`a2) Patent Application Publication 10) Pub. No.: US 2006/0098568 A1
`
` Ohet al. (43) Pub. Date: May11, 2006
`
`
`US 20060098568A1
`
`(54) METHOD FOR SUPPORTING VARIOUS
`MULTI-ANTENNA SCHEMES IN BWA
`
`(30)
`
`Foreign Application Priority Data
`
`SYSTEM USING MULTIPLE ANTENNAS
`
`Nov. 9, 2004
`
`(KR) .eeeeccescsescseesssceneeeneerees 91120/2004
`
`(75)
`
`Inventors: Jeong-Tae Oh, Yongin-si (KR); Won-II
`Roh, Yongin-si (KR); Kyun-Byoung
`Ko, Hwaseong-si (KR); Jae-Ho Jeon,
`Seongnam-si (KR); Sung-Ryul Yun,
`Suwon-si (KR); Hong-Sil Jeong,
`Suwon-si (KR); Chan-Byoung Chae,
`Seoul (KR); Seung-Joo Maeng,
`Seongnam-si (KR)
`Correspondence Address:
`DILWORTH & BARRESE, LLP
`333 EARLE OVINGTON BLVD.
`UNIONDALE,NY 11553 (US)
`
`(73) Assignee: SAMSUNG ELECTRONICS CO.,
`LTD., Suwon-si (KR)
`
`(21) Appl. No.:
`
`11/268,893
`
`(22)
`
`Filed:
`
`Nov. 8, 2005
`
`Publication Classification
`
`(51)
`
`Int. Cl.
`(2006.01)
`HO04] 11/00
`(52) US. Ce ececscesenceseressesecesencenecesnsseessenseneenenee 370/206
`(57)
`ABSTRACT
`Disclosed is a method for using various multiple antenna
`schemes in a baseband wireless access system is provided.
`According to the method, a downlink MAP message is
`constructed in order to support various multiple antenna
`schemes based on a multiple-input multiple output (MIMO),
`which is one of the multiple antenna schemes, so that
`compatibility with exiting MIMO technology having no
`MIMOfeedback can be achieved and overhead occurring in
`transmission of an MAP information element can be
`reduced. Further, it is possible to efficiently support spatial
`multiplexing technology capable of transmitting multiple
`layers having different modulation and coding in a MIMO
`system.
`
`105
`1068.
`107
`
`>
`
`
`
`carrier
`101
`102
`103
`
`
`
`Precoding
`STG
`mapper
`
`
`
`Encoder
`matrix
`
`
`
`of
`
`S/P W
`
`
`APPLE 1022
`APPLE 1022
`
`
`
`Patent Application Publication May 11,2006 Sheet 1 of 3
`
`US 2006/0098568 A1
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`US 2006/0098568 A1
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`Patent Application Publication May 11,2006 Sheet 3 of 3
`
`US 2006/0098568 Al
`
` 4:(HEonly).
` L 3{HEonly)-
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`L=2(HEonly) I(TDorVEonly)
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`US 2006/0098568 Al
`
`May 11, 2006
`
`METHOD FOR SUPPORTING VARIOUS
`MULTI-ANTENNA SCHEMES IN BWA SYSTEM
`USING MULTIPLE ANTENNAS
`
`PRIORITY
`
`[0009] The MIMOtechnology mayalso be classified into
`a closed-loop scheme,
`in which channel
`information is
`fedback from a receiver to a transmitter, and an open loop
`scheme, in which channel information is not fedback from
`a receiver to a transmitter.
`
`[0001] This application claims priority to an application
`entitled “Method for Supporting Various Multi-antenna
`Schemes in BWA System Using Multiple Antenna”filed in
`the Korean Intellectual Property Office on Nov. 9, 2004 and
`assigned Serial No. 2004-91120, the contents of which are
`incorporated herein by reference.
`
`standard documents
`[0010] Referring to the current
`802.16-REVd&D5, REVe/D5-2004 of the Institute of Elec-
`trical and Electronics Engineers (IEEE) 802.16e standard,
`only a scheme for supporting the MIMO technology using
`the open loop scheme has been proposed.
`SUMMARY OF THE INVENTION
`
`BACKGROUNDOF THE INVENTION
`
`[0002]
`
`1. Field of the Invention
`
`[0003] The present invention relates to a Broadband Wire-
`less Access (BWA) system, and more particularly to a
`method for supporting various multiple antenna schemes in
`a system using an Orthogonal Frequency Division Multiple
`Access (OFDMA)scheme.
`
`[0004]
`
`2. Description of the Related Art
`
`In the current wireless mobile communication sys-
`[0005]
`tem, extensive research is being conducted into a high
`quality multimedia service capable of transmitting mass
`storage data at a high speed. Different from wire channel
`environments, wireless channel environments are subject to
`a distortion of the actual transmission signals due to various
`factors such as multi-path interference, shadowing, wave
`attenuation, time-varying noise and interference. Fading due
`to the multi-path interference is closely related to the mobil-
`ity of a reflector or a user terminal. Accordingly, the actual
`transmission signals are mixed with interference signals and
`mixed signals are received. Because the received signals
`already represent a serious distortion of the actual transmis-
`sion signals, the entire performance of a mobile communi-
`cation system may deteriorate.
`
`[0006] Fading mayalso distort the amplitude and phase of
`the received signals, and may become a main factor that
`disrupts the high speed data communication in wireless
`channel environments. Therefore, extensive research is
`being conducted in order to solve the fading problem. In
`order to transmit data at a high speed in a mobile commu-
`nication system, it is necessary to minimize loss and any
`user-by-user interference resulting from the characteristics
`of a mobile communication channel. One of the technolo-
`gies proposedin order to solve the afore-described problems
`is a Multiple Input Multiple Output (MIMO) technology.
`
`[0007] The MIMOtechnology may beclassified accord-
`ing to the data transmission schemes used and whether the
`channel information is fedback.
`
`[0008] First, the MIMO technology maybeclassified into
`a Spatial Multiplexing (SM) technique and a Spatial Diver-
`sity (SD) technique according to the data transmission
`schemes. The SM technique is a technique for simulta-
`neously transmitting different data by means of multiple
`antennas in a transmitter and a receiver, thereby transmitting
`data at a higher speed without increasing the bandwidth of
`the system. The SD technique is a technique for transmitting
`the identical data through multiple transmit (Tx) antennas,
`thereby achieving the Transmit Diversity (TD).
`
`[0011] Accordingly, the present invention has been made
`to solve at least the above-mentioned problems occurring in
`the prior art, and it is an object of the present invention to
`provide a method for supporting various multiple antenna
`schemes based on MIMO technology in a BWA system
`using multiple antennas.
`
`It is another object of the present invention to
`[0012]
`provide a method for supporting various multiple antenna
`schemes by constructing an MAP message for classifying
`MIMOtechnology in a BWA system using multiple anten-
`nas.
`
`It is a further object of the present invention to
`[0013]
`provide a method for supporting various multiple antenna
`schemes by constructing a downlink MAP message for
`efficiently providing multiple antenna technology, precoding
`or antenna grouping technology, antenna selection technol-
`ogy, etc., which have feedback from a mobile station.
`
`In order to accomplish the aforementioned objects,
`[0014]
`according to one aspect of the present, there is provided a
`method for supporting various Multiple Input Multiple Out-
`put (MIMO)and precoding technologies in a Broadband
`Wireless Access (BWA) system employing an antenna tech-
`nique of a MIMOscheme, the method including configuring
`a downlink MAP message that includes basic information
`fields for indicating the MIMOtechnology and information
`fields for indicating various precoding technologies; and
`applying the MIMO technology to a mobile station by
`means of the downlink MAP message.
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`[0015] The above and other objects, features and advan-
`tages of the present invention will be more apparent from the
`following detailed description taken in conjunction with the
`accompanying drawings, in which:
`
`FIG.1 is a block diagram illustrating the construc-
`[0016]
`tion of a transmitter, which includes a single encoder and a
`single modulator, capable of performing precoding by
`means of feedback information received from a mobile
`station ina BWA system according to an embodimentof the
`present invention;
`
`FIG.2 is a block diagram illustrating the construc-
`[0017]
`tion of a transmitter, which includes a plurality of encoders
`and modulators, capable of performing preceding by means
`of feedback information received from a mobile station in a
`
`BWA system according to another embodiment of the
`present invention; and
`
`[0018] FIG. 3 is a diagram illustrating available technol-
`ogy according to the numberof layers and streams according
`to an embodimentof the present invention.
`
`
`
`US 2006/0098568 Al
`
`May 11, 2006
`
`DETAILED DESCRIPTION OF THE
`PREFERRED EMBODIMENT
`
`[0019] Hereinafter, preferred embodiments according to
`the present invention will be described with reference to the
`accompanying drawings. In the below description, many
`particular items, such as detailed elements, are shown, but
`these are provided for helping the general understanding of
`the present invention, and it is apparentto those skilled in the
`art that the particular items can be modified or varied within
`the scope of the present invention.
`
`[0020] The present invention provides a methodfor using
`various Multiple Input Multiple Output (MIMO) schemesin
`a Broadband Wireless Access (BWA) communication sys-
`tem using multiple antennas. Particularly, the present inven-
`tion proposes a new downlink (DL)-MAP messagein order
`to use a closed-loop MIMO scheme in a BWA communica-
`tion system. The new DL-MAP messageprovides a method
`for selecting a transmission matrix corresponding to both the
`numberof layers determined by the number of modulators
`and the number Mtof streams output from a Space Time
`Coding (STC) encoder. The STC encoder can be realized by
`a serial-to-parallel (S/P) converter. The transmission matrix
`has already been defined the IEEE 802.16 standard accord-
`ing to a transmit diversity scheme, a vertical encoding
`scheme and a horizontal encoding scheme.
`
`[0021] When MIMOtechnology using the new DL-MAP
`message is applied to a BWA communication system, it is
`possible to make the closed-loop MIMOtechnology using
`the Channel Quality Information (CQI) fedback from a
`mobile station, 1.e., a receiver, compatible with an exiting
`open loop MIMO technology having no feedback of the
`CQI. When the closed-loop MIMOtechnologyis used,it is
`possible to perform a precoding.
`
`FIG.1 is a block diagram illustrating the construc-
`[0022]
`tion of a transmitter, which includes a single encoder and a
`single modulator, capable of performing precoding by
`means of feedback information received from a mobile
`
`station ina BWA system according to an embodimentof the
`present invention.
`
`[0023] Referring to FIG. 1, the transmitter includes an
`encoder 102 for performing coding for data 101 to be
`transmitted, a modulator 103 for mapping the coded data on
`a complex plane, an STC encoder 104 for applying basic
`MIMOtechnology to the modulated data, and a precoding
`block 105 for performing precoding for Mt number of
`streams received from the STC encoder 104. The precoding
`block 105 applies MIMO technology by using the CQI
`fedback from a mobile station. Further,
`the transmitter
`includes a sub-carrier mapper 106 for mapping a symbol
`received from the precoding block 105, and an Inverse Fast
`Fourier Transform (IFFT) unit 107 for transforming the
`mapped symbol
`into an Orthogonal Frequency Division
`Multiple Access (OFDMA) symbol.
`
`[0024] Because the transmitter includes one coder 102 and
`one modulator 103 as described above, the numberoflayers
`becomesone (L=1) and the STC encoder 104 outputs the Mt
`numberof streams. Herein, MIMO technology for causing
`the Mt numberof streams to acquire a diversity gain for
`commontransmission signals correspondsto transmit diver-
`sity technology. Further, MIMOtechnology for causing the
`Mt numberof streams to acquire a gain for two or more
`
`separate transmission signals in view of a data rate will be
`referred to Vertical Encoding (VE) Spatial Multiplexing
`(SM) technology.
`
`[0025] The preceding block 105 receives the Mt number
`of streams and performs an MtxNt matrix operation. The Nt
`represents the number of transmit antennas.
`
`construction as
`transmitter having the
`[0026] The
`described above receives channel feedback information and
`
`generates a matrix value of the precoding block 105, thereby
`operating by applying various MIMOalgorithms such as
`feedback precoding (e.g., SVD precoding, beamforming
`preceding, etc), antenna grouping precoding, and antenna
`selection preceding.
`
`[0027] The STC encoder 104 receives one input sequence
`so as to generate the Mt numberof streams. When beam-
`forming-precoding technology is applied, the STC encoder
`104 can output the Mt numberof streams without perform-
`ing STC encoding.
`
`FIG.2 is a block diagram illustrating the construc-
`[0028]
`tion of a transmitter, which includes a plurality of encoders
`and modulators, capable of performing precoding by means
`of feedback information received from a mobile station in a
`
`BWA system according to another embodiment of the
`present invention.
`
`the transmitter includes a
`[0029] Referring to FIG. 2,
`plurality of encoders 202a to 202” and modulators 203a to
`203”. Because the functions of the encoder and the modu-
`
`lator have already been described with reference to FIG.1,
`further detailed description will be omitted.
`
`[0030] Herein, MIMOtransmission technology applied to
`the transmitter having a plurality of layers will be referred to
`as a Horizontal Encoding (HE) spatial multiplexing tech-
`nology.
`
`[0031] The STC encoder 204 receives L number of input
`sequences so as to generate Mt numberof streams. When
`beamforming-precoding technology is applied,
`the STC
`encoder 204 can output the Mt numberof streams without
`performing STC encoding.
`
`[0032] FIG. 3 is a diagram illustrating a scheme for
`applying a transmission matrix according to the numberof
`layers and streams in a BWA communication system accord-
`ing to an embodimentofthe present invention.
`
`[0033] Referring to FIG. 3, A, B and C represent trans-
`mission matrices. Each of the STC encoders 104 and 204
`
`selects one transmission matrix according to the number of
`layers and streams in FIG. 3,
`thereby performing STC
`encoding. In the transmission matrix, a row index coincides
`with the number of antennas and a column index coincides
`with an OFDMA symboltime.
`
`[0034] Equations 1 and 2 below represent sequential input
`symbol matrices of the STC encoders 104 and 204 of
`transmit diversity and spatial multiplexing when the Mtis 2.
`
`=
`
`Auten)
`
`-S3 |
`Si,
`ont) ' Sy
`
`Wd)
`
`
`
`US 2006/0098568 Al
`
`May 11, 2006
`
`-continued
`
`TABLE 1-continued
`
`Sy
`
`Comt=2) = I:2
`
`Q)
`
`Syntax
`
`Size
`(bits) Notes
`
`4
`2
`
`2
`
`[0035] Equations 3 to 5 below represent sequential input
`symbol matrices of the STC encoders 104 and 204 of the
`transmit diversity, a hybrid of the transmit diversity and the
`spatial multiplexing, and the spatial multiplexing when the
`Mtis 3.
`
`Length
`MIMO_Type
`
`Num_layer
`
`®)
`
`Length of the IE in Byte
`Type of MIMO Mode
`00 = Open-loop
`01 = Antenna Grouping
`10 = antenna Selecting
`11 = Closed-loop
`Precoding
`Numberof Multiple
`coding/modulation layers
`00 = 1 layer
`0
`5, -3 0
`O1 = 2 layers
`-Sj
`Aa) =| 8)
`Si
`S35
`10 = 3 layers
`11 =4layers
`0
`Sy
`SS
`Mt
`2
`Indicate number of STC
`output streams
`00 = 1 stream
`@
`-Si
`Si S$ Ss
`01 =2streams
`Bos) = |S)
`-S$ 53-5}
`10 =3 streams
`11 =4 streams
`S Sf
`Se
`St
`
`(5)
`Sy
`Comt=3y =|52
`[0038] Table 2 below represents a message field subse-
`S3
`quent to Table 1.
`
`[0036] Equations 6 to 8 below represent sequential input
`symbol matrices of the STC encoders 104 and 204 of the
`transmit diversity, a hybrid of the transmit diversity and the
`spatial multiplexing, and spatial multiplexing when the Mt
`is 4.
`
` 0
`
`
`S,;
`Sy
`9
`0
`
`S,
`
`-S3
`St
`9
`0
`
`0
`0
`0
`0
`gs, 54
`Sy
`St
`
`-SE Ss
`
`-S%
`
`Ame9=|
`
`ED)
`
`aM
`
`83 Sy Sy
`Sy
`Sh
`Sg
`
`-S3
`Se
`
`St
`So
`Cimt=4) = 53
`Sq
`
`(6)
`
`(7)
`
`(8)
`
`TABLE 2
`
`Mode_Change
`if (Mode_Change = = 1){
`
`if (MIMO_Type = = 00or11){
`if (MIMO_Type = = 11){
`Precoding Index}
`
`Matrix Indicator }
`if (MIMO_Type = = 01){
`
`Antenna Grouping Index}
`
`If (MIMO_Type = = 10){
`Antenna Selection Index}
`
`for (j=1;j<Num_layer; j++){
`
`If (H-ARQ Mode=CTC
`Incremental Redundancy) {
`Nep}
`elseif(H-ARQ Mode=Generic
`Chase)}DIUC
`}
`
`1
`
`Indicates Change of MIMO
`mode 0 = No change
`from previous
`allocation
`1 = Change of MIMO mode
`
`6
`
`2
`
`Indicates the index of precoding
`Matrix Sec8.4.8.3.6
`Indicates open-loop matrix (Sec
`8.4.8.3)
`00 = Matrix
`A(Transmit Diversity)
`01 = Matrix B
`(Hybrid scheme
`Allocation only for 3 and 4
`antennas)
`10 = Matrix C(Pure Spatial
`Multiplexing)
`11 = Reserved
`4 Indicates the index of antenna
`grouping Sec 8.4.8.3.4 and
`8.4.8.3.5
`
`4 Indicates the index of antenna
`selection Sec 8.4.8.3.4 and
`8.4.8.3.5
`
`This loop specifies the Nep for
`layers 2 and above
`when required
`for STC.
`The same Nsch
`and RCID applied
`for each layer
`4 H-ARQ Modeis specified in the
`H-ARQ Compact_DL-MAP IE
`format for Switch H-ARQ Mode
`
`to 3 below represent data formats of a
`[0037] Tables 1
`MIMO-Compact_DL-MAP message proposed as one
`example in order to efficiently provide all MIMO-based
`technologies in a BWA system according to an embodiment
`of the present invention.
`
`Syntax
`
`TABLE1
`
`Size
`(bits) Notes
`
`MIMO_Compact_DL-MAP_IE () {
`Compact_DL-MAP Type
`DL-MAP Sub-type
`
`3
`5
`
`Type =7
`MIMO = 0x01
`
`
`
`US 2006/0098568 Al
`
`May 11, 2006
`
`TABLE2-continued
`
`if(CQICH indicator = = 1){
`
`Allocation Index
`
`}
`
`6
`
`CQICH indicator comes
`from the precoding
`Compact DL-MAP IE
`Index to CQICHassigned to this
`layer, For the multi-layer MIMO
`transmission,
`the feedback type for
`this CQICH and that of the
`precoding Compact DL-MAPIE
`shall be 000.
`
`[0039] Table 3 below represents a message field subse-
`quent to Table 2.
`
`TABLE3
`
`CQICH_Num
`
`for (j=1;j<CQICH_NUMGj++){
`CQI Feedback type
`
`Period(p)
`
`for (i=0;i<CQICH_Num;i++){
`Allocation index
`
`}
`
`}
`padding
`
`2
`
`3
`
`2
`
`5
`
`Total number of CQICHs
`assigned to this SS is
`(CQICH_Num + 1)
`00 = 1 CQICH
`01 = 2 CQICH
`10 = 3 CQICH
`11 = 4 CQICH
`
`Type of contents on
`CQICHfor this SS
`000 = Fast D1,
`measurement/
`Default Feedback
`001 = Precoding
`Weight Matrix
`nformation
`010 = Channel
`Matrix H
`011 = Adaptive
`Rate Control
`nformation
`00 = Antenna
`Selection Index
`O1-111 = Reserved
`Period of the
`additional(CQICH_Num)
`CQI channels in frame
`
` ndex to uniquely
`
`identify the additional
`CQICH resources
`assigned to the SS
`
`variable The padding
`bits are used to
`ensure the IE size is integer
`number of bytes
`
`In Table 1, the initial 8 bits of an MAP information
`[0040]
`element for providing MIMO-based control
`information
`represent a type of a MAP information elementof 3 bits and
`a sub-type of 5 bits, and a length field of 4 bits represents
`length of the MIMO-based control information, which is
`located in the next field.
`
`[0041] The construction of the control information will be
`described. The field ‘MIMO type’ of 2 bits represents a
`MIMO mode. That is, when the field “MIMO type’ has a
`value of ‘00’, it indicates an open loop MIMO mode. When
`the field ‘MIMO type’ has a value of ‘01’, it indicates an
`antenna grouping MIMO mode. When the field ‘MIMO
`type’ has a value of ‘10’, it indicates an antenna selection
`
`MIMO mode. Whenthe field ‘MIMO type’ has a value of
`‘11’,
`it
`indicates a MIMO mode in which closed-loop
`precoding is performed.
`
`[0042] The field ‘Num-layer’ is a field for indicating the
`numberof layers, which is the number of signal branches
`input to the STC encoder.
`
`[0043] The field ‘Mt’is a field for indicating the number
`of streams output from the STC encoder. The transmitter
`determines the transmission matrices expressed by A, B and
`C in FIG.3 by using the valuesof the field ‘Num-layer’ and
`the field ‘Mt’. For example, when the field ‘Num-layer’ has
`a value of ‘10’ and the field ‘Mt’ has a value of ‘10’, the STC
`encoder performs STC encoding by using the horizontal
`encoding transmission matrix C.
`
`Thefield ‘Mode_Change’ is a field for indicating if
`[0044]
`the MIMO mode has changed. For example, when the
`“Mode_Change’ has a value of ‘1’,
`it means the use of a
`MIMO mode different from the previous MIMO mode.
`However, when the ‘Mode Change’ has a value of ‘0’, it
`means the current MIMO modeis identical to the previous
`MIMO mode. Inthis case, there is no changed information,
`it
`is not necessary to include the previous MIMO type
`information. Accordingly, it is possible to reduce the size of
`the Compact_DL-MAP message.
`
`[0045] Whenthe field ‘MIMOtype’ in Table 1 is desig-
`nated to ‘00’ or ‘11’, it indicates a matrix index used in an
`open loop or a preceding matrix index used in a closed-loop.
`
`[0046] Table 4 below or FIG.3 represents combinations
`available according to the number L of layers and the
`number Mt of streams. Further, when the ‘MIMOtype’ has
`a value of ‘11’, to which feedback precoding technologyis
`designated, from among the closed-loop MIMOtypes, it
`indicates
`a corresponding feedback precoding matrix
`through an index of 6 bits for feedback precoding while the
`STC encoderis used. Herein, the feedback preceding matrix
`may have a size of Mt (the number of streams)xNt (the
`numberof transmit antennas) and 64 different matrices at
`maximum, and the feedback precoding matrix may have a
`value depending on a generation algorithm, the number of
`layers, the number of streams, and the numberof transmit
`antennas.
`
`Matrix Indicator
`
`This field indicates
`MIMO matrix for the
`burst.
`
`TABLE 4
`
`if (Num_layer = 1){
`if (Mt = 1){
`SISO or AAS mode }
`elseif (Mt = 2){
`00 = A(TD);01 = C(VE);10 11 = Reserved}
`elseif (Mt = 3){
`00 = A(TD);01 = B(VE);10 = C(VE) 11 =
`Reserved}
`elseif (Mt = 4){
`00 = A(TD);01 = B(VE);10 = C(VE) 11 =
`Reserved}
`
`else if (Num_layer = 2){
`if (Mt = 2)f
`00 = C(HE);01 11 = Reserved}
`elseif (Mt = 3){
`00 = B(HE);01 11 = Reserved}
`elseif (Mt = 4){
`00 = B(HE);01 11 = Reserved}
`}
`
`
`
`US 2006/0098568 Al
`
`May 11, 2006
`
`TABLE 4-continued
`
`elseif (Num_layer = 3){
`if (Mt = 3)f
`00 = C(HE);01 11 = Reserved}
`
`elseif (Num_layer = 4){
`if (Mt = 4)f
`00 = C(HE);01 11 = Reserved}
`
`[0047] When the ‘MIMOtype’ in Table 1 has a value of
`‘01’ and antenna grouping technology is designated, it may
`indicate an antenna precoding matrix through an antenna
`grouping index of 4 bits in Table 2.
`
`[0048] Table 5 below represents matrix combinationsthat
`may be indicated by the antenna grouping index of4 bits in
`Table 2. Herein, the MIMO technologies in FIG.3 to be first
`applied are determined by the number of layers and the
`numberMtof streams in Table 1, and the MIMO technology
`to be finally applied is determined by the field ‘antenna
`grouping index of 4 bits’ as expressed by Table 5 below.
`
`[0049] As described above, STC encoding technology to
`be applied of the STC encoders 104 and 204 can be
`determined by the single field ‘antenna grouping index of 4
`bits’, and matrix values of the precoding blocks 105 and 205
`can be similarly understood. Accordingly, it is possible to
`efficiently reduce overhead of the control information mes-
`sage.
`
`TABLE5
`
`Antenna Grouping Index
`This field indicates antenna Grouping Index for the current burst.
`
`indicates a coding rate and a modulation scheme by a N,
`scheme in a Hybrid Automatic Request (H-ARQ) supple-
`mentary information retransmission (that
`is, Incremental
`Redundancy) mode. Further, when at
`least one layer
`includes an error in a mobile station, a non acknowledge-
`ment (NACK)is generated and combination data for coding
`gain increases for data of all layers are retransmitted. Fur-
`ther, when the Channel Quality Information Channel
`(CQICH)is assigned,thelast field indicates CQICH channel
`allocation information in order to load single CQI feedback
`information on each layer. Because each layer uses different
`encoding and modulation schemesas described above, each
`layer requires CQI feedback information.
`
`[0052] Table 3 illustrates the fields that a mobile station
`must refer to in order to feedback the CQI in a structure
`having multiple antennas or multiple layers. The field
`“CQICH-NUM’ representing the number of feedback chan-
`nels denotes the number of feedback channels to be simul-
`
`taneously transmitted by the mobile station. The field ‘CQI
`Feedback type’, which indicates the type of feedback infor-
`mation to be transmitted from each feedback channel,
`enables the mobile station to transmit different feedback
`
`information according to each allocated feedback channel.
`This enables the mobile station to transmit various feedback
`information required by a base station, thereby leading to
`more efficient operation of the MIMO technology.
`
`[0053] As described above, the transmitter, i.e., the base
`station, determines at least one matrix from among a plu-
`rality of transmission matrices by considering information
`fedback from the receiver, i.e., the mobile station, thereby
`performing STC encoding or precoding by means of the
`determined matrix and transmitting information for the
`determined matrix to the mobile station through a MIMO
`Compact DL-MAP message newly proposed by the present
`invention. Herein,
`the mobile station can understand the
`information for the matrix with reference to information for
`
`the layer values and the Mt values transmitted from the base
`station. Accordingly, the mobile station can perform decod-
`ing by using the transmission matrix corresponding to the
`information for the layer values and the Mt values while
`having already recognized the information as described in
`FIG.3.
`
`[0054] According to the present invention as described
`above, it is possible to efficiently notify a mobile station of
`various basic technologies for a MIMO and various MIMO
`precoding technologies using only a small quantity of data
`through downlink MAP message in a BWAsystem, thereby
`improving performance of the BWA system and increasing
`its cell capacity.
`
`[0055] While the present invention has been shown and
`described with reference to certain preferred embodiments
`thereof, it will be understood by those skilled in the art that
`various changes in form and details may be made therein
`without departing from the spirit and scope of the present
`invention as defined by the appended claims.
`
`Whatis claimedis:
`
`
`
`
`
`}e
`
`if (Num_layer = 1){
`if (Mt = 3)f
`0000 = A1;0001 = A2; 0010 = A3;
`w
`0011 =
`B1(VE); 0100 = B2(VE); 0101 = B3(VE);
`0110-1111
`= Reserved}
`elseif (Mt = 4){
`0000 = A1;0001 = A2; 0010 = A3;
`0011 = B1(VE); 0100 = B2(VE); 0101 = B3(VE); 0110 = B4(VE);
`0111 = BS(VE); 1000 = B6(VE);
`1001-1111
`= Reserved}
`
`lseif (Num_layer = 2){
`if (Mt = 3)
`Dx
`B1(HE); 0001 = B2(HE); 0010 = B3(HE);
`0000 =
`= Reserved}
`0011-1111
`elseif (Mt = 4){
`0000 = B1(HE); 0001 = B2(HE); 0010 = B3(HE); 0011 = B4(HE);
`0100 = BS(HE); 0101 = B6(HE);
`0110-1111
`= Reserved}
`
`[0050] When the ‘MIMOtype’ in Table 1 has a value of
`“10° and antennaselection technology is designated, it may
`indicate a precoding matrix throughthe field ‘antenna selec-
`tion index of 4 bits’ in Table 2. This indicates an antenna
`selected by performing an operation identical to that for the
`antenna grouping index.
`
`Thefield including the N.,, or the Downlink Inter-
`[0051]
`val Usage Code (DIUC)in table 2 indicates coding rates and
`modulation schemes for sets of encoders and modulators,
`which correspond to the numberof layers, through a value
`of 4 bits. That is, when a plurality of layers exists, the field
`
`1. A method for supporting various Multiple Input Mul-
`tiple Output
`(MIMO) and precoding technologies in a
`Broadband Wireless Access (BWA) system employing an
`antenna technique of a MIMO scheme, the method com-
`prising the steps of:
`
`
`
`US 2006/0098568 Al
`
`May 11, 2006
`
`configuring a downlink MAP message including infor-
`mation fields for indicating the MIMO technology and
`information fields for indicating various precoding
`technologies; and
`
`applying the MIMOtechnology to a mobile station by
`means of the downlink MAP message.
`2. The method as claimedin claim 1, wherein the down-
`link MAP message includes a field representing coding and
`modulation information according to layers and a field list
`information for Channel Quality Information (CQI) alloca-
`tion.
`3. The method as claimedin claim 2, wherein the down-
`link MAP message includesa field representing a numberof
`streams output from a Space Time Coding (STC) encoder,
`and indicates applicable MIMO technology in the field
`representing the coding and modulation information.
`4. The method as claimedin claim 3, wherein the down-
`link MAP message includes a field for indicating if a
`supportable mode has changed, and indicates a type of the
`STC encoder through a numberof layers included in the
`field representing the coding and modulation information,
`the numberof streams, and a value of the basic information
`field.
`
`5. The method as claimed in claim 1, wherein the step of
`applying the MIMOtechnology comprises the sub-steps of:
`
`determining MIMOtechnology to be applied based on a
`numberof layers and a numberof streams designated
`in the downlink MAP message, when the information
`field for indicating various precoding technologies,
`which is included in the downlink MAP message, is
`designated as antenna grouping precoding technology;
`
`determining MIMO technology to be applied by an
`antenna grouping index field designated in the down-
`link MAP message; and
`
`applying the determined MIMOtechnology.
`6. A method for supporting multiple antennas by a base
`station in a Broadband Wireless Access (BWA) communi-
`cation system using a Multiple Input Multiple Output
`(MIMO)scheme, the method comprising the steps of:
`
`receiving Channel Quality Information (CQI) from a
`mobile station;
`
`determining the MIMO schemeaccording to the CQI;
`
`encoding data according to the determined MIMO
`scheme; and
`
`configuring a downlink MAP message including the
`encoded data and information used for the encoding,
`and transmitting the downlink MAP message.
`7. The method as claimed in claim 6, wherein the MIMO
`scheme determines a transmission matrix according to a
`
`numberof layers corresponding to a number of modulators
`and a number of modulation streams output from an encoder
`in a transmitter of the base station.
`8. The method as claimed in claim 6, wherein the encod-
`ing includes one of a transmit diversity scheme, a vertical
`encoding scheme anda horizontal encoding scheme.
`9. The method as claimed in claim 6, wherein the infor-
`mation used for the encoding includes information defining
`a numberof layers corresponding to a number of modulators
`and a number of modulation streams output from an encoder
`in a transmitter of the base station, and transmits to the
`mobile station a downlink MAP message for indicating a
`transmission matrix determined by the numberoflayers and
`modulation streams.
`
`10. The method as claimed in claim 6, wherein the
`information used for the encoding includes information
`defining a number oflayers corresponding to a number of
`modulators and a numberof modulation streams output from
`an encoderin a transmitter of the base station, and transmits
`to the mobile station a downlink MAP message for indicat-
`ing antenna grouping/selection index information deter-
`mined by the numberof layers and modulation streams.
`11. An apparatus of a base station for application of a
`Multiple Input Multiple Output (MIMO) schemein a Broad-
`band Wireless Access (BWA) communication system using
`the MIMO scheme, the apparatus comprising:
`
`a first encoder for encoding data;
`
`a modulator for mapping on a complex plane the encoded
`data output from the first encoder;
`
`a second encoder for applying the MIMO schemeto the
`modulated data; and
`
`a precoding block for receiving a modulation stream from
`the second encoder and performing precoding for the
`received modulation stream.
`
`12. The apparatus as claimed in claim 11, wherein the
`second encoder includes a Space Time Coding (STC)
`encoder for performing space time coding.
`13. The apparatus as claimed in claim 11, wherein the
`precoding block operates when receiving Channel Quality
`Information (CQ]) fedback from a mobile station.
`14. The apparatus as claimed in claim 11, wherein the
`MIMOscheme determines a transmission matrix according
`to a numberoflayers corresponding to a number of modu-
`lators and a number of modulation streams output from the
`second encoder in a transmitter of the base station.
`
`15. The apparatus as claimed in claim 11, wherein the
`second encoder uses one of a transmit diversity scheme, a
`vertical encoding scheme and a horizontal encoding scheme.
`
`*
`
`*
`
`*
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`*
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`*
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