Telecoms for Non-Engineers Adesoji Lawal

transcript

LAPLACE TELECOMS ACADEMY

4/30/2013

Presented By:

Adesoji Lawal

Principal Consultant

Telecoms For Non-Engineers

Telecoms Training

Table of ContentChapter 1: Basic Concepts

Chapter 2: Basic Blocks of Communication System

Chapter 3: Transmission Media

Chapter 4: Analog and Digital Modulation

Chapter 5: Fixed Telecoms Network

Chapter 6: Mobile Telecoms Network

Chapter 7: Datacom Network

Chapter 8: Internet Network

Chapter 9: Satellite Network

Chapter 10: Broadband Technologies

Radio Link Planning Principle

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Chapter 1: Basic Concept

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Low Versus High Frequency Signals

Voice and Data Signal

Electromagnetic Waves Propagation

Free Space Loss

Modulation

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Signals - Low Versus High Frequency Signals

Low Frequency LF Signals

LF refers to Radio Frequencies (RF) in the Range of 30 kHz–300 kHz

frequency = speed /wavelength (f = v /λ)

Low Frequency implies High Wavelength

High Wave length Implies Large Antennas.

LF use Mast Antennas with Heights of more than 150 Meters in many

Applications.

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Signals - Low Versus High Frequency Signals

Signals can be Characterized.

s(t) =Acos(2˄ft + ɵ)

Parameters For Characterization Include;

Amplitude – Signal Intensity/Loudness dB

Frequency – Signal Frequency/ Reoccurrence per Second Hz

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Signals -

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Signals – Voice and Data Signal

Voice Signals are Audio Signals

Audio Signal are Low Frequency Signal

Audio Signals can only few Kilometers

Radio Signal can be “Impregnated” with

Audio Signal - MODULATION

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Signals – Data Signal

What is Data – Digital Information in form of 1s and 0s (Bits)

They are pulse signals.

Unit of Measurement – Bits per Second

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Signals - Low Versus Higher Frequency Signals

Higher frequencies are HF, VHF, UHF, EHF

Higher Frequencies implies Smaller Antennas

Higher Frequencies also Implies Shorter Coverage Distance.

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Signals – Electromagnetic Waves Propagation

EM Wave travel through Free Space

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Multipath Propagation

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Signals – Free Space Loss

gradual loss in Signal Intensity with Distance Travelled

d in Km and f in MHz

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Signals – Modulation

WHY????????????????Answer =

1. Audio Signal CANNOT travel far – few kilometer

2. Radio Signal CAN travel very far – thousand of kilometer

Baby can only crawl, but mummy can

run extremely fast !!!!

If you want baby to arrive fast……..

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Modulation is the process of varying one or more properties of a

high-frequency periodic waveform called the carrier signal, with a

modulating signal which typically contains information to be transmitted.

Properties Include :

amplitude -volume

frequency - pitch

phase - timing

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Low Frequency Signal to be

Transmitted over a some

distance .

High Frequency Amplitude

Modulated Signal

Low Frequency Modulated

Signal

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An analog signal is a continuous waveform which changes in

accordance with the properties of the information being

represented.

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Digital information is a set of discrete values.

Time can also be represented digitally.

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The A/D conversion is performed by using a process called

Pulse Code Modulation (PCM). PCM involves three main steps:

· Sampling

· Quantization

· Coding

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Components of Radio Transmission System

Cellular Network Architecture

Site Configuration

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Transceiver Unit – Source of the Radio Signal

Unit is Watt W or decibel dB

Typical Output Power Level is 40 W

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Feeder 1/2., 7/8 Loss/Meter dB

Connectors 2- 4 dB Loss

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Antennas: Positive Gain , dBi and dBd

Point to Point Vs Point to Multipoint

Single Band Vs Multiband

Omni Vs Sector

Indoor Vs Outdoor

Radiation Pattern

Specification Sheet

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Site Configuration

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Site Configuration

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Site Configuration

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Site Configuration

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Site Configuration

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Site Configuration

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Site Configuration

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Site Configuration

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Site Configuration

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Site Configuration

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Site Configuration

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Site Configuration

Chapter 3: Transmission MediaRadio Link Planning Principle

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Optics Fiber

Radio Link

Satellite

Copper

Coaxial

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Optics Fiber

High Capacity

Less signal degradation

Low power

Immunity to Electrical Noise

Lower signal attenuation

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Wireless Radio Link

Faster to Deploy

Prone to EM Disturbance

Environmental Impact

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Satellite Link

Reliable

Efficient

Expensive

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Copper and Coaxial Cable Link

Twisted-pair cable

Widely Deployed for PSTN, ISDN & LANs

Cheaper

Prone to Cross-Talk

Chapter 4: Analog and Digital ModulationRadio Link Planning Principle

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Analog Modulation

Digital Modulation

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Analog Modulation – The Modulated Signal is a Continuous Wave Form

Amplitude Modulation AM s(t) =Acos(2˄ft + ɵ)

Frequency Modulation FM s(t) =Acos(2˄ft + ɵ)

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Analog Modulation – Modulated Signal is in Discrete Form (Positive and

Negative Pulses.

More Spectrum Efficient – More bps/Hz ( FASTER Communication)

More Prone to Error

Example Phase Shift Keying PSK s(t) =Acos(2˄ft + ɵ)

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PSTN - Analog Lines

ISDN – Digital Lines

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PSTN - public switched telephone network

telephone was wired to a local telephone exchange

exchanges were wired together with trunks

Networks were connected together in a hierarchical manner until they

spanned cities, countries and continents

SS7 network

Automated telephone exchanges now use digital switching rather than

mechanical or analog switching

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ISDN - Integrated Services Digital Network

Communications standards for simultaneous digital transmission of voice,

video, data, over PSTN

Integrates speech and data on the same lines

Chapter 6: Mobile Telecoms NetworkRadio Link Planning Principle

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Mobile Telephony Standard Evolution

Global System for Mobile Communications - GSM

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Better Quality of Service

World-wide Inter-operability

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Global System for Mobile Communications – GSM

GSM was first developed in the 1980s.

Radio frequencies of operation are 900 MHz and/o1800 MHz

digital system and a narrowband TDMA

modulation scheme chosen was Gaussian minimum shift keying (GMSK).

Frequency Division Duplex - 935–960 MHz and the downlink frequency is

890–915 MHz

Time Division Multiple Access

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Cellular Concept –Omni Site

Cellular Concept –Sectorized Sites

Handover – Communication Continuity

Chapter 7: Datacom NetworkRadio Link Planning Principle

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Computer Networks

Network Security

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LAN – Local Area Network - computer network

Switches and Routers are Key element

Interconnection of computers in a small area

Files and other information are easily shared

Printers and other expensive resource are shared

IEEE 802 family of IEEE standards

OSI Reference Data Communication Model

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LAN – Local Area Network - computer network

Interconnection of computers in a small area

Files and other information are easily shared

Printers and other expensive resource are shared

IEEE 802 family of IEEE standards

OSI Reference Data Communication Model

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Switches Segment a LAN

Router Segment WAN

IP Address

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Peer to Peer Communication

Chapter 8: Internet NetworkRadio Link Planning Principle

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global system of interconnected computer networks

GLOBALLY???? Chaos

Internet Protocol Suite (TCP/IP) was standardized

Each Internet computer, called a host

Services are Hosted on Internet Computer , called Servers

gain access through a commercial Internet Service Provider (ISP).

Chapter 8: Internet NetworkRadio Link Planning Principle

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Mobile Internet Evolution

Chapter 9: Satellite NetworkRadio Link Planning Principle

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Satellite Orbits

Satellite Launch

Satellite terminals

Telecoms Applications

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a satellite is an object which has been placed

into orbit by human Endeavour.

Satellite Orbits – LEO& GEO

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Satellite Launch

Rockets are used to send and put Satellite in the Earth’s orbit

Diameter of Earth - 12,753 km

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satellite Terminals

portable terminals

Operate under harsh Weather Condition

Service Availability

Relative High Cost !!!!!!!!!!!!!

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Chapter 10: Broadband TechnologiesRadio Link Planning Principle

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Telecommunications signal or device of greater bandwidth

High data rate connection to the Internet

Ranging from 64 kbit/s up to 4.0 Mbit/s

Enabling Technologies

DSL – Digital Subscriber Line

Data throughput of consumer DSL services typically

ranges from 256 kbit/s to 20 Mbit/s

ISDN - Integrated Services Digital Network

bandwidths of 256 kbit/s or mor

Thank U OOOOOoooooo

4/30/2013

Telecoms for Non-Engineers Adesoji Lawal

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