TRANSMISSION/RECEPTION METHODS AND MODULES FOR A MULTIPLE-CARRIER MULTIPLE-ANTENNA SYSTEM USING TRAINING SEQUENCES
First Claim
1. A transmission method suitable for a system with Nt transmit antennas and Nr receive antennas, where Nt and Nr are at least 1, a transmit antenna being separated from a receive antenna by a transmission sub-channel, implemented by Nt multiple-carrier transmitters each including a multiplexing and modulation module using NFFT orthogonal functions (MX1 to MXNt) forming orthogonal symbols intended to be transmitted by the Nt transmit antennas TX1 to TXNt, the method including:
- a step of determining a basic training sequence ({tilde over (c)}(p)) from the position of Np pilot symbols in a time-frequency frame;
a step of determining replicas of the basic training sequence ({tilde over (c)}(p)) such that at least one replica is time offset from the basic sequence, with Ki≧
1 and at least one Ki≧
2, subject to the constraints that the extreme time offset between replicas must be less than the number Np of pilot carriers and that the minimum time offset between replicas of two training sequences is greater than or equal to the maximum spread of the delays of the sub-channels; and
a step of determining a training sequence for each transmit antenna TXi as the sum of the Ki replicas.
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Accused Products
Abstract
The present invention relates to a transmission method and device suitable for a system using Nt transmit antennas TXi and Nr receive antennas RXj. The symbols transmitted are inserted in a time-frequency frame that contains a training sequence. Each training sequence is constructed from replicas of a basic training sequence. At least one of the training sequences includes at least two replicas at least one of which is phase offset.
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Citations
20 Claims
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1. A transmission method suitable for a system with Nt transmit antennas and Nr receive antennas, where Nt and Nr are at least 1, a transmit antenna being separated from a receive antenna by a transmission sub-channel, implemented by Nt multiple-carrier transmitters each including a multiplexing and modulation module using NFFT orthogonal functions (MX1 to MXNt) forming orthogonal symbols intended to be transmitted by the Nt transmit antennas TX1 to TXNt, the method including:
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a step of determining a basic training sequence ({tilde over (c)}(p)) from the position of Np pilot symbols in a time-frequency frame; a step of determining replicas of the basic training sequence ({tilde over (c)}(p)) such that at least one replica is time offset from the basic sequence, with Ki≧
1 and at least one Ki≧
2, subject to the constraints that the extreme time offset between replicas must be less than the number Np of pilot carriers and that the minimum time offset between replicas of two training sequences is greater than or equal to the maximum spread of the delays of the sub-channels; anda step of determining a training sequence for each transmit antenna TXi as the sum of the Ki replicas. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 17, 18)
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9. A method for estimating transmission sub-channels in a multiple-antenna system using Nt transmit antennas (TX1 to TXNt), where Nt is at least 1, at least one receive antenna (RX1 to RXNt), and a time-frequency frame for each transmit antenna including Np pilot symbols (sp) forming a training sequence and data symbols of a payload signal, each of the Nt training sequences being the sum of Ki replicas of a basic training sequence ({tilde over (c)}(p)), either time offset or not, such that the values Ki are greater than or equal to 1 and at least one value Ki is greater than or equal to 2, being known to the receiver, and enabling the receiver to estimate an impulse response corresponding to the transmission channel separating a transmit antenna (TX1 to TXNt) from a receive antenna RXj concerned, the data symbols and the pilot symbols being frequency-modulated by a multiplexing and modulation module using NFFT orthogonal functions (MX1 to MXNt) to form orthogonal symbols that are transmitted by the transmit antennas in the form of a multiple-carrier signal using NFFT carriers, the method including:
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a step of computing a matrix A constructed in the form of blocks from the training sequences and from the Fourier matrix of dimensions NFFT×
NFFT, the number of blocks of which is equal to the product of the number of orthogonal symbols of the basic training sequence by the sum of the values Ki, a block being determined by the product of a diagonal matrix formed of the pilot symbols contained in an orthogonal symbol of the training sequence associated with the block multiplied by the Fourier matrix and including, for a receive antenna (RXj) concerned;a step of computing Ki estimates of at least one of the Nt impulse responses in the time domain by multiplying by the pseudo-inverse matrix of the matrix A Np pilot symbols extracted from a frequency-domain signal (Rj(n)) obtained after demodulation of a time-domain signal received by the receive antenna (RXj) concerned by means of a Fourier transform of size NFFT; a step of computing an average over the Ki estimates of the impulse response concerned. - View Dependent Claims (10, 11, 19, 20)
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12. A transmission module including a multiplexing and modulation module using NFFT orthogonal functions (MX1 to MXNt), suitable for a multiple-antenna system using Nt transmit antennas (TX1 to TXNt), Nr receive antennas, where Nt and Nr are at least 1, and a time-frequency frame for each transmit antenna including pilot symbols and data symbols of a payload signal, the data symbols and the pilot symbols being frequency-modulated by the multiplexing and modulation module (MX1 to MXNt) to form orthogonal symbols that are transmitted by a transmit antenna in the form of a multiple-carrier signal using NFFT carriers and using Np pilot carriers, the module including:
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a module for determining a basic training sequence ({tilde over (c)}(p)) from the position of Np pilot symbols in the time-frequency frame associated with a particular transmit antenna (TX1); a module for determining Kn, where replicas of the basic training sequence ({tilde over (c)}(p)) such that at least one replica is time offset from the basic sequence, with Ki≧
1 and at least one Ki≧
2, subject to the constraints that the extreme time difference between replicas is less than the number Np of pilot carriers and that the minimum time offset between replicas of two training sequences is greater than or equal to the maximum spread of the delays of the sub-channels connecting a transmit antenna to a receive antenna; anda module for determining a training sequence for each transmit antenna TXi as the sum of Ki replicas. - View Dependent Claims (13)
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14. A module for estimating transmission channels in a multiple-antenna system using Nt transmit antennas (TX1 to TXNt), where Nt is at least 1, at least one receive antenna (RX1 to RXNt), and a time-frequency frame for each transmit antenna including pilot symbols (sp) forming a training sequence and data symbols of a payload signal, the Nt training sequences being known to the receiver and enabling the receiver to estimate Nt impulse responses corresponding to the Nt transmission channels respectively separating one of the transmit antennas (TX1 to TXNt) from the receive antenna RXj concerned, the data symbols and the pilot symbols being frequency-modulated by a multiplexing and modulation module using NFFT orthogonal functions (MX1 to MXNt) to form orthogonal symbols that are transmitted by the transmit antennas in the form of a multiple-carrier signal using NFFT carriers with Np pilot carriers, characterized in that it includes means for computing a matrix A constructed in the form of blocks from the training sequences and from the Fourier matrix of dimensions NFFT×
- NFFT, the number of blocks of which is equal to the product of the number of orthogonal symbols of the basic training sequence by the sum of the values Ki, a block being determined by the product of a diagonal matrix formed of the pilot symbols contained in an orthogonal symbol of the training sequence associated with the block multiplied by the Fourier matrix, and, for a receive antenna (RXj) concerned;
means for computing Ki estimates of at least one of the Nt impulse responses in the time domain by multiplying Np pilot symbols extracted from a frequency-domain signal (Rj(n)) obtained after demodulation of a time-domain signal received by the receive antenna (RXj) concerned by means of an FFT of size NFFT by the pseudo-inverse matrix of the matrix A; and means for computing the average of the Ki estimates of the impulse response concerned. - View Dependent Claims (15, 16)
- NFFT, the number of blocks of which is equal to the product of the number of orthogonal symbols of the basic training sequence by the sum of the values Ki, a block being determined by the product of a diagonal matrix formed of the pilot symbols contained in an orthogonal symbol of the training sequence associated with the block multiplied by the Fourier matrix, and, for a receive antenna (RXj) concerned;
Specification