BFWAtg(00)30 Co-existence of MP- MP and PMP Systems Philip Whitehead Radiant Networks PLC
Apr 01, 2015
BFWAtg(00)30
Co-existence of MP- MP and PMP Systems
Philip Whitehead
Radiant Networks PLC
BFWAtg(00)30
Coexistence
• Definition:– The ability of two (or more) systems to operate in the
presence of mutual interference with acceptable degradation of performance
• Two main scenarios– Systems operating on the same channels in adjacent or
nearby areas.– Systems operating in overlapping areas and using adjacent
or near- adjacent channels.
BFWAtg(00)30
• No base stations• Short paths• All antennas are directional• Low antenna heights• Low transmitter power• Very good frequency re-use• Detect and avoid interference
Improved co-existence
General Characteristics of Mesh Systems
BFWAtg(00)30
Main conclusions from the study
• Mesh and PMP systems can easily co-exist• Guard bands can be reduced or even zero• Co-channel systems can be very close together
(closer than PMP – PMP)• Rain fading has negligible impact
BFWAtg(00)30
Methodology
• Simulation of (random) mesh with large number of subscribers
• 20GHz - 43.5GHz considered – results presented for 28GHz band
• Multiple interferers • 3-D geometry • Effects of buildings (LOS probability calculated)• Atmospheric attenuation and rain fading according to
ITU-R
BFWAtg(00)30
Geometry
CL
mesh X-dim
mes
h to
t Y
-di
m
Base Station Receivercell radius
90
Meshm
esh
boun
dar
y
BFWAtg(00)30
3D Geometry
Mesh rx
hub
sub
Mesh tx
BFWAtg(00)30
Link Length Distribution
Length distribution of mesh links
0.0%
5.0%
10.0%
15.0%
20.0%
1 2 3 4 5 6 7 8 9 10
Max range (100s of m)
Fra
ctio
n o
f to
tal
220-link
140-link
BFWAtg(00)30
Horn Antenna RPE
90 60 30 0 30 60 9040
30
20
10
0
Relative Power (dB)
Bearing (degrees)Azimuth Elevation
SLLSLLP e HPBW
28.2)1()(
BFWAtg(00)30
28GHz Antenna RPE
0 20 40 60 80 100 120 140 160 18040
30
20
10
00
40
dBsubs a( )
dBmesh b( )
1800 a b
BFWAtg(00)30
Main lobe Characteristics
0 2 4 6 8 10 12 1418
15
12
9
6
3
00
18
dBsubs a( )
dBmesh b( )
150 a b
BFWAtg(00)30
BS Interference (dBm) as a function of BS distance (km) and height (m)
BS distance (km)
BS
hei
ght a
bove
gro
und
(m)
Notes: Rayleigh parameter = 20m
System Spacing vs. BS Antenna Height
BFWAtg(00)30
MP-MP to PMP Subscriber Co-channel
heig
ht a
bove
gro
und
(m)
Distance from mesh (km)
BFWAtg(00)30
MP-MP to PMP Subscriber Co-channel (BS 12km from mesh edge)
Distance past BS from mesh (km)
He
igh
t a
bo
ve
gro
un
d
(m)
BFWAtg(00)30
Co-channel conclusions
• A mesh can be placed close to a PMP system, with negligible interference
• Spacing can be even less when the mesh uses “self adaptation” (down to zero?)
• Mesh antenna RPEs are not critical (low cost antennas can be used)
• Rain fading effects are negligible.
BFWAtg(00)30
Mesh to PMP hub (50m elevation) dry weather, adjacent channel
Interference power profile
0
0.5
1
1.5
2
2.5
3
3.5
4
-200 -150 -100 -50 0
Rx power (dBm)
Rel
ativ
e p
rob
abil
ity
0.0001
0.001
0.01
0.1
1
Cu
mu
lati
ve p
rob
abili
tyInterference
CDF
Threshold
BFWAtg(00)30
Mesh to PMP hub (50m elevation) dry weather, adjacent channel
Weather Max. interference power
Probability of exceeding threshold
Dry -82.2 dBm 37.4% Random rain front
-78.5 dBm 31.9%
Random rain storm
-79.4 dBm 36.0%
Uniform rain -78.7 dBm 28.2%
Mesh to PMP hub (50m elevation) dry weather, adjacent channel
BFWAtg(00)30
Mesh to 50m PMP hub: uniformly wet weather, single-channel guard band
Interference power profile
0
0.5
1
1.5
2
2.5
3
3.5
4
-200 -150 -100 -50 0Rx power (dBm)
Rel
ativ
e p
rob
abil
ity
0.0001
0.001
0.01
0.1
1
Cu
mu
lati
ve p
rob
abili
tyInterference
CDF
Threshold
BFWAtg(00)30
Mesh to PMP hub (50m elevation) one guard channel
Weather Max. interference
power Probability of exceeding threshold
Dry -103.2 dBm 0.00% Random rain front
-99.7 dBm 0.02%
Random rain storm
-100.4 dBm 0.00%
Uniform rain -99.7 dBm 0.02%
BFWAtg(00)30
Mesh to 25m PMP hub: uniformly wet weather, single-channel guard band
Interference power profile
00.5
11.5
2
2.53
3.54
-200 -150 -100 -50 0
Rx power (dBm)
Rel
ativ
e p
rob
abil
ity
0.0001
0.001
0.01
0.1
1
Cu
mu
lati
ve p
rob
abili
tyInterference
CDF
Threshold
BFWAtg(00)30
Mesh to PMP subscriber, adjacent channel
Interference power profile
0
0.51
1.52
2.5
33.5
4
-200 -150 -100 -50 0
Rx power (dBm)
Rel
ativ
e p
rob
abil
ity
0.0001
0.001
0.01
0.1
1
Cu
mu
lati
ve p
rob
abili
tyInterference
CDF
Threshold
BFWAtg(00)30
Weather Max. interference power
Probability of exceeding threshold
Dry -66.5 dBm 11.2% Random rain front
-70.0 dBm 12.1%
Random rain storm
-70.9 dBm 11.9%
Uniform rain -64.7 dBm 12.3%
Mesh to PMP subscriber, adjacent channel
BFWAtg(00)30
Mesh to cell-edge PMP subscriber, single-channel guard
band
Interference power profile
00.5
11.5
22.5
33.5
4
-200 -150 -100 -50 0
Rx power (dBm)
Rel
ativ
e p
rob
abil
ity
0.0001
0.001
0.01
0.1
1
Cu
mu
lati
ve p
rob
abili
tyInterference
CDF
Threshold
BFWAtg(00)30
Conclusions for Overlapping systems
• Guard band of zero to one channel is sufficient for a “random” mesh
• Self- adapting mesh can work with zero guard band• Antenna RPEs not critical (low cost antennas
possible)• Rain fading effects are negligible