DLRL 1 Workshop

8/3/2019 DLRL 1 Workshop

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WORKSHOP ON EMERGING TRENDS IN TECHNOLOGIES FOR

WLANS, WPANS, HANS, UWBS, MOBILE SATELLITE PHONE

SERVICES & 4G CELLULAR SYSTEMS

ORGANISED JOINTLYBY

BHARAT INSTITUTE OF ENGG., & TECHNOLOGYMANGANPALLY, RANGAREDDY DISTRICT

AND

DEFENCE RESEARCH & DEVELOPMENT ORGANISATION

DLRL-ELSEC Hyderabad Ministry of Defence

Evolution of wireless technologies

ByProf.G.Kumaraswamy Rao

HOD ECE Dept. BIET

(Former Director DLRL)

Date: 29th August 2011 Venue: ELSEC-DLRL


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What is Communication?

- Exchange of i) Voice ii) Data iii) Video from one pointto another .

- Medium for communicationa) Wired - i) Copper (Cable, TP)

ii) Fibre Optics

b) Wireless - i) R.F.

ii) I.R.


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WIRELESS SIGNIFICANCE

Wireless communication technologyhas a huge impact onmost of developed world and a large number of developingcountries.

Wireless Communication is affecting almost every aspect ofour daily lives.


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What is Wireless Communication??

All types of devices that are not connected by a wire butstill interface with each other

Examples of Wireless:1. Garage door opener

2. Television remote control

3. Pager

4. Cell phone

5. Cordless phone

Another meaning of Wireless:- transmission of data without wires

Ex: 1. e mail messages

2. Spread sheets

3. Telephone voice messages


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USES OF WIRELESS TECHNOLOGIES

Voice/Data can be sent or received.

Browse the Internet.

Access corporate databases from any location in the

world.Devices like PCs, digital cameras, laser printers,

scanners,

and other office equipment can communicate with each

otherRefrigerators, A/Cs, heaters, microwave ovens, water

heaters or any other household item can be controlledremotely by using wireless remotely.


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WIRELESS COMMUNICATIONS:TRENDS & CHALLENGES

High Data Rate Services

High spectral efficiency

Advancement to 3G and beyond communication to

improve data rate.Ex. i) ECDMA based DS-CDMA direct spread with FDD

ii) CDMA 2000 multi carrier CDMA

iii) TDD-CDMA Time Division Duplex

MIMO Multiple Input Multiple OutputUWB - Ultra wideband cross-layer design


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WIRELESS COMMUNICATION BASICS

Quality of Digital transmission:

1. Speed or bits/second

2. Bit Error Rate BER

BER is the percentage of bits are in error by the time itreaches the receiver

Good transmission ensures 0.0001 to 0.0002 percent

(1 to 2 bits in 106

bits)


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LAWS OF COMMUNICATION

NQUIST RATE (1928)fp 2B where fp = Number of independent pulses per

sec.B = Bandwidth HZ

HARTLEYS LAWR 2B Log2 (M)

where R = Number of bits per sec.M = Number of signal levels in a symbol

SHANNONS THEOREMR B Log2 (1+SNR)

where SNR = Signal to Noise Ratio


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EXAMPLE:

i) Channel Bandwidth = 1 MHZ

ii) SNR = 63

Max. channel capacity = C = B log2 (P+SNR)= 106 log2 (1+63) = 6MBps

Using Nquist to get Signal

Levels

C = 2B log2 2n

6 x 106 = 2x1x106xlog22n


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TYPES OF NETWORKS

LAN (Local Area Network) 500 Mts MAN (Metropolitan Area Network) 50 KM WAN (Wide Area Network) > 50 KMs to 250 KMs.

NETWORK TOPOLOGIESi. Bus topologyii. Star topologyiii. Ring topologyiv. Mesh topology


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NETWORK SWITCHING

i) CIRCUIT SWITCHING:

SWITCHING OFFICE

TELEPHONE

TELEPHONE

There is a physical connection between transmitter & receiver until the call isterminated


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ii) PACKET SWITCHING

Bursty data transmission.

Individual packets forwarded need not take the same path.Congestion/Collission of packets takes place.

iii) MESSAGE SWITCHING

Ex: Telegraph Message

1 2

Packet 1

Packet 1

Packet 2

Packet 2

Packet 2

Station Station


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MULTIPLE ACCESS

To share the limited number of channels simultaneously by

many mobile users, multiple access techniques are used.

1) Frequency Division Multiple Access (FDMA)

2) Time Division Multiple Access (TDMA)

3) Code Division Multiple Access (CDMA)

FDMA

- Individual channels are assigned to users.

- FDD Frequency Division Duplex.- Two (2) distinct frequencies are allotted for every user

i) forward channel ii) reverse channel called FDD.


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TIME DIVISION MULTIPLE ACCESS

TDMA:- Time slots are allotted to each user.

- All users use the same frequency.

- Frequency Duplexers not required.- Time synchronization required.

- Each Frame has preamble, information and trial bits.


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SPREAD SPECTRUM MULTIPLE ACCESS(SSMA)

Spreads the information over a bandwidth severalorders of magnitude wider than the information.

Spreading sequence (code) should be known torecipient

Types of SSMA:

i) Frequencyhopping

ii) Direct Sequence also called CDMA.


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WHY WIRELESS?

1. Mobility: Freedom to move without tethered by wires

Ex: Police Officers, travelling persons, inventory clerks2. Easier & Less Expensive:

- Cabling in existing building difficult, cumbersome &

expensive

- Cabling in historical bldgs. spoils the aesthetic valueof the premises

- Installation time consumed is more and disturbs existingwork.

3. Increased reliability

- Cable breakages, loose connection in connectors etc.

avoided.

4. Disaster events (Accidents, fires, tornadoes, tsunamies)

- Quickly devices can be configured on adhoc basis.


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WIRELESS APPLICATIONS

i) Education: E class room

ii) Home Entertainment: Control of lights, air-conditioning,

refrigerators, washing machines, PCs, scanners, printers

etc.

iii) Health Care: Consultations with specialists doctors.

iv) Government: Monitor municipal vehicles, despatch of

work crews in emergencies.

v) Military: Soldiers at any place can access data bases,

access internet.


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vi) Office Environment: Every employee have access to office

database.

- Expensive cabling is avoided.

- Adhoc office environment can be created in a very

short period.

- Costly resources like colour printers, scanners etc.

can be shared.

vii) Warehouse Environment: Inventory of the goods

maintained.

- Update of stock and shortage.viii) Industrial Control: Various places in a large workshop

where wires cannot be installed, connected by wireless.


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DISADVANTAGES OF WIRELESS

Radio Signal Interferencesi. from signals from own system

ii. from signals of other deviceiii. microwave ovens

iv. elevator motors

v. heavy electrical equipment

Bandwidth limitations in the spectrum Security is low since signals are transmitted in air


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WIRELESS TYPES

Types of Wireless:

i) Fixed - Ex: Microwave Towers

ii) Low Mobility Pedestrian

iii) High Mobility Vehicle at 150 KMPH iv) Satellites

Types of Wireless:

i) Personal Area Network (PAN)

ii) Wireless LAN a) Low rate b) High rate

iii) Wireless MAN

iv) Wide Area a) Wide Area LAN

b) Cellular


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WIRELESS TECHNOLOGIES

i. Blue toothii. Ultra wide bandiii. Satelliteiv. Cellularv. Wireless LANvi. Fixed broad band

vii. Wireless WAN


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WIRELESS DATA COMMUNICATION TECHNOLOGIES

Wireless Technology Transmission Distance Speed

RFID 2.5 cms to 100 mts a few KBPS

Blue Tooth 10 mts 1 mbps

UWB 50 mts 100 mbps

WLAN 802.11b

WLAN 802.11g

110 mts

90 mts

11 mbps

54 mbps

WMAN 802.16 Wi Max 56 Kms 75 mbps

2G Digital Cellular

2.5G Digital Cellular

3.5G Digital Cellular

Nation wide

Nation wide

Nation wide

-

384 kbps

2 mbps

Satellite World wide 250 msecs delay


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VISION OF AN IDEAL WIRELESSNETWORK/DEVICE - 1

REAL-TIME VIDEO:

- Data rates high

- Delay constraint like in voice

TECHNICAL ISSUES:

- Devices small, light weight, hand held, cheap, multiple

mode to support i) Voice ii) Image iii) Text iv) Video

data

- Battery small, Recharge interval large

- Place all power intensive software on fixed sites

GEO LOCATION:

- Locate user any where in the globe in short time

INTER CONNECTIVITY:

- With PSTN, satellite network, submarine cable, internet.


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COVERAGE:

i) In building ii) Campus iii) City iv) Regional v) Global

SUPPORT:

- Voice Systems: - Low Data Rate 20 KBPS

- BER < 10-3

- Delay < 100 ms

- Data Systems: - Data Rates 1-100 MBPS

- BER < 10-8 Retransmission of

Error Data

- No restriction on delay


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RADIO SPECTRUM:- Frequency spectrum is scarce resource, so very

expensive

- Licenses to use spectrum are auctioned (GSM gave

4,50,000 crores).- Use of high frequency give more bandwidth.

Equipment Cost more and range limited because of

attenuation and puts loss.

MOBILITY:

- Terminals moving at 200 KMPH should be located and interfaced.

- Without subscriber knowing, seamless transfer from one cell to

another or standard.

SECURITY:

- Concern area for wireless proper encryption.


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CELLULAR NETWORKS

Network is built around a low power transmitters.

Each cell has a small geographical area handlesnumber of users.

Many transmitter towers are spread throughout thegeographical area.

Same R.F. Channels can be used by another towerlocated a few kilometers away to avoid interference.

This concept maximizes the use of limited bandwidth.


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MTSOPSTN

B.S.

BaseStation

MTSO Mobile Telephone

Switching Office

PSTN-PublicSwitchedTelephone

Network

CELLULAR NETWORK


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1G FIRST GENERATION CELLULARNETWORK

First Cellular System deployed in Norway - 1981.

Voice transmission.

Analog Modulation FM-FDMA.

Advanced Mobile Phone System (AMPS) in NorthAmerica 1983

7 cell reuse.

25 MHZ band in uplink from 824-849 MHZ.

832 channels. Channel spacing 30 KHZ.

Circuit switched technology.


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2G CELLULAR NETWORK

Uses TDMA (GSM) or CDMA

Supports roaming between network operators/differentcountries.

Supports circuit-switched voice communication.

Supports mobile data.Supports internet services.

Standards IS-136(USA) TDMA; IS-95(USA+Korea)CDMA; GSM TDM (Europe+India)

Data Rates 9.6 KBPS.GSM supports 8 time slots (users). Each slot has 200

KHZ.

GSM 935-960 MHZ & 890-915 MHZ.


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2.5G CELLULAR NETWORKS (GPRS)

Standards 1. General Packet Radio Services (GPRS).

Packet Switched Network.

Data Rate 21.4 KBPS.

If all 8 time slots are used consecutively, data rate 171.2KBPS.

Each user provide their own error correction scheme.

Supports circuit switched voice transmission.

Supports packet switched data transmission.


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2.5G CELLULAR NETWORKS (EDGE & HSCD)

Standards 2. Enhanced Data Rates for GSM Evolution(EDGE).

Uses Octal phase shift keying 8-PSK.

Data rate 547.2 KBPS. BUT RESTRICTED TO 384 KBPS.

Standard 3. HSCD High Speed Circuit Switched Data.

Allows a single mobile user to use consecutive time slots.

Original 2.5G allows 21.4 KBPS Increases to 57.6KBPS.


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3G CELLULAR NETWORKS

2G Systems support data over voice paths. Speeds arelow 9.6 KBPS to 14.4 KBPS.

1980 Planning for 3 G started.

Goal of 3G : i) Merge all standards into one.

ii) Internet Access. 3G phones require quintuple mode

i) 800/900 MHZ band

ii) 1.7 to 1.9 GHZ band

iii) 2.5 to 2.69 GHZ band

Consensus is for

i) 5 different Radio standards

ii) 3 different frequency bands.


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3G CELLULAR NETWORKS

NECESSITY FOR 3G- All 2G Systems are Voice Centric.

- GSM supports SMS, Text messages upto 160

characters

- 2G Data Speeds low 9.6 or 14.4 KBPS.- Planning for 3G started 1980.

GOAL OF 3G

- Worldwide Roaming Connectivity instead multimode

mobile.- Increase of Data Rate 144 KBPS for fast moving

vehicles

- 2 MBPS for stationary mobile.


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3G STANDARDS

PRESENT STANDARDS

Frequency: i) 800/900MHZ ii) 1.7 to 1.9GHZ iii) 2.5 to2.69 GHZ.

GSM USERS: i) W-CDMA ii) TD-SCDMA (CHINA)

CDMA USERS CDMA 2000

UMTS Universal Mobile Communication System group.

Backward compatibility with GSM, IS-136 & PDC TDMA

Support 2.048 MBPS.

Spectrum 5 MHZ.


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3G-W-CDMA

UMTS Universal Mobile Communication System group.

Backward compatibility with GSM, IS-136 & PDC TDMA.

Support 2.048 MBPS.

Spectrum 5 MHZ.

Uses Direct Sequence Spread Spectrum DS-SS.

High quality data, multimedia, streaming video, audio,

broadcast services. 6 times increase in spectral efficiency over GSM.

Cell phone Tri-mode i) 2G TDMA ii) EDGE iii) W-CDMA


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3G-CDMA 2000

Seamless support to 2 and 2.5G CDMA users (IS-95,IS-95A, IS-95B).

3G PP2 working developed this technology.

Each channel bandwidth 1.25 MHZ.

CDMA 2000 1 x means single carrier is used.

CDMA 2000 3 x RTT uses 3 adjacent 1.25 MHZ channels.

Adjacent channels combined to get super channel 3.75MHZ.

Less expensive upgrade than W-CDMA technology.


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3G TD-SCDMA

Most popular in China.

Time Division Synchronous Code Division MultipleAccess.

Radio channel is 1.6 MHZ.

5 M secs. Frame divided into 7 time slots.

Number of slots allotted to user depending on data rate.

For subscriber downloading data, require more numberof time slots than reverse channel.

SCDMA is more efficient.


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MIGRATING TO 4G

GOAL:

Integrate every wireless standard.

Seamless adaptability to multiple wireless standards.

Auto reconfiguration by downloading configurationsoftware.

Smooth handoff between cells of different standards.

Ubiquitous available at any time and at any place.

Service transparency in billing.


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DIFFERENT STANDARDS IN MOBILECOMMUNICATIONS

Technology 1G 2G 2.5G 3G 4G

Year of

idea

1970 1980 1985 1990 2000

Implementation 1984 1991 1999 2002 2012??

Service AnalogVoice

DigitalVoice

Packetized Broadband2mbps

IP

oriented

Multiple Access FDMA TDMACDMA

TDMACDMA

CDMA -

Data Speed 1.9KBPS

14.4 kbps 384 KBPS 2 MBPS 200 MBPS


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SATELLITE COMMUNICATIONS

Satellites LEO 2000 KMS altitude.

MEO 9000 KMS altitude.

GEO 35786 KMS altitude.

Satellite provide communication to remote areas wherecellular telephones or landlines becomes uneconomical.

Covers large area because of height advantage.

Provides high availability, reliability and quality etc.

Satellites are used for i) Broadcast of entertainment TVchannels ii) Digital Radio iii) Telecommunication.


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SATELLITE EARTH STATION


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SATELLITE NETWORK

Mobile Satellite services


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Mobile Satellite services

Why LEOs/MEOs ARE preferred to GEO?

*GEO propagation is 0.25 sec. not attractivefor voice

*Propagation Loss {4R/}2 So GEO not preferred

*LEO are about 1850 Kms. Altitude*Operating Frequency 2 GHz. (Low preferred because of

{4R/}2

*In present technology 2400 Bps enough for toll qualityvoice communication

*Omni antenna required for hand held mobile phone


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Characteristics of MSS

Low delay in voice transmission

LEO have orbital eriods of 1.5 to 10 hours

High inclination angles appear overheadtwice a day

3 basic types

i) Non voice little LEOS

ii) Full service LEOSiii) Broad band LEOS


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LITTLE LEOS

Support 100 to 300 Bps

Frequency below 1GHs

Store and forward box in sky

Ex: ORB comm.

-Messagimg ,Emergency

-36 satellites

-VHF -148- 150.5 MGHs Uplink-137-138 MGHz Downlink

-handheld devices Rs.4500 to 22500

-operaional 1995


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BIG LEO

Ex: i)Irridium (Motorola)

ii) Loral

iii) Global Star (Qualcomm)

iv) Oddyssey (TRW)

Objectives 1. Voice and data

2.Frequency between 1 and 3 GHz

3.Processing transponder4.Packet oriented

5.Error detection and correction


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WIRELESS LANDSCAPE


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THANK YOU

DLRL 1 Workshop

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