US 7,570,696 B2
`(10) Patent No.:
`a2 United States Patent
`Maltseyetal.
`(45) Date of Patent:
`Aug. 4, 2009
`
`
`US007570696B2
`
`(54) MULTIPLE INPUT MULTIPLE 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); SergeyA. Tiraspolsky.
`Nizhny 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 ofthis
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 1240 days.
`
`EP
`
`6,321,073 Bl
`6,473,467 Bl
`6,498,929 BL
`6,717,981 Bl
`6,876,859 B2
`6,927,728 B2*
`7,085,587 B2
`7,196,579 B2
`7,409,189 B2
`2001/0033622 Al
`2002/0094792 Al
`2003/0064696 Al
`2003/0181170 Al
`
`11/2001 Luzetal.
`10/2002 Wallaceetal.
`12/2002 Tsurumi et al.
`4/2004 Mohindra
`4/2005 Andersonet al.
`8/2005 Vook etal. wee 342/377
`8/2006 Oonoetal.
`3/2007 Ozawa
`8/2008 Song
`10/2001 Jongren etal
`7/2002 Oonoetal.
`4/2003 Akamineetal.
`9/2003 Sim
`
`(Continued)
`
`
`
`FOREIGN PATENT DOCUMENTS
`1416688 AL
`5/2004
`
`(Continued)
`OTHER PUBLICATIONS
`
`Stephens, A. P., “IEEE 802.11 TGn Comparison Criteria”, [EEE
`802.11-02/814r2, (IEEE P802.1—Wireless LANs),(Nav. 2003),5
`S.
`pe
`
`(Continued)
`Primary Fxaminer—Khai Tran
`(74) Attorney, Agent, or Firm Schwegman, Lundberg &
`Woessner, P.-A.; 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. lhe multicarrier receiver applies a corrected receiver
`beamformer matrix (1) to received subcarriers signals gen-
`erated by signals received from the transmitting station.
`
`(21) Appl. No.: 10/877,943
`(22) Filed:
`Jun. 25,2004
`
`(65)
`
`Prior Publication Data
`
`(51)
`
`Dec, 29, 2005
`
`US 2005/0287978 Al
`Int. Cl.
`(2006.01)
`HOAL 27/28
`(52) US. Che ci eecccceseccenescseesteseesreassescesene renee 375/260
`
`(58) Field of Classification Search................ 375/260,
`375/347, 267, 147, 150, 149; 455/403, 562.1,
`455/101, 102, 103, 69, 73; 342/372, 368,
`342/377, 383
`Sce applicationfile for complete search history.
`
`(56)
`
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`INFORUATION &
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`
`
`
`SUBCERAEROEINTERLENER Ln
`PARANETERS
`FFT SIE
`
`RIER |
`
`Ba~)
`| ae ABANETERS
`AX
`BEAMEORNER
`
`ware
`{Hy
`ree
` wt
`
`
`
`
`
`
`
`
`
`BEAMFORHER
`
`
` RX sat
`DONTERLENR |
` & MULITPLEXER
`
`
`RX_SUBCARRIERe
`FT &
`cycuc
`2s
`weyT PROCESSING
`
`
`
`EXTENSION
`
`
`
`
`REMOVAL
`AOC & RF
`
`
`Ld
`
`24
`
`ay as
` oe
`peanrorwer—|Vf
`CHANNEL
`He
`arr cacucano
`SSTIMATOR
`
`ORCUTRY
`
`220)
`Re
`
`BCAMFORMER
`
`i)
`
`CEVAPPER
`
`a
`
`ZTE, Exhibit 1006-0001
`
`ZTE, Exhibit 1006-0001
`
`

`

`US 7,570,696 B2
`
`Page 2
`
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`
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`“U.S. 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
`
`

`

`U.S. Patent
`
`Aug.4, 2009
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`U.S. Patent
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`Aug.4, 2009
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`U.S. Patent
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`Aug. 4, 2009
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`Sheet 3 of 11
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`US 7,570,696 B2
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`U.S. Patent
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`Aug.4, 2009
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`U.S. Patent
`
`Aug.4, 2009
`
`Sheet 5 of 11
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`US 7,570,696 B2
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`ZTE, Exhibit 1006-0007
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`

`

`U.S. Patent
`
`Aug.4, 2009
`
`Sheet6 of 11
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`US 7,570,696 B2
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`

`

`U.S. Patent
`
`Aug.4, 2009
`
`Sheet 7 of 11
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`ZTE, Exhibit 1006-0009
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`ZTE, Exhibit 1006-0009
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`

`

`U.S. Patent
`
`Aug.4, 2009
`
`Sheet8 of 11
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`US 7,570,696 B2
`
`TRANSMITTING STATION PROCEDURE
`
`xiv
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`MATRICES (V) FROM RECEIVING STATION
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`U.S. Patent
`
`Aug.4, 2009
`
`Sheet9 of 11
`
`US 7,570,696 B2
`
`RECEIVING STATION PROCEDURE
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`
`ESTIMATE CHANNEL FROM PREAMBLE TO GENERATE
`CHANNEL MATRIX FOR EACH SUBCARRIER
`
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`TRANSMITTING STATION
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`Aug.4, 2009
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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
`BEAMFORMING FEEDBACK
`
`TECHNICAL FIELD
`
`Embodiments of the present invention pertain to wireless
`communications, and in some embodiments, to multicarrier
`communications.
`
`BACKGROUND
`
`Wireless communication systems conventionally use feed-
`backto allowa transmitting station to adaptit’s transmissions
`to changing channel 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.
`
`a 5
`
`-
`
`
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`The appended claims are directed to some of the various
`embodimentsof 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:
`TG. 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 embodimentsofthe present invention;
`FIGS. 3A and 3B illustrate quantization schemesin accor-
`dance with some embodiments of the present invention;
`FIGS. 4A and 4Billustrate amplitude and phase subfields
`of quantized beamforming coefficients in accordance with
`some embodimentsof the present invention;
`FIG.5 illustrates channel measurements for use in gener-
`ating quantized beamformer coefficients for groups of sub-
`carricrs in accordance with some embodimentsofthe present
`invention;
`TIGS. 6A and 6Billustrate quantized transmit beamform-
`ing coefficients in accordance with some embodimentsofthe
`present invention;
`FIG. 7 is a flow chart of a multicarrier signal transmission
`procedure in accordance with some embodiments of the
`present invention;
`FIG. 8 is a flow chart of a multicarricr 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
`frequencydivision multiplexed (OFDM) 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-
`
`>
`
`2
`quencydivision multiplexed (OFDM)receiver in accordance
`with some embodiments of the present invention.
`
`DETAILED DESCRIPTION
`
`
`
`The following description and the drawingsillustrate 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 unless
`explicitly required, and the sequence of operations mayvary.
`Portions and features of some embodiments maybe 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 voluntarilylimit 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 diagramofa multicarrier transmitter in
`accordance with some embodimentsofthe 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
`orthogonalfrequency 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 beamforming 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 numbersofbits for each subcarrierindicating
`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
`oftransmit 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 108 mayapply 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 bya
`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 cocfficients
`maysignificantly reduce the amount of feedback provided by
`a receiving stalion. 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 purposeof the adaptive
`beamforming, is to take into account the channel conditions
`(1.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.
`Insome embodiments, multicarrier transmitter 100 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
`MIMOsystem 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
`
`3
`The numberof orthogonal spatial channels is generally not
`greater than a minimum numberof transmit and minimum
`number of receive antennas.
`In accordance with some
`embodiments ofthis invention, the spatial channels may be
`substantially orthogonal. The substantial orthogonality is
`achieved by applying appropriate transmit and receive beam-
`forming coelicients.
`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 numberofspatial
`channels. These flows maybereferred to as spatial bit streams
`and may comprise the same numberof bits whenidentical
`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 channels, although
`the scope ofthe invention is not limited inthis respect.
`In some embodiments, each spatial channel may be used
`communicate separate and/or independent data streams on
`the samesubcarriers as the other spatial channels allowing the
`transmission of additional data without an increase in fre-
`quencybandwidth.‘he use of spatial channels takes advan-
`tage of the multipath characteristics of the channel.
`In accordancewith closed loop MIMO embodimentsofthe
`present invention, when spatial channels are substantially 2
`orthogonal, each spatial channel may be associated with a
`beamforming pattern, rather than an antenna. Signals in each
`spatial channel 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 forwarderror correct-
`ing (FEC) encoder, to apply error-correcting codes to bit
`stream 101 and generate encoded bit stream 103. In some
`embodiments, multicarricr transmitter 100 may also com-
`prise bit demultiplexer and interleaver circuitry 104 to per-
`mule bits of encoded bit stream 103 and demulltiplex the bits
`into a plurality of spatial/frequency channels.
`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 interleaverofcircuitry 104 in
`accordance with an interleaving pattern. Then, bit demulti-
`plexer of circuitry 104 mayscparate cach 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 modulationlevels 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 symbo! mapping circuitry 106 for each spatial
`stream and/or spatial channel to generate symbol-modulated
`subcarriers 107 fromspatial channel multiplexed bit streams
`105. Transmit subcarrier beamformers 108 may be associated
`with each subcarrierofthe multicarrier communication chan-
`nel and may apply quantized transmit beamforming coeffi-
`cients 118 to each subcarrier signal to generate frequency-
`domain symbol-modulated subcarriers 109 for each transmit
`antenna 114.
`In some embodiments, multicarrier transmitter 100 may
`also comprise inverse fast Fourier transform circuitry (FFT)
`circuitry 110 for each transmit antenna 114 to perform an
`IFFT on symbol-modulated subcarriers 109 after application
`ofquantized transmit beamforming coefficients 118 by trans-
`
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`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 digilal to analog conversion (DAC) circuitry
`and radio-frequency (RF) circuitry 112 which may beasso-
`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 mayprovide interleaving
`parameters 120 for the interleaver ofcircuitry 104, subcarrier
`modulation levels 122 to each of symbol mappingcircuitry
`106, IFFT size information 124 to IFFT circuitry 110, and
`code type and/or codingrate information 126 to encoder 102,
`although the scope of the invention is not limited in this
`respect. In some embodiments, circuitry 116 mayassign 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 numberofthe spatial streams
`and/or spatial channels may be less than or equal to the
`numberofthe 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 inventionis 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 beamforming matrix (
`V) maybe a unitary matrix having a sumberofrows equaling,
`the number of the transmit antennas, and a numberofcol-
`umns equaling the numberof the spatial streams(or spatial
`channels). As used herein, the use of the terms “rows” and
`“columns”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 numbersofbits. 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 nearto opti-
`malfora typical random Rayleigh indoor channel because the
`square amplitudes of the transmit beamforming coefficients
`havea distributionthat is close to uniform.
`
`Insome embodiments, multicarrier transmitter 100 may be
`part ofa transmitting station and may receive channel feed-
`back information 115 comprising a quantized transmit beam-
`forming matrix (V) 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 beamformers 108.
`In these embodiments, the receiving station may measure
`signals received from transmitter 100 to estimate a channel
`
`ZTE, Exhibit 1006-0015
`
`ZTE, Exhibit 1006-0015
`
`

`

`US 7,570,696 B2
`
`5
`transfer matrix (H) for each subcarrier of the multicarrier
`communication channel, 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 beamforming matrix (V) for
`each subcarrier to the transmitting station in a response
`packet, although the scope of the vention is not limited in
`this respect. In some of these embodiments, the receiving
`station may measure a preamble ofa packet received from the
`transmilling 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,
`although the scope of the invention is not limited in this
`respect. In some of these embodiments, the receiving station
`may perform a singular value decomposition (SVD) on the
`channel 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 numbersof 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 (1.e., during a ©
`coarse quantization mode) and maybe greater during subse-
`quent portions of the packet exchange (i.e., during a fine
`quantization mode). In this way, a ansmilling 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 (V) may represent differences from previ-
`ously received beamforming coefficients. In some embodi-
`ments, the quantized beamformercoefficients may be applied
`to groups of subcarriers. These embodiments are described in
`more detail below.
`
`In some embodiments, multicarrier transmitter 100 (FIG.
`1) and/or multicarrier receiver 200 (TIG. 2) may communi-
`cate over a wideband multicarrier communication channel.
`The wideband channel may comprise one or more multicar-
`rier subchannels. The subchannels may be [requency-divi-
`sion multiplexed(i.e., separated in frequency fromother 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 subchannel may be closely spaced OFDM
`subcarriers. To achieve orthogonality between closely spaced
`i2
`subcarricrs, in some embodiments, the subcarricrs of a par-
`ticular subchannel may have a null at substantially a center
`frequencyof the other subcarriers of that subchannel.
`In some embodiments, multicarrier transmitter 100 (FIG.
`1) and/or multicarrier receiver 200 (FIG. 2) may communi-
`cate with one or more other communicationstations over a 5
`multicarrier communication comprising either a standard-
`throughput channel or a high-throughput communication
`channel.
`In these embodiments,
`the standard-throughput
`channel may comprise one subchannel andthe high-through-
`put channel may comprise a combination of one or more
`subchannels and/or one or more spatial channels associated
`with each subchannel. Spatial channels may be non-orthogo-
`nal channels (i.e., not separated in frequency) associated with
`a particular subchannel
`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. [he modulation assignments for the individual
`subchannel maybe based on the channel characteristics or
`channel conditionsfor that subcarrier, although the scope of
`the inventionis not limited in this respect. In some embodi-
`ments,
`the subcarrier modulation assignments may range
`from zero bits per symbolto up to ten or morebits 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
`phaseshift keying (QPSK), which communicates twobits per
`symbol, 8PSK, which communicates three bits per symbol,
`16-quadrature amplitude modulation (16-QAM), which com-
`municates four bils per symbol, 32-QAM, which communi-
`cates five bits per symbol, 64-QAM,which communicates six
`bits per symbol, 128-QAM,which communicates seven bits
`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 spectrums for the
`multicarricr communication channel may comprise 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 GIlz spectrum may
`include frequencies ranging from approximately 2.3 to 2.5
`GHz,although the scopeofthe invention is not limited in this
`respect, as other frequency spectrumsare also equally suit-
`able.
`In some embodiments, multicarrier transmitter 100 (FIG.
`1) and/or multicarrier receiver 200 (FIG. 2) may bepart of a
`wireless communication device. The wireless communica-
`tion device may, for example, be a personal digital assistant
`(PDA), a laptop or portable computer with wireless commu-
`nication capability, a web tablet, a wireless telephone, a wire-
`less headset, a pager, an instant messaging device, a digital
`camera, an access point or other device thal may receive
`and/or transmit information wirelessly. In some embodi-
`ments, the wireless communication device maytransmit and/
`or receive RF communications in accordance with specific
`communication standards, such as the Institute of Electrical
`and Electronics Engineers (IEEE) standards including IEEE
`802.11 (a), 802.11(b), 802.1 1(g/h) and/or 802.11(n) standards
`for wireless local area networks (WLANs) and/or 802.16
`standards
`for wireless metropolitan
`area
`networks
`(WMANS), although the wireless communication device
`mayalso be suitable to transmit and/or receive communica-
`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 (T1G. 1) and antennas 202 (FIG. 2) may
`comprise directional or omnidirectional antennas, including,
`for example, dipole antennas, monopole antennas,
`loop
`anlennas, microstrip antennasor other type of antennassuil-
`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.,
`802.11a, 802.11g, 802.11 HT, etc.), the scope of the present
`inventionis not limited in this respect. Some embodiments of
`the present invention may be implemented as part of any
`wircless system using multicarricr wireless communication
`channels (e.g., orthogonal frequency-division multiplexing
`(OFDM), discrete mulli-tone modulation (DMT), etc.), such
`as maybe used within, withoutlimitation, a wireless personal
`
`ZTE, Exhibit 1006-0016
`
`ZTE, Exhibit 1006-0016
`
`

`

`US 7,570,696 B2
`
`0
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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 (3G) network, a fourth generation (4G) net-
`work, a universal mobile telephone system (UMTS), and the
`like communication systems.
`Although multicarrier 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 includingdigital signal processors (DSPs),
`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 embodimentsofthe 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
`communicationsignals, althoughthe scope ofthe inventionis
`not limited in this respect.
`i]a
`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 transmil-
`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 asa local
`area network, although the scope of the inventionis not lim-
`ited in this respect.
`In accordance with some embodiment