Introduction to SEAMCAT European Communications Office Jean-Philippe Kermoal - SEAMCAT Manager (ECO) October 2010 EUROPEAN COMMUNICATIONS OFFICE Nansensgade 19 DK-1366 Copenhagen Denmark Telephone: + 45 33 89 63 00 Telefax: + 45 33 89 63 30 E-mail: ero@ero.dk Web Site: http://www.ero.dk Jukka Rakkolainen/ERO

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

Part 1: Why SEAMCAT?

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

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

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

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

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

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

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

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

Part 2: SEAMCAT-3 Software tool

Jukka Rakkolainen/ERO

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 (www.ero.dk/seamcat) Jukka Rakkolainen/ERO

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Setting Network edge case Jukka Rakkolainen/ERO

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.

CDMA results

Part 4: SEAMCAT information

On-line manual www.ero.dk/seamcat www.seamcat.org/xwiki

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 www.erodocdb.dk

Reference material and workspaces

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

Thank you - Any questions?