(12) Unlted States Patent
`(10) Patent N0.:
`US 7,570,696 B2
`
`Maltsev et al.
`(45) Date of Patent:
`Aug. 4, 2009
`
`USOO7570696B2
`
`(54) NIUIATIPIrE INPUT lVIUIrTIPIrE OUTPUT
`MULTICARRIER COMMUNICATION
`SYSTEM AND METHODS WITH QUANTIZED
`BEAMFORMING FEEDBACK
`
`(75)
`
`Inventors: Alexander A. Maltsev, Nizhny
`Novgorod (RU); Ali S Sadri, San Diego,
`CA (US); Sergey A. Tiraspolsky,
`Nizlmy Novgorod (RU); Alexander
`Flaksman, Nizhny Novgorod (RU);
`Alexei V Davydov, Nizhny Novgorod
`(RU)
`
`(73) Assignee:
`
`Intel Corporation, Santa Clara, CA
`(US)
`
`( * ) Notice:
`
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U-S-C- 154(1))1’3’ 1240 days-
`
`EP
`
`6,321,073 B1
`6,473,467 B1
`6,498,929 B1
`6,717,981 B1
`6,876,859 B2
`6,927,728 B2 *
`7,085,587 B2
`7,196,579 B2
`7,409,189 B2
`2001/0033622 A1
`2002/0094792 A1
`2003/0064696 Al
`2003/0181170 A1
`
`11/2001 Luz et a1,
`10/2002 Wallace et a1.
`12/2002 Tsurumi et a1.
`4/2004 Mohindra
`4/2005 Anderson et al.
`8/2005 Vook et a1.
`.................. 342/377
`8/2006 Oono ct a1.
`3/2007 Ozawa
`8/2008 Song
`10/2001 Jongren et al
`7/2002 Oono et a1.
`4/2003 Akamine et a1.
`9/2003 Sim
`
`(21) App1.No.: 10/877,943
`
`(22) Filed:
`
`Jun. 25, 2004
`
`(65)
`
`(51)
`
`Prior Publication Data
`
`US 2005/0287978 A1
`Int. Cl.
`H04L 27/28
`
`DeC- 29. 2005
`
`(2006.01)
`
`(52) US. Cl.
`...................................................... 375/260
`
`(58) Field of Classification Search .......... 375/260,
`375/347, 267, 147, 150, 149, 455/403, 562.],
`455/101, 102, 103, 69, 73, 342/372, 368,
`342/377, 383
`Scc application file for complete scarch history.
`
`(56)
`
`Rafel‘ences Cited
`U.S. PATENT DOCUMENTS
`
`5,001,776 A
`5,417,665 A
`5,471,665 A
`5,898,912 A
`6,052,085 A *
`
`3/1991 Clark
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`11/1995 Pace et a1.
`4/1999 Heck et a1.
`4/2000 Hanson et 31.
`
`.............. 342/373
`
`(Continued)
`
`
`
`FOREIGN PATiNl DOCUMiNTS
`1416688 A1
`/2004
`
`(commued)
`OTHER PUBLICATIONS
`
`Stcphcns, A. P., “IEEE 802.11 TGn Comparison Criteria”, IEEE
`802.11—02/8147'2, (IEEE P802.17Wireless LANs),(N0V. 2003),5
`S.
`pg
`
`(Continued)
`
`Primary ExamineriKhai Tran
`(74) A Itorney, Agent, or Firm Schwegman, Lundberg &
`Woessner, PA; Gregory J. Gorrie
`
`(57)
`
`ABSTRACT
`
`A multicarrier receiver generates a quantized transmit beam-
`former matrix (V) for each subcarrier of a multicarrier com—
`munication channel for use by a multicarrier transmitting
`station. The multicarrier receiver applies a corrected receiver
`beamformer matrix (UH) to received subcarriers signals gen-
`erated by signals received from the transmitting station.
`
`34 Claims, 11 Drawing Sheets
`
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`ZTE, Exhibit 1006-0001
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`ZTE, Exhibit 1006-0001
`
`

`

`US 7,570,696 B2
`Page 2
`
`U.S. PATENT DOCUMENTS
`2004/0087324 A1
`5/2004 Ketchum et al
`2004/0120411 A1
`6/2004 Walton et a1.
`2004/0157573 A1
`8/2004 Lee et a1.
`2005/0181754 A1
`8/2005 Wu et a1.
`2005/0208919 A1
`9/2005 Walker et al.
`2005/0221763 A1
`10/2005 Song
`2006/0114816 A1
`6/2006 MaltseV et a1.
`2006/0120469 A1
`6/2006 MaltseV et a1.
`2007/0047634 A1
`3/2007 Kang el al.
`........ 375/260
`2007/0230595 A1* 10/2007 Waxman ..
`
`FOREIGN PATENT DOCUMENTS
`VVO-2005/029804 A2
`3/2005
`WO-2006/007299 A1
`1/2006
`VVO-2006/060241 A1
`6/2006
`
`\VO
`WO
`“’0
`
`
`
`OTHER PUBLICATIONS
`
`“International Search Report for corresponding PCT Application No.
`PCT/CS2005/019884”. (Sep. 23. 2005),4 pgs.
`Bangerter, B., et a1., “W'ireless Technologies: High-Throughput
`Wireless LAN Air Interface”. Intel Technology Journal. 7(3). (Aug.
`19, 2003).,47-57.
`
`Jongren, G., et al., “Utilizing Quantized Feedback Information In
`Orthogonal Space-Time Block Coding”, Proceedings ofIEEE Glo—
`bal Telecommunication Conference, GLOBECOM ’00. 2(4), (Nov.
`27, 2000),995-999.
`Love. David J., et a1., “Grassmannian Beamforming for Multiple—
`Input Multiple-Output Wireless Systems”, IEEE Transactions on
`Information Theory, vol. 49, No. 10. (Oct. 2003), 2735-2747.
`US. Appl. No. 10/812,834, Final Office Action Mailed Dec. 31,
`2007, 17 pgs.
`U.S. Appl. No. 10/812.834 Non-Final Office Action mailed Jul. 9.
`2007, 13 pgs.
`
`U.S. Appl. No. 10/812,834 Response filed Feb. 11, 2008 to Final
`0 Ice Action mailed Dec. 31, 2007, 8 pgs.
`U.S.App1.No. 10/812,834 Response filed Oct. 9, 2007 lo Non-Final
`0 Ice Action mailed Jul. 9. 2007. 12 pgs.
`Korean Office Action, Korean Application No 2006-7027306, (Ian.
`31, 2008), 4 pgs.
`Bangerter, B.
`, et a1., “High-'l'hroughput Wireless LAN Air Inter-
`face”, Inlel Technology Journal. 7(3), htlp://developer.inle1.com/
`technology/itj/index.htm,(Aug. 9, 2003),47-57.
`International Search Report,
`“Application No. PCT/ITSZOOS/
`019884, ”, (Sep. 23, 2005),4 pgs.
`“US Appl. No. 10/812.834 Notice of Allowance mailed Mar. 25,
`2008”, 9 Pgs.
`* cited by examiner
`
`
`
`
`ZTE, Exhibit 1006-0002
`
`ZTE, Exhibit 1006-0002
`
`

`

`US. Patent
`
`Aug. 4, 2009
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`US 7,570,696 B2
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`Aug. 4, 2009
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`Aug. 4, 2009
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`US. Patent
`
`Aug. 4, 2009
`
`Sheet 5 of 11
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`US 7,570,696 B2
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`

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`US. Patent
`
`Aug. 4, 2009
`
`Sheet 6 of 11
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`US 7,570,696 B2
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`US. Patent
`
`Aug. 4, 2009
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`

`

`US. Patent
`
`Aug. 4, 2009
`
`Sheet 8 of 11
`
`US 7,570,696 B2
`
`TRANSMITTING STATION PROCEDURE
`
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`
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`MATRICES (V) FROM RECEIVING STATION
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`US. Patent
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`Aug. 4, 2009
`
`Sheet 9 of 11
`
`US 7,570,696 B2
`
`RECEIVING STATION PROCEDURE
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`TRANSMITTING STATION
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`Aug. 4, 2009
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`US 7,570,696 B2
`
`1
`MULTIPLE INPUT MULTIPLE OUTPUT
`MULTICARRIER COMMUNICATION
`SYSTEM AND METHODS WITH QUANTIZED
`BEAMFORMIN G FEEDBACK
`
`TECHNICAL FIELD
`
`Embodiments of the present invention pertain to wireless
`communications, and in some embodiments, to multicarrier
`commlmications.
`
`BACKGROUND
`
`Wireless communication systems conventionally use feed-
`back to allow a transmitting station to adapt it’ s transmissions
`to changing chalmel conditions. One problem with multicar—
`rier communication systems that use many subcarriers, such
`as systems employing orthogonal frequency division multi-
`plexed (OFDM) signals, is that the channel conditions may be
`different for each of the subcarriers. The amount of feedback
`to adapt to changing channel conditions may be significant
`and consumes bandwidth as well as uses additional energy.
`This is especially a concern when multiple antennas are used
`to communication additional data streams over the same sub-
`carriers, as in the case of multiple input multiple output
`(MIMO) systems. Thus, there are general needs for systems
`and methods that may adapt to changing channel conditions
`with less feedback.
`
`
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`The appended claims are directed to some of the various
`embodiments of the present invention. However, the detailed
`description presents a more complete understanding of
`embodiments of the present invention when considered in
`connection with the figures, wherein like reference numbers
`refer to similar items throughout the figures and:
`FIG. 1 is a block diagram of a multicarrier transmitter in
`accordance with some embodiments ofthe present invention;
`FIG. 2 is a block diagram of a multicarrier receiver in
`accordance with some embodiments ofthe present invention;
`FIGS. 3A and 3B illustrate quantization schemes in accor-
`dance with some embodiments of the present invention;
`FIGS. 4A and 4B illustrate amplitude and phase subfields
`of quantized beamforming coefficients in accordance with
`some embodiments of the present invention;
`FIG. 5 illustrates channel measurements for use in gener-
`ating quantized beamformer coefficients for groups of sub-
`carriers in accordance with some embodiments ofthe present
`invention;
`FIGS. 6A and 6B illustrate quantized transmit beamform-
`ing coefficients in accordance with some embodiments of the
`present invention;
`FIG. 7 is a flow chart ofa multicarrier signal transmission
`procedure in accordance with some embodiments of the
`present invention;
`FIG. 8 is a flow chart of a multicarrier signal reception
`procedure in accordance with some embodiments of the
`present invention;
`FIG. 9 is a functional diagram illustrating the operation of
`a 4x2 multiple-input multiple-output (MIMO) orthogonal
`frequency division multiplexed (OFDIVI) transmitter in accor-
`dance with some embodiments of the present invention; and
`FIG. 10 is a functional diagram illustrating the operation of
`a multiple-input multiple-output (MIMO) orthogonal fre-
`
`10
`
`15
`
`'
`
`30
`
`35
`
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`
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`
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`quency division multiplexed (OFDM) receiver in accordance
`with some embodiments of the present invention.
`
`DETAILED DESCRIPTION
`
`
`
`The following descrip ion and the drawings illustrate spe-
`cific embodiments of the invention sufficiently to enable
`those skilled in the art to practice them. Other embodiments
`may incorporate structural, logical, electrical, process, and
`other changes. Examples merely typify possible variations.
`Individual components and functions are optional Lmless
`explicitly required, and the sequence of operations may vary.
`Portions and features of some embodiments may be included
`in or substituted for those of others. Embodiments of the
`invention may be referred to, individually or collectively,
`herein by the term “invention” merely for convenience and
`without intending to voluntarily limit the scope ofthis appli-
`cation to any single invention or inventive concept if more
`than one is in fact disclosed.
`FIG. 1 is a block diagram of a multicarrier transmitter in
`accordance with some embodiments ofthe present invention.
`Multicarrier transmitter 100 may be part of a wireless com—
`munication device and may transmit multicarrier communi-
`cation signals comprising a plurality of subcarriers, such as
`orthogonal frequency division multiplexed (OFDM) commu-
`nication signals, although the scope of the invention is not
`limited in this respect.
`In accordance with some embodiments, multicarrier trans-
`mitter 100 may apply quantized transmit beamfonning coef-
`ficients to symbol-modulated subcarriers of a multicarrier
`communication signal in a signal path before an inverse Fou—
`rier transform (IFFT) is performed on the subcarriers. The
`quantized transmit beamforming coefficients may comprise
`predetermined numbers of bits for each subcarrier indicating
`amounts to weight an amplitude and shift a phase of an
`associated symbol—modulated subcarrier. In some embodi—
`ments, multicarrier transmitter 100 may comprise a plurality
`of transmit subcarrier beamformers 108 to apply the quan-
`tized transmit beamforming coefficients to symbol-modu-
`lated subcarriers 107.
`In some embodiments, the transmit subcarrier beamform—
`ers 1 08 may apply the quantized transmit beamforming coef-
`ficients in the frequency domain to frequency-domain sym-
`bol-modulated subcarriers 107 before an IFFT is performed
`on the symbol—modulated subcarriers. In some embodiments,
`a quantized transmit beamformer matrix (V) generated by a
`receiving station includes the transmit beamforming coeffi—
`cients. In some embodiments,
`the transmit beamforming
`coefficients may be complex values.
`The use of quantized transmit beamforming eoefiicients
`may significantly reduce the amount of feedback provided by
`a receiving station. In some embodiments. closed loop adap-
`tive beamforming may performed by transmitter 100. The
`adaptive beamforming may generate signals for different spa-
`tial channels by taking into account multipath differences in
`the communication channel. Another purpose of the adaptive
`beamforming is to take into account the channel conditions
`(i.e., adapt to changing channel conditions of a fading chan-
`nel) as well as take into account channel conditions between
`the transmitting and receiving stations.
`In some embodiments, multicarrier transmitter 1 00 may be
`part ofa closed loop multiple-input multiple-output (MIMO)
`system that performs adaptive beamforming based on singu-
`lar value decomposition (SVD). In these embodiments, the
`MIMO system may be viewed as a plurality of decoupled
`(independent or orthogonal)
`single-input
`single-output
`(SISO) systems referred to as orthogonal spatial channels.
`
`ZTE, Exhibit 1006-0014
`
`ZTE, Exhibit 1006-0014
`
`

`

`US 7,570,696 B2
`
`10
`
`15
`
`3
`The number of orthogonal spatial channels is generally not
`greater than a minimum number of transmit and minimum
`number of receive antennas.
`In accordance with some
`embodiments of this invention, the spatial channels may be
`substantially orthogonal. The substantial orthogonality is
`achieved by applying appropriate transmit and receive beam—
`forming coefficients.
`In some embodiments, encoded bit stream 103 may be
`separated by bit demultiplexer of circuitry 104 into several
`flows (data streams) in accordance with the number of spatial
`chamiels. These flows may be referred to as spatial bit streams
`and may comprise the same number of bits when identical
`modulation and/or coding schemes are used for each of the
`spatial channels. The spatial bit streams may contain different
`numbers of bits when different modulation and/or coding
`schemes are used for each of the spatial chamiels, although
`the scope of the invention is not limited in this respect.
`In some embodiments, each spatial channel may be used
`communicate separate and/or independent data streams on
`the same subcarriers as the other spatial cha1mels allowing the
`transmission of additional data without an increase in fre-
`quency bandwidth. The use of spatial channels takes advan-
`tage of the multipath characteristics of the channel.
`In accordance with closed loop MIMO embodiments ofthe
`present invention, when spatial channels are substantially ,
`orthogonal, each spatial channel may be associated with a
`beamforming pattern, rather than an antenna, Signals in each
`spatial cha1mel may be transmitted from the available anten—
`nas simultaneously. In other words, each antenna may trans—
`mit signals with different weights which are specific to the
`individual antenna. Examples of these embodiments are
`described in more detail below.
`In some embodiments, multicarrier transmitter 100 may
`comprise encoder 102, which may be a forward error correct-
`ing (FEC) encoder, to apply error-correcting codes to bit
`stream 101 and generate encoded bit stream 103. In some
`embodiments, multicarrier transmitter 100 may also com-
`prise bit demultiplexer and interleaver circuitry 104 to per—
`mute bits of encoded bit stream 103 and demultiplex the bits
`into a plurality of spatial/frequency chamiels.
`In some
`embodiments, permuted bits may be separated by bit demul-
`tiplexer of circuitry 104 into one or more spatial streams
`associated with each spatial channel. Each of the spatial
`streams may be permuted by an interleaver of circuitry 104 in
`accordance with an interleaving pattern. Then, bit demulti-
`plexer of circuitry 104 may separate each of the permuted
`spatial streams into groups for modulation on the data sub—
`carriers of the multicarrier communication channel. The
`grouping of bits may depend on the modulation levels for the
`subcarrier and may be provided by processing circuitry 116,
`although the scope of the invention is not limited in this
`respect.
`In some embodiments, multicarrier transmitter 100 may
`also comprise symbol mapping circuitry 106 for each spatial
`stream and’or spatial chamiel to generate symbol-modulated
`subcarriers 107 from spatial channel multiplexed bit streams
`105. Transmit subcarrier beamformers 108 may be associated
`with each subcarrier ofthe multicarrier commtmication chan-
`nel and may apply quantized transmit beamforming COClTl-
`cients 118 to each subcarrier signal to generate frequency—
`domain symbol-modulated subcarriers 109 for each transmit
`anterma 114.
`In some embodiments, multicarrier transmitter 100 may
`also comprise inverse fast Fourier transform circuitry (IFFT)
`circuitry 110 for each transmit antenna 114 to perfomi an
`IFFT on symbol-modulated subcarriers 109 after application
`of quantized transmit beamfonning coefficients 1 18 by trans-
`
`4
`mit subcarrier beamformers 108 to generate time—domain
`samples 111 for each transmit antenna 114. In some embodi-
`ments, a cyclic extension may be added to time-domain
`samples 111 to help reduce the effects of intersymbol inter-
`ference, although the scope of the invention is not limited in
`this respect.
`In some embodiments, multicarrier transmitter 100 may
`also comprise digital to analog conversion (DAC) circuitry
`and radio-frequency (RF) circuitry 112 which may be asso-
`ciated with one of transmit antennas 114. Circuitry 112 may
`generate RF signals for transmission from time—domain
`samples 111 generated by the IFFT circuitry 10.
`In some embodiments, multicarrier transmitter 100 may
`also comprise processing circuitry 116 to provide transmit
`parameters to various elements of transmitter 100. For
`example, processing circuitry 116 may provide interleaving
`parameters 120 for the interleaver of circuitry 104, subcarrier
`modulation levels 122 to each of symbol mapping circuitry
`106, IFFT size information 124 to IFFT circuitry 110, and
`code type and/or coding rate information 126 to encoder 102,
`although the scope of the invention is not limited in this
`respect. In some embodiments, circuitry 116 may assign the
`transmit parameters based on channel feedback information
`115 received from another communication station for fast
`link adaptation.
`In some embodiments, transmit antennas 114 may be used
`for transmitting a plurality of spatial streams on a plurality of
`spatial channels over the multicarrier communication chan—
`nel. In these embodiments, the number of the spatial streams
`and/or spatial channels may be less than or equal to the
`number of the transmit antennas. In some embodiments, four
`antennas 114 may be used to transmit up to four spatial
`streams over corresponding spatial channels, although the
`scope of the present invention is not limited in this respect.
`In some embodiments, the quantized transmit beamform—
`ing coefficients for each subcarrier may represent a quantized
`transmit beamforming matrix (V) for each subcarrier. In some
`embodiments, each quantized transmit beamfonning matrix (
`V) may be a unitary matrix having a number ofrows equaling
`the munber of the transmit antennas, and a number of col-
`umns equaling the number of the spatial streams (or spatial
`channels). As used herein, the use of the terms “rows” and
`“colurrms” is interchangeable.
`In some embodiments, elements of each quantized trans—
`mit beamforming matrix (V) may comprise an amplitude
`subfield and a phase subfield with each field having predeter-
`mined numbers of bits. In some embodiments, the amplitude
`subfield represents the square of the amount to weight the
`amplitude of an associated symbol—modulated subcarrier.
`This is discussed more detail below with reference to FIGS.
`4A and 4B. Some embodiments may use uniform quantiza-
`tion of the square amplitudes of the transmit beamforming
`coefficients. This uniform quantization may be near to opti-
`mal for a typical random Rayleigh indoor channel because the
`square amplitudes of the transmit beamfomiing coefficients
`have a distribution that is close to uniform.
`
`In some embodiments, multicarrier transmitter 100 may be
`part of a transmitting station and may receive cha1mel feed-
`back information 115 comprising a quantized transmit beam-
`forming matrix (\7) for each subcarrier from a receiving sta-
`tion. In these embodiments, processing circuitry 116 may
`provide quantized transmit beamforming coefficients 118
`from the quantized transmit beamforming matrix (V) to a
`corresponding one of transmit subcarrier beamfomiers 108.
`In these embodiments, the receiving station may measure
`signals received from transmitter 100 to estimate a channel
`
`ZTE, Exhibit 1006-0015
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`ZTE, Exhibit 1006-0015
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`

`

`US 7,570,696 B2
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`transfer matrix CI) for each subcarrier of the multicarrier
`communication chalmel, and may generate the quantized
`beamforming matrix (V) for each subcarrier from the channel
`transfer matrix (H). In these embodiments, the receiving sta-
`tion may transmit the quantized beamforrning matrix (V) for
`each subcarrier to the transmitting station in a response
`packet, although the scope of the invention is not limited in
`this rcspcct. In some of thcsc cmbodimcnts, thc rccciving
`station may measure a preamble of a packet received from the
`transmitting station to estimate the channel transfer matrix
`(H) for each subcarrier of the multicarrier communication
`channel. In some embodiments, the receiving station may
`measure a physical
`layer convergence protocol
`(PLCP)
`header of a packet received from the transmitting station to
`estimate the channel transfer matrix (H) for each subcarrier,
`althougi the scope of the invention is not limited in this
`rcspcct. In somc of thcsc cmbodimcnts, thc rccciving station
`may perform a singular value decomposition (SVD) on the
`chamiel transfer matrix (H) to generate the quantized beam-
`forming matrix (V) for each subcarrier. These embodiments
`are discussed in more detail below.
`In some embodiments, the predetermined numbers of bits
`comprising the quantized beamforming matrix (V) may be
`lower during initial portions of a packet exchange between a
`transmitting station and a receiving station (i.e., during a '
`coarsc quantization modc) and may be greater during subsc-
`quent portions of the packet exchange (i.e., during a fine
`quantization mode). In this way, a transmitting station may
`quickly adjust to the channel conditions and may subse-
`quently fine tune its transmissions as time goes on allowing
`for faster link adaptation.
`In some embodiments, elements of the quantized beam-
`forming matrix 0N7) may represent differences from previ-
`ously received beamforrning coefficients. In some embodi—
`ments, the quantized beamformer coefficients may be applied
`to groups of subcarriers. These embodiments are described in
`more detail below.
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`In some embodiments, multicarrier transmitter 100 (FIG.
`1) and/or multicarrier receiver 200 (FIG. 2) may communi-
`catc over a widcband multicarricr communication channcl.
`The wideband channel may comprise one or more multicar—
`rier subcha1mels. The subchannels may be frequency-divi-
`sion multiplexed (i.e. , separated in frequency from other sub-
`channels) and may be within a predetermined frequency
`spectrum. The subchannels may comprise a plurality of
`orthogonal subcarriers. In some embodiments, the orthogo-
`nal subcarriers of a subcharmel may be closely spaced OFDM
`subcarriers. To achieve orthogonality between closely spaced
`subcarricrs, in somc cmbodimcnts, thc subcarricrs of a par-
`ticular subchannel may have a null at substantially a center
`frequency of the other subcarriers of that subchamiel.
`In some embodiments, multicarrier transmitter 100 (FIG.
`1) and/or multicarrier receiver 200 (FIG. 2) may communi-
`cate with one or more other communication stations over a
`multicarrier communication comprising either a standard-
`throughput channel or a high—throughput communication
`chamiel.
`In these embodiments,
`the standard-throughput
`channel may comprise one subcharmel and the high-through-
`put channel may comprise a combination of one or more
`subchalmcls and/or one or morc spatial channels associatcd
`with each subchannel. Spatial channels may be non—orthogo—
`nal channels (i.e.. not separated in frequency) associated with
`a particular subcharmel
`in which orthogonality may be
`achieved through beamforming and/or diversity.
`In accordance with some embodiments, mappers 106 (FIG.
`1) may symbol-modulate the subcarriers in accordance with
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`individual subcarrier modulation assignments. This may be
`referred to as adaptive bit loading (ABL) . Accordingly, one or
`more bits may be represented by a symbol modulated on a
`subcarrier, The modulation assignments for the individual
`subchanncl may bc based on thc channcl charactcristics or
`channel conditions for that subcarrier, although the scope of
`the invention is not limited in this respect. In some embodi-
`ments,
`the subcarrier modulation assignments may range
`from 7ero bits per symbol to up to ten or more bits per symbol.
`In terms of modulation levels, the subcarrier modulation
`assignments may comprise binary phase shift keying
`(BPSK), which communicates one bit per symbol, quadrature
`phase shift keying (QPSK), which communicates two bits per
`symbol, 8PSK, which communicatcs thrcc bits pcr symbol,
`16—quadrature amplitude modulation (1 6—QAM), which com—
`municates four bits per symbol, 32-QAM, which communi-
`cates five bits per symbol, 64-QAM, which communicates six
`bits per symbol, l28-QAM, which communicates seven hits
`per symbol, and 256—QAM, which communicates eight bits
`per symbol. Modulation orders with higher data communica—
`tion rates per subcarrier may also be used.
`In some embodiments, the frequency spectrtuns for the
`multicarrier communication channcl may compri sc subchan-
`nels in either a 5 GHz frequency spectrum or a 2.4 GHz
`frequency spectrum. In these embodiments, the 5 GHz fre-
`quency spectrum may include frequencies ranging from
`approximately 4.9 to 5.9 GIIz, and the 2.4 GHz spectrummay
`include frequencies ranging from approximately 2.3 to 2.5
`GHz, although the scope ofthe invention is not limited in this
`respect, as other frequency spectrums are also equally suit-
`able.
`In some embodiments, multicarrier transmitter 100 (FIG.
`1) and/or multicarrier receiver 200 (FIG. 2) may be part of a
`wireless communication device. The wireless communica-
`tion device may, for example, be a personal digital assistant
`(FDA), a laptop or portable computer with wireless commu-
`nication capability, a wcb tablct, a wirclcss tclcphonc, a wirc-
`less headset, a pager, an instant messaging device, a digital
`camera, an access point or other device that may receive
`and/or transmit information wirelessly. In some embodi-
`ments, the wireless communication device may transmit and/
`or receive RF communications in accordance with specific
`communication standards, such as the Institute of Electrical
`and Electronics Engineers (IEEE) standards including IEEE
`802.1 1(a), 802.1 1(b), 802,11(g/h)and/or 802.1 1(n) standards
`for wirclcss local arca nctworks (WLANs) and/or 802.16
`standards
`for wireless metropolitan
`area
`networks
`(WMANs), although the wireless communication device
`may also be suitable to transmit and/or receive commtmica-
`tions in accordance with other techniques including the Digi-
`tal Video Broadcasting Terrestrial
`(DVB—T) broadcasting
`standard, and the High performance radio Local Area Net-
`work (HiperLAN) standard.
`Antennas 114 (FIG. 1) and antennas 202 (FIG. 2) may
`comprisc dircctional or omnidircctional antcnnas, including,
`for example, dipole antemias, monopole antennas,
`loop
`antennas, microstrip antelmas or other type of antennas suit-
`able for reception and/or transmission of RF signals.
`Although some embodiments of the present invention are
`discussed in the context of an 802.11x implementation (e. g.,
`802.1 la, 802.11g, 802.11 HT, etc.), the scope ofthe present
`invention is not limited in this respect. Some embodiments of
`the present invention may be implemented as part of any
`wirclcss system using multicarricr wirclcss communication
`channels (e.g., orthogonal frequency—division multiplexing
`(OFDM). discrete multi-tone modulation (DMT), etc.), such
`as may be used within, without limitation, a wireless personal
`
`ZTE, Exhibit 1006-0016
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`ZTE, Exhibit 1006-0016
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`US 7,570,696 B2
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`area network (WPAN), a wireless local area network
`(WLAN), a wireless metropolitan are network (WMAN), a
`wireless wide area network (WWAN), a cellular network, a
`third generation (3(3) network, a fourth generation (40) net-
`work, a universal mobile telephone system (UMTS), and the
`like communication systems.
`Although multicanier transmitter 100 (FIG. 1) and multi—
`carrier receiver 200 (FIG. 2) are illustrated as having several
`separate functional elements, one or more of the functional
`elements may be combined and may be implemented by
`combinations of software—configured elements, such as pro—
`cessing elements including digital signal processors GDSPs),
`and/or other hardware elements. For example, some elements
`may comprise one or more microprocessors, DSPs, applica-
`tion specific integrated circuits (ASICs), and combinations of
`various hardware and logic circuitry for performing at least
`the functions described herein.
`FIG. 2 is a block diagram of a multicarrier receiver in
`accordance with some embodiments of the present invention,
`Multicarrier receiver 200 may be part of a wireless commu-
`nication device, and may receive multicarrier communication
`signals comprising a plurality of subcarriers. such as OFDM
`communication signals, although the scope ofthe invention is
`not limited in this respect.
`In some embodiments, multicarrier receiver 200 may be ,
`part of a receiving station and may communicate over a mul—
`ticarrier communication channel with a transmitting station.
`The transmitting station may include a multicarrier transmit-
`ter, such as multicarrier transmitter 100 (FIG. 1).
`In other embodiments, multicarrier receiver 200 may be
`part of a multicarrier communication station that also
`includes a multicarrier transmitter, such as multicarrier trans-
`mitter 100. In these embodiments, the multicarrier commu—
`nication station may communicate with other multicarrier
`communication stations as part ofa network, such as a local
`area network, although the scope of the invention is not lim-
`ited in this respect.
`In accordance with some embodiments of the present
`invention, multicarrier receiver 200 generates a quantized
`tr