transmission planning

EXPLAIN v3.0 - Nokia 2001 – DVassena

5. Transmission Planning5. Transmission Planning

Summary

• Technologies

• Radio Network Planning Process

• Radio Media & Model Tuning

• Network Dimensioning

• Transmission Planning

• Parameter Planning & Optimisation

• Network Capacity Evolution

• Planning Tools



Transmission PlanningEXPLAIN CHAPTER 5

• Transmission Planning (3)

• Network Topologies (2)

• Microwave Links (8)

• Leased Lines (3)

• Cross Connects (3)

• Transmission Techniques (4)



• 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 the network, 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 network topology• 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



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 equipmenthot / warm / cold -standby

• caused by naturetemporary failuresself-recoveryuse protected connections

• Examples of natural outages:• heavy rainfall zones:

most severe in upper bands (2..3dB/km)significant above 10 GHz

• multipath fadingproblem 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

HIHI HILO

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.

d

b

bd km

f MHzm274

[ ]

[ ][ ]

1st Fresnel zone2nd 3rd

Radius for n-th zone = b * sqrt(n)

Microwave LinksFresnel Zone



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

Aus

tria

Bel

gium

Den

mar

k

Finl

and

Fran

ce

Ger

man

y

Gre

ece

Irela

nd Italy

Net

herla

nds

Nor

way

Por

tuga

l

Spa

in

Sw

eden

Sw

itzer

land U

K

3km30km

300km

0

500

1000

1500

2000

EC

U p

er m

onth

Leased Line Tariffs (Europe)

3km

30km

300km

Leased Line Tariff

10000

12000

14000

16000

18000

20000

22000

24000

26000

28000

30000

0 50 100 150 200 250

km length

US

D p

er m

on

thLeased 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

Ater’Interface

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 SIG BTS 1 BCF SIG BTS 1 TRX 2 SIG

26 BTS 1 TRX 3 SIG BTS 2 TRX 1 SIG BTS 2 BCF SIG

27 BTS 2 TRX 2 SIG BTS 2 TRX 3 SIG

28 BTS 3 TRX 1 SIG BTS 3 BCF SIG BTS 3 TRX 2 SIG



31 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

HDSL

CATV

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 M

8 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-1STM-1STM-1STM-1

Transmission TechniquesSDH

transmission planning

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