explain m10 - 1transmission planning
DESCRIPTION
1Transmission PlanningTRANSCRIPT
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1 NOKIA 6-60728/ TRANSMISSION PLANNING/ v 2.0
Transmission Transmission Planning Planning
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2 NOKIA 6-60728/ TRANSMISSION PLANNING/ v 2.0
Module objectives
9 DESCRIBE THE DIFFERENCES BETWEEN THE DIFFERENT TRANSMISSION PLANNING NETWORK TOPOLOGIES
9 LIST THE MAIN CHARACTERISTICS OF MICROWAVE LINKS
9 DESCRIBE THE TRANSMISSION TECHNIQUES
At the end of this module you will be able to
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3 NOKIA 6-60728/ TRANSMISSION PLANNING/ v 2.0
Content of Transmission Planning
9 PLANNING AND TOPOLOGIES9 LINK PLANNING9 FIXED LINE PLANNING
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4 NOKIA 6-60728/ TRANSMISSION PLANNING/ v 2.0
Transmission Planning
9 PLANNING AND TOPOLOGIES
9 LINK PLANNING
9 FIXED LINE PLANNING
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Cost for transmission lines accounts for a great portion of network operational costs per year
design a network that meets the design criteria with minimum overall costs!
Fixed part design
MSC
BSC Hub
BTS
BSS
BTS
BTS
BTS
Radio part design
BTS
BSS
BTS
BTS
BTS
Transmission Planning Basics
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6 NOKIA 6-60728/ TRANSMISSION PLANNING/ v 2.0
Transmission Planning Differences of RNP and TNP Viewpoints
Transmission capacity must be planned for the final phase of thenetwork, not phase by phase.
Suitability of a site for transmission can change from ideal to useless when choosing between two neighbouring candidates
Site changes can cause major changes in the transmission networktopology
No LOS in the new candidate change topology Interference problems re-planning of MW frequencies
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Transmission Planning Input Data
Customer input Allowed unavailability and performance figures Transmission media requirements: own network / leased line Blocking probabilities Protection level and type Existing transmission infrastructure Growth estimate and/or required spare capacity
Radio Network Planning input Number of BTSs Number of TRXs / BTS Nominal site locations
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8 NOKIA 6-60728/ TRANSMISSION PLANNING/ v 2.0
Network TopologiesBasics
Transmission topologies are chosen based on availability and protection requirements and availability of existing lines
Costs vs. fail safety (redundancy)
Real networks usually hybrid solutions
POINT-TO-POINT
MULTIDROP CHAIN LOOP
STAR (CONCENTRATION POINTS)
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9 NOKIA 6-60728/ TRANSMISSION PLANNING/ v 2.0
Network TopologiesDifferent Philosophies
High Transmission costs BSC used as a transmission
concentrator Small BSCs TRS capacity gain on A-ter Transmission costs gain
Low Transmission costs BSC used as a transmission
concentrator has a low influence on total cost
High capacity BSCs
MSC
BTSBSC
BTS
BTS
BTS
BSC/ MSC
BTS
BTS
BTS
BTS
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10 NOKIA 6-60728/ TRANSMISSION PLANNING/ v 2.0
Transmission Planning
9 PLANNING AND TOPOLOGIES
9 LINK PLANNING
9 FIXED LINE PLANNING
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11 NOKIA 6-60728/ TRANSMISSION PLANNING/ v 2.0
Microwave LinksBasics
The preferred media when building new access network links
High capacity transmission links
from 2x2Mbps to 16x2Mbps, 34Mbps and STM-1 (155 Mbps)
Contra: needs frequency license environment dependant link quality
(e.g. rainfall) LOS not always available
Pro: low operating costs easy to install flexible quick & reliable solution
Terminalstation A
Terminalstation B
Repeaterstation
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Microwave LinksTypes of MW
Long Haul Radios: ~ 30 - 80 km2 GHz, 7 GHz
Medium Haul Radios: ~ 25 - 45 km10 GHz, 13 GHz, 15 GHz
Short Haul Radios: ~ 5 - 30 km18 GHz, 23 GHz, 26 GHz, 38 GHz,
Nokia Metrohopper: < 1 km 57 GHz (uses oxygen absorption in air to limit range)
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13 NOKIA 6-60728/ TRANSMISSION PLANNING/ v 2.0
Microwave LinksModulation Methods
PSK - Phase Shift Keying There are several levels of PSK (2-PSK, 4-PSK, )
FSK - Frequency Shift Keying Fixed frequency for 0s and another one for 1s
QAM - Quadrature Amplitude Modulation A mixture of phase and amplitude modulation
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Microwave outages Equipment failures
use protected equipment hot / warm / cold -standby
Caused by nature temporary failures self-recovery use protected connections
Examples of natural outages: Heavy rainfall zones:
most severe in upper bands (2..3dB/km) significant above 10 GHz
Multipath fading problem with lower bands
Microwave LinksRadio Link Availability
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Microwave LinksHow to Avoid Interference
Use the highest available frequency band
Attenuate the Tx power to a minimum just to meet the required availability
Locate dishes as low as possible with maintaining the required LOS
Use big dishes
Use different polarisation
Select your channel(s) carefully
Maintain High-Low -rule on hub sites
Try to get similar received signal levels at hub sites
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High-End Low-End
Tx Freq.= f1
Rx Freq.= f2
Tx Freq.= f2
Rx Freq.= f1
f1 > f2
HIHIHILO
LO
Simple rule: keep all links in a site "high" or "low"
Microwave LinksHigh End & Low End
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To verify LOS between two planned sites Possibility to use a microwave link
Input Site locations Planned antenna height Direction to the other end of link Restrictions to cherry-picker, etc.
Output LOS/NLOS Minimum antenna height Exact antenna location (rooftop) Panorama picture with
landmarks and their directions Extra observations
(forests,building sites etc.)
Microwave LinksLOS Check
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Line-of-sight path needed between both nodes of a microwave link
Keep 1st Fresnel zone clear of obstacles
nth Fresnel zone: Ellipse around direct path, where path difference to direct line is n*/2.
db
b d kmf MHz
m= 274 [ ][ ]
[ ]
1st Fresnel zone2nd 3rd
Radius for n-th zone = b * sqrt(n)
Microwave LinksFresnel Zone
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Transmission Planning
9 PLANNING AND TOPOLOGIES
9 LINK PLANNING
9 FIXED LINE PLANNING
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Leased Lines Transmission lines rented from a 3rd party operator
Leased line provider is usually also a competitor
Contra High operating costs
Unpredictable lead times (installation)
Difficult to deploy (may include digging, groundwork..)
No control over the physical route or the quality of the link
Pro No implementation effort for
buyer
No extra infrastructure to buy
Long distances are uncritical
Analyse cost structure of Leased Line tariffs to decide whether LL or microwave links are more economical
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Leased LinesCost Examples
A
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K
3km30km
300km
0
500
1000
1500
2000
E
C
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p
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Leased Line Tariffs (Europe)
3km30km300km
Leased Line Tariff
10000
12000
14000
16000
18000
20000
22000
24000
26000
28000
30000
0 50 100 150 200 250
km length
U
S
D
p
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Leased Line costs vary greatly depending on country, link length, capacity, LL provider and the customer
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GENERAL RULE for TS allocation0 : Synchronization1 - 24 : TCH25 - 30 : TRX/BCF SIG31 : Loop control
Max 12 TRX per 2 Mbit frame
AbisInterface
AirInterface
BSCMSC
AInterface
AterInterface
TC SM
AterInterface
BTS2
BTS1
bits 1 2 3 4 5 6 7 8TS
0 Synchronisation1 BTS 12 TRX 13 BTS 14 TRX 25 BTS 16 TRX 37 BTS 28 TRX 19 BTS 210 TRX 211 BTS 212 TRX 313 BTS 314 TRX 115 BTS 316 TRX 217 BTS 318 TRX 319 BTS 320 TRX 421 BTS 322 TRX 523 BTS 324 TRX 625 BTS 1 TRX 1 S IG BTS 1 BCF S IG BTS 1 TRX 2 S IG26 BTS 1 TRX 3 S IG BTS 2 TRX 1 S IG BTS 2 BCF S IG27 BTS 2 TRX 2 S IG BTS 2 TRX 3 S IG28 BTS 3 TRX 1 S IG BTS 3 BCF S IG BTS 3 TRX 2 S IG29 BTS 3 TRX 3 S IG BTS 3 TRX 4 S IG30 BTS 3 TRX 5 S IG BTS 3 TRX 6 S IG31 Loop bits / LCB / MCB
BTS 11+1+1
BTS 21+1+1
BTS 32+2+2
Leased Lines2 Mbit Frame Allocation (Abis)
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Cross-Connects
Transmission equipment to branch data streams between different link sets
Non-blocking stage Each input stream is routed to an output stream
Tasks Switching between link sets Switching between timeslots of a PCM trunk Dropping & inserting timeslots
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3 x 2 Mbit/slinks
64 kbit/schannels
1 x 2 Mbit/slink
n
m
k
i < n+m+k
BSC
Total Traffic (Erl)Blocking Prob.
i = number of channels
Cross-ConnectsConcentration
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full 2 Mbit/s framesBSC
not full 2 Mbit/s frames
Cross-ConnectsGrooming
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Transmission media
Transmission techniques
Transmission methods
Fibre
Coaxial cable
Copper cable
Microwave radioTerrestrial/satellite
PDH SDH
PCMISDN ATM
Tran
smis
sion
equ
ipm
ent Transm
ission equipment
HDSLCATV
Transmission Techniques
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Transmission TechniquesMultiplexing
ITU- Standard: 8000 samples per sec @ 8bit = 64 kbit/s 32 * 64 kbit/s = 2 Mbit/s line
Lines can be de-/ multiplexed into lines of higher data rates 8Mbit/s, 34 Mbit/s, 140Mbit/s etc...
....
32 * 64 kbit/s
MUX
2 Mbit/s MUX/deMUX
1 sec1 sec
8 Mbit/s2 Mbit/sMUX/
deMUX
1 sec
....
32 * 64 kbit/s
MUX
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Transmission TechniquesPDH
PDH (Plesiochronous Digital Hierarchy) Voice spectrum ~ 4kHz Sampling rate 8 kHz 8 bits per sample Divided into 32 TS (TDM)
USA : 24 timeslots
Higher Order PDH Bitrates
Europe : 2.048 Mb/sUSA : 1.554 Mb/s
M
U
XM
U
X
140 M
34 M
34 M
34 M
34 M8 M8 M
8 M
8 MM
U
X
2 M
2 M
2 M
2 M
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SDH (Synchronous Digital Hierarchy) All network elements are synchronized to Primary Rate Clock (PRC) Worldwide standard : interfacing to USA possible
Europe USA STM- 1c (51.7 Mb/s) = STS-1 STM- 1 (155.52 Mb/s) = STS-3 STM- 4 (622.08 Mb/s) = STS-12 STM-16 (2488.32 Mb/s) = STS-48 STM-64 (9953.28 Mb/s) = STS-192
STM-4
STM-1
STM-1
STM-1
STM-1
Transmission TechniquesSDH
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Exercises / Questions
9 What would be the most appropriate network topology to use?
9 When should a leased line be used instead of a microwave link?
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References
1. Trevor Manning Microwave Radio Transmission Design Guide ISBN 1-58053-031-1.