telemedicine: core technologies (telecommunication and networking) jayanta mukherjee
TRANSCRIPT
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