Introduction to SEAMCAT European Communications Office Jean-Philippe Kermoal - SEAMCAT Manager (ECO)...

Introduction to SEAMCATIntroduction to SEAMCAT

European Communications OfficeJean-Philippe Kermoal - SEAMCAT Manager (ECO)

October 2010

EUROPEANCOMMUNICATIONSOFFICE

Nansensgade 19DK-1366 CopenhagenDenmark

Telephone: + 45 33 89 63 00Telefax: + 45 33 89 63 30

E-mail: [email protected] Site: http://www.ero.dk

SEAMCAT WorkshopJean-Philippe Kermoal / ECO

05 October 2010

OutlineOutline

• 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


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Part 1: Part 1: Why SEAMCAT?Why SEAMCAT?


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Spectrum engineering Spectrum engineering challengeschallenges

The requirement for global compatibility amongst many radio systems within a congested radio spectrum

introduction of new radio applications

technological

regulatory

economic considerations

increasing penetration of the existing radio applications


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• 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”

Need for spectrum sharingNeed for spectrum sharing


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• 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

Sharing methodsSharing methods


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• 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

Sharing implementationSharing implementation


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• 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!

Defining the sharing rulesDefining the sharing rules


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• 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!

The MCL approachThe MCL approach


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• Repeated random generation of interferers and their parameters (activity, power, etc…)

– After many trials, not only unfavourable, but also favourable cases will be accounted, the resulting rules will be more “fair” – spectrum use optimal!

Wanted Signal

InactiveInterferer

Victim

ActiveInterferer

t=t0

t=t1t=ti

Monte-Carlo approachMonte-Carlo approach


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• 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

Monte-Carlo AssumptionMonte-Carlo Assumption


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Part 2: Part 2: SEAMCAT-3 Software toolSEAMCAT-3 Software tool


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HistoryHistory

• 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 (www.ero.dk/seamcat)


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• 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

PurposePurpose


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SEAMCAT toolSEAMCAT 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


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• 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

Typical examples of Typical examples of modelled systemmodelled system


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Installing SEAMCATInstalling SEAMCAT

On-line Webstart: Internet connection is needed at least for the installation; during later runs Internet used (if available) to check for updated version

Off-line

(Windows, Linux etc...)

(Windows only)

• No special processor/memory needs• Java RTE should be installed on your PC, at least version 1.6 required


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Software architectureSoftware architecture

Technical Library Workspace (.sws)

ResultsXML File

Event Generation Engine EGE Display

CDMA Engine

Interference Calculation Engine

CDMA Display

Display

User InterfacePlug-ins

ReportsXML stylesheets

Future Calculation Engine

ICE Display


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• 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

Main interfaceMain interface


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SEAMCAT-3 softwareSEAMCAT-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


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Graphic interfaceGraphic 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);


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Extra featuresExtra 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)


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• 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

Plug-in Plug-in


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• 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

Propagation Propagation model plug-inmodel plug-in


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• 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)

Post-processing plug-inPost-processing plug-in


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• To ease carrying out lengthy simulations

Remote computingRemote computing


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• “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

Batch simulationBatch simulation


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Part 3:Part 3:Principles of modelling various Principles of modelling various systemssystems

- ”Traditional” system- CDMA system


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Main elements of Main elements of SEAMCAT scenarioSEAMCAT scenario Start

While i=1,N

Generate position data of Wt, Vr

Calculate dRSSi

dRSS vector

While i=1,N

Generate position data of It j, Wrj

Calculate iRSSi,j

iRSS vector

While j=1,M

Calculate iRSSiSUM

dRSS, iRSS to ICE

A

B

C

D

Wanted Transmitter

(Wt)

Victim Receiver

(Vr)

Wanted Receiver

(Wr)

Interfering Transmitter

(It)

dRSS

iRSS

Victim link

Interfering link


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Creating simulations Creating simulations scenarioscenario

• User defines a scenario, describing mutual positioning of two systems in geographical domain…

5 km MS-Iti

Wr BS-Vr

Wti

…as well as many other parameters


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• Positioning of two systems in frequency• Powers• Masks• Activity• Etc.

Scenario parametersScenario parameters


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• Random generation of transceivers• Link budget• Signal values

Event generationEvent generation


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• Succession of snapshots…

VR

WT

1) Calculate d, Ptx, GaTx, GaRx, L

2) Calculate dRSSi

dRSS

Snapshot#iRSS

Snapshot#

IT

WR


2) Calculate received signal, if PC, adjust Ptx


2) Calculate iRSSi VR

WT

IT

WR

How event generation How event generation works*works*

(*) Except CDMA/OFDMA systems


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• Vectors for useful and interfering signals:

Results of event Results of event generationgeneration

dRSS

iRSS


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Evaluating probability Evaluating probability of interferenceof interference

- For each random event where dRSS>sensitivity:

Noise Floor (dBm)

Desired signal value (dBm)

Interfering signal (dBm) C/Itrial > C/Itarget?

Interference (dB)

- 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

dRSS -> (C)

iRSS -> (I)


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CDMA modellingCDMA 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)


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CDMA procedureCDMA procedure

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-simulation1

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.

Simulation2

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 snapshot4

3 Results


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• 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 victim

Generate position data of It j, Wrj

C

D

While j=1, M

Iterative process of power balancing in CDMA cells

Calculate iRSSi,j

While j=1, M

CDMA as interferer


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CDMA: Power ControlCDMA: 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


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Modelled CDMA cellModelled CDMA cell

Modelled CDMA cell

Two auto-generated tiers of auxiliary CDMA cells

Other radio system, counter-

part in interference simulation

Interferer-Victim distance


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Last snapshot displayed

BS or MS info display

BS antenna display

General system infoCell specific infoConnected - voice active userActive linkInactive linkDropped userCDMA interferer

Clear legend


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CDMA network-edge caseCDMA 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


05 October 2010

Setting Network edge caseSetting Network edge case


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CDMA resultsCDMA results

• 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.

Number of connected UE

Interfered capacity(blue)

Non-interfered capacity(red)

Difference(green)


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CDMA resultsCDMA results


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Part 4:Part 4:SEAMCAT informationSEAMCAT information


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On-line manualOn-line manual

www.ero.dk/seamcat

www.seamcat.org/xwiki


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CEPT SEAMCAT workspace CEPT SEAMCAT workspace publicly availablepublicly available

• Existing .sws files which have been generated as part of some ECC report or CEPT reports activities can be found at www.erodocdb.dk


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Reference material and Reference material and workspacesworkspaces


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ConclusionsConclusions

• 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


05 October 2010

Thank you - Any questions?Thank you - Any questions?

Introduction to SEAMCAT European Communications Office Jean-Philippe Kermoal - SEAMCAT Manager (ECO)...

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