KR20050062330A - A transmitting and receiving apparatus for base station with smart antenna, and a beam forming method in downlink - Google Patents

Abstract

The present invention relates to a smart antenna base transceiver station for transmitting a signal from a base station to a mobile station in a wireless communication system using an array antenna or a smart antenna, and a fixed beam forming method of a forward link. An apparatus for forming and transmitting a smart antenna according to the present invention includes: multipath searching means for detecting and outputting multipath delay information for each demodulation channel for a signal received through a plurality of antennas; Demodulation means for demodulating the multipath delay information by forming an adaptive beam for each demodulation channel, and outputting an adaptive beam weight vector generated during demodulation; Control means for selecting at least one forward beam index for each demodulation channel by using a correlation between the adaptive beam weight vector and a plurality of predetermined fixed beam weight vectors; And modulation means for selecting a forward fixed beam corresponding to each of the at least one forward beam index and forming a switching beam for a modulation signal for each modulation channel, and outputting the switching beam to the forward link. According to the present invention, in the wireless communication system using the array antenna, it is possible to easily form a fixed beam of the forward link without increasing the complexity of the terminal or the complexity of the base station receiver.

Description

Smart Antenna Base Station Transceiver and Fixed Beam Formation Method of Forward Link {A TRANSMITTING AND RECEIVING APPARATUS FOR BASE STATION WITH SMART ANTENNA, AND A BEAM FORMING METHOD IN DOWNLINK}

The present invention relates to a smart antenna base station transceiver and a fixed beam forming method of the forward link, and more particularly, in a wireless communication system using an antenna array or a smart antenna, from a base station to a mobile station The present invention relates to a smart antenna base station transceiver and signal for transmitting a signal and a fixed beam forming method of a downlink.

To fully implement a mobile communication system that allows any type of data to send and receive with the desired party anytime, anywhere, operates under a single, globally standardized standard, and is a much higher level of service than current mobile communication systems. Next generation (3rd Generation) mobile communication systems that provide a commercially available.

The next generation mobile communication system transmits and receives images and other data with high reliability as well as voice signals currently in service. In addition, as services are diversified, the bandwidth of transmission and reception data occupies a much wider band than the present, and the demand of the mobile communication network itself is expected to increase further.

Therefore, the most important technical challenge of the next generation mobile communication system should be to present a technique for transmitting more data reliably using the narrowest bandwidth possible.

However, the reduction of bandwidth used and the increase of reliability cannot be achieved at the same time, so the existing technologies proposed to date cannot solve the capacity and reliability problems that will arise in the next generation of mobile communication.

In recent years, new technologies are being actively researched to adjust the beam pattern of the antenna to suppress interference and noise, thereby simultaneously increasing capacity and improving reliability in a communication system. The so-called smart antenna technology is emerging as the core technology of the next generation mobile communication system.

Such a smart antenna technology can be said that the base station sets the optimal beam to the subscribers of the wireless communication terminal, thereby reducing the radio interference to increase the communication capacity and improve the communication quality.

For example, a smart antenna system installed in a base station may adapt to the speed of each of 1) fixed targets such as offices, 2) slow moving targets such as personal and satellite, and 3) fast moving targets such as vehicles and trains. In this way, the optimum beam pattern is continuously provided to provide maximum gain in the direction of the target, and relatively much smaller gain in the other direction, thereby suppressing interference. That is, such a smart antenna system increases the capacity of the mobile communication system and improves the reliability of communication.

Therefore, such smart antenna technology is the latest technology to be applied to W-CDMA and CDMA2000, which is a next-generation communication method that must reliably transmit a lot of data.

On the other hand, when the smart antenna technology is introduced to the base station in the mobile communication environment, there are two methods that can be applied to the forward and reverse direction is the adaptive beam forming method and the fixed beam forming method.

The adaptive beamforming method is a method of beamforming by continuously changing a beam weight vector adaptively according to a changing environment of a channel.

On the other hand, in the fixed beam forming method, each fixed beam weight vector is predetermined for a fixed number of fixed beams, and as shown in FIG. 1, the fixed beam index 120 depends on the direction of the array antenna 110 of the mobile station. This is a method of performing beam forming by changing). 1 is a diagram illustrating a fixed beam pattern of a forward link according to the prior art.

In general, in the case of the base station receiving end of the reverse link, adaptive beamforming methods are frequently used. On the other hand, in the case of the base station transmitting end of the forward link, it depends on the time division multiplexing (TDD) method and the frequency division multiplexing (FDD) method. The adaptive beamforming method which uses the adaptive beam weight vector of N for the forward link is used a lot.

However, in the frequency division multiplexing (FDD) scheme, since the frequencies in the reverse and forward directions are different, the adaptive beam weight vector of the reverse link cannot be used for the forward link as it is. Therefore, the mobile station measures a channel of the forward link and feeds back channel information to the base station, thereby using a method of performing adaptive beam or fixed beam formation on the forward link.

That is, in the conventional method, the feedback information is received from the terminal to perform beamforming of the forward link, or the receiving end estimates the incidence angle (DOA) of the received signal separately from the demodulator and uses the beamforming of the forward link.

As described above, the method in which the mobile station measures the channel information of the forward link, feeds it back to the base station, and applies it to beamforming of the forward link may be effective when the channel characteristics are good or the speed of the mobile station is low. However, when the channel characteristics are poor or the speed of the mobile station is high, there is a problem that performance may be very degraded due to an error or feedback delay occurring in the channel during feedback of the channel information.

In addition, since the mobile station must continuously report the channel characteristics of the forward link to the base station in the measurement, the mobile station becomes very complicated and also needs to send feedback information on the reverse link, thereby reducing the capacity of the reverse link. have.

On the other hand, as shown in Figure 2, there is another method for performing fixed beam formation in the forward link. FIG. 2 is a diagram illustrating a transceiver structure for determining a fixed beam index of a forward link by using a search result of a switching beamforming searcher of a reverse link according to the related art. Here, the specific operation of each block will be described later with reference to FIG. 3 in the detailed description of the present invention.

The base station transceiver shown in FIG. 2 has a switching beamforming multi-channel searcher 260 to select a beam index having the largest energy of the received signal and use the fixed beam index of the forward link. In the base station transceiver, since the switching beamforming multi-channel searcher 260 must search for all of the fixed beam patterns, the complexity of the switching beamforming multichannel searcher 260 has a problem of increasing by the number of fixed beams. . For example, in a WCDMA mobile communication system, assuming that a search interval is 64 chips and a resolution of 1/2 chip, 128 correlators are required for a typical searcher. For the switching beamforming multi-channel searcher 260 forming 12 beams according to this, 128 x 12 correlators are required.

 Meanwhile, as a prior art, US Patent No. US 5,634,199 (filed April 17, 1995) discloses an invention named "Method of Subspace Beamforming using Adaptive Transmitting Antennas with Feedback", which is a CDMA mobile communication. The present invention relates to a method for obtaining channel information of a forward link in a system and a method for obtaining a forward beamforming weight using the same.

Specifically, according to the invention of US Pat. No. 5,634,199, in order to reduce the amount of feedback data sent by the mobile station to the base station, the base station transmits several probe signals, and the terminal obtains a correlation matrix for the probe signals to the base station. Feedback. At this time, the base station calculates the forward beamforming weight using the correlation matrix fed back to each terminal. However, since the present invention uses the adaptive beamforming method using the feedback information of the mobile station in the forward link, the performance is excellent when the channel environment is good, but the performance is poor when the channel environment is bad.

Meanwhile, as a related art, Korean Patent Application No. 2000-67975 (filed Nov. 16, 2000) discloses a "forward beam forming system and method using a reverse array response vector". Provided is a forward beamforming system and method for forming an antenna beam having a maximum gain in a direction in which is located.

Specifically, according to the invention of Korean Patent Application No. 2000-67975, two methods for performing forward beamforming using a received array response vector estimated in the reverse direction are proposed. First, by estimating the angle of signal arrival An algorithm for forming a maximum antenna gain in a desired user direction, the method of increasing the angle of arrival estimation, and secondly, a transmission beamforming weight vector by multiplying a response transform matrix by a reception antenna response vector estimated using the reception array response vector. By presenting a method of directly obtaining the antenna beam forming having the maximum gain in the direction in which the desired user is located is possible. However, there is a problem that the present invention mainly considers only the maximum gain performance and does not consider the complexity of the base station.

On the other hand, as a prior art, a volume of paper entitled "Semi-Blind Method for Transmit Antenna Array in CDMA System" is published in Volume 1, pages 189-194 of VTC2000, published in the fall of 2000. In a CDMA mobile communication system using the method, a method of obtaining a forward channel information by a base station using terminal feedback and a method of obtaining a forward beamforming weight using the same are disclosed.

Specifically, the preceding paper estimates an array response vector by acquiring only backward data, and proposes a method of using only fast fading components to be fed back from the terminal to calculate the forward beamforming weight. The problem of the open loop beam forming method can be solved. However, the preceding paper can solve the problem of the open loop beam forming method to some extent by using the adaptive beam forming method in the forward direction, but there is a problem that the complexity of the terminal or the complexity of the base station receiver can be increased.

An object of the present invention for solving the above problems is a smart antenna base station transceiver and a forward link fixed beam forming method that can easily form a beam of the forward link using the inner product of the reverse adaptive beam weight vector and the fixed beam weight vector. It is to provide.

In addition, another object of the present invention is to provide a smart antenna base station transceiver and a fixed beam forming method of the forward link that can improve the performance of the forward link without increasing the complexity of the terminal or the complexity of the base station receiver.

As a means for achieving the above object, the smart antenna base station transceiver according to the present invention,

Multipath searching means for detecting and outputting multipath delay information for each demodulation channel for signals received through the plurality of antennas;

Demodulation means for performing demodulation by forming adaptive beams for each demodulation channel for the received signal using the multipath delay information for each demodulation channel, and outputting one or more adaptive beam weight vectors generated during the demodulation for each demodulation channel. ;

Control means for selecting at least one forward beam index for each demodulation channel by using a correlation between the adaptive beam weight vector and a plurality of preset fixed beam weight vectors; And

Modulation means for selecting a forward fixed beam corresponding to each of the at least one forward beam index and forming a switching beam for a modulation signal for each modulation channel and outputting the forwarding beam to a forward link;

There is a feature configured to include.

Here, the demodulation means includes a plurality of demodulators, each demodulator comprising: a plurality of adaptive beam forming finger blocks; And a combiner configured to combine the outputs of the plurality of adaptive beamforming finger blocks and output the combined signal to the channel decoder.

The adaptive beamforming finger block may include: an adaptive beam weight vector vector operator configured to extract an adaptive beam weight vector from a received signal in real time using multipath delay information; A multiplier for multiplying the adaptive beam weight vector operator output to a received signal in real time; And receiving the multiplier output as input, performing respreading of the DS-CDMA signal using the multipath delay information, and performing time tracking, channel estimation, and coherent demodulation, and demodulating the demodulated symbol values. It may include a finger that continuously outputs the time average value of the demodulation symbol energy to the controller.

In this case, the adaptive beamforming finger block may be configured to send the adaptive beam weight vector and the symbol energy value output from the finger in real time to the control means in real time.

The control means may include: a weight vector table in which a fixed beam weight vector adapted to a reverse frequency is preset; An adaptive beam weight vector selector for each channel for selecting one or more of the adaptive beam weight vectors outputted from the demodulation means for each channel starting from a larger finger energy; A product dot product and a squarer for each channel, which output an inner product of the selected adaptive beam weight vector and the fixed beam vector of the weight vector table, respectively and output a square value thereof; And a beam index selector for selecting a beam index from the output of the vector dot product and the squarer to output a forward beam index.

The beam index selector may include one or more adaptive beamforming weight vectors selected by the adaptive beam weight vector selector for each channel. Beamforming weight vector equal to the number of fixed beams of the pre-stored forward link with To the equation A squared vector dot product, wherein H is a Hermitian operator, selects a forward beam index.

Here, when the frequency of the forward link and the reverse link is different frequency division multiplexing (FDD) method, the same pattern as the fixed beam pattern of the forward link is formed, but is adjusted to the frequency of the reverse link by the fixed beamforming weight vector A reverse fixed beam weight vector is used.

Here, when the number of adaptive beam weight vectors selected by the adaptive beam weight vector selector for each channel is 1, at least one or more beam indexes based on having the largest value among squared values of the vector dot product of the fixed beam number of the forward link Is selected and used as the fixed beam index of the forward link.

Here, the fixed beam weight vector is used in common for all channels (the same as the number of modulators) in which the fixed beam of the forward link is formed, as much as the fixed beam number of the forward link.

Here, the forward beam index is selected based on the total received energy of each fixed beam.

Here, the modulation means, a plurality of modulators for respectively modulating the encoded data of the base station for transmission on the forward link using the at least one or more forward beam index to select one or more forward fixed beam for each channel to the plurality of A plurality of forward beam selectors for outputting a signal output from a modulator to a selected forward fixed beam A plurality of forward fixed beam formers and a plurality of forward fixed beam formers respectively forming a fixed beam by using a beam weight vector may include a plurality of antenna adders for outputting by adding all the outputs for each antenna.

Here, each of the plurality of forward beam selectors outputs only one or more fixed beams selected from all the fixed beams, and does not output the remaining non-selected beams.

On the other hand, as another means for achieving the above object, the smart antenna transmitting and receiving beam forming apparatus according to the present invention,

A plurality of array antennas for providing a beam pattern to a terminal user in a forward link or a reverse link;

An RF / IF converter for converting a signal transmitted and received through the array antenna from a radio frequency band to an intermediate frequency band or a base band;

A multipath searcher for detecting and outputting multipath delay information for each demodulation channel with respect to signals received through the plurality of array antennas;

An adaptive beamforming demodulator configured to demodulate an adaptive beam corresponding to the multipath delay information and the received signal, and output an adaptive beam weight vector generated in the demodulation for each channel;

A forward beam controller for selecting at least one forward beam index for each channel by using the correlation between the adaptive beam weight vector and a plurality of preset fixed beam weight vectors; And

A switching beamforming modulator for selecting a forward fixed beam corresponding to each of the at least one forward beam index and forming a switching beam for a modulated signal for each channel, and outputting the switching beam to a forward link

There is a feature configured to include.

On the other hand, as another means for achieving the above object, a forward link fixed beam forming method of a base station having a plurality of antennas according to the present invention,

a) searching for multipath delay information for each demodulation channel for signals received through the plurality of antennas;

b) performing demodulation by forming an adaptive beam corresponding to a received signal using the multipath delay information for each demodulation channel;

c) outputting an adaptive beam weight vector generated for each demodulation for each channel;

d) selecting at least one forward beam index for each channel by using the correlation between the adaptive beam weight vector and a plurality of preset fixed beam weight vectors; And

e) selecting a forward fixed beam corresponding to each of the at least one forward beam index, and forming a switching beam for a modulation signal for each channel and outputting the forwarding beam to a forward link;

There is a feature consisting of.

Therefore, in the forward link fixed beam forming method according to the present invention, the fixed beam forming method is used, but an adaptive beam weight vector generated in the process of demodulating the signal received by the mobile station by the adaptive beam forming method and a plurality of predetermined fixed beam weights A method of taking a correlation value of a vector and transmitting a forward link signal to one or more fixed beams having the largest magnitude of the correlation value, wherein the maximum link performance is maximized without increasing the complexity of the terminal or the complexity of the base station receiver. Can be formed.

Hereinafter, a smart antenna base station transceiver and a fixed beam forming method of a forward link according to an embodiment of the present invention with reference to the accompanying drawings will be described in detail.

3 is a diagram illustrating a multi-channel base station transceiver structure used for forming a fixed beam of a forward link by using an adaptive beam weight vector generated in a process of demodulating a reverse link into adaptive beam shaping according to an embodiment of the present invention. As shown in Figure 3, this is enabled by placing the multi-channel forward beam controller block 500 between the modulator block 600 and the demodulator block 400.

As shown in FIG. 3, a base station transceiver having a forward link fixed beam forming apparatus of a base station having a plurality of antennas according to an embodiment of the present invention includes a multichannel encoder block 310 and a switching beam multichannel modulator block. (600), radio frequency / intermediate frequency (RF / IF) conversion block 330, N array antennas 340, multichannel multipath searcher block 360, adaptive beamforming multichannel demodulator block 400, Channel forward beam controller block 500 and a multi-channel decoder block 370, where a forward link fixed beam forming apparatus of a base station having a plurality of antennas according to an embodiment of the present invention is a multi-channel multipath searcher block 360, the adaptive beamforming multichannel demodulator block 400, the multichannel forward beam controller block 500, and the switching beam multichannel modulator block 600.

Referring to FIG. 3, the multi-channel multipath searcher block 360 selects one or more signals among N signals received through the N array antennas 340 to detect and output multipath delay information for each demodulation channel. do. Here, the channel is not a wireless channel, but refers to one modulator / demodulator pair, and there are M channels in the accompanying drawings.

The adaptive beamforming multi-channel demodulator block 400 demodulates an adaptive beam for each demodulated channel with respect to the received signal by using the multipath delay information for each demodulated channel, and demodulates the adaptive beam weight generated during the demodulation. More than one vector is output for each demodulation channel.

In addition, the multi-channel forward beam controller block 500 selects at least one forward beam index for each channel by using a correlation between the adaptive beam weight vector and a plurality of preset fixed beam weight vectors, thereby switching beams. To the multi-channel modulator block 600.

The switching beam multi-channel modulator block 600 selects a forward fixed beam corresponding to each of the at least one forward beam index, forms a switching beam for the modulation signal for each channel, and outputs it to the forward link.

4 is a diagram illustrating an adaptive beamforming multi-channel demodulator block of DS-CDMA using an adaptive beamforming method according to an embodiment of the present invention, and demodulating a received signal by forming an adaptive beam for each demodulation channel. In this case, the adaptive beam weight vector generated at this time is output for each demodulation channel.

As shown in FIG. 4, the adaptive beamforming multi-channel demodulator block 400 according to an embodiment of the present invention includes a plurality of demodulators 400-1,..., 400 -M, and each demodulator includes: A plurality of adaptive beamforming finger blocks 420-1, 420-2, ..., 420-F and a combiner 410 for combining the outputs of the plurality of adaptive beamforming finger blocks and outputting them to a channel decoder; .

Here, each of the plurality of adaptive beamforming finger blocks 420-1, 420-2, ..., 420-F uses an adaptive beam weighting vector for extracting an adaptive beam weight vector from a received signal in real time using the multipath delay information. Vector operators 421-1, 421-2, ..., 421-F; Multipliers (422-1, 422-2, ..., 422-F) that multiply the received beam weight vector operator output to a received signal in real time; And receiving the multiplier output as input, performing respreading of the DS-CDMA signal using the multipath delay information, and performing time tracking, channel estimation, and coherent demodulation, and demodulating the demodulated symbol values. And fingers 423-1, 423-2, ..., 423-F which continuously output the time average value of the demodulated symbol energy to the controller.

Here, the adaptive beamforming finger block sends the adaptive beam weight vector output in real time from the adaptive beam weight vector calculator and the symbol energy value output in real time from the finger to the control means in real time.

FIG. 5 is a diagram illustrating a multi-channel forward beam controller block according to an embodiment of the present invention, wherein the multi-channel forward beam controller block 500 independently and simultaneously independently records a total of M channels 520-1,..., 520 -M. It may be controlled, and includes a reverse fixed beamforming weight vector table 510, an adaptive beam weight vector selector 521 for each channel, a vector dot product and squarer 522 for each channel, and a beam index selector 523 for each channel.

The weight vector table 510 is preset with a weight vector corresponding to fixed beam formation according to the reverse frequency, and the adaptive beam weight vector selector 521 for each channel includes a plurality of corresponding channels output from the demodulator block 400. One or more adaptive beam weight vectors are selected starting from the larger one among the three adaptive beam weight vectors.

In addition, the channel-specific vector dot product and the squarer 522 internalize the selected adaptive beam weight vector and the fixed beam vector of the weight vector table, respectively, and output the squared value, and the beam index selector 523 is configured to perform the One or more beam indices are selected from the output of the vector dot product and the squarer to output the forward beam indices.

6 is a diagram illustrating a switching beam forming multichannel (M channel) modulator block according to an embodiment of the present invention, wherein the switching beam multichannel modulator block 600 is for each channel of a base station for transmitting on a forward link. A plurality of modulators 610-1, ..., 610-M each functioning to modulate and spread the encoded data according to the WCDMA standard; A channel-specific forward beam selector 620-1, ..., 620-M that selects one or more forward fixed beams by using the one or more forward beam indexes for each channel and outputs a signal output from the modulator to the selected forward fixed beam. ); A plurality of (L) beam adders (630-1, ..., 630-L) for adding the outputs of each of the plurality of forward beam selectors to each beam; A plurality of forward fixed beam formers 640-1,..., 640 -L for forming the fixed beams by using the predetermined forward fixed beam weight vector for each beam; And a plurality of antenna adders 650-1,..., 650 -N for adding and outputting the outputs of the plurality of forward fixed beam formers for each antenna.

Hereinafter, a method of forming a fixed beam of a forward link according to an embodiment of the present invention will be described with reference to FIGS. 3 to 6.

First, as shown in FIG. 3, the forward beam controller block 500 includes one or more reverse link adaptive beam weight vectors for each channel currently in talks from the adaptive beamforming demodulator block 400. It is provided periodically. Here, P is greater than or equal to 1, and if the embodiment of the present invention is applied to the DS-CDMA scheme, it may be equal to the number of fingers. In addition, when an embodiment of the present invention is applied to the DS-CDMA scheme, an energy estimate of each finger is also provided.

Typically, a base station of a DS-CDMA mobile communication system has a plurality of demodulators for receiving signals from a plurality of terminals provided by the base station, each demodulator for obtaining diversity gain according to a multipath of a channel. It includes a plurality of fingers.

At this time, by combining the results of the plurality of fingers, the receiver achieves a diversity gain to mitigate fading effects according to mobility and wireless network environment. For example, because the base station antenna receives multiple signals with different propagation delays over each of the same RF signals transmitted from the terminal, the controller of the receiver assigns each finger to process and demodulate different multipaths. By combining the results from multiple fingers, path diversity is achieved to improve receiver performance.

In addition, the receiver in the base station of the CDMA mobile communication system includes an energy estimator for each finger, and estimates the finger energy accordingly. A typical finger energy estimator calculates the signal energy captured by a corresponding finger, averages a number of signal energy values, and maps the estimates from each average signal energy value using a table that maps the energy values to the estimates. You will get it.

The adaptive beam weight vector Is a normalized weight vector that is used to form an adaptive beam in real time for each finger when the demodulator demodulates the received signal.

First, as shown in FIG. 4, the demodulator block 400 outputs an adaptive beam weight vector and finger energy of each finger currently being used for demodulation for each channel to the forward beam controller block 500.

Next, referring to FIG. 5, the forward beam controller block 500 is provided with at least one adaptive beam weight vector and finger energy for each channel that is currently being talked to from the demodulator block 400 to adapt the illustrated in FIG. 5. One or more adaptive beam weight vectors, starting with the largest finger energy in beam weight vector selector 521. Select. here, to be.

The selected K adaptive beam weight vectors Normalized Reverse Fixed Beam Weight Vectors in Table 1 and Reverse Fixed Beam Formation Weight Vector Table 510. After obtaining the squared value of the vector dot product in the vector dot product 522, the beam index selector 523 selects one or more forward fixed beam indices by using the square value of L × K vector dot products in the corresponding channel. 520-1,..., 520 -M to the modulator block 600.

Meanwhile, Equation 1 as follows First reverse fixed beam weight vector H represents the square of the vector dot product of the first backward adaptive beam weight vector, and H represents the Hermitian operator.

In addition, when the number K of the adaptive beam weight vectors is 1, at least one beam index is selected based on the largest value among squared values of the vector dot product of the fixed beam number of the forward link, and thus the forward direction is selected. Can be used as a fixed beam index of the link.

In addition, the fixed beam weight vector is used in common for all modulation channels in which the fixed beam of the forward link is formed by the number of the fixed beams of the forward link.

Here, the reason for defining the L reverse fixed beam weight vector is the forward link where the fixed beam pattern is actually used, but if the frequency of the forward link and the reverse link is different, for example, in the FDD scheme, This is because the beam weight vector may be different according to the frequency even if the number of the fixed beams and the beam pattern are the same.

That is, when the embodiment of the present invention in which the switching beam is formed in the forward link using the fixed beam pattern as shown in FIG. It is more efficient to use a reverse link fixed beam weight vector tailored to the reverse frequency that produces the same pattern as the beam pattern of the forward link, rather than direct vector dot product with the vector.

In Equation 1, L × K vector dot product squared values There are a number of ways to select the forward fixed beam index by using the following, only one example will be described below.

First, representing the total received energy for each fixed beam, as shown in Equation 2 below. Define.

Where Is the demodulation energy of the kth finger, Denotes the square of the vector dot product of the first reverse fixed beam weight vector and the second reverse adaptive beam weight vector defined in Equation 1, and Equation 2 denotes the total energy of K fingers in the i th fixed beam beam direction. it means.

The beam index selector according to the embodiment of the present invention After calculating, we select one or more beam indices starting with the largest value among L and send it to the modulator corresponding to the channel.

Referring to FIG. 6, the switching beamforming multichannel modulator block 600 receives one or more fixed beam indices for each channel selected by the forward beam controller block 500, and uses the index value to determine the multichannel modulator block. The forward beam selectors 620-1,..., 620 -M in 600 select one or more forward fixed beams per channel.

In addition, the forward beam selectors 620-1, ..., 620-M for each channel output an output for only one or more fixed beams selected from a total of L fixed beams, although L output ports each have the same number of forward beams. No output is made for the remaining unselected beams (ie output is zero for the remaining unselected beams).

The L output ports of the forward beam selectors 620-1,..., 620 -M for each channel are connected to the input ports of the adders 630-1,. Each beam adder 630-1,..., 630 -L receives M inputs from M forward beam selectors one by one and adds them to each beam.

The L beam adders 630-1,..., 630-L outputs are respectively input to the inputs of the forward fixed beam formers 640-1,. .

When performing forward beamforming in the L forward fixed beam formers 640-1,..., 640 -L, the input signal is multiplied by a fixed beam weight vector for each beam having a length of N (that is, the number of antennas), and then outputs each. This is N.

The N outputs of each of the L forward fixed beam formers 640-1,..., 640 -L are added for each antenna in the antenna-based adders 650-1,. It is output to the IF converter 330.

Meanwhile, the multi-channel forward beam controller block 500 according to the embodiment of the present invention may be located in the switching beamforming multichannel modulator block 600 or in the adaptive beamforming multichannel demodulator block 400. have.

As a result, the beamforming method of the forward link according to the embodiment of the present invention uses a fixed beamforming method, and an adaptive beam weight vector generated in the process of demodulating the signal received by the mobile station using the adaptive beamforming method and a plurality of predetermined predetermined beams. A correlation value of the two fixed beam weight vectors is taken, and the forward link signal is transmitted to the one or more fixed beams having the largest magnitude.

Therefore, compared to the conventional technology of receiving the feedback information from the terminal and performing beamforming of the forward link, or estimating the incident angle of the received signal separately from the demodulator at the receiving end and using the beamforming of the forward link, the embodiment of the present invention provides the terminal. It is possible to form a beam of the forward link without increasing the complexity of the base station receiver or the complexity of the base station receiver.

While the invention has been shown and described in connection with specific embodiments thereof, it will be appreciated that various modifications and changes can be made without departing from the spirit and scope of the invention as indicated by the claims. Anyone who owns it can easily find out.

According to the present invention, in a wireless system using an array antenna or a smart antenna, it is possible to easily form a beam of the forward link by using the inner product of the reverse adaptive beam weight vector and the fixed beam weight vector.

In addition, according to the present invention, it is possible to improve the performance of the forward link without increasing the complexity of the terminal or the complexity of the base station receiver.

1 is a diagram illustrating a fixed beam pattern of a forward link according to the prior art.

FIG. 2 is a diagram illustrating a base station transceiver structure for explaining determining a fixed beam index of a forward link by using a search result of a switching beamforming searcher of a reverse link according to the related art.

3 illustrates a structure of a multi-channel base station transceiver for explaining the use of fixed beam shaping of a forward link by using an adaptive beam weight vector generated in a process of demodulating a reverse link into adaptive beam shaping according to an embodiment of the present invention. It is a figure.

4 illustrates an adaptive beamforming multichannel demodulator block according to an embodiment of the present invention.

5 illustrates a multi-channel forward beam controller block according to an embodiment of the present invention.

6 illustrates a switching beamforming multichannel modulator block according to an embodiment of the present invention.

Claims (17)

In the transceiver of the smart antenna base station having a plurality of antennas, Multipath searching means for detecting and outputting multipath delay information for each demodulation channel for signals received through the plurality of antennas; Demodulation means for performing demodulation by forming adaptive beams for each demodulation channel for the received signal using the multipath delay information for each demodulation channel, and outputting one or more adaptive beam weight vectors generated during the demodulation for each demodulation channel. ; Control means for selecting at least one forward beam index for each channel by using a correlation between the adaptive beam weight vector and a plurality of preset fixed beam weight vectors; And Modulating means for selecting a forward fixed beam corresponding to at least one forward beam index for each channel to form a switching beam for a modulated signal for each channel and outputting the forwarding beam to a forward link; Smart antenna base station transceiver device comprising a. The method of claim 1, wherein the demodulation means comprises a plurality of demodulators, each demodulator comprising: A plurality of adaptive beamforming finger blocks; And A combiner for combining the outputs of the plurality of adaptive beamforming finger blocks and outputting them to a channel decoder Smart antenna base station transceiver device comprising a. The method of claim 2, wherein the plurality of adaptive beam forming finger blocks, An adaptive beam weight vector vector operator for extracting an adaptive beam weight vector from the received signal in real time using the multipath delay information; A multiplier for multiplying the adaptive beam weight vector operator output to a received signal in real time; And Receives the multiplier output as input and performs respreading of DS-CDMA signal using the multipath delay information, performs time tracking, channel estimation and coherent demodulation, and inputs the demodulated symbol value to the combiner. And a finger for continuously outputting a time average value of the demodulated symbol energy, and sending the adaptive beam weight vector output in real time from the adaptive beam weight vector operator and the symbol energy value output in real time from the finger to the control means in real time. Smart antenna base station transceiver device. The method of claim 1, wherein the control means, A weight vector table in which a fixed beam weight vector adapted to a reverse frequency is preset; An adaptive beam weight vector selector for each channel for selecting one or more of the adaptive beam weight vectors outputted from the demodulation means for each channel starting from a larger finger energy; A product dot product and a squarer for each channel, which output an inner product of the selected adaptive beam weight vector and the fixed beam vector of the weight vector table, respectively and output a square value thereof; And Beam index selector for each channel for outputting a forward beam index by selecting the beam index from the output of the vector dot product and the squarer Smart antenna base station transceiver device comprising a. The method of claim 4, wherein The beam index selector may include one or more adaptive beamforming weight vectors selected by the adaptive beam weight vector selector for each channel. Beamforming weight vector equal to the number of fixed beams of the pre-stored forward link with To the equation A smart antenna base station transceiver, characterized in that for selecting the forward beam index using a squared vector dot product, wherein H is a Hermitian operator. The method of claim 4, wherein In the case of the frequency division multiplexing (FDD) method in which the frequencies of the forward link and the reverse link are different, the same pattern as that of the fixed beam pattern of the forward link is formed, but is fixed to the frequency of the reverse link by the fixed beamforming weight vector. Smart antenna base station transceiver device using a beam weight vector. The method of claim 4, wherein When the number of adaptive beam weight vectors selected by the adaptive beam weight vector selector for each channel is 1, at least one or more beam indexes are selected based on the largest value among squares of the vector dot product of the fixed beam number of the forward link. And using as the fixed beam index of the forward link. The method of claim 4, wherein And the fixed beam weight vector table is commonly used for all channels in which the fixed beam of the forward link is formed. The method of claim 4 And a forward beam index for the one channel is selected based on the total received energy for each fixed beam for the channel. The method of claim 1, wherein the modulation means, A plurality of modulators each of which modulates and spreads channel-encoded data of a base station for transmission on a forward link according to WCDMA standards; A channel-specific forward beam selector for outputting a signal output from the modulator to a selected forward fixed beam by selecting one or more forward fixed beams using the one or more forward beam indexes for each channel; A plurality of beam adders for adding all of the outputs of each of the plurality of forward beam selectors beam by beam; A plurality of forward fixed beam formers respectively configured to form the fixed beams by using the forward fixed beam weight vectors predetermined for each beam by the adder output for each beam; And And a plurality of antenna adders for adding and outputting the outputs of each of the plurality of forward fixed beam formers for each antenna. Smart antenna base station transceiver device comprising a. The method of claim 10 Each of the plurality of forward beam selectors outputs only one or more fixed beams selected from all the fixed beams, and does not output the remaining unselected beams. A base station transceiver for forming a forward link fixed beam in a wireless communication system, A plurality of array antennas for providing a beam pattern to a terminal user in a forward link or a reverse link; An RF / IF converter for converting a signal transmitted and received through the array antenna from a radio frequency band to an intermediate frequency band or a base band; A multipath searcher for detecting and outputting multipath delay information on a signal received for each channel through the array antennas; An adaptive beamforming demodulator for performing demodulation by forming an adaptive beam for each demodulated channel with respect to the received signal using the multipath delay information, and outputting an adaptive beam weight vector generated by the demodulation for each channel; A forward beam controller for selecting at least one forward beam index for each channel by using the correlation between the adaptive beam weight vector and a plurality of preset fixed beam weight vectors; And A switching beamforming modulator for selecting a forward fixed beam corresponding to each of the at least one forward beam index and forming a switching beam for a modulated signal for each channel and outputting the switching beam to a forward link Smart antenna base station transceiver device comprising a. In the forward link fixed beam forming method of a base station having a plurality of antennas, a) searching for multipath delay information for each demodulation channel for signals received through the plurality of antennas; b) performing demodulation by forming an adaptive beam for each demodulation channel for the received signal using the multipath delay information; c) outputting an adaptive beam weight vector generated for each demodulation for each channel; d) selecting at least one forward beam index for each channel by using the correlation between the adaptive beam weight vector and a plurality of preset fixed beam weight vectors; And e) selecting a forward fixed beam corresponding to each of the at least one forward beam index, and forming a switching beam for a modulation signal for each channel and outputting the forwarding beam to a forward link; Fixed beam forming method of the forward link comprising a. The method of claim 13, Step d) includes one or more adaptive beamforming weight vectors of the reverse link. Beamforming weight vector equal to the number of fixed beams of the pre-stored forward link with To the equation A method for forming a fixed beam of a forward link, characterized in that it selects the forward beam index using a squared vector dot product, where H is a Hermitian operator. The method of claim 13, In step d), when the frequencies of the forward link and the reverse link are different, the same pattern as the fixed beam pattern of the forward link is formed, but the fixed beamforming weight vector is used to adjust the reverse fixed beam weight according to the frequency of the reverse link. A fixed beam forming method of a forward link, characterized in that it uses a vector. The method of claim 13, In step d), when the number of adaptive beam weight vectors is 1, at least one or more beam indexes are selected based on the largest value among squared values of a vector dot product of the fixed beam number of the forward link. A fixed beam forming method of a forward link, characterized in that it is used as a fixed beam index of the forward link. The method of claim 13, The forward beam index of step d) is selected based on the total received energy for each fixed beam fixed beam forming method of the forward link.