Celular Lecture 2 [1]

8/8/2019 Celular Lecture 2 [1]

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Cellular Technologies slide 1 COMP 3054

Hisham Alasady, PhD.

Part IIntroduction to Wireless

Telecommunication Systems & Networks


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Objectives

Discuss the general history and evolution of wirelesstechnology from a North American viewpoint and explain the

cellular radio concept Discuss the evolution of modern telecommunications

infrastructure.

Discuss the structure and operation of the PSTN, the PDN,

and the SS7 Network. Explain the basic structure of Broadband Cable TV systems.

Explain the basic concept and structure of the Internet.

Discuss the usage of the various telecommunicationsnetworks and their relationship to one another.

Discuss wireless network applications and the future of thistechnology.


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The History and Evolution of Wireless RadioSystems

Early Amplitude Modulation (AM) wireless systems

Maxwell (1865), Hertz (1887), and Marconi (Dec. 12/1901) firsttransmission across the Atlantic Ocean

Crude early low-frequency transmitters Used on-off keying (i.e. Morse code)

Figure (1): Typical early wireless

Transmitter


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The first broadcast

1900s Fessenden

1910s Navy ship-to-ship and ship-to-shore radio development

1920s Short-wave radio development

1930s & 1940s saw more advancement in radio technology with theinvention of TV, radar and vacuum tubes to generate microwaves.

Modern AM

Newer uses of AM include of QAM.

QAM is a hybrid form of AM and PM

QAM is considered a digital modulation (today it is extensively used)

The development of FM

Armstrong started his work on FM in 1920s and completed it in 1930s

FM broadcasting become popular in late 1960s and early 1970s

1G AMPS is an FM based system (introduced in the US in 1983)


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The evolution of digital radio In 1936 AT&T tested the first experimental broadband coaxial cable

In 1941 the first L1 system that could handle 480 call was installed

In 1947 the first microwave system was installed (Boston - New York) By the 1970s AT&T microwave relay system carries 70% of its voice traffic

and 95% of its broadband television traffic.

Microwave digital radio system become popular in 1970s and 1980s

Today, many SP and cellular operators are using digital microwave systems

to backhaul aggregated bandwidth signals. The cellular telephone concept

The first mobile radios (HD) were used primarily by police departments

It consisted of a single, tall, centrally located tower with AP TX.

These systems have a limited capacity due to a limited frequencyallocation

In late 1960s AT&T proposed and in 1971 tested a cellular system thatconsisted of many towers, each low in height using a low power TX.

In 1983 the first (1G) mobile cellular system (AMPS) deployed in US


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The Development of ModernTelecommunications Infrastructure

The Public Switched Telephone Network (PSTN)

Consists of copper pairs, digital network and digital switch

The local exchange Subscribers connected through copper wires

Intraoffice calls Subscribers connected to the same switch

Connection-switched calls

Figure (2): A PSTN intraoffice callthrough a local exchange


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The Public Switched Telephone Network (PSTN)

Interoffice calls Subscribers connected to different switches

Required a Trunk link

T-carrier transport

Figure (3): A PSTN interoffice callover an enter-exchangetrunk line


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Signaling System #7 (SS7) Without SS7 PSTN used in-band signaling

Using separate facility to perform a call

routing function (out-of-band)

signaling

SS7 is a packet network with: Signal transfer points (STP)

Service switching points (SSP) Service control points (SCP)

Interface between SS7 and databases

Operations support systems

SS7 set up and tear down

interoffice and long distance calls

Figure (4): The network elementsof the SS7 system


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The Public Data Network (PDN) Connection oriented services

Permanent virtual circuit (PVC)

Switched virtual circuit (SVC)

Connectionless systems Less overhead and faster

Private data networks Owned or leased from service provider

Virtual private data networks Use the public data network

Tunneling protocols Maintaining privacy

Figure (5): A depiction of the PDN


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Broadband Cable Systems

Legacy cable systems

Two-way hybrid fiber-coaxial systems DOCSIS standard

Figure (6): Modern two-way hybridfiber-coaxial cable-TV

system with fiber node


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The Internet

Internet is world largest

computer network Wide area networks

Local area networks

Figure (7): Conceptual structure ofthe Internet


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Cellular Telephone Systems

First generation (1G) used analog technology (AMPS)

Second generation (2G) used digital technology (GSM & CDMA) Second and half generation (2.5G) is a medium speed data access

system (GPRS & IS-95B)

Third generation (3G) is a high speed data access system (UMTS,EGDE, WCDMA, CDMA2000)

Fourth generation (4G) is a broadband universal data access system(LTE, WiMAX)


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Overview of Existing Network Infrastructure

Evolution of different technologies

Multimedia traffic capability (voice, data and video)

Analog versus digital Metropolitan area networks

VoIP and wireless technologies


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Overview of Existing Network Infrastructure

Figure (7): Todays existing network infrastructure


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Wireless Network Applications: WirelessMarkets

Voice Network Evolution

The development of voice-oriented wireless networks began on 1970sAT&T`s Bell Labs

1G FDMA analog cellular system was developed in North America but itfirst deployed in Nordic countries in 1982 as NMT system

In 1983 started its deployment in North America as AMPS system

The 2G TDMA digital cellular was deployed in late 1992 as GSM system

Today more that 70% of cellular users are serviced by GSM systems North American version of TDMA 2G was introduced in early 1990s as

IS-136.

The most recent entry into the cellular system is the CDMA technology

started in 1995 in US. The Japanese TDMA 2G version is the Pacific Digital System (PDS)


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Wireless Network Applications: WirelessMarkets

Data Network Evolution

in 1985 the radio-based LAN started when the FCC opened the ISMbands (between 920 MHz and 5.85 GHz)

GPRS and EDGE are the data version for GSM with rate of 20 to 50kbps (SMS, IM, MMS).

The CDMA system can support data rate or 14.4 to 56 kbps (IS-95-B)

The cdma2000 offers data rate of up to 144 kbps.

In 1997 the IEEE 802.11 standard finalized for 2.4 GHz with 1 & 2Mbps. Then it move to 5 GHz and support up to 54 Mbps.

IEEE 802.15 is Bluetooth (wireless PAN)

IEEE 802.16 is the WiMAX (broadband wireless MAN)


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Future Wireless Networks

Present day research

Seamless connectivity

Mobile IP Universal mobility and high data rate access

4G systems with ATM access speed (over 100 Mbps) are underdevelopment

Almost all access to the Internet will become wireless!!


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Part II

Spectrum Analyzer

By

Hisham Alasady, PhD.


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Outline

Overview:

What is spectrum analysis? What measurements do we make?

Theory of Operation: Spectrum analyzer hardware

Specifications: Which are important and why?


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Overview

What is Spectrum Analysis?

8563ASPECTRUMANALYZER 9kHz -26.5GHz


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Overview

Types of Tests Made

.

Modulation

Distortion

Noise


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Overview

Frequency versus Time Domain

Amplitude

(power)

Time domainMeasurements

Frequency DomainMeasurements


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Overview

Different Types of Analyzers

Parallel filters measuredsimultaneously

LCD shows fullspectral display

A

ff1 f2

Fourier Analyzer


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Overview

Different Types of Analyzers

A

ff1 f2

Filter 'sweeps' over rangeof interest

LCD shows fullspectral display

Swept Analyzer


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Theory of Operation

Spectrum Analyzer Block Diagram

Pre-SelectorOr Low Pass

Filter

CrystalReference

LogAmp

RF input

attenuatormixer

IF filter detector

videofilterlocal

oscillator

sweep

generator

IF gain

Inputsignal

CRT display


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Theory of Operation

MixerMIXER

f sig

LOf

f sig LOf

LOf f sig- LOf f sig

+RFLO

IF

input


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IF FILTER

Display

InputSpectrum

IF Bandwidth

(RBW)

Theory of Operation

IF Filter


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Theory of Operation

Detector

DETECTOR

Negative detection: smallest value

in bin displayed

Positive detection: largest valuein bin displayed

Sample detection: last value in bindisplayed

"bins"

amplitude


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Theory of Operation

Video Filter

VIDEO

FILTER


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Theory of Operation

Other Components

LCD DISPLAY

SWEEPGEN

LO

IF GAIN

frequency

RF INPUTATTENUATOR


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Theory of Operation

How it all works together

3.6(GHz)

(GHz)

0 3 61 2 4 5

0 31 2

3 64 5

3.6

(GHz)0 31 2

fIF

Signal Range LO Range

fs

sweep generator

LO

LCD display

input

mixer

IF filter

detector

A

f

f LO

fs

fs

fs

fLO

-

f sf LO+

fLO

3.6 6.5

6.5


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Theory of Operation

Front Panel Operation


RF Input Numerickeypad

Control functions(RBW, sweep

time, VBW)

Primary functions(Frequency, Amplitude,

Span)

Softkeys


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Specifications


Frequency Range Accuracy: Frequency & Amplitude

Resolution Sensitivity Distortion Dynamic Range

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