July 2000 doc IEEE 802 11 00202 Frequency

July 2000 doc. : IEEE 802. 11 -00/202 Frequency Domain Modulators for 802. 11 b Mark Webster Intersil Corporation July 2000 Submission 1 Mark Webster, Intersil

July 2000 doc. : IEEE 802. 11 -00/202 Overview • Examine frequency domain modulator for 802. 11 1 and 2 Mbps Barker signaling. • Examine frequency domain modulator for 5. 5 and 11 Mbps CCK signaling. • Examine frequency domain modulator for 5. 5 and 11 Mbps PBCC signaling. • Compare 802. 11 b frequency domain modulators to OFDM modulator. • Cyclic extensions for Barker or CCK transmissions (non 802. 11 b variant). Submission 2 Mark Webster, Intersil

July 2000 doc. : IEEE 802. 11 -00/202 1 and 2 Mbps BARKER Mode: Time Domain Modulator 1 Mbps: BPSK 2 Mbps: QPSK Time Domain Multiply time Wide Sinc Spectrum Narrow Sinc Spectrum Submission 3 Mark Webster, Intersil

July 2000 doc. : IEEE 802. 11 -00/202 Barker Code Viewed in Discrete Domain DFT SPECTRUM 11 Chip BARKER Code +1 -1 Submission 4 Mark Webster, Intersil

July 2000 doc. : IEEE 802. 11 -00/202 Pulse Shape Envelop Barker Code Spreading Detail Chip Pulse +1 time -1 Periodically Extended Barker Samples Submission convolution 5 Periodically Extended Barker Chips Mark Webster, Intersil

July 2000 doc. : IEEE 802. 11 -00/202 Barker Mode Signaling Revisited 1 Mbps: BPSK 2 Mbps: QPSK Time Domain Multiply Equals Frequency Domain Convolution time Submission 6 Composite Mark Webster, Intersil

July 2000 doc. : IEEE 802. 11 -00/202 Spread Spectrum: Stacked Carriers Composite Constituent Stacked Carriers Submission Pulse Shape Envelop 7 Mark Webster, Intersil

July 2000 doc. : IEEE 802. 11 -00/202 Sub-Carrier Amplitude/Phase freq. MHz amp. Freq. Resp phz. Freq. Resp. Deg -5 1. 0000 40. 4941 -4 1. 0000 -24. 9605 -3 1. 0000 -90. 4150 -2 1. 0000 57. 6877 -1 1. 0000 138. 6759 0 0. 2887 0 1 1. 0000 -138. 6759 2 1. 0000 -57. 6877 3 1. 0000 90. 4150 4 1. 0000 24. 9605 5 1. 0000 -40. 4941 Submission 8 Mark Webster, Intersil

July 2000 doc. : IEEE 802. 11 -00/202 1 and 2 Mbps BARKER Mode: Frequency Domain Modulator Info Bit(s) BPSK/QPSK Rotation 1 Constellation Mapper Compute Amp/Phz of each Subcarrier 11 11 11 pt. IFFT P/S A 8 ejq 8 A 10 ejq 10 A 1 ejq 1 A 3 ejq 3 A 5 ejq 5 A 2 ejq 2 A 4 ejq 4 A 7 ejq 7 A 9 ejq 9 A 11 ejq 11 Barker Spectrum A 6 ejq 6 -5 Submission 9 -4 -3 -2 -1 0 1 Freq (MHz) 2 3 4 5 Mark Webster, Intersil

July 2000 Submission 2 Mbps Subcarrier Constellations 10 doc. : IEEE 802. 11 -00/202 Mark Webster, Intersil

July 2000 doc. : IEEE 802. 11 -00/202 5. 5 Mbps CCK Mode: Time Domain Modulator QPSK Time Domain Multiply time 4 Spreading Codes time Submission 11 Mark Webster, Intersil

July 2000 doc. : IEEE 802. 11 -00/202 5. 5 Mbps CCK Mode: Frequency Domain Modulator 2 Info Bits QPSK Rotation Constellation Mapper 2 Info Bits 1 Compute Amp/Phz of each Subcarrier 8 4 Codeword Spectrums 8 8 pt. IFFT A 1 ejq 1 A 3 ejq 3 A 5 ejq 5 A 7 ejq 7 A 2 ejq 2 A 4 ejq 4 A 6 ejq 6 A 8 ejq 8 1 Submission 12 P/S 2 3 4 5 6 7 8 Mark Webster, Intersil

July 2000 Submission 5. 5 Mbps Codeword Subcarrier Spectrumsdoc. : IEEE 802. 11 -00/202 13 Mark Webster, Intersil

July 2000 5. 5 Mbps Subcarrier Constellations doc. : IEEE 802. 11 -00/202 QAM Constellations Submission 14 Mark Webster, Intersil

July 2000 doc. : IEEE 802. 11 -00/202 11 Mbps CCK Mode: Time Domain Modulator QPSK Time Domain Multiply time 64 Spreading Codes time Submission 15 Mark Webster, Intersil

July 2000 doc. : IEEE 802. 11 -00/202 11 Mbps CCK Mode: Frequency Domain Modulator 2 Info Bits QPSK Rotation Constellation Mapper 6 Info Bits 1 Compute Amp/Phz of each Subcarrier 8 64 Codeword Spectrums 8 8 pt. IFFT A 1 ejq 1 A 3 ejq 3 A 5 ejq 5 A 7 ejq 7 A 2 ejq 2 A 4 ejq 4 A 6 ejq 6 A 8 ejq 8 1 Submission 16 P/S 2 3 4 5 6 7 8 Mark Webster, Intersil

July 2000 11 Mbps Subcarrier Constellations doc. : IEEE 802. 11 -00/202 QAM Constellations Sub-Carriers 1, 3, 5, 7 Submission Sub-Carriers 2, 4, 6, 8 17 Mark Webster, Intersil

July 2000 doc. : IEEE 802. 11 -00/202 11 Mbps PBCC Mode: Frequency Domain Modulator 8 Info Bits Compute Amp/Phz of each Subcarrier 8 8 pt. IFFT P/S A 1 ejq 1 A 3 ejq 3 A 5 ejq 5 A 7 ejq 7 A 2 ejq 2 A 4 ejq 4 A 6 ejq 6 A 8 ejq 8 Constellation Mapper Exists, but is Complicated 1 Submission 18 2 3 4 5 6 7 8 Mark Webster, Intersil

July 2000 doc. : IEEE 802. 11 -00/202 OFDM DIRECTLY EMBRACES FREQUENCY DOMAIN SIGNALING Used to Eliminate the Need for IBI Equalizer 802. 11 A OFDM MODULATOR BLOCK DIAGRAM Scrambler Viterbi Encoder Interleaver Constellation Mapper Add Cyclic Extension Data Sub-Carrier Constellations BPSK Pilot Subcarriers Submission IFFT BPSK: 6, 9 Mbps QPSK: 12, 18 Mbps 16 QAM: 24, 36 Mbps 64 QAM: 48, 54 Mbps 19 Cyclically Extends Sub-Carriers Mark Webster, Intersil

July 2000 doc. : IEEE 802. 11 -00/202 802. 11 a OFDM Symbol Equivalent to 64 Chip Codewords 20 MHz x 4 usecs = 80 samples 4 usecs OFDM Symbol Cyclic Extend 16 Samples IFFT/FFT SPAN 64 Samples time ~16. 25 MHz 312. 5 KHz Tone Spacing 52 Subcarriers . . . frequency Submission 20 Mark Webster, Intersil

July 2000 doc. : IEEE 802. 11 -00/202 Cyclic Extensions Can Be Used on Any Codeword 1 2 3 4 5 6 7 8 9 10 11 Original Codeword Smoothly Extends Sub-Carriers in Time 10 11 1 2 3 4 5 6 7 8 9 10 11 Cyclically. Extended Codeword Submission 21 Mark Webster, Intersil