JP2001267987A - Wireless base station device and wireless communication method - Google Patents

Abstract

(57) [Summary] [Problem] To receive AAA of RACH and A of AICH
AA transmission can be realized, and interference with other stations is reduced. SOLUTION: Instead of calculating a weight using a signal of a preamble part in RACH, a signal of a preamble part of RACH is received in AAA with a plurality of directivity patterns using existing weights. In which a preamble portion is detected and a despread timing is detected using the delay profile. Further, the gist of the present invention is to transmit the control signal in the AICH in AAA with the directivity pattern selected at the time of AAA reception of the signal of the preamble portion of the RACH.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio base station apparatus and a radio communication method used in a digital radio communication system, and in particular, to DS-CDMA (Direct Sequencnc).
R in e-Code Division Multiple Access) system
ACH (Random Access CHannel) adaptive array antenna (hereinafter abbreviated as AAA) reception and AIC
H (Acquisition Indication CHannel) related to AAA transmission.

[0002]

2. Description of the Related Art Conventionally, a random access channel (RACH) is used for transmitting an uplink signal in call origination of a communication terminal such as a mobile station and packet transmission with a small transmission amount. In this RACH, as shown in FIG. 5, for example, a preamble portion having a length of about
After transmitting one or more times, a message portion having a length of, for example, about 10 ms is transmitted.

[0003] The success or failure of reception of the base station in the preamble portion of the RACH is notified to the communication terminal based on the presence or absence of transmission of the downlink AICH. That is, the communication terminal transmits a preamble portion to the base station on the RACH, for example, at the time of calling, and upon receiving the preamble portion, immediately transmits a control signal for confirmation to the communication terminal by AICH. If reception is not possible, transmission of AICH is not performed. AICH corresponding to own preamble part
If is not received within the specified time, the communication terminal generally increases the transmission power and transmits the pull amble portion again. As described above, until the AICH is received, after transmitting the preamble portion a plurality of times, the communication terminal:
The message part is transmitted to the base station by RACH. FIG. 6 shows the transmission / reception timing on the communication terminal side.

In FIG. 6, a predetermined number of uplink access slots, for example, # 0 to # 14, as shown in FIG. 7, are defined. For each access slot, as shown in FIG. Different offsets are given. Which access slot is valid in the cell to which the communication terminal belongs is broadcast on a broadcast channel.
Therefore, the communication terminal considers the offset corresponding to the broadcasted access slot, and sets the RA at that timing.
CH transmission will be performed.

[0005]

SUMMARY OF THE INVENTION RACH and AICH
In order to reduce interference with other stations,
It is desired to introduce transmission / reception using an adaptive array antenna (AAA).
Since the time from reception of the preamble part in H to transmission of the control signal in AICH is short, it is difficult to introduce transmission and reception using AAA.

That is, usually, the base station
The allowable response time from the reception of the signal to the transmission of the AICH (arrival time of the signal of the preamble part + time for determining the pattern of the preamble part + transmission time of the control signal corresponding to the determined pattern) is 1 ms or less. There is a need to. For this reason, it is difficult for the base station apparatus to perform reception weight calculation based on the preamble portion received on the RACH. As a result, it is difficult to apply AAA reception to the reception of the preamble portion on the RACH.

[0007] Therefore, even in a system in which AAA reception is introduced, the base station receives the preamble portion of the RACH omnidirectionally. As described above, when the preamble portion of the RACH is omnidirectionally received,
This preamble portion has a higher required SIR (Signal to Interference Ratio) than other signals received by AAA.
Or Eb / N0 is required. As a result, the communication terminal
It is necessary to increase the transmission power by transmitting the preamble portion on the RACH by the amount required for high quality.

[0008] In order to increase the transmission power, interference with other stations increases. Further, when RACH is frequently used, the power consumption of the communication terminal increases because the transmission power is increased. Further, since it is difficult for the base station to estimate the direction of arrival of the signal of the preamble portion on the RACH for the same reason as described above, it is difficult to perform AAA transmission for the corresponding AICH transmission. Therefore, it is necessary to perform omnidirectional transmission using higher transmission power as compared with the above, and as a result, interference with other stations will increase during transmission of the AICH even on the downlink.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and a radio base station apparatus and a radio base station apparatus capable of realizing AAA reception of RACH and AAA transmission of AICH and reducing interference with other stations. It is intended to provide a communication method.

[0010]

According to the present invention, there is provided a radio base station apparatus comprising: an adaptive array antenna receiving section for receiving a signal from a communication terminal in an adaptive array antenna with a reception directivity pattern obtained in advance; A correlation level detection unit that performs correlation level detection for each pattern,
A configuration is provided that includes a detection unit that detects a known signal portion (preamble portion) of the random access channel signal using the result of the correlation level detection, and detects despread timing of the known signal portion.

According to this configuration, since the reception directivity pattern is formed using the existing reception weight, it is not necessary to newly obtain the reception directivity pattern from the received signal. For this reason, a reception directivity pattern can be formed quickly, and thereby it becomes possible to receive the known signal portion of RACH by AAA. As a result, on the communication terminal side, transmission power can be reduced, and interference with other stations during RACH transmission can be reduced. Also, RA
When the CH is used frequently, the power consumption of the communication terminal can be reduced.

In the radio base station apparatus according to the present invention, in the above-mentioned configuration, the reception directivity pattern classifies each of the communication terminals into groups based on a direction of arrival of a signal from each of the communication terminals, and obtains each of the groups. A configuration that is the obtained directivity pattern is adopted.

According to this configuration, the number of reception directivity patterns can be reduced by using the directivity patterns obtained for each group when the communication terminals are grouped in forming the reception directivity patterns. As a result, the amount of calculation for calculating the reception weight can be reduced. Further, since the number of reception directivity patterns is small, the number of delay profiles to be created can be small, so that the amount of calculation can be reduced.

[0014] The radio base station apparatus of the present invention employs, in the above configuration, a configuration in which a message portion of a random access channel is received by the adaptive array antenna in the reception directivity pattern.

According to this configuration, since the reception directivity pattern of the known signal portion of the RACH is used, it is possible to perform AAA reception even for the message portion of the RACH. As a result, on the communication terminal side, transmission power can be reduced, and interference with other stations during RACH transmission can be reduced.

In the above configuration, the radio base station apparatus of the present invention has a selector for selecting a signal pattern corresponding to a known signal portion of the random access channel signal, and obtains the signal pattern based on the reception directivity pattern. And a transmission unit for transmitting the signal in the transmission directivity pattern obtained.

According to this configuration, the AIC is used by using the reception weight selected when the known signal portion of the RACH is received.
Since H-AAA transmission is performed, the transmission power to the communication terminal can be relatively reduced, and interference with other stations during AICH transmission can be reduced.

In the above configuration, the radio base station apparatus of the present invention employs a configuration in which despreading timing of a known signal portion of a random access channel signal is used as despreading timing of a message portion subsequent to the known signal portion.

According to this configuration, it is possible to use the despreading timing in a specific directivity obtained by AAA receiving the known signal portion of RACH as the timing of AAA reception of the message portion of RACH. .

A communication terminal apparatus according to the present invention performs wireless communication with the wireless base station apparatus having the above configuration. According to this configuration, since the random access channel signal is received by the base station on the AAA side, the communication terminal apparatus can transmit the random access channel signal with relatively small transmission power. As a result, even when the RACH is used frequently, it is possible to reduce the power consumption of the communication terminal.

The communication terminal apparatus of the present invention performs despreading processing on a random access channel signal on a reference signal transmitted by AAA with the same directivity as an AICH signal transmitted by an adaptive array antenna from a radio base station apparatus. Despreading means, and using the output of the despreading means,
A configuration including a channel estimation unit for performing channel estimation of a CH signal and a demodulation unit for demodulating the AICH signal using an output of the channel estimation unit is employed.

[0022] The communication terminal apparatus of the present invention employs a configuration in which the demodulation means is notified from the upper layer that demodulation is performed using the reference signal for channel estimation.

According to these configurations, even when the adaptive array antenna is applied to the received signal, the signal of the channel transmitted by the adaptive array antenna is used as the reference signal by using the spread code of the channel. Can be. As a result, even if the AICH signal is transmitted by the adaptive array antenna, it can be reliably demodulated.

According to the radio communication method of the present invention, an adaptive array antenna receiving step of receiving a signal from a communication terminal with an adaptive array antenna using a reception directivity pattern obtained in advance, and detecting a correlation level for each of the reception directivity patterns. A correlation level detecting step for detecting a known signal portion of the random access channel signal using the delay profile and a despreading timing of the known signal portion.

According to this method, since the reception directivity pattern is formed using the existing reception weight, it is not necessary to newly obtain the reception directivity pattern from the received signal. For this reason, a reception directivity pattern can be formed quickly, and thereby it becomes possible to receive the known signal portion of RACH by AAA. As a result, on the communication terminal side, transmission power can be reduced, and interference with other stations during RACH transmission can be reduced. Also, RA
When the CH is used frequently, the power consumption of the communication terminal can be reduced.

In the wireless communication method according to the present invention, in the above method, a selection step of selecting a signal pattern corresponding to a known signal portion of the random access channel signal, and the signal pattern is obtained based on the reception directivity pattern. A transmitting step of transmitting with the transmission directivity pattern.

According to this method, the AIC is used by using the reception weight selected when the known signal portion of the RACH is received.
Since H-AAA transmission is performed, the transmission power to the communication terminal can be relatively reduced, and interference with other stations during AICH transmission can be reduced.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The gist of the present invention is not to calculate a weight using a known signal portion (preamble portion) in the RACH, but to calculate a known signal portion of the RACH by a plurality of preset directivity patterns. This is to detect the known signal portion and detect the despread timing by receiving the AAA and selecting from the correlation levels for each directivity pattern. This correlation level detection is performed for each directivity pattern by creating a profile (delay profile) from the correlation output and using the delay profile.
In addition, the gist of the present invention is that the AA of the known signal portion of the RACH is
AICH using the directivity pattern selected at the time of A reception
Is to transmit the control signal in AAA.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. (Embodiment 1) In the present embodiment, R is calculated using a plurality of directivity patterns set in advance using existing weights.
A case will be described in which the signal of the preamble portion of the ACH is received by AAA, a delay profile is created for each directivity pattern, and the preamble portion and the despreading timing are detected using the delay profile. In the present embodiment, the number of antennas at the time of AAA reception is set to 3, an existing weight is grouped among a plurality of channels (users) using an uplink signal, and a weight (group) common to the same group is used. Weight) will be described.

Here, for the sake of simplicity, the number of groups (n) for grouping a plurality of channels is set to 2 and the number of channels (k) is also set to 2.

FIG. 1 is a block diagram showing a configuration of a radio base station apparatus according to Embodiment 1 of the present invention.

Uplink signals received via antenna 101 are input to reception RF circuit 102, respectively. In the reception RF circuit 102, the received signal is down-converted. The down-converted signal is A
A / D conversion is performed by the / D converter 103 to be a baseband signal.

The baseband signals are sent to the direction-of-arrival estimation circuit 104, respectively, and the directivity control circuit 1
06. Here, the reception directivity control circuit 106
Are provided for the number of directivity patterns (two) corresponding to the number of groups when a plurality of channels are grouped. In addition, the arrival direction estimation circuits 104 are provided (two) for the number of channels (the number of users).

The direction-of-arrival estimation circuit 104 estimates the direction of arrival with respect to the received signal of each channel (user). The result of estimation of the direction of arrival is calculated by the reception weight calculation circuit 105.
Sent to The reception weight calculation circuit 105 groups the channels based on the direction of arrival of each channel, and calculates the reception weight for each group.

The reception directivity control circuit 106 performs reception AAA processing on the received signal using the reception weight for each group obtained by the reception weight calculation circuit 105, and converts the signal subjected to the reception AAA processing into the reception directivity. Each time it is output to the demodulation circuit 107 and the searcher 108 for RACH preamble. The demodulation circuits 107 are provided for the number of channels (here, two), and the RACH preamble searchers 108 are provided for the number of preamble patterns × the number of timings.

The demodulation circuit 107 performs a despreading process and a RAKE combining process on the received AAA-processed signal to obtain received data 1 and received data k (the number of channels: 2 in this case). That is, the despreading circuit 107a performs despreading processing on the received AAA-processed signal, performs channel estimation using the output of the despreading circuit 107a using the channel estimation circuit 107c, and uses the channel estimation value to perform RAKE combining. RAKE synthesis is performed by the circuit 107b, and RA
The determination unit 107d determines the signal after the KE combination to obtain received data.

The RACH preamble searcher 108 creates a delay profile for each reception directivity, and detects a preamble and a despread timing from the delay profile.

An operation of AAA reception of RACH in the radio base station apparatus having the above configuration will be described. In RACH transmission from a communication terminal, transmission is performed with a configuration as shown in FIG. Then, the communication terminal transmits the preamble portion and the message portion of the RACH to the base station device at the timing shown in FIG.

When the radio base station apparatus according to the present invention receives the preamble portion of the RACH transmitted from the communication terminal, the radio base station apparatus receives the preamble portion using the reception directivity pattern obtained in advance and the reception directivity pattern formed by the existing reception weight. I do.

The reception directivity pattern obtained in advance includes, for example, directivity formed by grouping a plurality of channels (users) using uplink signals and using a common weight (group weight) within the same group. Use a pattern. Specifically, the arrival direction estimation circuit 1
In 04, the direction of arrival is estimated from the signal from each communication terminal of the dedicated physical channel, and the reception weight calculation circuit 105 divides each communication terminal into a plurality of groups 201 to 203 as shown in FIG. Classification (grouping)
Then, the reception weight is calculated for each group. By using the group weight in this way, the number of reception directivity patterns can be reduced, so that the amount of calculation for calculating the reception weight can be reduced.

The reception weight for forming the reception directivity pattern obtained in advance is not limited to the above group weight, and is not particularly limited as long as it is an existing weight. For example, a reception weight of a preset fixed reception directivity pattern may simply be used as an existing weight. For example, the weight of the reception directivity pattern obtained by spatially dividing the reception directivity pattern equally may be used.

The preamble portion of the RACH is received via an antenna 101, down-converted by a reception RF circuit 102, converted to a digital signal by an A / D converter 103, and becomes a baseband signal. This baseband signal is supplied to the multiplier 1 of the reception directivity control circuit 106.
06a, the existing weights (here, group weights) W1, Wn obtained by the reception weight calculation circuit 105
(N: the number of groups). The signals multiplied by these weights are added by the adder 106b. In addition,
The multipliers 106a are provided corresponding to the number of antennas (here, three). In this way, the preamble portion of the RACH is AAA-received with the reception directivity pattern formed by the existing reception weight (group weight).

The AAA received preamble portion of the RACH is sent to the RACH preamble searcher 108. In the RACH preamble searcher 108, a delay profile is created by the detection circuit 1081 for each directivity pattern. In each detection circuit 1081, a correlation operation is performed between the preamble portion of the RACH and the known RACH preamble code by the matched filter 1081a, and a delay profile is generated by the delay profile generation circuit 1081b based on the correlation operation result. The despread timing is obtained from the delay profile created by the delay profile creation circuit 1081b. This despreading timing may be used for demodulating the message (data) portion of the RACH described later.

The delay profile created by the delay profile creation circuit 1081b is a level detection circuit 1081c.
Sent to The level detection circuit 1081c detects the level of the correlation peak from the delay profile, and outputs information on the detected level to the RACH preamble detection circuit 1082.
Output to The RACH preamble detection circuit 1082 detects the RACH preamble based on the result of the level detection. For example, when the detection level in a certain directivity pattern is equal to or more than a set threshold value, RACH
It is determined that the preamble has been received. In preamble detection, channel separation of the same preamble pattern at the same timing is possible in principle if the reception timing is shifted by several chips, but need not be performed in relation to the hardware scale.

As described above, in the radio base station apparatus according to the present embodiment, since the reception directivity pattern is formed using the existing reception weight, it is not necessary to newly obtain the reception directivity pattern from the received signal. . As a result, a reception directivity pattern can be formed quickly, and as a result, RA
The preamble portion of the CH can be received by AAA. As a result, on the communication terminal side, transmission power can be reduced, and interference with other stations during RACH transmission can be reduced. Also, when the RACH is used frequently, the power consumption of the communication terminal can be reduced.

Next, when receiving the RACH message portion, a reception directivity pattern is formed using the reception weight (group weight) when the preamble portion was received, and AAA reception is performed using this reception directivity pattern. In this case, a method of selecting a reception directivity pattern having the best reception state from the reception directivity patterns detected at the time of reception of the preamble portion and receiving with the reception directivity pattern, or a method of receiving the preamble portion And selecting the top several reception directivity patterns having good reception conditions from the detected reception directivity patterns, and synthesizing the signals received with those reception directivity patterns. Here, the reception state can be determined based on the magnitude of the detection level (correlation peak) for each reception directivity pattern.

For demodulation of the RACH message portion, it is also possible to use the despread timing obtained by the RACH preamble searcher 108. That is, the despread timing output from the delay profile creation circuit 1081b of the RACH preamble searcher 108 is used by the despread circuit 107a of the demodulation circuit 107. As a result, the demodulation circuit 107 does not need to detect the despread timing, and the amount of processing can be reduced.

As for the despreading timing, RA
The message portion of the CH may be buffered, a delay profile may be created again using the message portion, and the despread timing may be detected from the delay profile. Searcher 1 for RACH preamble
08, the despread timing obtained by the delay profile generation circuit 1081b and the delay profile are generated again, and the reliability is determined using various parameters by using the despread timing from the delay profile. By using a signal having a higher value as the despreading timing, it is possible to detect the despreading timing with high accuracy.

As described above, the radio base station apparatus according to the present embodiment uses the reception weight selected at the time of receiving the preamble portion of the RACH to convert the message portion to the AAA.
Since reception is performed, the communication terminal side can reduce transmission power even in the RACH message portion, and can reduce interference with other stations during RACH transmission. If the RACH is used frequently,
Power consumption of the communication terminal can be reduced.

(Embodiment 2) In this embodiment, a signal of the preamble portion of the RACH is received in AAA with a plurality of directivity patterns using existing weights, and a delay profile is created for each directivity pattern. A case will be described in which the preamble portion is detected and the despread timing is detected using the delay profile, and the AICH is AAA transmitted using the reception weight selected at the time of receiving the RACH preamble. In the present embodiment,
The number of antennas at the time of AAA reception is set to 3, and as an existing weight, a plurality of channels (users) using uplink signals.
A case in which weights are grouped between groups and a common weight (group weight) is used in the same group will be described.

FIG. 3 is a block diagram showing a configuration of a radio base station apparatus according to Embodiment 2 of the present invention. Note that FIG.
In FIG. 7, the same parts as those in FIG. 1 are denoted by the same reference numerals as in FIG.

The radio base station apparatus shown in FIG. 3 includes a transmission weight calculating circuit 30 for obtaining a transmission weight from a reception weight used for AAA reception of a preamble portion of a RACH.
2 and a transmission directivity control circuit 303 for controlling the transmission directivity of AICH based on the output from the RACH preamble searcher 108.

The operation of the radio base station apparatus having the above configuration will be described. Since the preamble portion of the RACH is AAA-received with a reception directivity pattern formed using existing reception weights, the operation of detecting the RACH preamble and detecting the despread timing is the same as that of the first embodiment. The description is omitted.

The existing reception weight (for example, the group weight in the first embodiment) obtained by reception weight calculation circuit 105 is output to transmission weight calculation circuit 302. The transmission weight calculation circuit 302 calculates the transmission weight using the existing reception weight. FDD (Fr
eucency Division Duplex), when the carrier frequency is different between the uplink and downlink,
It is conceivable to correct the deviation of the directivity of the weight caused by the carrier frequency difference, or to obtain a transmission weight having the same directivity as the characteristic obtained by combining a plurality of reception directivities. Further, the existing reception weight may be used as it is as the transmission weight. This transmission weight is output to the transmission directivity pattern selection circuit 3033 of the transmission directivity control circuit 303.

On the other hand, searcher 1 for RACH preamble
08 is detected by the reception level comparison circuit 3 of the transmission directivity control circuit 303.
031. The reception level comparison circuit 3031 compares the levels for each reception directivity pattern. For example, a predetermined threshold is compared with a level. The comparison result is output to the reception directivity pattern selection circuit 3032.

The reception directivity pattern selection circuit 3032 selects a reception directivity pattern based on the comparison result. For example, the highest one whose level is equal to or higher than the threshold value or the plurality of higher-order ones whose level is equal to or higher than the threshold value are selected as the reception directivity patterns. The information of the selected reception directivity pattern is transmitted to the transmission directivity pattern selection circuit 30.
33.

The transmission directivity pattern selection circuit 3033 selects the optimum transmission directivity pattern from the transmission directivity patterns calculated from the reception directivity patterns based on the information of the selected reception directivity patterns. The transmission weight of the transmission directivity pattern is multiplied by a multiplier 3036.
Output to As a method for selecting a transmission directivity pattern, for example, when one reception directivity pattern is selected, a transmission directivity pattern having the same directivity as that is selected, and a plurality of reception directivity patterns are selected. In such a case, selecting a transmission directivity pattern having directivity obtained by combining them may be mentioned.

R detected by the RACH preamble detecting circuit 1082 of the RACH preamble searcher 108
The information of the ACH preamble is transmitted to the transmission directivity control circuit 30.
3 is transmitted to the transmission timing control circuit 3034. In the transmission timing control circuit 3034, the detected RAC
The transmission timing is determined according to the H preamble. Then, the transmission timing is output to the AICH code pattern selection circuit 3035.

AICH code pattern selection circuit 3035
Selects an AICH code pattern for the RACH preamble detected by the RACH preamble detection circuit 1082, and generates a multiplier 303 at the determined transmission timing.
6 is output.

The multiplier 3036 multiplies the AICH code pattern by the transmission weight of the transmission directivity pattern selected by the transmission directivity pattern selection circuit 3033. The AICH code pattern multiplied by the transmission weight is output to adder 305 and multiplexed with other transmission data 1 to L digitally modulated by modulation circuit 304.

The multiplexed transmission data and the AICH code pattern are converted into analog signals by the D / A converter 306 and sent to the transmission RF circuit 307. Transmission RF circuit 3
At 07, the analog signal is up-converted. This transmission signal is transmitted from the antenna 101 to the communication terminal via the duplexer 301.

The radio base station apparatus according to the present embodiment
Since the AICH AAA transmission is performed using the reception weight selected at the time of receiving the preamble portion of the ACH, the transmission power can be relatively reduced for the communication terminal, and the transmission power to the other station can be reduced during the AICH transmission. Can be reduced.

(Embodiment 3) In this embodiment, a case will be described where an AICH signal transmitted directionally from a base station is received by a communication terminal.

When the AICH signal is not transmitted by the AAA, the channel estimation of the AICH signal in the communication terminal is P
-Use CPICH (Primary-Common Pilot CHannel). This is 3GPP (3rd. Generation Partnership)
Project).

However, when an AICH signal is transmitted by AAA, a reference signal transmitted with the same directivity as the directivity at the time of transmitting the AICH signal is required for channel estimation in the communication terminal. Therefore, in the present embodiment,
A case will be described where a channel estimation is performed using a directionally transmitted reference signal instead of a normal omnidirectional P-CPICH signal in receiving an AAA transmitted AICH signal, and demodulation is performed. Here, S-CP is used as a reference signal.
A case where an ICH (Secondary-CPICH) signal is used will be described.

FIG. 4 is a block diagram showing a configuration of a communication terminal device for performing radio communication with the radio base station device of the present invention.

The downlink AICH signals received via the antenna 401 are input to the reception RF circuit 402, respectively. The AICH signal is transmitted from the base station in AAA with a predetermined directivity. In the reception RF circuit 402, the received AICH signal is down-converted. The down-converted AICH signal is supplied to the A / D converter 403.
A / D converted into a baseband signal.

The baseband signal is sent to despreading circuit 404, where despreading processing is performed using the same spreading code as that used in the base station.
This despread signal (despread signal) is RAKE
The signals are output to the synthesis circuit 406 and the channel estimation circuit 407.

On the other hand, downlink S-CPICH signals received via antenna 401 are input to reception RF circuit 402, respectively. The S-CPICH signal is AIC
AAA transmission is performed from the base station with the same directivity as the H signal. In the receiving RF circuit 402, the received SC
The PICH signal is down-converted. The down-converted S-CPICH signal is supplied to the A / D converter 403.
A / D converted into a baseband signal.

The baseband signal is sent to reference CH despreading circuit 405, and despread by reference CH despreading circuit 405 using the same spreading code as that used in the base station. The despread signal subjected to the despreading process is output to channel estimation circuit 407.

In the channel estimation circuit 407, the S-CPI
The channel estimation of the despread signal of the AICH signal is performed with reference to the despread signal of the CH signal. The channel estimation value obtained by this channel estimation is used as the RAKE combining circuit 406
Is output to The RAKE combining circuit 406 RAKE combines the despread signal of the AICH signal using the channel estimation value output from the channel estimation circuit 407, and
The signal after the E combination is output to determination section 408. Judgment unit 40
In step 8, the signal after RAKE combining is determined and the received data is output.

In the communication terminal having the above-described configuration, reference-required CH despreading circuit 405 switches the spreading code of the reference CH and despreads the received signal depending on whether or not AAA is applied to the received signal. Perform processing.

That is, for a received signal to which AAA is not applied, a P-CP broadcast over the entire cell.
Since the ICH signal is used as a reference signal, despreading is performed using a P-CPICH spreading code. On the other hand, a reception signal to which AAA is applied, for example, AICH in the present invention.
For signals, S-CP transmitted for part of the cell
Since an ICH signal (a signal of a channel transmitted by AAA) is used as a reference signal, despreading processing is performed using a spreading code for S-CPICH.

Use instruction information indicating whether or not AAA is applied, that is, whether or not a signal of a channel transmitted by AAA is used as a reference signal by applying AAA to a received signal (S-CPICH is used as a reference signal for channel estimation). An instruction to perform demodulation using a signal) is sent from the upper layer to the reference CH despreading circuit 405. By this means, when AAA is applied to a received signal, the signal of that channel can be used as a reference signal using the spreading code of the channel transmitted by AAA. As a result, A
Even when the ICH signal is transmitted by AAA, it can be reliably demodulated.

In the present embodiment, the case where the S-CPICH signal is used as the reference signal, that is, the signal of the channel transmitted by AAA with the same directivity as the AICH signal has been described. Is A
A signal of a channel other than the S-CPICH may be used as long as it is a signal of a channel transmitted in AAA with the same directivity as the ICH signal.

The present invention is not limited to the first to third embodiments, but can be implemented with various modifications. For example,
In the first to third embodiments, the case where the number of antennas is 3, the number of channels (the number of users) is 2, and the number of groups when a plurality of users are grouped is 2 has been described. , The present invention relates to the number of antennas, the number of channels,
The same applies to the case where the number of groups is another number.

In the first to third embodiments, the case where a group weight is grouped among a plurality of channels (users) using an uplink signal and a common group weight is used within the same group is used as the existing reception weight. However, the present invention can be similarly applied when an existing reception weight is used.

[0078]

As described above, according to the radio base station apparatus and the radio communication method of the present invention, the signal of the preamble portion of the RACH is AAA-received in a plurality of directivity patterns using existing weights, and A delay profile is created for each characteristic pattern, a preamble portion is detected and a despread timing is detected using the delay profile, and the AA of the signal of the RACH preamble portion is further detected.
Since the control signal in the AICH is transmitted by the AAA in the directivity pattern selected at the time of the A reception, the AAA reception of the RACH and the AAA transmission of the AICH can be realized, and interference with other stations can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a radio base station apparatus according to Embodiment 1 of the present invention.

FIG. 2 is a diagram for explaining a case where directional reception is used for RACH;

FIG. 3 is a block diagram showing a configuration of a radio base station apparatus according to Embodiment 2 of the present invention.

FIG. 4 is a block diagram illustrating a configuration of a communication terminal device that performs wireless communication with the wireless base station device of the present invention.

FIG. 5 is a diagram showing a configuration of RACH transmission.

FIG. 6 is a diagram showing transmission / reception timing of RACH and AICH.

FIG. 7 is a diagram for explaining an access slot;

FIG. 8 is a diagram for explaining an offset of an access slot.

[Explanation of symbols]

 101, 401 Antenna 102, 402 Receiving RF Circuit 103, 403 A / D Converter 104 Arrival Direction Estimation Circuit 105 Receiving Weight Calculation Circuit 106 Receiving Directivity Control Circuit 107 Demodulation Circuit 108 Searcher for RACH Preamble 301 Duplexer 302 Transmission Weight Calculation Circuit 303 Transmission directivity control circuit 304 Modulation circuit 306 D / A converter 307 Transmission RF circuit 404 Despreading circuit 405 Reference CH despreading circuit 406 RAKE combining circuit 407 Channel estimation circuit

Claims (10)

[Claims] 1. An adaptive array antenna receiving means for receiving a signal from a communication terminal with an adaptive array antenna using a reception directivity pattern obtained in advance, and a correlation level detection means for detecting a correlation level for each reception directivity pattern. Detecting means for detecting a known signal portion of a random access channel signal using a result of the correlation level detection, and detecting despreading timing of the known signal portion. . 2. The reception directivity pattern is a directivity pattern obtained by classifying each of the communication terminals into groups based on the arrival direction of a signal from each communication terminal, and obtaining each group. Wireless base station device. 3. The radio base station apparatus according to claim 1, wherein a message portion of the random access channel is received by an adaptive array antenna using the reception directivity pattern. 4. A selecting means for selecting a signal pattern corresponding to a known signal portion of the random access channel signal, and a transmitting means for transmitting the signal pattern with a transmission directivity pattern obtained based on the reception directivity pattern. The radio base station apparatus according to any one of claims 1 to 3, comprising: 5. The radio base station according to claim 1, wherein despreading timing of a known signal portion of the random access channel signal is used as despreading timing of a message portion subsequent to the known signal portion. apparatus. 6. A communication terminal device for performing wireless communication with the wireless base station device according to claim 1. 7. A despreading means for performing a despreading process on a reference signal transmitted by AAA with the same directivity as an AICH signal transmitted by an adaptive array antenna from a radio base station apparatus to a random access channel signal; A communication terminal comprising: a channel estimation unit that performs channel estimation of the AICH signal using an output of a despreading unit; and a demodulation unit that demodulates the AICH signal by using an output of the channel estimation unit. apparatus. 8. The communication terminal apparatus according to claim 7, wherein the demodulation unit receives an instruction from the upper layer to perform demodulation using the reference signal for channel estimation. 9. An adaptive array antenna receiving step of receiving a signal from a communication terminal with an adaptive array antenna using a reception directivity pattern obtained in advance, and a correlation level detection step of detecting a correlation level for each reception directivity pattern. Detecting a known signal portion of the random access channel signal using the result of the correlation level detection, and detecting a despread timing of the known signal portion. 10. A selecting step of selecting a signal pattern corresponding to a known signal portion of the random access channel signal, and a transmitting step of transmitting the signal pattern with a transmission directivity pattern obtained based on the reception directivity pattern. 10. The wireless communication method according to claim 9, comprising: