1. May 2009
Project: IEEE P Working Group for Wireless Personal Area Networks (WPANs)
Submission Title: [ 1-octet MAC Header frame types ]
Date Submitted: [ 12 May 2009 ]
Source: [ Michael Bahr, Rene Struik ] Company [Siemens AG, Certicom]
Address [ Siemens AG, Corporate Technology, Otto-Hahn-Ring 6, München, Germany ]
Voice:[ ], FAX: [ ], [bahr et siemens dod com, ]
Re: [ ]
Abstract: [ The document gives information on the possible proposed representations of MAC frames with a MAC header of 1 octet. Especially, it looks at the question of how the frame type(s) should be defined. ]
Purpose: [ Provide detailed information on the frame type representation of 1-octet MAC headers in order to make an informed decision. ]
Notice: This document has been prepared to assist the IEEE P It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein.
Release: The contributor acknowledges and accepts that this contribution becomes the property of IEEE and may be made publicly available by P
M. Bahr (Siemens AG, CT), R. Struik (Certicom)

2. Short Frame Control Field vs. Shortened Frame Control Field
May 2009
doc.: IEEE <doc#>
May 2009
Short Frame Control Field vs. Shortened Frame Control Field
How to define
the frame types and bits of a
one-octet MAC header?
M. Bahr (Siemens AG, CT), R. Struik (Certicom)
M. Bahr (Siemens AG, CT), R. Struik (Certicom)

3. doc.: IEEE 802.15-<doc#>
May 2009
doc.: IEEE <doc#>
May 2009
Short and Shortend FCF
MAC-Header of 2 Byte (short Frame Control, Sequence Number)
Proposal by Security/Overhead Reduction (S-OR) Subgroup
doc 15-09/0233r2
MAC-Header of 1 Byte (shortened Frame Control)
Proposal by Factory Automation (FA) Subgroup
doc 15-09/0228r0
M. Bahr (Siemens AG, CT), R. Struik (Certicom)
M. Bahr (Siemens AG, CT), R. Struik (Certicom)

4. Frame Format S-OR-Proposal FA-Proposal May 2009
M. Bahr (Siemens AG, CT), R. Struik (Certicom)

5. Frame Control Subfields
May 2009
Frame Control Subfields
S-OR-Proposal
0-1: Frame Type
2: Short Frame Control Field
3: Security
4: Frame Pending
5: ACK Request
6: reserved (might be used for frame type extension)
7: Frame Version
FA-Proposal
0-2: Frame Type
3-5: some non-specified bits
bit 3: Security
bit 4: Frame Version
bit 5: ACK Request
6-7: Sub Frame Type
M. Bahr (Siemens AG, CT), R. Struik (Certicom)

6. Usage of Frame Types S-OR-Proposal no remaining reserved frame type
May 2009
Usage of Frame Types
S-OR-Proposal
no remaining reserved frame type
FA-Proposal
3 remaining reserved frame types
Frame Type Value
b2 b1 b0
Description
000
Beacon
001
Data
010
Acknowledgement
011
MAC Command
100
Beacon sFCF
101
Data sFCF
110
Acknowledgement sFCF
111
MAC Command sFCF
Frame Type Value
b2 b1 b0
Description
000
Beacon
001
Data
010
Acknowledgement
011
MAC Command
100
MAC frame with sFCF
101
Reserved
110
111
M. Bahr (Siemens AG, CT), R. Struik (Certicom)

7. Frame Processing Considerations
May 2009
Frame Processing Considerations
S-OR-Proposal
case bit b2 do 0:
case frame type do
000: beacon
001: data
010: ack
011: command 1:
sFCF processing
FA-Proposal
case frame type do
000: beacon
001: data
010: ack
011: command
100: sFCF processing
M. Bahr (Siemens AG, CT), R. Struik (Certicom)

8. Room for Future Extensions
May 2009
Room for Future Extensions
S-OR-Proposal
bit 6 can be used for new frame types
Frame Version can be used for new frame types
theoretically 44 new frame types possible
2 unused frame versions * 2 reserved bits in first 4 frame types + 1½ unused frame version * 1 reserved bit in last 4 frame types
practically, the official frame type cannot be changed
only beacon, data, ack, command can be redefined via Frame Version and reserved bits
FA-Proposal
3 remaining reserved frame types
can have as many sub frame types as possible
theoretically 3 * 2(5+8*126) new frame types possible
practically the number of sub frame types might be in the range of 4 to 16 per frame type.
any new frame type can be defined (e.g. GACK frame, backup beacon frame, Montreal Bagel Frame)
M. Bahr (Siemens AG, CT), R. Struik (Certicom)

9. The Trade Off  available bits in one-octet MAC header/ Frame Control
May 2009
The Trade Off
available bits in one-octet MAC header/ Frame Control
extensibility for future frame types 
M. Bahr (Siemens AG, CT), R. Struik (Certicom)

10. May 2009
Straw Poll / Motion
Which definition for a one-octet MAC header / Frame Control (sFCF) do you prefer?
a) using the last four available frame type values for four frame types (beacon, data, ack, command) with sFCF and having 5 bits available (S-OR proposal)
b) using one of the four available frame type values as indicator for sFCF and four sub frame types within this frame type (beacon, data, ack, command) and having 3 bits available (FA proposal)
results:
option a / b:
M. Bahr (Siemens AG, CT), R. Struik (Certicom)