KR20120038906A - Continuous orthogonal spreading code based ultra-high performance array antenna system - Google Patents

Abstract

PURPOSE: A high performance arrangement antenna system based on a successive orthogonal diffusion code is provided to modulate user signals by filtering pre-rake synthesis signals. CONSTITUTION: A beam forming unit(410) multiplies a weighted value vector corresponding to each antenna(401-1~401-M) by a pre-rake synthesis signal received by the antennas. The beam forming unit creates the reception beam of a chip level for the pre-rake synthesis signals according to each user. A reverse diffusing unit(460) modulates plural user signals by filtering the processed pre-rake synthesis signal.

Description

Continuous orthogonal spreading code based ultra-high performance array antenna system

The present invention further increases the performance and capacity of the pre-lake and continuous orthogonal spreading code-based CDMA (Code Division Multiple Access) base station system, further improves the performance of the terminal, and realizes a practical adaptive beamforming system. The present invention relates to a CDMA array antenna system and a method for providing a forward, reverse link automatic beamforming function using an array antenna.

In order to process L multipaths, a conventional RAKE receiver required L matched filters and a searcher. However, a pre-lake system is transmitted through a pre-lake combiner based on channel information at a transmitter, and a receiver receiving the receiver needs only one matched filter to extract one peaked signal. This pre-lake method has a much simpler structure than a conventional rake receiver. However, the L path signal transmitted due to the rake effect becomes 2 L -1 paths through the channel, and finally, the received signal has multiple access interference (MAI) and multipath interference (MPI). Path Interference) is about doubled. Because of this, the pre-lake system is significantly affected by the amount of interference that changes as the number of multipaths increases, and the performance of about 2 times the interference is lower than when using a rake receiver. This is due to the poor orthogonality of existing Walsh codes.

On the other hand, in the pre-lake-based system, the reception performance is inferior to the conventional rake receiver due to the effects of channel fading and interference, and the performance deterioration by the number of users is more severe. In order to overcome this problem, a method of overcoming interference and improving reception performance by introducing a multi-antenna technique in a pre-lake based system has been proposed.

Multi-antenna technology has been a key to the rapid development of mobile communication technology by greatly increasing the reception performance and data rate. The antenna system reduces the effects of major disturbances in mobile communication, which are summarized as fading, delay spread, and co-channel interference. Multi-antenna systems include beamforming and spatial diversity. In recent years, as the demand for high quality, wideband data communication is increasing, the frequency resource used in the mobile communication is expected to be insufficient. The method is paying attention. In particular, a smart antenna that adaptively adjusts the beam pattern is mainly used.

There are 3G WCDMA, WiMAX, and other systems using this multi-antenna technology, and they will be actively researched and used in 4G communication systems in the future. However, the fundamental interference problem of wireless communication in the wireless communication will be further exacerbated by the increase of the downtown area and the increase in the number of users. Commercially available CDMA systems, IS-95 and IMT-2000 systems, are also exposed to various interference environments that degrade system performance. The pre-lake-based beamforming CDMA scheme may also be implemented in a concise hardware scheme, but has a limitation in that performance degradation due to interference occurs.

An object of the present invention is to improve the performance and capacity of the pre-lake and continuous orthogonal spreading code-based CDMA array antenna system for interference-free communication, so that it can be widely applied to various advanced wireless mobile communication applications. An apparatus and method for beamforming transmission / reception at a chip level or symbol level based on multiple antennas on a reverse link are provided.

In the present invention, an ultra-high performance CDMA array antenna wireless mobile communication system based on pre-lake and continuous orthogonal spreading codes for interference-free communication is considered, and a beamforming transmission / reception function and structure optimized for a given basic system to further improve performance Introduce.

In a communication system according to an aspect, a base station receiving a signal through a multipath channel using a plurality of antennas may include a plurality of antennas for a plurality of pre-lake combined pre-lake composite signals received through the plurality of antennas. Beam matching unit for each user to perform chip level reception beamforming for the plurality of pre-lake synthesis signals by multiplying a weight vector corresponding to the group, and matching filtering the plurality of pre-lake synthesis signals on which reception beamforming is performed And a despreader for demodulating a plurality of user signals.

In a communication system according to another aspect, a terminal receiving a signal through a multipath channel using a plurality of antennas may include a plurality of antennas for a plurality of pre-lake combined pre-lake composite signals received through the plurality of antennas, respectively. A beam forming unit performing chip level reception beam shaping for a plurality of pre-lake synthesized signals by multiplying a weight vector corresponding to, and demodulating and demodulating a user signal of a terminal by performing matching filtering on the output signal after the reception beam shaping is performed. It includes a despreading unit.

According to another aspect, a base station receiving a signal through a multipath channel using a plurality of antennas may perform a matched filtering on a plurality of pre-lake combined pre-lake synthesized signals received through the plurality of antennas, thereby providing a plurality of users. A despreader for demodulating a signal and a beamforming unit for performing symbol level reception beam shaping for a plurality of user signals by multiplying a plurality of user signals by a weight vector corresponding to each of the plurality of antennas.

A terminal receiving a signal through a multipath channel using a plurality of antennas according to another aspect may match-filter the plurality of pre-lake combined pre-lake synthesized signals received through the plurality of antennas to the terminal. A despreader for demodulating the user signal, and a beamformer for performing symbol level reception beamforming on the user signal by multiplying the weight vector corresponding to each of the plurality of antennas by the user signal.

According to another aspect of the present invention, a method for receiving a signal transmitted through a multipath channel using a plurality of antennas in a base station comprises: a plurality of pre-lake combined pre-lake synthesized signals received through a plurality of antennas; Performing chip level reception beamforming for each of the plurality of pre-lake synthesis signals by multiplying a weight vector corresponding to each antenna, and matching filtering the plurality of pre-lake synthesis signals on which the reception beamforming is performed. Demodulating a plurality of user signals.

According to another aspect of the present invention, a method for receiving a signal transmitted through a multipath channel using a plurality of antennas in a base station includes: matching and filtering a plurality of pre-lake combined pre-lake synthesized signals received through a plurality of antennas Demodulating a plurality of user signals, and multiplying a plurality of user signals by a weight vector corresponding to each of the plurality of antennas to perform symbol beam reception on the plurality of user signals for each user.

In a communication system according to another aspect, a base station transmitting a signal using a plurality of antennas may spread and modulate a user signal by using a continuous orthogonal spreading code having orthogonality continuously for a predetermined time interval for each user. Multiplying the spreading unit to generate a pre-lake combining signal, and generating a pre-lake synthesis signal by multiplying the pre-lake synthesis signal by a weight vector corresponding to each of the plurality of antennas. It includes a beam forming unit for performing the transmission beam forming of.

As described above, the present invention increases the performance and capacity of the system by providing a multi-antenna based chip level or symbol level beamforming transmission and reception apparatus and method in the forward and reverse links. Therefore, there is an advantage of realizing an ultra-high performance base station and a terminal which provide not only high hardware and power efficiency but also interference-free reception.

According to the present invention, when the pre-lake method and the continuous orthogonal spreading code are used, the CDMA system using the array antenna can be largely a simple structure. The pre-lake method significantly reduces the number of matching filters compared to the previous one, and the continuous orthogonal spreading code performs perfect interference cancellation to prevent deterioration due to the increase in the number of users.

Interference that has been eliminated through beamforming can be completely eliminated by spreading / despreading by a continuous orthogonal spreading code. This eliminates the inherent inherent MAIs and MPIs in wireless communications, and allows beamforming systems to achieve perfect array gains.

High hardware efficiency is achieved through pre-lake, and the interference cancellation capability of continuous orthogonal spreading codes provides optimal beamforming system performance, resulting in price competitiveness, miniaturization, and low power consumption at terminals and base stations. Etc. are possible.

This results in the outstanding performance of the entire CDMA beamforming system, as well as concise hardware structure and computational savings, making it a very effective system for reducing cost efficiency and power consumption. In particular, when the device is applied to the terminal, the device can solve the battery problem by miniaturization and low power through hardware simplicity.

Such high efficiency, economical efficiency and excellent performance at the same time can be used in various mobile wireless communication applications.

1 is a diagram illustrating a communication system according to an embodiment of the present invention.
2 is a view showing the configuration of a terminal capable of forming a beam of the MIMO method according to an embodiment of the present invention.
3 is a diagram illustrating a configuration of a transmitter when the terminal of FIG. 1 has a single antenna according to an embodiment of the present invention.
4 is a diagram illustrating an example of a configuration of a receiver of a base station for receiving a signal from a terminal by forming a reception beam at a chip level according to an embodiment of the present invention.
5 is a diagram illustrating a configuration of a receiver of a base station when channel estimation is performed when forming a chip level reception beam according to an embodiment of the present invention.
FIG. 6 is a diagram illustrating a configuration of a receiver of a base station for receiving and receiving a signal transmitted from a terminal at a symbol level according to an embodiment of the present invention.
7 is a diagram illustrating a configuration of a receiver of a base station in case of performing channel estimation when forming a symbol level reception beam according to an embodiment of the present invention.
8 is a diagram illustrating a configuration of a transmitter of a base station that transmits a signal to a terminal by forming a transmission beam in a forward case according to an embodiment of the present invention.
9 is a diagram illustrating a configuration of a receiver of a terminal capable of forming an MISO beam through a terminal using a single antenna according to an embodiment of the present invention.
FIG. 10 is a diagram illustrating a configuration of a receiver of a terminal having multiple antennas for chip-level MIMO beam shaping through multiple antennas according to an embodiment of the present invention.
FIG. 11 is a diagram illustrating a configuration of a receiver when channel estimation is performed in a terminal having multiple antennas forming chip level MIMO beams received through multiple antennas according to an embodiment of the present invention.
12 is a diagram illustrating a configuration of a receiver of a terminal capable of forming a symbol level MIMO beam received through a multiple antenna according to an embodiment of the present invention.
FIG. 13 is a diagram illustrating a configuration of a receiver of a terminal when channel estimation is performed when forming a symbol level reception beam according to an embodiment of the present invention.
14 is a flowchart illustrating a method of receiving a signal transmitted through a multipath channel using a plurality of antennas in a base station according to an embodiment of the present invention.
15 is a flowchart illustrating a method of receiving a signal transmitted through a multipath channel using a plurality of antennas in a terminal according to an embodiment of the present invention.
16 is a flowchart illustrating a method for receiving a signal transmitted through a multipath channel using a plurality of antennas in a base station according to another embodiment of the present invention.
17 is a flowchart illustrating a method of receiving a signal transmitted through a multipath channel using a plurality of antennas in a terminal according to another embodiment of the present invention.
18 is a flowchart illustrating a method for transmitting a signal through a multipath channel by using a plurality of antennas in a terminal according to an embodiment of the present invention.
19 is a flowchart illustrating a method of transmitting a signal through a multipath channel using a plurality of antennas in a base station according to an embodiment of the present invention.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, if it is determined that detailed descriptions of related well-known functions or configurations may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted. In addition, terms to be described below are terms defined in consideration of functions in the present invention, which may vary according to intention or custom of a user or an operator. Therefore, the definition should be based on the contents throughout this specification.

1 is a diagram illustrating a communication system according to an embodiment of the present invention.

The communication system 110 of FIG. 1 is a CDMA beamforming system using a pre-lake and a continuous orthogonal spreading code, and includes a terminal 110 and a base station 120.

The terminal 110 and the base station 120 may function as a transmitting device and a receiving device, respectively. The terminal 110 and the base station 120 may be connected through a multipath channel. The terminal 110 includes a transmitter 112 for transmitting a signal through an antenna and a receiver 114 for receiving a signal through an antenna. The base station 120 includes a transmitter 122 for transmitting a signal through an antenna and a receiver 124 for receiving a signal through an antenna.

In the reverse direction, the transmitter 112 of the terminal 110 spread-modulates an input signal (or a user signal) using a continuous orthogonal spreading code having a orthogonal characteristic continuously for a predetermined time interval, and then pre-lakes to combine the pre-lakes. A composite signal can be sent. The receiving unit 124 of the base station 120 may restore the input signal of the terminal 110 from the received signal after receiving the signal transmitted from the terminal 110 through a multipath channel. In this reverse reception beamforming, the base station 120 obtains a weight vector for forming a reception beam corresponding to the terminal 110 in order to efficiently receive the received signal of the terminal 110, and transmits the weight vector again in the forward direction. It can be used as it is or through modification at the time of beam formation.

Similarly, in the forward direction, the transmitter 122 of the base station 120 may spread-modulate the input signal using a continuous orthogonal spreading code and then pre-lake combine to transmit the pre-lake combined signal. The receiving unit 114 of the terminal 110 may restore the input signal of the base station 120 from the received signal after receiving the signal transmitted from the base station 120 through the multi-path channel. Techniques for pre-lake and continuous orthogonal spreading codes are described in detail in a previously registered patent (application number: 10-2007-0042510).

According to an embodiment of the present invention, the conventional Walsh code loses orthogonality when synchronization is not synchronized, and thus large degradation occurs. According to an embodiment of the present invention, continuous orthogonal spreading has perfect continuous orthogonal spreading characteristics between received signals within a predetermined chip interval. Use a spreading code.

The continuous orthogonal spreading code is a spreading code having orthogonal characteristics continuously for a predetermined time interval, and the autocorrelation value and the cross-correlation value may be 0 for a predetermined time interval. Here, the predetermined time interval may be a length that can cover the main delay path length of the multipath interference. The continuous orthogonal spreading code may include multi-phase and multi-level continuous orthogonal codes. The continuous orthogonal spreading code may include any one of a zero correlation duration (ZCD), a zero correlation zone (ZCZ), a large area synchronous (LAS), and the like. Such continuous orthogonal spreading codes can be used in place of Walsh codes to eliminate interference such as multiple access interference (MAI) and multi-path interference (MPI). MAI stands for multi-access interference, ie multi-user interference, and MPI stands for multipath interference, ie self-interference.

The terminal 110 may include N antennas, and the base station 120 may include M antennas. N is a natural number of 1 or more, and M is a natural number of 2 or more. If the number of antennas of the terminal 110 is two or more, MIMO (Multiple Input Multiple Output) beamforming system is possible, and in the case of one, SIMO (Single Input Multiple Output) and MISO (Multiple Input Single Output) beamforming system are implemented. Can be.

That is, in the reverse direction from the terminal 110 to the base station 120, a beamforming system of SIMO and MIMO may be implemented. In the forward direction from the base station 120 to the terminal 110, beamforming of MISO and MIMO is performed. The system can be implemented.

N antennas of the terminal 110 may be understood as one component of the transmitter 112 and the receiver 114. Similarly, the M antennas of the base station 120 may be understood as one component of the transmitter 122 and the receiver 124.

In the case where the base station 120 is a multi-antenna system and the terminal 110 is a single antenna system, the signal flows in the reverse direction and the forward direction are as follows.

1. Reverse Signal Flow

First, a signal flow is described as an equation for the reverse direction from the terminal 110 to the base station 120 as follows.

가 기지국(120)의 다중 안테나로 수신 빔 형성을 통하여 수신된 신호

는 수학식 1과 같다.Signal transmitted from the terminal 110

Received through shaping beams to multiple antennas of base station 120

Is the same as Equation 1.

는 기지국(120)의 각 안테나에서 발생된 백색 잡음 벡터이다.

및

은 각각 사용자 신호(또는 데이터 심볼)들이 각각 채널을 거쳐서 경로에 따라 달라지는 진폭(또는 경로 이득)과 위상을 나타낸다. K 는 통신 시스템 내의 총 사용자 수를 나타내고, L 은 통신 시스템 내의 총 경로 수를 나타낸다.

는 기지국(120)의 각 안테나 소자들에 들어오는 수신 신호들마다 다른 수신 시점의 차이에 의해 발생되는 벡터이다. 수신 시점의 차이는 지연시간으로 표현이 가능하며, 이로 인해 기지국(120)의 각 안테나로 들어가는 신호들 사이에는 위상 차이가 발생된다. T _c 는 확산 부호의 1칩 구간에 해당한다. In Equation 1

Is a white noise vector generated at each antenna of the base station 120.

And

Represent each of the amplitudes (or path gains) and phases of the user signals (or data symbols) as they pass through the channels, respectively. K represents the total number of users in the communication system, and L represents the total number of paths in the communication system.

Is a vector generated by a difference in reception time for each of the received signals input to each antenna element of the base station 120. The difference in reception time can be represented by a delay time, which causes a phase difference between signals entering each antenna of the base station 120. T _c corresponds to one chip section of the spreading code.

로 일반화되어 표현될 수 있다.This is an array response vector (Array Response or Array Steering Vector) of the k th user, the l th path, as shown in Equation 2 below.

Can be generalized to

The antenna spacing d is λ / 2 like a normal beamforming system. λ is the wavelength of the signal.

를 계산하여 결정할 수 있다. 결정된 가중치 벡터는 수신 신호

에 곱해져서 수신 빔 형성이 수행될 수 있다. The base station 120 extracts a portion to be compared with a reference signal in Equation 1 above, and a weight vector through a beamforming algorithm together with the reference signal.

Can be determined by calculating The determined weight vector is the received signal

The receive beamforming can be performed by multiplying by.

Equation 3 is a signal before despreading by a matched filter (not shown) of the receiver 122 of the base station 120.

칩 타임에 정합필터가 확산코드

를 발생시켜 역확산이 이루어진다. In inverse conversion, ( L -1), which is the point where the peak signal exists for the user k received signal.

Matching filter spreads code at chip time

Despreading is done by generating.

In order to obtain a weight vector, a reference signal is required. In the case of TDD, the following midamble is used. This is already known to the receiver 124 of the base station 120, it can be expressed as shown in Equation 4.

와

에서의 (L - 1)의 의미는 사용자 k 수신 신호에 대해 피크 신호가 존재하는 시점인 (L - 1)

칩 타임에 기준신호(미드앰블)를 발생시킨다는 것을 의미한다. 여기서 다중 경로는 통상 총 L 개의 경로로 가정하며, 경로 인텍스는 l = 0, 1, ... , L - 1 로 표시하기 때문에 실제로 (L - 1)

칩 타임은 L 번째 칩 타임이라 할 수 있다.

는 미드앰블의 동상 성분을 나타내고,

는 미드앰블의 직교 위상 성분을 나타낸다.
here,

Wow

(L - 1) in the meaning of a point in time at which the peak signal is present for a user k the received signal (L - 1)

This means that a reference signal (midamble) is generated at chip time. Multipath is typically assumed to be a total of L paths, and since the path index is represented by l = 0, 1, ..., L -1, it is actually ( L -1)

The chip time may be referred to as the L th chip time.

Represents the in-phase component of the midamble,

Represents the quadrature phase component of the midamble.

2. Forward direction  Signal flow

Next, the flow of signals in the forward direction from the base station 120 to the terminal 110 is described as follows. The signal z (t) transmitted from the multiple antennas through the transmission beamforming in the base station 120 is represented by Equation 5 below.

는 사용자 k 송신 신호에 대한 가중치 벡터의 켤레(Conjugate) 값 벡터이다. 순방향의 가중치 벡터는. 역방향에서 구해진 가중치 벡터를 기반으로 결정되어 사용될 수 있다. here,

Is the conjugate value vector of the weight vector for the user k transmit signal. The weight vector in the forward direction is It may be determined and used based on the weight vector obtained in the reverse direction.

As a method of determining the weight vector in the forward direction, there may be various methods such as using the weight vector obtained in the reverse direction as it is or using the weight vector obtained in the reverse direction after inverse matrix transformation. A conceptual system invention encompasses all methods. The important thing here is to normalize so that the norm of the weight vector is always 1. This ensures that the transmission signal to noise ratio (SNR) is maintained. This is shown in Equation 6 below.

When Equation 6 is performed, only the magnitude value is normalized to 1 while maintaining the phase of the weight vector. This normalized weight vector is used.

Z (t) of Equation 5 represents a multi-user signal from the multiple antennas, and the signal r _i (t) received by the terminal 110 having the single antenna of the i-th user is expressed as Equation (7).

는, 사용자 i의 단말(110)의 l번째 경로의 배열 응답 벡터를 나타낸다.

및

는 각각 데이터 심볼들이 각각 채널을 거쳐서 경로에 따라 달라지는 진폭(또는 경로 이득)과 위상을 나타낸다.The signal r _i (t) is a signal of the user i before despreading by a matching filter (not shown) included in the receiving unit 114 of the terminal 110.

Denotes an array response vector of the l-th path of the terminal 110 of the user i.

And

Denotes the amplitude (or path gain) and phase of each data symbol that varies from path to path through each channel.

의 칩 타임에 동기화된 확산코드

를 발생시켜 역확산을 수행할 수 있다.
In inverse conversion, a matched filter (not shown) that performs despreading is the point ( L -1) at which the peak signal exists for the user k received signal.

Spread Code Synchronized to Chip Time

Despreading can be performed by generating.

Hereinafter, an operation method and features of the communication system 100 according to an exemplary embodiment will be described according to a flow from the reverse direction to the forward direction.

2 to 7 show an example of the configuration of the terminal 110 and the base station 120 for the reverse signal transmission in the communication system 100.

2 is a diagram illustrating a configuration of a terminal 110 capable of forming a beam using a MIMO scheme according to an embodiment of the present invention.

The transmitter 112A of the terminal 110 of FIG. 2 may transmit a signal to the base station 120 through transmission beamforming using multiple antennas. In this case, both the transmission beamforming in the terminal 110 and the reception beamforming in the base station 120 occur. That is, reverse MIMO beam formation is possible.

The transmitter 112A includes a normalizer 205, a diffuser 210, a pre-lake synthesizer 220, a beam former 230, a weight vector switcher 240, a weight vector generator 250, and a plurality of them. RF transceivers 260-1 to 260-N and array antennas 265-1 to 265-N consisting of a plurality of antennas.

The normalization unit 205 normalizes the data string b _k , which is a user signal of the user k to be transmitted, with a normalization factor Q. The data string of user k (b _k ) is a signal whose original user data is primarily modulated by various digital modulation schemes such as phase shift keying (PSK), quadrature phase shift keying (QPSK), quadrature amplitude modulation (QAM), and the like. Can be.

The spreader 210 spread-modulates a user signal to be transmitted using a continuous orthogonal spreading code to generate a spread signal. The spreader 210 may include a continuous orthogonal code generator 212 that generates a continuous orthogonal spreading code, and a multiplier 214 that multiplies the signal b _k to be transmitted.

The pre-lake synthesis unit 220 pre-lake combines the spread modulated spread signal to generate a pre-lake synthesized signal. In other words, the pre-lake synthesis unit 220 obtains channel information in the previous transmission / reception process to the spread-modulated spread signal, and combines the channel impulse response for the multipath channel based on the converted information into a pre-lake synthesized signal. will be. In this case, combining the channel impulse response means applying a complex conjugate value of the inverted value of the channel impulse response to the spread signal.

The beam former 230 multiplies the weight vector provided by the weight vector switcher 240 by the pre-lake synthesized signal to form a chip level transmission beam.

The RF transceivers 260-1 to 260 -N may modulate the signal on which the transmission beamforming is performed at a carrier frequency. When the signal is transmitted through the RF transceivers 260-1 to 260 -N, the signal is obtained through the channel to obtain a peak signal having a RAKE effect. In the receiver 114 of the base station 120 of FIG. 1, only one matched filter for obtaining the L− 1 th center signal having a RAKE effect is required. For this reason, in the receiver (or base station 120) that receives the signal transmitted by the transmitter 112A of the terminal 110, when the weight vector is obtained at the time of forming the reception beam, the reference signal generation time point of Equation 4 is L A reference signal synchronized with the received signal of the -1th path may be used. That is, the reference signal as in Equation 4 is used to obtain a weight vector corresponding to the peak path as in Equation 3.

The weight vector converting unit 240 provides a weight vector to be applied to the beam forming unit 230. The weight vector switcher 240 may provide the beam vector 230 with the weight vector provided by the weight vector generator 250. The weight vector generator 250 is a weight vector generator (eg, described later) included in the base station 120 in a previous communication process, that is, for example, in a previous transmission and reception process with the base station 120 of FIG. 1. In the previous transmission and reception process of FIGS. 4 and 5, the weight vector generators 430 and 530-1 to 530 -N may be used to use the weight vector obtained through the base station 120.

The use of the weight vector is a method of using a weight vector obtained in a previous time slot during a certain time slot interval, and converting a weight vector expected by a predetermined method based on a previously obtained weight vector to a weight vector of the next interval. There is a method, a method of directly using the weight vector obtained in the current time slot, and the present invention encompasses all methods in the technical spirit of these methods. The operation of the weight vector converting unit 240 may be determined according to which of the various methods is used.

3 is a diagram illustrating a configuration of a transmitter when the terminal 110 of FIG. 1 has a single antenna according to an embodiment of the present invention.

The transmitter 112B of FIG. 3 includes a normalizer 305, a diffuser 310, a pre-lake synthesizer 320, an RF transceiver 330, and a single antenna 335.

Normalization section 305 normalizes the user passes the signal (b _k) of user k to be transmitted to a normalization factor (Q) and qualified user signal to spreading section 310. The In the spreader 310, the continuous orthogonal code generator 312 generates a continuous orthogonal spreading code, and the multiplier 314 multiplies the user signal to be transmitted by the generated continuous orthogonal spreading code, and spreads and modulates the user signal. Generate a spread signal. The spreader 310 transmits the generated spread signal to the pre-lake synthesizer 320.

The pre-lake synthesis unit 320 converts the spread modulated spread signal into a pre-lake synthesized signal. The pre-lake synthesized signal is transmitted via a single antenna 335 via the RF transceiver 330.

In this case, the base station 120 may receive a signal transmitted from the transmitter 112B of the terminal 110 by receiving a beam. In this case, SIMO beam formation is possible.

4 is a diagram illustrating an example of a configuration of a receiver of a base station 120 that receives a signal from a terminal 110 by forming a reception beam at a chip level according to an embodiment of the present invention.

The receiving unit 124A of the base station 120 of FIG. 4 is configured to receive and transmit a signal transmitted by the transmitter 112A or the transmitter 112B of the terminal 110 shown in FIGS. 2 and 3 at the chip level. Can be. Referring to FIG. 4, the receiver 124A of the base station 120 includes an array antenna 401-1 to 401-M including a plurality of antennas, a plurality of RF transceivers 405-1 to 405 -M, and a beam forming unit. 410, a first demultiplexer 420, a plurality of weight vector generators 430-1 to 430 -K, a plurality of reference signal generators 440-1 to 440 -K, and a plurality of second inverses The multiplexing units 450-1 to 450 -K and a plurality of despreading units 460-1 to 460 -K are included. The beam forming unit 410 may include a plurality of beam forming units 410-1 to 410 -K. A plurality of beam forming units 410-1 to 410-K, weight vector generators 430-1 to 430-K, reference signal generators 440-1 to 440-K, and a plurality of second demultiplexers 450-1 to 450-K and the plurality of despreading units 460-1 to 460-K may be formed to correspond to the total number of users of the communication system.

The pre-lake combined pre-lake combined signal from the terminal 110 is received at each of the antennas 401-1 through 401-M via a multipath channel. Each signal received by each of the antennas 401-1 through 401-M is input to the RF transceivers 405-1 through 405-M. The RF transceivers 405-1 through 405-M may convert each signal received by the array antennas 401-1 through 401-M into a baseband signal.

The plurality of beam formers 410-1 to 410 -K multiplies the received signals received through the respective RF transceivers 405-1 to 405 -M by a weight vector, thereby providing a chip level for the received pre-lake synthesized signal. Receive beamforming is performed for each user (ie, each terminal). The signal before the weight vector is multiplied may be expressed as in Equation 1.

The weight vector generators 430-1 to 430-K of FIG. 4 generate beamforming vectors for each user according to a beamforming algorithm, and provide the beamforming vectors to the plurality of beamforming units 410-1 to 410 -K. The weight vector generators 430-1 through 430 -K typically reference signals and reference signal generators 440 extracted from signals received by the antennas 401-1 through 401-M through channels, for each user. A weight vector for an object may be obtained through an algorithm operation with the original reference signal generated at. The first demultiplexer 420 may typically extract the reference signal portion from the signals received by the array antennas 401-1 through 401-M through a channel.

In general, a midamble is used for a time division duplex (TDD) as a reference signal, and a pilot signal may be used for a frequency division duplex (FDD). As shown in FIG. 4, if the number of antennas is M, the weight vector is a vector of M × 1.

In the case of a TDD system, a flow of obtaining a weight vector is as follows. The received signals converted into baseband signals by the plurality of RF transceivers 405-1 through 405 -M are demultiplexed by each of the midamble parts by the first demultiplexer 420, thereby weighting the vector generator 430. Enter In the weight vector generator 430, there is a beamforming algorithm through which the weight vector is calculated.

Beamforming algorithms include Optimal and Sub-optimal methods, and in other respects, reference signal-based beamforming methods, and specifically, Minimum Mean Square Error (MMSE), Normalized Least Mean Square (NLMS), and Least Mean (LMS). Square) and RLS (Recursive Least Square). These algorithms have their own characteristics, but in common they consider the signals of other users as interference, suppress them, and generate weight vectors for beamforming in order to have an array gain in receiving the desired target user's signals.

All beamforming algorithms without departing from the spirit of the overall system of the present invention fall within the scope of the present invention. The use of the weight vector is a method of using a weight vector obtained in a previous time slot during a certain time slot interval, a method of converting a weight vector of the next interval based on a previously obtained weight vector, and using the weight vector in a current time slot. There exists a method of directly using the obtained weight vector, and the present invention encompasses all methods in the technical spirit of these methods.

As described above, the received signals passing through the RF transceivers 405-1 to 405-M in the beam forming unit 410 are multiplied by the weight vector for each array. In the beam forming unit 410, the signals of each array multiplied by the weight vector are added to each other, which is expressed by Equation 3 below.

The signal of Equation 3 is input to the second demultiplexers 450-1 to 450 -K, and user data excluding the reference signal (or midamble) from the second demultiplexers 450-1 to 450 -K. The portion is extracted and enters the despreader 460. The despreader 460 demodulates the plurality of user signals by matched filtering the plurality of pre-lake synthesized signals on which the reception beamforming is performed.

To this end, the despreader 460 may include a plurality of matching filters 460-1 through 460 -K to process the received signal received through each antenna. Each of the plurality of matching filters 460-1 through 460 -K may be configured such that the reference signal is matched to a code having a section corresponding to one code period. Each of the plurality of matched filters 460-1 through 460 -K demodulates a plurality of user signals by performing matched filtering on the L −1th signal, respectively.

The plurality of determination units 470-1 to 470 -N may determine a signal output from each of the matching filters 460-1 to 460 -K and output a user data string b _k sent from the terminal 110. have.

5 is a diagram illustrating a configuration of a receiver of the base station 120 in the case of performing channel estimation when forming a chip level reception beam according to an embodiment of the present invention.

Referring to FIG. 5, the receiver 124B of the base station 120 includes an array antenna 501-1 to 501-M, a plurality of RF transceivers 505-1 to 505-M, and a plurality of antennas including a plurality of antennas. Beam forming units 510-1 to 510-K, first demultiplexer 520, weight vector generators 530-1 to 530-K, and reference signal generators 540-1 to 540-K ), A plurality of second demultiplexers 550-1 through 550-K, a plurality of despreaders 560-1 through 560-N, and a plurality of channel estimators 570-1 through 570-K. Include.

The receiver 124B of the base station 120 of FIG. 5 is similar to the configuration of the receiver 124A of the base station 120 of FIG. 4 except for the modified configuration in which the channel estimator 570 is included. To this end, the plurality of second demultiplexers 550-1 to 550 -K outputs a user data portion excluding the reference signal from the received signal to the despreaders 560-1 to 560 -K, and a multiplier. 545 may be configured to output a portion of the reference signal in the received signal.

The plurality of reference signal generators 540-1 to 540 -K generate a plurality of reference signals synchronized with the received signal of the L-1 th path among the plurality of pre-lake combined signals received for each user. Each reference signal generated by the plurality of reference signal generators 540-1 through 540-K enters the plurality of channel estimators 580-1 through 580-K through the multiplier 545, respectively. Each of the plurality of channel estimators 580-1 through 580-K includes a reference signal portion of the received signal through the channel and the L-1th path generated by the reference signal generators 540-1 through 540 -K. The channel is estimated for each user with a reference signal synchronized to the received signal. Estimation methods may vary, and the present invention includes all estimation methods as a comprehensive system invention, rather than being dependent on the method.

The user data portion of the received signal output from each matched filter 560-1 through 560-K is corrected using the channel estimated value and then determined by the determination units 570-1 through 570-K. The channel estimators 580-1 to 580-K and the component parts for the reference signal processing for channel estimation may be selectively used.

FIG. 6 is a diagram illustrating a configuration of a receiver of a base station 120 that receives and receives a signal transmitted from a terminal 110 at a symbol level according to an embodiment of the present invention.

The receiving unit 124C of the base station 120 of FIG. 6 is configured to receive a plurality of pre-lake combined pre-lake combined signals sent by the terminal 110 illustrated in FIGS. 2 and 3 by forming a reception beam at a symbol level. . The receiver 124C of the base station 120 of FIG. 6 includes an array antenna 601-1 to 601-M including a plurality of antennas, a plurality of RF transceivers 605-1 to 605 -M, and a plurality of demultiplexers. 610-1 to 610 -M, the despreader 620, the plurality of beam forming units 630-1 to 630 -K, the plurality of weight vector generators 640-1 to 640 -K, and the plurality of Reference signal generators 650-1 through 650-K and a plurality of determination units 660-1 through 660-K. A plurality of beam forming units 630-1 to 630-K, a plurality of weight vector generating units 640-1 to 640-K, reference signal generating units 650-1 to 650-K, and a plurality of determining units ( 660-1 to 660-K may be formed as many as the total number of users of the communication system.

For the symbol level beam forming, as shown in FIG. 4, the chip level passed through the beam forming units 410-1 to 410 -K and then despread by the despreading units 460-1 to 460 -K is shown. In contrast to a signal processing process for beamforming of a plurality of signals, first, a plurality of pre-lake synthesized signals are despread by the despreader 620 and then a symbol for each user by the beam formers 630-1 to 630 -K. There is a difference in that the level of reception beamforming is performed. In this way, the processing flow order of the signal is changed, but the operation and the equations applied are the same.

Referring to FIG. 6, a plurality of pre-lake synthesized signals received through the RF transceivers 605-1 through 605-M are stored in the user data portion through the demultiplexers 610-1 through 610 -M of each array. Are separated. Thereafter, the user data portions are each despread in the despreader 620 through the successive orthogonal spreading codes. The despreader 620 includes matching filters (620-11 to 620-1K, ..., 620-M1 to 620-MK) of each array for performing despreading. Matching filters 620-11 to 620-1K, ..., 620-M1 to 620-MK perform matching filtering in synchronization with the signal of the L -first path according to the characteristics of the pre-lake system. Despread the data portion.

Also, the demultiplexers 610-1 to 610 -M transmit the reference signal portion of the received signal to the weight vector generators 640-1 to 640 -K. The weight vector generators 640-1 to 640 -K may include reference signals received from the demultiplexers 610-1 to 610 -M and L − generated from the reference signal generators 650-1 to 650 -K. A weight vector is generated through a specific beamforming algorithm using a reference signal synchronized with the signal of the first path.

When the weight vector is generated, the beam forming unit 630 may despread the user data portion of the symbol level despread by each of the matching filters 620-11 through 620-1K and 621-M1 through 620-MK of the despreader 620. Are multiplied by the weight vector to perform symbol beam reception. After that, the pieces of user data calculated for each array are added to each signal.

The weight vector generators 640-1 to 640-K use a weight vector obtained in a previous time slot during a predetermined time slot interval, and convert the weight vector generator 640-1 into a weight vector of the next interval based on the previously obtained weight vector. The method of using, the method of directly using the weight vector obtained in the current time slot, etc. can be used, and the present invention encompasses all methods in the technical spirit of these methods.

The signal in which the reception beam shaping at the symbol level is performed by the beam forming units 630-1 to 630-K is determined by the plurality of determination units 660-1 to 660-K, and is outputted.

7 is a diagram illustrating a configuration of a receiver of the base station 120 in the case of performing channel estimation when forming a symbol level reception beam according to an embodiment of the present invention.

The receiver 124D of the base station 120 of FIG. 7 includes an array antenna 701-1 to 701-M including a plurality of antennas, a plurality of RF transceivers 705-1 to 705 -M, and a plurality of demultiplexers. 710-1 to 710 -M, the despreader 720, a plurality of beam forming units 730-1 to 730 -K, a plurality of weight vector generators 740, and a plurality of reference signal generators 750. -1 to 750-K), a plurality of determination units 760-1 to 760-K, and a plurality of channel estimating units 770-1 to 770-K.

The receiving unit 124D of the base station 120 of FIG. 7 includes a plurality of channel estimating units 770-1 to 770 -K so that the receiving unit 124C of the base station 120 of FIG. 6 is modified. Similar to the configuration.

The channel estimators 770-1 to 770 -K extract reference signal portions from the signals on which reception beamforming is performed by the beam forming units 730-1 to 730 -K, respectively, and extract the extracted reference signal portions and the reference. A channel is estimated for each user with a reference signal synchronized with the received signal of the L-1 th path from the signal generators 750-1 to 750-K. Estimation methods may vary, and the present invention includes all estimation methods as a comprehensive system invention, rather than being dependent on the method.

The channel state estimated by the channel estimating units 770-1 through 770-K is applied to the signal on which the reception beam forming is performed by the beam forming units 730-1 through 730-K, and thus the signal on which the receiving beam forming is performed. After the channel compensation is performed, the output signal may be output through the determination units 760-1 to 760 -K.

8 to 13 show an example of the configuration of the terminal 110 and the base station 120 for forward signal transmission.

8 is a diagram illustrating a configuration of a transmitter of a base station 120 that transmits a signal to a terminal 110 by forming a transmission beam in a forward direction according to an embodiment of the present invention.

As described above, in the forward direction, in FIG. 1, MISO and MIMO beamforming may be performed from the base station 120 of the multiple antennas to the terminal 110 that is a single antenna or multiple antennas.

The transmitter 212 of the base station 120 of FIG. 8 includes a plurality of normalizers 805-1 to 805 -K, a plurality of spreaders 810-1 to 810 -K, and a plurality of multiplexers 820-1 to 820-K), a reference signal generator 830, a plurality of pre-lake synthesis units 840-1 to 840-K, a beam forming unit 850, a weight vector switching unit 860, a weight vector generator ( 870, a plurality of RF transceivers 880-1 through 880 -M, and array antennas 885-1 through 885 -M.

The plurality of spreading units 810-1 to 810 -K spread the user data to be transmitted, respectively, with a continuous orthogonal spreading code for each user to generate a spread signal.

The multiplexers 820-1 to 820 -K multiplex each user's reference signal generated by the reference signal generator 830 and signals of the user data portion for each user, and output a single signal for each user. .

The plurality of pre-lake synthesis units 840-1 to 840 -K pre-lake combine the multiplexed signal for each user to generate a pre-lake synthesized signal.

The beam forming unit 850 multiplies the weight vectors provided by the weight vector converting unit 860 with each pre-lake synthesized signal to perform chip level transmission beam shaping for each user. The weight vectors may be determined by each receiving terminal 110 transmitted from the base station 120 and obtained from the terminal 110.

If the signals output from the plurality of pre-lake synthesis units 840-1 to 840-K are s _k (t), then the weight vector is multiplied by the antenna array through the beam forming unit 850, respectively. Is the same as (5). Signals z (t), multiplied by the conjugate values of the weight vector normalized by Equation 6, to signal s _k (t) are channeled through the RF transceivers 880-1 to 880-M of each array. Is sent.

The weight vector switcher 860 and the weight vector generator 870 may perform operations corresponding to the weight vector switcher 240 and the weight vector generator 250 of the terminal 120 of FIG. 2. However, the weight vector switching unit 860 may provide a weight vector to each pre-lake synthesis signal for each user, and the weight vector generator 870 generates a weight vector for each user to generate a weight vector switching unit ( In operation 860, a weight vector for each user may be provided.

The receiving device for receiving the signals z (t) may be a terminal having multiple antennas for forming the chip level reception beam of FIG. 10 or 11, or performing symbol level reception beam formation as shown in FIG. 12 or 13. It may be a terminal having multiple antennas. In addition, a terminal having a single antenna as shown in FIG. 9 may be used as a reception device for receiving signals z (t) for hardware efficiency and low power consumption of the terminal. The present invention encompasses all cases of a system having the same technical spirit without a separate definition of the number of antennas in a base station and a terminal.

9 is a view showing the configuration of the receiver 114 of the terminal 110 capable of forming the MISO beam through the terminal 110 using a single antenna according to an embodiment of the present invention.

The receiver 114A of the terminal 110 of FIG. 9 includes a single antenna 910, an RF transceiver 905, a matched filter 910, and a determiner 920.

When the signal is received by the terminal 110, which is a single antenna receiver shown in FIG. 9, through the multipath fading channel, the receiver 114A has one matched filter as in the above-described cases, because it has a pre-lake effect. It only needs to have 910.

On the other hand, the signal received by one receiving apparatus in a specific direction is a signal in which the signals transmitted from each of the array antennas of the transmitting apparatus are combined. Therefore, there is a time difference for each signal transmitted from each antenna according to the antenna direction of the receiving device, which indicates a phase difference. This is called an array response, and this vector value is multiplied by the signals transmitted for each antenna. Thus, the signal received by the receiving device in a particular direction is a signal that is multiplied by a specific array response and has experienced a multipath channel. Equation regarding this is shown in Equation (7). Since Equation 7 assumes that the reception device has a single antenna, white noise rather than a vector value is added, and the received signal is despread through the continuous quadrature spreading code in the matching filter 910 of the receiver 114A.

FIG. 10 is a diagram illustrating a configuration of a receiver of a terminal 110 having multiple antennas for chip-level MIMO beam shaping through multiple antennas according to an embodiment of the present invention.

Referring to FIG. 10, the receiver 114B of the terminal 110 includes an array antenna 1001-1 to 1001-N including a plurality of antennas, a plurality of RF transceivers 1005-1 to 1005-M, and a beam forming unit. 1010, the first demultiplexer 1020, the weight vector generator 1030, the reference signal generator 1040, the second demultiplexer 1050, the despreader 1060, and the determiner 1070. It includes.

A plurality of pre-lake synthesized signals transmitted from the base station 120 is received at each array antenna (1001-1 to 1001-M) through a multipath channel, after passing through the RF transceiver (1005-1 to 1005-M) It is input to the beam forming unit 1010.

The beam forming unit 1010 multiplies a received signal received through each RF transceiver 1005-1 through 1005-N by a weight vector to perform chip level reception beam shaping for the terminal 110. The signals of each array multiplied by the weight vector are added to each other and output to the second demultiplexer 1050.

The weight vector generator 1030 may generate a beamforming vector and provide it to the beamformer 1010 according to a beamforming algorithm. The weight vector generator 1030 typically includes a reference signal extracted from a signal received from each of the antennas 1001-1 through 1001-N through a channel and an L-1 th path generated by the reference signal generator 1040. With a reference signal synchronized to the received signal, a weight vector for the target may be obtained through algorithm calculation.

In general, a midamble is used for a time division duplex (TDD) as a reference signal, and a pilot signal may be used for a frequency division duplex (FDD). As shown in FIG. 10, if the number of antennas is N, the weight vector is a vector of N × 1.

In the case of a TDD system, a flow of obtaining a weight vector is as follows. After each signal received by the array antennas 1001-1 through 1001-M passes through the RF transceivers 1005-1 through 1005-M, the first demultiplexer 1020 demultiplexes only each midamble portion. And enters the weight vector generator 1030. Within the weight vector generator 1030 there is a beamforming algorithm through which the weight vector is calculated.

The second demultiplexer 1050 extracts a portion of the user data excluding the midamble from the received beamforming signal output from the beamformer 1010, and extracts the extracted user data portion to the L −1th signal. The synchronization is entered into the despreading unit 1060 and despread. The despreader 1060 may be a matched filter configured to match-filter the received signal with respect to the L −1 th signal.

The determination unit 1070 may determine the signal output from the matching filter 1060 and output the user data string b _k sent from the base station 120.

FIG. 11 is a diagram illustrating a configuration of a receiver 114 when performing channel estimation of a terminal 110 having multiple antennas for chip-level MIMO beam shaping through multiple antennas according to an embodiment of the present invention. .

Referring to FIG. 11, the receiver 114C of the terminal 110 includes array antennas 1101-1 to 1101-N, a plurality of RF transceivers 1105-1 to 1105-N, a beam forming unit 1110, and a first antenna. 1 demultiplexer 1120, weight vector generator 1130, reference signal generator 1140, second demultiplexer 1150, despreader 1160, determiner 1170 and channel estimator ( 1180).

The receiver 114C of the terminal 110 of FIG. 11 is similar to the configuration of the receiver 114B of the terminal of FIG. 10 except for a modified configuration in which the channel estimator 1180 is included. In addition, the second demultiplexer 1150 outputs the user data portion excluding the reference signal from the received signal to the despreader 1160, and the multiplier 1145 outputs the reference signal portion from the received signal. Can be.

Each reference signal synchronized with the received signal of the L-1 th path generated by the reference signal generator 1140 enters the channel estimator 1180 through the multiplier 1145. The channel estimator 1180 may generate a channel using the reference signal portion output from the second demultiplexer 1150, which is a reference signal portion of the received signal, and the reference signal generated by the reference signal generator 1140. Estimate. Estimation methods may vary, and the present invention includes all estimation methods as a comprehensive system invention, rather than being dependent on the method. The channel estimate value indicating the channel state estimated by the channel estimator 1180 may be applied to the user data portion output from the despreader 1160, and then output through the determiner 1170 after compensation is performed.

12 is a diagram illustrating a configuration of a receiver 114 of a terminal 110 capable of forming a symbol level MIMO beam received through multiple antennas according to an embodiment of the present invention.

The receiver 114D of the terminal 110 of FIG. 12 includes array antennas 1201-1 through 1201-N, a plurality of RF transceivers 1205-1 through 1205-N, and a plurality of demultiplexers 1210-1 through 1210. -N), a despreader 1220, a beam forming unit 1230, a weight vector generator 1240, a reference signal generator 1250, and a determiner 1260. The despreader 1220 includes a plurality of matched filters 1220-1 to 1220 -N.

In order to form the symbol level beam, as illustrated in FIG. 11, after the beam forming unit 1110 passes through, the despreading unit 1160 performs chip level beam forming in which the user signal of the terminal 120 is despread. In contrast to the signal processing process, the first signal is despread by the despreader 1220 so that the user signal of the terminal 120 is demodulated, and then the beamforming unit 1230 receives the beam forming. There is. In this way, the processing flow order of the signal is changed, but the operation and the equations applied are the same.

Referring to FIG. 12, the received signals passing through the RF transceivers 1205-1 to 1205-N are separated from the user data through the demultiplexers 1210-1 to 1210-N of each array. Thereafter, the user data portions are each despread through a successive orthogonal spreading code at despreader 1230. The matching filters 1220-1 through 1220 -N of each array performing despreading perform matching filtering on the user data portion in synchronization with the received signal of the L -1st path according to the characteristics of the pre-lake system. Perform diffusion.

In addition, the demultiplexers 1210-1 to 1210 -N separate a reference signal portion among the received signals and transmit the divided reference signals to the weight vector generator 1240. The weight vector generator 1240 is a specific beamforming algorithm using a reference signal received from the demultiplexer 1210 and a reference signal generated from the reference signal generator 1250 and synchronized with the received signal of the L-1 th path. The weight vector is generated through.

When the weight vector is generated, the beam forming unit 1230 is separated in each of the matching filters 1210-1 through 1220 -N of the despreading unit 1220, and multiplies the weight vector by each of the despread symbol level user data portions. Then, the data portion calculated for each array is added as one signal to perform beamforming at the symbol level.

The weight vector generator 1240 uses a weight vector obtained in a previous time slot during a predetermined time slot interval, converts the weight vector to a next weight vector based on the previously obtained weight vector, and uses the current weight vector. A method of directly using the weight vector obtained in the time slot can be used, and the present invention encompasses all methods in the technical spirit of these methods.

FIG. 13 is a diagram illustrating a configuration of a receiver when performing channel estimation of a terminal 110 capable of forming a symbol level MIMO beam received through a multiple antenna according to an embodiment of the present invention.

The receiver 114E of the terminal 110 of FIG. 13 includes array antennas 1301-1 through 1301-N, a plurality of RF transceivers 1305-1 through 1305-N, and a plurality of demultiplexers 1310-1 through 1310. -N), a despreader 1320, a beam forming unit 1330, a weight vector generator 1340, a reference signal generator 1350, a determiner 1360, and a channel estimator 1370.

The receiver 114E of the terminal 110 of FIG. 13 is similar to the configuration of the receiver 114D of the terminal 110 of FIG. 12 except for a modified configuration in which the channel estimator 1370 is included.

The channel estimator 1370 estimates the channel based on the reference signal portion of the received signal and the original reference signal from the reference signal generator 1350 through the channel. The channel state estimated by the channel estimator 1370 is applied to the signal on which the reception beamforming is performed by the beam forming unit 1330, and after the channel compensation is performed on the signal on which the reception beamforming is performed, the determination unit 1360. Can be output via

In the case of using a multi-antenna terminal as shown in FIGS. 10 to 13, since the terminal 110 receiving the signal transmitted by forming the transmission beam is subjected to the reception beam forming process through the weight vector generator and the beam forming unit, an array gain is obtained. The greater the greater the attenuation of interference. In addition, through the interference cancellation capability of the continuous orthogonal spreading code, even if the number of users increases, the degradation due to the interference can be almost eliminated.

14 is a flowchart illustrating a method of receiving a signal transmitted through a multipath channel using a plurality of antennas in a base station according to an embodiment of the present invention.

Base station 120 receives a plurality of pre-lake combined pre-lake combined signals via a plurality of antennas (1410). The plurality of pre-lake synthesized signals received by the base station 120 may be received from a terminal having multiple antennas as described with reference to FIG. 2 or from a terminal having a single antenna as described with reference to FIG. 3.

The base station 120 multiplies the received plurality of pre-lake synthesized signals by a weight vector corresponding to each of the plurality of antennas to perform chip level reception beam shaping for each of the plurality of pre-lake synthesized signals for each user (1420). ). The base station 120 demodulates the plurality of user signals by despreading the plurality of pre-lake combined signals on which the reception beamforming is performed through matched filtering (1430).

The base station 120 may extract a reference signal portion from the signal on which the reception beamforming is performed, and estimate the channel using the extracted reference signal portion and the reference signal generated by the reference signal generator. The base station 120 may then correct the user data portion of the demodulated user signal using the channel estimate value by channel estimation.

15 is a flowchart illustrating a method of receiving a signal transmitted through a multipath channel using a plurality of antennas in a terminal according to an embodiment of the present invention.

The terminal 110 receives a plurality of pre-lake combined pre-lake combined signals through the plurality of antennas (1510). The plurality of pre-lake synthesized signals received by the terminal 110 may be received from a base station as described with reference to FIG. 8.

The terminal 110 multiplies the received plurality of pre-lake synthesized signals by a weight vector corresponding to each of the plurality of antennas to perform chip level reception beam shaping for the plurality of pre-lake synthesized signals (1520). The terminal 110 demodulates the user signal of the terminal 110 by despreading the plurality of pre-lake synthesized signals on which the reception beamforming is performed through matched filtering (1530).

The terminal 110 may extract a reference signal portion from the signal on which the reception beamforming is performed, and estimate the channel using the extracted reference signal portion and the reference signal generated by the reference signal generator. Then, the terminal 110 may correct the user data portion of the demodulated user signal by using the channel estimation value by channel estimation.

16 is a flowchart illustrating a method for receiving a signal transmitted through a multipath channel using a plurality of antennas in a base station according to another embodiment of the present invention.

Base station 120 receives a plurality of pre-lake combined pre-lake combined signals via a plurality of antennas (1610). The plurality of pre-lake synthesized signals received by the base station 120 may be received from a terminal having multiple antennas as described with reference to FIG. 2 or from a terminal having a single antenna as described with reference to FIG. 3.

The base station 120 demodulates the plurality of user signals by matched filtering the plurality of pre-lake combined pre-lake combined signals received through the plurality of antennas. The base station 120 multiplies a plurality of user signals by a weight vector corresponding to each of the plurality of antennas to perform symbol beam reception on a plurality of user signals for each user (1630).

The base station 120 extracts a reference signal portion from the signal on which the reception beamforming is performed, estimates a channel for each user by using the extracted reference signal portion and the reference signal generated by the reference signal generator, and for each user. The signal on which the reception beamforming is performed may be corrected using a channel estimation value by channel estimation.

17 is a flowchart illustrating a method of receiving a signal transmitted through a multipath channel using a plurality of antennas in a terminal according to another embodiment of the present invention.

The terminal 110 receives a plurality of pre-lake combined pre-lake combined signals through the plurality of antennas (1710). The plurality of pre-lake synthesized signals received by the terminal 110 may be received from a base station as described with reference to FIG. 8.

The terminal 110 demodulates and demodulates the user signal of the asset by performing matched filtering on the plurality of pre-lake combined pre-lake synthesized signals received through the plurality of antennas (1720). The terminal 110 multiplies a plurality of user signals by a weight vector corresponding to each of the plurality of antennas to perform symbol beam reception on the user signal of the terminal 110 in operation 1730.

The terminal 110 extracts a reference signal portion from the signal on which the reception beamforming is performed, estimates a channel using the extracted reference signal portion and the reference signal generated by the reference signal generator, and performs the reception beamforming. The signal may be corrected by using a channel estimation value by channel estimation.

18 is a flowchart illustrating a method for transmitting a signal through a multipath channel by using a plurality of antennas in a terminal according to an embodiment of the present invention.

The terminal 110 generates a spread signal by spread-modulating a user signal using a continuous orthogonal spreading code having a quadrature characteristic continuously for a predetermined time period (1810).

The terminal 110 pre-lake combines the spread signal and generates a pre-lake synthesized signal (1820).

The terminal 110 multiplies the pre-lake synthesized signal by a weight vector corresponding to each of the plurality of antennas to perform chip level transmission beam formation (1830).

19 is a flowchart illustrating a method of transmitting a signal through a multipath channel using a plurality of antennas in a base station according to an embodiment of the present invention.

The base station 120 generates a spread signal by spread-modulating a plurality of user signals by using a continuous orthogonal spreading code having an orthogonal characteristic continuously for a predetermined time interval for each user (1910).

Base station 120 pre-lake combines the spread signals to generate a pre-lake composite signal (1920).

The base station 120 multiplies the pre-lake synthesized signal by a weight vector corresponding to each of the plurality of antennas to perform chip-level transmit beamforming for each user (1930).

In the present invention, an example using such a time division duplex (TDD) is mainly given, but the scope of the present invention can be applied to a frequency division duplex (FDD) system in which the receiver channel information is fed back from the transmitter. Normally, TDD uses a midamble as a reference signal, whereas FDD uses a pilot.

One aspect of the present invention may be embodied as computer readable code on a computer readable recording medium. The code and code segments implementing the above program can be easily deduced by a computer programmer in the field. Computer-readable recording media include all kinds of recording devices that store data that can be read by a computer system. Examples of the computer-readable recording medium include ROM, RAM, CD-ROM, magnetic tape, floppy disk, optical disk, and the like. The computer-readable recording medium may also be distributed over a networked computer system and stored and executed in computer readable code in a distributed manner.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Therefore, the scope of the present invention should not be limited to the above-described embodiments, but should be construed to include various embodiments within the scope of the claims.

Claims (20)

A base station for receiving a signal through a multipath channel using a plurality of antennas in a communication system,
Chip level reception beams are formed for the plurality of pre-lake synthesized signals by multiplying the plurality of pre-lake combined pre-lake synthesized signals received through the plurality of antennas by a weight vector corresponding to each of the plurality of antennas. A beam forming unit for performing a function for each user; And
And a despreader for demodulating and demodulating a plurality of user signals by matching and filtering the plurality of pre-lake synthesized signals on which the reception beamforming has been performed. The method of claim 1,
A first demultiplexer configured to extract a reference signal portion from the plurality of pre-lake synthesized signals;
A reference signal generator for generating a reference signal synchronized with a received signal of an L-1 th path among the plurality of pre-lake synthesized signals; And
A weight vector generator configured to generate the weight vector using the extracted reference signal portion and the reference signal generated by the reference signal generator, and provide the generated weight vector to the beam forming unit; A base station characterized in that. The method of claim 1,
A second demultiplexer for extracting a reference signal portion from a signal on which reception beamforming is performed by the beam former; And
A channel estimator estimating a channel for each user by using the reference signal portion extracted by the second demultiplexer and the reference signal generated by the reference signal generator; Further comprising:
And a portion of the user data output from the despreader is corrected to a channel estimate value based on the channel estimate. The method of claim 3,
The second demultiplexer may separate a user data portion from a signal on which a chip level reception beamforming is performed by the beamformer and output the user data portion to the despreader, and the despreader despreads the user data portion. Base station. A terminal for receiving a signal through a multipath channel using a plurality of antennas in a communication system,
Chip level reception beams are formed for the plurality of pre-lake synthesized signals by multiplying the plurality of pre-lake combined pre-lake synthesized signals received through the plurality of antennas by a weight vector corresponding to each of the plurality of antennas. Beam forming unit for performing; And
And a despreader which demodulates and demodulates a user signal of the terminal by matching-filtering the output signal by performing the reception beamforming. The method of claim 5,
A first demultiplexer configured to extract a reference signal portion from the plurality of pre-lake synthesized signals;
A reference signal generator for generating a reference signal synchronized with a received signal of an L-1 th path among the plurality of pre-lake synthesized signals; And
A weight vector generator configured to generate the weight vector using the extracted reference signal portion and the reference signal generated by the reference signal generator, and provide the generated weight vector to the beam forming unit; Terminal, characterized in that. The method of claim 5,
And a second demultiplexer for separating a user data portion from the signal in which the chip level reception beamforming is performed by the beamformer and outputting the user data portion to the despreader. The method of claim 7, wherein
Generated by the reference signal portion and the reference signal generator extracted by the second demultiplexer as the second demultiplexer extracts a reference signal portion from the signal on which the reception beamforming is performed by the beam former. A channel estimator for estimating a channel using the received reference signal; Further comprising:
And a portion of the user data output from the despreader is corrected by a channel estimation value based on the channel estimation. A base station for receiving a signal through a multipath channel using a plurality of antennas,
A despreader which demodulates a plurality of user signals by matched filtering the plurality of pre-lake combined pre-lake synthesized signals received through the plurality of antennas; And
A beam forming unit configured to multiply the weight vector corresponding to each of the plurality of antennas by the plurality of user signals to form a reception level at the symbol level for the plurality of user signals for each user; Base station comprising a. 10. The method of claim 9,
A demultiplexer configured to extract a reference signal portion and a user data portion from the plurality of pre-lake synthesized signals received through the multipath channel;
A reference signal generator for generating a reference signal synchronized with a received signal of an L-1 th path among the plurality of pre-lake synthesized signals; And
The weight vector generator generates the weight vector using the reference signal portion extracted by the demultiplexer and the reference signal generated by the reference signal generator, and provides the generated weight vector to the beam forming unit. And a base station further comprising. 10. The method of claim 9,
A channel for extracting a reference signal portion from the signal on which the reception beamforming is performed by the beam forming unit, and estimating a channel for each user by using the extracted reference signal portion and the reference signal generated by the reference signal generator A base station further comprising an estimator. A terminal for receiving a signal through a multipath channel using a plurality of antennas,
A despreader for demodulating and demodulating a user signal for the terminal by matching-filtering the plurality of pre-lake combined pre-lake synthesized signals received through the plurality of antennas; And
A beam forming unit configured to multiply a weight vector corresponding to each of the plurality of antennas by the user signal to perform symbol beam reception on the user signal; . The method of claim 12,
A demultiplexer configured to extract a reference signal portion and a user data portion from the plurality of pre-lake synthesized signals received through the multipath channel;
A reference signal generator for generating a reference signal synchronized with a received signal of an L-1 th path among the plurality of pre-lake synthesized signals; And
The weight vector generator generates the weight vector using the reference signal portion extracted by the demultiplexer and the reference signal generated by the reference signal generator, and provides the generated weight vector to the beam forming unit. Terminal further comprising. The method of claim 12,
A channel estimating unit extracts a reference signal portion from the signal on which the reception beamforming is performed by the beam forming unit, and estimates a channel using the extracted reference signal portion and the reference signal generated by the reference signal generator. Including a terminal. A method for receiving a signal transmitted through a multipath channel using a plurality of antennas in a base station,
Chip level reception beams are formed for the plurality of pre-lake synthesized signals by multiplying the plurality of pre-lake combined pre-lake synthesized signals received through the plurality of antennas by a weight vector corresponding to each of the plurality of antennas. Performing for each user; And
And demodulating and demodulating a plurality of user signals by matching-filtering the plurality of pre-lake synthesized signals on which the reception beamforming has been performed. 16. The method of claim 15,
Extracting a reference signal portion from the signal on which the reception beamforming is performed;
Estimating a channel using the extracted reference signal portion and a reference signal generated by a reference signal generator for generating a reference signal; And
And correcting a portion of the user data output through the demodulation using a channel estimate value obtained by the channel estimation. A method for receiving a signal transmitted through a multipath channel using a plurality of antennas in a base station,
Demodulating and filtering the plurality of user signals by matched filtering the plurality of pre-lake combined pre-lake composite signals received through the plurality of antennas; And
Multiplying the plurality of user signals by a weight vector corresponding to each of the plurality of antennas to perform reception beamforming at the symbol level for the plurality of user signals for each user; Receiving method comprising a. The method of claim 17,
Extracting a reference signal portion from the signal on which the reception beamforming is performed, and estimating a channel for each user using the extracted reference signal portion and the reference signal generated by the reference signal generator; And
And correcting the signal on which the reception beamforming is performed for each user by using the channel estimation value by the channel estimation. A base station for transmitting a signal using a plurality of antennas in a communication system,
A spreading unit configured to spread-modulate a user signal by using a continuous orthogonal spreading code having orthogonality continuously for a predetermined time interval for each user to generate a spreading signal;
A pre-lake synthesizer for pre-lake combining the spread signal to generate a pre-lake synthesized signal; And
A beam forming unit configured to multiply the pre-lake synthesized signal by a weight vector corresponding to each of the plurality of antennas to perform chip level transmission beamforming; Base station comprising a. 20. The method of claim 19,
Further comprising a weight vector switching unit for providing a weight vector applied in the beam forming unit,
The weight vector is determined by a terminal receiving a signal transmitted from the base station and obtained from the terminal,
And the spreader, the pre-lake synthesizer, and the beamformer are formed by the total number of users present in the communication system.

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