March 2007 doc.: IEEE 802.11-07/0516r0
IEEE P802.11 Wireless LANs
LB97 COEX Comment Resolutions: 20/40 MHz Coexistence
Date: 2007-05-10
Author(s): Name Company Address Phone email 15435 Innovation Dr. Vinko Erceg Broadcom +1 858 521 5885 [email protected] San Diego, CA 92128 m Matthew Broadcom mfischer@broadcom. Fischer com
Abstract This submission suggests resolutions of LB97 COEX comments related to the sub-topic 20/40 MHz. The following CIDs are addressed: 186, 16, 18, 317, 318, 457, 460, 550, 715, 716, 717, 1740, 1830, 1831, 1832, 1867, 1937, 1938, 2465, 2466, 2467, 2468, 2830, 2964, 3257, 3271, 3272, and 3277.
CID 1832 and CIDs referred to it are covered in submission 11-07-0591r1. CIDs 1740, 1867, 3271, and 2468 are covered in submission 11-07-0614r0.
The changes marked in this document are based on TGn Draft 2.0
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Submission page 1 Vinko Erceg, Broadcom March 2007 doc.: IEEE 802.11-07/0516r0
CID Sec. Pg. Ln. Comment Proposal Proposed Resolution
186 9.20 163 23 20/40 Functional Provide a way for other Withdrawn by commenter description: When a 20 channel(s) to be used 3/14/07 MHz station is transmitting simultaneously with the or receiving on the primary primary channel in a BSS, channel, none of the other while observing virtual channels can be used for carrier sense on all other transmissions in the channels. The CCC MAC BSS. It is possible, makes this possible. It can however, to increase the be used in the 5 GHz band BSS throughput even alone and in both the 5 beyond what is achievable GHz and the 2.4 GHz by a 40 MHz channel if the bands together. MAC included the option for multichannel use, while respecting use of the same channels by OBSSs.
16 7.3.2.50 73 31 "- all STAs in the BSS are Change the cited part to "- Counter - see CID 20/40 MHz HT, or all STAs in the BSS are 1832, document 11-07- - in a 20/40 MHz BSS, or" 20/40 MHz HT STAs in a 0591r1. Correct this. 20/40 MHz BSS, or". 18 7.3.2.50 73 39 For 1, do non-HT STAs Change "if there may be Counter - see CID need to be in both the non-HT STAs in both the 1832, document 11-07- primary channel and the primary and the secondary 0591r1. secondary channel even if channel" to "if there may their presence is may? be non-HT STAs in the primary or the secondary channel". 317 7.3.2.50 73 32 "-in a 20/40 MHz BSS", clarify it. Counter - see CID unclear 1832, document 11-07- 0591r1. 318 7.3.2.50 73 38 "in both the primary and should be "in either the Counter - see CID the secondary channel", primary or the secondary 1832, document 11-07- incorrect channel" 0591r1. 457 7.3.2.50 73 32 "-in a 20/40 MHz BSS", clarify it. Counter - see CID unclear 1832, document 11-07- 0591r1. 460 7.3.2.50 73 38 "in both the primary and should be "in either the Counter - see CID the secondary channel", primary or the secondary 1832, document 11-07- incorrect channel" 0591r1. 550 7.3.2.50 73 38 The directions for the Change "both the primary Counter - see CID value 1 speak of "non-HT and the secondary" to 1832, document 11-07- STAs in both the primary "either the primary or the 0591r1. and the secondary secondary". channel." This says that if there are non-HT STAs in one channel, but not the other, then this protection signaling does not occur.
Submission page 2 Vinko Erceg, Broadcom March 2007 doc.: IEEE 802.11-07/0516r0
715 9.20.1 163 30 “operating in 20MHz Define 20MHz mode using Counter – delete the mode” – what is meant by PLME parameters or sentence. See also “20 MHz mode” MASK CID 2465: “Rules in this spec use the terms 20MHz capable and refer to the supported channel width set as synonyms. Now we're explicitly introducing the possibility that a STA can "lie" about its capabilities.”
Suggested resolution: Counter.
TGn Editor: on page 163, line 30, delete the following sentence:
“A 20/40 capable STA operating in 20 MHz mode follows the rules for a 20 MHz capable STA.”
716 9.20.1 163 32 "operates as defined in Please clarify Counter. Refer to CID 11.16" does it means that 2468, see submission the rules in the rest of this 11-07-0614r0. subclause (9.20) do not apply
717 9.20.1 163 35 “operates as defined in Please clarify Counter. Refer to CID 9.13.5” – does it mean 2468, see submission thet the rules in the rest of 11-07-0614r0. this subclause (9.20) do not apply
1740 9.20 163 23 add a statement that 9.20 As in comment Counter - text is and all subclauses only rewritten with newly applies to 20/40 capable defined terms to make STAs it explicit in each instance as to which STA the rules of behavior apply - see document 11-07- 0614r0.
1830 7.3.2.50 73 32 “-in a 20/40 MHz BSS”, clarify it. Counter - see CID unclear 1832, document 11-07- 0591r1.
Submission page 3 Vinko Erceg, Broadcom March 2007 doc.: IEEE 802.11-07/0516r0
1831 7.3.2.50 73 38 “in both the primary and should be “in either the Counter - see CID the secondary channel”, primary or the secondary 1832, document 11-07- incorrect channel” 0591r1.
1832 7.3.2.50 73 30 The rules to set operating Fix the inconsistency. Accept – changed to mode to 0 is incosistent Recommend descirbing the description as with the rules to set it to the use of the two bits found in document 11- none zero. For example, individually. 07-0591r1 and in the when all STAs in the BSS subsequent draft(s). are 20/40 MHz STAs, it should be set to 0. However, in the mean time there may be some non-HT STAs in other BSS in the primary channel therefore the operating bit should be set to 1 accordingly.
1867 9.20.1 163 38 The text “Otherwise, a It is NOT always possible Counter, see 20/40 capable STA shall to fully protect against submission 11-07- operate as defined in OBSS activities on the 0614r0. 9.20.2” implies that STAs secondary channel and as operating under PCO and such the HT STA must L-SIG TXOP protection always check for (as mentioned in the secondary CCA at the previous two paragraphs beginning of the TXOP in the same section) DO before it commences NOT need to comply with transmission. PCO and L- rules of section 9.20.2. SIG TXOP protection mechanism cannot avoid this condition/requirement.
Edit the text to reflect the requirement.
1937 7.3.2.50 73 30 Conditions for setting Clarify conditions for Counter - see CID Operating Mode to "0" are setting mode to "0". 1832, document 11-07- confusing. 0591r1.
1938 7.3.2.50 73 38 Intention is unclear for Change "in both the Counter - see CID mode "1" primary and secondary 1832, document 11-07- channel" to "in either the 0591r1. primary or secondary channels"
Submission page 4 Vinko Erceg, Broadcom March 2007 doc.: IEEE 802.11-07/0516r0
2465 9.20.1 163 30 "follows the rules for a 20 I think the easiest solution Accept. Implemented in MHz capable STA." is to remove the quoted CID 715. line. This is awkward. Rules in this spec use the terms 20MHz capable and refer to the supported channel width set as synonyms. Now we're explicitly introducing the possibility that a STA can "lie" about its capabilities.
It's also inconsistent with the definition in table n25.
The result is that roughly half the statements in the spec now need to be rewritten to say, "A 20 MHz capable STA, or a 20/40 MHz Capable STA that sets it Supported Channel Width set to 0 ..."
Suggested resolution: Accept. Implemented in CID 715.
2466 9.20.1 163 30 “A 20/40 capable STA” Add a definition of this Counter. Delete the term, or relate to existing sentence. Implemented There is no definition of 5ignaling. in CID 715. this term
Suggested resolution: Counter. Implemented in CID 715.
2467 9.20.1 163 30 "operating in 20 MHz Replace with "that sets its Counter. Delete the mode" - relate to existing Supported Channel Width sentence. Implemented signalling Set field in the HT in CID 715. Capabilities element to 0"
Suggested resolution: Counter. Implemented in CID 715.
Submission page 5 Vinko Erceg, Broadcom March 2007 doc.: IEEE 802.11-07/0516r0
2468 9.20.1 163 35 “A 20/40 capable STA I think we need to Counter, see operating under L-SIG establish clearly which of submission 11-07- TXOP protection operates the rules in 9.20.2 are only 0614r0. as defined in 9.13.5 (L- operated if you are not SIG TXOP PCO and are not L-SIG protection).Otherwise, a and then find a way to 20/40 capable STA shall represent this exclusivity operate as defined in here. 9.20.2 (STA CCA sensing 20/40 MHz BSS) to 9.20.4 Needs a submission. (Switching between 40 MHz and 20 MHz).”
This appears to excuse a STA using L-SIG TXOP protection from anything in 9.20.2-9.20.4, including, for example, the need to operate the “intolerant” bit.
Same comment for the previous line on PCO operation.
2830 7.3.2.50 73 33 The definition of the Replace the "— all STAs Counter - see CID operating mode =0 is not in the BSS are 20/40 MHz 1832, document 11-07- clear and looks like typo HT, or 0591r1. — in a 20/40 MHz BSS, or" by " — all STAs in the 20/40 BSS are 20/40 MHz HT, or"
2964 9.13.1 127 46 20-40MHz Coexistence: Maintain definition of Reject. Reason for non-HT duplicate and HT 40MHz operation in the rejection: coexistence duplicate (MCS 32) modes 5GHz band but preclude it mechanism are defined do not work properly in from the 2.4GHz Band in Sections 7, 9, and 11 2.4GHz due to channel that allow for proper spacing that is not sharing of spectrum centered on 20MHz between 20 MHz and (normally 25MHz, i.e. 40 Mhz devices in 2.4 channels 1,6,11.) GHz.
3257 9.20.4 164 32 Need to add allowance to Make the change Accept. Implemented in transmit control types in indicated in the comment. CID 3272. secondary channel
Suggested resolution: Accept. Implemented in CID 3272.
3271 9.20 make a reference to Make the change Counter - rewrite of 11.9.8.3 Scanning prior indicated in the comment. 9.20 per submission to… -- there are additional 11-07-0614r0 removes rules about 20/40 MHz the need for this BSS operation in that reference. subclause
Submission page 6 Vinko Erceg, Broadcom March 2007 doc.: IEEE 802.11-07/0516r0
3272 9.20.4 164 32 Allow alternative 20/40 Change "A non-AP STA Accept. coexistence mechanisms. that is a member of a 40 MHz BSS shall not transmit 20 MHz frames in the secondary channel." to "A non-AP STA that is a member of a 40 MHz BSS shall not transmit non- Control type 20 MHz frames in the secondary channel."
Suggested resolution: Accept.
TGn Editor: on page 164, line 32-33, modify the sentence as follows:
“A non-AP STA that is a member of a 40 MHz BSS shall not transmit non-Control type 20 MHz frames in the secondary channel.”
3277 9.20 163 38 wrong preposition - "to" change "to" to "through" Accept means up to the beginning of that item, "through" means up to the end of that item
Suggested resolution: Accept.
TGn Editor: on page 163, line 38, modify the sentence as follows:
“Otherwise, a 20/40 capable STA shall operate as defined in 9.20.2 (STA CCA sensing 20/40 MHz BSS) to through 9.20.4 (Switching between 40 MHz and 20 MHz).”
Submission page 7 Vinko Erceg, Broadcom