September 2013 doc IEEE 802 11 131109 r

September 2013 doc. : IEEE 802. 11 -13/1109 r 1 Consideration of PHY design for 1. 08 GHz channel Date: 2013 -09 -17 Presenter: Submission Slide 1 Changming Zhang

September 2013 doc. : IEEE 802. 11 -13/1109 r 1 Author List Submission Slide 2 Changming Zhang

Sept 2013 doc. : IEEE 802. 11 -13/1109 r 1 Abstract • This document is to propose a PHY design to support low power 1. 08 GHz PHY • It considers the PHY design with distortion compensation for I/Q imbalance for high order modulation and PA nonlinearity Submission Slide 3 Xiaoming Peng

September 2013 doc. : IEEE 802. 11 -13/1109 r 1 Roadmap • Background • 1. 08 GHz modulation and coding schemes • Frame structure • IQ imbalance estimation and compensation • PA nonlinearity treatment • Conclusion Submission Slide 4 Changming Zhang

September 2013 doc. : IEEE 802. 11 -13/1109 r 1 Channelization Consideration for 802. 11 aj It is necessary to define 1. 08 GHz PHY Submission Slide 5 Changming Zhang

September 2013 doc. : IEEE 802. 11 -13/1109 r 1 Roadmap • Background • 1. 08 GHz modulation and coding schemes • Frame structure • IQ imbalance estimation and compensation • PA nonlinearity treatment • Conclusion Submission Slide 6 Changming Zhang

September 2013 doc. : IEEE 802. 11 -13/1109 r 1 CMCS • Ctrl PHY CMCS Index Modulation Code Rate (Spreading Factor if not = 1) Payload Rate， 11 ad (Mbps) Payload Rate， 1. 08 GHz (Mbps) 0 Pi/2 -DBPSK 1/2 (32, with pi/2 -rotation) 27. 5 13. 75 Submission Slide 7 Changming Zhang

September 2013 doc. : IEEE 802. 11 -13/1109 r 1 CMCS • OFDM PHY CMCS Index Modulation Code Rate (Spreading Factor if not = 1) Payload Rate， 11 ad (Mbps) Payload Rate， 1. 08 GHz (Mbps) 18 SQPSK 1/2 693 346. 5 19 SQPSK 5/8 866. 25 433. 125 20 QPSK 1/2 1386 693 21 QPSK 5/8 1732. 5 866. 25 22 QPSK 3/4 2079 1039. 5 23 16 QAM 1/2 2772 1386 24 16 QAM 5/8 3465 1732. 5 25 16 QAM 3/4 4158 2079 26 16 QAM 13/16 4504. 5 2252. 25 27 64 QAM 5/8 5197. 5 2598. 75 28 64 QAM 3/4 6237 3118. 5 29 64 QAM 13/16 6756. 75 3378. 375 Submission Slide 8 Changming Zhang

September 2013 • MR SC PHY doc. : IEEE 802. 11 -13/1109 r 1 CMCS Index Modulation Code Rate (Spreading Factor if not = 1) Payload Rate， 11 ad (Mbps) Payload Rate， 1. 08 GHz (Mbps) 1 pi/2 -BPSK 1/2 (2) 385 192. 5 2 pi/2 -BPSK 1/2 770 385 3 pi/2 -BPSK 5/8 962. 5 481. 25 4 pi/2 -BPSK 3/4 1155 577. 5 5 pi/2 -BPSK 13/16 1251. 25 625 6 pi/2 -QPSK 1/2 1540 770 7 pi/2 -QPSK 5/8 1925 962. 5 8 pi/2 -QPSK 3/4 2310 1155 9 pi/2 -QPSK 13/16 2502. 5 1251. 25 Submission Slide 9 Changming Zhang

September 2013 doc. : IEEE 802. 11 -13/1109 r 1 CMCS • HR SC PHY CMCS Index Modulation Code Rate (Spreading Factor if not = 1) Payload Rate， 11 ad (Mbps) Payload Rate， 1. 08 GHz (Mbps) 10 pi/2 -16 QAM 1/2 3080 1540 11 pi/2 -16 QAM 5/8 3850 1925 12 pi/2 -16 QAM 3/4 4620 2310 13 pi/2 -16 QAM 13/16 2502. 5 14 pi/2 -64 QAM 1/2 2310 15 pi/2 -64 QAM 5/8 2887. 5 16 pi/2 -64 QAM 3/4 3465 17 pi/2 -64 QAM 13/16 3753. 75 Submission Slide 10 Changming Zhang

September 2013 doc. : IEEE 802. 11 -13/1109 r 1 CMCS • Low power PHY CMCS Index Modulation Code Rate (Spreading Factor if not = 1) Payload Rate， 11 ad (Mbps) Payload Rate， 1. 08 GHz (Mbps) 30 pi/2 -BPSK 13/28 626 313 31 pi/2 -BPSK 13/21 834 417 32 pi/2 -BPSK 52/63 1112 656 33 pi/2 -QPSK 13/28 1251 625. 5 34 pi/2 -QPSK 13/21 1668 834 35 pi/2 -QPSK 52/63 2224 1112 36 pi/2 -QPSK 13/14 2503 1251. 5 Submission Slide 11 Changming Zhang

September 2013 doc. : IEEE 802. 11 -13/1109 r 1 Roadmap • Background • 1. 08 GHz modulation and coding schemes • Frame structure • IQ imbalance estimation and compensation • PA nonlinearity treatment • Conclusion Submission Slide 12 Changming Zhang

September 2013 doc. : IEEE 802. 11 -13/1109 r 1 Frame structure Ctrl PHY (The same as 11 ad) OFDM PHY Submission Slide 13 Changming Zhang

September 2013 doc. : IEEE 802. 11 -13/1109 r 1 Frame structure MR SC PHY (The same as 11 ad) HR SC PHY Submission Slide 14 Changming Zhang

September 2013 doc. : IEEE 802. 11 -13/1109 r 1 Frame structure Low power PHY (The same as 11 ad) Submission Slide 15 Changming Zhang

September 2013 doc. : IEEE 802. 11 -13/1109 r 1 Roadmap • Background • 1. 08 GHz modulation and coding schemes • Frame structure • IQ imbalance estimation and compensation • PA nonlinearity treatment • Conclusion Submission Slide 16 Changming Zhang

September 2013 doc. : IEEE 802. 11 -13/1109 r 1 SFS-IQ imbalance estimation • SFS (Single-Frequency Sequence) F The phase difference between adjacent symbols is fixed at π/2, but it does not mean SFS is single-frequency signal, it is also constructed by symbols with the same time duration as the preamble and payload. F The transmit MASK mainly depends on the time duration of symbols, so the MASK is maintained after SFS is added. F SFS is in front of the original STF, thus synchronization and channel estimation are not impacted by IQ imbalance. F The length of SFS is 512, but only 128 symbols is enough for IQ imbalance estimation, others are used for initial capture before IQ imbalance estimation. Received baseband signal model: Submission Slide 17 Changming Zhang

September 2013 doc. : IEEE 802. 11 -13/1109 r 1 SFS-IQ imbalance estimation By calculating the second-order expectations of every two adjacent: symbols: Furthermore, let Then Thus, we can obtain: ü The reason for “≈’’ is due to the neglect of Δθ, which is reasonable as Δθ is quite small. Submission Slide 18 Changming Zhang

September 2013 doc. : IEEE 802. 11 -13/1109 r 1 SFS-IQ imbalance compensation With IQ imbalance, the received baseband signal can be expressed as: Without the presence of IQ imbalance, the baseband signals can be expressed as IQ compensation can be performed as: Submission Slide 19 Changming Zhang

September 2013 doc. : IEEE 802. 11 -13/1109 r 1 Explanations F The proposed method for IQ imbalance treatment is almost independent of CFO. F As IQ imbalance is compensated at the front of synchronization, then CFO estimation and compensation is not impacted by IQ imbalance. However, before IQ compensation, CFO estimation and compensation is quite hard. F Consider the complexity, we only address RX frequency-independent IQ imbalance. However, as for frequency-dependent IQ imbalance, the proposed method can also achieve some effects, even though the compensation is not perfect in this case. F Due to the limit of transmit EVM, TX IQ imbalance is not so significant as RX IQ imbalance, so the proposed method that only considers RX IQ imbalance is reasonable. Submission Slide 20 Changming Zhang

September 2013 doc. : IEEE 802. 11 -13/1109 r 1 F F Submission Slide 21 L=128, r=0. 05，∆ r=5 ； t=0. 005，∆ t=0. 5 Changming Zhang

September 2013 doc. : IEEE 802. 11 -13/1109 r 1 F F Submission Slide 22 L=128, r=0. 05，∆ r=5 ； t=0. 005，∆ t=0. 5 Changming Zhang

September 2013 doc. : IEEE 802. 11 -13/1109 r 1 F F Submission Slide 23 L=128, r=0. 05，∆ r=5 ； t=0. 005，∆ t=0. 5 Changming Zhang

September 2013 doc. : IEEE 802. 11 -13/1109 r 1 F F Submission Slide 24 L=128, r=0. 05，∆ r=5 ； t=0. 005，∆ t=0. 5 Changming Zhang

September 2013 doc. : IEEE 802. 11 -13/1109 r 1 Roadmap • Background • 1. 08 GHz modulation and coding schemes • Frame structure • IQ imbalance estimation and compensation • PA nonlinearity treatment • Conclusion Submission Slide 25 Changming Zhang

September 2013 doc. : IEEE 802. 11 -13/1109 r 1 Constellation diagram Standard constellation Distorted constellation PA nonlinearity distorts the constellation. We estimate the distorted constellation (DC) with TBLK in the Header for QAM signals, and demodulate signal according to DC. l Submission Slide 26 Changming Zhang

September 2013 doc. : IEEE 802. 11 -13/1109 r 1 DC estimation analysis Submission Slide 27 Changming Zhang

September 2013 doc. : IEEE 802. 11 -13/1109 r 1 Frame design l. TBLK and payload BLK are with the same modulation; l. Every constellation point appears with the same probability in the TBLK. Submission Slide 28 Changming Zhang

September 2013 doc. : IEEE 802. 11 -13/1109 r 1 DC estimation Ø Parameters to be estimated: T distorted amplitudes Ø Likelihood function (LF) for the k-th symbol: Ø Joint LF: Ø Let Ø By equaling the above first-order derivatives to zero, we can obtain the estimation results: , T additional phases: . (T＝ 3 for 16 QAM) , then Submission Slide 29 Changming Zhang

September 2013 doc. : IEEE 802. 11 -13/1109 r 1 DC demodulation p Hard decision demodulation: For every received symbol, the demodulation output is the DC point with the least distance to it. p Soft decision demodulation: The DC soft demodulation style is similar to the SC soft demodulation, where the SC points should be replaced by the DC points. For example, if we require the LLR output demodulation, it can be depicted as: Submission Slide 30 Changming Zhang

September 2013 doc. : IEEE 802. 11 -13/1109 r 1 F F Submission Slide 31 11 ad’s PA model OBO=6 d. B Changming Zhang

September 2013 doc. : IEEE 802. 11 -13/1109 r 1 F F Submission Slide 32 11 ad’s PA model OBO=6 d. B Changming Zhang

September 2013 doc. : IEEE 802. 11 -13/1109 r 1 F F Submission Slide 33 11 ad’s PA model OBO=6 d. B Changming Zhang

September 2013 doc. : IEEE 802. 11 -13/1109 r 1 F F Submission Slide 34 11 ad’s PA model OBO=6 d. B Changming Zhang

September 2013 doc. : IEEE 802. 11 -13/1109 r 1 Code Rate 1/2 5/8 3/4 13/16 Submission Slide 35 EVM (d. B) -19 -20 -21 -23 Changming Zhang

September 2013 doc. : IEEE 802. 11 -13/1109 r 1 Code Rate 1/2 5/8 3/4 13/16 Submission Slide 36 EVM (d. B) -19 -20 -21 -23 Changming Zhang

September 2013 doc. : IEEE 802. 11 -13/1109 r 1 Code Rate 1/2 5/8 3/4 13/16 Submission Slide 37 EVM(d. B) -24 -25 -26 -28 Changming Zhang

September 2013 doc. : IEEE 802. 11 -13/1109 r 1 Code Rate 1/2 5/8 3/4 13/16 Submission Slide 38 EVM(d. B) -24 -25 -26 -28 Changming Zhang

September 2013 doc. : IEEE 802. 11 -13/1109 r 1 Explanations F The preamble, CES and original Header are BPSK signals, and the impact of PA nonlinearity is neglectable. F Distorted constellation estimation is performed after equalization, thus the proposed method is decoupled of ISI. F If the transmit EVM is not controlled well, the impact of PA nonlinearity is serious especially for 64 -QAM, and the proposed method can overcome the impact well at receiver. F If the transmit EVM meets the requirements, PA nonlinearity is relatively weak, and impact is weaker, but the proposed method still achieves some performance improvement. Submission Slide 39 Changming Zhang

September 2013 doc. : IEEE 802. 11 -13/1109 r 1 F F r=0. 05，∆ r=5 ； t=0. 005，∆ t=0. 5 Code Rate 1/2 5/8 3/4 13/16 Submission Slide 40 EVM(d. B) -19 -20 -21 -23 Changming Zhang

September 2013 doc. : IEEE 802. 11 -13/1109 r 1 F F r=0. 05，∆ r=5 ； t=0. 005，∆ t=0. 5 Code Rate 1/2 5/8 3/4 13/16 Submission Slide 41 EVM(d. B) -19 -20 -21 -23 Changming Zhang

September 2013 doc. : IEEE 802. 11 -13/1109 r 1 F F r=0. 05，∆ r=5 ； t=0. 005，∆ t=0. 5 Code Rate 1/2 5/8 3/4 13/16 Submission Slide 42 EVM(d. B) -24 -25 -26 -28 Changming Zhang

September 2013 doc. : IEEE 802. 11 -13/1109 r 1 F F r=0. 05，∆ r=5 ； t=0. 005，∆ t=0. 5 Code Rate 1/2 5/8 3/4 13/16 Submission Slide 43 EVM(d. B) -24 -25 -26 -28 Changming Zhang

September 2013 doc. : IEEE 802. 11 -13/1109 r 1 Roadmap • Background • 1. 08 GHz modulation and coding schemes • Frame structure • IQ imbalance estimation and compensation • PA nonlinearity treatment • Conclusion Submission Slide 44 Changming Zhang

September 2013 doc. : IEEE 802. 11 -13/1109 r 1 Conclusion • CMCSs of 1. 08 GHz PHY ü For Ctrl PHY, OFDM PHY, and Low power PHY, the CMCSs are the same as that of 11 ad. ü SC PHY is divided into MR SC PHY and HR SC PHY, MR SC PHY corresponds to PSK modulation, and HR SC PHY corresponds to QAM modulation. Here 13/16 -16 QAM, and 64 QAM are new compared with 11 ad. • Frame structure of 1. 08 GHz PHY ü Including Ctrl PHY, OFDM PHY, MR SC PHY, HR SC PHY, and Low power PHY. ü The frame structure of Ctrl PHY, MR SC PHY, and Low power PHY are consistent with that of Ctrl PHY, SC PHY, and Low power PHY of IEEE 802. 11 ad, respectively. ü Compared with 11 ad, SFS is added at the beginning for OFDM PHY, which is used to estimate and compensate IQ imbalance. ü Compared with the SC PHY of 11 ad, also SFS is added at the beginning for HR SC PHY that used to estimate and compensate IQ imbalance. In addition, TBLK is added before payloads, which is used to estimate distorted constellation to react PA nonlinearity. • The proposed methods that compensate IQ imbalance and PA nonlinearity work well, which can be observed from the performance evaluation. Submission Slide 45 Changming Zhang

September 2013 doc. : IEEE 802. 11 -13/1109 r 1 Thanks！ Submission Slide 46 Changming Zhang