Transcript 19-07-0003-00-0000-SEAMCAT-A-Tool-for-coordination-between-technologies.ppt

January 2007
doc.: IEEE 802.19-07/0003r0
SEAMCAT – A Tool for Coordination
Between Technologies
Date: 15-01-2006
Authors:
Name
Company
Address
Phone
email
Mark Austin
Ofcom
+4420 7783
4364
mark.austin@ofcom.org.uk
Peter Spital
Ofcom
2a Riverside House,
Southwark Bridge Road,
London,
SE1 9HA , UK
2a Riverside House,
Southwark Bridge Road,
London,
SE1 9HA , UK
+4420 77830
4369
Peter.Spital@ofcom.org.uk
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Submission
Slide 1
Mark Austin and Peter Spital, Ofcom
January 2007
doc.: IEEE 802.19-07/0003r0
Spectrum
Engineering
Advanced
MonteCarlo
Analysis
Tool
A Tool
for
Coordination Between Technologies
Submission
Slide 2
Mark Austin and Peter Spital, Ofcom
January 2007
doc.: IEEE 802.19-07/0003r0
Sharing methods:
• Spacing radio systems in frequency
– Guard bands
• Spacing geographically
– Using the gaps between intended deployment areas
• Power and Location
– Using appropriate technology in appropriate locations
Submission
Slide 3
Mark Austin and Peter Spital, Ofcom
January 2007
doc.: IEEE 802.19-07/0003r0
Defining the sharing rules:
• Analytical analysis, usually by worst-case approach:
– Minimum Coupling Loss (MCL) method, to establish rigid rules
for minimum “separation”
• Statistical analysis of random trials:
– The Monte-Carlo method, to establish probability of interference
for a given realistic deployment scenario
Submission
Slide 4
Mark Austin and Peter Spital, Ofcom
January 2007
doc.: IEEE 802.19-07/0003r0
MCL principle:
• The stationary worst-case is assumed
Wanted
Signal
Victim
Interferer
Dmin, or minimum frequency separation for D=0
– However such worst-case assumption will not be permanent during
normal operation and therefore, for mobile technologies, sharing
rules tend to be unnecessarily stringent
Submission
Slide 5
Mark Austin and Peter Spital, Ofcom
January 2007
doc.: IEEE 802.19-07/0003r0
Monte-Carlo principle:
• Repeated random generation of interferers and their
parameters (activity, power, etc…)
Wanted
Signal
t=t0
Victim
t=ti
t=t1
Active
Interferer
Inactive
Interferer
– After many trials not only unfavourable, but also favourable cases will
be included. Reveals the service experienced by the user.
Submission
Slide 6
Mark Austin and Peter Spital, Ofcom
January 2007
doc.: IEEE 802.19-07/0003r0
Monte-Carlo assumptions:
• User will need to define the distributions of various
input parameters, e.g.:
– How the power of interferer varies (PControl?)
– How the interferer’s frequency channel varies
– How the distance between interferer and victim varies, and many
others
• If all of the variables in all of the trials are equally
probable.
– Results will inevitably reflect user experience
Submission
Slide 7
Mark Austin and Peter Spital, Ofcom
January 2007
doc.: IEEE 802.19-07/0003r0
SEAMCAT:
• Spectrum Engineering Advanced Monte-Carlo
Analysis Tool
• An open, free software tool for analysing the coexistence of radio systems
• Developed by engineers for use by administrators
• Supported by CEPT
• Maintained by the ERO
Submission
Slide 8
Mark Austin and Peter Spital, Ofcom
January 2007
doc.: IEEE 802.19-07/0003r0
SEAMCAT:
• User defines a scenario, describing mutual positioning
of two systems, in geographical domain…
5 km
MS-Iti
Wti
Wr
BS-Vr
…as well as many other parameters:
Submission
Slide 9
Mark Austin and Peter Spital, Ofcom
January 2007
doc.: IEEE 802.19-07/0003r0
Scenario parameters:
•
•
•
•
•
Positioning of two systems in frequency
Powers
Masks
Activity
Etc.
Submission
Slide 10
Mark Austin and Peter Spital, Ofcom
January 2007
doc.: IEEE 802.19-07/0003r0
SEAMCAT event generator:
• Random generation of transceivers
• Link budget
• Signal values
Submission
Slide 11
Mark Austin and Peter Spital, Ofcom
January 2007
doc.: IEEE 802.19-07/0003r0
How event generator works:
• Succession of snapshots…
dRSS
iRSS
Snapshot#
WT
1) Calculate d, Ptx, GaTx, GaRx, L
Snapshot#
2) Calculate dRSSi
IT
WT
VR
1) Calculate d, Ptx, GaTx, GaRx, L
2) Calculate iRSSi
VR
1) Calculate d, Ptx, GaTx, GaRx, L
2) Calculate received signal, if PC, adjust Ptx
IT
WR
WR
Submission
Slide 12
Mark Austin and Peter Spital, Ofcom
January 2007
doc.: IEEE 802.19-07/0003r0
Result of simulations:
• Vectors for wanted and interfering signals:
Submission
Slide 13
Mark Austin and Peter Spital, Ofcom
January 2007
doc.: IEEE 802.19-07/0003r0
Evaluating interference:
• By comparing signal instances:
- For each random event:
Desired signal value (dBm)
Interfering signal (dBm)
C/Itrial > C/Itarget?
Interference (dB)
Noise Floor (dBm)
- If C/Itriali >C/Itarget: “good” event
- If C/Itriali <C/Itarget: “interfered”
- Finally, after cycle of Nall events:
Overall Pinterference= 1- (Ngood/Nall)
Submission
Slide 14
Mark Austin and Peter Spital, Ofcom
January 2007
doc.: IEEE 802.19-07/0003r0
SEAMCAT-3 (2005):
• CDMA:
Submission
Slide 15
Mark Austin and Peter Spital, Ofcom
January 2007
doc.: IEEE 802.19-07/0003r0
SEAMCAT-3:
• Interference into CDMA as capacity loss:
Submission
Slide 16
Mark Austin and Peter Spital, Ofcom
January 2007
doc.: IEEE 802.19-07/0003r0
OFDM Modelling
• A new Feature for SEAMCAT
• Recognises the demand for mobile OFDM modelling.
Builds on the proven capability of SEAMCAT
• Supported by:
– CEPT Working Group SE
– SE7, the Land Mobile Working Group
– Qualcomm.
Submission
Slide 17
Mark Austin and Peter Spital, Ofcom
January 2007
doc.: IEEE 802.19-07/0003r0
OFDMA
• The mobile variant of OFDM
• Key features:
– Multiple slots per user
– Sub-slot hopping on either a single symbol or a small group of
symbols
– Forward error correction over multiple symbols
– Fast adjustment of Modulation and FEC
Submission
Slide 18
Mark Austin and Peter Spital, Ofcom
January 2007
doc.: IEEE 802.19-07/0003r0
Key Assumptions
• Interference assumed to be corrected across multiple
sub-slots by the forward error correction
• Mean data rate is assumed to be dependent on the
mean C/I
• Segment is short enough that the modulation and
forward error correction can rapidly respond to
changing C/I.
Submission
Slide 19
Mark Austin and Peter Spital, Ofcom
January 2007
doc.: IEEE 802.19-07/0003r0
Basis of Methodology
• For each snapshot:
–
–
–
–
The users will be randomly distributed
The users will be assigned to a base station
The C/I ratio for each terminal will be calculated
The required modulation and error correction will be looked up
• When the system is stable interference is applied
– The effect on the C/I ratio will be calculated
Submission
Slide 20
Mark Austin and Peter Spital, Ofcom
January 2007
doc.: IEEE 802.19-07/0003r0
Measuring the Results
• The output of the model will include:
– Number of terminals unable to connect because of cell overload
– Number of terminals unable to achieve required C/I before
interference
– Number of additional terminals rejected after interference
– Data rate before and after interference
Submission
Slide 21
Mark Austin and Peter Spital, Ofcom
January 2007
doc.: IEEE 802.19-07/0003r0
Testing the Concept
• Bespoke software have been used for Flash OFDM and
WiMAX
– Flash OFDM performance similar to real network
• Models revealed that customer outage is a more
sensitive indicator of performance than data rate
Submission
Slide 22
Mark Austin and Peter Spital, Ofcom
January 2007
doc.: IEEE 802.19-07/0003r0
New Variants of OFDM
• Certain that use of OFDM will increase
• TDD variants can use ‘old’ SEAMCAT
• Technology specific plug-ins planned to permit easy
adoption of future OFDMA implementations.
– New plug-ins would be obtained by modifying existing plug-ins
Submission
Slide 23
Mark Austin and Peter Spital, Ofcom
January 2007
doc.: IEEE 802.19-07/0003r0
SEAMCAT
•
•
•
•
•
•
Proven
Maintained
Supported by the ERO
Flexible
Optimised for Land Mobile use
An Open Technology on an Open Software platform
Submission
Slide 24
Mark Austin and Peter Spital, Ofcom
January 2007
doc.: IEEE 802.19-07/0003r0
SEAMCAT
• A Solution for the Future
• Collect it from:
– http://www.seamcat.org/
• Thank You
Submission
Slide 25
Mark Austin and Peter Spital, Ofcom