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Modeling of Unwanted and Blocking Interference Modes. European Communications Office Jean-Philippe Kermoal 05 October 2010. Interfering Modes. Unwanted Emissions Case. Blocking Case. Interference Calculations. Interference Criteria. Interfering Modes. Unwanted and Blocking Signals.
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Modeling ofUnwanted and Blocking Interference Modes European Communications Office Jean-Philippe Kermoal 05 October 2010
Interfering Modes • Unwanted Emissions Case • Blocking Case
Interference Calculations Interference Criteria Interfering Modes Unwanted and Blocking Signals
Interferer emission mask fI Unwanted Emissions • Victim Receiver Bandwidth fv • Interfering System Interfering emission mask fI
Victim Link Frequency
Victim Link / Victim Receiver Interference Criterion Reception bandwidth
Interfering Link Frequency
Interfering Link/Interfering transmitter Power Emission Mask
Interfering Link/Interfering transmitter/Unwanted emissions mask Default value erroneous value See the following presentations...
Interfering Link/Victim receiver -> Interfering transmitter Path Att = + 32.4 + 20 x log (f (MHz)) + 20 x log (d (km)) Att = + 32.4 + 20 x log (900 MHz) + 20 x log (10 km) Att = + 111.5 dB
Simulations... 10 km IRSS Unwanted = P in the victim bandwidth + Ge + Gr – Att (free space)IRSS Unwanted = 12 dBm + 0 dB + 0 dB – 111.5 dBIRSS Unwanted = - 99.5 dBm
Results N = -110 dBmIRSS Unwanted = -99.5 dBmI/N = -99.5 – (-110) = 10.5 dB ( Calculated by SEAMCAT)Interference Criterion was: I/N = 0 ( Input to SEAMCAT)
Results... I/N=0dB Pe = 22.5 dBm
Blocking • Victim Receiver Bandwidth Rejection of the receiver fv fI • Interfering System Interferer fI
Blocking: 3 Modes User Defined (dB): Rejection at the receiverAttBlocking = BlockUD Protection Ratio (dB):AttBlocking = BlockPR + C/(N+I) + 3 dB Sensitivity Mode (dBm): Maximum Acceptable Value of PowerAttBlocking = BlockSens (dBm) – Sensitivity (dBm) + C/(N+I)
But not so different • Protection Ratio:Interfering Blocking Level = Pe + Ge + Gr – Att – AttBlockingWhere: AttBlocking = BlockPR + C/(N+I) + 3 dB • If C/(N+I) = - 3 dB AttBlocking = BlockPR - 3 dB + 3 dB = BlockPR • ....equivalent to User Defined Mode • If C/I = 0 dBBroadcast PR Mode...
fV fI Blocking Mask Should be defined at the frequency of the Interferer Att blocking = 50 dB (e.g. Defined in ETSI Standards)
Simulations IRSS Blocking= Pe + Ge + Gr – Att (free space) – Att blockIRSS Blocking= 33 dBm + 0 dB + 0 dB – 111.5 dB – 50 dBIRSS Blocking = - 128.5 dBm
Results IRSS Blocking Level = - 128.5 dBmN = -110 dBmI/N = 0 dB (Criterion) always met
Question? • Can I make simulation for unwanted and blocking in the same workspace?
Question: Can I make simulation for unwanted and blocking in the same workspace? • 2 Interference Criteria / 2 runs
Question: Can I run simulations for unwanted and blocking in the same workspace in a single run? If the interference criteria are not the same... You can compensate this when defining the mask (unwanted or blocking) Blocking: PR mode + Criterion: C/I=0 dB Unwanted: Criterion C/I=10 dB Remove 10 dB from blocking mask Criterion C/I=10 dB
Questions? • Thanks for your attention