Telemedicine: Core Technologies(Telecommunication and

Networking)

Jayanta Mukherjee

Signal Transmission

Transmitter ReceiverChannel

x(t)=A.sin.t)y(t.A.sin(.t

Channel Bandwidth

● How fast the system responds?

● Range of fequencies transmitted by the channel.

● Modulation is the process of translating signal's bandwidth into a channel's bandwidth.

Modulation

● Amplitude Modulation y(t)=A.x(t).sin(.t

● Frequency modulation y(t)=A.sin((k.x(t))t

● Phase modulation y(t)=A.sin(.t+k.x(t))

Telephone Line

● Bandwidth for local loop: 4 Khz● Bandwidth of voice signal: ~ 4 Khz● Analog Telephony does not require modulation

Modulation for Digital Communication

● Digital Data: Bi-level (0,1)● Frequency Shift Keying (FSK)● Phase Shift Keying (PSK)● QPSK● QAM● V.32 Modem: =2400 Hz., Number of levels=32

Data rate: 2400x6 bps=14.4 Kbps● V.90 Modem: Data rate: 57.6 Kbps (128 levels)

Quadrature Amplitude Modulation(QAM)

● Two carrier waves with quadrature phase shift A.x1(t).cos(t)+A.x2(t).sin(t)

● V.32 Modem: =2400 Hz., Number of levels=32 Data rate: 2400x6 bps=14.4 Kbps

● V.90 Modem: Data rate: 57.6 Kbps (128 levels)

Communication Channels

Communication Links

Terrestrial Wireless

POTS Leased lines ISDN LAN

SatelliteWirelessLAN

GSM/CDMA GPRS

Different Communication Links

Links Bandwidth

POTSISDN(BRI)

T-1 and fractional T-1DSL

Primary rate ISDNT-2 Leased linesT-3 leased linesT-4 leased linesBroadband ISDN

SONET

2.4 Kbps ~ 57.6 Kbps128 Kbps

384 Kbps ~ 1.54 Mbps128 Kbps ~ 9 Mbps

1.54 Mbps6.312 Mbps

46 Mbps273 Mbps

150 ~ 1200 Mbps51.84 ~ 4976 Mbps

16 kbps – 2 MbpsKu bandSkybridge

16 kbps – 64 MbpsKa bandTeledesic

155 MbpsKa band and 40-50 GHzCelestri

400 kbps – 30 MbpsKu, Ka bandCyberstarSatellite

2.4 kbpsL, Ka bandIridium

7.2 kbpsL, S, C bandGlobalstar

2.4 kbpsC, S bandICO

723.2 Mbps2.4 GHzBluetooth

54 Mbps5 GHzHiperlan2

20 Mbps5 GHzHiperlan1Wireless LAN

11 Mbps2.4 GHzIEEE 802.11b

20 Mbps5 GHzIEEE 802.11a

GPRS 171.2 kbps900/1800/1900 MHzGPRS

9.6 – 43.3 kbps1900 MHzGSM-1900

9.6 – 43.3 kbps1800 MHzGSM-1800GSM

9.6 – 43.3 kbps900 MHzGSM-900

Data Transfer Rates

Frequency BandSub-typeType

The main wireless communication networks/standards.

Different Wireless Communication Services

Links Bandwidth

GSMGPRS

Satellite

9.6 Kbps ~ 43.3 Kbps171.2 Kbps

2.4 Kbps ~ 155 Mbps

Computer Networking

● Connecting a group of computer for exchange of Information.

● Different roles of a computer Terminal Host Computer Acting like a telephone exchange

● Different Topology A grid of point to point connections Connected to a common channel (Bus) Ring Tree

Open system interconnection layers

Physical

Data link

Network

Transport

Session

Presentation

Application

……DNSSNMPHTTPSMTPTelnetFTP

UDPTCP

IP

Token RingATMEthernet

Basic signaling through media

Area of Coverage of Networking

● Local Area Networking (LAN) Organisation, Campus

● Wide Area Networking Distant locations

Data Rates Supported by Different LAN technologies

LAN Technology Datarate

EthernetToken ringToken bus

ATMGigabit Ethernet

10 Mbps4 ~ 16 Mbps

16 Mbps155 Mbps1000 Mbps

A predefined circuit width dedicated bandwidth for end to endcommunication is set before the transfer of data.

Circuit Switch

•Predefined•Full Bandwidth Used

Pay LoadDST 1Src 1 Pay LoadDST 2Src 2

RouterTo

DST

1AC

K To

Src

1 ACK To Src 2To DST 2

Packet Switching

Virtual Circuit

Dynamic Allocation of connected links with shared B.W.

A AA

B B B

B BAA A

BB

B

AAA

BB

A AA

BB

Permanent Virtual Circuit

Predefined Virtual Circuit with shared B.W.

B

A A

BB B B B

AA

Packets of fixed size are transmitted at constant rate (irrespective of availabilityof data for transmission).

Cell Switching

Header Pay Load

< 5 bytes >< 48 bytes >ATM Cell

Connectionless Services

No defined path for packet transmission.

Packet travels and ones it reaches destination, it is accepted by the process.

Users

Network Resources

Communication Channel

User ID & Password Authentification

Firewall Encryption

Log in restriction

Network Security

Encryption Alg

Encryption Alg Decryption Alg

Decryption Alg Plain text

Plain text

Plain text

Plain text

Cipher text

Cipher text

Private KeySender Receiver

Public Key Public Key

Sender Receiver

Private Key Cryptography

Public Private Key cryptography