KR20000034151A - Smart antenna system using parallel searching apparatus - Google Patents

Abstract

PURPOSE: A smart antenna system using a parallel searching apparatus is provided which can transmit/receive a signal to the desired direction of a user without computation by a spatial filtering using an antenna device having a directional property in a base station of CDMA communication system. CONSTITUTION: A smart antenna can transmit/receive a signal to the desired direction of a user without computation by a spatial filtering using directional antenna devices. RAKE receivers(41,42,---,4N) comprises: a switching and combiner(11) outputting by switching and combining a corresponding signal according to the extent of chip delay of an inputted signal from A/D converters(31,32,---,3M); a parallel searcher(14) comprising a number of signal searcher(141,---,14M) searching which antenna device receives a signal having the same spreading code as a desired spreading code of the user by receiving a digital signal received from the A/D converters loudly; a controller(15) controlling the switching and combiner on the basis of the searching result of the parallel searcher; a number of fingers(121,122,---12K) performing a despreading by receiving an output signal from the switching and combiner; and a maximal ratio combiner(13) adding the output signal from the fingers with each path signal power ratio after considering the time delay as to the output signal.

Description

Smart Antenna System Using Parallel Searcher

The present invention relates to a smart antenna system, and more particularly to a smart antenna system using a parallel searcher.

In the current commercial CDMA system, the signal of another user belonging to the base station is treated as interference noise. Therefore, as the number of users sharing the same frequency in one base station increases, the multiple access interference noise increases, thereby increasing the performance of the system as the bit error probability of the received signal increases. Therefore, the current CDMA system limits the number of users belonging to the base station to improve the performance of the system by a certain level (in the case of voice communication, the bit error rate is 10 ^-3 I keep it). In addition, since future broadband CDMA systems must provide multimedia services such as video communications, the bit error rate of the received signal must be further reduced. 10 ^-7 ).

Therefore, in order to satisfy this bit error rate, it is necessary to further limit the number of users served by one base station or reduce the size of the cell. However, reducing the size of the cell causes the problem that more base stations must be added (base station installation costs increase) and handoff occurs too frequently. Therefore, the research on the smart antenna system for providing a high quality multimedia communication service to a large number of users in one base station without reducing the size of the current cell is being actively conducted.

Smart antenna system uses a plurality of array antenna elements to adjust the gain and phase of the signals received at each antenna element, and receives only the signals propagated from the direction of the desired user at the base station and propagates in other directions The noise signal level due to the multiple access interference is greatly reduced, thereby improving the performance of the system and increasing the channel capacity of the base station.

However, in a wireless channel environment, the user's signal is incident as a multipath signal with different time delays and phase delays. Accordingly, the RAKE receiver of the current CDMA base station system detects all of the multipath signals having a reception power higher than a threshold value and performs despreading on a path signal whose time delay coincides with a corresponding finger on a plurality of fingers. Combining this with the ratio of received path signal power has increased system stability and performance.

In general, multipath signals with different time delays are received in different directions. Therefore, in order to apply the smart antenna system to the base station of the CDMA communication method, each finger of the RAKE receiver needs to estimate the direction of the path signal in which the finger coincides with the time delay, and perform spatial filtering to receive the signal only in this direction. do. In addition, in order to perform spatial filtering, a complex weight vector for receiving a signal only in a path direction of a corresponding user must be estimated and multiplied by this vector to all digital data received by each antenna element, which requires a large amount of computation. Therefore, if the actual implementation of such smart antenna system, the price of the system increases and the complexity increases.

For example, if the bandwidth of the signal is 20 MHz and the A / D converter performs oversampling of I channel 4 times and Q channel 4 times as in the current base station system, the data rate of the digital signal received and converted in each antenna element is 20 x 8M chips per second. Multiplying this data by the complex weight vector to perform spatial filtering requires calculation of 20 × 8 × 4M clock / sec (assuming 4 clocks are required for multiplication of complex numbers).

If the number of array antenna elements is 8, all data received from each antenna element must be multiplied by the complex weight vector, so a calculation of 20 × 8 × 4 × 8M clock / sec is required, and the signal with the same time delay at each finger. Since the spatial filtering must be done separately, one user's demodulator requires a total calculation of 20 × 8 × 4 × 8 × 3M clock / sec = 15.36 Gcps (with three fingers). In addition, to estimate the path direction of the signal, a complex weight vector must be obtained. In the above calculation, it is understood that the calculation amount is very large even though this calculation amount is excluded.

Despreading is first performed to reduce the computation by spatial filtering, and the signal can be multiplied by a complex weight vector, but this method increases the complexity of the system because it requires more correlators as multiples of the number of antenna elements. .

Thus, the use of a switched beam antenna system to perform spatial filtering without calculation by spatial filtering may be considered. Switched beam antenna systems receive signals using a plurality of directional antenna elements. The base station of the system determines in which antenna direction the received signal is received the largest and sends a signal from the antenna direction to the demodulator, and the demodulator performs processing on the signal in this direction (CDMA communication method). If you use, despread). If the signal power in this direction falls below the threshold, the base station again searches for the direction in which the signal is received the most and sends a signal from the antenna direction with the largest received power to the demodulator. However, each path signal is received in several directions and sometimes spreads over a fairly wide range (i.e., with a large reception angle dispersion). Therefore, in this case, if the signal is caught only in one antenna direction, a significant portion of the signal of the corresponding user received in the other direction may be lost and the performance of the system may be degraded.

Currently, smart antenna system technology is being studied in three directions to improve the capacity and performance of a system by reducing interference noise caused by a different user received from a different direction from a desired user's signal.

In the first technique, when a multipath signal is received, the finger of the RAKE receiver estimates the direction of a path signal whose time delay coincides, and performs spatial filtering to receive the signal only from this direction. Despreading (US Pat. No. 5,621,752, Title of the Invention; Adaptive sectorization in a spread spectrum communication system and Ayman F. Naguib, "Adaptive Antennas for CDMA Wireless Network", Ph. D. thesis, Stanford University , August 8, 1996).

However, as described above, this method requires too much computation by spatial filtering, so that a very fast DSP chip is required to actually implement it.

In the second technique, as in the first technique, spatial filtering is performed on the finger of the RAKE receiver, but despreading is performed on the finger first, and then spatial filtering is performed. This method reduces the computational complexity due to spatial filtering (about 1 / process gain times compared to the first method), but requires a correlator of as many times as the number of antenna elements (M times when the number of antenna elements is M). Complexity increases.

The third technique is a switched beam antenna system. The switched beam antenna system can receive a directional signal without calculation by spatial filtering by receiving a signal using a plurality of directional antenna elements, but the signal received in any one antenna direction when the signal is widely spread and received By performing despreading with bays, the performance and stability of the system can be degraded. In addition, since this scheme is developed for FDMA and TDMA schemes, there is no detailed description on how to handle each path direction signal having a different time delay and reception angle in the CDMA communication scheme. In the FDMA and TDMA communication methods, demodulation is performed using only one direction signal having the largest signal reception power among several path signals. This is because diffusion is performed.

The present invention has been made in view of the above, and provides a smart antenna system that can transmit and receive signals in the direction of the desired user without calculation by spatial filtering using antenna elements having directivity in the base station of the CDMA communication method Its purpose is.

In addition, the present invention, even when the angular dispersion of the received signal is large (that is, when the user's signal is widely spread and received) by receiving all the signals in the direction of the antenna having a received power above the threshold to perform despreading, Another object is to provide a smart antenna system that improves performance and allows for more stable signal reception.

1A is a diagram illustrating an array antenna element having a linear structure;

Figure 1b is a view showing the array antenna element of a circular structure,

2 is a beam pattern of eight array antenna elements having a linear structure;

3 is a block diagram of a base station for a parallel search smart antenna system using a plurality of directional array antenna elements;

4 is a block diagram of a RAKE receiver using a parallel searcher;

5 is a diagram illustrating a search result of a received signal and a parallel searcher;

6 is a block diagram of a base station for a parallel search smart antenna system using a non-directional array antenna element;

7 is a view illustrating in detail a beamforming unit.

A ₁ , A ₂ , ---, A _M --- directional array antenna element

B ₁ , B ₂ , ---, B _M --- Omnidirectional array antenna element

1 ₁ , 1 ₂ , ---, 1 _M --- low noise amplifier

2 ₁ , 2 ₂ , ---, 2 _M --- downconverter

3 ₁ , 3 ₂ , ---, 3 _M --- A / D converter

4 ₁ , 4 ₂ , ---, 4 _N --- RAKE Receiver

5 ₁ , 5 ₂ , ---, 5 _N --- Judgment

6 ₁ , 6 ₂ , ---, 6 _N --- deinterleaver

7 ₁ , 7 ₂ , ---, 7 _N --- Viterbi decoder

11 --- switching and combiner

12 ₁ , 12 ₂ , ---, 12 _K --- Finger

13 --- Max Non Combiner

14 --- Parallel Explorer

14 ₁ , ---, 14 _M --- Signal searcher

15 --- controller

22 --- beamforming unit

Smart antenna system using a parallel probe according to the present invention for achieving the above object, a plurality of directional array antenna elements; A plurality of low noise amplifiers for amplifying a signal received from the antenna element; A plurality of downconverters for converting the signal amplified by the low noise amplifier into baseband signals of I and Q channel signals; A plurality of A / D converters for converting the signal converted by the downconverter into a digital signal having a data rate higher than that of the system spreading code; A switching and combiner for switching and outputting a corresponding signal according to the degree of chip delay of the signal input from the A / D converter, and a spreading code of a desired user receiving a digital signal received from the A / D converter Parallel searcher consisting of a plurality of signal searchers for searching in which antenna element direction a signal having a spreading code such as a large signal is received, and a controller for controlling the switching and combiner based on the information obtained from the search result of the parallel searcher. And a plurality of fingers for performing despreading upon receiving the output signal from the switching and combiner, and a maximum non-coupler for summing the output signals from the fingers and adding them to the ratio of the received power of each path signal. A plurality of RAKE receiver provided with; A plurality of determiners that receive a signal output from the RAKE receiver and determine whether the digital value is 1 or 0; A deinterleaver for receiving and deinterleaving the output signal from the determiner; A Viterbi decoder that receives an output signal from the deinterleaver and corrects an error; Using the plurality of searchers, the path signal reception power of the user received from each antenna element direction is estimated, and despreading is performed by combining a signal of an antenna direction having a reception power of a threshold or more.

In addition, a smart antenna system using a parallel probe according to the present invention, a plurality of non-directional array antenna elements; A plurality of low noise amplifiers for amplifying a signal received from the antenna element; A plurality of downconverters for converting the signal amplified by the low noise amplifier into baseband signals of I and Q channel signals; A plurality of A / D converters for converting the signal converted by the downconverter into a digital signal having a data rate higher than that of the system spreading code; After receiving the digital signal input from the A / D converter, the digital data is multiplied by the complex weight vector corresponding to the different directions to direct the M output signals as if they were received in the different M directions. A beamforming unit configured to have M signals; A switching and combiner for switching and outputting a corresponding signal according to the degree of chip delay of the signal input from the A / D converter, and a spreading code of a desired user receiving a digital signal received from the A / D converter Parallel searcher consisting of a plurality of signal searchers for searching in which antenna element direction a signal having a spreading code such as a large signal is received, and a controller for controlling the switching and combiner based on the information obtained from the search result of the parallel searcher. And a plurality of fingers for performing despreading upon receiving the output signal from the switching and combiner, and a maximum non-coupler for summing the output signals from the fingers and adding them to the ratio of the received power of each path signal. A plurality of RAKE receiver provided with; A plurality of determiners that receive a signal output from the RAKE receiver and determine whether the digital value is 1 or 0; A deinterleaver for receiving and deinterleaving the output signal from the determiner; A Viterbi decoder that receives an output signal from the deinterleaver and corrects an error; After dividing a cell (or sector) into a plurality of directions, a complex weight vector for each direction is multiplied by a signal received from each antenna element to produce a plurality of signals having a directivity, and then each antenna element using the plurality of searchers. It is characterized in that the path signal reception power of the user received from the direction is estimated, and despreading is performed by combining a signal in the antenna direction having a reception power of more than a threshold value among them.

(Example)

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The base station antenna according to the present invention is composed of a plurality of antenna elements having directivity. Such antenna elements A ₁ , A ₂ , -----, A _M may be arranged in a linear structure as shown in FIG. 1A or may be arranged in a circular structure as shown in FIG. 1B. .

In general, when the antenna elements A ₁ , A ₂ , -----, A _M cover the entire cell, a circular structure is used, and when the cell is divided into three sectors of 120 °, a linear structure is used. I use it. Each antenna element shown in FIGS. 1A and 1B has directivity. For example, when covering one sector having an angle of 120 ° using eight linear array antenna elements, the beam pattern of the directional antenna elements becomes as shown in FIG. At this time, the beam pattern of each directional antenna element overlaps with the beam pattern of the neighboring antenna element.

FIG. 3 is a block diagram of a base station system in which M directional antenna elements are linearly arranged. In the smart antenna system having a plurality of directional array antenna elements as shown in FIG. 3, each array antenna element (A ₁ , A ₂ ,-) is shown. The signal received by _-M is converted to the baseband signal of the I-channel and Q-channel signals, and then the data rate of the system spreading code in the A / D converter (3 ₁ , 3 ₂ , ---, 3 _M ) It is converted to a digital signal having a higher data rate (four times the spread code data rate in current CDMA systems). The I-channel and Q-channel digital signals converted in this way are input to a 2-D RAKE receiver 4 ₁ , 4 ₂ , ---, 4 _N (hereinafter abbreviated as "RAKE receiver").

In a wireless channel environment, a user's signal is received as multiple multipath signals with different time delays, phases, and reception angles. Therefore, the RAKE receivers 4 ₁ , 4 ₂ , ---, 4 _N in the present invention perform despreading in consideration of the time delay and reception angle of these multipath signals.

Figure 4 illustrates in detail the RAKE receiver according to the invention, which comprises a switching and combiner 11, a parallel searcher 14, a controller 15 and a plurality of fingers 12 ₁ , 12 ₂ , --- , 12 _K ), and a maximal ratio combiner (13). Here, the parallel searcher 14 of the RAKE receiver is composed of as many searchers as the number of antenna elements (e.g., M). Each of the searchers 14 ₁ , ---, 14 _M of the parallel searcher 14 receives a digital signal received from the corresponding antenna elements A ₁ , A ₂ , ---, A _M. For example, a signal received from the first antenna A ₁ is input to the first signal searcher 14 ₁ , and a signal received from the second antenna A ₂ is input to the second signal searcher (not _shown ). and, in the M-signal Explorer (14 _M) is the signal received at the M antennas _(M a) is input.

In each searcher (14 ₁ , ---, 14 _M ) receiving a signal from the antenna elements (A ₁ , A ₂ , ---, A _M ), a signal with a spreading code such as the spreading code of the desired user Search for large reception in the direction.

FIG. 5 illustrates an example of a search result of the parallel searcher 14. Referring to the search result of FIG. 5, the search for the second signal searches that the signal delayed by one chip in the direction of the second antenna element is greatly received. In the three-signal searcher, it was found that the signal without the chip delay was largely received in the third antenna direction, and in the fourth signal searcher, the signal without the chip delay was greatly received in the fourth antenna direction. Further, the fifth signal searcher detects that a signal without a chip delay and a signal delayed by two chips are largely received in the fifth antenna direction, and the six delay signal searcher receives a large signal with a chip delayed by the sixth antenna. It was. That is, the signal without the chip delay is largely received in the third antenna, the fourth antenna, and the fifth antenna direction, the signal delayed by one chip is largely received from the second antenna direction and the sixth antenna direction, and the two chips are delayed signals. It can be seen that is largely received in the fifth antenna direction. At this time, the search result of the parallel searcher 14 is sent to the controller 15, and the controller 15 uses this information to control the switching and combiner 11 as follows.

That is, the signals received from the third antenna, the fourth antenna, and the fifth antenna are combined and sent to the first finger 12 ₁ , and the signals received from the second antenna and the sixth antenna are combined to the second finger 12 _2. ), And the signal received from the fifth antenna is sent to the third finger (not shown). In this case, the signal input to the first finger 12 ₁ is a signal without a chip delay, the signal input to the second finger 12 ₂ is a signal delayed by one chip, and the signal input to the third finger is two chips. This is a delayed signal. Accordingly, the first finger 12 ₁ receives a signal without chip delay, despreads the signal, and outputs the second finger 12 _2. The second finger 12 ₂ despreads a signal delayed by one chip. The third finger outputs the second chip by despreading the delayed signal. The signals output from each finger 12 ₁ , 12 ₂ , ---, 12 _K are summed and outputted by the ratio of each path signal power received after the time delay is considered in the maximum non-coupler 13. The signal output from the RAKE receiver 4 ₁ , 4 ₂ , ---, 4 _N is processed in the same manner as the current CDMA base station system. That is, the output signal of the RAKE receiver 4 ₁ , 4 ₂ , ---, 4 _N is determined by the determiner 5 ₁ , 5 ₂ , ---, 5 _N whether the digital value is 1 or 0. After deinterleaving at the deinterleaver 6 ₁ , 6 ₂ , ---, 6 _N , the error is corrected at the Viterbi decoder 7 ₁ , 7 ₂ , ---, 7 _N.

The system can also be designed as a system having a non-directional array antenna element, the base station system block diagram according to this is shown in FIG. In FIG. 6, the same components as those in FIG. 3 are denoted by the same reference numerals, and detailed description thereof will be omitted.

In the base station system of FIG. 6, the base station receives a signal by using the omni-directional array antenna elements B ₁ , B ₂ , ---, B _M , and then transmits the signal to the M having directivity in the beamforming unit 22. Is made of signals. FIG. 7 illustrates the beamforming unit 22 shown in FIG. 6 in detail. In the beamforming unit 22, as shown in FIG. 7, each antenna element B ₁ , B ₂ , ---, B _M is illustrated. By multiplying the digital data received by the complex weight vector corresponding to the different directions, M output signals are equivalent to receiving signals in different M directions. That is, the M output signals are equal to the digital signals received at the M directional antennas. The relationship between the input signal and the output signal in the beamforming unit 22 of FIG. 7 is as follows.

-------------- (One)

In equation (1) Of the beamforming unit 22 k Output signal, s _m (n) silver m Digital signal received from the first antenna, w _m ^k Is k To receive signals only from the first direction m The complex weight multiplied by the digital data received from the first antenna. If the distance between the antenna sensors is half of the wavelength corresponding to the maximum frequency, w _m ^k Is Becomes θ _k Is when the cells (or sectors) are divided equally in M directions. k th Direction. Therefore, the output signal of the beamforming unit 22 is the same as the output signal of the A / D converters 3 ₁ , 3 ₂ , ---, 3 _M when the directional antenna is used in FIG. In the same manner as in the case of using the directional antenna in the RAKE receiver of FIG.

When transmitting a signal to a user (forward channel), as in the case of reception, a plurality of directional antennas are used. When the search result of the parallel searcher 14 is transmitted to the controller 15 in the RAKE receiver of FIG. 4, the controller 15 uses this information to determine an antenna to transmit a corresponding signal. Transmission is in all directions in which the signal is received, with the time delay of each path signal being compensated for. That is, when a signal is received as shown in FIG. 5, the controller 15 transmits the signal to be transmitted in the direction of the fifth antenna, and also transmits the same signal in the direction of the second antenna and the sixth antenna by one chip delay, and the two chips. Transmission is delayed in the direction of the third antenna, the fourth antenna, and the fifth antenna. Therefore, when the user receives these signals, the time delays of the respective direction signals are similar to each other, so that they can be received almost simultaneously.

As described above, according to the present invention, it is possible to transmit and receive a signal in a direction of a desired user without performing calculation by spatial filtering using a directional antenna, thereby reducing the size of a cell in a future system such as IMT-2000. It is possible to provide a high quality multimedia service to many users without having to.

In addition, even when the angular dispersion of the received signal is large (that is, when the user's signal is widely spread and received), all the signals of the antenna direction having the received power over the threshold are received and despreading is performed, thereby improving the performance of the system. And more stable signal reception.

Therefore, it is possible to implement a base station system capable of providing a high quality multimedia service without significantly increasing the cost and complexity of the system.

Claims (3)

A plurality of directional array antenna elements A ₁ , A ₂ , ---, A _M ; A plurality of low noise amplifiers 1 ₁ , 1 ₂ , ----, 1 _M for amplifying a signal received from the antenna elements A ₁ , A ₂ , ---, A _M ; A low noise amplifier _{(1 1, 1 2, ----} , 1 M) to a plurality of down converter for converting the amplified signal into an I channel and a baseband signal of a Q channel signal by means _{(21, 22,} - -, 2 _M ); A plurality of A / D converters (3 ₁ ) for converting the signal converted by this down converter (2 ₁ , 2 ₂ , ---, 2 _M ) into a digital signal having a data rate higher than that of the system spreading code. , 3 ₂ , ---, 3 _M ); A switching and combiner 11 for switching together and outputting the corresponding signal in accordance with the degree of chip delay of the signal input from the A / D converter 3 ₁ , 3 ₂ , ---, 3 _M ; Search for which antenna element direction is largely received by the digital signal received from the A / D converter (3 ₁ , 3 ₂ , ---, 3 _M ) with a spread code such as a spread code of a desired user A parallel searcher 14 consisting of a plurality of signal searchers 14 ₁ , ----, 14 _M , A controller 15 which receives the search result of the parallel searcher 14 and controls the switching and combiner 11 based on the information; A plurality of fingers 12 ₁ , 12 ₂ , ---, 12 _K that receive the output signal from the switching and combiner 11 and perform despreading; A plurality of non-couplers 13 having a maximum non-coupler 13 which takes into account the time delay for the output signal from this finger 12 ₁ , 12 ₂ , ---, 12 _K and then sums and outputs the ratio of the power of each received path signal. RAKE receiver (4 ₁ , 4 ₂ , ---, 4 _N ); A plurality of judges 5 ₁ , 5 ₂ ,-which receive signals output from the RAKE receivers 4 ₁ , 4 ₂ , ---, 4 _N and judge whether the digital value is 1 or 0. -, 5 _N ); A deinterleaver 6 ₁ , 6 ₂ , ---, 6 _{N for} receiving and outputting an output signal from the judging device 5 ₁ , 5 ₂ , ---, 5 _N ; A Viterbi decoder (7 ₁ , 7 ₂ , ---, 7 _N ) that receives an output signal from the deinterleaver (6 ₁ , 6 ₂ , ---, 6 _N ) and corrects an error, ; Estimating the path signal reception power of the user received from each antenna element direction using the plurality of searchers, and performing a despreading operation by combining the signal of the antenna direction having a reception power of more than a threshold value among them; Smart antenna system using. The method of claim 1, wherein when the search result of the parallel searcher 14 is transmitted to the controller 15, the controller 15 determines an antenna to transmit the corresponding signal based on this information, and receives the received user signal. After estimating the path direction and time delay of the smart antenna system using a parallel probe, it is possible to transmit the signal by compensating the time delay in the direction of all path signals received above the threshold value. A plurality of non-directional array antenna elements B ₁ , B ₂ , ---, B _M ; A plurality of low noise amplifiers 1 ₁ , 1 ₂ , ----, 1 _M for amplifying a signal received from the antenna elements B ₁ , B ₂ , ---, B _M ; A low noise amplifier _{(1 1, 1 2, ----} , 1 M) to a plurality of down converter for converting the amplified signal into an I channel and a baseband signal of a Q channel signal by means _{(21, 22,} - -, 2 _M ); A plurality of A / D converters (3 ₁ ) for converting the signal converted by this down converter (2 ₁ , 2 ₂ , ---, 2 _M ) into a digital signal having a data rate higher than that of the system spreading code. , 3 ₂ , ---, 3 _M ); After receiving the digital signal input from this A / D converter (3 ₁ , 3 ₂ , ---, 3 _M ), M output signals are multiplied by multiplying corresponding digital data by complex weight vectors corresponding to different directions. A beamforming unit 22 which is made of M signals having directivity that is equivalent to receiving signals in M different directions; A switching and combiner 11 for switching and coupling and outputting the corresponding signal according to the degree of chip delay of the signal input from the A / D converter 3 ₁ , 3 ₂ , ---, 3 _M ; Search for which antenna element direction is largely received by the digital signal received from the A / D converter (3 ₁ , 3 ₂ , ---, 3 _M ) with a spread code such as a spread code of a desired user A parallel searcher 14 consisting of a plurality of signal searchers 14 ₁ , ----, 14 _M , A controller 15 which receives the search result of the parallel searcher 14 and controls the switching and combiner 11 based on the information; A plurality of fingers 12 ₁ , 12 ₂ , ---, 12 _K that receive the output signal from the switching and combiner 11 and perform despreading; A plurality of non-couplers 13 having a maximum non-coupler 13 which takes into account the time delay for the output signal from this finger 12 ₁ , 12 ₂ , ---, 12 _K and then sums and outputs the ratio of the power of each received path signal. RAKE receiver (4 ₁ , 4 ₂ , ---, 4 _N ); A plurality of judges 5 ₁ , 5 ₂ ,-which receive signals output from the RAKE receivers 4 ₁ , 4 ₂ , ---, 4 _N and judge whether the digital value is 1 or 0. -, 5 _N ); A deinterleaver 6 ₁ , 6 ₂ , ---, 6 _{N for} receiving and outputting an output signal from the judging device 5 ₁ , 5 ₂ , ---, 5 _N ; A Viterbi decoder (7 ₁ , 7 ₂ , ---, 7 _N ) that receives an output signal from the deinterleaver (6 ₁ , 6 ₂ , ---, 6 _N ) and corrects an error, ; After dividing a cell (or sector) into a plurality of directions, a complex weight vector for each direction is multiplied by a signal received from each antenna element to produce a plurality of signals having a directivity, and then each antenna element using the plurality of searchers. A smart antenna system using a parallel probe, characterized in that to estimate the path signal received power of the user received from the direction, and to perform despreading by combining the signal of the antenna direction having a received power of more than a threshold value among them.