August 2006
doc.: IEEE 802.22-06/0156r0
Superframe Structure
IEEE P802.22 Wireless RANs
Date: 2006-08-15
Authors:
Name
Company Address
Phone
email
Carlos Cordeiro
Philips
USA
914-945-6091
Monisha Ghosh
Philips
USA
914-945-6415
Carlos.Cordeiro@philip
s.com
Monisha.Ghosh@philip
s.com
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>
Submission
Slide 1
Carlos Cordeiro, Philips
August 2006
doc.: IEEE 802.22-06/0156r0
Introduction
• The purpose of this presentation is to provide further
clarification on the superframe structure adopted in the
current Draft 0.1 spec
• In this presentation we show that:
– Superframe allows the support of a number of advanced features,
NOT ONLY channel bonding
– Superframe allows the standard to be future proof
– Superframe can also be used for SINGLE CHANNEL only case
– Superframe overhead is negligible
Submission
Slide 2
Carlos Cordeiro, Philips
August 2006
doc.: IEEE 802.22-06/0156r0
Superframe Structure
• Superframes allow a number of advanced features to
be implemented
– For incumbent protection, so that quiet periods of overlapping
networks can be synchronized
– The self-coexistence mechanisms available in the current draft
depend on it
– The synchronization of overlapping 802.22 networks depend on it
• So, it is NOT all about channel bonding
– A great deal of the current draft 0.1 spec relies on the superframe
structure for a number of different things (please refer to the spec
for more info)
Submission
Slide 3
Carlos Cordeiro, Philips
August 2006
doc.: IEEE 802.22-06/0156r0
Superframe Structure: the General Case
– Capacity as
needed (up to
subscriber)
– Product
differentiation
– Controllable
by BS, etc.
...
Superframe n-1
Preamble
Frequency
• The MAC can
simultaneously
support single
channel and
multi-channel
CPEs
SCH
AW
Superframe n
frame 0
frame 1
Unit Channel
Preamble SCH AW
t-1
Unit Channel
Preamble SCH AW
t
Unit Channel
Preamble SCH AW
t+1
Frame
0
Frame
1
...
Frame
m
...
Superframe n+1
...
Preamble SCH
Frame
0
Preamble SCH
Frame
0
Preamble SCH
Frame
0
Time
frame m
Frame
2
Frame
1
Frame
2
...
Frame
2
Time
Submission
Slide 4
Carlos Cordeiro, Philips
August 2006
doc.: IEEE 802.22-06/0156r0
Superframe Structure: the Single Channel
case
• If only a single
channel is used,
the superframe
is transmitted
on that channel
only
...
Superframe n-1
Preamble
Superframe n
frame 0
SCH
...
Superframe n+1
frame 1
...
Time
frame m
• Plus, this allows
for future
extensions
Frequency
– No added
complexity
Unit Channel
Preamble SCH
t
Frame
0
Frame
1
...
Frame
n
Preamble SCH
Frame
0
Frame
1
Frame
2
...
Time
Submission
Slide 5
Carlos Cordeiro, Philips
August 2006
doc.: IEEE 802.22-06/0156r0
Superframe Structure in Numbers
• Superframe size is fixed at 160ms
– That is, a total of sixteen 10ms frames per superframe
• Superframe structure consumes only 3 OFDM symbols
for an entire superframe duration
– Short preamble + long preamble + superframe header
• If we consider the size of an OFDM symbol of about
373µs, this results in a negligible overhead of
approximately 0.70%!!!!
Submission
Slide 6
Carlos Cordeiro, Philips
August 2006
doc.: IEEE 802.22-06/0156r0
Conclusions
• The superframe structure allows for a number of advanced
features to be implemented
– A number of mandatory schemes in draft 0.1 depend on it
• We have shown that the superframe structure:
– Allows the support of a number of advanced features, NOT ONLY
channel bonding
– Allows the standard to be future proof
– Incurs negligible overhead of only 0.70%
– Can also be used for the SINGLE CHANNEL only case
• The superframe structure is currently mandatory
– This way, the standard is made future proof and compatible with future
amendments/enhancements
Submission
Slide 7
Carlos Cordeiro, Philips