microwave basics
TRANSCRIPT
Marconi Academy2 P SR540 E V4.2
Microwave Radio Technology
STM-1/42 Mbit/s
34 Mbit/s
2 Mbit/s34 Mbit/s
STM-1
STM-1
STM-1
STM-1
♦ Free-space propagation of electromagnetic waves
♦ Line of sight connection♦ Frequency range
• 3 to 38 GHz♦ Short-haul and long-haul
systems
Marconi Academy3 P SR540 E V4.2
Microwave Radio Technology
Long-haul system♦ Range
• 15 to 40 km(w/o diversity)
• 40 - >80 km(with diversity)
♦ Frequency range• 3 to 13 GHz
♦ Transmission capacity• 2 to 622 Mbit/s
Short-haul system♦ Range
• up to approx. 20 km♦ Frequency range
• 15 to 38 GHz♦ Transmission capacity
• 2 to 622 Mbit/s
Wave-guide
Indoor Unit
Outdoor Unit
Coaxialcable
Marconi Academy4 P SR540 E V4.2
Microwave Radio Technology - System Designations
Long-haul systems♦ MDRS 155/7500 - 64 QAM
• SDH microwave radio - 7R design♦ MDRS 155/6800 - 64 MLQAM E♦ MDRS 155/13000 - 128 MLQAM E
• SDH microwave radio - ETSI design• Short name: MDRS 155 E
♦ MDRS 2-34/7400 - 16 QAM♦ MDRS 2x34/7400 - 64 QAM
• PDH microwave radio - 7R design
Short-haul systems♦ MDRS 155/18700 - 16 QAM N
• SDH microwave radio - "NKRS"• Short name: MDRS 155 N
♦ MDRS 155/23000 - 16 MLQAM C• SDH microwave radio - "Compact"• Short name: MDRS 155 C
♦ MDRS 155/26000 - 128 MLQAM S• SDH microwave radio• Short name: MDRS 155 S
Marconi Academy5 P SR540 E V4.2
Circulator, Filter(CBN)
WaveguideRF
Circulator, Filter(CBN)
Waveguide
f [GHz]
Channel
BB = Baseband
e.g. 155 Mbit/s
Classical Design
Channel
Demodulator16 - 128 QAM
Modulator16 - 128 QAM
IF = Intermediate frequency
e.g. 140 MHz
RF = Radio frequency
e.g. 7.5 GHz, 18.7 GHz
TXTransmitter
RXReceiver
Marconi Academy6 P SR540 E V4.2
Channel 3
Channel 2
Channel 1
Rx side
RXDMChannel 3
Channel 1
Channel 2
MD
MD
MDChannel 3
Tx side
Channel 1MDTX
Tx side Rx side
DMRXCBNCBNTXMD
DM
DM
DM
RX
RX
RX
Classical Design
TX
TX
TX
f1 f2 f3
f1
f2
f3
f1 f2 f3
Band filter Circulator Absorber
Marconi Academy7 P SR540 E V4.2
f1’f1b
Microwave Radio Technology - Frequency Patterns
f1f1a
CBN CBN
TXMD
DMRX
f1a
f1a
f1a
f1b
DM RX
TX MD
f1b
f1b
f1f1a
f2f2a
f4f4a
f3f3a
f1`f1b
f2`f2b
f4`f4b
f3`f3b
Lower band Upper band
Allocated frequency range
Duplex spacing
Channel spacing
Channel width
Marconi Academy8 P SR540 E V4.2
f1f1a
f2f2a
f3f3a
f5f5a
f4f4a
f6f6a
Hhorizontal
Vvertical
f1f1a
f1f1a
f2f2a
f4f4a
f3f3a
f4f4a
f3f3a
f2f2a
Hhorizontal
Vvertical
90°
Hhorizontal
Frequency Patterns - Transmission via 2 Polarizations
1st polarizationV: vertical
Orthomode
transducer (OMT)
V
TXMD
DM RX
f1a
f1b
CBN
f1
TXMD
DM RX
f1a
f1b
CBN
f1
H
ACDP: Adjacent Channel Dual Polarisation
CCDP: Co- Channel Dual Polarisation
2nd polarization
Marconi Academy9 P SR540 E V4.2
16 QAM
1024QAM512QAM256QAM
128QAM
64QAM
16QAM
4PSK
Se
ns
itiv
ity
Channel width
f1f1a
f2f2a
f4f4a
f3f3a
Channel width
Bandwidth/Channel Width
Channel/bandwidths ♦ Transmission
• SDH
• 155 Mbit/s
♦ 16 QAM • < 45 MHz
• MDRS 155/...- 16 MLQAM
♦ 64 QAM• < 30 MHz
• MDRS 155/...- 64 MLQAM
♦ 128 QAM• < 26 MHz
• MDRS 155/...- 128 MLQAM
The higher the modulation stage ♦ the smaller the channel/
bandwidth (advantage)
♦ the more sensitive to
interference (disadvantage)
64 QAM
128 QAM
Marconi Academy10 P SR540 E V4.2
Frequency Patterns - Channel Spacings
3 4 5 6 7 8 9 1 0 1 1 1 2 1 3
f4f4a
f3f3a
Channelspacing
ITU-R F.382 6 Ch. 29 MHz 3824.5 - 4182.5 MHz
ITU-R F.382 6 Ch. 29 MHz 3413.0 - 3771.0 MHzITU-R F.497 8 Ch. 28 MHz 3422.5 - 3884.5 MHz
ITU-R F.635 7 Ch. 40 MHz 3620 - 4180 MHz
ITU-R F.635* 7 Ch. 40 MHz 3610 - 4170 MHz
ITU-R F.635 4 Ch. 80 MHz 3630 - 4190 MHz
4 (3.6/3.8/3.9 GHz)
ITU-R F.1099 7 Ch. 40 MHz 4430 - 4970 MHz
ITU-R F.1099 4 Ch. 80 MHz 4450 - 4990 MHz 5 (4.7 GHz)
ITU-R F.383 8 Ch. 29.65 MHz 5945.20 - 6404.79 MHzITU-R F.497 8 Ch. 28 MHz 5689 - 6151 MHz
6L (6.2 GHz)
ITU-R F.384 8 Ch. 40 MHz 6460 - 7080 MHz 6U (6.8 GHz)
ITU-R F.385 5 Ch. 28 MHz 7442 - 7708 MHz
ITU-R F.385* 5 Ch. 28 MHz 7428 - 7722 MHz
ITU-R F.385 5 Ch. 28 MHz 7121 - 7429 MHz
ITU-R F.385 5 Ch. 28 MHz 7457 - 7737 MHzITU-R F.385 8 Ch. 28 MHz 7442 - 7883 MHz
7 (7.5 GHz)
ITU-R F.386 8 Ch. 29.65 MHz 7747.70 - 8266.57 MHzITU-R F.386 3 Ch. 28 MHz 8293 - 8468 MHz
8 (8 GHz)
ITU-R F.387 8 Ch. 28 MHz 12765 - 13227 MHz 13 (13 GHz)
ITU-R F.387 12 Ch. 40 MHz 10715 - 11685 MHz
ITU-R F.387 12 Ch. 40 MHz 10695 - 11665 MHz
ITU-R F.387 12 Ch. 40 MHz 10735 - 11665 MHz
11 (11 GHz)
"Free" frequency patterns in Germany
Marconi Academy11 P SR540 E V4.2
40 MHz frequency pattern (e.g. 6.8 GHz)
Channel spacing40 MHz
f1
f1
f2 f4
f3 f4
f3
f2
64 QAM
Channel width30 MHz
Exploitation of Frequency Patterns
f1
f1
f2 f4
f3 f4
f3
f2
128 QAM
28 MHz frequency pattern(e.g. 7.5 GHz or 13 GHz)
f5
f5
f6
f6
f1
f1
f2 f4
f3 f4
f3
f2
26 MHz Channel width
128 QAM
f1
f2
f3 f5
f4 f6
64 QAM
30 MHz Channel width
Channel spacing 28 MHz
Marconi Academy12 P SR540 E V4.2
10 1001 2 5 20 500.01
0.1
1
10
100
dB/km
f/GHz
Rain25mm/h
Rain16mm/h
Rain150mm/h
mm/h (millimeters per hour)
Additional Attenuation
Attenuation due to precipitation ...♦ depends on the intensity
♦ depends on the radio hop length
♦ depends on the frequency
Marconi Academy13 P SR540 E V4.2
218 m
Half-power beamwidth, e.g. ...°
λ
Case 1 + =
λ = wavelength
Case 2 + =
Case 3 + =
Additional Attenuation - Multipath Propagation
e.g. 50 km approx. .... m
Marconi Academy14 P SR540 E V4.2
∆ ∆
Microwave Radio Technology - Space Diversity
DMRX
TX MDCBN
Main
+DMRX
TXMD CBN
Main
+
STM-1 STM-1
CBN
Div
RX
Lengthcompensation
CBN
Div
RX
Marconi Academy15 P SR540 E V4.2
Maximum Radio Hop Lengths
Space Diversity
Climate: Central Europe; BER=2x10E-5; Feeder: 2x30m; w/o Interference; Pout: 0.001%; rain is not considered
0 10 20 30 40 50 60 70 80 90 100
Hop Length / km
MDRS 155/3900-64 MLQAM
With Space Diversity
MDRS 155/4700-64 MLQAM
With Space Diversity
MDRS 155/6200-64 MLQAM
With Space Diversity
MDRS 155/6800-64 MLQAM
With Space Diversity
MDRS 155/7500-64 MLQAM
With Space Diversity
MDRS 155/8000-64 MLQAM
With Space Diversity
MDRS 155/13000-64 MLQAM
With Space Diversity
1.2 m
2 m
3 m
Antennae-
Diameter
Marconi Academy16 P SR540 E V4.2
Microwave Radio Technology - Frequency Diversity
f1a
f3a
f1b
RPS CBNChannel 1
MD TX
MD TX
DM
f3b
RX
RXDM
f1 f3
f
f3f3a
f1f1a
f3’f3b
f1’f1b
Marconi Academy17 P SR540 E V4.2
b 211λ
zone:dst Fresnel ⋅+
Microwave Radio Technology - Fresnel Zone
Radius b
Distance d
Marconi Academy18 P SR540 E V4.2
Microwave Radio Technology - System Designation
3 + 1N
Betriebskanal (BK)Operation Channel (OP)
MErsatzkanal (EK)
Protection Channel (PR)
RPSCBN
STM-1
STM-1
STM-1
DM RX
TXMD
DM RX
TXMD
DM RX
TXMD
DM RX
TXMD
OP1
OP2
OP3
PR
RPS
CBNDM RX
TXMD
DM RX
TXMD
DM RX
TXMD
DM RX
TXMD
STM-1
STM-1
STM-1
OP1
OP2
OP3
PR
CBN
OP1
PR
OP2
OP3
Hhorizontal
Vvertical
OP1 PR
Hhorizontal
Vvertical
OP2 OP3
Marconi Academy19 P SR540 E V4.2
CBN
CBN
System Designation - 3+1 Configuration Example
PR1 TXMD PR1RX DM
RXDMOP1
OP2
OP3
PR1
RXDM
RXDM
RXDM
STM-1
STM-1
STM-1
TX MDOP1
OP2
OP3
PR1
TX MD
TX MD
TX MD
STM-1
STM-1
STM-1
TXMDOP1
OP2
OP3
TXMD
TXMD
STM-1
STM-1
STM-1
RX DMOP1
OP2
OP3
RX DM
RX DM
STM-1
STM-1
STM-1
Occas. traffic (OT)
Occas.traffic (OT)
Occas.traffic (OT) Occas.
traffic (OT)
Marconi Academy20 P SR540 E V4.2
CBN
10dBCBN
1+0 Equipment Protection - "1+1 HSB" Configuration
RPS RPS
f1f1a
f1`f1b
f1a
f1a
TX
TX
Station BStation A
Ch. 1
(STM-1)Ch. 1
(STM-1)
DM RX
f1b
DM RXf1b 10dBOP
PR f1b PR
TX MDf1b
TX MD
OP
OP
PR
MD
MD
RX
f1a
RXf1a
DM
DM
PR
OP
Marconi Academy21 P SR540 E V4.2
1+0 Equipment Protection - Space Diversity
f1f1a
f1`f1b
CBN
Station BStation A
Ch. 1
(STM-1)Ch. 1
(STM-1)RPS RPS
f1b PR
TX MDf1b
TX MD
OP
OP
PR
MD
MDf1a
f1a
TX
TX
CBN
RX
f1a
RXf1a
DM
DM
PR
OP
CBN
CBN
DM RX
f1b
DM RXf1bOP
PR
Marconi Academy22 P SR540 E V4.2
TXMDCh. 1
(STM-1)
DM RX
horizontal f1a
f1b
Ch. 1
(STM-1)
DMRX
TX MD
f1a
f1b horizontal
140MHz
140MHzCBN CBN
Ch. 2
(STM-1)
DMRX
TX MD
f1a
f1b
TXMDCh. 2
(STM-1)
DM RX
vertical
f1a
f1b vertical
140MHz
140MHz
PWPW
CBN CBN
OP2f1
V
f1OP1
f
H
Block Diagram - 2+0 Configuration with XPIC
Clock synchronizationData compensation
V VH H
2 Waveguidepro Station
Marconi Academy23 P SR540 E V4.2
RXTX
HH
MD CBN CBN
RXTX
VV
MD CBN CBN
PW PW
Terms of Microwave Radio Technology - XPIC Principle
H
H + x•V
f
H
V
XPD
XPIC
f
H
V
ATDE
x•V
x•H-x•V
-x•H
V + x•H
ATDE +
ATDE +V
Marconi Academy24 P SR540 E V4.2
Interferences♦ Reason: Interferences on the same channel
Radio hop identifier ♦ prevents the transmission of a co-channel interferer
(e.g due to overlengths)
Terms of Microwave Radio Technology - Identifiers
0001
0010
0011
0100
f1a
f1b
f1a
f1b
f1a
f1b f1b
f1a
Marconi Academy25 P SR540 E V4.2
TX
Terms of Microwave Radio Technology - System Overview
Max. powere.g. +31 dBm
[1.25 W]
Output power
min. powere.g. -73 dBm
[50 pW]
Fadingmargin
Free space attenuation e.g. 143.9 dB
(Distance d = 50 km)(Frequency: f = 7.5 GHz)
( )f[GHz]d[km]log2092.40
a ⋅⋅+=
CBN
waveguide
e.g.5.3 dB
CBNwaveguide
Antenna
gain
e.g.41.4 dB
Antenna
gaine.g.
41.4 dB
CBNwaveguide
CBN
waveguidee.g.
5.3 dB
System attenuation
(e.g. 71.7 dB)
Input power
RX
System gain
Marconi Academy26 P SR540 E V4.2
[ ]
[ ]s Times
bitsrate Data
bits errors MeasuredBER
⋅
=
810072.1
1mins
Mbits155.52
bits100BER:Example −⋅=
⋅
=
Bit Error Ratio (BER)
Radio hopinterference
BER measuringunit
1E-9
1E-8
1E-7
1E-12
1E-11
1E-10
1E-6
1E-5
1E-4
BER
-70 -65 P-75 RX[dBm]
at A
Marconi Academy27 P SR540 E V4.2
Radio hopFailures
caused by various factors
Errored secondsES
0 < BER < 1E-3
Degraded minutes DM
1E-6 < BER < 1E-3
Error-free secondsEFS
BER = 0
Performance
Severely erroredseconds SES
BER > 1E-3(t < 10s)
Transmission Performance
ITU-T G826
> 30% errored blocks(t > 10 s)
< 30% errored blocks
< 30% errored blocks
0% errored blocks
> 30% errored blocks (t<10s)
Unavailable time Available time
Transmission performance of radio hops
Availability
ITU-T G821
BER > 1E-3 (t > 10 s) 0 < BER < 1E-3
Marconi Academy28 P SR540 E V4.2
• ES - (Errored Seconds)• SES - (Severely Errored Seconds)• UT - (Unavailable Time)
(SDH: UAS - Unavailable Seconds)
BER 1E-1 (0.1)
BER 1E-2 (0.01)
BER 1E-3 (0.001)
BER 1E-4 (0.0001)
BER 1E-5 (0.00001)
BER 1E-6 (0.000001)
BER 1E-7
BER 1E-8
BER 1E-9
BER 1E-10
BER 1E-11
t [s]
Transmission Performance
Marconi Academy29 P SR540 E V4.2
Tx side
T´ A´Z´ B´
C´
D´
TXMD
PW
TA ZB
C
D
Rx side
RX DM
PW
Terms of Microwave Radio Technology - Interfaces
T´ - Input Baseband
Z´ - Output Modulator (ZF)
A´ - Output Transmitter
B´ - Output RF Filter (TX)
C´ - Output Circulator (TX)
D´ - Input OMT (TX)
D - Output OMT (RX)
C - Input Circulator (RX)
B - Input RF Filter (RX)
A - Input Receiver
Z - Input Demodulator (ZF)
T - Output Baseband
Marconi Academy30 P SR540 E V4.2
1 1 0 0 0 0 1 1 0 0 0
Clock
Data 0 0 0 0 0
1 1 0 0 0 V 1 1 A 0 0 V A 0 0 V
HDB3
Baseband Code
CMI code♦ CMI - Coded Mark Inversion
♦ Free from DC due to alternating polarity
♦ Used for bit rates > 140Mbit/s• Binary value: log. 0
− first clock half always negative − second edge always positive − always positive rising edge
• Binary value: log. 1− entire clock period alternating with
positive and negative potential
HDB-3 code♦ Modified AMI code
♦ Transmission code for 2, 8 and 34 Mbit/s
• Additional bit V prevents sequences of
more than three log. 0s.
• Additional bit has same polarity as last
data bit.
• If no or an even number of log. 1s
follows two violation bits, an AMI
additional pulse is inserted three bits
before the next violation bit.
1 1 1 0 0 1 0 1 0 1 0
Clock
Data
CMI