(12) INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT)
`
`(19) World Intellectual Property
`Organization
`International Bureau
`
` UMM UNAA
`
`(43) International Publication Date
`1 July 2004 (01.07.2004)
`
`PCT
`
`(10) International Publication Number
`WO 2004/056022 A2
`
`(51) International Patent Classification’:
`
`H04J
`
`(21) International Application Number:
`PCT/KR2003/00 1083
`
`(22) International Filing Date:
`
`2 June 2003 (02.06.2003)
`
`(25) Filing Language:
`
`(26) Publication Language:
`4
`(30) Priority Data:
`10-2002-0079598
`
`English
`.
`English
`
`ER
`13 December. 2007 13:12,2002)
`Co
`;
`(71) Applicant (for all designated States except US): ELEC-
`TRONICS AND TELECOMMUNICATIONS RE-
`
`SEARCH INSTITUTE [KR/KR]; 161, Gajeong-dong,
`Yuseong-gu, Daejon 305-350 (KR).
`
`(72) Inventors; and
`(75) Inventors/Applicants (for US only): LEE, Sok-kyu
`[KR/KR]; Jindalrae Apt.
`105-1506, Wolpyung 3-dong,
`Seo-gu, Daejeon-city 302-754 (KR). KIM, Kwang-Soon
`
`Sinseong-dong,
`109-1203,
`[KR/KR]; Hana Apt.
`(KR). CHANG,
`Yuseong-gu, Daejeon-city 305-721
`104-1409, Dun-
`Kyung-Hi
`[KR/KR]; Clover Apt.
`san-dong, Seo-gu, Daejeon-city 302-772 (KR).
`
`(74) Agent: YOU ME PATENT AND LAW FIRM; Teheran
`Bldg., 825-33, Yoksam-dong, Kangnam-ku, Seoul 135-080
`(KR).
`(81) Designated States (national): AE, AG, AL, AM, AT, AU,
`AZ, BA, BB, BG, BR, BY, BZ, CA, CH, CN, CO, CR, CU,
`C7, DE, DK, DM, DZ, EC, EE, ES, FI, GB, GD, GE, GH,
`GM,HR,HU,ID,IL, IN,IS, JP, KE, KG, KP, KZ, LC, LK,
`LR, LS, LT, LU, LV, MA, MD, MG, MK, MN, MW, MX,
`MZ, NI, NO, NZ, OM, PH,PL, PT, RO, RU, SC, SD,SE,
`SG, SK, SL, TJ, TM, TN, TR, TT, TZ, UA, UG, US, UZ,
`VC, VN, YU, ZA, ZM, ZW.
`
`(84) Designated States (regional): ARIPO patent (GH, GM,
`KE, LS, MW, MZ, SD, SL, SZ, TZ, UG, ZM, ZW),
`Eurasian patent (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM),
`European patent (AT, BE, BG, CH, CY, CZ, DE, DK, EE,
`ES, FI, FR, GB, GR, HU, IE, IT, LU, MC, NL, PT, RO,
`SE, SI, SK, TR), OAPI patent (BF, BJ, CF, CG, CI, CM,
`GA, GN, GQ, GW, ML, MR, NE, SN, TD, TG).
`
`[Continued on next page|
`
`(54) Titles APPARATUS AND METHODFOR SIGNAL CONSTITUTION FOR DOWNLINK OF OFDMA-BASED CELLULAR
`SYSTEM
`
`
`
`Traffic
`channe! data
`
`Transmission
`mode
`
`Perform coding,
`interleaving, and
`symbo!-mapping
`according to
`transmission mode
`
`Determine transmission mode
`and number of additional
`antennas
`
`Traffic requirement
`Moving speed
`
`Assign pilot symbols for
`additional! antenna
`
`§230
`
`Assign additional pilot
`symbols for basic/
`additional antennas
`
`Additional pilot symbol
`
`Traffic channel symbol
`
`OUT
`
`(57) Abstract: Disclosed are an adaptive pilot symbol assignment method that flexibly controls the number of transmit antennas
`according to each user’s moving speed, channel status, or user request, and assigns proper pilot symbols in the downlink of an
`OFDMA (Orthogonal Frequency Division Multiplexing Access) based cellular system; and a sub-carrier allocation method for high-
`speed mobile that allocates some sub-carriers to assign proper pilot symbols for ultrahigh-speed mobile users, and the rest of the
`sub-carriers to the other users to assign proper pilot symbols to the users, on the assumption that the ultrahigh-speed mobile users
`have a traffic volume almost insignificant to the whole traffic volume.
`
`Ford Motor Co.
`Exhibit 1013
`Page 001
`
`
`
`2004/056022A2IIMMINNNINIININIIIANTWIKITTANA
`
`Ford Motor Co.
`Exhibit 1013
`Page 001
`
`

`

`WO 2004/056022 A2
`
`[ITININUTNINITINE TICK TNUNTITTNTANIMt
`
`Published:
`— without international search report and to be republished
`uponreceipt of that report
`
`For two-letter codes and other abbreviations, refer to the “Guid-
`ance Notes on Codes and Abbreviations" appearing at the begin-
`ning of each regular issue of the PCT Gazette.
`
`Ford Motor Co.
`Exhibit 1013
`Page 002
`
`Ford Motor Co.
`Exhibit 1013
`Page 002
`
`

`

`WO 2004/056022
`
`PCT/KR2003/001083
`
`APPARATUS AND METHOD FORSIGNAL CONSTITUTION FOR
`DOWNLINK OF OFDMA-BASED CELLULAR SYSTEM
`
`1
`
`BACKGROUND OF THE INVENTION
`
`(a) Field of the Invention
`
`The present invention relates to an apparatus and methodfor signal
`
`constitution for a downlink of an OFDMA (Orthogonal Frequency Division
`
`Multiplexing Access) based cellular system. More specifically, the present
`
`invention relates to an apparatus and method for adaptive pilot symbol
`
`assignment and sub-carrier allocation that reduces transmission power
`
`consumption and overhead caused bypilot symbols and increases the total
`
`data rate on the downlink of an OFDMA-basedcellular system.
`
`(b) Description of the Related Art
`
`In the design of pilot assignment, it is necessary to use a sufficiently
`
`large numberof pilot symbols for the sake of preventing a deterioration of
`
`reception performance caused by a channel variation, and to prevent an
`
`excessive increase of a power loss or a bandwidth loss caused by pilot
`
`symbols above an expected value. The positioning (assignment) of pilot
`
`20
`
`symbols is of a great significance to the receiver of an OFDMA-based
`
`system, which estimates a transfer function value of channels in a two-
`
`dimensional (time, frequency) space. Hence, both the time domain and the
`
`frequency domain must be taken into consideration in pilot
`
`symbol
`
`assignmentso as to transmit the pilot symbols. In case of using a plurality of
`
`25
`
`antennas,
`
`the pilot symbols of the multiple antennas are assigned in
`
`Ford Motor Co.
`Exhibit 1013
`Page 003
`
`Ford Motor Co.
`Exhibit 1013
`Page 003
`
`

`

`WO 2004/056022
`
`PCT/KR2003/001083
`
`2
`consideration of both the time domain and the frequency domain.
`
`The distance between pilot symbols must be quite small in designing
`
`pilot symbols in the worst environment, or when using non-optimal channel
`estimation filters having a lower complexity.
`
`Let /,, be a sub-carrier bandwidth, then the maximum pilot distance
`
`N,,
`
`in the frequency domain based on the conventional sampling theory (F.
`
`Classen, M. Speth, and H. Meyr, “Channel estimation units for an OFDM
`
`system suitable for mobile communication”,
`
`in ITG Conference on Mobile
`
`Radio, Neu-Ulm, Germany, Sept. 1995)
`
`is determined by the following
`
`10
`
`formula:
`
`[Formula 1]
`
`N,<
`
`
`1
`
`Tmax Jos
`
`where f,,,,
`
`is the maximum exceedance delay time of a channel. The
`
`maximum pilot distance N,,
`
`in the frequency domain is determined by the
`
`following formula:
`
`[Formula 2]
`
`N;<
`
`
`1
`2f>T,
`
`where /, is the maximum Doppler frequency; and 7. is the symboltime.
`
`The symbol time 7,, during which the maximum pilot distance is
`
`20
`
`proportional to the coherent time, is normalized by the numberof symbols.
`
`So, the maximum pilot distance in the time domain is proportional to the
`
`coherent bandwidth and normalized by the sub-carrier bandwidth.
`
`Ford Motor Co.
`Exhibit 1013
`Page 004
`
`Ford Motor Co.
`Exhibit 1013
`Page 004
`
`

`

`WO 2004/056022
`
`PCT/KR2003/001083
`
`3
`The balanced design (P. Hoeheret al., “Pilot-symbol-aided channel
`
`estimation in time and frequency’, Multi-carrier Spread-Spectrum, accepted
`
`for publication in Kluwer Academic Publishers, 1997) defines that
`
`the
`
`estimation uncertainty in the time domain is equal to that in the frequency
`
`domain. Here, P. Hoeher et al. suggest a design guide having two-fold
`
`oversampling as defined by a heuristic formula as follows:
`
`[Formula 3]
`
`2fpT, Nz * Taahe “Ne 5
`where N,
`is
`the pilot distance in the frequency domain, The above-
`
`10
`
`mentioned pilot symbol assignmentis primarily a rectangularpilot symbol
`
`assignment, whichis illustrated in FIG. 1. FIGS. 2 and 3 show a straight pilot
`
`symbol assignment and a hexagonal pilot symbol assignment, respectively.
`
`Generally,
`
`the hexagonal pilot symbol assignment allows more efficient
`
`sampling, compared with two-dimensional signals, and exhibits excellent
`
`performance relative to other assignments. An example of the pilot symbol
`
`assignmentis disclosed in “Efficient pilot patterns for channel estimation in
`
`OFDM systems over HF channels” (M. J. Fernandez-Getino Garcia et al., in
`
`Proc IEEE VTC1999),
`
`As the pilot symbol assignment becomes denser,
`
`the channel
`
`20
`
`estimation performance becomes more excellent but
`
`the data rate is
`
`decreased. Hence,atrade-off lies between the data rate and the channel
`
`estimation performance(i.e., pilot symboldistance).
`
`There exits a pilot symbol distance that optimizes the trade-off
`
`Ford Motor Co.
`Exhibit 1013
`Page 005
`
`Ford Motor Co.
`Exhibit 1013
`Page 005
`
`

`

`WO 2004/056022
`
`PCT/KR2003/001083
`
`4
`betweenthe improved channel estimation and the signal-to-noise ratio (SNR)
`
`reduced by data symbols. By varying the pilot symbol distances N,, and N,.,
`
`the values approximate to the optimum with reference to the performance of
`
`bit error rate (BER) can be determined. In FIG. 1, for example, NV, =4 and
`
`N, =3 in optimum means that one twelfth (about 8%) of the consumed
`
`transmission power and bandwidth are usedforpilot symbols.
`
`In this optimal assignmentof pilot symbols, the channel environment
`
`and the moving speed of the mobile users are of a great importance as
`
`parameters to be considered.
`
`M
`
`TION
`
`It is an advantage of the present invention to provide an apparatus
`
`and method for adaptive pilot symbol assignment and sub-carrier allocation
`
`that reduces transmission power and overhead causedbypilot symbols and
`increases the total data rate on a downlink in an OFDMA-based cellular
`system.
`|
`
`In one aspect of the present invention, there is provided a downlink
`
`signal constitution method, which is for a downlink of a cellular system using
`
`an orthogonal frequency division multiplexing access method, the downlink
`
`signal constitution method including: (a) coding,
`
`interleaving, and symbol-
`
`20
`
`mapping data of a common channel and a control channel, and assigning
`
`fundamental pilot symbols, necessary for a demodulation of the common
`
`channel and the control channel,
`
`to time, frequency, and antenna;
`
`(b)
`
`receiving data to be transmitted through a traffic channel of each user, and
`
`Ford Motor Co.
`Exhibit 1013
`Page 006
`
`Ford Motor Co.
`Exhibit 1013
`Page 006
`
`

`

`WO 2004/056022
`
`PCT/KR2003/001083
`
`5
`
`determining a transmission mode of each user according to the user’s
`
`moving speed, channel information, and traffic requirement; (c) determining
`
`additional pilot symbols, additionally necessary for a demodulation of the
`
`traffic channel, according to the transmission mode and moving speed by
`
`users; and (d) coding, interleaving and symbol-mapping the data ofthe traffic
`
`channel according to the transmission mode by users, and assigning the
`
`mapped symbols and the additional pilot symbols according to time,
`
`frequency and antenna.
`
`In another aspect of the present
`
`invention,
`
`there is provided a
`
`downlink signal constitution method, which is for a cellular system using an
`
`orthogonal frequency division multiplexing access method,
`
`the downlink
`
`signal constitution method including: (a) dividing users into a first user group
`
`including high-speed mobile users and a second user group including the
`
`rest of the users,
`
`in consideration of each user’s moving speed and traffic
`
`15
`
`volume; (b) allocating a first sub-carrier band for the first user group, and a
`
`second sub-carrier band for the second user group; and (c) assigning pilot
`
`symbolsto the first and second sub-carrier bands, the pilot symbols assigned
`
`to the first sub-carrier band being different in assignment density from the
`
`pilot symbols assigned to the second sub-carrier.
`
`20
`
`In a further aspect of the present invention,
`
`there is provided a
`
`downlink signal constitution apparatus, which is for a cellular system using
`
`an orthogonal frequency division multiplexing access method, the downlink
`
`signal constitution apparatus including: a first memory for storing traffic
`
`channel
`
`information of each user; a second memory for storing channel
`
`Ford Motor Co.
`Exhibit 1013
`Page 007
`
`Ford Motor Co.
`Exhibit 1013
`Page 007
`
`

`

`WO 2004/056022
`
`PCT/KR2003/001083
`
`6
`information, traffic requirement, and moving speed information of each user;
`
`a transmission user and transmission mode determiner for determining a
`
`transmission user and a transmission mode according to a defined method
`
`using the information stored in the second memory; a traffic channel*
`
`processor for reading the traffic channel
`
`information stored in the first
`
`memory according to the transmission mode determined by the transmission
`
`user and transmission mode determiner, and performing coding, interleaving,
`
`and symbol-mapping of the traffic channel; an additional pilot symbol
`
`generator
`
`for generating additional
`
`pilot
`
`symbols necessary for
`
`a
`
`10
`
`demodulation of the traffic channel, using the transmission mode determined
`
`by the transmission user and transmission mode determiner and the moving
`
`
`
`speed information stored in and a_time/sub-the second memory;
`
`
`
`carrier/antenna mapper for multiplying the traffic channel symbols output
`
`from the traffic channel processor and the additional pilot symbols output
`
`15
`
`from the additional
`
`pilot
`
`symbol generator by a channel gain
`
`by
`
`. channels/users, and mapping the resulting symbols to time, sub-carrier, and
`
`antenna by a defined method.
`
`In a still further aspect of the present invention, there is provided a
`
`recording medium with a built-in program, which implements a downlink
`
`20
`
`signal constitution method for a cellular system using an orthogonal
`
`frequency division multiplexing access method,
`
`the program including: a
`
`function of coding,
`
`interleaving, and symbol-mapping data of a common
`
`channel and a control channel, and assigning fundamental pilot symbols,
`
`necessary for a demodulation of the common channel and the control
`
`Ford Motor Co.
`Exhibit 1013
`Page 008
`
`Ford Motor Co.
`Exhibit 1013
`Page 008
`
`

`

`WO 2004/056022
`
`PCT/KR2003/001083
`
`7
`channel, to time, frequency, and antenna; a function of receiving data to be
`
`transmitted through a traffic channel of each user, and determining a
`
`transmission mode of each user according to the user’s moving speed,
`
`channel
`
`information, and traffic requirement; a function of determining
`
`additional pilot symbols, additionally necessary for a demodulation of the
`
`traffic channel, according to the transmission mode and moving speed by
`
`users; and a function of coding, interleaving and symbol-mapping the data of
`
`the traffic channel according to the transmission mode by users, and
`
`assigning the mapped symbols and the additional pilot symbols according to
`
`time, frequency, and antenna.
`
`In a still further aspect of the present invention, there is provided a
`
`recording medium with a built-in program, which implements a downlink
`
`signal constitution method for a cellular system using an orthogonal
`
`frequency division multiplexing access method,
`
`the program including: a
`
`function of dividing users into a first user group including high-speed mobile
`
`users and a second user group including the rest of
`
`the users,
`
`in
`
`consideration of each user’s moving speed andtraffic volume; a function of
`
`allocating a first sub-carrier band for the first user group, and a second sub-
`
`carrier band for the second user group; and a function of assigning pilot
`
`20
`
`symbols to thefirst and second sub-carrier bands, the pilot symbols assigned
`
`to the first sub-carrier band being different in assignment density from the
`
`pilot symbols assigned to the second sub-carrier.
`
`Ford Motor Co.
`Exhibit 1013
`Page 009
`
`Ford Motor Co.
`Exhibit 1013
`Page 009
`
`

`

`WO 2004/056022
`
`PCT/KR2003/001083
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`8
`
`The accompanying drawings, which are incorporated in and
`
`constitute a part of the specification,
`
`illustrate an embodiment of the
`
`invention, and, togetherwith the description, serve to explain the principles of
`
`the invention:
`
`FIG.
`
`1
`
`is an exemplary diagram of a rectangular pilot symbol
`
`assignment;
`
`FIG. 2 is an exemplary diagram of a straight pilot
`
`symbol
`
`assignment;
`
`FIG. 3 is an exemplary diagram of a hexagonal pilot symbol
`
`assignment;
`
`FIG. 4 is a flow chart showing a symbol assignment method for a
`
`downlink of an OFDMA-based cellular system according to an embodiment
`
`of the presentinvention;
`
`FIG. 5 is a detailed diagram showing a symbol assignment method
`
`for the traffic channelof FIG. 4;
`
`FIG. 6 is a diagram showing a downlink signal constitution method
`
`according to the embodimentof the present invention;
`
`FIG. 7 is an exemplary diagram ofa pilot symbol assignmentfor low-
`
`20
`
`speed mobile users using four antennas;
`
`FIG. 8 is an exemplary diagram of a pilot symbol assignment for
`
`high-speed mobile users using two antennas;
`
`FIG. 9 is an exemplary diagram showing a downlink signal
`
`constitution method when using additional antennas only in a part of the
`
`Ford Motor Co.
`Exhibit 1013
`Page 010
`
`Ford Motor Co.
`Exhibit 1013
`Page 010
`
`

`

`WO 2004/056022
`
`PCT/KR2003/001083
`
`whole band in an FDD system;
`
`FIG. 10 is a diagram of a downlink signal constitution apparatus for
`an OFDMA-based cellular system) according to the embodiment of the
`
`present invention;
`
`FIG. 11 is a detailed flow chart showing a pilot symbol assignment
`
`according to sub-carrier allocation; and
`
`FIG. 12 is an exemplary diagram showing a pilot symbol assignment
`
`according to a sub-carrier allocation for high-speed mobile users and a
`
`moving speed.
`
`ETAILED DESCRIPTI
`
`E PREFERRE
`
`ODIMENTS
`
`In the following detailed description, only the preferred embodiment
`
`of the invention has been shown and described, simply by wayofillustration
`
`of the best mode contemplated by the inventor(s) of carrying out the
`
`invention. As will be realized, the invention is capable of modification in
`
`various obvious
`
`respects,
`
`all without departing from the
`
`invention.
`
`Accordingly, the drawings and description are to be regardedasillustrative in
`
`nature, and notrestrictive.
`
`FIG. 4 is a diagram showing a downlink symbol assignment method
`
`for an OFDMA-basedcellular system according to an embodiment of the
`
`presentinvention.
`
`The symbol assignment method according to the embodimentof the
`
`present invention comprises, as shown in FIG. 4, a symbol assignment step
`
`S100 for common/control channels, a symbol assignment step S200 for
`
`Ford Motor Co.
`Exhibit 1013
`Page 011
`
`Ford Motor Co.
`Exhibit 1013
`Page 011
`
`

`

`WO 2004/056022
`
`PCT/KR2003/001083
`
`10
`traffic channels, and a traffic channel signal constitution step S300.
`
`More
`
`specifically,
`
`the
`
`symbol
`
`assignment
`
`step
`
`$100
`
`for
`
`common/control
`
`channels performs
`
`coding,
`
`interleaving,
`
`and symbol
`
`mapping on data of common andcontrol channels, and assigns the mapped
`
`symbols to time, frequency, and antennas. Also, fundamental pilot symbols
`
`necessary for demodulation of the common and control channels are
`
`assignedto time, frequency, and antennas.
`
`The symbol assignment step S200fortraffic channels receives data
`
`to be transferred through the traffic channel of each user; determines each
`
`10
`
`user’s transmission mode according to the user’s moving speed, channel
`
`information, and traffic requirement; performs coding,
`
`interleaving, and
`
`symbol-mapping according to the transmission mode of the user; and
`
`assigns the traffic channel symbols of each user to time, frequency, and
`
`antennas. Also, pilot symbols additionally necessary for a demodulation of
`
`15
`
`the traffic channel are generated according to the transmission mode by
`
`users, and assigned to time, frequency, and antennas.
`
`The traffic channel signal constitution step S300 constitutes the
`
`signal of the traffic channel using the traffic channel symbols of each user
`
`and the additional pilot symbols output from the step S200.
`
`FIG. 5 is a detailed diagram of the symbol assignment S200 for
`
`traffic channels shownin FIG. 4.
`
`Whenthe basestation has information about the moving speed and
`
`channelstatus of each user, a required numberof pilot symbols are inserted,
`
`reducing transmission power and overhead causedbypilot symbols.
`
`Ford Motor Co.
`Exhibit 1013
`Page 012
`
`Ford Motor Co.
`Exhibit 1013
`Page 012
`
`

`

`WO 2004/056022
`
`PCT/KR2003/001083
`
`11
`According to the embodiment of
`
`the present
`
`invention,
`
`the
`
`transmitter antennas are divided into basic antennas and additional antennas.
`
`The basic antenna refers to an antenna used for transmitting common and
`
`control channels, while the additional antenna refers to an antenna
`
`additionally used to enhance the transmission rate or performance of the
`
`traffic channel of the user.
`
`In the OFDMA system, one frequency bandis dividedinto a plurality
`
`of sub-carrier bands to transmit the traffic channel of each user through the
`
`allocated sub-carriers. Namely, the OFDMA system properly allocates a sub-
`
`carrier band according to the user’s moving speed, channel environment,
`
`and traffic requirement, or selects a defined sub-carrier band, determines the
`
`number of transmitter antennas according to the user’s moving speed,
`
`channel environment, and traffic requirement, and then assigns additionally
`
`necessary pilot symbols to the allocated sub-carrier band.
`
`Morespecifically, as illustrated in FIG. 5, the OFDMA system stores
`
`data to be transmitted througha traffic channel, in step S210.
`
`The transmission mode and the numberof additional antennas are
`
`determined in consideration of the user’s channel information (i.e., channel
`
`status), traffic requirement, and moving speed, in step S220.
`
`20
`
`In step S230,
`
`the system assigns pilot symbols for additional
`
`antennas, when the additional antennas are needed according to the
`
`transmission mode determinedin the step S220.
`
`The additional pilot symbols according to the moving speed of the
`
`basic antennas
`
`and the additional antennas are then assigned in
`
`Ford Motor Co.
`Exhibit 1013
`Page 013
`
`Ford Motor Co.
`Exhibit 1013
`Page 013
`
`

`

`WO 2004/056022
`
`PCT/KR2003/001083
`
`12
`consideration of the user’s moving speed, in step S240.
`
`The system performs coding,
`
`interleaving, and symbol mapping
`
`using the transmission mode determined in the step S220 and thetraffic
`
`channel data stored in the step S210 to generate coded, interleaved, and
`
`symbol-mappedtraffic channel symbols, in step $250.
`
`In the step S220, the transmission mode for each useris determined
`
`independently, or the transmission modefor multiple users is determined by
`
`optimization in consideration of the total transmission rate, the quality of
`
`service, or the total transmission power.
`
`FIG. 6 is an exemplary diagram showing a downlink signal
`
`constitution method according to the embodimentof the presentinvention.
`
`In FIG. 6, when using one basic antenna and at most
`
`three
`
`additional antennas, the pilot symbols are assigned to the sub-carrier band,
`
`whichis allocated to a user 1 moving at high speed with one basic antenna,
`
`15
`
`a user 2 moving at low speed with one additional antenna, a user 3 moving
`
`at low speed with three additional antennas, and a user 4 moving at high
`
`speed with one additional antenna.
`
`In FIG. 6, seventeen OFDM symbols constitute one slot. FIG. 6
`
`showsthe case where a demodulation can be enabled with one pilot symbol
`
`20
`
`in one slot in the time domain because the moving speedis low.
`
`Referring to FIG. 6, the common and contro! channels are used to
`
`transmit OFDM symbols such aspilot symbols of the basic antenna, and
`
`demodulate them irrespective of the moving speed of the users. Thetraffic
`
`channelis usedto transmit the additional pilot symbols necessary according
`
`Ford Motor Co.
`Exhibit 1013
`Page 014
`
`Ford Motor Co.
`Exhibit 1013
`Page 014
`
`

`

`WO 2004/056022
`
`PCT/KR2003/001083
`
`13
`to the moving speed of the users and the number of antennas in the
`
`allocated sub-carrier band by users.
`
`FIG. 7 is an exemplary diagram showing a pilot symbol assignment
`
`in the sub-carrier band allocated to a low-speed mobile user using one basic
`
`antenna and three additional antennas according to the embodiment of the
`
`presentinvention.
`
`The pilot symbols (NV, =5) of the basic antenna (antenna 0) and the
`
`common and control channels are transmitted for the first OFDMA symbol,
`
`and the traffic channel is transmitted for the other OFDMA symbols.Thepilot
`
`symbols of the additional antennas (antenna 1, antenna 2, antenna 3) are
`
`additionally transmitted. In the meantime, the symbols of the traffic channel
`
`can be generated by any oneofthe following methods:(1) a first method of
`
`generating traffic channel symbols previously in consideration of the number
`
`of additional pilots; (2) a second method of generating the maximum number
`
`15
`
`of traffic channel symbols and then puncturing at positions to transmit
`
`additional pilot symbols; and (3) a third method of generating traffic channel
`
`symbols previously in consideration of the numberof a part of additionalpilot
`
`symbols, and then puncturing at positions to transmit
`
`the rest of the
`
`additional pilot symbols.
`FIG. 8 is an exemplary diagram showinga pilot synibil assignment
`
`in the sub-carrier band allocated to a high-speed mobile user using one
`
`basic antenna and one additional antenna according to the embodimentof
`
`the presentinvention.
`
`Thepilot symbols (NV, = 5) of the basic antenna (antenna 0) and the
`
`Ford Motor Co.
`Exhibit 1013
`Page 015
`
`Ford Motor Co.
`Exhibit 1013
`Page 015
`
`

`

`WO 2004/056022
`
`PCT/KR2003/001083
`
`14
`common and control channels are transmitted for the first OFDMA symbol,
`
`and the traffic channel is transmitted for the other OFDMA symbols. Thepilot
`
`symbols of the additional antenna (antenna 1) are additionally transmitted.
`
`In the meantime, the symbols ofthe traffic channel can be generated
`
`by one of the following methods:
`
`(1) a first method of generating traffic
`
`channel symbols previously in consideration of the number of additional
`
`pilots; (2) a second method of generating the maximum numberoftraffic
`
`channel symbols and then puncturing at positions to transmit additional pilot
`
`symbols; and (3) a third method of generating traffic channel symbols
`
`previously in consideration of the numberof a part of additional pilot symbols,
`
`and then puncturing at positions to transmit the rest of the additional pilot
`
`symbols.
`
`In summary, there are four canes of pilot symbol assignment in
`
`relation to the numberof antennasofthe traffic channel:
`
`15
`
`(1) moving at a low speed with one basic antenna — using no
`
`additional pilot symbol;
`
`(2) moving at low speed with additional antennas — assigning pilot
`
`symbols for additional antennas;
`
`(3) moving at high speed with one basic antenna — additionally
`
`20
`
`inserting pilot symbols for basic antenna in conformity to the high-speed
`
`environment; and
`
`(4) moving at high speed with additional antennas — additionally
`
`inserting pilot symbols for basic and additional antennas in consideration of
`
`the moving speed.
`
`Ford Motor Co.
`Exhibit 1013
`Page 016
`
`Ford Motor Co.
`Exhibit 1013
`Page 016
`
`

`

`WO 2004/056022
`
`PCT/KR2003/001083
`
`15
`To use the methodsillustrated in FIGS. 4 to 8, the base station must
`
`have information about the channel information, moving speed, andtraffic
`
`requirement of each user. The moving speed is measured at the basestation,
`
`or is measured at the mobile station and then reported to the basestation.
`
`5
`
`Thetraffic requirement is reported to the base station by the mobile station,
`
`or is detected by the base station from the amount or characteristic of data to
`
`be transmitted. The channel information is measured at the base station, or
`
`is measured at the mobile station and then reported to the base station. The
`
`former case is primarily for the TDD (Time Division Duplex) based system,
`
`10
`
`and thelatter one is for the FDD (Frequency Division Duplex) based system.
`
`In the former case, the mobile station sends a signal (e.g., preamble,
`
`pilot, etc.) for channel measurement, and then the base station measures
`
`the channel information of the uplink by the respective antennas based on
`
`the received signal. The base station acquires channel information of the
`
`downlink using the reciprocity of channels because the uplink and the
`
`downlink have the same channel information because they use the same
`
`frequency band.
`
`Contrarily,
`
`in the FDD system, the mobile station previously sends
`
`pilots of additional antennas so as to perform a channel estimation of the
`
`additional antennas.
`
`FIG. 9 is an exemplary diagram showing a downlink signal
`
`constitution method when using additional antennasonly in a defined band in
`
`the FDD system.
`
`Namely, FIG. 9 shows the addition of an appropriate quantity of pilot
`
`Ford Motor Co.
`Exhibit 1013
`Page 017
`
`Ford Motor Co.
`Exhibit 1013
`Page 017
`
`

`

`WO 2004/056022
`
`PCT/KR2003/001083
`
`16
`symbols for additional antennasto the first symbol only in a defined band so
`
`as to reduce overhead causedby transmitting pilots of additional antennas.
`
`In FIG. 9, one basic antenna (antenna 1) is used, and the third band
`
`is a band available for using at most three additional antennas, the fourth
`
`band being a band available for using at most one additional antenna, the
`
`_ other bands not being available for using additional antennas.
`
`FIG. 10 is a diagram of a downlink signal constitution apparatus 100
`
`for an OFDMA-basedcellular system according to the embodiment of the
`
`presentinvention.
`
`10
`
`The downlink signal
`
`constitution apparatus 100 comprises a
`
`common/control channel processor 110,
`
`a fundamental pilot
`
`symbol
`
`generator 120, a traffic channel information memory 130, a traffic channel
`
`processor 140, a channel
`
`information/traffic requirement/moving speed
`
`memory 150, a transmission user and transmission mode determiner 160, an
`
`additional pilot
`
`symbol generator 170, and a_time/sub-carrier/antenna
`
`mapper 180.
`
`The
`
`common/control
`
`channel
`
`processor
`
`110
`
`encodes
`
`and
`
`interleaves the common/contro! channel information, and maps the coded
`
`and interleaved common/control channel information to symbols to generate
`
`a coded/interleaved/symbol-mapped common/control channel symbol. The
`
`fundamental pilot symbol generator 120 generates a fundamentalpilot
`
`symbol. The fundamental pilot
`
`symbol
`
`is a pilot
`
`symbol
`
`transmitted
`
`irrespective of the transmission modeofthe traffic channel of the user, and
`
`in FIGS. 6 and 9, refers to a pilot symbol transmitted for the first OFDM
`
`Ford Motor Co.
`Exhibit 1013
`Page 018
`
`Ford Motor Co.
`Exhibit 1013
`Page 018
`
`

`

`WO 2004/056022
`
`PCT/KR2003/001083
`
`symbolof theslot.
`
`The traffic channel information memory 130 stores the user’s traffic
`
`channel information, and the channel information/traffic requirement/moving
`
`speed memory 150 stores the user’s channelinformation, traffic requirement,
`
`and moving speed information.
`
`The transmission user and transmission mode determiner 160
`determines the transmission user and each transmission mode according to
`
`a
`
`defined method
`
`using
`
`the
`
`information
`
`stored
`
`in
`
`the
`
`channel
`
`information/traffic
`
`requirement/moving speed memory 150. The traffic
`
`channel processor 140 reads the traffic channel information stored in the
`
`traffic channel information memory 130 according to the transmission mode
`
`determined by the transmission user and transmission mode determiner 160,
`
`encodesandinterleaves the traffic channel information, and maps the coded
`
`and
`
`interleaved
`
`traffic
`
`channel
`
`information
`
`to
`
`generate
`
`a
`
`15
`
`coded/interleaved/symbol-mappedtraffic channel symbol.
`
`The additional pilot symbol generator 170 generates an additional
`
`pilot symbol according to the number of antennas and the moving speed
`
`determined by each user’s transmission mode. The additionalpilot symbolis
`
`a pilot symbol additionally transmitted other than the fundamental pilot
`
`20
`
`symbol for the respective users, and in FIGS. 6 and 9, refers to the pilot
`
`symbols other than the pilot symbol transmitted for the first OFDM symbolof
`
`the slot.
`
`The
`
`time/sub-carrier/antenna| mapper
`
`180 multiplies
`
`the
`
`coded/interleaved/symbol-mapped
`
`common/control
`
`channel
`
`symbol
`
`Ford Motor Co.
`Exhibit 1013
`Page 019
`
`Ford Motor Co.
`Exhibit 1013
`Page 019
`
`

`

`WO 2004/056022
`
`PCT/KR2003/001083
`
`generated
`
`from the
`
`18
`common/control
`
`channel
`
`processor
`
`110,
`
`the
`
`coded/interleaved/symbol-mappedtraffic channel symbol generated from the
`
`traffic channel processor 130, the fundamental pilot symbol generated from
`
`the fundamental pilot symbol generator 120, and the additional pilot symbol
`
`generated from the additional pilot symbol generator 170 by channel gain
`
`information by channels or users, and maps the channel symbols to time,
`
`sub-carrier, and antenna by a defined method.
`
`The time/sub-carrier/antenna mapper 180 can use any one of the
`
`following methods: (1) a first method of generating traffic channel symbols
`
`previously in consideration of the numberof additional pilots; (2) a second
`
`method of generating the maximum numberoftraffic channel symbols and
`
`then puncturing at positions to transmit additional pilot symbols; and (3) a
`
`third method
`
`of generating traffic
`
`channel
`
`symbols
`
`previously
`
`in
`
`consideration of the numberof a part of additional