January 2012 doc IEEE 802 11 111484 r

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January 2012 doc. : IEEE 802. 11 -11/1484 r 5 11 ah Data Transmission

January 2012 doc. : IEEE 802. 11 -11/1484 r 5 11 ah Data Transmission Flow Date: 2012 -01 -16 Authors: Submission Slide 1 Hongyuan Zhang, et. Al.

January 2012 doc. : IEEE 802. 11 -11/1484 r 5 Authors continued: Submission Slide

January 2012 doc. : IEEE 802. 11 -11/1484 r 5 Authors continued: Submission Slide 2 Hongyuan Zhang, et al

January 2012 doc. : IEEE 802. 11 -11/1484 r 5 Abstract This presentation proposes

January 2012 doc. : IEEE 802. 11 -11/1484 r 5 Abstract This presentation proposes the data transmission flows for 11 ah PPDUs, including 1 MHz, 2 MHz, and 4 / 8/ 16 MHz packets. Submission Slide 3 Hongyuan Zhang, et. Al.

January 2012 doc. : IEEE 802. 11 -11/1484 r 5 Overview • TGah decided

January 2012 doc. : IEEE 802. 11 -11/1484 r 5 Overview • TGah decided to have 2/4/8/16 MHz signals that are basically down clocked versions of 11 ac 20 / 40 / 80 / 160 MHz, also an 1 MHz signal based on 32 FFT was introduced. – Both 2 MHz and 1 MHz receptions are mandatory. • We propose the 11 ah data transmission flow in this presentation. – Flow for regular MCS. – Flow for a new MCS 0 - 2 x Repetition mode for range extension. Submission Slide 4 Hongyuan Zhang, et. Al.

January 2012 doc. : IEEE 802. 11 -11/1484 r 5 I. Transmission Flow for

January 2012 doc. : IEEE 802. 11 -11/1484 r 5 I. Transmission Flow for Regular MCSs • Apply the same Tx flow in 11 ac in the data tones for the data field. Submission Slide 5 Hongyuan Zhang, et. Al.

January 2012 doc. : IEEE 802. 11 -11/1484 r 5 Tone Plans • >=2

January 2012 doc. : IEEE 802. 11 -11/1484 r 5 Tone Plans • >=2 MHz follows the same tone plans as the corresponding FFT sizes in 11 ac. • Define the 1 MHz tone allocation as: 24 Data tones, 2 Pilot tones at tone indices +/-7, 3 Guard tones on left and 2 guard tones on right, and 1 DC tone. – 24 Data tones does not impose any MCS exclusion as seen in 11 ac, suitable for all MCSs. The next “good number” is 18 tones, but the spectrum waste would be too high. – 2 and 3 guard tones are not worse than 64 FFT (3/4 guard tones) regarding the filter designs. – 2 pilot tones seems sufficient for phase/frequency tracking (see Appendix). …. . -16 -15 -14 -13 …. . -2 -1 0 1 Data (pilot at -7) Submission Slide 6 2 13 14 15 Data (pilot at +7) Hongyuan Zhang, et. Al.

January 2012 doc. : IEEE 802. 11 -11/1484 r 5 Discussions • Each block

January 2012 doc. : IEEE 802. 11 -11/1484 r 5 Discussions • Each block is the same as or similar to the corresponding part of 11 ac. – The 11 ah stream parser is the same as 11 ac. – The 11 ah encoder parser and segment parser (16 MHz only) are the same as 11 ac; NES in the MCSs of 2/4/8/16 MHz is the same as the corresponding values in 11 ac; and NES = 1 in all the MCSs of 1 MHz. • Up to 4 space-time streams (refer to [3]). • The draft specification shall support following MCSs: – For 1 MHz, 11 ac MCS 0~9, as well as an MCS 0 -rep 2 mode. – For >=2 MHz, the MCS tables for BCC are the same as the corresponding tables in 11 ac before downclocking, i. e. same MCS exclusions for BCC as in 11 ac. • In 1 MHz, interleaver is applied for all MCSs incl. MCS 0 -Rep 2, Ncol=8, Nrot TBD. (refer to [4]) Submission Slide 7 Hongyuan Zhang, et. Al.

November 2011 doc. : IEEE 802. 11 -11/1484 r 5 II. MCS 0 Rep

November 2011 doc. : IEEE 802. 11 -11/1484 r 5 II. MCS 0 Rep 2 Mode in 1 MHz • An MCS 0 -Rep 2 mode in 1 MHz is needed to improve the range (refer to [1]). – Lead to the lowest data rate ~150 Kbps, reach the longest range – ~6 d. B gain compared with MCS 0 of 64 FFT mode. • Similar to the gap between 1 Mbps (DSSS) and 6 Mbps (11 g) in 2. 4 GHz. • We propose a simple 2 x repetition mode that imposes minimal Tx and Rx design change from regular MCSs. Submission Slide 8 Hongyuan Zhang, et. Al.

January 2012 doc. : IEEE 802. 11 -11/1484 r 5 MCS 0 Rep 2

January 2012 doc. : IEEE 802. 11 -11/1484 r 5 MCS 0 Rep 2 Tx Flow IDFT Interleaver BPSK mapper After repetition, NCBPS = 12 (same as 1 SS-MCS 0) bits per symbol Slide 9 Spatial Mapping 2 x Block-Wise Repetition FEC Scrambler Submission Ncol = 8 GI & Window Analog & RF : : IDFT Hongyuan Zhang, et. Al.

January 2012 doc. : IEEE 802. 11 -11/1484 r 5 Discussions • MCS 0

January 2012 doc. : IEEE 802. 11 -11/1484 r 5 Discussions • MCS 0 Rep 2 is applied only for single space-time stream. – NSS=1, no STBC • The “ 2 x block-wise repetition” performed on a per-OFDM symbol basis: – Cout=[C 1…. C 2 N , C 1…. C 2 N ], where [C 1…. C 2 N ] are the FEC output bits per symbol. DBPS • Interleaver parameters are the same as regular MCS 0. – Ncol = 8 • Receiver may conduct MRC combining to improve SNR. Submission Slide 10 Hongyuan Zhang, et. Al.

January 2012 doc. : IEEE 802. 11 -11/1484 r 5 Performance in AWGN, 2

January 2012 doc. : IEEE 802. 11 -11/1484 r 5 Performance in AWGN, 2 MHz Receiver Assumptions: • 4 LTF 1 repetitions in 1 MHz Preamble (refer to [1]) • 1 MHz with 24 data tones, Intlv Ncol=8 • SNR is time domain: avg received power over noise in 2 MHz Submission Slide 11 Hongyuan Zhang, et. Al.

November 2011 doc. : IEEE 802. 11 -11/1484 r 5 Performance in SCM-UMa, 2

November 2011 doc. : IEEE 802. 11 -11/1484 r 5 Performance in SCM-UMa, 2 MHz Receiver Submission Slide 12 Hongyuan Zhang, et. Al.

November 2011 doc. : IEEE 802. 11 -11/1484 r 5 III. Short GI Support

November 2011 doc. : IEEE 802. 11 -11/1484 r 5 III. Short GI Support • In [1][2] we propose a green field type of preamble for single user packets. • Note that in 11 n Green Field preamble, Short GI is not allowed if NSTS=1, due to the decoding delay for the HTSIG field. HT-STF HT-LTF 1 HT-SIG DATA 1 DATA 2 DATA 3 …. . Decoding delay • In 11 ah, most of the traffic will be SU 1 SS, not allowing Short GI loses about 10% of peak throughput. – • It is also easier to support SGI than in 11 n/ac, because even SGI (4 us) is much longer than a typical indoor channel multipath delay. Propose that in any 11 ah short GI packet, short GI starts from the 2 nd Data symbol, and the 1 st Data symbol is always long GI. – – Include Multi-stream or MU packets. For a unified receiver processing. STF LTF 1 SIG Indicates SGI Submission Slide 13 Data 1 (LGI) Data 2 (SGI) Data 3 (SGI) Data 4 …. . (SGI) Hongyuan Zhang, et. Al.

January 2012 doc. : IEEE 802. 11 -11/1484 r 5 Straw Poll – 1

January 2012 doc. : IEEE 802. 11 -11/1484 r 5 Straw Poll – 1 (from Nov meeting) • Do you support the general transmission flow for 11 ah regular MCSs as in slide 5? Submission Slide 14 Hongyuan Zhang, et. Al.

January 2012 doc. : IEEE 802. 11 -11/1484 r 5 Straw Poll – 2

January 2012 doc. : IEEE 802. 11 -11/1484 r 5 Straw Poll – 2 (new) • Do you support the 11 ah tone plans as specified in slide 6? Submission Slide 15 Hongyuan Zhang, et. Al.

January 2012 doc. : IEEE 802. 11 -11/1484 r 5 Straw Poll— 3 (new)

January 2012 doc. : IEEE 802. 11 -11/1484 r 5 Straw Poll— 3 (new) • Do you support the followings regarding parsers? – The 11 ah stream parser is the same as 11 ac. – The 11 ah encoder parser and segment parser (16 MHz only) are the same as 11 ac; NES in the MCSs of 2/4/8/16 MHz is the same as the corresponding values in 11 ac; and NES = 1 in all the MCSs of 1 MHz. Submission Slide 16 Hongyuan Zhang, et. Al.

January 2012 doc. : IEEE 802. 11 -11/1484 r 5 Straw Poll – 4

January 2012 doc. : IEEE 802. 11 -11/1484 r 5 Straw Poll – 4 (new) • Do you agree with the followings regarding 11 ah MCS table? – For 1 MHz, 11 ac MCS 0~9, as well as an MCS 0 -rep 2 mode. – For >=2 MHz, the MCS tables for BBC are the same as the corresponding tables in 11 ac before downclocking, i. e. same MCS exclusions for BCC as in 11 ac. Submission Slide 17 Hongyuan Zhang, et. Al.

January 2012 doc. : IEEE 802. 11 -11/1484 r 5 Straw Poll – 5

January 2012 doc. : IEEE 802. 11 -11/1484 r 5 Straw Poll – 5 (from Nov meeting) • Do you support the transmission flow for MCS 0 -Rep 2 mode as specified in slides 9~10? Submission Slide 18 Hongyuan Zhang, et. Al.

January 2012 doc. : IEEE 802. 11 -11/1484 r 5 Straw Poll – 6

January 2012 doc. : IEEE 802. 11 -11/1484 r 5 Straw Poll – 6 (from Nov meeting, with a small change) • Do you support that in any 11 ah short GI packet, short GI starts from the 2 nd Data symbol, and the 1 st Data symbol is always long GI? – Include Multi-stream or MU packets. Submission Slide 19 Hongyuan Zhang, et. Al.

January 2012 doc. : IEEE 802. 11 -11/1484 r 5 References [1] 11 -11

January 2012 doc. : IEEE 802. 11 -11/1484 r 5 References [1] 11 -11 -1482 -00 -00 ah-preamble-format-for-1 -MHz [2] 11 -11 -1483 -00 -00 ah-11 ah-preamble-for-2 MHz-and-beyond [3] 11 -11 -1275 -01 -00 ah-spatial-stream-support [4] 11 -12 -0113 -00 -00 ah-32 FFT-Interleaver Submission Slide 20 Hongyuan Zhang, et. Al.

January 2012 doc. : IEEE 802. 11 -11/1484 r 5 Appendix • Simulations to

January 2012 doc. : IEEE 802. 11 -11/1484 r 5 Appendix • Simulations to compare 2 pilots versus 4 pilots. – Assume 40 ppm CFO, 1 x 1, DNLOS or AWGN, MCS 7, pilots are used to track phase and correct CFO. – First set of simulations is to compare the gap of CFO on/off for 64 FFT (4 pilots) and 32 FFT (2 pilots). – Second set of simulations is to directly compare the gap between 2 pilots and 4 pilots in 32 FFT. • Fix to 24 Data tones, compare the PER of 2 pilots, and 4 pilots. – The 4 pilot case is a “fake” scenario where 2 extra guard tones are used for pilots—just for a fair PER comparison (rule out impacts from different encoders, interleavers, etc). – Tx power is adjusted to make sure per-tone SNR is the same as the 2 pilot case, for a fair comparison. Submission Slide 21 Hongyuan Zhang, et. Al.

doc. : IEEE 802. 11 -11/1484 r 5 January 2012 AWGN, MCS 7, 2

doc. : IEEE 802. 11 -11/1484 r 5 January 2012 AWGN, MCS 7, 2 MHz Receiver Submission Slide 22 Hongyuan Zhang, et. Al.

doc. : IEEE 802. 11 -11/1484 r 5 January 2012 DNLOS, MCS 7, 2

doc. : IEEE 802. 11 -11/1484 r 5 January 2012 DNLOS, MCS 7, 2 MHz Receiver Submission Slide 23 Hongyuan Zhang, et. Al.

doc. : IEEE 802. 11 -11/1484 r 5 January 2012 DNLOS, MCS 7, 1

doc. : IEEE 802. 11 -11/1484 r 5 January 2012 DNLOS, MCS 7, 1 MHz Receiver Submission Slide 24 Hongyuan Zhang, et. Al.

doc. : IEEE 802. 11 -11/1484 r 5 January 2012 Discussions • • CFO

doc. : IEEE 802. 11 -11/1484 r 5 January 2012 Discussions • • CFO tracking effect by 2 pilots in 32 FFT is same or better than that with 4 pilots in 64 FFT. In 1 MHz, 4 pilots show some 0. 5~1 d. B PER gain over 2 pilots. When using 4 pilots in reality, Ntones becomes 22 tones, so peak throughput drops 8. 3%. It is then interesting to look at the “Goodput”: T = R*(1 -PER). – See next page, where the 2 pilots lead to higher goodput. • Assume select an MCS at 10% PER. • Assume 22+4 Tones case gets the same PER as the 24+4 Tones case we simulated—for the same per-tone SNR, i. e. ignore impacts from different coding and interleaving. • Limit to SNR range for MCS 5~7. Submission Slide 25 Hongyuan Zhang, et. Al.

doc. : IEEE 802. 11 -11/1484 r 5 January 2012 Cont’d • 2 Pilots

doc. : IEEE 802. 11 -11/1484 r 5 January 2012 Cont’d • 2 Pilots (24 Tones) shows higher goodput over 4 pilots (22 tones) at the considered SNR range, and considered channel. Submission Slide 26 Hongyuan Zhang, et. Al.