WO2005020466A1 - Transmitting and receiving device and method for closed loop space time block coding system having multiple input multiple output antenna, and transmit power allocation method for the system - Google Patents

Transmitting and receiving device and method for closed loop space time block coding system having multiple input multiple output antenna, and transmit power allocation method for the system Download PDF

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Publication number
WO2005020466A1
WO2005020466A1 PCT/KR2003/002787 KR0302787W WO2005020466A1 WO 2005020466 A1 WO2005020466 A1 WO 2005020466A1 KR 0302787 W KR0302787 W KR 0302787W WO 2005020466 A1 WO2005020466 A1 WO 2005020466A1
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WO
WIPO (PCT)
Prior art keywords
transmit
transmitter
receiver
channel
signals
Prior art date
Application number
PCT/KR2003/002787
Other languages
French (fr)
Inventor
Kunmin Yeo
Seokjoo Shin
Byunghan Ryu
Dujeong Choi
Kiseon Kim
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Electronics And Telecommunications Research Institute
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Application filed by Electronics And Telecommunications Research Institute filed Critical Electronics And Telecommunications Research Institute
Priority to AU2003286970A priority Critical patent/AU2003286970A1/en
Publication of WO2005020466A1 publication Critical patent/WO2005020466A1/en

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/02—Arrangements for detecting or preventing errors in the information received by diversity reception
    • H04L1/06—Arrangements for detecting or preventing errors in the information received by diversity reception using space diversity
    • H04L1/0618—Space-time coding
    • H04L1/0625—Transmitter arrangements
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
    • H04B7/0613—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission
    • H04B7/0615—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal
    • H04B7/0619—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal using feedback from receiving side
    • H04B7/0621—Feedback content
    • H04B7/0626—Channel coefficients, e.g. channel state information [CSI]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/0001—Systems modifying transmission characteristics according to link quality, e.g. power backoff
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W72/00—Local resource management
    • H04W72/04—Wireless resource allocation

Definitions

  • the present invention relates to a MIMO (multiple input multiple output) system for using a multiple antenna at a transmit terminal and a multiple antenna at a receive terminal. More specifically, the present invention relates to a transmitting and receiving device and method of a closed-loop space-time block encoding system that uses space-time block codes developed for a MIMO system.
  • Space-time block codes proposed for the MIMO radio communication system provide the maximum diversity gain to the same system through a simple linear combination method at a receiver. Since the conventional MIMO space-time block encoding system using the time-space block codes allocates the same amount of weights to antennas equally even though the channel states corresponding to the respective antennas are different, the same amount of transmit power is problematically applied to a plurality of transmit antennas. That is, since limited transmit power is provided to antennas with bad channel states, cases where more power is allocated to antennas with good channel states to increase efficiencies of transmit power distribution are not extant, which may be desirable from the viewpoint of complexity of the transmitting and receiving system, but which is not desirable from the viewpoint of efficiencies of transmit power that is the most important factor in the radio communication system.
  • a transmitter of a MIMO system wherein the transmitter transmits signals to a receiver through multiple transmit channels, the transmitter includes multiple transmit antennas, and the receiver includes multiple receive antennas, comprises: a space time block encoder for performing space time block encoding on signals to be transmitted to the receiver, and generating signals to be transmitted through the multiple transmit antennas; and a weight supplier for applying weights so that the maximum power may be allocated to the signal that is supplied to the transmit antenna that corresponds to the channel with the best transmit channel state from among the signals output from the space time block encoder, and outputting it to the multiple transmit antenna, and the multiple transmit antenna receiving the signal to which power is allocated from the weight supplier, and transmitting the signal to the receiver.
  • the weight supplier comprises: a weight determiner for determining respective weights to be applied to the signals which are output from the space time block encoder based on the states of the transmit channel; and a multiplier for multiplying the respective weights determined by the weight determiner by the respective signals output by the space time block encoder, and outputting multiplication results to the corresponding transmit antennas.
  • the transmit antenna information corresponding to the channel with the best transmit channel state is determined by comparing the parameters of the transmit channels estimated by the receiver, and fed back to the transmitter from the receiver through a specific feedback path.
  • the transmit antenna information corresponding to the channel with the best transmit channel state is determined by the transmitter by comparing the transmit channel parameters estimated by the receiver and transmitted through the specific feedback path.
  • the summation of the weights is 1 , and the weight supplier establishes the weight applied to the signal supplied to the transmit antenna corresponding to the channel with the best transmit channel state as 1 , and the weights applied to other signals as 0 so that the maximum power may be allocated to the signal supplied to the transmit antenna corresponding to the channel with the best transmit channel state.
  • the transmit antenna corresponding to the channel with the best transmit channel state is determined as a space time block code unit according to a change of the space time block code unit of the transmit channel state.
  • a receiver of a MIMO system wherein the receiver receives signals from a transmitter through multiple transmit channels, the transmitter includes multiple transmit antennas, and the receiver includes multiple receive antennas, comprises: a channel estimator for receiving multipath signals through the multiple receive antennas, estimating respective transmit channel parameters that show states of the multiple transmit channels, and feeding the respective estimated transmit channel parameters to the transmitter through a specific feedback path; a combiner for linearly combining the respective signals output by the channel estimator; and a maximum likelihood detector for evaluating the values output by the combiner according to the maximum likelihood method, and detecting the signals transmitted from the transmitter.
  • a receiver of a MIMO system wherein the receiver receives signals from a transmitter through multiple transmit channels, the transmitter includes multiple transmit antennas, and the receiver includes multiple receive antennas, comprises: a channel estimator and channel state comparator unit for receiving multipath signals through the multi receive antennas, estimating respective transmit channel parameters that show states of the multi transmit antennas, comparing the respective estimated transmit channel parameters, determining the transmit antenna corresponding to the transmit channel with the best state from among the multiple transmit antennas of the transmitter, and feeding it to the transmitter through a specific feedback path; a combiner for linearly combining the respective signals output by the channel estimator and channel state comparator unit, and outputting results; and a maximum likelihood detector for evaluating the values output by the combiner according to the maximum likelihood method, and detecting the signals transmitted from the transmitter.
  • the channel estimator and channel state comparator unit comprises: a channel estimator for using the multipath signals received through the multiple receive antennas, and estimating transmit channel parameters that show respective states of the multiple transmit channels; and a channel state comparator for respectively comparing the respective transmit channel parameters estimated by the channel estimator, determining the transmit antenna corresponding to the transmit channel with the best state, and feeding it back to the transmitter through the specific feedback path.
  • the channel estimator and channel state comparator unit compares sizes of the estimated transmit channel parameters, and determines the transmit antenna with the best transmit channel state.
  • the transmit channel parameters are determined by a space time block code unit according to changes of the space time block code unit of the transmit channel state.
  • a method for transmitting signals in a MIMO system including a transmitter for transmitting signals to a receiver through multiple transmit channels wherein the transmitter includes multiple transmit antennas and the receiver includes multiple receive antennas, comprises: (a) performing space time block encoding on signals to be transmitted to the receiver, and generating signals to be transmitted through the multiple transmit antenna; (b) applying weights so that the maximum power may be allocated to the signal supplied to the transmit antenna corresponding to the channel with the best transmit channel state from among the generated signals; and (c) transmitting the weight-applied signals to the receiver through the multiple transmit antennas.
  • a method for receiving signals in a MIMO system including a receiver for receiving signals from a transmitter through multiple transmit channels wherein the transmitter includes multiple transmit antennas and the receiver includes multiple receive antennas, comprises: (a) receiving multipath signals through the multi receive antennas, and estimating respective transmit channel parameters that show states of the multiple transmit channels; (b) feeding the respective estimated transmit channel parameters back to the transmitter through a specific feedback path; (c) linearly combining the received signals, and outputting results; and (d) evaluating the combined values according to the maximum likelihood method, and detecting the signals transmitted from the transmitter.
  • a method for receiving signals in a MIMO system including a receiver for receiving signals from a transmitter through multiple transmit channels wherein the transmitter includes multiple transmit antennas and the receiver includes multiple receive antennas, comprises: (a) receiving multipath signals through the multiple receive antennas, and estimating respective transmit channel parameters that show states of the multiple transmit channels; (b) comparing the respective estimated transmit channel parameters, and determining the transmit antenna corresponding to the transmit channel with the best state from among the multiple transmit antennas of the transmitter; (c) feeding the determined transmit antenna information back to the transmitter through a specific feedback path; (d) linearly combining the received signals, and outputting results; and (e) evaluating the received signals according to the maximum likelihood method, and detecting the signals transmitted from the transmitter.
  • a transmit power allocation method in a MIMO system including a transmitter and a receiver for receiving signals from the transmitter through multiple transmit channels wherein the transmitter includes multiple transmit antennas and the receiver includes multiple receive antennas, comprises: (a) the receiver receiving multipath signals through the multiple receive antennas, and estimating respective transmit channel parameters that show states of the multiple transmit channels; (b) the receiver comparing the respective estimated transmit channel parameters, determining the transmit antenna corresponding to the transmit channel with the best state from among the multiple transmit antennas of the transmitter, and feeding the determined transmit antenna information back to the transmitter through a specific feedback path; (c) the transmitter applying weights so that the maximum power may be applied to the signal supplied to the transmit antenna detected from the information fed back from the receiver in (b) from among the signals to be transmitted to the receiver; and (d) the transmitter transmitting the weight-applied signal to the receiver through the multiple transmit antennas.
  • FIG. 1 shows a block diagram of a MIMO closed-loop space-time block encoding system according to a preferred embodiment of the present invention
  • FIG. 2 shows a detailed block diagram of a channel estimator and channel state comparator unit shown in FIG. 1
  • FIG. 3 shows a detailed block diagram of a weight supplier shown in FIG. 1
  • FIG. 1 shows a block diagram of a MIMO closed-loop space-time block encoding system according to a preferred embodiment of the present invention
  • FIG. 2 shows a detailed block diagram of a channel estimator and channel state comparator unit shown in FIG. 1
  • FIG. 3 shows a detailed block diagram of a weight supplier shown in FIG. 1
  • FIG. 1 shows a block diagram of a MIMO closed-loop space-time block encoding system according to a preferred embodiment of the present invention
  • FIG. 2 shows a detailed block diagram of a channel estimator and channel state comparator unit shown in FIG. 1
  • FIG. 3 shows a detailed block diagram of a weight supplier shown in FIG
  • FIG. 4 shows simulation results of comparing performance when a power allocation method according to a preferred 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, with performance of a conventional open-loop space-time block encoding system.
  • FIG. 1 shows a block diagram of the MIMO closed-loop space-time block encoding system according to a preferred embodiment of the present invention.
  • the MIMO closed-loop space-time block encoding system comprises a transmitter 100 and a receiver 200.
  • the transmitter 100 comprises an information source 110, a space- time block encoder 120, a weight supplier 130, and a transmit antenna 140; and the receiver 200 comprises a receive antenna 210, a channel estimator and channel state comparator unit 220, a combiner 230, and a maximum likelihood detector 240.
  • the information source 110 provides symbols (x l ,x 2 ,...,x k ) to be
  • the space-time block encoder 120 maps the
  • the weight supplier 130 determines weights according to information fed back from the receiver through a feedback path, and
  • the weight supplier 130 establishes the weight that corresponds to the signal input to the transmit antenna having a good channel state fed back from the receiver 200 as 1 , and establishes weights that correspond to signals input to other transmit antennas as 0. In this instance, the establishment of the weight as 1 represents that the transmit power is allocated to the signals having the weights of 1 , and no transmit power is allocated to the signals having the weights of 0.
  • the transmit antenna 140 includes a plurality n ⁇ of transmission
  • the transmit antenna 140 that receives the signals with the established weights of 1 from among the signals output by the space-time block encoder 120 transmits the corresponding signal to the receiver 200 in the maximum transmit power level.
  • the transmit antenna 140 for transmitting the signal with the maximum transmit power can also be changed according to the variation of the channel states. Since the channel states are varied for each block unit time of the space- time block code, the transmit antenna 140 for transmitting the signal having the weight established as 1 can be changed for each block unit time of the space-time block code.
  • the receive antenna 210 of the receiver 200 includes a plurality n R
  • the channel estimator and channel state comparator unit 220 receives the multipath signal through the receive antenna 210, estimates parameters of the channels, compares the channel states determined through the estimated parameters of the channels to determine transmit antenna information of the best channel state, and feed it back to the transmitter 100 through the feedback path.
  • the combiner 230 linearly combines the respective signals output through the channel estimator and channel state comparator unit 220 to generate estimates which are combined with higher reliabilities than the received signals.
  • the maximum likelihood detector 240 estimates the values combined and output by the combiner 230 according to the maximum likelihood method to detect the symbols transmitted by the transmitter 100.
  • FIG. 2 shows a detailed block diagram of the channel estimator and channel state comparator unit 220 shown in FIG. 1. As shown, the channel estimator and channel state comparator unit 220 comprises a channel estimator 222 and a channel state comparator 224.
  • the channel estimator 222 uses n R signals received through the
  • the channel state comparator 224 uses the parameters of the respective channels estimated by the channel estimator 222 to compare the states of the respective channels, and determines the transmit channel having the best channel state, that is, the transmit antenna 140, and provides determined channel information to the weight supplier 130 of the transmitter 100 through a feedback path. In this instance, the states of the transmit channels are determined by comparing sizes of the channel parameters estimated for respective channels.
  • FIG. 3 shows a detailed block diagram of a weight supplier shown in
  • the weight supplier 130 comprises a weight determiner
  • the weight determiner 132 determines respective weights
  • the weight determiner 132 determines the weight that corresponds to the signal to be input to the transmit antenna 140, the signal being detected from the channel state information fed back from the channel state comparator 224, as 1 , and weights that correspond to other signals as 0.
  • the multipliers 134-1 through 134- « r multiply the respective weights
  • the weight determiner 132 determines the weight to be corresponded to the respective signals output by the space-time block encoder 120, and respectively output results to the transmit antenna 140.
  • the single weight is determined as 1 by the weight determiner 132, the weight is multiplied by the single signal output by the space-time block encoder 120, a maximum power is allocated, and the
  • the transmitter 100 are input to the space-time block encoder 120 to
  • source 1 10 have a format of the real number constellation. Power is allocated to the space-time block code signals generated
  • space-time block code signals are propagated through the transmit antenna
  • weight v soir ⁇ represents a weight of the t-th transmit antenna. Since the power
  • n R transmit antennas 140 is to be always 1 for each signal
  • Equation 1 Equation 1
  • the receiver 200 completely estimates the parameters of the channels and coherently detects the received signals.
  • n R receive antennas receive the signals that have passed through the fading
  • the combiner 230 combines the received signals to produce
  • the space-time block codes have different configurations depending on whether the space-time block codes have a square format (the combiner 230 generates square space-time block codes when the number of the transmit antennas is 2, 4, and 8) or a non-square format (the combiner 230 generates non-square space-time block codes when the number of the transmit antennas is 3, 5, 6, and 7).
  • the space-time block codes have a square format (the combiner 230 generates square space-time block codes when the number of the transmit antennas is 2, 4, and 8) or a non-square format (the combiner 230 generates non-square space-time block codes when the number of the transmit antennas is 3, 5, 6, and 7).
  • r Jt is a signal received at the j-th receive antenna 210 in the t-
  • ⁇ t (i) is a position of the row including x, in the t-th column of
  • ⁇ t ( ⁇ ) is a code of x t at the t-th
  • ⁇ ( ⁇ ) is a set of columns including x, in the space-time block
  • Equation 2 Equation 2
  • Equation 4 Equation 4
  • Equation 3 Equation 5
  • Equation 4 the output signal 3c, of the combiner 230 as
  • Equation 4 Equation 4
  • the weight supplier 130 does not
  • a receive SNR is maximized so as to guarantee the optimized BER to the receiver 200.
  • the transmitter 100 allocates the transmit power to be allocated to the respective transmit antennas 140 so as to maximize the receive SNR of the receiver 200 in the MIMO closed-loop space-time block encoding system.
  • the receive SNR is induced as Equation 6 from Equations 4 and 5. Equation 6
  • Equation 6 for the square and non-square space-time block codes. Equation 6 is also given as Equation 7. Equation 7 where a t is an order of the transmit antenna 140 having the t-th
  • transmit antennas 140 has the second best channel state, a 2 becomes 4.
  • Equation 9 By putting Equation 9 to Equation 7, the receive SNR at the receiver
  • the receive SNR is a function depending on the weights fl2 ,v ⁇ 3 ,...,v ⁇ n of the transmit antenna 140.
  • the receive SNR is a function depending on the weights fl2 ,v ⁇ 3 ,...,v ⁇ n of the transmit antenna 140.
  • Equation 11 the condition for maximizing the receive SNR is to allocate the
  • the power allocation method for the MIMO closed-loop space-time block encoding system is to select the transmit antenna 140 with the best channel state from among the multiple transmit antennas 140, allocate all the transmit power to the corresponding antenna, and allocate no power to other transmit antennas 140.
  • the channel estimator and channel state comparator unit 220 of the receiver 200 estimates the channel states according to each change of the channel state, compares the respective estimated channel states to determine which transmit antenna 140 has the best channel state, and feeds determination information back through the feedback path between the receiver 200 and the transmitter 100.
  • FIG. 4 shows simulation results of comparing performance when a power allocation method according to a preferred 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, with performance of a conventional open-loop space-time block encoding system.
  • the conventional open-loop space-time block encoding system having four transmit antennas and one receive antenna needs a transmit a SNR of about 10dB so as to achieve 10 "3 BER, but the MIMO closed-loop space-time block encoding system according to the preferred embodiment of the present invention requires the transmit SNR to be substantially 7.5dB which is less than the conventional one.
  • the receiver 200 estimates channel parameters from the received signals, compares the estimated channel parameters, determines the transmit antenna 140 with the best channel state, and feeds the transmit antenna back to the transmitter 100 through a feedback path.
  • the transmitter 100 establishes the weight of 1 for the signal supplied to the corresponding transmit antenna 140 according to the information on the transmit antenna fed back from the receiver 200, and without being restricted to this technical scope, when the receiver 200 estimates the channel parameters from the received signals, it feeds the estimated channel parameters back to the transmitter through the feedback path, and the transmitter 100 compares various types of channel parameter information fed back from the receiver 200, determines the transmit antenna 140 with the best channel state, and assigns the weight of 1 to the determined transmit antenna 10.
  • the receive SNR of the receiver is maximized in the MIMO closed-loop space-time block encoding system, and hence, improved BER is guaranteed.

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Abstract

Disclosed is a transmitter (100) of a MIMO (multiple input multiple output) system wherein the transmitter (100) transmits signals to a receiver (200) through multiple transmit channels, the transmitter (100) includes multiple transmit antennas (140), and the receiver (200) includes multiple receive antennas (210). The transmitter (100) comprises: a space time block encoder (120) for performing space time block encoding on signals to be transmitted to the receiver (200), and generating signals to be transmitted through the multiple transmit antennas (140); and a weight supplier (130) for applying weights so that the maximum power may be allocated to the signal supplied to the transmit antenna (140) corresponding to the channel with the best transmit channel state from among the signals output from the space time block encoder (120), and outputting it to the multiple transmit antenna. The multiple transmit antenna (140) receives the signal to which power is allocated from the weight supplier (130), and transmits the signal to the receiver (200).

Description

TRANSMITTING AND RECEIVING DEVICE AND METHOD FOR CLOSED LOOP SPACE TIME BLOCK CODING SYSTEM HAVING MULTIPLE INPUT MULTIPLE OUTPUT ANTENNA, AND TRANSMIT POWER ALLOCATION METHOD FOR THE SYSTEM
CROSS REFERENCE TO RELATED APPLICATION
This application claims priority to and the benefit of Korea Patent Application No. 2003-57846 filed on August 21 , 2003 in the Korean Intellectual Property Office, the content of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
(a) Field of the Invention The present invention relates to a MIMO (multiple input multiple output) system for using a multiple antenna at a transmit terminal and a multiple antenna at a receive terminal. More specifically, the present invention relates to a transmitting and receiving device and method of a closed-loop space-time block encoding system that uses space-time block codes developed for a MIMO system.
(b) Description of the Related Art
Space-time block codes proposed for the MIMO radio communication system provide the maximum diversity gain to the same system through a simple linear combination method at a receiver. Since the conventional MIMO space-time block encoding system using the time-space block codes allocates the same amount of weights to antennas equally even though the channel states corresponding to the respective antennas are different, the same amount of transmit power is problematically applied to a plurality of transmit antennas. That is, since limited transmit power is provided to antennas with bad channel states, cases where more power is allocated to antennas with good channel states to increase efficiencies of transmit power distribution are not extant, which may be desirable from the viewpoint of complexity of the transmitting and receiving system, but which is not desirable from the viewpoint of efficiencies of transmit power that is the most important factor in the radio communication system.
SUMMARY OF THE INVENTION
It is an advantage of the present invention to provide a transmitting and receiving device and method of a closed-loop space-time block encoding system having a plurality of transmit/receive antennas for allocating transmit power of a transmitter so as to optimize BER (bit error rate) performance at a receiver. In one aspect of the present invention, a transmitter of a MIMO system wherein the transmitter transmits signals to a receiver through multiple transmit channels, the transmitter includes multiple transmit antennas, and the receiver includes multiple receive antennas, comprises: a space time block encoder for performing space time block encoding on signals to be transmitted to the receiver, and generating signals to be transmitted through the multiple transmit antennas; and a weight supplier for applying weights so that the maximum power may be allocated to the signal that is supplied to the transmit antenna that corresponds to the channel with the best transmit channel state from among the signals output from the space time block encoder, and outputting it to the multiple transmit antenna, and the multiple transmit antenna receiving the signal to which power is allocated from the weight supplier, and transmitting the signal to the receiver. The weight supplier comprises: a weight determiner for determining respective weights to be applied to the signals which are output from the space time block encoder based on the states of the transmit channel; and a multiplier for multiplying the respective weights determined by the weight determiner by the respective signals output by the space time block encoder, and outputting multiplication results to the corresponding transmit antennas. The transmit antenna information corresponding to the channel with the best transmit channel state is determined by comparing the parameters of the transmit channels estimated by the receiver, and fed back to the transmitter from the receiver through a specific feedback path. The transmit antenna information corresponding to the channel with the best transmit channel state is determined by the transmitter by comparing the transmit channel parameters estimated by the receiver and transmitted through the specific feedback path. The summation of the weights is 1 , and the weight supplier establishes the weight applied to the signal supplied to the transmit antenna corresponding to the channel with the best transmit channel state as 1 , and the weights applied to other signals as 0 so that the maximum power may be allocated to the signal supplied to the transmit antenna corresponding to the channel with the best transmit channel state. The transmit antenna corresponding to the channel with the best transmit channel state is determined as a space time block code unit according to a change of the space time block code unit of the transmit channel state. In another aspect of the present invention, a receiver of a MIMO system wherein the receiver receives signals from a transmitter through multiple transmit channels, the transmitter includes multiple transmit antennas, and the receiver includes multiple receive antennas, comprises: a channel estimator for receiving multipath signals through the multiple receive antennas, estimating respective transmit channel parameters that show states of the multiple transmit channels, and feeding the respective estimated transmit channel parameters to the transmitter through a specific feedback path; a combiner for linearly combining the respective signals output by the channel estimator; and a maximum likelihood detector for evaluating the values output by the combiner according to the maximum likelihood method, and detecting the signals transmitted from the transmitter. In another aspect of the present invention, a receiver of a MIMO system wherein the receiver receives signals from a transmitter through multiple transmit channels, the transmitter includes multiple transmit antennas, and the receiver includes multiple receive antennas, comprises: a channel estimator and channel state comparator unit for receiving multipath signals through the multi receive antennas, estimating respective transmit channel parameters that show states of the multi transmit antennas, comparing the respective estimated transmit channel parameters, determining the transmit antenna corresponding to the transmit channel with the best state from among the multiple transmit antennas of the transmitter, and feeding it to the transmitter through a specific feedback path; a combiner for linearly combining the respective signals output by the channel estimator and channel state comparator unit, and outputting results; and a maximum likelihood detector for evaluating the values output by the combiner according to the maximum likelihood method, and detecting the signals transmitted from the transmitter. The channel estimator and channel state comparator unit comprises: a channel estimator for using the multipath signals received through the multiple receive antennas, and estimating transmit channel parameters that show respective states of the multiple transmit channels; and a channel state comparator for respectively comparing the respective transmit channel parameters estimated by the channel estimator, determining the transmit antenna corresponding to the transmit channel with the best state, and feeding it back to the transmitter through the specific feedback path. The channel estimator and channel state comparator unit compares sizes of the estimated transmit channel parameters, and determines the transmit antenna with the best transmit channel state. The transmit channel parameters are determined by a space time block code unit according to changes of the space time block code unit of the transmit channel state. The transmit antenna corresponding to the channel with the best transmit channel state is determined by a space time block code unit according to changes of the space time block code unit of the transmit channel state. In still another aspect of the present invention, a method for transmitting signals in a MIMO system including a transmitter for transmitting signals to a receiver through multiple transmit channels wherein the transmitter includes multiple transmit antennas and the receiver includes multiple receive antennas, comprises: (a) performing space time block encoding on signals to be transmitted to the receiver, and generating signals to be transmitted through the multiple transmit antenna; (b) applying weights so that the maximum power may be allocated to the signal supplied to the transmit antenna corresponding to the channel with the best transmit channel state from among the generated signals; and (c) transmitting the weight-applied signals to the receiver through the multiple transmit antennas. In still yet another aspect of the present invention, a method for receiving signals in a MIMO system including a receiver for receiving signals from a transmitter through multiple transmit channels wherein the transmitter includes multiple transmit antennas and the receiver includes multiple receive antennas, comprises: (a) receiving multipath signals through the multi receive antennas, and estimating respective transmit channel parameters that show states of the multiple transmit channels; (b) feeding the respective estimated transmit channel parameters back to the transmitter through a specific feedback path; (c) linearly combining the received signals, and outputting results; and (d) evaluating the combined values according to the maximum likelihood method, and detecting the signals transmitted from the transmitter. In still further another aspect of the present invention, a method for receiving signals in a MIMO system including a receiver for receiving signals from a transmitter through multiple transmit channels wherein the transmitter includes multiple transmit antennas and the receiver includes multiple receive antennas, comprises: (a) receiving multipath signals through the multiple receive antennas, and estimating respective transmit channel parameters that show states of the multiple transmit channels; (b) comparing the respective estimated transmit channel parameters, and determining the transmit antenna corresponding to the transmit channel with the best state from among the multiple transmit antennas of the transmitter; (c) feeding the determined transmit antenna information back to the transmitter through a specific feedback path; (d) linearly combining the received signals, and outputting results; and (e) evaluating the received signals according to the maximum likelihood method, and detecting the signals transmitted from the transmitter. In still further another aspect of the present invention, a transmit power allocation method in a MIMO system including a transmitter and a receiver for receiving signals from the transmitter through multiple transmit channels wherein the transmitter includes multiple transmit antennas and the receiver includes multiple receive antennas, comprises: (a) the receiver receiving multipath signals through the multiple receive antennas, and estimating respective transmit channel parameters that show states of the multiple transmit channels; (b) the receiver comparing the respective estimated transmit channel parameters, determining the transmit antenna corresponding to the transmit channel with the best state from among the multiple transmit antennas of the transmitter, and feeding the determined transmit antenna information back to the transmitter through a specific feedback path; (c) the transmitter applying weights so that the maximum power may be applied to the signal supplied to the transmit antenna detected from the information fed back from the receiver in (b) from among the signals to be transmitted to the receiver; and (d) the transmitter transmitting the weight-applied signal to the receiver through the multiple transmit antennas.
BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate an embodiment of the invention, and, together with the description, serve to explain the principles of the invention: FIG. 1 shows a block diagram of a MIMO closed-loop space-time block encoding system according to a preferred embodiment of the present invention; FIG. 2 shows a detailed block diagram of a channel estimator and channel state comparator unit shown in FIG. 1 ; FIG. 3 shows a detailed block diagram of a weight supplier shown in FIG. 1 ; and FIG. 4 shows simulation results of comparing performance when a power allocation method according to a preferred 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, with performance of a conventional open-loop space-time block encoding system.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following detailed description, only the preferred embodiment of the invention has been shown and described, simply by way of illustration of the best mode contemplated by the inventor(s) of carrying out the invention. As will be realized, the invention is capable of modification in various obvious respects, all without departing from the invention. Accordingly, the drawings and description are to be regarded as illustrative in nature, and not restrictive. A MIMO closed-loop space-time block encoding system according to a preferred embodiment of the present invention will be described with reference to drawings. FIG. 1 shows a block diagram of the MIMO closed-loop space-time block encoding system according to a preferred embodiment of the present invention. As shown, the MIMO closed-loop space-time block encoding system comprises a transmitter 100 and a receiver 200. The transmitter 100 comprises an information source 110, a space- time block encoder 120, a weight supplier 130, and a transmit antenna 140; and the receiver 200 comprises a receive antenna 210, a channel estimator and channel state comparator unit 220, a combiner 230, and a maximum likelihood detector 240.
The information source 110 provides symbols (xl,x2,...,xk) to be
transmitted to the receiver 200, the space-time block encoder 120 maps the
symbols (xx,x2,...,xk) to space-time block codes to generate symbols
encoded by the space-time block codes, and outputs the generated symbols to paths with the same number of the transmit antennas 140 for transmission diversity. The weight supplier 130 determines weights according to information fed back from the receiver through a feedback path, and
provides corresponding weights (v,,v2, 3,..., ) to respective signals output
by the space-time block encoder 120 to allocate the transmit power. The weight supplier 130 establishes the weight that corresponds to the signal input to the transmit antenna having a good channel state fed back from the receiver 200 as 1 , and establishes weights that correspond to signals input to other transmit antennas as 0. In this instance, the establishment of the weight as 1 represents that the transmit power is allocated to the signals having the weights of 1 , and no transmit power is allocated to the signals having the weights of 0. The transmit antenna 140 includes a plurality nτ of transmission
antennas, and transmits signals which are output by the space-time block encoder 120 and to which the weights are provided to the receiver 200. The transmit antenna 140 that receives the signals with the established weights of 1 from among the signals output by the space-time block encoder 120 transmits the corresponding signal to the receiver 200 in the maximum transmit power level. In this instance, since the information fed back from the receiver 200 can be modified according to variation of the channel states, the transmit antenna 140 for transmitting the signal with the maximum transmit power can also be changed according to the variation of the channel states. Since the channel states are varied for each block unit time of the space- time block code, the transmit antenna 140 for transmitting the signal having the weight established as 1 can be changed for each block unit time of the space-time block code. The receive antenna 210 of the receiver 200 includes a plurality nR
of reception antennas, and receives signals from the transmitter 100 through a multipath channel. The channel estimator and channel state comparator unit 220 receives the multipath signal through the receive antenna 210, estimates parameters of the channels, compares the channel states determined through the estimated parameters of the channels to determine transmit antenna information of the best channel state, and feed it back to the transmitter 100 through the feedback path. The combiner 230 linearly combines the respective signals output through the channel estimator and channel state comparator unit 220 to generate estimates which are combined with higher reliabilities than the received signals. The maximum likelihood detector 240 estimates the values combined and output by the combiner 230 according to the maximum likelihood method to detect the symbols transmitted by the transmitter 100. FIG. 2 shows a detailed block diagram of the channel estimator and channel state comparator unit 220 shown in FIG. 1. As shown, the channel estimator and channel state comparator unit 220 comprises a channel estimator 222 and a channel state comparator 224.
The channel estimator 222 uses nR signals received through the
receive antenna 210 to estimate parameters that show respective states of the transmit channels formed between the transmit antenna 140 of the transmitter 100 and the receive antenna 210 of the receiver 200. Since the channel estimation follows the conventional channel estimation method, no further description will be provided. The channel state comparator 224 uses the parameters of the respective channels estimated by the channel estimator 222 to compare the states of the respective channels, and determines the transmit channel having the best channel state, that is, the transmit antenna 140, and provides determined channel information to the weight supplier 130 of the transmitter 100 through a feedback path. In this instance, the states of the transmit channels are determined by comparing sizes of the channel parameters estimated for respective channels. That is, the parameter that is estimated to have the biggest channel parameter becomes the channel with the best state, and the transmit antenna 140 for transmitting a signal through this channel is determined as final information, and the final information is fed back to the weight supplier 130 of the transmitter 100. FIG. 3 shows a detailed block diagram of a weight supplier shown in
FIG. 1. As shown, the weight supplier 130 comprises a weight determiner
132 and a plurality nτ of multipliers 134-1 through 134-«r .
The weight determiner 132 determines respective weights
(vx,v2,v3,...,vltτ) corresponding to the respective signals output by the space-
time block encoder 120 based on the channel state information fed back from the channel estimator and channel state comparator unit 220 of the receiver 200. The weight determiner 132 determines the weight that corresponds to the signal to be input to the transmit antenna 140, the signal being detected from the channel state information fed back from the channel state comparator 224, as 1 , and weights that correspond to other signals as 0.
The multipliers 134-1 through 134-«r multiply the respective weights
determined by the weight determiner 132 to be corresponded to the respective signals output by the space-time block encoder 120, and respectively output results to the transmit antenna 140. As described, as the single weight is determined as 1 by the weight determiner 132, the weight is multiplied by the single signal output by the space-time block encoder 120, a maximum power is allocated, and the
maximum power is transmitted through a single transmit antenna 140 with
the best channel state, the SNR (signal to noise ratio) at the receiver 200 is
maximized, and the BER at the receiver 200 is optimized. A power allocation method in a MIMO closed-loop space-time block
encoding system will now be described.
The symbols (xl,x2,...,xk) provided by the information source 1 10 of
the transmitter 100 are input to the space-time block encoder 120 to
generate space-time block codes. The symbols provided by the information
source 1 10 have a format of the real number constellation. Power is allocated to the space-time block code signals generated
by the space-time block encoder by the weight supplier 130 before the
space-time block code signals are propagated through the transmit antenna
140. The respective weights v1,v2,v3,...,v are multiplied by the respective
signals output by the space-time block encoder 120 by the multiplier. The
weight v„τ represents a weight of the t-th transmit antenna. Since the power
transmitted by the nR transmit antennas 140 is to be always 1 for each signal
transmission time, the respective weights v, ,v2,v3,...,v„ are to satisfy
Equation 1. Equation 1
V2l + V22 H r- V2„T = 1
The signals to which the power is allocated through the weight supplier 130 are transmitted to the receiver 200 through the transmit antenna 140. The signals transmitted from the transmitter 100 undergo fading channels with different paths. Characteristics of the wireless fading channels
are indicated with complex parameters hy which represent channel states
between the i-th transmit antenna 140 and the j-th receive antenna 210. Determination of goodness and badness of the channel states is performed
by comparing size information of the channel parameters hy . It is assumed
in the preferred embodiment that the receiver 200 completely estimates the parameters of the channels and coherently detects the received signals. The
nR receive antennas receive the signals that have passed through the fading
channels, and the combiner 230 combines the received signals to produce
output signals 3c, shown in Equation 2 or 3 according to the maximum
likelihood detection principle. The output signals 3c, by the combiner 230
have different configurations depending on whether the space-time block codes have a square format (the combiner 230 generates square space-time block codes when the number of the transmit antennas is 2, 4, and 8) or a non-square format (the combiner 230 generates non-square space-time block codes when the number of the transmit antennas is 3, 5, 6, and 7). The
output signal 3c, in the case of the square space-time block codes is given in
Equation 2. Equation 2
Figure imgf000017_0001
where rJt is a signal received at the j-th receive antenna 210 in the t-
th time interval, εt(i) is a position of the row including x, in the t-th column of
the received space-time block code, and δt(ϊ) is a code of xt at the t-th
column of the space-time block code. The output signal 3c, in the case of the non-square space-time block
codes is given in Equation 3. Equation 3
Figure imgf000018_0001
where η(ϊ) is a set of columns including x, in the space-time block
code. By substituting the receive signal rβ in Equations 2 and 3, Equation
2 is given as Equation 4, and Equation 3 is given as Equation 5. As a result,
the output signal 3c, of the combiner 230 as to the square space-time block
codes is given in Equation 4, and the output signal 3c, of the combiner 230 as
to the non-square space-time block codes is given in Equation 5. Equation 4
*» =ΣΣ \\\ v?k + ΣΣtø( Vζω.Λ J Equation 5 »T »R - jκ, + Σ J Wn irΛ )) t=\ j=l teη(,) J=l As described, the signal 3c, combined and output by the combiner 230 is input to the maximum likelihood detector 240 for symbol detection,
and the maximum likelihood detector 240 evaluates the input signal 3c, and
generates a final detection signal Jc, .
In the above-described equations, the weight supplier 130 does not
designate the weights vl,v2,v3,...,vnτ with specific values, and the
designation of the weights v,,v2,v3,...,v„r with specific values is the method
for allocating power to the channels. A method for obtaining the optimal BER
from the receiver 200 by designating the weights v1,v2,v3,..., will now be
described. A receive SNR is maximized so as to guarantee the optimized BER to the receiver 200. Hence, the transmitter 100 allocates the transmit power to be allocated to the respective transmit antennas 140 so as to maximize the receive SNR of the receiver 200 in the MIMO closed-loop space-time block encoding system. First, the receive SNR is induced as Equation 6 from Equations 4 and 5. Equation 6
Figure imgf000019_0001
where γ is the symbol's transmit SNT. The receive SNR is given as
Equation 6 for the square and non-square space-time block codes. Equation 6 is also given as Equation 7. Equation 7
Figure imgf000020_0001
where at is an order of the transmit antenna 140 having the t-th
good channel state. For example, when the third transmit antenna from
among the multiple transmit antennas 140 has the best channel state, aλ
becomes 3, and when the fourth transmit antenna from among the multiple
transmit antennas 140 has the second best channel state, a2 becomes 4.
Big and small relations of the channel states are given in Equation 8. Equation 8
Figure imgf000020_0002
Since the total power transmitted by the multiple transmit antennas
140 must be 1 , the weights are required to satisfy Equation 1. Arrangement
of Equation 1 with respect to at gives Equation 9.
Equation 9
Figure imgf000020_0003
By putting Equation 9 to Equation 7, the receive SNR at the receiver
200 is given as Equation 10. Equation 10
Figure imgf000020_0004
Based on Equation 10, the receive SNR is a function depending on the weights fl2,vθ3,...,vαn of the transmit antenna 140. The receive SNR
reduces when any values except the value of 0 are weighted to the weights
vaι,va^ ,...,van because coefficients of the respective weights vai,va^ ,...,va
become negative in Equation 10 according to Equation 8. Therefore, it is
needed to establish the weights v ,v ,...,v of the transmit antenna 140 as
0 so as to maximize the receive SNR, with reference to Equation 10. As a result, Equation 10 is given as Equation 11. Equation 11 OIL , SNRreceived ≤ Σ αι7 7 7=1 where h is a parameter for indicating a channel state between the
α th transmit antenna 140 and the j-th receive antenna 210. Referring to
Equation 11 , the condition for maximizing the receive SNR is to allocate the
weight of 0 to all the transmit antennas 140 except the a -th transmit
antenna 140 with the best channel state, and allocate the weight of 1 to the
β, -th transmit antenna 140 with the best channel state. That is, the optimized
power allocation method for the MIMO closed-loop space-time block encoding system is to select the transmit antenna 140 with the best channel state from among the multiple transmit antennas 140, allocate all the transmit power to the corresponding antenna, and allocate no power to other transmit antennas 140. In this instance, since the channel states are changed for each block unit time of the space-time block codes, the channel estimator and channel state comparator unit 220 of the receiver 200 estimates the channel states according to each change of the channel state, compares the respective estimated channel states to determine which transmit antenna 140 has the best channel state, and feeds determination information back through the feedback path between the receiver 200 and the transmitter 100. The above-noted power allocation method requires less operation for obtaining feedback information from the receiver 200, and a lesser bit number of the fed back information, and accordingly, the same method has good characteristics against influences of time delay caused by the feedback. FIG. 4 shows simulation results of comparing performance when a power allocation method according to a preferred 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, with performance of a conventional open-loop space-time block encoding system. Referring to FIG. 4, the conventional open-loop space-time block encoding system having four transmit antennas and one receive antenna needs a transmit a SNR of about 10dB so as to achieve 10"3 BER, but the MIMO closed-loop space-time block encoding system according to the preferred embodiment of the present invention requires the transmit SNR to be substantially 7.5dB which is less than the conventional one. While this invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. For example, in the above, the receiver 200 estimates channel parameters from the received signals, compares the estimated channel parameters, determines the transmit antenna 140 with the best channel state, and feeds the transmit antenna back to the transmitter 100 through a feedback path. The transmitter 100 establishes the weight of 1 for the signal supplied to the corresponding transmit antenna 140 according to the information on the transmit antenna fed back from the receiver 200, and without being restricted to this technical scope, when the receiver 200 estimates the channel parameters from the received signals, it feeds the estimated channel parameters back to the transmitter through the feedback path, and the transmitter 100 compares various types of channel parameter information fed back from the receiver 200, determines the transmit antenna 140 with the best channel state, and assigns the weight of 1 to the determined transmit antenna 10. The above-noted process of comparison and determination will be easily understood by a skilled person. According to the present invention, the receive SNR of the receiver is maximized in the MIMO closed-loop space-time block encoding system, and hence, improved BER is guaranteed.

Claims

WHAT IS CLAIMED IS:
1. A transmitter of a MIMO (multiple input multiple output) system wherein the transmitter transmits signals to a receiver through multiple transmit channels, the transmitter includes multiple transmit antennas, and the receiver includes multiple receive antennas, the transmitter comprising: a space time block encoder for performing space time block encoding on signals to be transmitted to the receiver, and generating signals to be transmitted through the multiple transmit antennas; and a weight supplier for applying weights so that the maximum power may be allocated to the signal that is supplied to the transmit antenna that corresponds to the channel with the best transmit channel state from among the signals output from the space time block encoder, and outputting it to the multiple transmit antenna, and the multiple transmit antenna receiving the signal to which power is allocated from the weight supplier, and transmitting the signal to the receiver.
2. The transmitter of claim 1 , wherein the weight supplier comprises: a weight determiner for determining respective weights to be applied
to the signals which are output from the space time block encoder based on
the states of the transmit channel; and a multiplier for multiplying the respective weights determined by the
weight determiner by the respective signals output by the space time block
encoder, and outputting multiplication results to the corresponding transmit
antennas.
3. The transmitter of claim 1 or 2, wherein the transmit antenna information corresponding to the channel with the best transmit channel state is determined by comparing the parameters of the transmit channels estimated by the receiver, and fed back to the transmitter from the receiver through a specific feedback path.
4. The transmitter of claim 1 or 2, wherein the transmit antenna information corresponding to the channel with the best transmit channel state is determined by the transmitter by comparing the transmit channel parameters estimated by the receiver and transmitted through the specific feedback path.
5. The transmitter of claim 1 or 2, wherein the summation of the weights is 1 , and the weight supplier establishes the weight applied to the signal supplied to the transmit antenna corresponding to the channel with the best transmit channel state as 1 , and the weights applied to other signals as 0 so that the maximum power may be allocated to the signal supplied to the transmit antenna corresponding to the channel with the best transmit channel state.
6. The transmitter of claim 1 or 2, wherein the transmit antenna corresponding to the channel with the best transmit channel state is determined as a space time block code unit according to a change of the space time block code unit of the transmit channel state.
7. A receiver of a MIMO (multiple input multiple output) system wherein the receiver receives signals from a transmitter through multiple transmit channels, the transmitter includes multiple transmit antennas, and the receiver includes multiple receive antennas, the receiver comprising: a channel estimator for receiving multipath signals through the multiple receive antennas, estimating respective transmit channel parameters that show states of the multiple transmit channels, and feeding the respective estimated transmit channel parameters to the transmitter through a specific feedback path; a combiner for linearly combining the respective signals output by the channel estimator; and a maximum likelihood detector for evaluating the values output by the combiner according to the maximum likelihood method, and detecting the signals transmitted from the transmitter.
8. A receiver of a MIMO (multiple input multiple output) system wherein the receiver receives signals from a transmitter through multiple transmit channels, the transmitter includes multiple transmit antennas, and the receiver includes multiple receive antennas, the receiver comprising: a channel estimator and channel state comparator unit for receiving multipath signals through the multi receive antennas, estimating respective transmit channel parameters that show states of the multi transmit antennas, comparing the respective estimated transmit channel parameters, determining the transmit antenna corresponding to the transmit channel with the best state from among the multiple transmit antennas of the transmitter, and feeding it to the transmitter through a specific feedback path; a combiner for linearly combining the respective signals output by the channel estimator and channel state comparator unit, and outputting results; and a maximum likelihood detector for evaluating the values output by the combiner according to the maximum likelihood method, and detecting the signals transmitted from the transmitter.
9. The receiver of claim 8, wherein the channel estimator and channel state comparator unit comprises: a channel estimator for using the multipath signals received through the multiple receive antennas, and estimating transmit channel parameters that show respective states of the multiple transmit channels; and a channel state comparator for respectively comparing the respective transmit channel parameters estimated by the channel estimator, determining the transmit antenna corresponding to the transmit channel with the best state, and feeding it back to the transmitter through the specific feedback path.
10. The receiver of claim 8 or 9, wherein the channel estimator and channel state comparator unit compares sizes of the estimated transmit channel parameters, and determines the transmit antenna with the best transmit channel state.
11. The receiver of claim 7, wherein the transmit channel parameters are determined by a space time block code unit according to changes of the space time block code unit of the transmit channel state.
12. The receiver of claim 8 or 9, wherein the transmit antenna corresponding to the channel with the best transmit channel state is determined by a space time block code unit according to changes of the space time block code unit of the transmit channel state.
13. A method for transmitting signals in a MIMO (multiple input
multiple output) system including a transmitter for transmitting signals to a
receiver through multiple transmit channels wherein the transmitter includes
multiple transmit antennas and the receiver includes multiple receive
antennas, the method comprising:
(a) performing space time block encoding on signals to be
transmitted to the receiver, and generating signals to be transmitted through the multiple transmit antenna; (b) applying weights so that the maximum power may be allocated to the signal supplied to the transmit antenna corresponding to the channel with
the best transmit channel state from among the generated signals; and
(c) transmitting the weight-applied signals to the receiver through the multiple transmit antennas.
14. The method of claim 13, wherein transmit antenna information
corresponding to the channel with the best transmit channel state is
determined by comparing the parameters of the transmit channels estimated
by the receiver, and fed back from the receiver through a specific feedback
path.
15. The method of claim 13, wherein the transmit antenna
information corresponding to the channel with the best transmit channel state
is determined by the transmitter by comparing the transmit channel
parameters estimated by the receiver and transmitted through the specific
feedback path.
16. A method for receiving signals in a MIMO (multiple input multiple output) system including a receiver for receiving signals from a transmitter through multiple transmit channels wherein the transmitter includes multiple transmit antennas and the receiver includes multiple receive antennas, the method comprising: (a) receiving multipath signals through the multi receive antennas, and estimating respective transmit channel parameters that show states of the multiple transmit channels; (b) feeding the respective estimated transmit channel parameters back to the transmitter through a specific feedback path; (c) linearly combining the received signals, and outputting results; and (d) evaluating the combined values according to the maximum
likelihood method, and detecting the signals transmitted from the transmitter.
17. A method for receiving signals in a MIMO (multiple input multiple output) system including a receiver for receiving signals from a transmitter
through multiple transmit channels wherein the transmitter includes multiple
transmit antennas and the receiver includes multiple receive antennas, the
method comprising: (a) receiving multipath signals through the multiple receive antennas,
and estimating respective transmit channel parameters that show states of
the multiple transmit channels;
(b) comparing the respective estimated transmit channel parameters,
and determining the transmit antenna corresponding to the transmit channel with the best state from among the multiple transmit antennas of the transmitter; (c) feeding the determined transmit antenna information back to the transmitter through a specific feedback path; (d) linearly combining the received signals, and outputting results; and (e) evaluating the received signals according to the maximum likelihood method, and detecting the signals transmitted from the transmitter.
18. A transmit power allocation method in a MIMO (multiple input multiple output) system including a transmitter and a receiver for receiving signals from the transmitter through multiple transmit channels wherein the transmitter includes multiple transmit antennas and the receiver includes multiple receive antennas, the method comprising: (a) the receiver receiving multipath signals through the multiple receive antennas, and estimating respective transmit channel parameters that show states of the multiple transmit channels; (b) the receiver comparing the respective estimated transmit channel parameters, determining the transmit antenna corresponding to the transmit channel with the best state from among the multiple transmit antennas of the transmitter, and feeding the determined transmit antenna information back to the transmitter through a specific feedback path; (c) the transmitter applying weights so that the maximum power may be applied to the signal supplied to the transmit antenna detected from the information fed back from the receiver in (b) from among the signals to be transmitted to the receiver; and (d) the transmitter transmitting the weight-applied signal to the receiver through the multiple transmit antennas.
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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7688979B2 (en) 2005-03-21 2010-03-30 Interdigital Technology Corporation MIMO air interface utilizing dirty paper coding
CN102017557A (en) * 2008-07-18 2011-04-13 上海贝尔股份有限公司 Methods and devices for making exchange processing for multiple sub channel signals in SC-FDMA system
CN102223213A (en) * 2010-04-16 2011-10-19 中国移动通信集团公司 Signal transmitting method and device
CN103427959A (en) * 2012-05-18 2013-12-04 英特尔移动通信有限责任公司 Transmission and detection in multiple-antenna transmission systems

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100704676B1 (en) * 2005-06-24 2007-04-06 한국전자통신연구원 Diversity Method and Base-Station for Controlling Power Allocation of Transmit Antenna in Mobile Communication System
KR100629490B1 (en) * 2005-08-18 2006-09-28 삼성전자주식회사 Transmitting apparatus of transmit diversity system and transmitting method thereof
KR100830229B1 (en) * 2006-07-07 2008-05-16 세종대학교산학협력단 Apparatus for efficient signal detection in multiple antenna system and method therof
KR100842620B1 (en) 2007-01-25 2008-06-30 삼성전자주식회사 Symbol error rate based power allocation scheme for orthogonal space time block codes in distributed wireless communication system
KR100866188B1 (en) 2007-02-22 2008-10-30 삼성전자주식회사 Symbol error rate approximation method for orthogonal space time block codes in distributed wireless communication system
KR101222130B1 (en) * 2008-12-19 2013-01-15 한국전자통신연구원 Multiple input multiple output radio communication system with pre-equalizer and its mehtod
KR101207000B1 (en) * 2011-01-26 2012-11-30 경희대학교 산학협력단 Apparatus and method for transmitting secrecy data on a number of transmission channels in a multi-channel communication system
KR101535643B1 (en) * 2012-03-08 2015-07-09 경희대학교 산학협력단 Method and apparatus for secrecy transmitting in wireless environment

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002082689A2 (en) * 2001-04-07 2002-10-17 Motorola, Inc. Feedback method for controlling a multiple-input, multiple-output communications channel
US20030043929A1 (en) * 2001-09-06 2003-03-06 Hemanth Sampath Transmit signal preprocessing based on transmit antennae correlations for muliple antennae systems
US20030148770A1 (en) * 2002-02-07 2003-08-07 Lucent Technologies Inc. Method and apparatus for closed loop transmit diversity in a wireless communications system

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002082689A2 (en) * 2001-04-07 2002-10-17 Motorola, Inc. Feedback method for controlling a multiple-input, multiple-output communications channel
US20030043929A1 (en) * 2001-09-06 2003-03-06 Hemanth Sampath Transmit signal preprocessing based on transmit antennae correlations for muliple antennae systems
US20030148770A1 (en) * 2002-02-07 2003-08-07 Lucent Technologies Inc. Method and apparatus for closed loop transmit diversity in a wireless communications system

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
ALAMOUTI S.M. ET AL.: "A simple transit diversity technique for wireless communications", IEEE JOURNAL OF SELECTED AREAS IN COMMUNICATIONS, vol. 16, no. 8, October 1998 (1998-10-01), pages 1451 - 1458 *

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7688979B2 (en) 2005-03-21 2010-03-30 Interdigital Technology Corporation MIMO air interface utilizing dirty paper coding
CN102017557A (en) * 2008-07-18 2011-04-13 上海贝尔股份有限公司 Methods and devices for making exchange processing for multiple sub channel signals in SC-FDMA system
CN102223213A (en) * 2010-04-16 2011-10-19 中国移动通信集团公司 Signal transmitting method and device
CN103427959A (en) * 2012-05-18 2013-12-04 英特尔移动通信有限责任公司 Transmission and detection in multiple-antenna transmission systems
CN103427959B (en) * 2012-05-18 2017-05-31 英特尔德国有限责任公司 Transmitting and detection in multi-aerial transmission system

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