`Patent Cooperation Treaty (PCT)
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`the
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`International application number: PCT/CA0S/000958
`
`International filing date:
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`22 June 2005 (22.06.2005)
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`Document type:
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`Certified copy of priority document
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`Country/Office: US
`Number:
`60/619,461
`15 October 2004 (15.10.2004)
`Filing date:
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`Date of receipt at the International Bureau:
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`09 September 2005 (09.09.2005)
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`Remark:
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`compliance with Rule 17 .1 ( a) or (b)
`
`World Intellectual Property Organization (WIPO) - Geneva, Switzerland
`Organisation Mondiale de la Propriete Intellectuelle (OMPI) - Geneve, Suisse
`
`
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`PCT/CA
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`2 0 0 5 0 0 0 0 9 5 8
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`UNITED STATES DEPARTMENT OF COMMERCE
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`APPLICATION NUMBER: 60/619,461
`F ILING DATE: October 15, 2004
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`HANG
`NEPEAN, ONTARIO, CANADA
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`MAC LAYER AND PHYSICAL LAYER SYSTEMS AND METHODS
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`ZHANG
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`REGISTRATION NO. --'3°"1"",6""'1"'"8 _ ____ _
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`Copy provided by USPTO from the IFW lmaqe Database on 05/12/200S
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`(cid:173)
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`I Docket Number 17399ROUS01P
`
`j First Named Inventor
`
`!HANG ZHANG
`
`Given Name (first and middle 1lf anvil
`
`Famllv or Surname
`
`Residence
`ICitv and either Slate or Forelon Counl!vl
`
`INVENTOR(S)fAPPLICANT(S)
`
`MO-HAN
`
`PEIYING
`
`WEN
`
`JIANGLEI
`
`FONG
`
`ZHU
`
`TONG
`
`MA
`
`L'ORIGINAL, ONTARIO, CANADA
`
`KANATA, ONTARIO, CANADA
`
`OTTAWA, ONTARIO, CANADA
`
`OTTAWA, ONTARIO, CANADA
`
`}\
`
`Number __ oo_i; __ of ONE
`
`WARNING: Information on this fonn may become public. Credit card information should not be
`Jncluded on this form. Provide credit card Information and autherizallon on PT0-2038.
`
`Copy provided by USPTO from the IFW
`Image Database on 05/12/2005
`
`
`
`Attorney Docket No. 17399ROUS01P
`
`PROVISIONAL PATENT APPLICATION
`
`SUBMITTED ON OCTOBER 15, 2004
`
`MAC LAYER AND PHYSICAL LAYER SYSTEMS AND METHODS
`
`TITLE:
`
`INVENTOR:
`
`HANG ZHANG
`24 Gardengate Way
`Nepean, Ontario
`Canada
`K2GSZ1
`
`MO-HAN FONG
`1578 Bay Road
`L'Original, Ontario
`Canada
`K0BlKO
`
`PEIYINGZHU
`16 Pebble Creek Crescent
`Kanata, Ontario
`K2M2L4
`
`WENTONG
`12 Whitestone Drive
`Ottawa, Ontario
`Canada
`K2C4A7
`
`JIANGLEIMA
`3 Bon Echo Crescent
`Ottawa, Ontario
`K2M2W5
`
`0
`
`Copy provided by USPTO from the IFW Image Database on 05/12/2005
`
`
`
`Attorney Docket No. 17399ROUS0IP
`
`TABLE OF CONTENTS
`
`Section 1
`
`RESOURCE ALLOCATION SYSTEM AND METHOD FOR DE~RMINISTIC
`TRAFFIC
`
`0
`
`Section 2
`
`FEEDBACK HEADER SYSTEMS AND METHODS
`
`..
`Section 3
`
`Section 4
`
`~
`
`HIERARCHICAL MAP STRUCTURE SYSTEMS AND METHODS
`
`PILOT PATTERN SYSTEM AND METHOD
`
`Section 5
`
`SHORT DATA BURST SYSTEMS AND METHODS
`
`Section 6
`
`UPLINK CHANNEL SYSTEMS AND METHODS
`
`Section 7
`
`DOWNLINK RESOURCE ALLOCATION SYSTEM AND METHOD
`
`1
`
`Coov orovided bv USPTO from the lFW lmaQe Database on 05/12/2005
`
`
`
`Attorney Docket No. 17399ROUS0IP
`
`RESOURCE ALLOCATION SYSTEM AND METHOD FOR DETERMINISTIC TRAFFIC
`
`Field of the Invention
`
`This invention generally relates to the field of wireless communications. More specificaUy to resource
`allocation systems and methods for broadband mobile wireless metropolitan area networks including networks
`operating according to the IEEE 802.16(e) standard.
`
`Background of the Invention
`
`In the current 802. I 6e standard draft (p802. I 6e/D5), the downlink / uplink (DI/UL) resource assignments are
`i'fldicated by DI./UL map information elements (IEs) in the DUUL-MAP message. The current resource
`assignment is performed on the frame-by-frame basis.
`
`For services, like unsolicited grant service (UGS) and real-time polling service (rtPS), the data arriving arriving
`at the transmitter (i.e. BS for DL and MSS for UL) has certain deterministic patterns and in certain cases may
`also be stream-like. For these types of traffic, if resource assignment has to be performed on a frame-by-frame
`basis, large amounts of MAC overhead will be incurred.
`
`A need exists therefore for improved systems and methods for resource aUocation for handling deterministic
`traffic.
`
`2
`
`Copy provided by USPTO from the IFW Image Database on 05/12/2005
`
`
`
`Summary of the Invention
`
`Attorney Docket No. 17399ROUS01P
`
`It is an object of the invention to simplify the resource assignment for UGS and rtPS, to reduce unnecessary
`MAC overhead.
`
`It is an object of the invention to provide a resource allocation system and method for use in networks operating
`in accordance with the IEEE 802.16 standard.
`
`Further objects of the invention include provide the following:
`' • A DL MAP IE - According to this aspect of the invention the dedicated resource allocation IE may
`allocate dedicated DL resource for a certain period of time. Such an allocation may be de-allocated or
`modified at any time
`• A UL MAP IE - According to this aspect of the invention the Dedicated resource allocation IE may
`allocate dedicated UL resource for a certain period of time. Such an allocation may be de-allocated and
`modified at any time
`
`It is a further object of the invention to provide a resource allocation system and method wherein if a dedicated
`DL resource is defined as a DL region in every Nth frame and assigned to a MSS, the MSS may decode this
`dedicated channel until the end of the assignment period or until receiving a Dedicated resource IE for the de(cid:173)
`allocation. In addition to the dedicated resource, additional DL resource may also be allocated by using normal
`DL MAP IE if the dedicated resource is not enough to send the buffered data.
`
`It is a further object of the invention to provide a resource allocation system and method wherein if a dedicated
`UL resource is defined as a UL region in every Nth frame and assigned to a MSS, the MSS may transmit UL
`data on this dedicated channel until the end of the assignment period or until receiving Dedicated resource IE
`for the de-allocation. In addition to the dedicated resource, some extra UL resource may also be allocated by
`using normal DL MAP IE if the MSS requires some extra UL resource.
`
`It is another object of the invention to provide for the power efficient operation of MSSs, wherein the MSS
`monitors the DUUL-MAP messages in the frame where the MSS needs to decode data on the DL dedicated
`resource or needs to send data using the UL dedicated resource. In this case, the extra resource allocation
`In accordance with an embodiment of the invention the MSS monitors only the
`happens in such a frame.
`DUUL-MAP messages in the frame where the MSS needs to decode data on the DL dedicated resource or
`needs to send data using the UL dedicated resource.
`
`It is another object of the invention that DUUL modulation and coding schemes (called DIUC and UIUC
`rhpectively) may be changed in a slow fashion. The modification may be based on long term C/I statistics.
`
`3
`
`Copy provided by USPTO from the IFW Image Database on 05/12/2005
`
`
`
`Brief Description of the Figures
`
`Attorney Docket No. l 7399ROUS01 P
`
`Figure 1 is a block representation of a cellular communication system.
`Figure 2 is a block representation of a base station according to one embodiment of the present invention.
`Figure 3 is a block representation of a mobile terminal according to one embodiment of the present invention.
`Figure 4 is a logical breakdown of an OFDM transmitter architecture according to one embodiment of the
`.
`present invention .
`Figure 5 is a logical breakdown of an OFDM receiver architecture according to one embodiment of the present
`
`~nvention.
`Figure 6 illustrates a pattern of sub-carriers for carrying pilot symbols in an OFDM environment.
`
`Detailed Description of Embodiments of the Invention
`
`The following modification is based on IEEE standard p802.16e/D5 which is hereby incorporated by reference.
`
`In accordance with embodiments of the invention dedicated resource allocation information elements (IEs) are
`described.
`
`In accordance with an embodiment of the invention Table 1 provides a DL MAP IE format that may be used by
`a Basestation (BS) to allocate dedicate DL resource allocation to one or more MSSes and to de(cid:173)
`allocation/modify an existing allocation
`
`4
`
`Copy provided by USPTO from the IFW Image Database on 05/1212005
`
`
`
`Attorney Docket No. 17399ROUS0 1 P
`
`Table 1 - Dedicated resource allocation IE format
`Size
`
`Notes
`
`Syntax
`Dedicated resource allocation IE()
`Extended DIUC
`Length
`Num Allocations
`For
`.
`i<Num_Allocations;i++)
`{
`
`(i=O;
`
`CID
`Duration(d)
`
`4 bits
`4 bits
`4 bits
`
`16 bits
`3 bits
`
`0x09
`Length in bytes
`Number of allocations in this IE
`
`The allocation is valid for 10 x 2°
`frame starting from the next frame
`If d =0b0OO,
`the dedicated
`allocation is de-allocated
`If d -- Obl 11,
`the dedicated
`resource shall be valid µntil the BS
`to de-allocate
`commands
`the
`dedicated allocation
`
`If (d!=000)
`{
`
`DIUC
`OFDMA svmboLoffset
`Subchannel offset
`Boosting
`No. OFDMA svmbols
`No. subchannels
`Repetition Coding Indication
`Period(p)
`
`4 bits
`8 bits
`6 bits
`3 bits
`8 bits
`6 bits
`2 bits
`2 bits
`
`}
`
`}
`
`l
`
`_Wherein:
`
`The DL resource region is dedicated
`to a MSS in every 2Pth frame
`
`Num_Allocations
`Number of allocations in this lE
`Duration(d)
`The allocation is valid for 10 x 2dframes starting from the next frame
`If d =0bOO0, the dedicated allocation is de-allocated
`If d = Obtll, the dedicated resource is valid until the BS commands to de-allocate the
`dedicated allocation
`
`Period(p)
`The DL resource region is dedicated to a MSS in every zPth frame
`5
`
`
`
`Attorney Docket No. 17399ROUS0IP
`
`In accordance with an embodiment of the invention Table 2 shows·an UL MAP IE format that may be used by a
`BS to allocate dedicated UL resource allocations to one or more Mobile Subscriber Stations (MSSs) and to de(cid:173)
`allocate/modify an existing allocation.
`
`Table 2 - Dedicated resource allocation IE format
`
`Syntax
`Dedicated resource allocation IBO
`Extended UIUC
`Length
`Num Allocations
`For
`i<Num Allocations;i++)
`{
`
`(i=O;
`
`CID
`Duration(d)
`
`4 bits
`4 bits
`4 bits
`
`16 bits
`3 bits
`
`Size
`
`Notes
`
`Ox09
`Length in bytes
`Number of allocations in this lE
`
`I
`
`The allocation is valid for 10 x 2°
`frame starting from the next frame.
`If d =0bOO0,
`the dedicated
`allocation is de-allocated
`If d -- 0bll l,
`the dedicated
`resource shall be valid until the BS
`commands
`to
`de-allocate
`the
`dedicated allocation
`
`If (d!=OO0)
`{
`
`UIUC
`OFDMA svmbol offset
`Subchannel offset
`Boosting
`No. OFDMA symbols
`No. subchannels
`Repetition Coding Indication
`Period(p)
`
`4 bits
`8 bits
`6 bits
`3 bits
`8 bits
`6 bits
`2 bits
`2 bits
`
`.
`
`~
`
`}
`
`}
`
`}
`
`The UL resource region is dedicated
`to a MSS in every 2Pth frame
`
`Wherein:
`Num_Allocations
`Number of a1locations in this IE
`Duration(d)
`The allocation is valid for 10 x 2d frames starting from the next frame
`If d ==0b000, the dedicated allocation is de-allocated
`6
`
`Copy provided by USPTO from the IFW Image Database on 05/12/2005
`
`
`
`If d == Ob 111, the dedicated resource is valid until the BS commands to de-allocate the
`dedicated allocation
`Period(p}
`The UL resource region is dedicated to a MSS in every 2Pth frame
`
`/
`
`Attorney Docket No. 17399ROUS0JP
`
`With reference to Figure 1, a base station controller (BSC) 10 controls wireless communications within multiple
`c_ells 12, which are served by corresponding base stations (BS) 14. In general, each base station 14 facilitates
`communications using OFDM with mobile terminals 16, which are within the cell 12 associated with the
`
`c-orresponding base station 14. The movement of the mobile terminals 16 in relation to the base stations 14
`
`results in significant fluctuation in channel conditions. As illustrated, the base stations 14 and mobile terminals
`
`16 may include multiple antennas to provide spatial diversity for communications.
`
`A high level overview of the mobile terminals 16 and base stations 14 of the present invention is provided prior
`
`to delving into the structural and functional details of the preferred embodiments. With reference to Figure 2, a
`
`base station 14 configured according to one embodiment of the present invention is illustrated: The base
`station 14 generally includes a control system 20, a baseband processor 22, transmit circuitry 24, receive
`circuitry 26, multiple antennas 28, and a network interface 30. The receive circuitry 26 receives radio
`
`frequency signals bearing information from one or more remote transmitters provided by mobile terminals 16
`
`(illustrated in Figure 3). Preferably, a low noise amplifier and a filter (not shown) cooperate to amplify and
`remove broadband interference from the signal for processing. Downconversion and digitization circuitry (not
`
`shown) will then downconvert the filtered, received signal to an intermediate or baseband frequency signal,
`
`which is then digitized into one or more digital streams.
`
`The baseband processor 22 processes the digitized received signal to extract the information or data bits
`~onveyed in the received signal. This processing typically comprises demodulation, decoding, and error
`
`correction operations. As such, the baseband processor 22 is generally implemented in one or more digital
`signal processors (DSPs) or application-specific integrated circuits (ASICs). The received information is then
`
`sent across a wireless network via the network interface 30 or transmitted to another mobile terminal 16
`
`serviced by the base station 14.
`
`On the transmit side, the baseband processor 22 receives digitized data, which may represent voice, data, or
`
`control information, from the network interface 30 under the control of control system 20, and encodes the data
`
`for transmission. The encoded data is output to the transmit circuitry 24, where it is modulated by a carrier
`
`7
`
`Copy provided by USPTO from the IFW lma!le Database on 05/12/2005
`
`
`
`signal having a desired transmit frequency or frequencies. A power amplifier (not shown) will amplify the
`
`modulated carrier signal to a level appropriate for transmission, and deliver the modulated carrier signal to the
`
`antennas 28 through a matching network (not shown). Modulation and processing details are described in
`
`greater detail below.
`
`Attorney Docket No. l 7399ROUS0 1 P
`
`With reference to Figure 3, a mobile terminal 16 configured according to one embodiment of the present
`
`invention is illustrated. Similarly to the base station 14, the mobile terminal 16 will include a control system 32,
`
`a baseband processor 34, transmit circuitry 36, receive circuitry 38, multiple antennas 40, and user interface
`
`circuitry 42. The receive circuitry 38 receives radio frequency signals bearing information from one or more
`
`base stations 14. Preferably, a low noise amplifier and a filter (not shown) cooperate to amplify and remove
`
`broadband interference from the signal for processing. Downconversion and digitization circuitry (not shown)
`
`will then downconvert the filtered, received signal to an intermediate or baseband frequency signal, which is
`
`then digitized into one or more digital streams.
`
`The baseband processor 34 processes the digitized received signal to extract the information or data bits
`
`conveyed in the received signal. This processing typically comprises demodulation, decoding, and error
`
`correction operations, as will be discussed on greater detail below. The baseband processor 34 is generally
`
`implemented in one or more digital signal processors (DSPs) and application specific integrated circuits
`
`(ASICs).
`
`For transmission, the baseband processor 34 receives digitized data, which may represent voice, data, or control
`
`information, from the control system 32, which it encodes for transmission. The encoded data is output to the
`
`transmit circuitry 36, where it is used by a modulator to modulate a carrier signal· that is at a desired transmit
`
`frequency or frequencies. A power amplifier (not shown) will amplify the modulated carrier signal to a level
`
`~appropriate for transmission, and deliver the modulated carrier signal to the antennas 40 through a matching
`network (not shown). Various modulation and processing techniques available to those skilled in the art are
`.
`applicable to the present invention.
`
`In OFDM modulation, the transmission band is divided into multiple, orthogonal carrier waves. Each carrier
`
`wave is modulated according to the digital data to be transmitted. Because OFDM divides the transmission
`
`band into multiple carriers, the bandwidth per carrier decreases and the modulation time per carrier increases.
`
`Since the multiple carriers are transmitted in parallel, the transmission rate for the digital data, or symbols, on
`
`any given carrier is lower than when a single carrier is used.
`8
`
`Copy provided by USPTO from the IFW Image Database on 05112/2005
`
`
`
`Attorney Docket No. 17399ROUS0 IP
`
`OFDM modulation requires the performance of an Inverse Fast Fourier Transform (lFFT) on the information to
`
`be transmitted. For demodulation, the performance of a Fast Fourier Transform (FFT) on the received signal is
`required to recover the transmitted information. In practice, the IFFf and FFT are provided by digital signal
`processing carrying out an Inverse Discrete Fourier Transform (IDFT) and Discrete Fourier Transform (DFf),
`
`respectively. Accordingly, the characterizing feature of OFDM modulation is that orthogonal carrier waves are
`
`generated for multiple bands within a transmission channel. The modulated signals are digital signals having a
`
`relatively low transmission rate and capable of staying within their respective bands. The individual carrier
`•
`waves are not modulated directly by the digital signals. Instead, all carrier waves are modulated at once by
`IFFT processing.
`
`In the preferred embodiment, OFDM is used for at least the downlink transmission from the base stations 14 to
`
`the mobile terminals 16.
`
`Each base station 14 is equipped with n transmit antennas 28, and each mobile
`
`terminal 16 is equipped with m receive antennas 40. Notably, the respective antennas can be used for reception
`
`and transmission using appropriate duplexers or switches and are so labeled only for clarity.
`
`With reference to Figure 4, a logical OFDM transmission architecture is provided according to one
`
`embodiment. Initially, the base station controller IO will send data to be transmitted to various mobile
`
`terminals 16 to the base station 14. The base station 14 may use the CQis associated with the mobile terminals
`
`to schedule the data for transmission as well as select appropriate coding and modulation for transmitting the
`
`scheduled data. The CQis may be directly from the mobile terminals 16 or determined at the base station 14
`based on information provided by the mobile terminals 16. In either case, the CQI for each mobile terminal 16
`
`is a function of the degree to which the channel amplitude (or response) varies across the OFDM frequency
`
`band.
`
`The scheduled data 44, which is a stream of bits, is scrambled in a manner reducing the peak-to-average power
`
`ratio associated with the data using data scrambling logic 46. A cyclic redundancy check (CRC) for the
`
`scrambled data is determined and appended to the scrambled data using CRC adding logic 48. Next, channel
`
`coding is performed using channel encoder logic 50 to effectively add redundancy to the data to facilitate
`
`recovery and error correction at the mobile terminal 16. Again, the channel coding for a particular mobile
`
`terminal 16 is based on the CQI. The channel encoder logic 50 uses known Turbo encoding techniques in one
`
`embodiment. The encoded data is then processed by rate matching logic 52 to compensate for the data
`
`expansion associated with encoding.
`
`9
`
`Copy orovided bv USPTO from the IFW Im~~" l"\p•~"-~"" "n '1.<;1-1?1?"""
`
`
`
`Attorney Docket No. 17399ROUS01P
`
`Bit interleaver logic 54 systematically reorders the bits in the encoded data to minimize the loss of consecutive
`
`data bits. The resultant data bits are systematically mapped into corresponding symbols depending on the
`
`chosen baseband modulation by mapping logic 56. Preferably. Quadrature Amplitude Modulation (QAM) or
`
`Quadrature Phase Shift Key (QPSK) modulation is used. The degree of modulation is preferably chosen based
`
`on the CQI for the particular mobile terminal. The symbols may be systematically reordered to further bolster
`
`the immunity of the transmitted signal to periodic data loss caused by frequency selective fading using symbol
`
`interleaver logic 58.
`,
`
`At this point, groups of bits have been mapped into symbols representing locations in an amplitude and phase
`
`consteUation. When spatial diversity is desired, blocks of symbols are then processed by space-time block
`
`code (STC) encoder logic 60, which modifies the symbols in a fashion making the transmitted signals more
`
`resistant to interference and more readily decoded at a mobile terminal 16. The STC encoder logic 60 will
`
`process the incoming symbols and provide n outputs corresponding to the number of transmit antennas 28 for
`'
`the base station 14. The control system 20 and/or baseband processor 22 will provide a mapping control signal
`
`to control STC encoding. At this point, assume the symbols for then outputs are representative of the data to
`
`be transmitted and capable of being recovered by the mobile terminal 16. See A.F. Naguib, N. Seshadri, and
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`A.R. Calderbank, "Applications of space-time codes and interference suppression for high capacity and high
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`data rate wireless systems," Thirty-Second Asilomar Conference on Signals, Systems & Computers, Volume 2,
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`pp. 1803-1810, 1998, which is incorporated herein by reference in its entirety.
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`For the present example, assume the base station 14 has two antennas 28 (n=2) and the STC encoder logic 60
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`provides two output streams of symbols. Accordingly, each of the symbol streams output by the STC encoder
`logic 60 is sent to a corresponding IFFr processor 62, illustrated separately for ease of understanding. Those
`• skilled in the art will recognize that one or more processors may be used to provide such digital signal
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`processing, alone or in combination with other processing described herein. The IFFT processors 62 will
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`preferably operate on the respective symbols to provide an inverse Fourier Transform. The output of the IFFT
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`processors 62 provides symbols in the time domain. The time domain symbols are grouped into frames, which
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`are associated with a prefix by like insertion logic 64. Each of the resultant signals is up-converted in the
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`digital domain to an intermediate frequency and converted to an analog signal via the corresponding digital up(cid:173)
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`conversion (DUC) and digital-to-analog (DIA) conversion circuitry 66. The resultant (analog) signals are then
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`simultaneously modulated at the desired RF frequency, amplified, and transmitted via the RF circuitry 68 and
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`antennas 28. Notably, pilot signals known by the intended mobile terminal 16 are scattered among the sub-
`IO
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`carriers. The mobile terminal 16, which is discussed in detail below, will use the pilot signals for channel
`estimation.
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`Attorney Docket No. 17399ROUS0IP
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`Reference is now made to Figure 5 to illustrate reception of the transmitted signals by a mobile terminal 16.
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`Upon arrival of the transmitted signals at each of the antennas 40 of the mobile terminal 16, the respective
`signals are demodulated and amplified by corresponding RF circuitry 70. For the sake of conciseness and
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`clarity, only one of the two receive paths is described and illustrated in detail. Analog-to-digital (AID)
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`,converter and down-conversion circuitry 72 digitizes and downconverts the analog signal for digital processing.
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`The resultant digitized signal may be used by automatic gain control circuitry (AGC) 74 to control the gain of
`the amplifiers in the RF circuitry 70 based on the received signal level.
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`Initially, the digitized signal is provided to synchronization logic 76, which includes coarse synchronization
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`logic 78, which buffers several OFDM symbols and calculates an auto-correlation between the two successive
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`OFDM symbols. A resultant time index corresponding to the maximum of the correlation result determines a
`fine synchronization search window, which is used by fine synchronization logic 80 to determine a precise
`framing starting position based on the headers. The output of the fine synchronization logic 80 facilitates
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`frame acquisition by frame alignment logic 84. Proper framing alignment is important so that subsequent FFI'
`processing provides an accurate conversion from the time to the frequency domain. The fine synchronization
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`algorithm is based on the correlation between the received pilot signals carried by the headers and a local copy
`of the known pilot data. Once frame alignment acquisition occurs, the prefix of the OFDM symbol is removed
`with prefix removal logic 86 and resultant samples are sent to frequency offset correction logic 88, which
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`compensates for the system frequency offset caused by the unmatched local oscillators in the transmitter and the
`receiver. Preferably, the synchronization logic 76 includes frequency offset and clock estimation logic 82,
`which is based on the headers to help estimate such effects on the transmitted signal and provide those
`"' estimations to the correction logic 88 to properly process OFDM symbols.
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`At this point, the OFDM symbols in the time domain are ready for conversion to the frequency domain using
`FFf processing logic 90. The results are frequency domain symbols, which are sent to processing logic 92.
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`The processing logic 92 extracts the scattered pilot signal using scattered pilot extraction logic 94, determines a
`channel estimate based on the extracted pilot signal using channel estimation logic 96, and provides channel
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`responses for all sub-carriers using channel reconstruction logic 98. In order to determine a channel response
`for each of the sub-carriers, the pilot signal is essentially multiple pilot symbols that are scattered among the
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`data symbols throughout the OFDM sub-carriers in a known pattern in both time and frequency. Figure 6
`11
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`Copy provided by USPTO from the IFW lmaoe Database o" Ol'i/~?/?nn.o;
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`
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`Attorney Docket No. 17399ROUS01 P
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`illustrates an exemplary scattering of pilot symbols among available sub-carriers over a given time and
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`frequency plot in an OFDM environment. Continuing with Figure 5, the processing logic compares the
`received pilot symbols with the pilot symbols that are expected in certain sub-carriers at certain times to
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`determine a channel response for the sub-carriers in which pilot symbols were transmitted. The results are
`interpolated to estimate a channel response for most, if not all, of the remaining sub-carriers for which pilot
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`symbols were not provided. The actuaJ and interpolated channel responses are used to estimate an overall
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`channel response, which includes the channel responses for most, if not all, of the sub-carriers in the OFDM
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`channel.
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`The frequency domain symbols and channel reconstruction information, which are derived from the channel
`responses for each receive path are provided to an STC decoder iOO, which provides STC decoding on both
`received paths to recover the transmitted symbols. The channel reconstruction information provides
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`equalization information to the STC decoder 100 sufficient to remove the effects of the transmission channel
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`when processing the respective frequency domain symbols
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`The recovered symbols are placed back in o_rder using symbol de-interleaver logic 102, which corresponds to
`the symbol interleaver logic 58 of the transmitter. The de-interleaved symbols are then demodulated or de(cid:173)
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`mapped to a corresponding bitstream _using de-mapping logic 104. The bits are then de-interleaved using bit
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`de-interleaver logic 106, which corresponds to the bit interleaver logic 54 of the transmitter architecture. The
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`de-interleaved bits are then processed by rate de-matching logic 108 and presented to channel decoder logic 110
`to recover the initially scrambled data and the CRC checksum. Accordingly, CRC logic 112 removes the CRC
`checksum, checks the scrambled data in traditional fashion, and provides it to the de-scrambling logic 114 for
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`de-scrambling using the known base station de-scrambling code to recover the originally transmitted data 116.
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`·In parallel to recovering the data 116, a CQI, or at least information sufficient to create a CQI at the base station
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`14, is determined and transmitted to the base station 14. As noted above, the CQI in a preferred embodiment is
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`"a function of the carrier-to-interference ratio (CIR), as well as the degree to which the