ATDI Consulting ATDI · PDF fileMicrowave mode interference Calculations Point to Point only...
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Transcript of ATDI Consulting ATDI · PDF fileMicrowave mode interference Calculations Point to Point only...
ATDI Consulting
ATDI Software
ATDI Commercial in Confidence ©Copyright ATDI 2006 All rights reserved.
Mobile Interference
Calculations in
ICS Telecom &
HTZ WarfareNovember 2010
ATDI Commercial in Confidence ©Copyright ATDI 2006 All rights reserved.
Introduction
• This Webinar will cover:-
– What is interference
– Types of interference calculations in
ICS Telecom & HTZ Warfare
– Mobile interference calculations
– Masks
– Interference calculations with multiple
propagation models
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Interference Calculation used in
ICS Telecom
• Carrier to Noise ratio (C/I)
• Threshold Impairment (TI)
• Interference to Noise ratio (I/N)
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What is Interference
Thermal noise floor of receiver N (kTBF)
Receiver threshold
point
RX Noise Fig.(F)
FadeMargin
Receive level (C)
Threshold Impairment
InterferenceI
C/I ratio
Minimum
C/I ratio
Carrier to Interference C/I Threshold Impairment TI Interference to Noise ratio I/N
Thermal noise floor (kTB)
I/N
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Calculating coverage for interference
calculationsTips:Make sure you predict far enough (Setting limit distance)
For Communication systems predict to noise floor or below
For Radar systems predict to at least 12dB below noise floor
Not ticked
Mechanical or electrical tilt
(not tilt and resolution from RX parameters)
Attenuation between
systems at same site
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Interference calculations within
ICS Telecom & HTZ Warfare
Coverage mode interference
calculations
MFN , SFN and Radar
Microwave mode interference
Calculations Point to Point only
Multi point mode interference
Calculations Point to Point only
stations, microwave & subscribers
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W-CDMA mode interference
Pilot Ec/Io and traffic & Eb/No
Subscriber interference
Calculations Point to Multi Point
and Multipoint to point only
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Both these interference calculations
are based on virtual TXs or RXs
into fixed TXs or RXs
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This will modify C
C= C+10LOG(activity)
STD
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Masks
Image Raster
Data Raster
DEMONSTRATION
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NFD• IRF Calc
Spectral Mask
Receiver Selectivity
Set up all directories
DEMONSTRATION
Priority 1
Show ATDI/BASE
Directory
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Priority 2
Predefined Masks
FM Broadcast
e.g.TV Broadcast
Analogue & Digital
802.11
802.16
Some Microwave
systems
etc
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Frequency
F1
B1
B2
-44dBm
-79dBm
-97 dBm Receiver Noise Floor (kTBF)
FrequencyN=0
0dB
Interference Rejection Factor
F2
20dB
40dB
N=1 N=2N=-1
-75dBm
F3
F2’
RX1
Wanted F1 Rx signal =-44dBm
Un Wanted F2 Rx signal =-79dBm
Un Wanted F2’ Rx signal =-75dBm
Un Wanted F3 Rx signal =-80dBm
-80dBm
C/I =-44 - (10^(-79/10+10LOG0.2)+
10^(-79-20/10) +10^(-75-20/10)+10^(-80-40/10)))
Overlap area, % of B1 overlapped eg. 20%
Overlap area
of F2
F2 F2’F3
Multiple Interference signals
Wanted
N=0 co-channel with Receiver
N=1 adjacent channel with receiver
Etc.
Priority 3
Assumes response curve symmetrical
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Best method of checking what
interference calculations do• Produce DTM & Clutter map suitable
for checking interference calculations
on (flat earth & no clutter)
Select suitable propagation model
(free space path loss)
DEMONSTRATIONCheck what's going on with Analysis function
“A”
Change elevation code
Change clutter code
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Interference Calculations
Defines C/I required
Global Interference – Pixel interfered if at least one serving site is deemed interfered
Interference+best server – Pixel interfered as global unless service available from
another site or channel
Interference on best server – Pixel interfered when C/I required on best server is
exceeded
Interference Activated + De –act. Pixel interfered if interference is deemed present
when active sites are interfered with by all other active and deactivated sites
Interference Network ID – Interference between sites with same Network ID is
excluded
Interference wanted signals- Displays the number of channels available (with no
interference)
C/I Map: Min(C/I) – C/I map assuming C is at Global threshold level (activated sites
only)
C/I map on best server – shows maximum interference to receivers connected to best
server activated stations only – multichannel
Protection margin – shows the C/I protection above wanted C/I based on best server
Protected field strength – shows the unwanted field strength in the wanted service area
where field strength is modified by required protection ratio (C/I)
Demonstration
Coverage /Network Interference/ C/I Mode
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Coverage /Network Interference/ IRF Mode
Threshold Degradation – calculates the
degradation of the noise floor (Global or
RX specific)
Modifies coverage by TD of power
sum of all activated and un-activated stations
Based on each stations KTBF
C/I Calcs
Demonstration
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Interference calculations using
multiple propagation models
DEMONSTRATION
•Export unwanted coverage: File / Export / Export TX
coverage to FDU files
•Load wanted coverage
•Undertake interference calculation(s)
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Thank you for attending
This webinar covered most of the basic
interference calculations for mobile systems
within ICS Telecom and HTZ Warfare
Any Questions?
ATDI Limited
Kingsland Court - Three Bridges Road
Crawley - West Sussex - RH10 1HL – UK
Tel +44 (0)1293 522052 - Fax +44 (0)1293 522521
Email: [email protected]
Web: www.atdi.co.uk www.atdi.de www.atdi.no