the delayed wave despread by the codes 3 and 8 appears in the third symbol period and the eighth symbol period. A set of the direct wave and the delayed wave despread by the codes 4 and 9 appears in the fourth symbol period and the ninth symbol period. Finally, a set of the direct wave and the delayed wave despread by the codes 5 and 10 appear in the fifth symbol period and the tenth symbol period.

FIG. 9 shows a procedure for averaging the delay profiles shown in FIG. FIG. 9A shows the output of the power level calculator 76. RACH signal matching filter 68
The power levels of the outputs of a, 68b, 68c, 68d, and 68e are calculated by the power level calculation unit 76. The RACH signal has a value of -1 or 1, and the power level calculator 76 calculates the absolute value by calculating the square of the RACH signal. Therefore, the values of all the RACH signals are 1. . Therefore, the output of the power level calculator 76 is power indicating whether the spread code generated by the spread code generator 70 matches the spread code of the transmission signal. When the spread code generated by the spread code generation unit 70 matches the spread code of the transmission signal, a power peak appears in the delay profile.

FIG. 9B shows the output of the delay time adjusting unit 78. R despread by code 1 and code 6
The delay profile of the ACH signal is delayed by four symbol periods. R despread by code 2 and code 7
The delay profile of the ACH signal is delayed by three symbol periods. R despread by code 3 and code 8
The delay profile of the ACH signal is delayed by two symbol periods. R despread by code 4 and code 9
The delay profile of the ACH signal is delayed by one symbol period. Thus, all the delay profiles are the fifth
It is located at the symbol period.

FIGS. 9C and 9D show the output of the delay profile averaging unit 80. FIG. The five delay profiles shown in FIG. 9B are cumulatively added in the same sample period of the same symbol period, and have two peaks of a direct wave and a delayed wave, respectively, as shown in FIG. 9C.
A set of delay profiles is obtained. Next, in the same sample period of each symbol period, each set of peaks is cumulatively added. Therefore, as shown in FIG. 9D, one peak having two peaks of a direct wave and a delayed wave is provided.
A set of delay profiles is obtained. Next, the delay profile measuring section 58 advances the delay profile by four symbol periods, and positions the delay profile in the first symbol period. Finally, the peak reception time of the RACH signal is detected using the added delay profile shown in FIG.

FIG. 10 shows an example of a delay profile of the RACH signal and a delay profile of the DCH signal obtained by using the peak reception time of the RACH signal. Where 5
The delay profile for the symbol period is shown in FIG. As in FIG. 8, the five delay profiles are 5
RACH signal matched filters 68a, 68b, 68
Output from c, 68d, and 68e. The first delay profile of the RACH signal is input to the RACH signal matched filter 68a with the delay time shown in FIG. Here, the DCH signal matching filter 84
Based on the peak reception time of the H signal, the generation timing of the spread code is shifted by the delay time of the output of the RACH signal matched filter 68a. Therefore, the DCH signal matched filter 84 starts despreading the DCH signal at the new measurement start time.

The spreading codes of code 1 to code 5 are DC
Generated continuously by the H signal matched filter 84.
Here, codes 1 to 5 of the DCH signal are RAC
Codes 1 to 5 used for the H signal are different.
The DCH signal matching filter 84 is a code
Is used to despread the DCH signal.
In one symbol period, two peaks appear.
Next, the power level of each delay profile is
The power level is calculated by the power level calculator 91. Next, the delay profile averaging section 92 accumulates peaks in the same sample period of each symbol period. Therefore, the peaks of the direct waves are cumulatively added to each other, and the peaks of the delayed waves are cumulatively added to each other separately from the peaks of the direct wave. Thus, a delay profile having two peaks of a direct wave and a delayed wave shown on the right side of the arrow in FIG. 10 is obtained.

In the case of delay profile measuring section 58, RA
The arrival time of the CH signal is unknown. For example, FIG. 8 shows an example in which a direct wave despread by code 1 is first input to a base station. However, it is usually unknown which signal is input first to the base station. Therefore, delay profile measuring section 58 has five RACH signal matched filters 68, so it is necessary to wait for a RACH signal having the same spreading code as that of delay profile measuring section 58 for five symbol periods.

Unlike the above-described delay profile measuring section 58, the delay profile measuring section 62 uses the peak reception time of the RACH signal, so that the delay profile measuring section 62 can know which DCH signal arrives. . Therefore, the delay profile measuring section 62 calculates the D value spread with the spreading code that matches the spreading code of the matched filter.
There is no need to have multiple matched filters to wait for the CH signal. Furthermore, since the delay profile averaging unit 92 only needs to store the data output from one DCH signal matched filter 84, the amount of data to be stored can be reduced. As a result, the delay profile averaging unit 92
The size of the memory in the can be reduced.

Further, in the delay profile measuring section 62, D
Since there is only one CH signal matching filter 84, the delay time adjusting unit is not required in the DCH signal delay profile measuring unit 90. For example, the DCH signal matched filter 84 searches for a peak reception time of the DCH signal from a time domain within a half symbol period around the peak reception time of the RACH signal.

Assuming that the memory capacity required for the delay profile averaging section 92 is 1024 words, the memory capacity required for the conventional delay profile averaging section 40 is 5120
Is a word. Therefore, the delay profile averaging unit 9
2 can greatly reduce the required memory capacity. Further, since the delay profile measuring section 62 does not require a delay time adjusting section, the configuration of the delay profile measuring section 62 can be simplified. Further, since the path detector 94 only needs to detect the peak of the DCH signal from the data of 1024 words, the amount of data processed for peak detection can be greatly reduced.

As described above, the present invention has been described using the embodiment. However, the technical scope of the present invention is not limited to the scope described in the above embodiment. It is apparent to those skilled in the art that various changes or improvements can be added to the above embodiment. It is apparent from the description of the appended claims that embodiments with such changes or improvements can be included in the technical scope of the present invention.

[0061]

As is apparent from the above description, according to the present invention, a signal having a long delay time can be processed by a code division multiple access base station having a small circuit configuration.

[Brief description of the drawings]

FIG. 1 shows a configuration of a CDMA base station.

FIG. 2 shows how a RACH signal and a DCH signal are transmitted between a base station and a mobile station.

FIG. 3 shows a detailed configuration of a delay profile measuring unit 18.

FIG. 4 shows an example of a delay profile of a RACH signal output from a plurality of RACH signal matched filters 28.

FIG. 5 shows a configuration of a CDMA base station of the present invention.

FIG. 6 shows a detailed configuration of a delay profile measuring section 58.

FIG. 7 shows a detailed configuration of a delay profile measuring section 62.

FIG. 8 shows RACH signal matched filters 68a, 68b, 6
8 shows examples of delay profiles output from 8c, 68d, and 68e.

FIG. 9 shows a procedure for averaging the delay profiles shown in FIG. 8;

FIG. 10 shows a delay profile and RAC of a RACH signal.
7 shows an example of a delay profile of a DCH signal obtained using the peak reception time of an H signal.

[Explanation of symbols]

 10, 50 ... antenna 12, 52 ... receiving unit 14, 54 ... RACH signal receiving unit 16, 56 ... DCH signal receiving unit 18, 22, 58, 62 ... delay profile measuring unit 20 , 24, 60, 64 ... demodulation units 26, 66 ... control unit 28 ... control units 28, 68 ... RACH signal matched filters 30, 70, 86 ... spreading code generation units 32, 72 , 88 ... complex correlator 34, 74 ... RACH signal delay profile measurement unit 36, 76, 91 ... power level calculation unit 38, 78 ... delay time adjustment unit 40, 80, 92 ... Delay profile averaging unit 42, 82, 94 Path detection unit 84 DCH signal matched filter 90 DCH signal delay profile measurement unit

Claims (10)

[Claims] 1. A base station for a code division multiple access base station for a mobile communication system using a code division multiple access system, the base station receiving a random access channel signal input to the base station for setting up a call. A first delay profile measuring unit for detecting at least one peak from the random access channel signal and detecting a time for receiving the peak of the random access channel signal; and the random access detected by the first delay profile measuring unit. A code channel multiple access base station comprising: a data channel demodulation unit for despreading a data channel signal in which the call is set by the random access channel signal based on the peak reception time of the channel signal. 2. Receiving the data channel signal, detecting at least one peak from the data channel signal, and determining a reception time of the peak of the data channel signal based on the peak reception time of the random access channel signal. A second delay profile measuring unit for detecting, wherein the data channel demodulating unit despreads the data channel signal based on the peak reception time of the data channel signal detected by the second delay profile measuring unit. The code division multiple access base station according to claim 1, wherein: 3. The first delay profile measurement unit detects the peak reception time of the random access channel signal, and determines the detected peak reception time as the second reception time.
3. The code division multiple access base station according to claim 2, further comprising a first path detection unit that outputs to the delay profile measurement unit. 4. The apparatus according to claim 1, wherein the second delay profile measuring section has a spreading code generating section for generating a spreading code for despreading the data channel signal based on the peak reception time of the random access channel signal. The code division multiple access base station according to claim 3, wherein the first path detection unit supplies the spreading code generation unit with the peak reception time of the random access channel signal. 5. The apparatus according to claim 1, wherein the second delay profile measuring section has a spreading code generating section for generating a spreading code for despreading the data channel signal based on the peak reception time of the random access channel signal. The code division multiple access base station according to claim 2, wherein: 6. The spread code generation unit, based on the peak reception time of the random access channel signal, continuously generates a plurality of the spread codes each corresponding to each of a plurality of symbol periods of the data channel signal. The code division multiple access base station according to claim 5, wherein the base station is generated. 7. A complex correlator, wherein the second delay profile measuring unit despreads the data channel signals of the plurality of symbol periods using the plurality of spreading codes generated by the spreading code generator. A delay profile averaging unit that stores the despread data channel signals of the plurality of symbol periods, and respectively adds the stored data channel signals of the plurality of symbol periods; and the added data. Second detecting the peak reception time of the data channel signal from the channel signal
7. The code division multiple access base station according to claim 6, further comprising a path detection unit. 8. When the spreading code generator receives the peak of the random access channel signal,
The code division multiple access base station according to claim 5, wherein the generation of the spreading code is started. 9. The delay profile averaging unit starts storing the despread data channel signals of the plurality of symbol periods based on the peak reception time of the random access channel signal. The code division multiple access base station according to claim 7. 10. A method for processing a received signal for a mobile communication system using a code division multiple access method, comprising: receiving a random access channel signal to set up a call; At least one from the signal
Detecting two peaks; detecting a time of receiving the peak of the random access channel signal; and setting the call by the random access channel signal based on the peak reception time of the random access channel signal. Despreading the selected data channel signal.