spectrum occupancy measurement methodsspectrum occupancy measurement methods sjoert fleurke why are...
TRANSCRIPT
Spectrum Occupancy Measurement Methods
Sjoert Fleurke
Why Are We Doing Traffic Measurements?
We want to1. Serve new customers applying for a new
frequency.2. Verify complaints concerning channel
blocking from co-channel users.3. Establish that the spectrum is being used
efficiently.4. Detect trends in spectrum usage.5. Publish traffic figures of spectrum usage on
the internet.6. Check emergency channels not being used for
other purposes.
Monitoring Stations in the Netherlands
R&S ESMC receivers at 12 remote stations
20-1300 MHz
Measurement Methods
1.Continuous measurements.2.Systematic measurements.3.Random (Monte Carlo) measurements.
Channel traffic
dB(uV/m)
timetotaltimeoccupied
=ρ
time
Continuous Measurements
(s)
Continuous Measurements
• You get the exact occupancy during the measurement (actual occupancy).
• Using one measurement device, you can only measure one channel at a time.
Systematic Measurements
(s)
Revisit time = 1 second
Systematic Measurements
(s)
Revisit time = 2 seconds
Systematic Measurements
• You can sample lots of channels in the same time period.
• With short revisit times, the measurements are not done efficiently.
• With large revisit times, the measurements are more efficient, but if the revisit time is large the reliability is small.
Variance of Systematic Occupancy Estimation
0.0000000
0.0005000
0.0010000
0.0015000
0.0020000
0.0025000
0.0030000
0.0035000
0.0040000
0.0045000
1 6 11 16
revisit time (s)
varia
nce
independent
exponential
Erlang(2)
∆
−−
−
∆
−−
∆
−−
−−
+
∆
−−
∆−
=∆
)1(2)98(
cos)1(2
34cosh
)1(2)98(
sin9821
)1(234sinh
/)1(
ρρρ
ρρ
ρρρ
ρρ
ρρ
τρρ
τ
EBEB
EBEBSVar
Monte Carlo Measurements
(s)
Mean revisit time = 2 seconds
Random (Monte Carlo) Measurements
• All successive measurements are independent.
• This method estimates the actualoccupancy during the measurement period.
• The method is more difficult to implement than others.
Variance of Systematic Occupancy Estimation
0.0000000
0.0005000
0.0010000
0.0015000
0.0020000
0.0025000
0.0030000
0.0035000
0.0040000
0.0045000
1 6 11 16
revisit time (s)
varia
nce
independent
exponential
Erlang(2)
