Long training sequence for MIMO WLAN systems
First Claim
1. A method for configuring a multiple input multiple output (MIMO) wireless communication, the method comprises:
- generating a plurality of preambles for a plurality of transmit antennas, wherein each of the plurality of preambles includes;
a carrier detection sequence at a legacy transmit rate;
a first channel sounding at the legacy transmit rate;
a signal field at the legacy transmit rate; and
a plurality of channel soundings at a MIMO transmit rate; and
simultaneously transmitting the plurality of preambles via the plurality of transmit antennas.
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Accused Products
Abstract
A method for configuring a multiple input multiple output (MIMO) wireless communication begins by generating a plurality of preambles for a plurality of transmit antennas. Each of the plurality of preambles includes a carrier detection sequence at a legacy transmit rate, a first channel sounding at the legacy transmit rate, a signal field at the legacy transmit rate, and Z−1 channel soundings at a MIMO transmit rate, where L corresponds to a number of channel soundings. The method continues by simultaneously transmitting the plurality of preambles via the plurality of transmit antennas.
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Citations
37 Claims
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1. A method for configuring a multiple input multiple output (MIMO) wireless communication, the method comprises:
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generating a plurality of preambles for a plurality of transmit antennas, wherein each of the plurality of preambles includes;
a carrier detection sequence at a legacy transmit rate;
a first channel sounding at the legacy transmit rate;
a signal field at the legacy transmit rate; and
a plurality of channel soundings at a MIMO transmit rate; and
simultaneously transmitting the plurality of preambles via the plurality of transmit antennas. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for generating a training symbol sequence for a multiple-output OFDM RFIC, the method comprising:
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generating M+1 OFDM symbols, where M is the number of RF outputs;
selecting the symbol transmitted at the first time instant on the second to Mth antennas to be the first symbol transmitted at the first time instance on the first antenna multiplied by a real scalar value multiplied by the first column of an M×
M unitary matrix;
selecting the symbol transmitted at the third to (M+1)th time instants on the first to Mth antennas to be the first symbol transmitted at the first time instance on the first antenna multiplied by the second to Mth columns of the same unitary matrix; and
selecting the symbol transmitted at the second time instant on the first to Mth antennas to be the first symbol transmitted at the first time instant on the first to Mth antennas. - View Dependent Claims (13, 14, 15, 16)
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17. A method for generating a training symbol sequence for a multiple-output OFDM RF transceiver, the method comprising:
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generating p*M OFDM symbols, where M is the number of RF outputs and p is an integer greater than 1;
selecting the symbol transmitted at the first time instant on the second to Mth antennas to be the first symbol transmitted at the first time instance on the first antenna multiplied by a real scalar value multiplied by the first column of an M×
M unitary matrix;
selecting the symbol transmitted at the second to Mth time instants on the first to Mth antennas to be the first symbol transmitted at the first time instance on the first antenna multiplied by the second to Mth columns of the same unitary matrix; and
selecting the symbols transmitted on each of the M antennas at the (M+1)th to the (p*M)th time instants to be (p-1) duplicate copies of the first M symbols transmitted on each of the M antennas.
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18. A method for computing an estimate of an N×
- M channel matrix for each of J subcarriers of a received OFDM transmission, N being the number of expected transmit antennas and M being the number of receive antennas, the method comprising;
removing the first K samples of each block of I+K, I>
=J samples;
applying a discrete Fourier transform to the remaining I samples of each block;
selecting from each output block of I samples the J subcarriers known to be excited at the transmitter with nonzero symbols;
forming an N×
L matrix of such outputs from each of the J subcarriers, each column of the matrix corresponding to the outputs on the jth subcarrier over L consecutive time instants from one receiver antenna and each row of the matrix corresponding to the outputs on the jth subcarrier over one time instant from all N receiver antennas;
post-multiplying this matrix by the Hermitian transpose of the M×
M unitary matrix used to multiply the known first symbol sent on the first transmit antenna; and
multiplying the resulting N×
M matrix by the complex conjugate of the known first symbol sent on the first transmit antenna.
- M channel matrix for each of J subcarriers of a received OFDM transmission, N being the number of expected transmit antennas and M being the number of receive antennas, the method comprising;
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19. A radio frequency integrated circuit (RFIC) transmitter comprises:
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baseband processing module operably coupled to generate a plurality of preambles; and
a radio frequency (RF) transmitter section operably coupled to transmit the plurality of preambles at a radio frequency via a plurality of antennas, wherein the baseband processing module generates the plurality of preambles to include;
a carrier detection sequence at a legacy transmit rate;
a first channel sounding at the legacy transmit rate;
a signal field at the legacy transmit rate; and
L−
1 channel soundings at a MIMO transmit rate, where L corresponds to a number of channel soundings. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
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30. A method for generating a signal field within a preamble of a wireless communication, the method comprises:
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indicating frame length of a multiple input multiple output (MIMO) wireless communication within the signal field such that legacy wireless communication devices can set collision avoidance for a duration of the MIMO wireless communication; and
setting a reserve bit within the signal field to indicate the MIMO wireless communication. - View Dependent Claims (31, 32, 33)
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34. A radio frequency integrated circuit (RFIC) transmitter comprises:
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baseband processing module operably coupled to generate a plurality of preambles; and
a radio frequency (RF) transmitter section operably coupled to transmit the plurality of preambles at a radio frequency via a plurality of antennas, wherein the baseband processing module generates a signal field within each the plurality of preambles;
indicating frame length of a multiple input multiple output (MIMO) wireless communication within the signal field such that legacy wireless communication devices can set collision avoidance for a duration of the MIMO wireless communication; and
setting a reserve bit within the signal field to indicate the MIMO wireless communication. - View Dependent Claims (35, 36, 37)
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Specification