KR20050020133A - Transmitting/receiving apparatus for closed loop space time block code system having multiple input multiple output antennas and method thereof, and transmitting power allocation method thereof - Google Patents

Abstract

PURPOSE: A transceiving device of a closed loop space time block code system having multiple transceiving antennas and a method thereof, and a transmit power assigning method in the system are provided to determine transmit antenna information on a channel having the best transmission state by comparing parameters, and to feed back the determined information to a transmission device, thereby magnifying a receiving SNR(Signal to Noise Ratio) while guaranteeing an improved BER(Bit Error Rate). CONSTITUTION: A transmitter(100) comprises as follows. An information source(110) supplies symbols to a receiver(200). A space time block code unit(120) maps the symbols with space time block codes, generates coded symbols, and outputs the coded symbols to paths as many as transmit antennas(140). A weight supplier(130) determines a weight according to information fed back through a feedback path from the receiver(200), supplies weights corresponding to each signal outputted from the space time block code unit(120), and assigns a transmit power.

Description

Transmission and reception apparatus of closed loop space-time block coding system having multiple transmit / receive antennas and method for allocating transmit power in the system AND TRANSMITTING POWER ALLOCATION METHOD THEREOF}

The present invention relates to a multiple input multiple output (MIMO) system using multiple antennas at a transmitting end and multiple antennas at a receiving end. More specifically, the present invention proposes a MIMO system. A transmission / reception apparatus for a closed loop space-time block coding system using a space time block code, which is a coding method, and a method thereof, and a transmission power allocation method in the system.

The space-time block code proposed for the MIMO wireless communication system provides the maximum diversity gain to the system through a simple linear combining scheme at the receiving end. In the conventional MIMO space-time block coding system using such a space-time block code, the same amount of weight is applied to multiple transmit antennas by collectively weighting the same amount of weight even though the channel conditions corresponding to each antenna of the transmitter are different. Has a problem of allocating transmit power. That is, the limited transmission power is distributed even to the antenna having a poor channel state, thereby depriving the antenna of a good channel state of the opportunity to increase the transmission power distribution efficiency. This may be desirable in terms of complexity of the transmission and reception system, but not in terms of efficiency of transmission power, which is most important in a wireless communication system.

Accordingly, the technical problem of the present invention is to solve the above problems, and multiple transmission / reception for allocating transmission power of a transmitter in a direction of optimizing bit error rate (BER) performance in a receiver is performed. An apparatus for transmitting and receiving a closed loop space-time block coding system having an antenna, and a method of allocating a transmission power in the system.

Transmission apparatus of a MIMO system according to an aspect of the present invention for achieving the above object,

In a MIMO system, a transmission device for transmitting a signal through a multiple transmission channel, wherein the reception device includes a multiple reception antenna, wherein the transmission device includes a multiple transmission antenna.

A space-time block encoder for generating signals that can be transmitted through the multiple transmit antennas by performing space-time block encoding on a signal to be transmitted to the receiving device; And a weight supply unit configured to apply a weight so that maximum power is allocated to a signal supplied to a transmission antenna corresponding to a channel having a best transmission channel state among the signals output from the space-time block encoder, and output the result to the multiplex transmission antenna. The multi-transmitting antenna may receive the power allocated signal from the weight supply unit and transmit the signal to the receiving device.

The weight supply unit may include: a weight determiner configured to determine respective weights to be applied to signals output from the space-time block encoder based on the state of the transport channel; And a multiplier for multiplying each weight determined by the weight determiner to correspond to each signal output from the space-time block encoder and outputting the multiplied output to the corresponding transmit antennas.

In addition, the transmission antenna information corresponding to the channel having the best transmission channel state is determined by mutual comparison of the parameters of the transmission channel estimated by the receiving device, and from the receiving device to the transmitting device through a specific feedback path. It is preferable to be fed back.

In addition, it is preferable that the transmitting apparatus compares each other with transmission channel parameters, which are estimated by the receiving apparatus and transmitted through a specific feedback path, for transmission antenna information corresponding to a channel having the best transmission channel state.

In addition, the sum of the weights is 1, and the weight supply unit sets the weight applied to the signal supplied to the transmission antenna corresponding to the channel having the best transmission channel state to 1, and the weight applied to the remaining signals is 0. The maximum power is preferably allocated to a signal supplied to a transmission antenna corresponding to a channel having the best transmission channel state.

Further, according to the change of the space-time block code unit of the transmission channel state, it is preferable that the transmission antenna corresponding to the channel having the best transmission channel state is determined in the space-time block code unit.

Receiving apparatus of the MIMO system according to another aspect of the present invention,

In a MIMO system, a receiving device for receiving a signal transmitted from a transmitting device over a multiple transmission channel, wherein the transmitting device includes a multiple transmitting antenna, wherein the receiving device includes a multiple receiving antenna.

A channel for receiving the signals of the multipath received through the multiple reception antennas, estimating each transmission channel parameter representing the state of the multiple transmission channels, and returning the estimated respective transmission channel parameters to the transmitting device through a specific feedback path Estimator; A combiner for linearly combining and outputting each signal output from the channel estimator; And a maximum likelihood detector that detects a signal transmitted from the transmitter by evaluating a value combined and output by the combiner in a maximum likelihood scheme.

Receiving apparatus of a MIMO system according to another aspect of the present invention,

In a MIMO system, a receiving device for receiving a signal transmitted from a transmitting device over a multiple transmission channel, wherein the transmitting device includes a multiple transmitting antenna, wherein the receiving device includes a multiple receiving antenna.

Receiving the signals of the multipath received through the multiple reception antennas, estimating each transmission channel parameter indicative of the state of the multiple transmission channels, and comparing the estimated respective transmission channel parameters with each other to determine among the multiple transmission antennas of the transmitting apparatus. A channel estimating and channel state comparing unit for determining a transmitting antenna corresponding to a transmission channel having a best state and returning it to the transmitting apparatus through a specific feedback path; A combiner for linearly combining and outputting each signal output from the channel estimation and channel state comparator; And a maximum likelihood detector that detects a signal transmitted from the transmitter by evaluating the combined value output from the combiner in a maximum likelihood manner.

Here, the channel estimating and channel state comparing unit includes: a channel estimator estimating a transmission channel parameter representing each state of the multiple transmission channels using signals of the multipath received through the multiple reception antennas; And a channel state comparator comparing the respective transmission channel parameters estimated by the channel estimator to determine a transmission antenna corresponding to a transmission channel having the best state, and returning the signal to the transmission apparatus through the specific feedback path.

In addition, the channel estimation and channel state comparison unit preferably compares the estimated magnitudes of the respective transmission channel parameters to determine a transmission antenna having the best transmission channel state.

In addition, it is preferable that the transport channel parameter is determined in the space time block code unit according to the change in the space time block code unit of the transport channel state.

In addition, according to the change of the space-time block code unit of the transmission channel state, it is preferable that the transmission antenna corresponding to the channel having the best transmission channel state is determined in the space-time block code unit.

Signal transmission method in a MIMO system according to another aspect of the present invention,

A method of transmitting a signal in a MIMO system comprising a transmitting device for transmitting a signal over a multiple transmission channel, wherein the receiving device includes a multiple receiving antenna, wherein the transmitting device comprises a multiple transmitting antenna. ,

a) space-time block encoding the signal to be transmitted to the receiving device to generate signals that can be transmitted through the multiple transmit antennas; b) applying a weight such that a maximum power is allocated to a signal supplied to a transmission antenna corresponding to a channel having a best transmission channel state among the generated signals; And c) transmitting the weighted signal to the receiving device through the multiple transmit antenna.

Signal reception method in a MIMO system according to another aspect of the present invention,

A receiving device for receiving a signal transmitted from a transmitting device over a multiple transmission channel, wherein the transmitting device includes a multiple transmitting antenna, wherein the receiving device comprises a multiple receiving antenna. As a method,

a) receiving a multipath signal received through the multiple receive antennas and estimating each transport channel parameter indicative of a state of the multiplexed transmission channel; b) returning the estimated respective transmission channel parameters to the transmitting device through a specific feedback path; c) linearly combining and outputting the received signals; And d) evaluating the combined value in a maximum likelihood manner to detect a signal transmitted from the transmitting device.

Signal reception method in a MIMO system according to another aspect of the present invention,

A receiving device for receiving a signal transmitted from a transmitting device over a multiple transmission channel, wherein the transmitting device includes a multiple transmitting antenna, wherein the receiving device comprises a multiple receiving antenna. As a method,

a) receiving a multipath signal received through the multiple receive antennas and estimating each transport channel parameter indicative of a state of the multiplexed transmission channel; b) comparing the estimated respective transmission channel parameters with each other to determine a transmission antenna corresponding to a transmission channel having the best state among the multiple transmission antennas of the transmission apparatus; c) returning the determined transmit antenna information to the transmitting device through a specific feedback path; d) linearly combining and outputting the received signals; And e) evaluating the combined value in a maximum likelihood manner to detect a signal transmitted from the transmitting device.

Transmission power allocation method in a MIMO system according to another aspect of the present invention,

In a MIMO system comprising a transmitting device, wherein the transmitting device comprises a multiple transmitting antenna and a receiving device receiving a signal transmitted from the transmitting device over a multiple transmission channel, wherein the receiving device comprises a multiple receiving antenna. A method of allocating transmit power,

a) receiving, by the receiving apparatus, a multipath signal received through the multiple receiving antennas and estimating each transmission channel parameter representing a state of the multiple transmission channels; b) the receiving apparatus compares each of the estimated transmission channel parameters with each other to determine a transmitting antenna corresponding to a transmission channel having the best state among the multiple transmitting antennas of the transmitting apparatus, and transmits to the transmitting apparatus through a specific feedback path. Feedback; c) applying a weight such that the maximum power is allocated to a signal supplied to a transmission antenna identified in the information fed back from the receiving apparatus in step b) of the signals to be transmitted to the receiving apparatus; And d) the transmitting device transmitting the weighted signal to the receiving device through the multiple transmit antenna.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention. Like parts are designated by like reference numerals throughout the specification.

First, a MIMO closed loop space-time block coding system according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram of a MIMO closed loop space-time block coding system according to an embodiment of the present invention.

As shown in FIG. 1, a MIMO closed loop space-time block coding system according to an embodiment of the present invention includes a transmitter 100 and a receiver 200.

The transmitter 100 includes an information source 110, a space-time block encoder 120, a weight supply 130, and a transmit antenna 140, and the receiver 200 includes a receive antenna 210, a channel estimation and a channel state comparator ( 220, a combiner 230, and a maximum likelihood detector 240.

The information source 110 of the transmitter 100 is a symbol to be transmitted to the receiver 200. Is provided, the space-time block encoder 120 is a symbol provided from the information source 110 The symbols encoded by the space-time block codes are mapped to the space-time block codes, and output as many paths as the number of transmit antennas 140 for transmission diversity.

The weight supplier 130 determines the weight according to the information fed back through the feedback path at the receiver 200, and the weight corresponding to each signal output from the space-time block encoder 120 ( ) To allocate transmit power. In the embodiment of the present invention, the weight supplier 130 sets the weight corresponding to the signal input to the best transmitting antenna with the channel state fed back from the receiver 200 to 1, and corresponds to the signal input to the remaining transmitting antenna. All weights are set to zero. Here, setting the weight to 1 means that all of the transmit powers are allocated to the signal having the weight set to 1, and that the transmit power is not allocated to the signal having the remaining weight set to 0.

Transmit antenna 140 has multiple ( ) And transmits a signal output from the space-time block encoder 120 and weighted by the weight supply unit 130 to the receiver 200. In the exemplary embodiment of the present invention, only the transmission antenna 140 that receives a signal having a weight set to 1 among the signals output from the space-time block encoder 120 may transmit the corresponding signal to the receiver 200 at the maximum transmission power. In this case, since the information fed back from the receiver 200 may change according to the change in the channel state, the transmission antenna 140 that transmits the signal at the maximum transmit power may also change according to the change in the channel state. . Since the channel state changes every block unit time of the space-time block code, the transmission antenna 140 to transmit a signal having a weight set to 1 may also change every block unit time of the space-time block code.

On the other hand, the receiving antenna 210 of the receiver 200 is a number ( ) Is provided with a receiving antenna, and the transmitter 100 receives a signal transmitted through a channel of a multipath.

The channel estimation and channel state comparator 220 receives the signals of the multipath received through the reception antenna 210, estimates the parameters of each channel, and compares the state of the channels determined by the estimated channel parameters with each other. The transmit antenna information having the best channel state is determined and fed back to the transmitter 100 through the feedback path.

The combiner 230 linearly combines each signal output through the channel estimate and channel state comparator 220 to produce a combined estimate with a higher reliability of the received signal.

The maximum likelihood detector 240 detects a symbol transmitted from the transmitter 100 by evaluating the combined value output from the combiner 230 in a maximum likelihood scheme.

2 is a detailed block diagram of the channel estimation and channel state comparator 220 shown in FIG.

As shown in FIG. 2, the channel estimate and channel state comparator 220 includes a channel estimator 222 and a channel state comparator 224.

The channel estimator 222 is received via the receive antenna 210 Using the two signals, a parameter representing each state of a transmission channel formed between the transmitting antenna 140 of the transmitter 100 and the receiving antenna 210 of the receiver 200 is estimated. Since such channel estimation is performed through a conventional channel estimation method, a detailed description thereof will be omitted.

The channel state comparator 224 compares the state of each channel with each other by using the parameters of each channel estimated by the channel estimator 222 to determine the transmission channel having the best channel state, that is, the transmit antenna 140, and the determined channel. Information is provided to the weight supplier 130 of the transmitter 100 through the feedback path. Here, the state of the transport channel is determined by comparing the magnitude of the estimated channel parameter for each channel. That is, the channel estimated to have the largest channel parameter becomes the best channel, and the transmission antenna 140 transmitting the signal through this channel is determined as final information, so that the weight supply 130 of the transmitter 100 is determined. Is fed back.

3 is a detailed block diagram of the weight supply 130 shown in FIG.

As shown in FIG. 3, the weight supplier 130 includes a weight determiner 132 and a plurality ( ) Multipliers (134-1, 134-2,…, 134- ).

The weight determiner 132 may determine each weight corresponding to each signal output from the space-time block encoder 120 based on the channel estimation of the receiver 200 and the channel state information returned from the channel state comparator 220. Is determined. In an embodiment of the present invention, the weight determiner 132 is a channel estimation and channel state comparator 220, more specifically, a channel state comparator 224 of the receiver 200 to ensure optimal BER at the receiver 200. The weight corresponding to the signal to be input to the transmitting antenna 140 determined from the feedback channel state information is determined as 1, and all weights corresponding to other signals are determined as 0.

Multiple multipliers (134-1, 134-2, ..., 134- ) Multiplies each weight determined by the weight determiner 132 so as to correspond to each signal output from the space-time block encoder 120, and outputs the weights to the corresponding transmit antennas 140, respectively.

As such, only one weight is determined by the weight determiner 132 to be 1, and the weight is multiplied by only one signal output from the space-time block encoder 120 so that the maximum power is allocated so that the channel state is the best. The signal to noise ratio (SNR, hereinafter referred to as 'receive SNR') at the receiver 200 is maximized by being transmitted through the transmit antenna 140, which causes the receiver 200 to be maximized. BER in can be optimized.

Hereinafter, a power allocation method in a MIMO closed loop space-time block coding system according to an embodiment of the present invention will be described in detail.

First, a symbol provided from the information source 110 of the transmitter 100 Is input to the space-time block encoder 120 to generate a space-time block code. In the embodiment of the present invention, the symbol provided from the information source 110 is limited to a symbol having the form of a real constellation.

As such, the space-time block code signals generated by the space-time block coder 120 are allocated power by the weight supply unit 130 before the signal is propagated through the transmission antenna 140. Each weight Is multiplied by each signal output from the space-time block encoder 120 by a multiplier. here Denotes the weight of the t th transmit antenna. At this time, every signal transmission time interval Powers transmitted by the two transmit antennas 140 must always be 1 so that each weight Must satisfy the following Equation 1.

As such, the signals allocated to the power through the weight supplier 130 are transmitted to the receiver 200 through the transmission antenna 140.

Meanwhile, the signals transmitted from the transmitter 100 experience a fading channel of different paths. The characteristics of these wireless fading channels are complex parameters Denoted as a channel state between the i th transmit antenna 140 and the j th receive antenna 210. Determination of good and bad of channel condition This is determined by comparing the size information of. In the embodiment of the present invention, it is assumed that the receiver 200 completely estimates a parameter of a channel and detects received signals coherently. The signals that experienced each fading channel were Is received by the receiving antenna 210, and the combiner 230 combines the received signals and outputs an output signal such as the following [Equation 2] or [Equation 3] by the principle of maximum likelihood detection. Outputs At this time, the output signal of the combiner 230 Is a square space (generates a square space-time block code when the number of transmitting antennas is 2, 4, 8, etc.) or a bissquare form (3, 5, 6, 7, etc.) Have a different structure, depending on whether they generate bis-square space-time block codes. Coupler 230 output signal when square space-time block code Is expressed by [Equation 2].

here, Is a signal received by the j-th receiving antenna 210 in the t-th time interval, In the t th column of the received space-time block The position of the row containing the, Is in the t th column of the space-time block Is the sign of.

On the other hand, the combiner 230 output signal when the non-square space-time block code Is represented by [Equation 3].

here, In space-time block code Means a set of columns containing.

Received signal in [Equation 2] and [Equation 3] Substituting Equation 2 may be represented by Equation 4 below, and Equation 3 may be expressed by Equation 5 below. Finally, output signal of combiner 230 for square space-time block code Is the same as [Equation 4],

Output signal of combiner 230 for bisqueous space-time block code Is the same as [Equation 5].

As such, the signal is coupled and output by the combiner 230 Is input to the maximum likelihood detector 240 for the detection of a symbol, and the maximum likelihood detector 240 is input to the input signal. To evaluate the final detected signal Create

In the equations described above, the weight supplier 130 applies the weight to the transmit antenna 230. Was not specified as a specific value. Where each weight Specifying a specific value is a power allocation scheme for each channel. Therefore, this weight It will be described how to obtain the optimal BER in the receiver 200 only by specifying.

To ensure optimal BER for the receiver 200, the reception SNR should be maximized. Therefore, the power allocation method in the MIMO closed loop space-time block coding system according to an embodiment of the present invention allocates the transmission power allocated to each transmission antenna 140 in the transmitter 100 so that the reception SNR of the receiver 200 is maximized. will be.

First, the received SNR from Equation 4 and Equation 5 may be derived as shown in Equation 6 below.

In this case, the received SNR is expressed by Equation 6 for both the square and the non-square square space block code. here Is the transmission SNR of the symbol. Equation 6 is expressed again by Equation 7 below.

here Denotes the order of the transmit antenna 140 having the t-th good channel state. For example, if the third transmit antenna of the multiple transmit antennas 140 has the first good channel condition Becomes three. If the antenna with the second best channel condition is the fourth of the multiple transmit antennas 140, Becomes four. On the other hand, the magnitude relationship of the channel state can be expressed as Equation 8 below.

On the other hand, since the total power transmitted by the multiple transmit antennas 140 should be 1, the weight should satisfy the relational expression of Equation 1 above. [Equation 1] To an expression using Becomes In other words The relation for is expressed by Equation 9 below.

Substituting this Equation 9 into Equation 7, the received SNR at the receiver 200 is represented by Equation 10 below.

According to Equation 10, the received SNR is a weight for the transmit antenna 140. Is a function dependent on. Where the weight for the transmit antenna 140 Receive SNR is reduced even if any value except 0 is weighted. Because each weight in [Equation 10] by [Equation 8] This is because the coefficients of are all negative. Therefore, referring to Equation 10, in order to maximize the reception SNR, the weight for the transmitting antenna 140 is increased. Must be set to all zeros. As a result, Equation 10 may be expressed again by Equation 11 below.

here Is A parameter representing a channel state between the first transmit antenna 140 and the jth receive antenna 210. Referring to Equation 11, the condition that the received SNR is maximum is the best channel condition. The weight 0 is assigned to all the transmit antennas 140 except for the first transmit antenna 140, and the channel state is the best. The weight 1 is allocated to the first transmit antenna 140. That is, the optimal power allocation method for the MIMO closed loop space-time block coding system selects one transmission antenna 140 having the best channel state among the multiple transmission antennas 140 and allocates all transmission powers to the antenna. In other words, no power is allocated to the remaining transmit antennas 140.

In this case, since the channel state changes every block unit time of the space-time block code, the channel estimation and channel state comparator 220 of the receiver 200, in particular, the receiver 200 estimates the state of the channel according to every channel change. The respective channel states are compared to determine which transmission antenna 140 has the best channel state, and the determined information is fed back through the feedback path between the receiver 200 and the transmitter 100.

The proposed power allocation method as described above has a strong characteristic of the effect of time delay due to feedback since the operation for obtaining feedback information in the receiver 200 is small and the number of bits of feedback information is small.

4 is a diagram illustrating the performance when the power allocation method according to an embodiment of the present invention is applied to a MIMO closed loop space-time block encoding system having four transmit antennas and one and two receive antennas, and a conventional open-loop space-time block encoding system. It is a figure which shows the simulation result comparing performance.

Referring to FIG. 4, in a system having four transmit antennas and one receive antenna, In order to achieve BER, the conventional open loop space-time block coding system requires a transmission SNR of about 10 dB. However, the MIMO closed-loop space-time block coding system according to the embodiment of the present invention is compared with the conventionally required transmission power. It is shown that it needs a small about 7.5dB.

Although the preferred embodiment of the present invention has been described in detail above, the present invention is not limited thereto, and various other changes and modifications are possible.

For example, in the above, the receiver 200 estimates a channel parameter from the received signals, compares the estimated channel parameters with each other, determines a transmission antenna 140 having the best channel state, and transmits the transmitter 100 through a feedback path. ), And the transmitter 100 only sets the weight to 1 for a signal supplied to the corresponding transmission antenna 140 according to the information of the transmission antenna 140 returned from the receiver 200, but the present invention has been described. The technical scope of the present invention is not limited thereto, and the receiver 200 only estimates a channel parameter from the received signals, and if the estimated channel parameter is fed back to the transmitter 100 through a feedback path, the transmitter 100 receives the receiver. By comparing the channel parameter information fed back from the (200) with each other to determine the transmit antenna 140 having the best channel state, and only to the signal supplied to the determined transmit antenna 140 The weight may be set to one. As such, determining the transmit antenna 140 having the best channel state by comparing the channel parameters with the transmitter 100 may be performed by those skilled in the art when referring to the structure and function of the channel state comparator 224 of the receiver 200. Will be very easily understood.

According to the present invention, the reception SNR of the receiver is maximized in a MIMO closed loop space-time block coding system environment, thereby ensuring an improved BER compared to the prior art.

1 is a block diagram of a MIMO closed loop space-time block coding system according to an embodiment of the present invention.

FIG. 2 is a detailed block diagram of the channel estimation and channel state comparator shown in FIG. 1.

3 is a detailed block diagram of the weight feeder shown in FIG.

4 is a diagram illustrating the performance when the power allocation method according to an embodiment of the present invention is applied to a MIMO closed loop space-time block encoding system having four transmit antennas and one and two receive antennas, and a conventional open-loop space-time block encoding system. It is a figure which shows the simulation result comparing performance.

Claims (18)

In a Multiple Input Multiple Output (MIMO) system, a transmission device for transmitting a signal through a multiple transmission channel, wherein the reception device includes multiple reception antennas, where the transmission device includes multiple transmission antennas. In terms of A space-time block encoder for generating signals that can be transmitted through the multiple transmit antennas by performing space-time block encoding on a signal to be transmitted to the receiving device; And A weight supply unit for applying a weight to allocate a maximum power to a signal supplied to a transmission antenna corresponding to a channel having the best transmission channel state among the signals output from the space-time block encoder and outputting the result to the multiplex transmission antenna. Including; The multi-transmission antenna receives a power allocated signal from the weight supply unit and transmits the signal to the receiving device Transmission apparatus of a multiple input multiple output system, characterized in that. The method of claim 1, The weight supply unit, A weight determiner for determining respective weights to be applied to signals output from the space-time block encoder based on the state of the transport channel; And A multiplier for multiplying each weight determined by the weight determiner to correspond to each signal output from the space-time block encoder and outputting the multiplied output to the corresponding transmit antennas Transmission apparatus of a multiple input multiple output system comprising a. The method according to claim 1 or 2, The transmission antenna information corresponding to the channel having the best transmission channel state is determined by mutual comparison of the parameters of the transmission channel estimated by the receiving apparatus, and is fed back from the receiving apparatus to the transmitting apparatus through a specific feedback path. Transmission apparatus of a multiple input multiple output system, characterized in that. The method according to claim 1 or 2, Transmitting antenna information corresponding to the channel having the best transmission channel state is estimated by the receiving apparatus, and the transmitting apparatus compares each other to determine transmission channel parameters transmitted through a specific feedback path. Transmission device. The method according to claim 1 or 2, The sum of the weights is 1, The weight supply unit sets a weight applied to a signal supplied to a transmission antenna corresponding to a channel having the best transmission channel state to 1 and a weight applied to the remaining signals to 0 so that the channel having the best transmission channel state is set. The maximum power is allocated to the signal supplied to the transmitting antenna corresponding to Transmission apparatus of a multiple input multiple output system, characterized in that. The method according to claim 1 or 2, And a transmission antenna corresponding to a channel having the best transmission channel state is determined in the space time block code unit according to the change of the space time block code unit of the transmission channel state. In a multiple input multiple output system, a receiving device for receiving a signal transmitted from a transmitting device over a multiple transmission channel, wherein the transmitting device includes a multiple transmitting antenna, wherein the receiving device comprises a multiple receiving antenna. A channel for receiving the signals of the multipath received through the multiple reception antennas, estimating each transmission channel parameter representing the state of the multiple transmission channels, and returning the estimated respective transmission channel parameters to the transmitting device through a specific feedback path Estimator; A combiner for linearly combining and outputting each signal output from the channel estimator; And A maximum likelihood detector which detects a signal transmitted from the transmitter by evaluating the combined value outputted from the combiner in a maximum likelihood scheme Receiving device of a multiple input multiple output system comprising a. In a multiple input multiple output system, a receiving device for receiving a signal transmitted from a transmitting device over a multiple transmission channel, wherein the transmitting device includes a multiple transmitting antenna, wherein the receiving device comprises a multiple receiving antenna. Receiving the signals of the multipath received through the multiple reception antennas, estimating each transmission channel parameter indicative of the state of the multiple transmission channels, and comparing the estimated respective transmission channel parameters with each other to determine among the multiple transmission antennas of the transmitting apparatus. A channel estimating and channel state comparing unit for determining a transmitting antenna corresponding to a transmission channel having a best state and returning it to the transmitting apparatus through a specific feedback path; A combiner for linearly combining and outputting each signal output from the channel estimation and channel state comparator; And A maximum likelihood detector which detects a signal transmitted from the transmitter by evaluating the combined value outputted from the combiner in a maximum likelihood manner Receiving device of a multiple input multiple output system comprising a. The method of claim 8, The channel estimation and channel state comparison unit, A channel estimator estimating a transmission channel parameter representing each state of the multiple transmission channel using signals of the multipath received through the multiple reception antennas; And A channel state comparator that compares each transmission channel parameter estimated by the channel estimator to determine a transmission antenna corresponding to a transmission channel having the best state, and returns the feedback to the transmitting apparatus through the specific feedback path. Receiving device of a multiple input multiple output system comprising a. The method according to claim 8 or 9, And the channel estimation and channel state comparison unit compares the estimated magnitudes of the respective transmission channel parameters to determine a transmission antenna having a best transmission channel state. The method of claim 7, wherein And the transmission channel parameter is determined in the space time block code unit according to the change of the space time block code unit of the transport channel state. The method according to claim 8 or 9, And a transmission antenna corresponding to a channel having the best transmission channel state is determined in the space time block code unit according to the change of the space time block code unit of the transmission channel state. Transmitting a signal in a multiple input multiple output system comprising a transmitting device for transmitting a signal over a multiple transmission channel, wherein the receiving device comprises a multiple receiving antenna, wherein the transmitting device comprises a multiple transmitting antenna. In the way, a) space-time block encoding the signal to be transmitted to the receiving device to generate signals that can be transmitted through the multiple transmit antennas; b) applying a weight such that a maximum power is allocated to a signal supplied to a transmission antenna corresponding to a channel having a best transmission channel state among the generated signals; And c) transmitting the weighted signal to the receiving device through the multiple transmit antenna Signal transmission method in a multiple input multiple output system comprising a. The method of claim 13, Transmitting antenna information corresponding to the channel having the best transmission channel state is determined by mutual comparison of parameters of the transmission channel estimated by the receiving apparatus, and is fed back from the receiving apparatus through a specific feedback path. Signal transmission method in multiple input multiple output system. The method of claim 13, Transmitting antenna information corresponding to the channel having the best transmission channel state is estimated by the receiving apparatus, and the transmitting apparatus compares each other to determine transmission channel parameters transmitted through a specific feedback path. Signal transmission method in Signal in a multiple input multiple output system comprising a receiving device for receiving a signal transmitted from a transmitting device over a multiple transmission channel, wherein the transmitting device comprises a multiple transmitting antenna, wherein the receiving device comprises a multiple receiving antenna. In the method for receiving, a) receiving a multipath signal received through the multiple receive antennas and estimating each transport channel parameter indicative of a state of the multiplexed transmission channel; b) returning the estimated respective transmission channel parameters to the transmitting device through a specific feedback path; c) linearly combining and outputting the received signals; And d) evaluating the combined value in a maximum likelihood manner to detect a signal transmitted from the transmitting device Signal receiving method in a multiple input multiple output system comprising a. Signal in a multiple input multiple output system comprising a receiving device for receiving a signal transmitted from a transmitting device over a multiple transmission channel, wherein the transmitting device comprises a multiple transmitting antenna, wherein the receiving device comprises a multiple receiving antenna. In the method for receiving, a) receiving a multipath signal received through the multiple receive antennas and estimating each transport channel parameter indicative of a state of the multiplexed transmission channel; b) comparing the estimated respective transmission channel parameters with each other to determine a transmission antenna corresponding to a transmission channel having the best state among the multiple transmission antennas of the transmission apparatus; c) returning the determined transmit antenna information to the transmitting device through a specific feedback path; d) linearly combining and outputting the received signals; And e) evaluating the combined value in a maximum likelihood manner to detect a signal transmitted from the transmitting device Signal receiving method in a multiple input multiple output system comprising a. Multi-input multiplexing comprising a transmitting device, wherein the transmitting device comprises a multiple transmitting antenna and a receiving device receiving a signal transmitted from the transmitting device over a multiple transmission channel, wherein the receiving device comprises a multiple receiving antenna. A method of allocating transmit power in an output system, a) receiving, by the receiving apparatus, a multipath signal received through the multiple receiving antennas and estimating each transmission channel parameter representing a state of the multiple transmission channels; b) the receiving apparatus compares each of the estimated transmission channel parameters with each other to determine a transmitting antenna corresponding to a transmission channel having the best state among the multiple transmitting antennas of the transmitting apparatus, and transmits to the transmitting apparatus through a specific feedback path. Feedback; c) applying a weight such that the maximum power is allocated to a signal supplied to a transmission antenna identified in the information fed back from the receiving apparatus in step b) of the signals to be transmitted to the receiving apparatus; And d) transmitting, by the transmitting device, the weighted signal to the receiving device through the multiple transmit antenna; Transmission power allocation method in a multiple input multiple output system comprising a.