US007746886B2
`
`a2) United States Patent
`US 7,746,886 B2
`(10) Patent No.:
`
` Hansenet al. (45) Date of Patent: Jun. 29, 2010
`
`
`(54) ASYMMETRICAL MIMO WIRELESS
`COMMUNICATIONS
`
`..... 370/210
`2005/0265225 A1* 12/2005 Mahadevappa etal.
`2006/0093066 Al*
`5/2006 Jeongetal. we. 375/299
`
`(75)
`
`Inventors: Christopher J. Hansen, Sunnyvale, CA
`(US); Jason A. Trachewsky, Menlo
`Park, CA (US); Nambirajan Seshadri,
`Irvine, CA (US); Kelly Brian Cameron,
`Irvine, CA (US); Hau Thien Tran,
`Irvine, CA (US); Ba-Zhong Shen,
`Irvine, CA (US)
`
`(73) Assignee: Broadcom Corporation,Irvine, CA
`(US)
`
`(*) Notice:
`
`Subject to any disclaimer, the term ofthis
`patent is extended or adjusted under 35
`US.C. 154(b) by 1199 days.
`
`(21) Appl. No.: 10/979,368
`
`(22)
`
`Filed:
`
`Nov. 1, 2004
`
`(65)
`
`Prior Publication Data
`
`US 2005/0185575 Al
`
`Aug. 25, 2005
`
`Related U.S. Application Data
`
`(60) Provisional application No. 60/575,920, filed on Jun.
`1, 2004, provisional application No. 60/556,264, filed
`on Mar. 25, 2004, provisional application No. 60/545,
`854, filed on Feb. 19, 2004.
`
`(51)
`
`Int. Cl.
`(2006.01)
`HO4W 76/00
`(52) US. C1. cee ecceesceeeneeeeeeeneeee 370/437; 370/465
`(58) Field of Classification Search ................. 370/437,
`370/465
`See application file for complete search history.
`.
`References Cited
`
`(56)
`
`U.S. PATENT DOCUMENTS
`2002/0193146 Al* 12/2002 Wallace etal. 0.00... 455/562
`2003/0235147 Al* 12/2003 Walton etal. ........0.. 370/204
`
`OTHER PUBLICATIONS
`
`Lam et al., ‘Self-Matching Space-Time Block Codes for Matrix
`Kalman Estimator-Based ML Detector in MIMO Fading Channels’,
`Jul. 2007, IEEE Transactions on Vehicular Technology,vol. 56, Issue
`4, Part 2, pp. 2130-2142.*
`Hollanti et al., ‘Asymmetric Space-Time Block Codes for MIMO
`Systems’, Jul. 2007, Information Theory for Wireless Networks, pp.
`1-5.*
`Khalighiet al., ‘Semi-Blind Channel Estimation Using the EM Algo-
`rithm in Herative MIMO APPDetectors’, Nov. 2006, IEEE Transac-
`tions on Wireless Communications, vol. 5, No. 11, pp. 3165-3173.*
`Sun et al., “Space-Time Precoding for Asymmetric MIMO Chan-
`nels’, 2006, Wireless Communications and Networking Conference,
`pp. 1316-1321.*
`Wong et al.,
`‘List Slab-Sphere Decoding: Efficient High-Perfor-
`mance Decoding for Asymmetric MIMO Antenna Systems’, May/
`Jun. 2005, Vehicular Technology Conference,vol. 1, pp. 697-701.*
`Sumeet Sandhu, “Transmit diversity for MIMO-OFDM’, IEEE 802.
`11-11-03-0847-00-000n, Nov. 2003, pp. 1-11.*
`
`* cited by examiner
`
`Primary Examiner—Melvin Marcelo
`(74) Attorney, Agent, or Firm—Garlick Harrison &
`Markison; Bruce E. Stuckman
`
`(57)
`
`ABSTRACT
`
`A method for asymmetrical MIMO wireless communication
`begins by determining a numberoftransmission antennasfor
`the asymmetrical MIMO wireless communication. The
`method continues by determining a number of reception
`antennas for the asymmetrical MIMO wireless communica-
`tion. The method continues by, when the numberoftransmis-
`sion antennas exceeds the number of reception antennas,
`using spatial time block coding for the asymmetrical MIMO
`wireless communication. The method continues by, when the
`numberoftransmission antennas does not exceed the number
`:
`:
`:
`:
`:
`of reception antennas, using spatial multiplexing for the
`asymmetrical MIMO wireless communication.
`
`20 Claims, 19 Drawing Sheets
`
`Antenna 0
`
`Antenna 1
`
`Antenna 2
`
`Antenna 3
`
`Symbol m
`
`Symbol m+1
`
`Symbol m+2
`
`Symbol m+3
`
`1
`
`SAMSUNG 1078
`SAMSUNG 1078
`SAMSUNG v. SMART MOBILE
`SAMSUNGv. SMART MOBILE
`IPR2022-01004
`IPR2022-01004
`
`1
`
`

`

`U.S. Patent
`
`Jun. 29, 2010
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`US 7,746,886 B2
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`1
`ASYMMETRICAL MIMO WIRELESS
`COMMUNICATIONS
`
`This invention is claiming priority under 35 USC § 119(e)
`to three provisional patent applications: the first is entitled
`WLAN TRANSMIITER
`HAVING HIGH
`DATA
`
`THROUGHPUThavinga filing date of Feb. 19, 2004 and a
`provisionalSer. No. 60/545,854; the second is entitled MUL-
`TIPLE INPUT MULTIPLE OUTPUT WIRELESS LOCAL
`
`
`
`AREA NETWORK COMMUNICATIONShavinga provi-
`sional Ser. No. 60/556,264 anda filing date of Mar. 25, 2004;
`and the third has the sametitle as the present patent applica-
`tion, a provisional Ser. No. 60/575,920, and a provisional
`filing date of Jun. 1, 2004.
`
`BACKGROUNDOF THE INVENTION
`
`1. Technical Field of the Invention
`
`This invention relates generally to wireless communica-
`tion systems and moreparticularly to a transmitter transmit-
`ting at high data rates within such wireless communication
`systems.
`2. Description of Related Art
`Communication systems are known to support wireless
`and wire lined communications between wireless and/or wire
`
`lined communication devices. Such communication systems
`range from national and/or international cellular telephone
`systems to the Internet to point-to-point in-home wireless
`networks. Each type of communication system is con-
`structed, and hence operates, in accordance with one or more
`communication standards. For instance, wireless communi-
`cation systems may operate in accordance with one or more
`standards including, but not limited to, IEEE 802.11, Blue-
`tooth, advanced mobile phone services (AMPS), digital
`AMPS, global system for mobile communications (GSM),
`code division multiple access (CDMA), local multi-point
`distribution systems (LMDS), multi-channel-multi-pointdis-
`tribution systems (MMDS), and/orvariations thereof.
`Dependingonthe type of wireless communication system,
`a wireless communication device, such as a cellular tele-
`phone, two-wayradio, personal digital assistant (PDA), per-
`sonal computer (PC), laptop computer, home entertainment
`equipment, et cetera communicates directly or indirectly with
`other wireless communication devices. For direct communi-
`
`cations (also known as point-to-point communications), the
`participating wireless communication devices tune their
`receivers and transmitters to the same channel or channels
`(e.g., one of the plurality of radio frequency (RF)carriers of
`the wireless communication system) and communicate over
`that channel(s). For indirect wireless communications, each
`wireless communication device communicates directly with
`an associated basestation (e.g., for cellular services) and/or
`an associated access point (e.g., for an in-homeorin-building
`wireless network) via an assigned channel. To complete a
`communication connection between the wireless communi-
`cation devices, the associated base stations and/or associated
`access points communicate with each other directly, via a
`system controller, via the public switch telephone network,
`via the Internet, and/or via some other wide area network.
`For each wireless communication device to participate in
`wireless communications, it includes a built-in radio trans-
`ceiver(i.e., receiver and transmitter) or is coupled to an asso-
`ciated radio transceiver (e.g., a station for in-home and/or
`in-building wireless communication networks, RF modem,
`etc.). As is known, the receiver is coupled to the antenna and
`includes a low noise amplifier, one or more intermediate
`frequencystages, a filtering stage, and a data recovery stage.
`
`2
`The low noise amplifier receives inbound RFsignals via the
`antenna and amplifies then. The one or more intermediate
`frequency stages mix the amplified RF signals with one or
`morelocal oscillations to convert the amplified RF signal into
`basebandsignals or intermediate frequency (IF) signals. The
`filtering stage filters the basebandsignals or the IF signals to
`attenuate unwanted out of band signals to producefiltered
`signals. The data recovery stage recovers raw data from the
`filtered signals in accordance with the particular wireless
`communication standard.
`Asis also known, the transmitter includes a data modula-
`tion stage, one or more intermediate frequency stages, and a
`poweramplifier. The data modulation stage converts raw data
`into basebandsignals in accordance with a particular wireless
`communication standard. The one or more intermediate fre-
`quency stages mix the baseband signals with one or more
`local oscillations to produce RF signals. The power amplifier
`amplifies the RF signals prior to transmission via an antenna.
`Typically, the transmitter will include one antenna for
`transmitting the RF signals, which are received by a single
`antenna, or multiple antennas, of a receiver. When the
`receiver includes two or more antennas, the receiver will
`select one of them to receive the incoming RFsignals. In this
`instance, the wireless communication between the transmit-
`ter and receiver is a single-output-single-input (SISO) com-
`munication, even if the receiver includes multiple antennas
`that are used as diversity antennas(1.e., selecting one of them
`to receive the incoming RFsignals). For SISO wireless com-
`munications, a transceiver includes one transmitter and one
`receiver. Currently, most wireless local area networks
`(WLAN)that are IEEE 802.11, 802.11a, 802,11b, or 802.11¢
`employ SISO wireless communications.
`Other types of wireless communications include single-
`input-multiple-output (SIMO), multiple-input-single-output
`(MISO), and multiple-input-multiple-output (MIMO). In a
`SIMO wireless communication, a single transmitter pro-
`cesses data into radio frequencysignals that are transmitted to
`a receiver. The receiver includes two or more antennas and
`
`twoor more receiver paths. Each of the antennasreceives the
`RFsignals and provides them to a corresponding receiver
`path (e.g., LNA, down conversion module,filters, and ADCs).
`Eachofthe receiver paths processes the received RF signals
`to producedigital signals, which are combined andthen pro-
`cessed to recapture the transmitted data.
`For a multiple-input-single-output (MISO) wireless com-
`munication, the transmitter includes two or more transmis-
`sion paths(e.g., digital to analog converter,filters, up-conver-
`sion module, and a power amplifier) that each converts a
`corresponding portion of baseband signals into RF signals,
`which are transmitted via corresponding antennas to a
`receiver. The receiver includes a single receiver path that
`receives the multiple RF signals from the transmitter. In this
`instance, the receiver uses beam forming to combine the
`multiple RF signals into one signal for processing.
`For a multiple-input-multiple-output (MIMO) wireless
`communication, the transmitter and receiver each include
`multiple paths. In such a communication,the transmitter par-
`allel processes data using a spatial and time encoding func-
`tion to produce two or more streamsof data. The transmitter
`includes multiple transmission paths to convert each stream
`of data into multiple RF signals. The receiver receives the
`multiple RF signals via multiple receiver paths that recapture
`the streams of data utilizing a spatial and time decoding
`function. The recaptured streams of data are combined and
`subsequently processed to recoverthe original data.
`With the various types of wireless communications(e.g.,
`SISO, MISO, SIMO, and MIMO),it would be desirable to use
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`US 7,746,886 B2
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`one or more types of wireless communications to enhance
`data throughput within a WLAN.For example, high data rates
`can be achieved with MIMO communications in comparison
`to SISO communications. However, most WLAN include
`legacy wireless communication devices(i.e., devices that are
`compliant with an older version of a wireless communication
`standard. As such, a transmitter capable of MIMO wireless
`communications should also be backward compatible with
`legacy devices to function in a majority of existing WLANs.
`Further, asymmetric MIMOis any M transmit antenna, N
`receive antenna communication system in which M !=N. The
`case of M<N doesnot need to be considered by the 802.11n
`standard. However, the practical case of M>N does. This case
`may happen when an access point (AP) with many antennas
`attempts to send frames to devices with only two(e.g. an old
`laptop PC). This case mayalso be relevant to certain broad-
`cast/multicast Greenfield frame transmissions, e.g. beacons.
`Therefore, a need exists for a WLAN transmitter that is
`capable ofhigh data throughput, is backward compatible with
`legacy devices, and supports asymmetrical MIMOtransmis-
`sions.
`
`BRIEF SUMMARY OF THE INVENTION
`
`The asymmetrical wireless communication ofthe present
`invention substantially meets these needs and others. In one
`embodiment, a method for asymmetrical MIMO wireless
`communication begins by determining a numberoftransmis-
`sion antennasfor the asymmetrical MIMO wireless commu-
`nication. The method continues by determining whether the
`asymmetric MIMOwireless communication will use spatial
`multiplexing or space-time block coding based on the number
`of transmission antennas. The method continues, for spatial
`multiplexing, by providing different constellation points for
`transmission on cach ofthe numberoftransmission antennas.
`
`4
`FIG. 3 is a schematic block diagram of an RF transmitter in
`accordance with the present invention;
`FIG.4 is a schematic block diagram of an RF receiver in
`accordance with the present invention;
`FIG. 5 is a logic diagram of a method for baseband pro-
`cessing of data in accordance with the present invention;
`FIG.6 is a logic diagram of a methodthat further defines
`Step 120 of FIG. 5.
`FIGS. 7-9 illustrate logic diagrams of various embodi-
`ments for encoding the scrambled data in accordance with the
`present invention;
`FIGS. 10A and 10B are a schematic block diagram of a
`radio transmitter in accordance with the present invention;
`FIGS. 11A and 11B are a schematic block diagram of a
`radio receiver in accordance with the present invention;
`FIG. 12 is a schematic block diagram of a channel encoder
`in accordance with the present invention;
`FIG. 13 is a schematic block diagram of a constituent
`encoderin accordance with the present invention;
`FIG. 14 is a schematic block diagram of an alternate
`embodimentof a constituent encoder in accordance with the
`
`present invention;
`FIG. 15 is a schematic block diagram of a rate 74 encoder
`in accordance with the present invention;
`FIG. 16is a schematic block diagram ofa puncture encoder
`in accordance with the present invention;
`FIG. 17 is a schematic block diagram of another embodi-
`ment of a puncture encoder in accordance with the present
`invention;
`FIG. 18 is a schematic block diagram of a low density
`parity check encoder in accordance with the present inven-
`tion;
`FIG. 19 is an illustration of an interleaver in accordance
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`with the present invention;
`FIG. 20 is a diagram of an example asymmetric commu-
`The method continues by, for space-time block coding: dur-
`nication in accordance with the present invention;
`ing a first time interval: providing, for transmission onafirst
`FIG.21 is a diagram of space-time block coding in accor-
`one of the numberof transmission antennas, a first constella-
`dance with the present invention;
`tion point, and providing, for transmission on a second one of
`FIG. 22 is a diagram oftwo antenna asymmetrical wireless
`the numberof transmission antennas, a second constellation
`communication in accordance with the present invention;
`point. The method continues by, during a second timeinter-
`FIG. 23 is a diagram of three antenna asymmetrical wire-
`val: providing, for transmission onthefirst one ofthe number
`less communication in accordance with the present invention;
`oftransmission antennas, an inverse complex conjugate ofthe
`FIG.24 is another diagram of three antenna asymmetrical
`second constellation point, and providing, for transmission
`wireless communication in accordance with the present
`on the second one of the numberof transmission antennas, a
`invention;
`complex conjugate of the second constellation point.
`FIG. 25 is a diagram of four antenna asymmetrical wireless
`In another embodiment, a method for asymmetrical MIMO
`communication in accordancewith the present invention; and
`wireless communication begins by determining a number of
`FIG. 26 is another diagram of four antenna asymmetrical
`transmission antennas for the asymmetrical MIMO wireless
`wireless communication in accordance with the present
`invention;
`communication. The method continues by determining a
`number of reception antennas for the asymmetrical MIMO
`wireless communication. The method continues by, when the
`number of transmission antennas exceeds the number of
`reception antennas, using spatial time block coding for the
`asymmetrical MIMO wireless communication. The method
`continues by, when the numberoftransmission antennas does
`not exceed the number of reception antennas, using spatial
`multiplexing for the asymmetrical MIMO wireless commu-
`nication.
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`DETAILED DESCRIPTION OF THE INVENTION
`
`FIG. 1 is a schematic block diagram illustrating a commu-
`nication system 10 that includes a plurality of base stations
`and/or access points 12-16, a plurality of wireless communi-
`cation devices 18-32 and a network hardware component34.
`The wireless communication devices 18-32 may be laptop
`host computers 18 and 26, personaldigital assistant hosts 20
`and 30, personal computer hosts 24 and 32 and/or cellular
`telephone hosts 22 and 28. The details of the wireless com-
`munication devices will be described in greater detail with
`reference to FIG. 2.
`
`BRIEF DESCRIPTION OF THE SEVERAL
`VIEWS OF THE DRAWINGS
`
`FIG.1 is a schematic block diagram of a wireless commu-
`nication system in accordance with the present invention;
`FIG. 2 is a schematic block diagram of a wireless commu-
`nication device in accordance with the present invention;
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`The base stations or access points 12-16 are operably
`coupled to the network hardware 34 via local area network
`connections 36, 38 and 40. The network hardware 34, which
`maybea router, switch, bridge, modem, system controller,et
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`US 7,746,886 B2
`
`5
`cetera provides a wide area network connection 42 for the
`communication system 10. Each ofthe basestationsor access
`points 12-16 has an associated antenna or antenna array to
`communicate with the wireless communication devicesin its
`
`area. Typically, the wireless communication devices register
`with a particular basestation or access point 12-14 to receive
`services from the communication system 10. For direct con-
`nections(1.e., point-to-point communications), wireless com-
`munication devices communicate directly via an allocated
`channel.
`Typically, base stations are used for cellular telephone
`systems and like-type systems, while access points are used
`for in-homeor in-building wireless networks. Regardless of
`the particular type of communication system, each wireless
`communication device includes a built-in radio and/or is
`coupledto a radio. The radio includes a highly linear amplifier
`and/or programmable multi-stage amplifier as disclosed
`herein to enhance performance, reduce costs, reduce size,
`and/or enhance broadband applications.
`FIG. 2 is a schematic block diagram illustrating a wireless
`communication device that includes the host device 18-32
`
`and an associated radio 60. For cellular telephone hosts, the
`radio 60 is a built-in component. For personal digital assis-
`tants hosts, laptop hosts, and/or personal computer hosts, the
`radio 60 maybe built-in or an externally coupled component.
`Asillustrated, the host device 18-32 includes a processing
`module 50, memory 52, radio interface 54, input interface 58
`and output interface 56. The processing module 50 and
`memory 52 execute the corresponding instructions that are
`typically done by the host device. For example, for a cellular
`telephonehost device, the processing module 50 performsthe
`corresponding communication functions in accordance with
`a particular cellular telephone standard.
`Theradio interface 54 allowsdata to be received from and
`sent to the radio 60. For data received fromthe radio 60 (e.g.,
`inbounddata), the radio interface 54 provides the data to the
`processing module 50 for further processing and/or routing to
`the output interface 56. The output interface 56 provides
`connectivity to an output display device such as a display,
`monitor, speakers, et cetera such that the received data may be
`displayed. The radio interface 54 also provides data from the
`processing module 50to the radio 60. The processing module
`50 may receive the outbound data from an input device such
`as a keyboard, keypad, microphone, et cetera via the input
`interface 58 or generate the data itself. For data received via
`the input interface 58, the processing module 50 may perform
`a correspondinghostfunction on the data and/or route it to the
`radio 60 via the radio interface 54.
`Radio 60 includesa host interface 62, a baseband process-
`ing module 64, memory 66, a plurality of radio frequency
`(RF) transmitters 68-72, a transmit/receive (T/R) module 74,
`a plurality of antennas 82-86, a plurality of RF receivers
`76-80, and a local oscillation module 100. The baseband
`processing module 64,
`in combination with operational
`instructions stored in memory 66, execute digital receiver
`functions and digital transmitter functions, respectively. The
`digital receiver functions, as will be described in greater detail
`with reference to FIG. 11B, include, but are not limited to,
`digital
`intermediate frequency to baseband conversion,
`demodulation, constellation demapping, decoding, de-inter-
`leaving, fast Fourier transform, cyclic prefix removal, space
`and time decoding, and/or descrambling. The digital trans-
`mitter functions, as will be described in greater detail with
`reference to FIGS. 5-19,
`include, but are not limited to,
`scrambling, encoding, interleaving, constellation mapping,
`modulation,inverse fast Fourier transform, cyclic prefix addi-
`tion, space and time encoding, and/or digital baseband to IF
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`conversion. The baseband processing modules 64 may be
`implemented using one or more processing devices. Such a
`processing device may be a microprocessor, micro-control-
`ler, digital signal processor, microcomputer, central process-
`ing unit, field programmable gate array, programmable logic
`device, state machine,logic circuitry, analog circuitry, digital
`circuitry, and/or any device that manipulates signals (analog
`and/or digital) based on operational
`instructions. The
`memory 66 may be a single memory deviceor a plurality of
`memory devices. Such amemory device may be a read-only
`memory, random access memory, volatile memory, non-vola-
`tile memory, static memory, dynamic memory,flash memory,
`and/or any device that stores digital information. Note that
`whenthe processing module 64 implements one or more ofits
`functions via a state machine, analog circuitry, digital cir-
`cuitry, and/or logic circuitry, the memorystoring the corre-
`sponding operational instructions is embedded with the cir-
`cuitry comprising the state machine, analog circuitry, digital
`circuitry, and/or logic circuitry.
`In operation, the radio 60 receives outbound data 88 from
`the host device via the host interface 62. The basebandpro-
`cessing module 64 receives the outbound data 88 and, based
`on a modeselection signal 102, produces one or more out-
`bound symbolstreams 90. The modeselection signal 102 will
`indicate a particular modeas are illustrated in the modeselec-
`tion tables, which appearat the end ofthe detailed discussion.
`For example, the modeselection signal 102, with reference to
`table 1 may indicate a frequency bandof 2.4 GHz, a channel
`bandwidth of 20 or 22 MHz and a maximum bit rate of 54
`
`the mode
`megabits-per-second. In this general category,
`selection signal will further indicate a particular rate ranging
`from 1 megabit-per-second to 54 megabits-per-second. In
`addition, the modeselection signal will indicate a particular
`type of modulation, which includes, but is not limited to,
`Barker Code Modulation, BPSK, QPSK, CCK, 16 QAM
`and/or 64 QAM.Asis furtherillustratedin table 1, a code rate
`is supplied as well as number of coded bits per subcarrier
`(NBPSC), coded bits per OFDM symbol (NCBPS), data bits
`per OFDM symbol (NDBPS).
`The modeselection signal may also indicate a particular
`channelization for the corresponding mode which for the
`information intable1 is illustrated in table 2. As shown,table
`2 includes a channel number and corresponding centerfre-
`quency. The modeselect signal may further indicate a power
`spectral density mask value whichfor table 1 is illustrated in
`table 3. The mode select signal may alternatively indicate
`rates within table 4 that has a 5 GHz frequency band, 20 MHz
`channel bandwidth and a maximum bit rate of 54 megabits-
`per-second.If this is the particular modeselect, the channel-
`ization is illustrated in table 5. As a further alternative, the
`modeselect signal 102 may indicate a 2.4 GHz frequency
`band, 20 MHz channels and a maximum bit rate of 192
`megabits-per-secondasillustrated in table 6. In table 6, a
`number of antennas may be utilized to achieve the higher
`bandwidths. In this instance, the mode select would further
`indicate the numberof antennasto be utilized. Table 7 illus-
`
`trates the channelization for the set-up of table 6. Table 8
`illustrates yet another mode option wherethe frequency band
`is 2.4 GHz,the channel bandwidth is 20 MHz andthe maxi-
`mum bit rate is 192 megabits-per-second. The corresponding
`table 8 includes various bit rates ranging from 12 megabits-
`per-secondto 216 megabits-per-secondutilizing 2-4 antennas
`and a spatial time encoding rate as indicated. Table 9 illus-
`trates the channelization for table 8. The modeselect signal
`102 mayfurther indicate a particular operating modeas illus-
`trated in table 10, which corresponds to a 5 GHz frequency
`band having 40 MHz frequency band having 40 MHz chan-
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`US 7,746,886 B2
`
`7
`nels and a maximumbit rate of 486 megabits-per-second. As
`shownin table 10, the bit rate may range from 13.5 megabits-
`per-secondto 486 megabits-per-secondutilizing 1-4 antennas
`and a corresponding spatial time code rate. Table 10 further
`illustrates a particular modulation scheme code rate and
`NBPSCvalues. Table 11 provides the powerspectral density
`maskfor table 10 and table 12 provides the channelization for
`table 10.
`The baseband processing module 64, based on the mode
`selection signal 102 producesthe one or more outbound sym-
`bol streams 90, as will be further described with reference to
`FIGS. 5-9 from the output data 88. For example, if the mode
`selection signal 102 indicates that a single transmit antenna is
`being utilized for the particular modethat has been selected,
`the baseband processing module 64 will produce a single
`outbound symbolstream 90. Alternatively, if the mode select
`signal indicates 2, 3 or 4 antennas, the baseband processing
`module 64 will produce 2, 3 or 4 outbound symbolstreams 90
`corresponding to the numberof antennasfrom the output data
`88.
`
`Depending on the number of outbound streams 90 pro-
`duced by the baseband module 64, a corresponding number of
`the RF transmitters 68-72 will be enabled to convert the
`
`outbound symbol streams 90 into outbound RF signals 92.
`The implementation of the RF transmitters 68-72 will be
`further described with reference to FIG. 3. The transmit/
`
`receive module 74 receives the outbound RF signals 92 and
`provides each outbound RFsignalto a corresponding antenna