December 2017 doc.: IEEE 802.11-17/1834r0
IEEE P802.11
Wireless LANs
Date: 2017-12-5
Author(s):
Name / Affiliation / Address / Phone / email
Hiroyuki Motozuka / Panasonic / 600 Saedo-cho, Tsuzuki-ku, Yokohama, Kanagawa, Japan /
Takenori Sakamoto /
Yutaka Murakami /
Lei Huang /
Gaius Wee /
Kazu Takahashi /
SungJin Park / LG electronics /
Editor: modify the text in subclause 30.3.3.2.4.2 of D1.0 as follows:
30.3.3.2.4.2 Example of spoofing algorithm for Length field
The following is an informative algorithm for calculating the value of the Length field, Length, and the Training Length field, Training_Length, in the L-Header of an EDMG SC mode PPDU or an EDMG OFDM mode PPDU.
a) The tentative number of SC symbol blocks, NBLKS', is calculated as NBLKS'=TXTIME- TSTF+ TCE+ THeader-64×Tc 512 × Tc,
where TXTIME is defined in 30.12.3, and TL-STF, TL-CEF and TL-Header are defined in 30.5.10.4.2.2 for an EDMG SC mode PPDU and in 30.6.X8.Y3 for an EDMG OFDM mode PPDU.
b) The Base MCS field in the L-Header is set to the value such that the following conditions are met:
¾ NBLKS'≤218-1×8/NCBPB× Rρ-1,
where NCBPB, R and ρ are the parameters defined in section 20.6.3.2.5, 20.6.3.2.3 and 20.6.3.2.3 respectively, and the values are chosen based on the value of the Base MCS field as described in section 20.6.3.
¾ If NBLKS'3=1 and NBLKS'<38, the Base MCS field shall be set to the value that is greater than 5.
c) The parameters NBLKS and NTRN which denote the number of SC symbol blocks, NBLKS, and the value of the Training Length field, NTRN, respectively in a DMG SC mode PPDU with the same TXTIME as the EDMG PPDU are calculated as follows:
If the Base MCS > 5 (QPSK, and 16-QAM and 64-QAM)
NBLKS=NBLKS'
NTRN=0
End
If the Base MCS ≤ 5 (BPSK) and NBLKS'≥38
If mod(NBLKS',3)≠1
NBLKS=NBLKS'
NTRN=0
Else
NTRN=2, and NBLKS are is calculated as follows:
If 0<TXTIME- TSTF+ TCE+ THeader-64×Tc Tcmod512≤256
NBLKS=NBLKS'-20
Else
NBLKS=NBLKS'-19
End
End
End
d) The maximum length of PSDU Length value that fulfills the requirement for the spoofing error specified in 30.3.3.2.4.1, Lengthmax, is calculated as
Lengthmax = NBLKS NCBPBLCW LCW8 Rρ,
where LCW is the parameter defined in section 20.6.3.2.3, and the value is chosen based on the value of the Base MCS field as described in section 20.6.3.
e) The spoofed values of the Length and Training Length fields with of anthe EDMG PPDU with compressed BW is are calculated as follows:
If ≥compressed_bw
Length = Lengthmax32⋅32+compressed_bw
Else
Length = Lengthmax32-1⋅32+compressed_bw
End
= NTRN
where the parameter compressed_bw is the value of the Compressed BW field in the L-Header as described in 30.3.3.2.4.1.
When the Base MCS field is set to 1, the calculated length may not satisfy the requirement for the spoofing error defined in エラー! 参照元が見つかりません。30.3.3.2.4.1. In that case, the Base MCS field shall be set to a value different than from 1, and the Length and the Training Length fields shall be calculated by repeating c) to e).
Editor Note: there are many parameters in the above algorithm that are undefined. Examples include compressed_bw, R, ρ, etc. All these need to be defined. Also, the mod function does not comply with how it is defined in the 802.11 std.
Straw Poll:
• Do you agree to accept the text changes proposed in 11-17/aaaar0 proposed text change on example of spoofing algorithm?
References
[1] Draft P802.11ay D1.0
Submission page 1 Hiroyuki Motozuka (Panasonic)