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doc.: IEEE 11-11-0172-00-000s
Submission
January 2011
Dee Denteneer, PhilipsSlide 1
MCCAOP Advertisement discussion
Date: 2011-01-19
Name Affiliations Address Phone email Dee Denteneer Philips HTC 35-1.57; 5656
AE Eindhoven; The Netherlands
+ 31 40 27 49743
Guido Hiertz Philips Riedel Communications GmbH & Co. KG, Uellendahler Str. 353, 42109 Wuppertal, Germany
+49-202-292-9987
Michael Bahr Siemens AG, Corporate Technology
Otto-Hahn-Ring 6 80200 München, Germany
Authors:
doc.: IEEE 11-11-0172-00-000s
Submission
January 2011
Dee Denteneer, PhilipsSlide 2
Abstract
This presentation provides a perspective on the MCCA comments received during the recirculation and specifically zooms in on the MCCAOP advertisement mechanism as in the Draft 8.0 and provides a tentative route towards a solution.
doc.: IEEE 11-11-0172-00-000s
Submission
Overview
• MCCA comments: 40– More or less editorial: 23 (will do my best)
– Advertisements: 17 (this presentation)
• Concerning the Advertisements– Terminology
– Completeness• When are advertisement elements part of the ‘same’ advertisement
– Teardown of reservations
– ‘Partial ‘ advertisements
January 2011
Dee Denteneer, PhilipsSlide 3
doc.: IEEE 11-11-0172-00-000s
Submission
Current structure
January 2011
Dee Denteneer, PhilipsSlide 4
doc.: IEEE 11-11-0172-00-000s
Submission
Suggested modification
• Add an Advertisements Set Sequence Number– As per 814r1
– Groups together a number of Advertisement elements
• Add an MCCAOP Advertisements Overview element– Contains a Advertisements Set Sequence Number
– Contains a bitmap, indicating which Advertisement elements are available in the current Advertisment Set
January 2011
Dee Denteneer, PhilipsSlide 5
doc.: IEEE 11-11-0172-00-000s
Submission
Proposed data structure, changes to current
January 2011
Dee Denteneer, PhilipsSlide 6
B7 B8 B15
B16 B17 B18 B19 B20 B21
MCCA Access Fraction
MCCA Access Fraction Limit
Accept Reservations
Advertisement Set Sequence
Number
TX-RX Report Present
Broadcast Report Present
Interfering Report Present
Last Advertisement
Advertisement Identifier
Bits: 8 8 1 1 1 1 1 4
* MCCA Information field
doc.: IEEE 11-11-0172-00-000s
Submission
Proposed structure, Advertisements Overview element
January 2011
Dee Denteneer, PhilipsSlide 7
Element ID Length Advertisements Set
Sequence Number
Accept Reservations
MAF MAF limit Active Advertisements Bitmap
Octets: 1 1 1 1 1 1 2
Figure s29—MCCAOP Advertisements Overview element
Advertisements Element 1 Active
Advertisements Element 2 Active
……. Advertisements Element 16 Active
Bits1 2 3:15 16
Figure s29—Active Advertisements Bitmap field
The Advertisements Elements n Active indicates which of the advertised Advertisement elements with the same set sequence number are part of the current Advertisement Set
doc.: IEEE 11-11-0172-00-000s
Submission
Functionality
• The set of tracked MCCAOP reservations is distributed over Advertisement elements
• Each Advertisement element has a 4 bit identifier and contains reports that contain the reservations
• The advertisement set sequence number groups the Advertisements elements• The overview element is regularly transmitted and acts as a key to validate
completeness• Given a Advertisement Set Sequence Number, limited changes are allowed to
the Advertisement Set– An element can be retrieved, indicated in the Overview element– An element can be added, indicated in the Overview element– However, an element cannot be changed– Once a bit for an advertisement element has been set to 1 and afterwards set to
0, it may never been set to 1 again with the same Advertisement Set Sequence Number
January 2011
Dee Denteneer, PhilipsSlide 8
doc.: IEEE 11-11-0172-00-000s
Submission
Functionality
• A complete overhaul of the distribution of reservations over the Advertisements elements is possible by increasing the Advertisement Set Sequence Number. This invalidates all Advertisement elements with an older Sequence number
• However, given an advertisement element with the right sequence number, and that is still indicated in the bitmap as active, a mesh STA knows this Advertisement element is still ok
• Enhanced Advertisements Request possible
– Request the Overview
– Request a specific set of elements
– Request the delta given your own bitmap
January 2011
Dee Denteneer, PhilipsSlide 9
doc.: IEEE 11-11-0172-00-000s
Submission
Reflection
• We now discuss how this scheme meets the objections raised in the comments
January 2011
Dee Denteneer, PhilipsSlide 10
doc.: IEEE 11-11-0172-00-000s
Submission
Terminology (cf. 11-10/814r1)
• advertisement set: Set of all Reservations to be advertised equals All tracked reservation
• Distributed over multiple Advertisement elements
– Use advertisement set sequence number to group these
– Index each Advertisement Element
• An advertisement equals the transmission of all (complete), active Advertisement elements and the advertisement overview element
• Advertisement frames may carry zero or more Advertisement elements and one or zero overview element
January 2011
Dee Denteneer, PhilipsSlide 11
BroadcastTimes
TX-RXTimes
InterferingTimes
Tracked MCCAOP Reservations
doc.: IEEE 11-11-0172-00-000s
Submission
Completeness
• The Advertisement Overview element is a key to the current Advertisement Set of a mesh STA
• A mesh STA can easily check the completeness of its picture of the Advertisement Set of a neighbor by using the Advertisements Overview element
• A mesh STA can simply request a delta to complete its picture of the Advertisement Set of a neighbor
January 2011
Dee Denteneer, PhilipsSlide 12
doc.: IEEE 11-11-0172-00-000s
Submission
Teardown
• A mesh STA can easily teardown the reservations in a Advertisement element by setting the corresponding bit in the bitmap to zero
• To teardown individual reservations you could delete one Advertisement element and advertise a new Advertisement element
• Note: Once an advertised reservation needs to be advertised, there are two choices:– Increase Sequence number, retransmit everything
– If a “bit” in the bitmap has not been used before, the element that contains the changed reservation can be placed in a new “bit” and the old bit is invalidated (aka set to 0).
January 2011
Dee Denteneer, PhilipsSlide 13
doc.: IEEE 11-11-0172-00-000s
Submission
Partial Advertisements
• Advertisements are by nature partial, so this notion can be deleted
• New reservations can simply be advertised by transmitting a new Advertisement element and setting the corresponding bit to 1 in the Advertisements Overview element
January 2011
Dee Denteneer, PhilipsSlide 14
doc.: IEEE 11-11-0172-00-000s
Submission
Possible further changes
• Is it clever to include several “reports” in one Advertisement element, or rather: have the elements typed (i.e. this gives an extra hierarchical level in the data structure)
• Even further, do we need elements to group reservations, or do we rather wotk with the individual reservations
January 2011
Dee Denteneer, PhilipsSlide 15
doc.: IEEE 11-11-0172-00-000s
Submission
Advertisement element, possible simplifcation
January 2011
Dee Denteneer, PhilipsSlide 16
Element ID Length Advertisement Element Information
Reservation 1 …….. Reservation n
Octets: 1 1 3 5 5 5
Figure s29—MCCAOP Advertisements element
Set Sequence number
Number of reservations
Advertisement type Advertisement Element Index
Bits1:8 9:16 17:18 19:24
Figure s29—Advertisements Element Information
Note: dispense of the “Report level”, give a type to the Advertisement element
Allows for 64 Advertisement elements and needs a larger bitmap in the overview element
Note: could also index and type the reservations themselves
doc.: IEEE 11-11-0172-00-000s
Submission
January 2011
Dee Denteneer, PhilipsSlide 17
References
• 11-10/814r1 „MCCAOP Advertisements“– contains normative text implementing these ideas
• IEEE 802.11s D8.0
