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TGad Common Preamble May 2010 Date: Month Year

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1 TGad Common Preamble May 2010 Date: 2010-05-17 Month Year
doc.: IEEE /xxxxr0 May 2010 TGad Common Preamble Date: Author(s)/Supporter(s): Name Company Address Phone Abu-Surra, Shadi Samsung Ban, Koichiro Toshiba Banerjea, Raja Marvell Basson, Gal Wilocity Blanksby, Andrew Broadcom Borges, Daniel Apple Borison, David Ralink Cariou, Laurent Orange Chamberlin, Philippe Technicolor R&I Chang, Kapseok ETRI Chin, Francois I2R Christin, Philippe Chu, Liwen STMicroelectronics Chung, Hyun Kyu Coffey, Sean Realtek Cordeiro, Carlos Intel Derham, Thomas Dorsey, John Elboim, Yaron Fischer, Matthew Slide 1 Hongyuan Zhang, Marvell, et. al. Page 1 VInko Erceg, Broadcom

2 Jayabal, Raymond Jararaj s/o
Month Year doc.: IEEE /xxxxr0 May 2010 Author(s)/Supporter(s): Name Company Address Phone Giraud, Claude NXP Glibbery, Ron Peraso Technologies Golan, Ziv Wilocity Gong, Michelle Intel Grandhi, Sudheer InterDigital Grieve, David Agilent Grodzinsky, Mark Hansen, Christopher Broadcom Hart, Brian Cisco Hassan, Amer Microsoft Hong, Seung Eun ETRI Hosoya, Kenichi NEC Hosur, Srinath Texas Instruments Hsu, Alvin MediaTek Hsu, Julan Samsung Hung, Kun-Chien Jain, Avinash Qualcomm Jauh, Alan Jayabal, Raymond Jararaj s/o I2R Jeon, Paul LGE Jin, Sunggeun Jones, VK Joseph, Stacy Beam Networks Jun, Haeyoung Kaaja, Harald Nokia Kafle, Padam Kakani, Naveen Kasher, Assaf Kasslin, Mika Slide 2 Hongyuan Zhang, Marvell, et. al. Page 2 VInko Erceg, Broadcom

3 Nandagopalan, Saishankar
Month Year doc.: IEEE /xxxxr0 May 2010 Author(s)/Supporter(s): Name Company Address Phone Kim, Hodong Samsung Kim, Yongsun ETRI Kreifeldt, Rick Harman International Kwon, Edwin Kwon, Hyoungjin Kwon, Hyukchoon Laine, Tuomas Nokia Lakkis, Ismail Tensorcom Lee, Hoosung Lee, Keith AMD Lee, Wooyong Liu, Yong Marvell Lou, Hui-Ling Lynch, Brad Peraso Technologies Majkowski, Jakub Marin, Janne Maruhashi, Kenichi NEC Matsumoto, Taisuke Panasonic Meerson, Yury Wilocity Mese, Murat Broadcom Montag, Bruce Dell Myles, Andrew Cisco Nandagopalan, Saishankar Ngo, Chiu Nikula, Eero Park, DS Park, Minyoung Intel Peng, Xiaoming I2R Pi, Zhouyue Slide 3 Hongyuan Zhang, Marvell, et. al. Page 3 VInko Erceg, Broadcom

4 May 2010 Month Year doc.: IEEE 802.11-07/xxxxr0
Author(s)/Supporter(s): Name Company Address Phone Ponnampalam, Vish MediaTek Prasad, Narayan NEC Prat, Gideon Intel Qu, Xuhong I2R Ramachandran, Kishore Raymond, Yu Zhan Panasonic Roblot, Sandrine Orange Ronkin, Roee Wilocity Rozen, Ohad Sachdev, Devang NVIDIA Sadri, Ali Sampath, Hemanth Qualcomm Sanderovich, Amichai Sankaran, Sundar Atheros Scarpa, Vincenzo STMicroelectronics Seok, Yongho LGE Shao, Huai-Rong Samsung Shen, Ba-Zhong Broadcom Sim, Michael Singh, Harkirat Soffer, Menashe Song, Seungho SK Telecom Sorin, Simha Smith, Matt Stacey, Robert Subramanian, Ananth Sutskover, Ilan Slide 4 Hongyuan Zhang, Marvell, et. al. Page 4 VInko Erceg, Broadcom

5 May 2010 Month Year doc.: IEEE 802.11-07/xxxxr0
Author(s)/Supporter(s): Name Company Address Phone Taghavi, Hossain Qualcomm Takahashi, Kazuaki Panasonic Trachewsky, Jason Self Trainin, Solomon Intel Usuki, Naoshi Varshney, Prabodh Nokia Vertenten, Bart NXP Vlantis, George STMicroelectronics Wang, Chao-Chun MediaTek Wang, Homber TMC Wang, James Wong, David Tung Chong I2R Yee, James Yucek, Tevfik Atheros Yong, Su Khiong Marvell Zhang, Hongyuan Slide 5 Hongyuan Zhang, Marvell, et. al. Page 5 VInko Erceg, Broadcom

6 May 2010 Proposal overview This presentation is part and is in support of the complete proposal described in /432r0 (slides) and /433r0 (text) that: Supports data transmission rates up to 7 Gbps Supplements and extends the MAC and is backward compatible with the IEEE standard Enables both the low power and the high performance devices, guaranteeing interoperability and communication at gigabit rates Supports beamforming, enabling robust communication at distances beyond 10 meters Supports GCMP security and advanced power management Supports coexistence with other 60GHz systems Supports fast session transfer among 2.4GHz, 5GHz and 60GHz Hongyuan Zhang, Marvell, et. al.

7 Overview 1: SC and OFDM May 2010 Single Carrier (SC) vs. OFDM
In favor of OFDM Robustness in higher delay spread environments. Scalability—higher achievable throughput. In favor of single carrier Low PAPR, efficient PA, lower power consumption (at low delay spread) Lower complexity. Dual-Mode PHY would be the best solution for TGad: SC mainly targeted on low power applications with lower achievable throughput. OFDM mainly targeted on high throughput applications. SC and OFDM rates are defined in different MCSs in the same MCS table (starting from MCS1). A low rate common mode is necessary for any device to build up the beamformed links before transmitting regular higher rate SC/OFDM MCSs (refer to [3]). Named as “Control MCS”, which is MCS0 (see next slide) SC and OFDM modulation details refer to [1][2]. Slide 7 Hongyuan Zhang, Marvell, et. al.

8 May 2010 Overview 2: Control MCS Beamforming is necessary in 60GHz systems [3], and Control MCS (MCS 0) is required for SC/OFDM/Dual-Mode devices to communicate with each other before setting up beamforming connections. Main usage of Control MCS: Beacons Beamforming training. Control MCS Design Aspects: SNR sensitivity (or effective rate) targeted for ~15 dB lower than the sensitivity point of 1Gbps data rate (i.e. the beamforming gain). Use single carrier with much lower rate. Refer to [1]. Slide 8 Hongyuan Zhang, Marvell et. al.

9 Common Preamble Introduction
May 2010 Common Preamble Introduction Preamble is the beginning part of a PPDU—used for packet detection, AGC, frequency/timing synchronizations, channel estimation, and signaling of PSDU modulation (SC/OFDM/CtrlMCS). Regular SC and OFDM MCSs share a common preamble: Better support of the coexistence between various types of devices Each device (especially Dual-Mode device) need implement only one packet detection/synchronization/channel estimation mechanism. Appropriate auto-detection and re-sampling mechanism are required. Given that OFDM and SC Data portion uses different sampling rates. PPDU with Control MCS uses a longer preamble with similar design as SC/OFDM MCSs: Target on lower SNR sensitivity. Appropriate auto-detection between Control MCS and regular SC/OFDM preambles is needed. Slide 9 Hongyuan Zhang, Marvell, et. al.

10 I. Common Preamble for SC and OFDM
May 2010 I. Common Preamble for SC and OFDM PPDU and Common Preamble general frame formats: Preamble Header Payload SC or OFDM Mod Short Training Field (STF) Channel Estimation Field (CEF) Preamble is composed by STF and CEF: STF used for packet detection, AGC, frequency/timing synchronizations. CEF used for channel estimation and SC/OFDM mode auto-detection. Details see subsequent slides. Slide 10 Hongyuan Zhang, Marvell, et. al.

11 Preamble Composed by Golay Complementary Sequences
Ga128 Ga128 Ga128 Ga128 Ga128 -Ga128 GU512 GV512 GV128 STF, 15 periods (1920 chips) CEF, 1152 chips Preamble is composed by repeated 128-chip complimentary Golay sequences, denoted as Ga128/Gb128. GU512/GV512//GV128 are composed by Ga128/Gb128. Golay sequence is used due to its good auto-correlation property, and simple correlator structure. Composed by adders and shifters, no complex number multipliers required. Chip-level π/2-BPSK modulation achieve constant envelope with appropriate filter design. Slide 11 Hongyuan Zhang, Marvell, et. al.

12 STF Ga128 Ga128 Ga128 Ga128 Ga128 -Ga128 GU512 GV512 GV128 STF, 15 periods (1920 chips) CEF, 1152 chips Packet detection, AGC convergence, frequency synchronization and timing synchronization need to be conducted through STF. Appropriate symbol timing accuracy and frequency offset is required before entering channel estimations. 15 repetitions of Ga128 is a good tradeoff between PPDU efficiency and preamble detection/synchronization sensitivity. Preamble det/sync SNR sensitivity matches those for decoding Header, and Payload with MCS1. Slide 12 Hongyuan Zhang, Marvell, et. al.

13 CEF -Gb128 Gv128 GU512 GV512 -Gb128 Gv128 GU512 GV512 SC: Ga128 -Gb128
STF CEF Ga128 -Ga128 -Gb128 -Ga128 Gb128 -Ga128 -Gb128 Ga128 -Gb128 -Ga128 -Gb128 Gv128 Postfix of GV512 GU512 Prefix of GU512 GV512 Prefix of GV512 Postfix of GU512 OFDM: STF CEF Ga128 -Ga128 -Gb128 Ga128 -Gb128 -Ga128 -Gb128 Ga128 Gb128 Ga128 -Gb128 Gv128 Postfix of GV512 GU512 Prefix of GU512 GV512 Prefix of GV512 Postfix of GU512 Slide 13 Hongyuan Zhang, Marvell, et. al.

14 CEF—Discussions Zero side lobe of length 256 around the main tap.
Frame Delimiter can be realized by either detecting the sign flip at the end of STF, or detecting GU512 in CEF. GU512/GV512 are a pair of Golay complementary sequences, and are composed by Ga128/Gb128. GU512/GV512 are with 128-chip cyclic prefix and postfix in an overlapping format. Interference free time or frequency domain channel estimations can be realized. Zero side lobe of length 256 around the main tap. SC/OFDM Auto Detection. Required for Header/Data processing. Realized by swapping GU512/GV512 sequences in SC and OFDM PPDUs. Slide 14 Hongyuan Zhang, Marvell, et. al.

15 Preamble Sampling The preamble defined above is based on SC chip rate (1760MHz [1]). OFDM Header and Data are sampled with clock rate 2640MHz (3/2 of SC clock) [2]. Resampling of 3/2 is required for transmitting the common preamble in a OFDM modulated PPDU. 3x upsampling  go through a resampling filter hfilt  2x downsampling The TGad spec needs to define hfilt, so that receiver may recover the appropriate channel estimations. hfilt with a frequency response satisfying the OFDM transmit mask. Slide 15 Hongyuan Zhang, Marvell, et. al.

16 II. Preamble for Control MCS
May 2010 II. Preamble for Control MCS Gb128 Gb128 Gb128 Gb128 -Gb128 -Ga128 GU512 GV512 GV128 STF, 40 periods (5120 chips) CEF, 1152 chips Repeated Gb128 in STF (v.s. Ga128 in SC/OFDM preamble) for reliable auto-detection between Control MCS and regular SC/OFDM MCSs at low SNR. Control MCS needs to conduct a sync process different from regular SC/OFDM, for lower SNR target and longer delay channels. Longer STF for lower SNR sensitivity target and longer delay channels. 40 periods is a good tradeoff between efficiency and preamble detection/synchronization sensitivity. The preamble detection/sync SNR sensitivity matches that for decoding CP Header and Payload. CEF with the same format as in regular SC PPDU. Slide 16 Hongyuan Zhang, Marvell, et. al.

17 III. Golay Complementary Sequences (GCS)
Length-128 GCS and length-512 GCS are chosen for STF and CEF respectively, for the best tradeoff among efficiency, correlation complexity, signal acquisition sensitivity (especially for low rate packets), and channel estimation quality (especially for high rate packets). Choosing the GCS: Prefer to choose Golay Code Ga128 with zero-DC after chip level π/2 rotation (i.e. the STF in regular SC/OFDM MCSs). Prefer to choose GCP Ga128/Gb128 with large zero correlation zone (e.g. 64 taps) around the main tap. Delay units Dn are chosen to minimize the memory size. The GCP : D7 = [ ], W7 = [ ]. Slide 17 Hongyuan Zhang, Marvell, et. al.

18 Shorter GCS Choices A Ga64 code is needed for the GI insertions in SC MCSs [1]; and a Ga32 code is needed for data spreading in the Control MCS [1]. Choosing the shorter GCS: Use a subset of the delay vector D (reuse correlator hardware), with different coefficient W vectors. To get Ga64, D6 = [ ], W6 = [ ]. To get Ga32, D5 = [ ], W5 = [ ]. Guarantees good correlation properties between preamble and shorter GCS codes in SC data portion. Slide 18 Hongyuan Zhang, Marvell, et. al.

19 STF Cross-Correlations (AWGN)
Regular SC/OFDM STF Xcorr with Ga128: Ctrl MCS STF Xcorr with Gb128: Hongyuan Zhang, Marvell, et. al.

20 CEF Cross-Correlations (SC@AWGN)
SC CEF Xcorr with Gu512: Example CE Output (256 taps) SC CEF Xcorr with Gv512: Hongyuan Zhang, Marvell, et. al.

21 Conclusions A Common preamble proposed for different PHY modes.
May 2010 Conclusions A Common preamble proposed for different PHY modes. SC and OFDM MCSs share the same preamble structure. Control MCS uses a longer preamble with similar STF and CEF structures. Complementary Golay spreading codes are applied in preamble to simplify receiver processing. Appropriate auto-detection among different modes are also proposed. Slide 21 Hongyuan Zhang, Marvell, et. al.

22 References [1] 11-10-0429-r0 “TGad SC PHY”
[2] r0 “TGad OFDM PHY” [3] r0 “TGad Beamforming” Slide 22 Hongyuan Zhang, Marvell, et. al.


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