1. Introduction to SEAMCAT
European Communications Office
Jean-Philippe Kermoal - SEAMCAT Manager (ECO)
October 2010
EUROPEAN
COMMUNICATIONS
OFFICE
Nansensgade 19
DK-1366 Copenhagen
Denmark
Telephone:
Telefax:
Web Site:
Jukka Rakkolainen/ERO

2. Outline Part 1 - Why SEAMCAT? Part 2 - SEAMCAT-3 software tool
Part 3 - Principles of modelling various systems:
Traditional – SEAMCAT 3.2.X
CDMA – SEAMCAT 3.2.X
Part 4 - SEAMCAT information
Conclusions

3. Part 1: Why SEAMCAT?

4. Spectrum engineering challenges
increasing penetration of the existing radio applications
regulatory
technological
introduction of new radio applications
economic considerations
The requirement for global compatibility amongst many radio systems within a congested radio spectrum

5. Need for spectrum sharing
There are no more “empty” spectrum
Proposed new systems have to find way of “sharing” with some of existing systems
Thus the need for spectrum engineering and optimisation:
to find which existing radio systems are easiest to share with, and then
determine the “sharing rules”
Jukka Rakkolainen/ERO

6. Sharing methods Spacing radio systems in frequency
Using the gaps between existing channels
Spacing geographically
Using the gaps between intended deployment areas (e.g. cities vs. rural areas)
Time sharing
Exploiting different work time (day vs. night)
Working at different power levels
E.g. “underlay” spectrum use by UWB
Jukka Rakkolainen/ERO

7. Sharing implementation
Agile (cognitive) radio systems require minimum sharing rules as they could be adapting dynamically
Simple example: finding free channel in a given geographic area
Traditional rigid-design radio system will require precisely defined sharing rules
Maximum transmit power, guard-bands to existing systems, etc
Jukka Rakkolainen/ERO

8. 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
That is where SEAMCAT comes into picture!
Jukka Rakkolainen/ERO

9. The MCL approach 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 sharing rules might be unnecessarily stringent – spectrum use not optimal!
Jukka Rakkolainen/ERO

10. Monte-Carlo approach
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 accounted, the resulting rules will be more “fair” – spectrum use optimal!
Jukka Rakkolainen/ERO

11. Monte-Carlo Assumption
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
Number of trials has to be sufficiently high (many 1000s) for statistical reliability:
Not a problem with modern computers
Jukka Rakkolainen/ERO

12. Part 2: SEAMCAT-3 Software tool

13. Jukka Rakkolainen/ERO

14. History
Developed in CEPT as a co-operation between National Regulatory Administrations, ERO, industry
First released in Jan-2000, then gradually developed in several phases
Freely downloadable from ERO website (
Jukka Rakkolainen/ERO

15. Purpose SEAMCAT is designed for:
Generic co-existence studies between different radiocommunications systems operating in same or adjacent frequency bands
Evaluation of transmitter and receiver masks
Evaluation of various limits:
unwanted emissions (spurious and out-of-band),
blocking/selectivity, etc.
Not designed for system planning purposes
Jukka Rakkolainen/ERO

16. SEAMCAT tool
Used for analysis of a variety of radio compatibility scenarios:
quantification of probability of interference between various radio systems
consideration of spatial and temporal distributions of the received signals
Can model any type of radio systems in terrestrial interference scenarios
Based on Monte-Carlo generation
Jukka Rakkolainen/ERO

17. Typical examples of modelled system
Mobile:
Land Mobile Systems
Short Range Devices
Earth based components of satellite systems
Broadcasting:
terrestrial systems
DTH receivers of satellite systems
Fixed:
Point-to-Point and Point-to-Multipoint
Jukka Rakkolainen/ERO

18. Installing SEAMCAT On-line Webstart: (Windows, Linux etc...) Off-line
Internet connection is needed at least for the installation; during later runs Internet used (if available) to check for updated version
(Windows, Linux etc...)
Off-line
(Windows only)
No special processor/memory needs
Java RTE should be installed on your PC, at least version 1.6 required
Jukka Rakkolainen/ERO

19. Software architecture
Technical Library
Workspace (.sws)
Results
XML File
Event Generation Engine
EGE Display
CDMA Engine
Interference Calculation Engine
CDMA Display
Display
User Interface
Plug-ins
Reports
XML stylesheets
Future Calculation Engine
ICE Display
Jukka Rakkolainen/ERO

20. Main interface Windows-oriented Data exchange via XML files
Main element – workspace:
Simulations input data – scenario:
equipment parameters, placement, propagations settings, etc. etc.
Simulation controls: number of events etc
Simulation results: signal vectors, Pinterference
Physically - an XML file with “sws” extension
Jukka Rakkolainen/ERO

21. SEAMCAT-3 software Conceived in early 2003
Conceptually the same interface structure as in SEAMCAT-2: workspace based, dialogue views
Main reason: need to model CDMA
Also: improvement of user interfacing and general use convenience
Implemented in Java
Source code available upon request
Jukka Rakkolainen/ERO

22. Graphic interface
Shows positions of generated transceivers in victim and interfering systems;
Overview of results (dRSS, iRSS)
Intuitive check of simulation scenario;
Detailed insight into simulated data for modelled CDMA system (last snapshot only);
Jukka Rakkolainen/ERO

23. Extra features
Propagation model plug-in API(Application Programing Interface)
Post processing plug-in API
Batch simulation format (Automation of repetitive compatibility studies to be run at once)
Remote computing (Public use of a powerful server at ERO and possibility to set-up local SEAMCAT server)
Custom simulation report (XSLT->XML style sheet)
Jukka Rakkolainen/ERO

24. Plug-in
A plug-in is a (little) software programme, which may be developed by the user
Written using standard Java language, compiled using open development tools
The pre-compiled code may be then “plugged-in” at certain “insertion points” of SEAMCAT simulation flow to produce the desired “user-defined” functionality
No perceivable impact on simulation speed
Jukka Rakkolainen/ERO

25. Propagation model plug-in
This plug-in may be used to define ANY kind of propagation model, no complexity limit
The plug-in may be inserted at any point where propagation model is defined in the scenario:
Victim link
Interfering link
Interference path
CDMA/OFDMA modules
Jukka Rakkolainen/ERO

26. Post-processing plug-in
This plug-in is invoked at the end of the snapshot generation and may be used e.g.:
Powerful API
Introduce user-defined consistency checks
Model some special system design features, e.g. Smart Antennas, etc.
Account for any additional environment features, e.g. terrain/clutter impact, etc
To save intermediate results into external files for signal processing in other tools (Matlab, etc)
not applicable to CDMA (victim)
Jukka Rakkolainen/ERO

27. Remote computing To ease carrying out lengthy simulations
Jukka Rakkolainen/ERO

28. Batch simulation
“Batch” function allows automation of repetitive compatibility studies by scheduling several SEAMCAT simulations to be done in one run of the programme
Typical case – to study the impact of change of any one (or few) scenario parameters on the probability of interference
Since version 3, any parameter (and any number of them) could be varied in batch
Jukka Rakkolainen/ERO

29. Part 3: Principles of modelling various systems
”Traditional” system
CDMA system
Jukka Rakkolainen/ERO

30. Main elements of SEAMCAT scenario
Start
While i=1,N
Generate position data of Wt, Vr
Calculate dRSSi
dRSS vector
Generate position data of Itj, Wrj
Calculate iRSSi,j
iRSS vector
While j=1,M
Calculate iRSSiSUM
dRSS, iRSS to ICE A B C D
iRSS
dRSS
Interfering
Transmitter
(It)
Victim
Receiver
(Vr)
Interfering link
Victim link
Wanted
Transmitter
(Wt)
Wanted
Receiver
(Wr)
Jukka Rakkolainen/ERO

31. Creating simulations scenario
User defines a scenario, describing mutual positioning of two systems in geographical domain…
…as well as many other parameters
Jukka Rakkolainen/ERO

32. Scenario parameters Positioning of two systems in frequency Powers
Masks
Activity
Etc.
Jukka Rakkolainen/ERO

33. Event generation Random generation of transceivers Link budget
Signal values
Jukka Rakkolainen/ERO

34. How event generation works*
Succession of snapshots…
dRSS WT
1) Calculate d, Ptx, GaTx, GaRx, L IT
Snapshot#
2) Calculate dRSSi WT
iRSS VR VR
2) Calculate iRSSi
Snapshot#
1) Calculate d, Ptx, GaTx, GaRx, L
1) Calculate d, Ptx, GaTx, GaRx, L IT
2) Calculate received signal, if PC, adjust Ptx WR WR
(*) Except CDMA/OFDMA systems
Jukka Rakkolainen/ERO

35. Results of event generation
Vectors for useful and interfering signals:
dRSS
iRSS
Jukka Rakkolainen/ERO

36. Evaluating probability of interference
- For each random event where dRSS>sensitivity:
dRSS -> (C)
Desired signal value (dBm)
C/Itrial > C/Itarget?
Interfering signal (dBm)
Interference (dB)
iRSS -> (I)
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)dRSS>sens
Jukka Rakkolainen/ERO

37. CDMA modelling
Modelling of CDMA systems as victim, interferer, or both:
Voice traffic only;
Quasi-static time within a snapshot;
One direction at a time (uplink or downlink);
Particular CDMA standard defined by setting Link Level Data (CDMA2000-1X, W-CDMA/UMTS)
Impact of interference measured by excess outage (capacity loss due to interference)
Jukka Rakkolainen/ERO

38. CDMA procedure 1 2 3 4 Pre-simulation Simulation Results
This part of the GUI is used to assist the user when configuring the workspace.
All CDMA specific GUI elements are available as part of either VictimLink or InterferingLink configuration dialogs.
Pre-simulation 1
The simulation GUI elements are shown during the simulation and are used to provide information about what SEAMCAT is doing.
Since CDMA simulation can take much longer than non-CDMA simulations, there are special GUI parts used to provide information to the user.
Simulation 2
After a simulation these GUI parts are used to provide access to calculated results but also detailed insight into the last snapshot of the simulation.
Inspecting the last snapshot is considered a good way to validate the configuration of the simulated workspace.
Detailed information on the last snapshot 4 3
Results

39. First a succession of snapshots are run without interference, gradually loading the system to find the target non-interfered capacity per cell
Then the standard range of EGE snapshots is applied to generate the derived number of “target” users
apply interference and note the impact in terms of how many of initial users were disconnected
Generate position data of Wtj, Vrj
While j=1, L
Iterative process of power balancing in CDMA cells
Record dRSSi or other parameter, e.g. non-interfered CDMA capacity
Start
While i=1, N
Generate position data of Itk, Wrk
Calculate iRSSi,k
While k=1, M
Repeat iterative process of power balancing in victim CDMA cells, now with iRSS present as external impact
(N) records of interference impact
Record impacti of interference, e.g. loss of CDMA capacity
To further engines
CDMA as
interferer
CDMA as victim
Generate position data of Itj, Wrj C D
While j=1, M
Iterative process of power balancing in CDMA cells
Calculate iRSSi,j
Jukka Rakkolainen/ERO

40. CDMA: Power Control
Modelled CDMA cell is surrounded by two tiers of auxiliary cells, and total cluster of 19 (57 for three-sector deployment option) is considered in power control tuning
Application of Wrap-Around technique for calculation of distance to closest BS produces effect of “endless” uniform network
Jukka Rakkolainen/ERO

41. Modelled CDMA cell Jukka Rakkolainen/ERO Interferer-Victim distance
Other radio system, counter-part in interference simulation
Modelled CDMA cell
Two auto-generated tiers of auxiliary CDMA cells
Jukka Rakkolainen/ERO

42. Last snapshot displayed
Clear legend
BS antenna display
BS or MS info display
Last snapshot displayed
General system info
Cell specific info
Connected - voice active user
Active link
Inactive link
Dropped user
CDMA interferer
Jukka Rakkolainen/ERO

43. CDMA network-edge case
Instead of centre cell, takes the cell at the edge of CDMA PC cluster as a reference cell, wrap-around formulas adjusted as if no other cells are located beyond that cell
This should be useful for e.g. cross-border or similar interference scenarios
Jukka Rakkolainen/ERO

44. Setting Network edge case
Jukka Rakkolainen/ERO

45. Non-interfered capacity
CDMA results
Non-interfered capacity
(red)
Interfered capacity
(blue)
Difference
(green)
Number of connected UE
Initial capacity: Number of connected UEs before any external interference is considered.
Interfered capacity: Results after external interference is applied.
Excess outage, users: How many UEs were dropped due to external interference.
Outage percentage: Percentage of UEs dropped due to external interference.

46. CDMA results

47. Part 4: SEAMCAT information

48. On-line manual

49. CEPT SEAMCAT workspace publicly available
Existing .sws files which have been generated as part of some ECC report or CEPT reports activities can be found at

50. Reference material and workspaces

51. Conclusions
Sharing rules are important element of spectrum optimisation process
Unless some intelligent interference avoidance is implemented in radio systems, the careful choice of sharing conditions is the only means for achieving successful co-existence and optimal spectrum use
Statistical tool SEAMCAT is a powerful tool for such analysis
On-line manual
Existing CEPT SEAMCAT workspaces are publicly available
Jukka Rakkolainen/ERO

52. Thank you - Any questions?