ETRI Proposal to IEEE 802.11 TGn August 2004 ETRI Proposal to IEEE 802.11 TGn Heejung Yu, Taehyun Jeon, Sok-Kyu Lee, Myung-Soon Kim, Eun-young Choi, Seung-Ku Hwang Next Generation Wireless LAN Research Team ETRI {heejung, thjeon, sk-lee, mskim75, eychoi, skhwang}@etri.re.kr Heejung Yu, ETRI
Contents Proposed technologies for >200Mbps in PHY Detail Standard August 2004 Contents Proposed technologies for >200Mbps in PHY MIMO-OFDM Dual band Detail Standard Simulation Results Conclusions Heejung Yu, ETRI
Proposed technologies August 2004 Proposed technologies for >200Mbps in PHY Heejung Yu, ETRI
Candidate technologies August 2004 Candidate technologies Legacy IEEE 802.11a => 20MHz BW, 54Mbps To achieve more than 100Mbps at the top of the MAC SAP, we need x3 or x4 data rate. Depending on MAC efficiency To extend x4 transmission MIMO (improve spectral efficiency) Bandwidth extension High order modulation High rate coding Heejung Yu, ETRI
MIMO Data rate can be increased with the number of Tx antennas. August 2004 MIMO Data rate can be increased with the number of Tx antennas. We have some problem in using 3 and more stream. Implementation complexity Limitation on antenna spacing, high MIMO channel correlation can be a problem. So, we cannot fully rely on the MIMO technology for 3 or 4x data rate. Heejung Yu, ETRI
Bandwidth Extension Clock doubling Dual band New OFDM parameter August 2004 Bandwidth Extension Clock doubling Dual band New OFDM parameter 64 subcarrier 40MHz 64 subcarrier 64 subcarrier 40MHz 20MHz xxx subcarrier 40MHz Heejung Yu, ETRI
Bandwidth Extension Clock doubling Dual band New OFDM parameter August 2004 Bandwidth Extension Clock doubling 802.11a modem with clock switching function Protection mechanism for compatibility Dual band 802.11a modem (2 units) or 802.11a modem with some change( using 128 point FFT) Compatible with legacy 802.11a (refer specification part) New OFDM parameter 802.11a + new modem with new OFDM parameters( # of subcarrier, # of CP, etc.) Heejung Yu, ETRI
Dual-band Merits Demerits More flexible implementation August 2004 Dual-band Merits More flexible implementation We extend threefold, fourfold BW systematically by increasing number of FFT or FFT size. Compatible preamble and SIGNAL field is possible. More robust to DC-offset (11 DC-carrier) Demerits Reduce the number of channel In some countries, only 20MHz channel usage is allowed Heejung Yu, ETRI
Max. data rate (mandatory) August 2004 Max. data rate (mandatory) # of Tx and Rx antennas = 3 We use 2 Tx antennas out of 3 antennas (include Tx antenna selection option) # of Tx streams (MIMO gain) = 2 Dual-band (data rate gain) = 2 Achievable Data Rate = 2 x 2 x (legacy rate) = 216Mbps In optional mode, 288Mbps (256-QAM, 3/4 code rate) is possible. Heejung Yu, ETRI
Details of ETRI PHY specification August 2004 Details of ETRI PHY specification Heejung Yu, ETRI
Main features Compatible with IEEE 802.11a Bandwidth : 20 or 40MHz August 2004 Main features Compatible with IEEE 802.11a Bandwidth : 20 or 40MHz Multiple antennas : 2 Tx antennas 3 Rx antennas are recommended. Tx antenna selection is available. Modulation : Legacy OFDM, SDM-OFDM, STBC-OFDM Data Rate 20MHz BW:6,9,12,18,24,36,48,54,72,96,108,128,144 Mbps 40MHz BW : doubled Heejung Yu, ETRI
TXVECTOR, RXVECTOR BANDWIDTH and MODE are added in TX/RX VECTOR August 2004 TXVECTOR, RXVECTOR BANDWIDTH and MODE are added in TX/RX VECTOR BANDWIDTH : PHY can use consecutive two 20MHz band for higher data rate. MODE : transmission scheme Legacy OFDM SDM-OFDM (Spatial Division Multiplexing) STBC-OFDM (Space-Time Block Code) Heejung Yu, ETRI
Frame Format Legacy OFDM STBC-OFDM, SDM-OFDM August 2004 Heejung Yu, ETRI
PCLP Preambles Legacy OFDM STBC-OFDM, SDM-OFDM Even Even Even Odd Odd August 2004 PCLP Preambles Legacy OFDM STBC-OFDM, SDM-OFDM Even Even Even Odd Odd Odd Odd Even Heejung Yu, ETRI
Preamble Pattern (Single Antenna Single Band) August 2004 Preamble Pattern (Single Antenna Single Band) Short preamble Long preamble Heejung Yu, ETRI
Preamble Pattern (Dual Antenna Single Band) August 2004 Preamble Pattern (Dual Antenna Single Band) Short preamble (Ant 0 : even subcarriers, Ant 1 : odd subcarriers) Ant 0 Ant 1 Long preamble Heejung Yu, ETRI
Preamble Pattern (Single Antenna Dual Band) August 2004 Preamble Pattern (Single Antenna Dual Band) Short preamble (concatenation of single band preambles) Long preamble (concatenation of single band preambles) Heejung Yu, ETRI
Preamble Pattern (Dual Antenna Dual Band) August 2004 Preamble Pattern (Dual Antenna Dual Band) Short preamble (concatenation of single band preambles) Ant 0 Ant 1 Long preamble (concatenation of single band preambles) Heejung Yu, ETRI
Preamble Properties Repetition property is maintained August 2004 Preamble Properties Repetition property is maintained Same auto-correlation property PAPR for single band preamble Legacy-OFDM mode : 2.09dB (short), 3.17dB(long) SDM/STBC-OFDM mode Antenna 0 : 4.69dB(short), 5.58dB(long) Antenna 1 : 4.69dB(short), 5.85dB(long) PAPR for dual band preamble Legacy-OFDM mode : 5.10dB (short), 6.18dB(long) Antenna 0 : 5.80dB(short), 7.05dB(long) Antenna 1 : 5.80dB(short), 8.86dB(long) Cross correlation between Tx antenna Orthogonal preamble by using subcarriers alternatively Heejung Yu, ETRI
August 2004 SIGNAL bit assignment 802.11n device uses the R4 to distinguish the legacy and multi-antenna R4 = 1 : legacy OFDM R4 = 0 : multi-antenna (STBC-OFDM, SDM-OFDM) 802.11n device uses the reserved bit to distinguish STBC-OFDM and SDM-OFDM. For legacy device, discard For Alamouti code, A = 0 For SDM, A = 1 Heejung Yu, ETRI
RATE and ANTENNA field definition Rate-dependant parameters August 2004 RATE and ANTENNA field definition Rate-dependant parameters {R1-R4, A} Data rate Modulation Coding rate NBPSC NCBPS NDBPS Antenna mode 1101x 6 BPSK 12 1 48 24 Legacy OFDM 1111x 9 34 36 0101x 12 QPSK 2 96 0111x 18 72 1001x 16-QAM 4 192 1011x 144 0001x 64-QAM 2/3 288 0011x 54 216 Heejung Yu, ETRI
RATE and ANTENNA field definition Rate-dependant parameters August 2004 RATE and ANTENNA field definition Rate-dependant parameters {R1-R4, A} Data rate Modulation Coding rate NBPSC NCBPS NDBPS Antenna mode 11000 6 BPSK 12 1 48 24 STBC-OFDM 11100 9 34 36 01000 12 QPSK 2 96 01100 18 72 10000 16-QAM 4 192 10100 144 00000 64-QAM 2/3 288 00100 54 216 Heejung Yu, ETRI
RATE and ANTENNA field definition Rate-dependant parameters August 2004 RATE and ANTENNA field definition Rate-dependant parameters {R1-R4, A} Data rate Modulation Coding rate NBPSC NCBPS NDBPS Antenna mode 10101 72 16-QAM 34 8 384 288 SDM-OFDM 00001 96 64-QAM 2/3 12 576 00101 108 432 11001 128 256-QAM 16 768 512 01001 144 These parameters are based on single band. NBPSC : Coded bits per subcarrier NCBPS : Coded bits per OFDM symbol NDBPS : Data bits per OFDM symbol Heejung Yu, ETRI
SIGNAL Field Modulation August 2004 SIGNAL Field Modulation Single Antenna single band (same as 802.11a) Subcarrier allocation : Dual antenna single band Single antenna dual band Dual antenna dual band Heejung Yu, ETRI
DATA Field (changed parts) Pad bits, Data arbitrator August 2004 DATA Field (changed parts) Pad bits, Data arbitrator Pad bits To make DATA bits to be an integer multiple of NDBPS (Legacy OFDM, SDM-OFDM), or 2NDBPS(STBC-OFDM). Data arbitrator Receive one byte from MAC, even numbered 4 bits directed to scrambler(channel) 0 and odd numbered 4 bits to scrambler(channel) 1. Heejung Yu, ETRI
DATA Field (changed parts) Interleaving August 2004 DATA Field (changed parts) Interleaving Interleaver : block interleaver Interleaver size : NCBPS(single band), 2NCBPS(dual band) Interleaver (Single band. In dual band, all NCBPS’s are replaced with 2NCBPS) Deinterleaver (Single band. In dual band, all NCBPS’s are replaced with 2NCBPS) Heejung Yu, ETRI
DATA Field (changed parts) Modulation mapping August 2004 DATA Field (changed parts) Modulation mapping Optional 256-QAM is added to 802.11a modulations Kmod = Heejung Yu, ETRI
DATA Field (changed parts) Antenna arbitration August 2004 DATA Field (changed parts) Antenna arbitration Legacy OFDM Single band case Dual band case Heejung Yu, ETRI
DATA Field (changed parts) Antenna arbitration August 2004 DATA Field (changed parts) Antenna arbitration STBC-OFDM Single band case Ant 0 Ant 1 Dual band case Ant 0 Ant1 Heejung Yu, ETRI
DATA Field (changed parts) Antenna arbitration August 2004 DATA Field (changed parts) Antenna arbitration SDM-OFDM Single band case Ant 0 Dual band case Ant 1 Heejung Yu, ETRI
DATA Field (changed parts) OFDM Modulation August 2004 DATA Field (changed parts) OFDM Modulation OFDM modulation for i-th antenna j-th channel One OFDM symbol modulation Concatenation of multiple OFDM symbols OFDM modulation for dual band Heejung Yu, ETRI
Transmitter structure August 2004 Transmitter structure Using one 128 (I)FFT structure Heejung Yu, ETRI
Transmitter structure August 2004 Transmitter structure Modified structure with 64 point FFT Heejung Yu, ETRI
August 2004 Transmit spectrum Tx spectrum for dual band is the extended version of legacy 11a spectrum Heejung Yu, ETRI
August 2004 Simulation Results Heejung Yu, ETRI
August 2004 Detection Method In Legacy OFDM, Maximal Ratio Combining method is used. In SDM-OFDM, Zero Forcing scheme is used. The simplest and reasonable method considering both implementation complexity and performance In higher order modulation and smaller number of Nt case, SNR loss between ZF and ML (Maximum Likelihood) becomes lower. Heejung Yu, ETRI
AWGN performance 1 Tx, 1 Rx antenna (only for Legacy mode) August 2004 Heejung Yu, ETRI
August 2004 AWGN performance 2 Tx, 2 Rx antennas Heejung Yu, ETRI
August 2004 AWGN performance 2 (out of 3) Tx, 3 Rx antennas (We select 2 antennas out of 3 Tx antennas.) Heejung Yu, ETRI
August 2004 AWGN performance 2 (out of 4) Tx, 4 Rx antennas (We select 2 antennas out of 4 Tx antennas.) In AWGN channel, Nr => detection SNR (no diversity gain) => (Nr = 4) has 3dB gain over (Nr = 2). Nt , SNR per info. bit (to normalize total Tx power) => 54Mbps has 3dB gain over 108Mbps. Heejung Yu, ETRI
Non-AWGN performance 2 Tx and 3 Rx antennas are used. August 2004 Non-AWGN performance 2 Tx and 3 Rx antennas are used. In Legacy mode, randomly selected single Tx antenna is used. Antenna spacing Tx spacing : 1 wavelength (2 out of 3 antennas are used.) Rx spacing : ½ wavelength (3 antennas) Power amplifier backoff : 10dB (p=3 RAPP mode) CFO and timing offset : -13.675ppm Channel model : B, D (with fluorescent effect), and E (NLOS) Packet size : 1000 bytes Heejung Yu, ETRI
Non-AWGN performance Channel model B (NLOS) August 2004 Heejung Yu, ETRI
Non-AWGN performance Channel Model D (NLOS) August 2004 Heejung Yu, ETRI
Non-AWGN performance Channel model E (NLOS) August 2004 Heejung Yu, ETRI
Offset effect Channel E (NLOS) Solid : offset compensation performance August 2004 Offset effect Channel E (NLOS) Solid : offset compensation performance Dash : zero offset performance CFO and timing tracking loop coefficients are optimized for high data rates. Heejung Yu, ETRI
Offset effect Channel E (LOS), at 50dB SNR August 2004 Offset effect Channel E (LOS), at 50dB SNR Constellation of 108Mbps mode with different offset values 40ppm 20ppm -20ppm -40ppm Heejung Yu, ETRI
Offset effect Channel E (LOS), at 50dB SNR August 2004 Offset effect Channel E (LOS), at 50dB SNR Constellation of 6Mbps mode with different offset values 40ppm 10ppm -10ppm -40ppm Heejung Yu, ETRI
August 2004 Conclusions Heejung Yu, ETRI
August 2004 Conclusions In this proposal, MIMO-OFDM with 2 transmit antennas and dual band scheme are used for higher data rate (throughput). SDM-OFDM : double data rate Dual band : double data rate STBC-OFDM : increase link reliability (optional) To satisfy the FR (100Mbps throughput in 20MBz), 256-QAM is added (144Mbps in 20MHz band) Compatible with 802.11a (Preamble and SINGAL structure) Heejung Yu, ETRI
August 2004 Appendix Heejung Yu, ETRI
August 2004 A1. Dual-band Subcarriers of 128 points FFT are divided into two 64 subcarriers corresponding to 64 FFT in 802.11a/g. 64 subcarriers 40MHz 11 “0” carriers Heejung Yu, ETRI
A2. Preamble Pattern (Dual Antenna Single Band) August 2004 A2. Preamble Pattern (Dual Antenna Single Band) Short preamble (Ant 0 : even subcarriers, Ant 1 : odd subcarriers) Long preamble Heejung Yu, ETRI
A2. Preamble Pattern (Single Antenna Dual Band) August 2004 A2. Preamble Pattern (Single Antenna Dual Band) Short preamble (concatenation of single band preambles) Long preamble (concatenation of single band preambles) Heejung Yu, ETRI
A2. Preamble Pattern (Dual Antenna Dual Band) August 2004 A2. Preamble Pattern (Dual Antenna Dual Band) Short preamble (concatenation of single band preambles) Long preamble (concatenation of single band preambles) Heejung Yu, ETRI