1. Lecture 1: Communication Networks and
Services
Md Arafat Hossain
Department of Electrical and Electronic Engineering, Khulna University of Engineering and Technology, Khulna, BANGLADESH

2. Introduction What is a communication networks?
A communication network (or simply network) consists of an interconnection of a number of routers made up of intelligent processors.
Route data through the network
Serve as a shared resource
Efficient data exchange
Provide framework to support new application and services
Purposes

3. Different types wireless networks
Some commonly used networks in telemedicine applications and explain why they are suitable for specific situations
Bluetooth IR
Wi-Fi
ZigBee
Cellular Networks
WiMAX (fixed)
LMDS

4. Different types wireless networks
Invented in 1994 by Ericsson. Later developed with a larger company Bluetooth Special Interests Group, or "SIG.
Provides short range coverage primarily for mobile devices connected in an ad hoc network called ‘piconet’ within a room.
Bluetooth operates at frequencies between 2402 and 2480 MHz, or 2400 and  MHz including guard bands 2 MHz wide at the bottom end and 3.5 MHz wide at the top.
 IEEE standardized Bluetooth as IEEE , but no longer maintains the standard. The Bluetooth SIG oversees development of the specification, manages the qualification program, and protects the trademarks.
Bluetooth
Bluetooth divides transmitted data into packets, and transmits each packet on one of 79 designated Bluetooth channels(Each channel 1 MHz). Bluetooth Low Energy uses 2 MHz spacing, which accommodates 40 channels

5. Different types wireless networks
Useful for small
wearable biosensors due to low power
Bluetooth applications
Bluetooth mobile phone headset
notebook internal Bluetooth card 
CMS50D-BT Bluetooth Pulse Oximeter [2]
Bluetooth USB dongle
Key selling points are low cost requiring simple circuitry and low power consumption.
[2] Contec Cms50d-Bt FDA Telemedicine Finger Pluse Bluetooth APP Fingertip SpO2 Oximeter

6. Different types wireless networks
Bluetooth 1.1
Ratified as IEEE Standard (2002)
Received Signal Strength Indicator (RSSI)
Bluetooth 1.2
Faster connection
Adaptive frequency-hopping spread spectrum
Higher transmission speeds (721 kbps)
Extended Synchronous Connections (eSCO),
Bluetooth EDR  (2004)
Enhanced Data Rate (EDR) for faster data transfer (3 Mbps) 
Bluetooth EDR (2007)
Secure simple pairing (SSP): this improves the pairing experience for Bluetooth devices
[1]

7. Different types wireless networks
Bluetooth HS (2009)
Data transfer speeds of up to 24 Mbps (theoretically)
Bluetooth LE (2010)
Includes Classic Bluetooth, Bluetooth high speed and Bluetooth Low Energy (BLE) protocols
Bluetooth 4.1 (2013)
An incremental software update: Increased co-existence support for LTE, bulk data exchange etc.
Bluetooth 4.2 (2014)
Introduces features for the IoT: Low Energy Secure Connection, Link Layer Privacy, Internet Protocol Support Profile (IPSP)
Bluetooth 5 (2016) (“NOT 5.0”)
Bluetooth 5 provides, for BLE, options that can double the speed (2 Mbps burst) at the expense of range, or up to fourfold the range at the expense of data rate, and eightfold the data broadcasting capacity of transmissions, by increasing the packet lengths
Few example device: Samsung Galaxy S8, iPhone 8, 8 Plus, iPhone X
[1]

8. Different types wireless networks
Infra-red (IR)
IR transmitter
IR receiver Si
Regulated by Infrared Data Association (IrDA):
Can not penetrate through wall
Name
λ (μm)
Data rate
T (ºK)
IrDA-NIR
(0.7-1) to 5
115 Kbps
740 to (3,000-5,200)
IrDA-MIR
5 to (25-40)
1.15 Mbps
( ) to 740
IrDA-FIR
(25-40) to ( )
4 Mbps
( ) to ( )
near-infrared or IR-A is used in night vision applications
wireless communications usually use short-wavelength infrared (IR-B). .. long range optical communications

9. Different types wireless networks
Infra-red (IR)
IR transmitter
IR receiver Si
Can not penetrate through wall
Requires direct LOS and the transmitter must be aligned fairly close to the centre of the sensor with only +/- 15º offset possible
Although current IrDA compatible devices support only up to 16 Mbps, the introduction of Giga-IR offers a
theoretical speed of up to 1 Gbps. It is often used in small ECG fragment transmission.

10. Network connectivity to the legacy wired LAN
Different types wireless networks
Wireless Local Area Network (WLAN) and WiFi
Unlike Bluetooth and IR, WLAN requires some efforts in setting up initial configurations before a communication link can be established.
Network connectivity to the legacy wired LAN
Desktop
with PCI LAN card
Laptop
with PCMCIA LAN card
Access Point
Mobile
Provides network connectivity over wireless media
An Access Point (AP) is installed to act as Bridge between Wireless and Wired Network
The AP is connected to wired network and is equipped with antennae to provide wireless connectivity

11. Range (Distance between Access Point and WLAN client) depends on structural hindrances and RF gain of the antenna at the Access Point. So varies for indoor or outdoor operation 50 to 300 m.
To service larger areas, multiple APs may be installed with a 20-30% overlap
A client is always associated with one AP and when the client moves closer to another AP, it associates with the new AP (Hand-Off)
Three flavors: based on the specifications for PHY & MAC layer
802.11b (1, 2, 5.5 and 11 Mbps data rates in the 2.4 GHz ISM)
802.11a (54 5 GHz UNII band )
802.11g (54 Mbps on the 2.4 GHz band)
PHY: how raw data bits are transmitted over the air
MAC: Provides addressing and channel access control procedures that allow several devices to communicate with a single Access Point

12. Different types wireless networks
ZigBee
Small digital devices for WPAN complying IEEE
Easy to implement and very low power consumption, low cost (transreceiver less than 1 U$)
Primarily used for wireless data controlling and monitoring
No global standard for operating f, 686 MHz (Europe), 915 MHz (USA), 950 MHz (Japan) and 2.4 GHz (other parts if the world)
Regularly used in safety devices e.g. smoke detector, air con control etc, Also used in BAN.
Communication Net can be served with ZigBee Co-cordinator and effective used to relay data between device

13. Different types wireless networks
Cellular Networks
The mobile phone network we are using everyday

14. Cellular Networks

15. Broadband Wireless Access (BWA)
Provides high speed wireless Internet access or computer networking access over a wide area. The term comprises both fixed and mobile broadband.
Broadband: download >25 Mbits and upload >3 Mbits (FCC)
Ultra high speed – support diverse variety of services
fc can be few GHz to 40 GHz (depends on the local regulation )
Technologies used include Local Multipoint Distribution Service (LMDS) and Multichannel Multipoint Distribution Service (MMDS), as well as heavy use of the industrial, scientific and medical (ISM) radio bands and one particular access technology was standardized by IEEE , with products known as WiMAX
LMDS is a prevalent WBA development, can support data over 512 Mbps.
The properties of LMDS make it particularly suited for telemedicine backbone support.
main trunk line for interconnecting different LANs as well as equipment together over a large area

16. Different types wireless networks
Satellite Network
Comsat (communication satellite) serve as a point-to-point microwave radio relay that provides a radio link between two earth sations.
Used in Wide Area Network (WAN)
Very reliable and high speed comm link – suitable for remote robotic surgery

17. Different types wireless networks
Licensed and unlicensed frequency bands
Some net operates in licensed band while many others operates in unlicensed band and share with many users.
How they can affect in telemedicine?
No implementation delay and cost in unlicensed band. Accessed by many devices so stay at a risk of security braches and interference.
Unlicensed Vs
Interference protection and guaranteed bandwidth availability in licensed band.
Licensed

18. Comparison: Different types wireless networks