Transmit diversity and spatial spreading for an OFDM-based multi-antenna communication system
First Claim
1. A method of transmitting data from a transmitting entity to a receiving entity in a wireless multi-antenna communication system utilizing orthogonal frequency division multiplexing (OFDM), comprising:
- processing a data packet to obtain a block of data symbols;
demultiplexing pilot symbols and the block of data symbols onto a plurality of subbands to obtain, for the data packet, a plurality of sequences of pilot and data symbols for the plurality of subbands; and
performing spatial processing on the sequence of pilot and data symbols for each subband with at least one steering vector selected for the subband, the spatial processing randomizing a plurality of effective single-input single-output (SISO) channels observed by the plurality of sequences of pilot and data symbols sent on the plurality of subbands.
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Accused Products
Abstract
A multi-antenna transmitting entity transmits data to a single- or multi-antenna receiving entity using (1) a steered mode to direct the data transmission toward the receiving entity or (2) a pseudo-random transmit steering (PRTS) mode to randomize the effective channels observed by the data transmission across the subbands. The PRTS mode may be used to achieve transmit diversity or spatial spreading. For transmit diversity, the transmitting entity uses different pseudo-random steering vectors across the subbands but the same steering vector across a packet for each subband. The receiving entity does not need to have knowledge of the pseudo-random steering vectors or perform any special processing. For spatial spreading, the transmitting entity uses different pseudo-random steering vectors across the subbands and different steering vectors across the packet for each subband. Only the transmitting and receiving entities know the steering vectors used for data transmission.
214 Citations
64 Claims
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1. A method of transmitting data from a transmitting entity to a receiving entity in a wireless multi-antenna communication system utilizing orthogonal frequency division multiplexing (OFDM), comprising:
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processing a data packet to obtain a block of data symbols;
demultiplexing pilot symbols and the block of data symbols onto a plurality of subbands to obtain, for the data packet, a plurality of sequences of pilot and data symbols for the plurality of subbands; and
performing spatial processing on the sequence of pilot and data symbols for each subband with at least one steering vector selected for the subband, the spatial processing randomizing a plurality of effective single-input single-output (SISO) channels observed by the plurality of sequences of pilot and data symbols sent on the plurality of subbands. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. An apparatus in a wireless multi-antenna communication system utilizing orthogonal frequency division multiplexing (OFDM), comprising:
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a data processor operative to process a data packet to obtain a block of data symbols;
a demultiplexer operative to demultiplex pilot symbols and the block of data symbols onto a plurality of subbands to obtain, for the data packet, a plurality of sequences of pilot and data symbols for the plurality of subbands; and
a spatial processor operative to perform spatial processing on the sequence of pilot and data symbols for each subband with at least one steering vector selected for the subband, the spatial processing randomizing a plurality of effective single-input single-output (SISO) channels observed by the plurality of sequences of pilot and data symbols sent on the plurality of subbands. - View Dependent Claims (16, 17, 18, 19)
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20. An apparatus in a wireless multi-antenna communication system utilizing orthogonal frequency division multiplexing (OFDM), comprising:
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means for processing a data packet to obtain a block of data symbols;
means for demultiplexing pilot symbols and the block of data symbols onto a plurality of subbands to obtain, for the data packet, a plurality of sequences of pilot and data symbols for the plurality of subbands; and
means for performing spatial processing on the sequence of pilot and data symbols for each subband with at least one steering vector selected for the subband, the spatial processing randomizing a plurality of effective single-input single-output (SISO) channels observed by the plurality of sequences of pilot and data symbols sent on the plurality of subbands. - View Dependent Claims (21, 22, 23, 24)
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25. A method of transmitting data from a transmitting entity to a receiving entity in a wireless multiple-input multiple-output (MIMO) communication system utilizing orthogonal frequency division multiplexing (OFDM), comprising:
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processing a data packet to obtain a block of data symbols;
demultiplexing pilot symbols and the block of data symbols onto a plurality of subbands; and
performing spatial processing on the pilot and data symbols for each subband with at least one steering matrix selected for the subband, the spatial processing randomizing a plurality of effective MIMO channels for the plurality of subbands observed by the pilot and data symbols sent on the plurality of subbands. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32, 33, 34, 35)
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36. An apparatus in a wireless multiple-input multiple-output (MIMO) communication system utilizing orthogonal frequency division multiplexing (OFDM), comprising:
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a data processor operative to process a data packet to obtain a block of data symbols;
a demultiplexer operative to demultiplex pilot symbols and the block of data symbols onto a plurality of subbands; and
a spatial processor operative to perform spatial processing on the pilot and data symbols for each subband with at least one steering matrix selected for the subband, the spatial processing randomizing a plurality of effective MIMO channels for the plurality of subbands observed by the pilot and data symbols sent on the plurality of subbands.
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37. A method of transmitting data from a transmitting entity to a receiving entity in a wireless multi-antenna communication system utilizing orthogonal frequency division multiplexing (OFDM), comprising:
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transmitting data to the receiving entity using a first mode if channel response estimates for the receiving entity are unavailable to the transmitting entity, wherein data symbols are spatially processed with pseudo-random steering vectors or matrices in the first mode; and
transmitting data to the receiving entity using a second mode if the channel response estimates for the receiving entity are available to the transmitting entity, wherein data symbols are spatially processed with steering vectors or matrices derived from the channel response estimates in the second mode. - View Dependent Claims (38, 39, 40, 41)
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42. An apparatus in a wireless multi-antenna communication system utilizing orthogonal frequency division multiplexing (OFDM), comprising:
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a controller operative to select a first mode for data transmission to a receiving entity if channel response estimates for the receiving entity are unavailable and select a second mode for data transmission to the receiving entity if the channel response estimates are available, wherein data symbols are spatially processed with pseudo-random steering vectors in the first mode and with steering vectors derived from the channel response estimates in the second mode; and
a spatial processor operative to perform spatial processing for each block of data symbols in accordance with the mode selected for the block.
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43. A method of receiving a data transmission sent by a transmitting entity to a receiving entity in a wireless multiple-antenna communication system utilizing orthogonal frequency division multiplexing (OFDM), comprising:
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obtaining, via a single receive antenna, S sequences of received symbols for S sequences of pilot and data symbols transmitted via S subbands by the transmitting entity, where S is an integer greater than one, and wherein the S sequences of pilot and data symbols are spatially processed with a plurality of steering vectors at the transmitting entity to randomize S effective single-input single-output (SISO) channels observed by the S sequences of pilot and data symbols;
deriving channel response estimates for the S effective SISO channels based on received pilot symbols in the S sequences of received symbols; and
performing detection on received data symbols in the S sequences of received symbols based on the channel response estimates for the S effective SISO channels to obtain detected symbols. - View Dependent Claims (44, 45, 46, 47)
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48. A receiver apparatus in a wireless multiple-antenna communication system utilizing orthogonal frequency division multiplexing (OFDM), comprising:
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a demodulator operative to provide S sequences of received symbols, obtained via a single received antenna, for S sequences of pilot and data symbols transmitted via S subbands by a transmitting entity, where S is an integer greater than one, and wherein the S sequences of pilot and data symbols are spatially processed with a plurality of steering vectors at the transmitting entity to randomize S effective single-input single-output (SISO) channels observed by the S sequences of pilot and data symbols;
a channel estimator operative to derive channel response estimates for the S effective SISO channels based on received pilot symbols in the S sequences of received symbols; and
a detector operative to perform detection on received data symbols in the S sequences of received symbols based on the channel response estimates for the S effective SISO channels to obtain detected symbols. - View Dependent Claims (49, 50, 51)
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52. A receiver apparatus in a wireless multiple-antenna communication system utilizing orthogonal frequency division multiplexing (OFDM), comprising:
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means for obtaining, via a single receive antenna, S sequences of received symbols for S sequences of pilot and data symbols transmitted via S subbands by a transmitting entity, where S is an integer greater than one, and wherein the S sequences of pilot and data symbols are spatially processed with a plurality of steering vectors at the transmitting entity to randomize S effective single-input single-output (SISO) channels observed by the S sequences of pilot and data symbols;
means for deriving channel response estimates for the S effective SISO channels based on received pilot symbols in the S sequences of received symbols; and
means for performing detection on received data symbols in the S sequences of received symbols based on the channel response estimates for the S effective SISO channels to obtain detected symbols. - View Dependent Claims (53, 54, 55)
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56. A method of receiving a data transmission sent by a transmitting entity to a receiving entity in a wireless multiple-input multiple-output (MIMO) communication system utilizing orthogonal frequency division multiplexing (OFDM), comprising:
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obtaining, via R receive antennas at the receiving entity, S sets of R sequences of received symbols for S sets of T sequences of pilot and data symbols transmitted on S subbands of T transmit antennas by the transmitting entity, one set of R sequences of received symbols and one set of T sequences of pilot and data symbols for each subband, where R, S, and T are integers greater than one, and wherein the set of T sequences of pilot and data symbols for each subband is spatially processed with at least one steering matrix at the transmitting entity to randomize an effective MIMO channel observed by the set of T sequences of pilot and data symbols;
deriving a channel response estimate for the effective MIMO channel for each subband based on received pilot symbols in the S sets of R sequences of received symbols; and
performing receiver spatial processing on received data symbols in the set of R sequences of received symbols for each subband with the channel response estimate for the effective MIMO channel for the subband to obtain detected symbols for the subband. - View Dependent Claims (57, 58, 59, 60, 61, 62)
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63. A receiver apparatus in a wireless multiple-input multiple-output (MIMO) communication system utilizing orthogonal frequency division multiplexing (OFDM), comprising:
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a plurality of (R) demodulators operative to provide received pilot symbols and received data symbols obtained for R receive antennas, wherein S sets of R sequences of received symbols are obtained, via the R receive antennas, for S sets of T sequences of pilot and data symbols transmitted on S subbands of T transmit antennas by a transmitting entity, one set of R sequences of received symbols and one set of T sequences of pilot and data symbols for each subband, where R, S, and T are integers greater than one, and wherein the set of T sequences of pilot and data symbols for each subband is spatially processed with at least one steering matrix at the transmitting entity to randomize an effective MIMO channel observed by the set of T sequences of pilot and data symbols;
a channel estimator operative to derive a channel response estimate for an effective MIMO channel for each subband based on the received pilot symbols and steering matrices used for data transmission by the transmitting entity; and
a spatial processor operative to perform receiver spatial processing on received data symbols for each subband based on the channel response estimate for the effective MIMO channel for the subband to obtain detected symbols for the subband.
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64. A receiver apparatus in a wireless multiple-input multiple-output (MIMO) communication system utilizing orthogonal frequency division multiplexing (OFDM), comprising:
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means for obtaining, via R receive antennas, S sets of R sequences of received symbols for S sets of T sequences of pilot and data symbols transmitted on S subbands of T transmit antennas by a transmitting entity, one set of R sequences of received symbols and one set of T sequences of pilot and data symbols for each subband, where R, S, and T are integers greater than one, and wherein the set of T sequences of pilot and data symbols for each subband is spatially processed with at least one steering matrix at the transmitting entity to randomize an effective MIMO channel observed by the set of T sequences of pilot and data symbols;
means for deriving a channel response estimate for the effective MIMO channel for each subband based on received pilot symbols in the S sets of R sequences of received symbols; and
means for performing receiver spatial processing on received data symbols in the set of R sequences of received symbols for each subband with the channel response estimate for the effective MIMO channel for the subband to obtain detected symbols for the subband.
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Specification