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WO2006023832A2 - Method and apparatus for providing closed-loop transmit precoding - Google Patents

Method and apparatus for providing closed-loop transmit precoding Download PDF

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Publication number
WO2006023832A2
WO2006023832A2 PCT/US2005/029740 US2005029740W WO2006023832A2 WO 2006023832 A2 WO2006023832 A2 WO 2006023832A2 US 2005029740 W US2005029740 W US 2005029740W WO 2006023832 A2 WO2006023832 A2 WO 2006023832A2
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Prior art keywords
transmitter
receiver
precoding
codebook
sub
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PCT/US2005/029740
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French (fr)
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WO2006023832A3 (en
Inventor
Muhammad Z. Ikram
Eko N. Onggosanusi
Vasanthan Raghavan
Anand G. Dabak
Srinath Hosur
Badrinarayanan Varadarajan
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Texas Instruments Incorporated
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Priority to EP05789291.1A priority Critical patent/EP1784937A4/en
Publication of WO2006023832A2 publication Critical patent/WO2006023832A2/en
Publication of WO2006023832A3 publication Critical patent/WO2006023832A3/en

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Classifications

    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B7/00Radio transmission systems, i.e. using radiation field
    • H04B7/02Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/06Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
    • H04B7/0613Diversity 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
    • H04B7/0615Diversity 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
    • H04B7/0619Diversity 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
    • H04B7/0658Feedback reduction
    • H04B7/0663Feedback reduction using vector or matrix manipulations
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B7/00Radio transmission systems, i.e. using radiation field
    • H04B7/02Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/06Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
    • H04B7/0613Diversity 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
    • H04B7/0615Diversity 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
    • H04B7/0619Diversity 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
    • H04B7/0621Feedback content
    • H04B7/0634Antenna weights or vector/matrix coefficients
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B7/00Radio transmission systems, i.e. using radiation field
    • H04B7/02Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/06Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
    • H04B7/0613Diversity 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
    • H04B7/0615Diversity 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
    • H04B7/0619Diversity 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
    • H04B7/0636Feedback format
    • H04B7/0639Using selective indices, e.g. of a codebook, e.g. pre-distortion matrix index [PMI] or for beam selection
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00Baseband systems
    • H04L25/02Details ; arrangements for supplying electrical power along data transmission lines
    • H04L25/0202Channel estimation
    • H04L25/0204Channel estimation of multiple channels
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00Baseband systems
    • H04L25/02Details ; arrangements for supplying electrical power along data transmission lines
    • H04L25/0202Channel estimation
    • H04L25/024Channel estimation channel estimation algorithms
    • H04L25/0242Channel estimation channel estimation algorithms using matrix methods
    • H04L25/0248Eigen-space methods
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00Baseband systems
    • H04L25/02Details ; arrangements for supplying electrical power along data transmission lines
    • H04L25/03Shaping networks in transmitter or receiver, e.g. adaptive shaping networks
    • H04L25/03006Arrangements for removing intersymbol interference
    • H04L25/03343Arrangements at the transmitter end
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00Arrangements affording multiple use of the transmission path
    • H04L5/0001Arrangements for dividing the transmission path
    • H04L5/0014Three-dimensional division
    • H04L5/0023Time-frequency-space
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00Arrangements affording multiple use of the transmission path
    • H04L5/003Arrangements for allocating sub-channels of the transmission path
    • H04L5/0044Arrangements for allocating sub-channels of the transmission path allocation of payload
    • H04L5/0046Determination of how many bits are transmitted on different sub-channels
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00Arrangements affording multiple use of the transmission path
    • H04L5/003Arrangements for allocating sub-channels of the transmission path
    • H04L5/0058Allocation criteria
    • H04L5/006Quality of the received signal, e.g. BER, SNR, water filling
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00Baseband systems
    • H04L25/02Details ; arrangements for supplying electrical power along data transmission lines
    • H04L25/03Shaping networks in transmitter or receiver, e.g. adaptive shaping networks
    • H04L25/03006Arrangements for removing intersymbol interference
    • H04L2025/0335Arrangements for removing intersymbol interference characterised by the type of transmission
    • H04L2025/03375Passband transmission
    • H04L2025/03414Multicarrier
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00Baseband systems
    • H04L25/02Details ; arrangements for supplying electrical power along data transmission lines
    • H04L25/03Shaping networks in transmitter or receiver, e.g. adaptive shaping networks
    • H04L25/03006Arrangements for removing intersymbol interference
    • H04L2025/0335Arrangements for removing intersymbol interference characterised by the type of transmission
    • H04L2025/03426Arrangements for removing intersymbol interference characterised by the type of transmission transmission using multiple-input and multiple-output channels
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00Baseband systems
    • H04L25/02Details ; arrangements for supplying electrical power along data transmission lines
    • H04L25/03Shaping networks in transmitter or receiver, e.g. adaptive shaping networks
    • H04L25/03006Arrangements for removing intersymbol interference
    • H04L2025/03777Arrangements for removing intersymbol interference characterised by the signalling
    • H04L2025/03802Signalling on the reverse channel

Definitions

  • MIMO Multiple Input, Multiple Output
  • OFDM orthogonal frequency- division multiplexing
  • open-loop MIMO mode may be simple to implement, it suffers performance issues.
  • An alternative to open-loop mode is closed-loop processing, whereby channel-state information is referred from the receiver to the transmitter to precode the transmitted data for better reception. Closed-loop operation offers improved performance over open-loop operation, though not free of cost.
  • the transmission of channel-state information from the receiver to the transmitter involves significant overhead. Furthermore, the overhead cost of providing the necessary feedback is even higher in Orthogonal Frequency Division Multiplexing (OFDM)/Orthogonal Frequency Division Multiple Access (OFDMA) systems, where a different eigenvector is associated with each sub- carrier. It is desirable, therefore, to design a reduced-feedback closed-loop mode of operation with the performance similar to that obtained using the full channel-state information feedback.
  • OFDM Orthogonal Frequency Division Multiplexing
  • OFDMA Orthogonal Frequency Division Multiple Access
  • a codebook is defined that includes a set of precoding rotation matrices.
  • the receiver determines which precoding rotation matrix from the codebook should be used for each sub-carrier received.
  • the receiver sends an index to the transmitter, where the transmitter reconstructs the selected precoding rotation matrix using the index, and precedes the symbols to be transmitted using the precoding rotation matrix.
  • Some illustrative embodiments may include a method for providing closed-loop transmit precoding between a transmitter and a receiver, including the steps of defining a codebook that includes a set of precoding rotation matrices, and determining at the receiver a precoding rotation matrix from the codebook for each transmission sub-carrier that is received. Having determined a precoding rotation matrix for each transmission sub-carrier, the method comprises sending an index to the transmitter for each sub-carrier received, reconstructing the precoding rotation matrix selected by the receiver for each sub-carrier at the transmitter using the indices sent to the transmitter, and precoding information to be transmitted by the transmitter to the receiver using the reconstructed precoding rotation matrices.
  • illustrative embodiments may include a communication system including a receiver including a codebook that includes one or more precoding rotation matrices, and a transmitter transmitting information to the receiver using a sub-carrier, wherein the receiver determines a precoding rotation matrix from the codebook for the sub-carrier and sends an index to the transmitter indicating the precoding rotation matrix the transmitter should use for the sub-carrier.
  • Yet further illustrative embodiments may include a receiver including a plurality of antennas, a memory adapted to store a codebook comprising one or more precoding rotation matrices, and selection logic for choosing a precoding rotation matrix from among the one or more precoding rotation matrices based on information that has been received.
  • illustrative embodiments may include a receiver including means for storing one or more precoding rotation matrices, and means for selecting a precoding rotation matrix from among the one or more precoding rotation matrices based on information that has been received.
  • Still further illustrative embodiments may include a transmitter comprising a plurality of antennas, a memory adapted to store a codebook comprising one or more precoding rotation matrices, and an indexing logic adapted to select which precoding rotation matrix should be used based on an index received by the antenna.
  • FIG. 1 is a block diagram of a communication system in accordance with an embodiment of the invention.
  • FIG. 2 is a flowchart highlighting a closed-loop MIMO method in accordance with an embodiment of the invention.
  • FIG. 4 is a graph highlighting simulation results for a 2 X 2 open-loop MIMO versus a closed-loop MIMO using 16-QAM, rate 3 A, p - 0.7 in accordance with an embodiment of the invention.
  • FIG. 12 is a graph highlighting simulation results for a 2 X 2 open-loop MIMO versus a 4
  • FIG. 14 is a table highlighting the closed-loop performance for various MIMO modes in accordance with an embodiment of the invention.
  • FIG. 15 shows a diagram of a communication system in accordance with an embodiment of the invention.
  • a closed-loop MIMO transmission methodology where the transmitted symbols are precoded using a finite set of pre-defined unitary rotation matrices.
  • This set of matrices belong to a codebook which is known both to the receiver and to the transmitter.
  • the receiver Given the received data, the receiver determines the optimum rotation matrix for each OFDM/OFDMA sub-carrier that will result in the best performance.
  • the receiver transmits the index or indexes of the optimum rotation matrix(s) to the transmitter, where the matrix(s) is reconstructed and used to precode the transmitted symbols.
  • FIG. 1 there is shown a communication system 100 including a receiver, having Q antennas, and a transmitter, having P antennas, the Q-dimensional baseband received signal vector r , r 2 , ... , r Q 1 108 is represented as
  • H [h ⁇ , h 2 , ... , h p ] is the Q x P channel matrix
  • s [ ⁇ , S 2 , ... , s p f 106
  • the received signal can be processed by using either an optimal maximum-likelihood method or a sub-optimal method, such as zero-forcing or linear minimum mean squared error processing.
  • the vector s is represented by
  • V is the P x i? precoding rotation matrix 102, and R is the number of transmit data streams.
  • R is the number of transmit data streams.
  • the reason for introducing this notation is the added flexibility of treating closed-loop and open-loop options within the same framework. This notation also allows consideration of cases having transmit data streams less than or equal to the number of transmit antennas.
  • V is simply a Px P identity matrix.
  • the effective (rotated) channel matrix is, therefore, denoted by
  • the transmitted symbols can be precoded with the eigenvectors V of the matrix H ⁇ H , where (•)" denotes conjugate transposition.
  • the transmitted symbols can be separated at the receiver, thereby achieving capacity.
  • the transmission of complete channel state information from receiver to the transmitter is prohibitively expensive in terms of overhead.
  • an alternative to sending the complete channel state information is to define a codebook containing a finite set of N unitary rotation matrices.
  • the codebook is known to both the transmitter and the receiver.
  • the receiver Based on a metric that maximizes post-processed signal-to-noise ratio (SNR), the receiver determines a precoding rotation matrix from the codebook for each OFDM sub-carrier.
  • An index of this matrix is then sent to the transmitter via a feedback path (shown as 114 in Figure 1), where the same matrix is reconstructed and used to precode the transmitted symbols.
  • Block 110 also performs the channel estimation, symbol detection and the selection of the rotation matrix. For example, if the set has eight rotation matrices, then three bits per sub-carrier are sent back.
  • Block 110 may comprise selection logic for choosing a precoding rotation matrix from among the one or more precoding rotation matrices based on information that has been received, as well as logic adapted to other purposes, such as channel estimation and symbol detection.
  • the codebook is defined with a set of N rotation matrices denoted by V as follows:
  • N N 1 N 2 .
  • the index of the rotation matrix may be sent from the receiver to the transmitter only once per frame. This is assuming that the channel stays static over the frame duration.
  • V( ⁇ ,0 2 ⁇ 3 ) G(1,2,6' 1 )G(1,3 ⁇ 2 )G(2,3 ⁇ 3 ).
  • the Givens rotation angles are quantized to form a codebook of unitary matrices. For instance, for a 3 X 3 scenario, the quantized set of N rotation matrices is given by
  • N N 1 N 2 N 3 .
  • the feedback bits for this case equals 0 ⁇ 2 bits. If each rotation is quantized to four
  • the transmitter For 4 transmit antennas with 2 transmit streams, the transmitter is split into two 2-transmit antenna units. Each unit then transmits one data stream. A 2 X 1 precoding vector is associated with each data stream. The two resulting vectors are combined to form the precoding matrix V as follows:
  • the selection of the rotation matrix depends on the type of receiver employed to recover the transmitted source symbols.
  • an iterative minimum-mean squared error (IMMSE) receiver is used, which detects the transmitted symbols in the order of decreasing post-processed SNR; i.e., the most "reliable" symbols are detected first and removed from the received signal followed by estimating symbols of decreasing reliability.
  • the present invention can be used with other types of receivers.
  • SNR value is computed for the open-loop transmission.
  • the post- processed SNR for each unitary rotation matrix in the basis set is computed. Defining the rotated channel matrix as:
  • V ⁇ opt arg max (min (SNR;, . )) .
  • a codebook is defined which includes a set of unitary rotation matrices as previously discussed.
  • the codebook may be known to both the receiver and the transmitter.
  • a receiver determines a precoding rotation matrix from the codebook for each OFDM sub-carrier.
  • an index for each sub-carrier is sent by the receiver to the transmitter via a feedback path. While in 208, the rotation matrix is reconstructed from the index sent, and the reconstructed rotation matrix is used to precode the symbols that will be transmitted.
  • a communication device such as a laptop computer 502 that includes wireless interconnection capability in the form of a Wi-Fi circuit 506 communicates with an access point (also known as hot spot, etc.) 504.
  • an access point also known as hot spot, etc.
  • Wi-Fi communication block e.g., wireless communication card
  • the codebooks are stored in both the laptop computer 502 and the access point 504 or in another illustrative example in the access point controller which may be located remotely from the access point 504.
  • ( v N " N 2 ) J ( v 4 ' I) ; corresponds to a feedback of 2 bits per sub-carrier.
  • FIG. 3 there is shown a performance comparison between a 2 X 2 open loop MIMO 302 versus a closed-loop MIMO 304 in accordance with an embodiment of the present invention.
  • FIG. 4 there is shown a simulation showing the performance comparison of a 2 X 2 open-loop MIMO 402 versus a closed-loop MIMO in accordance with an embodiment of the invention.
  • FIG. 5 there is shown simulation results for a performance comparison between a 2 X 2 open-loop MIMO 502 versus a closed-loop MIMO 1 in accordance with an embodiment of the invention.
  • the feedback requirement is 6 bits per sub- carrier.
  • the graph shown in FIG. 9 highlights the performance comparison of a 4 X 4 open-loop MIMO design 902 versus a closed-loop MIMO design 904 in accordance with an embodiment of the invention.
  • FIGS. 11-13 The performance of 4x2 closed-loop MIMO against the 2x2 open-loop mode are compared in FIGS. 11-13.
  • FIG. 12 there is shown the performance comparison of a 2 X 2 open-loop MIMO 1202 versus a 4 X 2 closed-loop MIMO represented by graph line 1204 in accordance with an embodiment of the invention.
  • the closed-loop performance of different MIMO modes considered above is summarized in the table shown in FIG. 14. The table also lists the feedback bits required for each case.
  • the proposed MIMO closed-loop scheme of the present invention requires minimal feedback and results in improved gain over corresponding MIMO open-loop modes. As expected, larger gain was achieved for higher antenna correlation; also, the gain increased with the use of more transmit/receive antennas. Interpolation across frequency can be employed to further reduce the feedback requirement in the closed-loop methodology. However, interpolation works only when the OFDMA sub-carriers assigned to a user are arranged contiguously over the frequency band. Therefore, its application is limited only to certain frame structures.

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  • Engineering & Computer Science (AREA)
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  • Computer Networks & Wireless Communication (AREA)
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Abstract

A method for providing closed-loop transmit precoding between a transmitter and a receiver, includes defining a codebook that includes a set of unitary rotation matrices (202). The receiver determines which precoding rotation matrix from the codebook should be used for each sub-carrier that has been received (204). The receiver sends an index to the transmitter (206), where the transmitter reconstructs the precoding rotation matrix using the index, and precodes the symbols to be transmitted using the precoding rotation matrix (208). An apparatus that employs this closed-loop technique is also described.

Description

METHOD AND APPARATUS FOR PROVIDING CLOSED-LOOP TRANSMIT PRECODING This invention relates in general to the field of wireless communications, and more specifically, to a method and apparatus for providing closed loop transmit precoding. BACKGROUND Multiple Input, Multiple Output (MIMO) refers to the use of multiple transmitters and receivers (multiple antennas) on wireless devices for improved performance. When two transmitters and two or more receivers are used, two simultaneous data streams can be sent, thus doubling the data rate. Various wireless standards that are based on MIMO orthogonal frequency- division multiplexing (OFDM) technology use the open loop mode of operation. In the open-loop MIMO mode of operation, the transmitter assumes no knowledge of the communication channel. Although the open-loop MIMO mode may be simple to implement, it suffers performance issues. An alternative to open-loop mode is closed-loop processing, whereby channel-state information is referred from the receiver to the transmitter to precode the transmitted data for better reception. Closed-loop operation offers improved performance over open-loop operation, though not free of cost. The transmission of channel-state information from the receiver to the transmitter involves significant overhead. Furthermore, the overhead cost of providing the necessary feedback is even higher in Orthogonal Frequency Division Multiplexing (OFDM)/Orthogonal Frequency Division Multiple Access (OFDMA) systems, where a different eigenvector is associated with each sub- carrier. It is desirable, therefore, to design a reduced-feedback closed-loop mode of operation with the performance similar to that obtained using the full channel-state information feedback. SUMMARY
The problems noted above are solved in large part by a method and system to provide closed-loop transmit precoding between a transmitter and a receiver. A codebook is defined that includes a set of precoding rotation matrices. In the system and method of the present disclosure, the receiver determines which precoding rotation matrix from the codebook should be used for each sub-carrier received. The receiver sends an index to the transmitter, where the transmitter reconstructs the selected precoding rotation matrix using the index, and precedes the symbols to be transmitted using the precoding rotation matrix.
Some illustrative embodiments may include a method for providing closed-loop transmit precoding between a transmitter and a receiver, including the steps of defining a codebook that includes a set of precoding rotation matrices, and determining at the receiver a precoding rotation matrix from the codebook for each transmission sub-carrier that is received. Having determined a precoding rotation matrix for each transmission sub-carrier, the method comprises sending an index to the transmitter for each sub-carrier received, reconstructing the precoding rotation matrix selected by the receiver for each sub-carrier at the transmitter using the indices sent to the transmitter, and precoding information to be transmitted by the transmitter to the receiver using the reconstructed precoding rotation matrices.
Other illustrative embodiments may include a communication system including a receiver including a codebook that includes one or more precoding rotation matrices, and a transmitter transmitting information to the receiver using a sub-carrier, wherein the receiver determines a precoding rotation matrix from the codebook for the sub-carrier and sends an index to the transmitter indicating the precoding rotation matrix the transmitter should use for the sub-carrier.
Yet further illustrative embodiments may include a receiver including a plurality of antennas, a memory adapted to store a codebook comprising one or more precoding rotation matrices, and selection logic for choosing a precoding rotation matrix from among the one or more precoding rotation matrices based on information that has been received.
Other illustrative embodiments may include a receiver including means for storing one or more precoding rotation matrices, and means for selecting a precoding rotation matrix from among the one or more precoding rotation matrices based on information that has been received.
Still further illustrative embodiments may include a transmitter comprising a plurality of antennas, a memory adapted to store a codebook comprising one or more precoding rotation matrices, and an indexing logic adapted to select which precoding rotation matrix should be used based on an index received by the antenna. BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of a communication system in accordance with an embodiment of the invention.
FIG. 2 is a flowchart highlighting a closed-loop MIMO method in accordance with an embodiment of the invention.
FIG. 3 is a graph highlighting simulation results for a 2 X 2 open-loop MIMO versus a closed-loop MIMIO using QPSK, rate 3A, p = 0.7 in accordance with an embodiment of the invention. FIG. 4 is a graph highlighting simulation results for a 2 X 2 open-loop MIMO versus a closed-loop MIMO using 16-QAM, rate 3A, p - 0.7 in accordance with an embodiment of the invention.
FIG. 5 is a graph highlighting simulation results for a 2 X 2 open-loop MIMO versus a closed-loop MIMO using 64-QAM, rate 3A, p = 0.7 in accordance with an embodiment of the invention.
FIG. 6 is a graph highlighting simulation results for a 2 X 2 open-loop MIMO versus a closed-loop MIMO using QPSK, rate 3A, p = 0.2 in accordance with an embodiment of the invention. FIG. 7 is a graph highlighting simulation results for a 2 X 2 open-loop MIMO versus a closed-loop MIMO using 16-QAM, rate 3A, p = 0.2 in accordance with an embodiment of the invention.
FIG. 8 is a graph highlighting simulation results for a 2 X 2 open-loop MIMO versus a closed-loop MIMO using 16-QAM, rate 1A, p = 0.2 in accordance with an embodiment of the invention.
FIG. 9 is a graph highlighting simulation results for a 4 X 4 open-loop MIMO versus a closed-loop MIMO using QPSK, rate 3/4, p = 0.7 in accordance with an embodiment of the invention.
FIG. 10 is a graph highlighting simulation results for a 4 X 4 open-loop MIMO versus a closed-loop MIMO using 16-QAM, rate 3/4, p = 0.2 in accordance with an embodiment of the invention.
FIG. 11 is a graph highlighting simulation results for a 2 X 2 open-loop MIMO versus a 4 X 2 closed-loop MIMO using QPSK, rate 3/4, p = 0.7 in accordance with an embodiment of the invention. FIG. 12 is a graph highlighting simulation results for a 2 X 2 open-loop MIMO versus a 4
X 2 closed-loop MIMO using 16-QAM, rate 3/4, p = 0.7 in accordance with an embodiment of the invention.
FIG. 13 is a graph highlighting simulation results for a 2 X 2 open-loop MIMO versus a 4 X 2 closed-loop MIMO using 64-QAM, rate 3/4, p = 0.2 in accordance with an embodiment of the invention. FIG. 14 is a table highlighting the closed-loop performance for various MIMO modes in accordance with an embodiment of the invention.
FIG. 15 shows a diagram of a communication system in accordance with an embodiment of the invention. DETAILED DESCRIPTION
In one embodiment of the invention, a closed-loop MIMO transmission methodology, where the transmitted symbols are precoded using a finite set of pre-defined unitary rotation matrices, is described. This set of matrices belong to a codebook which is known both to the receiver and to the transmitter. Given the received data, the receiver determines the optimum rotation matrix for each OFDM/OFDMA sub-carrier that will result in the best performance. The receiver transmits the index or indexes of the optimum rotation matrix(s) to the transmitter, where the matrix(s) is reconstructed and used to precode the transmitted symbols. With a very few number of rotation matrices in the basic codebook, the amount of feedback involved is less than if the full set of channel coefficients are sent back from the receiver to the transmitter. Consider a MIMO OFDM setup with P transmit antennas and Q receive antennas as shown in FIG. 1. In FIG. 1 there is shown a communication system 100 including a receiver, having Q antennas, and a transmitter, having P antennas, the Q-dimensional baseband received signal vector r , r2 , ... , rQ 1 108 is represented as
Figure imgf000006_0001
where h(. = ϊhu,h ,...,hQi ~\ is a β-dimensional vector containing channel coefficients from /th transmitter to Q receivers, H = [h{ , h2 , ... , hp ] is the Q x P channel matrix, s = [η , S2 , ... , sp f 106
is the P-dimensional transmit signal vector, andw = [w, ,w2 ,..., wej is the g-dimensional vector of zero-mean noise with variance σ2. The received signal can be processed by using either an optimal maximum-likelihood method or a sub-optimal method, such as zero-forcing or linear minimum mean squared error processing. The vector s is represented by
S = Vd , where d = [d{,d2,...,dR]T 104 is the i?-dimensional vector of symbols to be transmitted,
V is the P x i? precoding rotation matrix 102, and R is the number of transmit data streams. The reason for introducing this notation is the added flexibility of treating closed-loop and open-loop options within the same framework. This notation also allows consideration of cases having transmit data streams less than or equal to the number of transmit antennas. For the open loop case, V is simply a Px P identity matrix. The effective (rotated) channel matrix is, therefore, denoted by
W = HV .
If perfect channel state information is available at the transmitter, then the transmitted symbols can be precoded with the eigenvectors V of the matrix H^H , where (•)" denotes conjugate transposition. In this case, the transmitted symbols can be separated at the receiver, thereby achieving capacity. The transmission of complete channel state information from receiver to the transmitter, however, is prohibitively expensive in terms of overhead.
In accordance with an embodiment of the invention, an alternative to sending the complete channel state information is to define a codebook containing a finite set of N unitary rotation matrices. The codebook is known to both the transmitter and the receiver. Based on a metric that maximizes post-processed signal-to-noise ratio (SNR), the receiver determines a precoding rotation matrix from the codebook for each OFDM sub-carrier. An index of this matrix is then sent to the transmitter via a feedback path (shown as 114 in Figure 1), where the same matrix is reconstructed and used to precode the transmitted symbols.
As shown in the communication system that includes a receiver and transmitter in FIG. 1, this operation requires only log2 N bits to be fed back along the feedback path 114 per OFDM sub- carrier (tone) by block 110. Block 110 also performs the channel estimation, symbol detection and the selection of the rotation matrix. For example, if the set has eight rotation matrices, then three bits per sub-carrier are sent back. Block 110 may comprise selection logic for choosing a precoding rotation matrix from among the one or more precoding rotation matrices based on information that has been received, as well as logic adapted to other purposes, such as channel estimation and symbol detection.
As an example, the 2x2 (two transmit/two receive antenna) scenario is reviewed first herein, followed by the generalized Px Q case, where P = Q > 2. The discussion herein will also show that 2x2 is a special case of the generalized P xg MIMO case, allowing treatment of all the MIMO cases using a single unified framework. The design of a 4x2 MIMO system with 2 transmit streams and 4 transmit antennas will also be discussed. For all the schemes, the design of the codebook and the impact of its size on the performance gain of closed-loop schemes in accordance with different embodiments of the invention will also be discussed. CASE OF: 2x2 MMO
For 2x 2 MIMO, the codebook is defined with a set of N rotation matrices denoted by V as follows:
V*1 cosfl. -e sin θ..
JV1B2+"! sin θ cosθ where,
φ = ^UL n - o,l,...,N2 -l
-Z V2 Tt Tl θn^ -^-,nλ = 0,l,...,N{ - \
and N = N1N2 .
Note that for each sub-carrier, the index of the rotation matrix may be sent from the receiver to the transmitter only once per frame. This is assuming that the channel stays static over the frame duration. CASE OF: P X Q (P = Q) MIMO
Considering the general ^ case, where ~ ~ . The real unitary rotation is p(p-\\h generated by applying a sequence of v '' Givens rotation to the channel matrix as follows: y(θ) = flf\ G{i,k,θ),
where the Givens rotation matrix is given as: G(i,k,θ) =
Figure imgf000009_0001
Col. i Col. k
with c =
Figure imgf000009_0002
= sin (θ) . Since G (i,k, θ) is orthogonal, the resulting rotation matrix V {θ) is unitary.
Note that each Givens rotation in the above product can be associated with a different
rotation angle. For example, for
Figure imgf000009_0003
s the product of three Givens rotations as follows:
V(^,02^3) = G(1,2,6'1)G(1,3^2)G(2,3^3).
As in the 2x2 case, the Givens rotation angles are quantized to form a codebook of unitary matrices. For instance, for a 3 X 3 scenario, the quantized set of N rotation matrices is given by
Figure imgf000009_0004
= G(h2,θ )G(l,3A2 )G(2,3.0j, where πn, θn]=^-,n^0,l}...,N,-l,
θ =≡^,n2=0,l,...,N2-l,
2N1
Figure imgf000009_0005
and N = N1N2N3.
The feedback bits for this case equals 0^2 bits. If each rotation is quantized to four
angles, then ^ " 2' 3/ v ' ' / ; resulting in a total of N - 64 unitary rotation matrices. This implies a feedback of 6 bits per OFDM sub-carrier. The selection of optimum rotation matrix is similar to the 2 x 2 Case and will be discussed further below.
From the above discussion, it can be appreciated that the Givens rotation approach to the generation of ^ unitary matrices can be extended to higher MIMO configurations. For
example, for a 4 X 4 system, the matrix V is a product of ^ )l ~ Givens rotations. Moreover, note that the 2 X 2 system is a special case of Givens rotation, where only one rotation is employed. CASE OF: 4 X 2 MIMO
For 4 transmit antennas with 2 transmit streams, the transmitter is split into two 2-transmit antenna units. Each unit then transmits one data stream. A 2 X 1 precoding vector is associated with each data stream. The two resulting vectors are combined to form the precoding matrix V as follows:
Figure imgf000010_0001
where
1 w», = j(πμ+2π,hlNλ ) W1 = O ^V1 - I ,
1 w«, = ej{π/4+2πn2/N2) H2 = O,...,N2 - I ,
andN = N!N2 .
SELECTION OF ROTATION MATRIX
The selection of the rotation matrix depends on the type of receiver employed to recover the transmitted source symbols. In one embodiment of the invention, an iterative minimum-mean squared error (IMMSE) receiver is used, which detects the transmitted symbols in the order of decreasing post-processed SNR; i.e., the most "reliable" symbols are detected first and removed from the received signal followed by estimating symbols of decreasing reliability. The present invention can be used with other types of receivers. The MMSE post-processed SNR of the P received symbol streams is given by: SNR1. K / = I,...,P,
Figure imgf000011_0001
where h; is the zth column of the channel matrix H and I is the P x P identity matrix. The above
SNR value is computed for the open-loop transmission.
In order to pick the best rotation matrix for each tone in the OFDM symbol, the post- processed SNR for each unitary rotation matrix in the basis set is computed. Defining the rotated channel matrix as:
H;, = HVn, « = 0,1,...,N- I, then the post-processed SNR for each case is given by:
sNR;, 0,...,N-l.
Figure imgf000011_0002
Of the P received streams, the smallest SNR value is selected and maximized over all possibilities of the rotation matrices. Mathematically, the selection of rotation matrix can be stated as:
Vπ opt = arg max (min (SNR;, . )) .
The above operation guarantees the maximization of the minimum post-processed SNR
P over all the possible choices. Note that for IMMSE processing, the interference term^h^.h^
>1 j≠i deflates each time a signal is estimated and subtracted from the received signal.
Referring now to FIG. 2, there is shown a flowchart highlighting a method for providing closed-loop transmit precoding in accordance with an embodiment of the invention. In 202, a codebook is defined which includes a set of unitary rotation matrices as previously discussed. The codebook may be known to both the receiver and the transmitter. In 204, a receiver determines a precoding rotation matrix from the codebook for each OFDM sub-carrier. In 206, an index for each sub-carrier is sent by the receiver to the transmitter via a feedback path. While in 208, the rotation matrix is reconstructed from the index sent, and the reconstructed rotation matrix is used to precode the symbols that will be transmitted. In FIG. 15, there is shown an illustrative example of a communication system 500 employing the closed-loop scheme of the present invention. A communication device such as a laptop computer 502 that includes wireless interconnection capability in the form of a Wi-Fi circuit 506 communicates with an access point (also known as hot spot, etc.) 504. Although shown using a Wi-Fi communication block (e.g., wireless communication card) other communication standards can also be used in association with the closed-loop technique of the present invention. In one embodiment, the codebooks are stored in both the laptop computer 502 and the access point 504 or in another illustrative example in the access point controller which may be located remotely from the access point 504. SIMULATION RESULTS
To verify the potential of the proposed closed-loop method in accordance with an embodiment of the invention, numerical simulations for various baseband MIMO OFDM system configurations employing an IMMSE receiver were performed. For the simulations, 768 data tones in the OFDM symbol were considered, which employed 1024-point inverse fast Fourier transform/ fast Fourier transform (IFFT/FFT) at the transmitter/receiver. The frame duration was set to 5msec and a delay of 2 frames was used for the feedback of channel-state information. Convolutional coding was used for forward-error correction and employed an iterative minimum mean squared error (IMMSE) receiver for decoding of transmitted symbols.
In the simulations, the International Telecommunication Union (ITU) outdoor-to-indoor pedestrian (OIP-B) channels were used with vehicular speeds of 3 km/hr. Transmit antenna correlation of P = or ^ = were used in the experiments. For all the simulations performed, ideal channel knowledge was assumed at the receiver. The frame-error rate (FER) results are discussed below for each MIMO configuration, where the open-loop performance is compared against the closed-loop performance to gauge the gain. CASE OF: 2 X 2 SIMULATIONS
Various simulation results for 2x2 MIMO using different modulation modes are shown in
FIGS. 3-8. Note that ( vN " N 2 )J = ( v4 ' I) ; corresponds to a feedback of 2 bits per sub-carrier. In FIG.
3, there is shown a performance comparison between a 2 X 2 open loop MIMO 302 versus a closed-loop MIMO 304 in accordance with an embodiment of the present invention. The modulation used was Quadrature Phase Shift Keying (QPSK), rate % and a transmit antenna correlation, P = 0.7. In FIG. 4 there is shown a simulation showing the performance comparison of a 2 X 2 open-loop MIMO 402 versus a closed-loop MIMO in accordance with an embodiment of the invention. The modulation used was 16 Quadrature Amplitude Modulation (16-QAM), rate 3A, P = 0.7. Referring now to FIG. 5, there is shown simulation results for a performance comparison between a 2 X 2 open-loop MIMO 502 versus a closed-loop MIMO1 in accordance with an embodiment of the invention. The simulation in FIG. 5 used 64-QAM, rate 3A and P = 0.7. In FIG. 6, there is shown another simulation highlighting the performance comparison between a 2 X 2 open-loop MIMO 602 against a closed-loop MIMO 604 in accordance with an embodiment of the invention. Modulation used was QPSK, rate 3A and P = 0.2. In FIG. 7 there is shown a simulation comparing the performance of a 2 X 2 open-loop MIMO 702 versus a closed-loop MIMO 704 using 16-QAM, rate of 3A and P = 0.2. In FIG. 8, there is another simulation result highlighting a 2 X 2 open-loop MIMO 802 versus a closed-loop MIMO 804 using 16-QAM, rate V2 and P = 0.2. CASE OF: 4 X 4 SIMULATION RESULTS
For the 4 X 4 simulation results depicted below, the feedback requirement is 6 bits per sub- carrier. The graph shown in FIG. 9 highlights the performance comparison of a 4 X 4 open-loop MIMO design 902 versus a closed-loop MIMO design 904 in accordance with an embodiment of the invention. The simulation was performed using QPSK, rate 3A and P = 0.7. In FIG. 10, simulation results comparing a 4 X 4 open-loop MIMO design 1002 versus a closed-loop MIMO 1004 in accordance with an embodiment of the invention are shown. In this simulation 16-QAM, rate 3A and a P = 0.2 were used. CASE OF: 4 X 2 SIMULATION RESULTS
The performance of 4x2 closed-loop MIMO against the 2x2 open-loop mode are compared in FIGS. 11-13. The parameter SCt(N15N2) = (2,2) implies a feedback of 2 bits per sub- carrier, whereas (N15N2) = (4,4) corresponds to 4 bits feedback per sub-carrier. In FIG. 11, the performance of a 2 X 2 open-loop MIMO 1102 is compared to a 4 X2 closed-loop MIMO where graph line 1104 represents a design where N1 = 2 and N2 = 2, and graph line 1106 is a closed-loop design were N1 = 4 and N2 = 4. The simulation was performed using QPSK, rate 3A and p = 0.7. In FIG. 12 there is shown the performance comparison of a 2 X 2 open-loop MIMO 1202 versus a 4 X 2 closed-loop MIMO represented by graph line 1204 in accordance with an embodiment of the invention. The closed-loop parameters were set to N1 = 2 and N2 = 2. In this simulation, QAM modulation was used with a rate 3A and p = 0.7. Finally, in FIG. 13, a simulation of the performance comparison of a 2 X 2 open-loop MIMO 1302 versus a 4 X 2 closed-loop MIMO 1304 using QAM modulation, rate 3A and p = 0.2 is shown. The closed-loop MIMO had an Ni = 2 and an N2 = 2. The closed-loop performance of different MIMO modes considered above is summarized in the table shown in FIG. 14. The table also lists the feedback bits required for each case.
The proposed MIMO closed-loop scheme of the present invention requires minimal feedback and results in improved gain over corresponding MIMO open-loop modes. As expected, larger gain was achieved for higher antenna correlation; also, the gain increased with the use of more transmit/receive antennas. Interpolation across frequency can be employed to further reduce the feedback requirement in the closed-loop methodology. However, interpolation works only when the OFDMA sub-carriers assigned to a user are arranged contiguously over the frequency band. Therefore, its application is limited only to certain frame structures.
While the preferred embodiments of the invention have been illustrated and described, it will be clear that the invention is not so limited. Numerous modifications, changes, variations, substitutions and equivalents will occur to those skilled in the art without departing from the scope of the present invention as encompassed by the appended claims.

Claims

1. A method for providing closed-loop transmit precoding between a transmitter and a receiver, comprising: defining a codebook that includes a set of precoding rotation matrices; determining at the receiver a precoding rotation matrix from the codebook for each transmission sub-carrier that is received; sending an index to the transmitter for each sub-carrier received; reconstructing the precoding rotation matrix selected by the receiver for each sub- carrier at the transmitter using the indices sent to the transmitter; and precoding information to be transmitted by the transmitter to the receiver using the reconstructed precoding rotation matrices.
2. A method as defined in claim 1, wherein sending the index comprises sending an index having a length of log2N bits, where N is the number of precoding rotation matrices found in the codebook.
3. A method as defined in claim 1 or 2, wherein the transmitter and receiver form a 2 X 2 MIMO system and the codebook includes a set of N precoding rotation matrices denoted by V, where: em÷ cos θ. -em> sin θ..
V, sin θ. cos θ..
φn2 = ~^,n2 = O,l,...,N2 -l where, 2 and
TC Yl θ „, = — 2^- l ,n, i = 0,1,...,N1 i -I
N = N1N2.
4. A communication system comprising: a receiver including a codebook that includes one or more precoding rotation matrices; and a transmitter transmitting information to the receiver using a sub-carrier; wherein the receiver determines a precoding rotation matrix from the codebook for the sub-carrier and sends an index to the transmitter indicating the precoding rotation matrix the transmitter should use for the sub-carrier.
1
5. The communication system as defined in claim 4, wherein the receiver sends an index to the transmitter for each sub-carrier received from the transmitter; and wherein the index has a length of log2N bits, where N is the number of precoding rotation matrices found in the codebook..
6. A receiver, comprising: a plurality of antennas; a memory adapted to store a codebook comprising one or more precoding rotation matrices; and selection logic for choosing a precoding rotation matrix from among the one or more precoding rotation matrices based on information that has been received.
7.. The receiver as defined in claim 6, wherein the antennas are further adapted to send an index informing a transmitter the precoding rotation matrix selected by the receiver to be used; and wherein the receiver sends the transmitter an index for each sub-carrier used by the transmitter.
8. A transmitter, comprising: a plurality of antennas; a memory adapted to store a codebook comprising one or more precoding rotation matrices; and an indexing logic adapted to select which precoding rotation matrix should be used based on an index received by the antenna.
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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011080774A1 (en) 2009-12-30 2011-07-07 Telecom Italia S.P.A Method for selecting a precodlng matrix in a "multiple input multiple output" ("mimo") system
US8171372B2 (en) 2007-04-30 2012-05-01 Interdigital Technology Corporation Feedback signaling error detection and checking in MIMO wireless communication systems
CN101217304B (en) * 2008-01-10 2013-01-30 北京邮电大学 A multi-input and multi-output recoding processing method of multi-subchannel
CN101232317B (en) * 2007-01-09 2013-03-20 美国博通公司 Method and system for a delta quantizer to process communication signals
CN101232475B (en) * 2007-01-09 2013-07-03 美国博通公司 Method and system for processing communication signal in MIMO precoder

Families Citing this family (73)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ATE452328T1 (en) * 2004-01-07 2010-01-15 Nxp Bv AMR SENSOR ELEMENT FOR ANGLE MEASUREMENTS
US8023589B2 (en) * 2004-08-09 2011-09-20 Texas Instruments Incorporated Wireless MIMO transmitter with antenna and tone precoding blocks
US7492829B2 (en) * 2004-09-10 2009-02-17 Intel Corporation Closed loop feedback in MIMO systems
US7539253B2 (en) * 2004-09-10 2009-05-26 Intel Corporation Interpolation in channel state feedback
KR20060038812A (en) * 2004-11-01 2006-05-04 엘지전자 주식회사 Method for transmitting precoding matrix and transmitting signal using the precoding matrix
US7239659B2 (en) * 2004-11-04 2007-07-03 Motorola, Inc. Method and apparatus for channel feedback
US7873016B2 (en) * 2005-11-07 2011-01-18 Broadcom Corporation Method and system for utilizing tone grouping with givens rotations to reduce overhead associated with explicit feedback information
US8180314B2 (en) * 2006-03-08 2012-05-15 Broadcom Corporation Method and system for utilizing givens rotation to reduce feedback information overhead
US8737494B2 (en) * 2006-01-09 2014-05-27 Broadcom Corporation Method and system for quantization for a general beamforming matrix in feedback information
KR20070108304A (en) * 2005-10-31 2007-11-09 삼성전자주식회사 Method and apparatus for transmitting/receiving of channel quality imformation in multi antenna system
US7917176B2 (en) * 2006-02-14 2011-03-29 Nec Laboratories America, Inc. Structured codebook and successive beamforming for multiple-antenna systems
US8233552B2 (en) * 2005-11-07 2012-07-31 Broadcom Corporation Method and system for utilizing givens rotation expressions for asymmetric beamforming matrices in explicit feedback information
US7602745B2 (en) * 2005-12-05 2009-10-13 Intel Corporation Multiple input, multiple output wireless communication system, associated methods and data structures
US10873375B2 (en) * 2006-03-20 2020-12-22 Texas Instruments Incorporated Pre-coder selection based on resource block grouping
KR20070113967A (en) * 2006-05-26 2007-11-29 엘지전자 주식회사 Phase shift based precoding method and tranceiver supporting the same
US8116391B2 (en) 2006-05-26 2012-02-14 Wi-Lan Inc. Quantization of channel state information in multiple antenna systems
TWI343200B (en) * 2006-05-26 2011-06-01 Lg Electronics Inc Method and apparatus for signal generation using phase-shift based pre-coding
KR101295576B1 (en) * 2006-06-22 2013-08-09 엘지전자 주식회사 data transfer method using phase-shift based precoding and transmitter implementing the same
US8396158B2 (en) * 2006-07-14 2013-03-12 Nokia Corporation Data processing method, data transmission method, data reception method, apparatus, codebook, computer program product, computer program distribution medium
US20080037669A1 (en) * 2006-08-11 2008-02-14 Interdigital Technology Corporation Wireless communication method and system for indexing codebook and codeword feedback
KR101249359B1 (en) 2006-08-18 2013-04-01 삼성전자주식회사 Method and apparatus for transmitting/receiving channel quality information in an orthogonal frequency division multiplexing system supporting a multi-input multi-output
KR20080022033A (en) * 2006-09-05 2008-03-10 엘지전자 주식회사 Method for feed back information concerning pre-coding and method for pre-coding
US7983352B2 (en) * 2006-09-15 2011-07-19 Futurewei Technologies, Inc. Power allocation in a MIMO system without channel state information feedback
KR20080026019A (en) * 2006-09-19 2008-03-24 엘지전자 주식회사 Phase shift based precoding method and tranceiver supporting the same
KR20080026010A (en) * 2006-09-19 2008-03-24 엘지전자 주식회사 Data transmitting method using phase-shift based precoding and tranceiver implementing the same
FR2906659B1 (en) * 2006-10-03 2008-12-19 Commissariat Energie Atomique SPATIO-TEMPORAL ENCODING METHOD FOR MULTI-ANTENNA COMMUNICATION SYSTEM OF IMPULSIVE UWB TYPE
CN101166052B (en) 2006-10-19 2012-05-23 株式会社Ntt都科摩 Precoding method of multi-input multi-output system and equipment using same
US20080094281A1 (en) * 2006-10-24 2008-04-24 Nokia Corporation Advanced codebook for multi-antenna transmission systems
WO2008050193A2 (en) * 2006-10-24 2008-05-02 Nokia Corporation Advanced codebook for multi-antenna transmission systems
US7961640B2 (en) * 2006-10-26 2011-06-14 Qualcomm Incorporated Method and apparatus for codebook exchange in a multiple access wireless communication system
TWI508478B (en) * 2006-10-30 2015-11-11 Interdigital Tech Corp Wireless transmit/receive unit and method for processing feedback implemented in wireless transmit/receive unit
US8204142B2 (en) * 2007-01-29 2012-06-19 Samsung Electronics Co., Ltd Precoder and precoding method in a multi-antenna system
WO2008097629A2 (en) * 2007-02-06 2008-08-14 Interdigital Technology Corporation Method and apparatus for multiple-input multiple-output feedback generation
KR20080073624A (en) 2007-02-06 2008-08-11 삼성전자주식회사 Codebook generating method for multi-polarized mimo system and device of enabling the method
US20080192852A1 (en) 2007-02-12 2008-08-14 Mark Kent Method and system for an alternating channel delta quantizer for 2x2 mimo pre-coders with finite rate channel state information feedback
US8687715B2 (en) * 2007-02-12 2014-04-01 Broadcom Corporation Method and system for rate reduction pre-coding matrices
US8090049B2 (en) 2007-02-12 2012-01-03 Broadcom Corporation Method and system for an alternating delta quantizer for limited feedback MIMO pre-coders
US8090048B2 (en) * 2007-02-12 2012-01-03 Broadcom Corporation Method and system for an alternating channel delta quantizer for MIMO pre-coders with finite rate channel state information feedback
KR20080076683A (en) * 2007-02-14 2008-08-20 엘지전자 주식회사 Phase shift based precoding method and tranceiver supporting the same
US8861356B2 (en) * 2007-03-13 2014-10-14 Ntt Docomo, Inc. Method and apparatus for prioritized information delivery with network coding over time-varying network topologies
US7995457B2 (en) * 2007-04-16 2011-08-09 Broadcom Corporation Method and system for SFBC/STBC transmission of orthogonally coded signals with angle feedback in a diversity transmission system
US8179775B2 (en) * 2007-08-14 2012-05-15 Texas Instruments Incorporated Precoding matrix feedback processes, circuits and systems
US8254507B2 (en) * 2007-06-18 2012-08-28 Broadcom Corporation Method and system for SFBC/STBC in a communication diversity system using angle feedback
WO2008157620A2 (en) * 2007-06-19 2008-12-24 Interdigital Technology Corporation Constant modulus mimo precoding for constraining transmit antenna power for differential feedback
KR101340108B1 (en) * 2007-07-19 2013-12-10 인터디지탈 테크날러지 코포레이션 Wireless communication method and apparatus for encoding and decoding beamforming vectors
GB2452319B (en) * 2007-08-31 2009-09-30 Toshiba Res Europ Ltd Wireless communications apparatus
US8036282B2 (en) 2007-09-07 2011-10-11 Wi-Lan Inc. Multi-tiered quantization of channel state information in multiple antenna systems
US8009778B2 (en) 2007-09-07 2011-08-30 Tr Technologies Inc. Quantized channel state information prediction in multiple antenna systems
KR20090030200A (en) * 2007-09-19 2009-03-24 엘지전자 주식회사 Data transmitting and receiving method using phase shift based precoding and transceiver supporting the same
US20090075686A1 (en) * 2007-09-19 2009-03-19 Gomadam Krishna S Method and apparatus for wideband transmission based on multi-user mimo and two-way training
US20110059703A1 (en) * 2007-09-28 2011-03-10 Nokia Corporation User equipment-initiated precoding subset restriction for communication systems
CN101471907A (en) * 2007-12-28 2009-07-01 三星电子株式会社 Pre-coding method of multi-input multi-output system and device using the method
ES2624635T3 (en) * 2008-01-14 2017-07-17 Telefonaktiebolaget Lm Ericsson (Publ) Open loop precoder cycles in MIMO communications
US8234546B2 (en) 2008-04-21 2012-07-31 Wi-Lan, Inc. Mitigation of transmission errors of quantized channel state information feedback in multi antenna systems
US8565329B2 (en) * 2008-06-03 2013-10-22 Ntt Docomo, Inc. Soft output M-algorithm receiver structures with generalized survivor selection criteria for MIMO systems
KR101056614B1 (en) 2008-07-30 2011-08-11 엘지전자 주식회사 Data transmission method in multi-antenna system
KR20100013251A (en) * 2008-07-30 2010-02-09 엘지전자 주식회사 Method for transmitting data in multiple antenna system
KR101027237B1 (en) * 2008-07-30 2011-04-06 엘지전자 주식회사 Method for transmitting data in multiple antenna system
GB2467303B (en) * 2008-08-07 2012-07-11 Icera Inc Feedback in a wireless communication system
US8705484B2 (en) * 2008-08-15 2014-04-22 Ntt Docomo, Inc. Method for varying transmit power patterns in a multi-cell environment
US8542640B2 (en) * 2008-08-28 2013-09-24 Ntt Docomo, Inc. Inter-cell approach to operating wireless beam-forming and user selection/scheduling in multi-cell environments based on limited signaling between patterns of subsets of cells
US9112562B2 (en) * 2008-09-02 2015-08-18 Intel Corporation Techniques utilizing adaptive codebooks for beamforming in wireless networks
US8855221B2 (en) * 2008-09-15 2014-10-07 Ntt Docomo, Inc. Method and apparatus for iterative receiver structures for OFDM/MIMO systems with bit interleaved coded modulation
US9048977B2 (en) * 2009-05-05 2015-06-02 Ntt Docomo, Inc. Receiver terminal driven joint encoder and decoder mode adaptation for SU-MIMO systems
CN102035626B (en) * 2009-09-30 2013-06-12 华为技术有限公司 Method and device for acquiring pre-coding matrix index
US8295335B2 (en) 2009-12-31 2012-10-23 Intel Corporation Techniques to control uplink power
PL2533524T3 (en) * 2010-02-03 2016-04-29 Lg Electronics Inc Apparatus and method for transmitting broadcast signals
WO2011096738A2 (en) * 2010-02-04 2011-08-11 엘지전자 주식회사 Broadcast signal transmitter and receiver, and broadcast signal transmitting and receiving method
DK2533526T3 (en) * 2010-02-04 2016-02-08 Lg Electronics Inc Transmission signal receiver and reception method
PL2533529T3 (en) * 2010-02-04 2016-02-29 Lg Electronics Inc Broadcast signal transmitter and transmitting method
GB2514111A (en) * 2013-05-13 2014-11-19 British Broadcasting Corp Transmission techniques
CN103368701B (en) * 2013-07-12 2016-06-08 中国科学技术大学 A kind of physical layer multicast multi-stream data transmission method based on Givens rotation
US10924166B2 (en) * 2016-10-25 2021-02-16 Nxp Usa, Inc. Complexity reduction for transmitter precoding

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5268938A (en) * 1992-01-21 1993-12-07 International Business Machines Corporation Redundancy scheme for Fourier transform coding on peak limited channels
US6252544B1 (en) * 1998-01-27 2001-06-26 Steven M. Hoffberg Mobile communication device
US8290098B2 (en) * 2001-03-30 2012-10-16 Texas Instruments Incorporated Closed loop multiple transmit, multiple receive antenna wireless communication system
KR100896682B1 (en) * 2002-04-09 2009-05-14 삼성전자주식회사 Mobile communication apparatus and method having transmitting/receiving multiantenna
US7242663B2 (en) * 2002-06-19 2007-07-10 George L. Yang Multi-channel spread spectrum communications system
US20030235146A1 (en) * 2002-06-21 2003-12-25 Yunnan Wu Bezout precoder for transmitter in MIMO communications network
ATE421809T1 (en) * 2002-08-22 2009-02-15 Imec Inter Uni Micro Electr MULTI-USER MIMO TRANSMISSION METHOD AND CORRESPONDING DEVICES
KR100918717B1 (en) * 2003-04-21 2009-09-24 삼성전자주식회사 Sequence estimating method and device in mimo ofdm communication system
US7242724B2 (en) * 2003-07-16 2007-07-10 Lucent Technologies Inc. Method and apparatus for transmitting signals in a multi-antenna mobile communications system that compensates for channel variations
US20050286663A1 (en) * 2004-06-23 2005-12-29 Intel Corporation Compact feedback for closed loop MIMO systems

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of EP1784937A4 *

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
TWI474687B (en) * 2007-01-09 2015-02-21 Broadcom Corp Method and system for a delta quantizer for mimo pre-coders with finite rate channel state information feedback
CN101232317B (en) * 2007-01-09 2013-03-20 美国博通公司 Method and system for a delta quantizer to process communication signals
CN101232475B (en) * 2007-01-09 2013-07-03 美国博通公司 Method and system for processing communication signal in MIMO precoder
US9459954B2 (en) 2007-04-30 2016-10-04 Interdigital Technology Corporation Feedback signaling error detection and checking in MIMO wireless communication systems
US8572461B2 (en) 2007-04-30 2013-10-29 Interdigital Technology Corporation Feedback signaling error detection and checking in MIMO wireless communication systems
US8171372B2 (en) 2007-04-30 2012-05-01 Interdigital Technology Corporation Feedback signaling error detection and checking in MIMO wireless communication systems
US8707129B2 (en) 2007-04-30 2014-04-22 Interdigital Technology Corporation Feedback signaling error detection and checking in MIMO wireless communication systems
US9048998B2 (en) 2007-04-30 2015-06-02 Interdigital Technology Corporation Feedback signaling error detection and checking in MIMO wireless communication systems
US10037243B2 (en) 2007-04-30 2018-07-31 Interdigital Technology Corporation Feedback signaling error detection and checking in MIMO wireless communication systems
US10318374B2 (en) 2007-04-30 2019-06-11 Interdigital Technology Corporation Feedback signaling error detection and checking in MIMO wireless communication systems
US10970162B2 (en) 2007-04-30 2021-04-06 Interdigital Technology Corporation Feedback signaling error detection and checking in MIMO wireless communication systems
US11687401B2 (en) 2007-04-30 2023-06-27 Interdigital Technology Corporation Feedback signaling error detection and checking in MIMO wireless communication systems
US12079074B2 (en) 2007-04-30 2024-09-03 Interdigital Technology Corporation Error detection and checking in wireless communication systems
CN101217304B (en) * 2008-01-10 2013-01-30 北京邮电大学 A multi-input and multi-output recoding processing method of multi-subchannel
WO2011080774A1 (en) 2009-12-30 2011-07-07 Telecom Italia S.P.A Method for selecting a precodlng matrix in a "multiple input multiple output" ("mimo") system
US8817904B2 (en) 2009-12-30 2014-08-26 Telecom Italia S.P.A. Method for selecting a precoding matrix in a multiple input multiple output (“MIMO”) system

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US20060039489A1 (en) 2006-02-23

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