explain m10 - 1transmission planning

1 NOKIA 6-60728/ TRANSMISSION PLANNING/ v 2.0

Transmission Transmission Planning Planning


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


Content of Transmission Planning

9 PLANNING AND TOPOLOGIES9 LINK PLANNING9 FIXED LINE PLANNING


Transmission Planning

9 PLANNING AND TOPOLOGIES

9 LINK PLANNING

9 FIXED LINE PLANNING


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


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


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


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)


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




9 LINK PLANNING



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


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)


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


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


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


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


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


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




9 LINK PLANNING



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


Leased LinesCost Examples

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K

3km30km

300km

0

500

1000

1500

2000

E

C

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o

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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


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)


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


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


full 2 Mbit/s framesBSC

not full 2 Mbit/s frames

Cross-ConnectsGrooming


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


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


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


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


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?


References

1. Trevor Manning Microwave Radio Transmission Design Guide ISBN 1-58053-031-1.

explain m10 - 1transmission planning

Documents

transmission networktopology

transmission techniquesat

transmission lines accounts

minimum overall costs

low operating costs

protection requirements

microwave linksbasics

final phase of thenetwork