1. DMG Base MCS and Length Supplementary Slides
May 2016
doc.: IEEE /0707r0
May 2016
DMG Base MCS and Length Supplementary Slides
Date:
Authors:
Hiroyuki Motozuka, Panasonic
Hiroyuki Motozuka, Panasonic

2. May 2016
doc.: IEEE /0707r0
May 2016
Abstract
The current text in draft D5.3 of REVmc defines the Base MCS and Length field in the PHY SC header for extended MCS.
But the formula for Length field value causes duration calculation error for some Ns (number of PSDU octets.)
The submission 11-16/0670r2 proposes modified text to fix it.
This submission includes supplementary slides for /0670r2.
Hiroyuki Motozuka, Panasonic
Hiroyuki Motozuka, Panasonic

3. duration calculation error
May 2016
doc.: IEEE /0707r0
May 2016
duration calculation error
STAs without Extended SC MCS support miscalculate the PPDU duration for some Ns (number of octets).
Such error may cause potential risks for fairness and interoperability on backoff procedures.
Actual MCS
Actual PPDU duration
MCS9.1
N = 70
Preamble/Header
Payload
3.09 usec
Header value (Spoofed)
Calculated PPDU duration
MCS6
Length 40
Preamble/Header
Payload
formula on REVmc D5.3
2.80 usec
+0.29 usec
duration error
-0.58us ~ 0.29us
Hiroyuki Motozuka, Panasonic
Hiroyuki Motozuka, Panasonic

4. Proposed Modification - MCS
May 2016
doc.: IEEE /0707r0
May 2016
Proposed Modification - MCS
MCS 6 to 12 are used for spoofing in natural (ascending) order
Extended MCS
value in MCS field
9.1 6
12.1 7
12.2 8
12.3 9
12.4 10
12.5 11
12.6 12
Hiroyuki Motozuka, Panasonic
Hiroyuki Motozuka, Panasonic

5. Proposed Modification - Length
May 2016
doc.: IEEE /0707r0
May 2016
Proposed Modification - Length
Based on number of symbol blocks
Avoid error caused by number of parity bits
Hiroyuki Motozuka, Panasonic
Hiroyuki Motozuka, Panasonic

6. Proposed Modification - SI
May 2016
doc.: IEEE /0707r0
May 2016
Proposed Modification - SI
Additional information to recover actual number of octets in PPDU is transmitted with 2bits of SI (Similar to [2] 11-16/0220r3)
Hiroyuki Motozuka, Panasonic
Hiroyuki Motozuka, Panasonic

7. References [1] Draft P802.11REVmc_D5.3
May 2016
doc.: IEEE /0707r0
May 2016
References
[1] Draft P802.11REVmc_D5.3
[2] 11-16/0220r3 Clause 20 SC MCS Extension
[3] 11-16/0233r0 Additional SC MCSs in clause 20 (DMG PHY)
[4] 11-16/0670r2 Base MCS and Length Calculation for Extended MCS Set
Hiroyuki Motozuka, Panasonic
Hiroyuki Motozuka, Panasonic