1. Response to 802.15.3 Coexistence Presentations
April 2007
doc.: IEEE /0570r0
May, 2009
Response to Coexistence Presentations
Date:
Authors:
Michelle Gong, Intel
Eldad Perahia, Intel Corporation

2. April 2007
doc.: IEEE /0570r0
May, 2009
Outline
Motivation
Architecture and Frame Format
802.11
What are needed to support CMS sync frames?
Conclusion
Michelle Gong, Intel
Eldad Perahia, Intel Corporation

3. May, 2009
Motivation
In the March IEEE meeting, Common Mode Signaling (CMS) sync frame defined in c was introduced as an inter-system coexistence mechanism
IEEE /0370r1
IEEE /0372r0
The goals of this presentation are:
To give a high level overview of and architectures and frame formats
To explain why TGad shouldn’t be required to support CMS sync frame
Michelle Gong, Intel

4. 802.15.3 Architecture May, 2009 PNC: PicoNet Coordinator
Neither PNC nor DEV bridges data for other DEVs. All data communications are within the piconet only
Michelle Gong, Intel

5. Fragmentation Control
May, 2009
MAC Frame Format
Octets: 2 2 1 1 3 1
0 or 4
Fragmentation Control
Stream Index
Frame Control
PNID
DestID
SrcID
Frame Payload
FCS
MAC header
MAC general frame header is 10 octets
2-octet PNID indentifies the piconet
PNID is generated by the PNC that starts the piconet
1-octet DEVID, i.e. DestID and SrcID
PNC assigns a DEVID to a DEV upon association
does not support data communication among different piconets
Therefore, a DEVID that can uniquely identify a DEV within the piconet is sufficient
Michelle Gong, Intel

6. May, 2009
Frame Header for 15.3c CMS
PHY header and MAC header are combined together
The parity check is performed over the combined header
Michelle Gong, Intel

7. May, 2009
Architecture
BSS: Basic Service Set
AP: Access Point
ESS: Extended Service Set
DS: Distribution System
DSS: Distribution System Service
IBSS: Independent BSS
Ad hoc networks such as IBSS, mesh, etc. define new sets of functionalities but they also maintain backward compatibility with the basic architecture
Michelle Gong, Intel

8. April 2007
doc.: IEEE /0570r0
May, 2009
MAC Frame Format
0 or
MAC data frame header is 30 or 36 octets long and increasing
It contains various control fields, a duration/ID field, and three or four address fields (pre-TGs)
The MAC address field contains the IEEE bit address
Each MAC address uniquely identifies a STA globally, which guarantees that each STA is uniquely addressable within the ESS
BSSID, set to the MAC address of the AP, is a globally unique identifier too
Michelle Gong, Intel
Eldad Perahia, Intel Corporation

9. May, 2009
PPDU Frame Format
PLCP Preamble
PLCP Header
MAC Header
Frame Body
FCS
Sent at basic rate
Sent at data rate
In , the PHY header and MAC header are modulated and coded separately (a fully layered approach)
The PLCP header identifies the duration of the packet to aid CCA
The PLCP header has its own parity check bit or CRC
Michelle Gong, Intel

10. TGad Functional Requirements
April 2007
doc.: IEEE /0570r0
May, 2009
TGad Functional Requirements
Functional requirements of TGad:
[Req9] The TGad amendment must maintain the network architecture of the system.
[Req10] The TGad amendment must maintain backward compatibility to management plane.
and its amendments define a rich set of management features that can be reused for 60GHz networks
802.11h/k/r/…
MAC
802.11/e/n
802.11/a/b/g/j/n/y
PHY
Michelle Gong, Intel
Eldad Perahia, Intel Corporation

11. In order to process the Sync frame, a TGad device would require
May, 2009
Decoding and Transmitting an c Sync frame requires a “dual-mode” device
In order to process the Sync frame, a TGad device would require
Support the CMS PHY
Support both the 15.3c and addressing schemes
Support both the 15.3c and frame formats
This is a “dual-mode” device
Michelle Gong, Intel

12. Distributed synchronization and scheduling are very hard problems
May, 2009
Distributed synchronization and scheduling are very hard problems
To utilize the sync frame solution, all co-located PNCs need to be synchronized and need to synchronize their schedules
Distributed synchronization is an NP-Complete problem
Centralized scheduling is an NP-Hard problem
Distributed scheduling is even more challenging due to the latency and overhead introduced by communication messaging and the fact that there is no single control entity
Directional transmission, the lossy nature of wireless media, and bursty traffic further complicate the problem
If associated DEVs do not support sync frames, coexistence is hard to achieve in some usage scenarios due to the hidden node problem
Need to evaluate the tradeoff between complexity and performance improvement in practical scenarios
Michelle Gong, Intel

13. May, 2009
Conclusion
As defined in TGad’s functional requirements, TGad needs to maintain the frame format and addressing scheme
As an amendment to , the TGad amendment must maintain the network architecture of the system, e.g. infrastructure basic service set, extended service set, access point, and station.
Furthermore the system must maintain backward compatibility to management plane, e.g. association, authentication, security, measurement, capability exchange, and MIB.
Due to the differences in and , architectures, frame formats and addressing schemes, TGad spec will be different from the 15.3c spec
TGad should not be required to support CMS sync frame
Michelle Gong, Intel