Source: Karl Löw, T-Nova, Deutsche Telekom
Date: ERO, Copenhagen, 7-June-2001
SEAMCAT Training (phase 1)
Practical example
Scenario: Tetra MS interferes the BS of the
analogue FM PMR
1. Description
of the radio compatibility problem
This document provides an analysis of
TETRA MS interfering with an FM BS, based on the information retained in the
ERC Report 104 on “Adjacent Band Compatibility Of 400MHz TETRA And Analogue FM
PMR – An Analysis Completing Using MONTE CARLO Based Simulation Tool”. This
scenario involves a population of TETRA mobile stations interfering with a
victim FM base station. In all of the simulations the victim FM system is
assumed to have a 7.8 km cell radius which provides a 90 % area availability.
Figure 1 : Victim link /
Interfering link
Figure 2
illustrates the band plan assumed for this investigation. 2 MHz of spectrum has
been allocated to the up-link of TETRA and directly adjacent to this, 2 MHz has
been allocated to FM.
Figure 2 : band allocations of TETRA MS
and FM BS systems
The purpose of this example is to use SEAMCAT to
obtained the probability of interference resulting from unwanted emissions of
the TETRA Mobile Stations falling at the frequency where the FS Based Station
is operating.
2 Characteristics
of the systems
2.1 Victim
link characteristics – FM
The victim FM system is assumed to have a 7.8 km cell radius which provides a 90 % area
availability. The reception bandwidth of FM BS victim receiver is equal to 8kHz.
Based on information provided in ERC Report 104 for FM system based on 12.5kHz
channel spacing, the following characteristics are used to describe the FM
equipments:
|
Parameter
|
Mobile
Station
|
Base
Station
|
|
Channel Spacing
|
12.5 kHz
|
12.5 kHz
|
|
Transmit Power
|
37 dBm
|
44 dBm
|
|
Receiver Bandwidth
|
8 kHz
|
8 kHz
|
|
Antenna Height
|
1.5 m
|
30 m
|
|
Antenna Gain
|
0 dBi
|
9 dBi
|
|
Active Interferer Density Range
|
Variable
|
variable
|
Receiver
Sensitivity
|
- 107 dBm
|
- 110 dBm
|
|
Receiver Protection Ratio
|
21 dB
|
21 dB
|
|
Power Control Characteristic
|
Not used
|
not used
|
Table 1 : Parameters Assumed
for 12.5 kHz FM Systems
The Noise Floor is obtained by using the
following equation (see revised ERC Report 68):
Noise Floor = Sensitivity – Receiver Protection Ratio
|
Frequency Offset
|
Base Station
|
|
Any frequency
|
- 23 dBm
|
Table 2 :
Receiver Blocking for 12.5 kHz FM Systems
2.2 Interfering
link characteristics – TETRA
The interfering
TETRA system is assumed to have a 18kHz emission bandwidth and a channel
spacing which is equal to 25kHz. The distribution in term of frequency use over
the 2MHz band, is taken as a uniform distribution, where each channel being
assigned the same probability. Based on information provided in ERC Report 104
for TETRA system based on 25kHz channel spacing, the following characteristics
are used to describe the TETRA equipments:
|
Parameter
|
Mobile Station
|
Base
Station
|
|
Channel Spacing
|
25 kHz
|
25 kHz
|
|
Transmit Power
|
30 dBm
|
40 dBm
|
|
Receiver Bandwidth
|
18 kHz
|
18 kHz
|
|
Antenna Height
|
1.5 m
|
30 m
|
|
Parameter
|
Mobile Station
|
Base Station
|
|
Antenna Gain
|
0 dBi
|
9 dBi
|
|
Active Interferer Density Range
|
Variable
|
Variable
|
|
Receiver Sensitivity
|
- 103 dBm
|
- 106 dBm
|
|
Receiver Protection Ratio
|
19 dB
|
19 dB
|
|
Power Control Characteristic
|
|
|
Table 3 : Parameters used to
model the TETRA Systems (interfering transmitter)
|
Frequency Offset
|
30 dBm Mobile Station
|
Attenuation in dBc
|
|
25 kHz
|
- 30 dBm
|
60
|
|
50 kHz
|
- 36 dBm
|
66
|
|
75 kHz
|
- 36 dBm
|
66
|
|
100 - 250 kHz
|
- 45 dBm
|
75
|
|
250 - 500 kHz
|
- 50 dBm
|
80
|
|
> 500 kHz
|
- 70 dBm
|
100
|
Table 4 : Unwanted Emissions
for the TETRA Systems (measurement bandwidth of 18 kHz) (interfering
transmitter)
3 Assumptions
to be conducted during the training session
Starting from
the characteristics provided above, some “reference” hypothesis may be used to
obtain a first set of results.
3.1 TETRA
network
A 2 MHz band
is available for TETRA systems of 25 kHz channel spacing, then a total of 80
channels are available. It is supposed that only one TETRA MS terminals may use
the same frequency at a given time.
The frequency cluster is taken equal to 9, this leads to have
80/9=8.88 frequency per cell available. Then up to 9 terminals may be deployed
in a TETRA cell.
If the TETRA cell is the traffic limited network and the density of
terminals equal to 5 terminals/km², then the coverage radius is given by
the following formula (see ERC Report 68 or User Documentation):
The radius
of the cell of the interfering system is given by
R=sqrt((80*1)/(3.14*5*9))=0.7523 km.
The following picture describes a TETRA
network based on the above assumptions.
Figure
3 : TETRA network based on these assumptions
3.2 Interference
situation
As a worst case assumption, we may suppose that,
the FM BS station will be based in the TETRA cell where the channel
(411.9875MHz) operating close to the edge of the TETRA band is used. The same
probability is assigned to each channel available in
the TETRA cell. Then the frequency plan in
this cell starts from 410.1874MHz up to 411.9875MHz with a step of 25kHz*9. The
frequency distribution is depicted in the following figure.
Figure
4 : frequency distribution in the TETRA
cell
For simplification a uniform distribution of the
frequency between 410.1875 and 411.9875 MHz is assumed.
If there is no spatial correlation between the
elements of the victim system and the elements of the interfering system then
the simulation radius is given by the formula:
=
radius
of the area where interferers are spread
We have to
consider 9 active interferers with a density of 5 terminals/km²: Then, the
radius of the simulation area results in
R=sqrt(9/(3.14*5))=0.7569km.
The FM Based Station, which is the victim
receiver is supposed to be operating at 412.00625MHz, that is the center of the
first channel, i.e. no guard interval is assumed.
3.3 Unwanted
emission mask
The total emission of the interfering
transmitter consists of
·
the wanted signal within the defined bandwidth
corresponding to an frequency offset of ± 50 % of the necessary bandwidth Bn,
·
the out-of-band emission caused by the
modulation within, e.g. ± 50...250 % of Bn
·
and the spurious emission outside these ranges.
That means the mask to be defined has to
cover this whole range. It is strongly recommended to define always such an
"unwanted mask" rather to use the constant option which will be
blocked in the upgraded version anyway.
It should be noted that the TETRA MS
unwanted emissions mask is not defined for frequency offset below 25 kHz.
Considering the channel spacing of 25 kHz and assuming 0 dBc in that range,
then in the undefined range between 12.5 and 25 kHz, a linear interpolation
between 0 and 60 dBc attenuation will be taken place. It should also taken into
account that the reference bandwidth (18 kHz) used for the mask is identical to
the bandwidth of the interfering system!
4 Probability
of interference
Based on the above assumptions the
probability of interference (C/I criteria and unwanted emissions + blocking are
taken into account) is about 2.5 %.
Step-by-step implementation
·
Definition of the work space, name:
"TETRA-PMR"
1. Victim link
·
Reference: PMR
·
Frequency: 412.00625
MHz (channel
spacing)
·
Use wanted transmitter:
yes
1.1 Victim
Receiver
·
Reference: PMR-BS
·
C/I: 21
dB (if
only C/I, C/(N+I) and (I+N)/N are not required)
·
C/(I+N) 21
dB (C/(N+I)
required only for selected Blocking-Mode)
·
(N+I)/N 0 (not
required)
·
Noise floor: -131
dBm, constant (=Sensitivity
– C/I)
·
Blocking response: -23
dB, constant
·
Blocking mode: Sensitivity
·
Sensitivity: -110
dBm
·
Bandwidth receiver: 8
kHz
·
Antenna height: 30
m, constant
·
Antenna azimuth: 0...360
Grad, uniform
·
Antenna elevation: 0
Grad, constant (horizontal
direction)
1.1.1 Antenna
·
Reference: PMR-BS
·
Description: Omnidirectional
·
Maximum gain: 9
dBi
1.2 Wanted
Transmitter
·
Reference: PMR-MS
·
Power: 37
dBm, constant
·
Antenna height: 1.5
m, constant
·
Antenna azimuth: 0...360
Grad, uniform
·
Antenna elevation: 0
Grad, constant (horizontal
direction)
1.2.1 Antenna
·
Reference: PMR-MS
·
Description: Omnidirectional
·
Maximum gain: 0
dBi
1.3 WTx-VRx
path
·
Computation of the cell
radius: User-defined radius
·
Fixed radius: 7.8
km
·
Correlation: No (for
WT-VR)
·
Radio path length: uniform
polar (Distance
VR: (0...1)*cell radius)
·
Path Azimuth VR: 0...360
Grad, uniform
1.3.1 Propagation
model
·
Model: Hata
·
Median Loss: Yes
·
Variation: Yes
·
Environment: RURAL (results
in lowest path attenuation)
·
...at WT: OUTDOOR
·
...at VR: OUTDOOR
·
Propagation: ABOVE
ROOF (caused by 30m
BS-Antenna height)
2. Interfering link 1
·
Reference: TETRA-PMR-ILK1
·
Frequency: 410.1875...411.9875
MHz, uniform
2.1 Interfering
Transmitter
·
Reference: TETRA-MS
·
Transmitting power: 30
dBm, constant
·
Unwanted mask: Offset
in MHz, power in dBc referred to Reference bandwidth
·
Unwanted emission
floor: NO
·
Transmitting bandwidth: 18
kHz (Bandwidth
< channel)
·
Reference bandwidth: 18
kHz
·
Power Control: YES
·
PC-Step: 5
dB
·
Minimal received power: -86
dBm
·
Maximum received power: -71
dBm
·
Antenna height: 1.5
m, constant
·
Antenna azimuth: 0...360
Grad, uniform
· Antenna elevation: 0
Grad, constant (horizontal
direction)
2.1.1 Antenna
·
Reference: TETRA-MS
·
Description: Omnidirectional
·
Maximum gain: 0
dBi
2.2 Wanted
Receiver (only
for power control)
·
Reference: TETRA-BS
·
Antenna height: 30
m, constant
·
Antenna azimuth: 0...360
Grad, uniform
·
Antenna elevation: 0
Grad, constant (horizontal
direction)
2.2.1 Antenna
·
Reference: TETRA-BS
·
Description: Omnidirectional
·
Maximum gain: 9
dBi
2.3 ITx-VRx
path
Computation of the simulation radius
·
Active interferers: 9 (see
1.3.2.)
·
Density of active
interferers: 5 users/km² (see
1.3.2)
·
Probability of
transmission: 1 (transmits
permanently)
·
Activity per hour: 1 (transmits
permanently)
·
Correlation: None (for
IT-VR or IT-WT)
·
Radio path length: uniform
polar (Distance:
(0...1)*simulation radius)
·
Path Azimuth: 0...360
Grad, uniform
2.3.1 Propagation
model
see 2.1.3.1
2.4 ITx-WRx
path
Computation of the radio coverage of the interferer
·
Mode: Traffic-limited
network
·
Density of interferers: 5
users/km² (see
1.3.2)
·
Number of channels: 80 (see
1.3.2)
·
User per channel: 1 (see
1.3.2)
·
Frequency cluster: 9 (see
1.3.2)
·
Correlation: No (for
IT-WR)
·
Radio path length: uniform
polar (Distance:
(0...1)*cell radius)
·
Path Azimuth: 0...360
Grad, uniform
2.4.1 Propagation
model
see 2.1.3.1
3. Simulation control
3.1 Event
generation
·
Number of samples: 2000 (Default:
20000)
·
Stop of simulation: Number
of events
3.2 Distribution
evaluation
This evaluation is used to test the
distribution to Gaussian and/or to stop the calculation, if a sufficient
reliability of the results are given in the case of DEE-Mode.
3.3 Test
of the simulation
3.3.1 Calculated
radius
·
Cell radius of the
wanted system: 7.8 km
·
..interfering system 1: 0.752
km
·
..simulation radius 1: 0.7569
km
3.3.2 Generated
Signals
·
dRSS: mean: -69.6
dBm standard deviation: 11.9 dB Gaussian
·
iRSS unwanted: mean: -125.7
dBm standard deviation: 11.9 dB
·
iRSS blocking: mean: -144.5
dBm standard deviation: 7.4 dB
3.3.3 Correlation,
Exceptions
4 Interference calculation
4.1 ICE
calculation
·
Algorithms: Quick
·
Number of samples: 2000 (£ number in 2.3.1)
·
Compatibility mode: 0 (Probability
of interference)
·
Unwanted emissions: Yes
·
Blocking" Yes
4.2 Result
·
Probability: 0.0250
(=
2.5 %)
SEAMCAT SIMULATION REPORT
SEAMCAT SIMULATION REPORT
Reference
: TETRA-PMR
Simulation
scenario
Victim
Link
Reference
: PMR
Description
:
Frequency
: 412.00625 MHz
Use
wanted transmitter : Yes
Victim
Receiver
Reference
: PMR-BS
Description
:
C
/ I : 21 dB
C
/ (N+I) : 21 dB
(N+I)
/ N : 0 dB
Noise floor distribution : Constant(-131.0)
Blocking response : Constant(-23.0000)
Blocking
attenuation mode : Sensitivity
Sensitivity
: -110 dBm
Reception
bandwidth : 8 kHz
Intermodulation rejection : Constant(0.0000)
Use power control threshold : No
Antenna
height distribution : Constant(30.0)
Antenna
azimuth distribution : Uniform(0.0,360.0)
Antenna
tilt distribution : Constant(0.0)
Antenna
Reference
: PMR-BS
Description
: Omnidirectional
Peak
gain : 9 dBi
Use
horizontal pattern : No
Use
vertical pattern : No
Wanted
Transmitter
Reference
: PMR-MS
Description
:
Power
supplied distribution : Constant(37.0)
Antenna
height distribution : Constant(1.5)
Antenna
azimuth distribution : Uniform(0.0,360.0)
Antenna
tilt distribution : Constant(0.0)
Coverage
radius parameters
Coverage
radius calculation mode : User-defined radius
Fixed
coverage radius : 7.8 Km
Antenna
Reference
: PMR-MS
Description
: Omnidirectional
Peak
gain : 0 dBi
Use
horizontal pattern : No
Use
vertical pattern : No
WTx
VRx path
Relative
location
Correlated
: No
Path
distance factor distribution : Uniform polar distance(1.0)
Path
azimuth distribution : Uniform(0.0,360.0)
Propagation
model
Model
reference : Hata
Median
loss : Yes
Variations
: Yes
General
environment : RURAL
Transmitter
environment : OUTDOOR
Receiver
environment : OUTDOOR
Propagation
environment : ABOVE ROOF
Floor
loss : 18.3 dB
Empirical
parameter B : 0.46
Room
size : 4 m
Floor
height : 3 m
Wall
loss (indoor-indoor) : 5 dB
Wall
loss (indoor-outdoor) : 10 dB
Wall
loss std. dev. (indoor-indoor) : 10 dB
Wall
loss std. dev. (indoor-outdoor) : 5 dB
Interfering
Link 1
Reference
: TETRA-PMR_ILK1
Description
:
Frequency
distribution : Uniform(410.2,412.0)
Interfering
Transmitter
Reference
: TETRA-MS
Description
:
Power
supplied distribution : Constant(30.0)
Unwanted
emissions : Array(20)
-10.0000 -100.0000
-0.5010 -100.0000
-0.5000 -80.0000
-0.2510 -80.0000
-0.2500 -75.0000
-0.1000 -75.0000
-0.0750 -66.0000
-0.0500 -66.0000
-0.0250 -60.0000
-0.0125 0.0000
0.0125 0.0000
0.0250 -60.0000
0.0500 -66.0000
0.0750 -66.0000
0.1000 -75.0000
0.2500 -75.0000
0.2510 -80.0000
0.5000 -80.0000
0.5010 -100.0000
10.0000 -100.0000
Use
unwanted emission floor : No
Emission bandwidth : 18 kHz
Reference
bandwidth : 18 kHz
Use power control : Yes
Antenna
height distribution : Constant(1.5)
Antenna
azimuth distribution : Uniform(0.0,360.0)
Antenna
tilt distribution : Constant(0.0)
Power
control parameters
Power
control step : 5 dB
Min
received power : -86 dBm
Max
received power : -71 dBm
Coverage
radius parameters
Coverage
radius calculation mode : Traffic-limited network
Users
density : 5 users/Km²
Number
of channels : 80
Number
of users per channel : 1 users/ch
Frequency
re-use : 9
Simulation
radius parameters
Number
of active transmitters : 9
Density
of active transmitters : 5 1/Km²
Transmission
probability : 1
Activity
: Constant(1.0000)
Time
: 5 hour
Antenna
Reference
: TETRA-MS
Description
:
Antenna
peak gain : 0 dBi
Use
Horizontal pattern : No
Use
vertical pattern : No
Wanted
Receiver
Reference
: TETRA-BS
Description
:
Antenna
height distribution : Constant(30.0)
Antenna
azimuth distribution : Uniform(0.0,360.0)
Antenna
tilt distribution : Constant(0.0)
Antenna
Reference
: DEFAULT_ANT
Description
:
Peak
gain : 9 dBi
Use
horizontal pattern : No
Use
vertical pattern : No
ITx VRx path
Relative
location
Correlation
mode : None
Path distance factor distribution : Uniform polar distance(1.0)
Path
azimuth distribution : Uniform(0.0,360.0)
Propagation
model
Model
reference : Hata
Median
loss : Yes
Variations
: Yes
General
environment : RURAL
Transmitter
environment : OUTDOOR
Receiver
environment : OUTDOOR
Propagation
environment : ABOVE ROOF
Floor
loss : 18.3 dB
Empirical
parameter B : 0.46
Room
size : 4 m
Floor
height : 3 m
Wall
loss (indoor-indoor) : 5 dB
Wall
loss (indoor-outdoor) : 10 dB
Wall
loss std. dev. (indoor-indoor) : 10 dB
Wall
loss std. dev. (indoor-outdoor) : 5 dB
ITx
WRx path
Relative
location
Correlated
: No
Path
distance factor distribution : Uniform polar distance(1.0)
Path
angle distribution : Uniform(0.0,360.0)
Propagation
model
Model
reference : Hata
Median
loss : Yes
Variations
: Yes
General
environment : RURAL
Transmitter
environment : OUTDOOR
Receiver
environment : OUTDOOR
Propagation
environment : ABOVE ROOF
Floor
loss : 18.3 dB
Empirical
parameter B : 0.46
Room
size : 4 m
Floor
height : 3 m
Wall
loss (indoor-indoor) : 5 dB
Wall
loss (indoor-outdoor) : 10 dB
Wall
loss std. dev. (indoor-indoor) : 10 dB
Wall
loss std. dev. (indoor-outdoor) : 5 dB
Simulation
control
Event
generation
EGE
Number of events : 2000
EGE
Expected duration : 1 min
EGE
Termination condition : Number of events
Distribution
evaluation
DEE
incremental number of events : 2000
DEE
stability threshold : 0.8
DEE
identification threshold : 0.2
DEE
correlation threshold : 0.8
Results
Calculated
radius
Wanted
transmitter coverage radius : 7.8 Km
Interfering
transmitter coverage radius 1 : 0.75225277806365 Km
Interfering
transmitter simulation radius 1 : 0.756939756606023 Km
Generated
signals
dRSS
dRSS
vector : Array(2000)
Standard
deviation :11.6
Mean
:-69.8
0% -107.2
0.5% -98.3
1% -95.2
1.5% -93.5
2% -92.5
2.5% -91.4
3% -89.9
3.5% -89.4
4% -89.0
4.5% -88.4
5% -87.8
6% -86.9
7% -86.1
8% -85.0
9% -84.5
10% -83.9
15% -81.4
20% -79.5
30% -76.3
40% -73.1
50% -70.6
60% -67.6
70% -64.5
80% -61.0
85% -58.5
90% -55.2
91% -54.2
92% -53.0
93% -51.9
94% -50.7
95% -49.4
95.5% -48.8
96% -47.5
96.5% -46.4
97% -45.7
97.5% -44.8
98% -42.8
98.5% -39.7
99% -38.4
99.5% -33.2
100% -22.0
iRSS
Unwanted
iRSS
Unwanted 1 : Array(2000)
Standard
deviation :12.1
Mean
:-126.2
0% -158.9
0.5% -149.0
1% -148.1
1.5% -147.7
2% -147.0
2.5% -146.2
3% -145.8
3.5% -144.5
4% -144.2
4.5% -143.7
5% -143.1
6% -142.5
7% -141.7
8% -141.0
9% -140.4
10% -139.8
15% -137.3
20% -135.7
30% -133.1
40% -130.5
50% -127.4
60% -124.7
70% -121.5
80% -117.5
85% -114.6
90% -111.2
91% -110.6
92% -109.6
93% -108.6
94% -107.1
95% -105.6
95.5% -104.8
96% -104.1
96.5% -101.8
97% -100.6
97.5% -97.7
98% -94.9
98.5% -93.3
99% -86.2
99.5% -82.3
100% -55.8
Unwanted
Summation vector : Array(2000)
Standard
deviation :12.1
Mean
:-126.2
0% -158.9
0.5% -149.0
1% -148.1
1.5% -147.7
2% -147.0
2.5% -146.2
3% -145.8
3.5% -144.5
4% -144.2
4.5% -143.7
5% -143.1
6% -142.5
7% -141.7
8% -141.0
9% -140.4
10% -139.8
15% -137.3
20% -135.7
30% -133.1
40% -130.5
50% -127.4
60% -124.7
70% -121.5
80% -117.5
85% -114.6
90% -111.2
91% -110.6
92% -109.6
93% -108.6
94% -107.1
95% -105.6
95.5% -104.8
96% -104.1
96.5% -101.8
97% -100.6
97.5% -97.7
98% -94.9
98.5% -93.3
99% -86.2
99.5% -82.3
100% -55.8
iRSS
Blocking
iRSS
Blocking 1 : Array(2000)
Standard
deviation :7.2
Mean
:-144.4
0% -162.5
0.5% -160.2
1% -158.4
1.5% -157.7
2% -157.0
2.5% -156.5
3% -156.2
3.5% -155.9
4% -155.6
4.5% -155.5
5% -155.2
6% -154.7
7% -154.1
8% -153.6
9% -153.3
10% -153.0
15% -151.7
20% -150.5
30% -148.6
40% -146.8
50% -145.1
60% -143.3
70% -141.1
80% -138.6
85% -137.1
90% -135.0
91% -134.4
92% -133.6
93% -133.0
94% -132.6
95% -131.9
95.5% -130.9
96% -130.3
96.5% -129.6
97% -129.0
97.5% -128.3
98% -127.5
98.5% -126.1
99% -124.7
99.5% -122.4
100% -117.9
Blocking
Summation vector : Array(2000)
Standard
deviation :7.2
Mean
:-144.4
0% -162.5
0.5% -160.2
1% -158.4
1.5% -157.7
2% -157.0
2.5% -156.5
3% -156.2
3.5% -155.9
4% -155.6
4.5% -155.5
5% -155.2
6% -154.7
7% -154.1
8% -153.6
9% -153.3
10% -153.0
15% -151.7
20% -150.5
30% -148.6
40% -146.8
50% -145.1
60% -143.3
70% -141.1
80% -138.6
85% -137.1
90% -135.0
91% -134.4
92% -133.6
93% -133.0
94% -132.6
95% -131.9
95.5% -130.9
96% -130.3
96.5% -129.6
97% -129.0
97.5% -128.3
98% -127.5
98.5% -126.1
99% -124.7
99.5% -122.4
100% -117.9
iRSS
Intermodulation
Correlation
Exception
Propagation
models : 0
Pattern
: 0
Random
variables : 0
Masks
: 0
Signal
summation : 0
Geometric
calculations : 0
Interference
calculation
ICE
calculation 0
ICE
algorithm : Quick
ICE
samples number : 2000
Interference
criteria : 0
ICE
compatibility mode : 0
Use
unwanted signal type : Yes
Use
blocking signal type : No
Use
intermodulation signal type : No
Probability
result : Constant(0.0245)
ICE
calculation 1
ICE
algorithm : Quick
ICE
samples number : 2000
Interference
criteria : 0
ICE
compatibility mode : 0
Use
unwanted signal type : Yes
Use
blocking signal type : No
Use
intermodulation signal type : No
Probability
result : Constant(0.0245)
1.
Excercises
·
Frequency VR, f_vr
= 412.00625 MHz
·
Density of active interferer: dense_active
= 5 1/km²
·
Number of active interferer: n_active
= 9
Variations
·
dense_active = 10 1/km² p
= 4.2 %
·
dense_active = 10 1/km², n_active = 18 p
= 4.5 %
·
f_vr = 412.010 MHz p
= 1.6 %
·
f_vr = 412.030 MHz p
= 1.0 %
·
f_vr = 412.100 MHz p
= 0.65 %
