August 2004
`
`doc.: IEEE 802.11-04/0923r0
`
`Date:
`
`Author:
`
`IEEE P802.11
`Wireless LANs
`ETRI proposal specification for IEEE 802.11 TGn
`
`August 13, 2004
`
`Heejung Yu, Taehyun Jeon, Sok-Kyu Lee,
`Myung-Soon Kim, Eun-young Choi, and Seung-Ku Hwang
`
`Electronics and Telecommunications Research Institute (ETRI)
`161 Gajeong-dong Yuseong-gu, Daejeon, 305-350, KOREA
`Phone : +82 42 860 1651
`Fax : +82 42 860 6732
`e-Mail: {heejung, thjeon, sk-lee, mskim75, eychoi, skhwang}@etri.re.kr
`
`Abstract
`The following is an IEEE 802.11 TGn physical layer specification proposed by ETRI. This document
`describes the physical layer specification of high data rate wireless LAN system targeting the maximum
`speed of 144Mbps in 20MHz bandwidth and 288Mbps in 40MHz bandwidth to achieve at least 100Mbps
`maximum throughput at the top of the MAC SAP (Service Access Point). Additionally, this specification
`has compatibility with IEEE 802.11a legacy-OFDM systems. For more cost effective implementation, 2
`transmit chains and dual band (two 20MHz bandwidth channels) scheme are utilized.
`
`Features of this high throughput wireless LAN specification include the followings:
` Compatible with the IEEE802.11a system
` Data rate in 20MHz bandwidth
`o 6,9,12,18,24,36,48,54 (IEEE 802.11a Legacy OFDM and optional STBC-OFDM modes)
`o 72,96,108, 128, 144Mbps (SDM-OFDM mode with 2 independent data streams, 128 and
`144Mbps are optional)
`o The above data rates are doubled in 40MHz bandwidth
` Bandwidth: 20 and 40MHz
` Multiple antennas: 2 transmit antennas (3 receive antennas are recommended. To utilized all
`antennas, implementer can use transmit antenna selection (2 out of 3 antennas).)
` Modulation: Legacy-OFDM, MIMO-OFDM including SDM-OFDM and STBC-OFDM
`Forward error correction: Rate variable punctured convolutional code
`
`
`Submission
`
`page 1
`
`Heejung Yu, ETRI
`
`HUAWEI EXHIBIT 1023
`HUAWEI VS. SPH
`
`000001
`
`

`
`August 2004
`
`Contents
`
`doc.: IEEE 802.11-04/0923r0
`
`4. Abbreviations and acronyms ................................................................................. 4
`20. MIMO-OFDM specification ............................................................................... 4
`20.1 Introduction ........................................................................................................................................... 4
`20.1.1 Scope .................................................................................................................................................. 4
`20.1.2 MIMO-OFDM PHY functions ........................................................................................................... 4
`20.1.2.1 PLCP sublayer ................................................................................................................................ 5
`20.1.2.2 PMD sublayer ................................................................................................................................. 5
`20.1.2.3 PHY management entity (PLME) ................................................................................................... 5
`20.1.2.4 Service specification method .......................................................................................................... 5
`20.2 MIMO-OFDM PHY specific service parameter list ............................................................................. 5
`20.2.1 Introduction ........................................................................................................................................ 5
`20.2.2 TXVECTOR parameters .................................................................................................................... 5
`20.2.2.1 TXVECTOR LENGTH .................................................................................................................. 6
`20.2.2.2 TXVECTOR DATARATE ............................................................................................................. 6
`20.2.2.3 TXVECTOR BANDWIDTH .......................................................................................................... 6
`20.2.2.4 TXVECTOR MODE ...................................................................................................................... 6
`20.2.2.5 TXVECTOR SERVICE .................................................................................................................. 6
`20.2.2.6 TXVECTOR TXPWR_LEVEL ...................................................................................................... 7
`20.2.3 RXVECTOR parameters.................................................................................................................... 7
`20.2.3.1 RXVECTOR LENGTH .................................................................................................................. 7
`20.2.3.2 RXVECTOR RSSI .......................................................................................................................... 7
`20.2.3.3 RXVECTOR DATARATE ............................................................................................................. 8
`20.2.3.4 RXVECTOR BANDWIDTH ......................................................................................................... 8
`20.2.3.5 RXVECTOR MODE ...................................................................................................................... 8
`20.2.3.6 RXVECTOR SERVICE ................................................................................................................. 8
`20.3 MIMO-OFDM PLCP sublayer ............................................................................................................. 8
`20.3.1 Introduction ........................................................................................................................................ 8
`20.3.2 PLCP frame format ............................................................................................................................ 8
`20.3.2.1 Overview of the PPDU encoding process ....................................................................................... 9
`20.3.2.2 RATE-dependent parameters ........................................................................................................ 11
`20.3.2.3 Timing related parameters ............................................................................................................ 11
`20.3.3 PLCP Preambles .............................................................................................................................. 11
`20.3.3.1 Preamble for single antenna and single band mode ...................................................................... 12
`20.3.3.2 Preamble for dual antenna and single band mode ......................................................................... 12
`20.3.3.3 Preamble for single antenna and dual band mode ......................................................................... 13
`20.3.3.4 Preamble for dual antenna and dual band mode ........................................................................... 14
`20.3.4 Signal field (SIGNAL) ..................................................................................................................... 15
`20.3.4.1 Data rate(RATE) and antenna mode(ANTENNA) ....................................................................... 16
`20.3.4.2 PLCP length field (LENGTH) ...................................................................................................... 16
`20.3.4.3 Parity (P), and Signal tail (SIGNAL TAIL) .................................................................................. 17
`20.3.4.4 SIGNAL transmission for single antenna and single band mode .................................................. 17
`20.3.4.5 SIGNAL transmission for dual antenna and single band mode .................................................... 17
`20.3.4.6 SIGNAL transmission for single antenna and dual band mode .................................................... 17
`20.3.4.7 SIGNAL transmission for dual antenna and dual band mode ....................................................... 18
`20.3.5 DATA field ...................................................................................................................................... 18
`20.3.5.1 Service field (SERVICE) .............................................................................................................. 18
`20.3.5.2 PPDU tail bit field (TAIL) ............................................................................................................ 18
`20.3.5.3 Pad bits (PAD) .............................................................................................................................. 18
`20.3.5.4 Data arbitrator for two channel (dual band) .................................................................................. 19
`20.3.5.5 PLCP DATA scrambler and descrambler ..................................................................................... 19
`20.3.5.6 Convolutional encoder .................................................................................................................. 19
`20.3.5.7 Data interleaving ........................................................................................................................... 19
`20.3.5.8 Subcarrier modulation mapping .................................................................................................... 20
`20.3.5.9 Antenna Arbitration for legacy OFDM mode ............................................................................... 21
`20.3.5.10 Antenna Arbitration for STBC-OFDM mode ............................................................................. 22
`
`Submission
`
`page 2
`
`Heejung Yu, ETRI
`
`HUAWEI EXHIBIT 1023
`HUAWEI VS. SPH
`
`000002
`
`

`
`August 2004
`
`
`
`doc.: IEEE 802.11-04/0923r0
`
`20.3.5.11 Antenna Arbitration for SMD-OFDM mode ............................................................................... 22
`20.3.5.12 Pilot subcarriers ........................................................................................................................... 23
`20.3.5.13 OFDM modulation....................................................................................................................... 23
`20.3.6 Clear channel assessment (CCA) ...................................................................................................... 24
`20.3.7 PLCP data modulation and modulation rate change ......................................................................... 24
`20.3.8 PMD operating specification (general) ............................................................................................. 24
`20.3.8.1 Outline description......................................................................................................................... 24
`20.3.8.2 Regulatory requirements ................................................................................................................ 25
`20.3.8.3 Operating channel frequencies ....................................................................................................... 25
`20.3.8.4 Transmit and receive in-band and out-of-band spurious emissions ............................................... 25
`20.3.8.5 TX RF delay .................................................................................................................................. 26
`20.3.8.6 Slot time ......................................................................................................................................... 26
`20.3.8.7 Transmit and receive antenna port impedance ............................................................................... 26
`20.3.8.8 Transmit and receive operating temperature range ........................................................................ 26
`20.3.9 PMD transmit specifications ............................................................................................................. 26
`20.3.10 PMD receiver specifications ........................................................................................................... 26
`
`
`
`Submission
`
`page 3
`
`Heejung Yu, ETRI
`
`HUAWEI EXHIBIT 1023
`HUAWEI VS. SPH
`
`000003
`
`

`
`August 2004
`
`
`
`doc.: IEEE 802.11-04/0923r0
`
`4. Abbreviations and acronyms
`
`Insert the following acronyms alphabetically in the list in Clause 4:
`
`MIMO
`SDM
`STBC
`
`
`
`
`
`Multiple Input Multiple Output
`Spatial Division Multiplexing
`Space-Time Block Code
`
`
`
`20. MIMO-OFDM specification
`
`
`
`20.1 Introduction
`
`This clause specifies rate extension of OFDM PHY systems of Clause 17. The target of this PHY specification is to
`achieve at least 100Mbps maximum throughput at the top of the MAC SAP. For this purpose, this specification
`provides maximum of 144Mbps and 288Mbps in 20 and 40MHz bandwidth, respectively.
`
`The legacy OFDM PHY modes with single transmit antenna and 20MHz bandwidth in Clause 17 provides a
`wireless LAN data pay load communication capabilities of 6, 9, 12, 18, 24, 36, 48 and 54Mbps. As the demands for
`high-speed data transmission in home, enterprise and hot-spot environments have increased, the new technology
`capable of hundreds Mbps data transmission is required. As a solution for this target, the new PHY modes are
`suggested using 2 transmit antennas and dual band modes, which can offer maximum of 288Mbps. In 20MHz
`bandwidth case, data rates of 72, 96, 108, 128 and 144 Mbps are added. If dual band (40MHz bandwidth) is
`employed, the PHY supports 12, 18, 24, 36, 48, 72, 96 and 108 Mbps which transmit single data stream through 1
`transmit antenna and 144, 192, 216, 256 and 288Mbps which transmit two data streams simultaneously through 2
`transmit antennas.
`
`In addition to these high data rate SDM-OFDM mode, further reliability improvement can be achieved by using the
`well-known Alamouti space-time block code in the transmitter in STBC-OFDM mode.
`
`
`
`20.1.1 Scope
`
`This subclause describes the PHY services provided to the IEEE 802.11 wireless LAN using MIMO-OFDM
`technologies, which is compatible with legacy IEEE 802.11a system. The PHY layer consists of two protocol
`functions, as follows:
`
`
`a) A PHY convergence function, which adapts the capabilities of the physical medium dependent (PMD)
`system to the PHY services. This function is supported by the physical layer convergence procedure
`(PLCP), which defines a method of mapping the IEEE 802.11 PHY sublayer service data units (PSDU)
`into a framing format suitable for sending and receiving user data and management information between
`two or more stations using the associated PMD system.
`
`
`b) A PMD system whose function defines the characteristics and method of transmitting and receiving data
`through a wireless medium between two or more stations, each using the OFDM system.
`
`
`
`20.1.2 MIMO-OFDM PHY functions
`
`The MIMO-OFDM PHY architecture is depicted in the reference model shown in Figure 11 of IEEE Std 802.11.
`1999 Edition (5.8). The MIMO-OFDM PHY contains three functional entities: the PMD function, the PHY
`convergence function, and the layer management function. Each of these functions is described in detail in 20.1.2.1
`through 20.1.2.4.
`
`The MIMO-OFDM PHY service is provided to the MAC through the PHY service primitives described in Clause 12
`of IEEE Std 802.11, 1999 Edition.
`
`
`Submission
`
`page 4
`
`Heejung Yu, ETRI
`
`HUAWEI EXHIBIT 1023
`HUAWEI VS. SPH
`
`000004
`
`

`
`August 2004
`
`
`
`doc.: IEEE 802.11-04/0923r0
`
`
`20.1.2.1 PLCP sublayer
`
`In order to allow the IEEE 802.11 MAC to operate with minimum dependence on the PMD sublayer, a PHY
`convergence sublayer is defined. This function simplifies the PHY service interface to the IEEE 802.11 MAC
`services.
`
`
`
`20.1.2.2 PMD sublayer
`
`The PMD sublayer provides a means to send and receive data between two or more stations. This clause is
`concerned with the legacy OFDM and MIMO-OFDM modulation.
`
`
`
`20.1.2.3 PHY management entity (PLME)
`
`The PLME performs management of the local PHY functions in conjunction with the MAC management entity.
`
`
`
`20.1.2.4 Service specification method
`
`The models represented by figures and state diagram are intended to be illustrations of the functions provided. It is
`important to distinguish between a model and a real implementation. The models are optimized for simplicity and
`clarity of presentation; the actual method of implementation is left to the discretion of the IEEE 802.11 MIMO-
`OFDM PHY compliant developer.
`
`The service of a layer or sublayer is the set of capabilities that it offers to a user in the next high layer (or sublayer).
`Abstract services are specified here by describing the service primitives and parameters that characterize each
`service. This definition is independent of any particular implementation.
`
`
`
`20.2 MIMO-OFDM PHY specific service parameter list
`
`
`
`20.2.1 Introduction
`
`The architecture of the IEEE 802.11 MAC is intended to be PHY independent. Some PHY implementations require
`medium management state machines running in the MAC sublayer in order to meet certain PMD requirements.
`These PHY-dependent MAC state machines reside in a sublayer defined as the MAC sublayer management entity
`(MLME). In certain PMD implementations, the MLME may need to interact with the PLME as part of the normal
`PHY SAP primitives. These interactions are defined by the PLME parameter list currently defined in the PHY
`service primitives as TXVECTOR and RXVECTOR. The list of these parameters, and the values they may represent,
`are defined in the specific PHY specifications for each PMD. This subclause addresses the TXVECTOR and
`RXVECTOR for the legacy OFDM and MIMO-OFDM PHY.
`
`
`
`20.2.2 TXVECTOR parameters
`
`The parameters in Table 124A are defined as a part of the TXVECTOR parameter list in the PHY-
`TXSTART.request service primitive.
`
`
`Parameter
`LENGTH
`
`DATARATE
`
`Submission
`
`Table 124A – TXVECTOR parameters
`Associate primitive
`Value
`PHY_TXSTART.request
`1-4095. This parameter means the length per 20MHz
`(TXVECTOR)
`band.
`In dual band case, a real data length shall be
`2LENGTH.
`PHY_TXSTART.request Data rate corresponding to one 20MHz bandwidth.
`
`page 5
`
`Heejung Yu, ETRI
`
`HUAWEI EXHIBIT 1023
`HUAWEI VS. SPH
`
`000005
`
`

`
`August 2004
`
`
`
`doc.: IEEE 802.11-04/0923r0
`
`(TXVECTOR)
`
`BANDWIDTH
`
`PHY_TXSTART.request
`(TXVECTOR)
`
`MODE
`
`PHY_TXSTART.request
`(TXVECTOR)
`
`SERVICE
`
`PHY_TXSTART.request
`(TXVECTOR)
`TXPWR_LEVEL PHY_TXSTART.request
`(TXVECTOR)
`
`(Real data rates are doubled in case of 40MHz dual
`band.)
`
`6, 9, 12, 18, 24, 36, 48, and 54 (Both legacy and
`STBC-OFDM are possible. STBC-OFDM is optional)
`
`72, 96, 108, 128 and 144 (SDM-OFDM, 128 and
`144Mbps are optional.)
`PHY can use consecutive two 20MHz bands for
`higher data rate.
`This is information about channel usage.
`Lower band (channel 0), Upper band (channel 1), and
`Dual band
`The transmission scheme is used for the transmission
`of this PSDU.
`Legacy OFDM, STBC-OFDM and SDM-OFDM.
`Scrambler initialisation; 7 null bits + 9 reserved null
`bits
`1-8
`This power level represents the total transmit power of
`all transmit antennas.
`
`
`
`20.2.2.1 TXVECTOR LENGTH
`
`The allowed values for the LENGTH parameter are in the range of 1–4095. This parameter is used to indicate the
`number of octets in the MPDU which the MAC is currently requesting the PHY to transmit in one 20MHz band. If
`the dual band mode (40MHz) is used, the total number of transmitted data is 2LENGTH octets. This value is used
`by the PHY to determine the number of octet transfers that will occur between the MAC and the PHY after
`receiving a request to start the transmission.
`
`
`
`20.2.2.2 TXVECTOR DATARATE
`
`The DATARATE parameter describes the bit rate at which the PLCP shall transmit the PSDU. Its value can be any
`of the rates defined in Table 124A. Real data rates are determined by the DATARATE and BANDWIDTH. In case
`of single band (Upper or Lower channel), data rates of 6, 9, 12, 18, 24, 36, 48, 54, 72, 96, 108, 128, and 144 shall be
`supported. Moreover, 128 and 144Mbps are optional data rates. In case of dual band, data rates are doubled.
`
`
`
`20.2.2.3 TXVECTOR BANDWIDTH
`
`The BANDWIDTH parameter indicates the utilized bandwidth by PHY to transmit the PSDU. Its value shall
`represent lower, upper, or dual band. According to this information, real data rate shall be varied as mentioned in the
`above subclause.
`
`
`
`20.2.2.4 TXVECTOR MODE
`
`This value, MODE, shall represent the transmission mode type. The allowed types of the MODE are legacy OFDM,
`STBC-OFDM or SDM-OFDM where STBC-OFDM is optional.
`
`
`
`20.2.2.5 TXVECTOR SERVICE
`
`The SERVICE parameter consists of 7 null bits used for the scrambler initialization and 9 null bits reserved for
`future use.
`
`
`
`Submission
`
`page 6
`
`Heejung Yu, ETRI
`
`HUAWEI EXHIBIT 1023
`HUAWEI VS. SPH
`
`000006
`
`

`
`August 2004
`
`
`
`doc.: IEEE 802.11-04/0923r0
`
`20.2.2.6 TXVECTOR TXPWR_LEVEL
`
`The allowed values for the TXPWR_LEVEL parameter are in the range from 1–8. This parameter is used to indicate
`which of the available TxPowerLevel attributes defined in the MIB shall be used for the current transmission. If two
`transmit antennas are used for PSDU transmission, TXPWR_LEVEL means the total power of transmitted signal
`through both antennas.
`
`20.2.3 RXVECTOR parameters
`
`The parameter listed in Table 124B are defined as a part of the RXVECTOR parameter list in the PHY-
`RXSTART.indicate service primitive.
`
`
`
`
`Parameter
`LENGTH
`
`RSSI
`
`DATARATE
`
`BANDWIDTH
`
`MODE
`
`SERVICE
`
`PHY-RXSTART.indicate
`(RXVECTOR)
`
`PHY-RXSTART.indicate
`(RXVECTOR)
`
`Table 124B – RXVECTOR parameters
`Associate primitive
`Value
`PHY-RXSTART.indicate
`1-4095. This parameter means the length per 20MHz
`(RXVECTOR)
`band.
`In dual band case, a real data length shall be
`2LENGTH.
`0-RSSI maximum.
`It has the same number of values as the number of
`receive antennas.
`Data rate corresponding to one 20MHz bandwidth.
`(Real data rates are doubled in case of 40MHz dual
`band.)
`6, 9, 12, 18, 24, 36, 48, and 54 (Both legacy and
`STBC-OFDM
`are possible. STBC-OFDM
`is
`optional)
`
`72, 96, 108, 128 and 144 (SDM-OFDM, 128 and
`144Mbps are optional.)
`PHY can use consecutive two 20MHz bands for
`higher data rate.
`This is information about channel usage.
`Lower band (channel 0), Upper band (channel 1), and
`Dual band
`The mode used for the transmission of this PSDU
`Legacy OFDM, STBC-OFDM and SDM-OFDM.
`Null
`
`PHY-RXSTART.indicate
`(RXVECTOR)
`
`PHY-RXSTART.indicate
`(RXVECTOR)
`PHY-RXSTART.indicate
`(RXVECTOR)
`
`
`
`20.2.3.1 RXVECTOR LENGTH
`
`The allowed values for the LENGTH parameter are in the range from 1–4095. This parameter is used to indicate the
`value contained in the LENGTH field which the PLCP has received in the PLCP header per 20MHz band. If the
`dual band mode (40MHz) is used, the total number of received data is 2LENGTH octets. The MAC and PLCP will
`use this value to determine the number of octet transfers that will occur between the two sublayers during the
`transfer of the received PSDU.
`
`
`
`20.2.3.2 RXVECTOR RSSI
`
`The allowed values for the receive signal strength indicator (RSSI) parameter are in the range from 0 to RSSI
`maximum. This parameter is a measure by the PHY sublayer of the energy observed at the antenna used to receive
`the current PPDU. RSSI shall be measured during the reception of the PLCP preamble. RSSI is intended to be used
`in a relative manner, and it shall be a monotonically increasing function of the received power. In case of multiple
`receive antennas, each antenna has its own RSSI value.
`
`Submission
`
`page 7
`
`Heejung Yu, ETRI
`
`HUAWEI EXHIBIT 1023
`HUAWEI VS. SPH
`
`000007
`
`

`
`August 2004
`
`
`
`doc.: IEEE 802.11-04/0923r0
`
`
`
`
`
`20.2.3.3 RXVECTOR DATARATE
`
`DATARATE shall represent the data rate at which the current PPDU was received for the single 20MHZ band. The
`allowed values of the DATARATE are 6, 9, 12, 18, 24, 36, 48, and 54 for legacy OFDM or STBC-OFDM modes.
`For SDM-OFDM mode, 72, 96, 108, 128, and 144Mbps are the supported data rates.
`
`20.2.3.4 RXVECTOR BANDWIDTH
`
`The BANDWIDTH parameter indicates the utilized bandwidth of current PPDU. Its value shall represent lower,
`upper, or dual band. According to this information, real data rate shall be varied
`
`
`
`20.2.3.5 RXVECTOR MODE
`
`This value, MODE, shall represent the transmission scheme. The allowed types of the MODE are legacy OFDM,
`STBC-OFDM, and SDM-OFDM.
`
`
`
`20.2.3.6 RXVECTOR SERVICE
`
`The SERVICE field shall be null.
`
`
`
`20.3 MIMO-OFDM PLCP sublayer
`
`
`
`20.3.1 Introduction
`
`This subclause provides a convergence procedure in which PSDUs are converted to and from PPDUs. During
`transmission, the PSDU shall be provided with a PLCP preamble and header to create the PPDU. At the receiver, the
`PLCP preamble and header are processed to aid in demodulation and delivery of the PSDU.
`
`
`
`20.3.2 PLCP frame format
`
`The frame structure of the transmit signal is shown in Figure 154A. The frame structure is the same as that of the
`IEEE802.11a to be compatible with the legacy systems (IEEE802.11a) except for the antenna bit and second long
`preambles. This frame structure allows for the legacy devices to demodulate the packet transmitted by MIMO-
`OFDM device. In both STBC-OFDM and SDM-OFDM modes, additional long preamble is appended after SIGNAL
`symbol to improve the channel estimation capability. In case that the legacy receiver detects MIMO-OFDM frame,
`it can decode up to the SIGNAL symbol and wait for the end of packet reception.
`The antenna bit in combination with a part of the rate information determines the transmission mode. The length
`field carries the information about the number of bytes in the PSDU to transmit per 20MHz bandwidth. The parity
`bit is the even parity for bits in rate, antenna, and length fields. The tail bits are 6 zero bits used to flush the decoder
`state. The SIGNAL symbol is coded with the rate 1/2 and the subcarriers are modulated with BPSK. The service
`field consists of 7 zero bits to initialize the descrambler in the receiver and 9 reserved service bits. The PSDU is the
`data requested to transmit from the MAC. The tail bits in the data field is 6 zero bits to make the decoder converge
`to a single state in the receiver. The pad bits, all zeros, are used to fill the unused subcarriers in the last OFDM
`symbol.
`
`When a single transmit antenna is used, the modulated signal of the preamble, header, and SIGNAL symbol is the
`same as that of IEEE802.11a. When two transmit antennas are used, half of the information of the preamble and
`SIGNAL symbol is transmitted through the antenna 0 and the other half through the antenna 1. When two channels
`are used (40MHz bandwidth), the same preamble and SINGAL symbol are transmitted through each 20MHz
`channel. For more detail, refer to the corresponding subclauses.
`
`
`Submission
`
`page 8
`
`Heejung Yu, ETRI
`
`HUAWEI EXHIBIT 1023
`HUAWEI VS. SPH
`
`000008
`
`

`
`August 2004
`
`
`
`doc.: IEEE 802.11-04/0923r0
`
`For a single antenna system, the data field is generated as in the IEEE802.11a. For the dual antenna system, the data
`field is generated independently for each antenna (SDM-OFDM) or according to the chosen STBC coding rule
`(STBC-OFDM). For the dual band systems, the data field for each channel is independently scrambled and encoded.
`The SIGNAL symbol does not carry any information about the channel usage. The receiver should decide if the
`signal is transmitted through 1 or 2 channels.
`
`
`P LC P H ead er
`
`R ate
`4 b its
`
`A ntenna
`1 b it
`
`Leng th
`12 b its
`
`P arity
`1 b it
`
`Tail
`6 b its
`
`S ervice
`16 b its
`
`P S D U
`
`Tail
`6 b its
`
`P ad b its
`
`C o d ed O FD M
`(B P S K , r= 1/2)
`
`C o d ed O FD M
`(R ate is g iven in S ig nal sym b o l)
`
`P ream b le
`12 sym b o ls
`
`S IG N A L
`O ne O FD M sym b o l
`
`D ata
`Variab le num b er o f O FD M sym b o ls
`
`16usec
`
`4 usec
`(a) Legacy OFDM PPDU frame format
`
`
`
`
`
`
`
`P LC P H ead er
`
`P LC P H ead er
`
`R ate
`4 b its
`
`A ntenna
`1 b it
`
`Leng th
`12 b its
`
`P arity
`1 b it
`
`Tail
`6 b its
`
`2 Lo ng
`seq uences
`
`S ervice
`16 b its
`
`P S D U
`
`Tail
`6 b its
`
`P ad b its
`
`C o d ed O FD M
`(B P S K , r= 1/2)
`
`C o d ed O FD M
`(R ate is g iven in S ig nal sym b o l)
`
`P ream b le
`12 sym b o ls
`
`S IG N A L
`O ne O FD M sym b o l
`
`2 Lo ng
`P ream b les
`
`D ata
`Variab le num b er o f O FD M sym b o ls
`
`16usec
`
`4 usec
`
`8 usec
`
`(b) STBC-OFDM and SDM-OFDM PPDU frame format
`
`Figure 154A – PPDU frame format
`
`20.3.2.1 Overview of the PPDU encoding process
`
`The encoding process is composed of many detailed steps, which are described fully in later subclauses, as noted
`below. The following overview intends to facilitate understanding the details described in these subclauses:
`
`
`a) Produce the PLCP preamble field, composed of 10 repetitions of a “short training sequence” (used for AGC
`convergence, timing acquisition, and coarse frequency acquisition in the receiver) and two repetitions of a
`“long training sequence” (used for channel estimation, fine frequency acquisition and band detection to
`determine which band, upper, lower or both bands, is used for PPDU transmission), preceded by a guard
`interval (GI). If 2 transmit antennas are used for STBC-OFDM and SDM-OFDM modes, antennas 0 (one
`antenna) carries only even subcarriers of legacy short and long sequences and antenna 1 (the other antenna)
`odd ones. In addition to this, another long preamble field is added for MIMO channel estimation after
`SIGNAL symbol in STBC-OFDM and SDM-OFDM modes. In this case, antenna 0 carries odd subcarriers
`of preambles and antenna 1 even ones. Refer to 20.3.3 for details.
`
`b) Produce the PLCP header field from the DATARATE, LENGTH, MODE and SERVICE fields of the
`TXVECTOR by filling the appropriate bit fields. The RATE, ANTENNA and LENGTH fields of the PLCP
`header are encoded by a convolutional code at a rate of R = 1/2, and are subsequently mapped onto a single
`BPSK encoded OFDM symbol, denoted as the SIGNAL symbol. In order to facilitate a reliable and timely
`detection of the RATE, ANTENNA and LENGTH fields, 6 “zero” tail bits are inserted into the PLCP
`header. The encoding of the SIGNAL field into an OFDM symbol follows the same steps for convolutional
`
`
`
`
`
`Submission
`
`page 9
`
`Heejung Yu, ETRI
`
`HUAWEI EXHIBIT 1023
`HUAWEI VS. SPH
`
`000009
`
`

`
`August 2004
`
`
`
`doc.: IEEE 802.11-04/0923r0
`
`encoding, interleaving, BPSK modulation, pilot insertion, Fourier transform, and prepending a GI as
`described subsequently for data transmission at 6 Mbits/s. The contents of the SIGNAL field are not
`scrambled. In case of STBC-OFDM and SDM-OFDM, SIGNAL field subcarriers are distributed to 2
`transmit antennas by the same rule of the first long preamble. Refer to 20.3.4 for details.
`
`c) Calculate from DATARATE field of the TXVECTOR the number of data bits per OFDM symbol (NDBPS),
`the coding rate (R), the number of bits in each OFDM subcarrier (NBPSC), and the number of coded bits per
`OFDM symbol (NCBPS). Refer to 20.3.4.1 for details.
`
`d) Append the PSDU to the SERVICE field of the TXVECTOR. Extend the resulting bit string with “zero”
`bits (at least 6 bits) so that the resulting length will be a multiple of NDBPS. Especially in STBC-OFDM, the
`resulting length should be a multiple of 2NDBPS because a pair of OFDM symbols (two consecutive
`OFDM symbols) is STBC encoded together. In case that dual band is used, the pad bits are added to each
`band frame in that the frame for each band is considered as independent to each other. The resulting bit
`string constitutes the DATA part of the packet for each 20MHz band. Refer to 20.3.5.3 for details.
`
`e)
`
`Initiate the scrambler with a pseudorandom non-zero seed, generate a scrambling sequence, and XOR it
`with the extended string of data bits. This scrambling is performed for each band. Therefore 2 scramblers
`are needed for dual band case and these two scramblers have the same seed. Refer to 20.3.5.5 for details.
`
`f) Replace the six scrambled “zero” bits following the “data” with six nonscrambled “zero” bits. (Those bits
`return the convolutional encoder to the “zero state” and are denoted as “tail bits.”) Refer to 20.3.5.2 for
`details.
`
`g) Encode the extended, scrambled data string with a convolutional encoder (R = 1/2). Omit (puncture) some
`of the encoder output string (chosen according to “puncturing pattern”) to reach the desired “coding rate.”
`Encoding process is also performed independently for each 20MHz band as in the case of scrambling
`process. Two bands have same coding rate in dual band mode. Refer to 20.3.5.6 for details.
`
`h) Divide the encode