Date post: | 13-Aug-2015 |
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Definition
An umbrella term that includes any communication device or application.
Right from the Bluetooth to Wi-Fi LANs and MANs to the satellite communication, the wireless networks hold these on.
Wide spread applications and services- video conferencing, telemedicine, distance learning, and much more.
Types of wireless technologies
Wireless LANs (WiFi)– 802.11 standards – Mobility support
Wireless MANs (WiMaX)– 802.16 standard
Wireless Networks Difference from wired Mobility
RF Basics Frequency, modulation Medium access control
WiFi Overview Basic elements Standards and variants
WiMaX Overview Basic elements
Wireless v/s Wired networks
• Regulations of frequencies– Limited availability, coordination is required– useful frequencies are almost all occupied
• Bandwidth and delays– Low transmission rates
• few Kbits/s to some Mbit/s.– Higher delays
• several hundred milliseconds– Higher loss rates
• susceptible to interference, e.g., engines, lightning
• Always shared medium– Lower security, simpler active attacking– radio interface accessible for everyone– secure access mechanisms important
CDMA
Code Division Multiple Access.Uses spread spectrum techniques.Data is sent in small pieces over a number of
discrete frequencies.Unique spreading code.Greatest advantage- doesn’t assign a single
frequency to user. Secured transmission.
Introductory
A wireless technology standard for exchanging data over short distances. Any data or information can be transmitted faster and with a high speed.
Using short-wavelength UHF radio waves in the ISM band from 2.4 to 2.485 GHz.
The IEEE standardized Bluetooth as IEEE 802.15.1.
History
1994: Ericsson mobile communication Ltd. Started project named “Bluetooth”.
1998: Bluetooth SIG formed.1999: Bluetooth 1.0, Bluetooth 1.0B
specification release.2000: Bluetooth headset release, first
consumer product.2003: Bluetooth 1.2 released.
Piconets and ScatternetsThe basic unit of networking in Bluetooth is a piconet, consisting of a master and from one to seven active slave devices.
A piconet is a computer network which links a wireless user group of devices using Bluetooth technology protocols. A piconet consists of two or more devices occupying the same physical channel (synchronized to a common clock and hopping sequence).
The advantage of the piconet/scatternet scheme is that it allows many devices to share the same physical area and make efficient use of the bandwidth.
Bluetooth communication
Bluetooth uses a radio technology called frequency-hopping spread spectrum.
Bluetooth is a packet
based protocol with a master-slave structure.
Bluetooth Versions
Versions 1.0 and 1.0B had many problems, and manufacturers had difficulty making their products interoperable.
Bluetooth v1.1 Bluetooth v1.2 Bluetooth v2.0 + EDR Bluetooth v2.1 + EDR Bluetooth v3.0 + HS Bluetooth v4.0 Bluetooth v4.1 Bluetooth v4.2
General application
Connection to your PC or notebook to printers, scanners and faxes.
Automatic Message Delivery. Home Automation. Have automatic synchronization of your desktop. IBM researchers are working on a number of
personal devices like a WatchPad that could be connected with other devices through Bluetooth.
Application in Telemedicine
Telemedicine is a rapidly developing technology of clinical medicine where medical information is transferred via wireless communication technology.
Embedded system that uses the short-range Bluetooth wireless networking protocol to connect patient data to the network and then on to the healthcare provider. This avoids the problem of trying to ensure that a viable connection between monitoring devices and the internet or cellular phone network is maintained constantly.
ECG Telemetry
The newest Bluetooth technology was added to collect the short and long term digitize ECGs with relevant clinical data to monitor a patient.
GPRSWhat is GPRS?General Packet Radio Service is a packet based wireless communication service that permits data rates from 56 kbps and 114 kbps and continuous connection to the Internet for mobile phone and computer users.
• GPRS was standardized by European Telecommunication Standard Institute(ETSI).
• Generally, GPRS is a packet oriented mobile data service on the 2G and 3G cellular communication system.
• GPRS is based on Global System for Mobile Communication(GSM) and existing services such as SMS.
Generation:
• Each generation of data network gets faster. We saw 2G (second generation) from 1999, 3G (third generation) from 2001 and started seeing 4G (fourth generation) in 2012.
• GPRS,2G,3G,4G are all indicators of signal strength for downloading and uploading data.
GPRS services:
• Wireless Application Protocol (WAP) access.• Short Message Service (SMS).• Multimedia Messaging Service (MMS).• Internet communication services such as
email and world wide web (www) access.
GPRS features
• Mobility – to maintain constant voice and data communication.
• Immediacy – to maintain connectivity when needed.
• Localization – to obtain information relevant to their current location.
• Communication – to obtain E-mails, fax, messaging and internet access etc.
Introductory Wireless Technology is an alternative to Wired
Technology which is commonly used for connecting devices in wireless mode.
Wi-Fi (Wireless Fidelity) is a generic term that refers to IEEE 802.11 standard for Wireless Local Area Networks (WLANs).
Wi-Fi Network connect computers to each other, to the internet and to the wired network.
The Wi-Fi Technology
Wi-Fi Networks use Radio Technologies to transmit and receive data at high speed:
IEEE 802.11b IEEE 802.11a IEEE 802.11g
Elements of a WI-FI Network
Access Point (AP) - The AP is a wireless LAN transceiver or “base station” that can connect one or many wireless devices simultaneously to the Internet.
Wi-Fi cards - They accept the wireless signal and relay information. They can be internal and external.
Safeguards - Firewalls and anti-virus software protect networks from uninvited users and keep information secure.
Infrastructure network
The client communicate through Access Point.
Any communication has to go through AP.
If a Mobile Station (MS), like a computer, a PDA, or a phone, wants to communicate with another MS, it needs to send the information to AP first, then AP sends it to the destination MS.
How a Wi-Fi Network Works
A Wi-Fi hotspot is created by installing an access point to an internet connection.
An access point acts as a base station. When Wi-Fi enabled device encounters a hotspot
the device can then connect to that network wirelessly.
A single access point can support up to 30 users and can function within a range of 100 – 150 feet indoors and up to 300 feet outdoors.
Many access points can be connected to each other via Ethernet cables to create a single large network.
Application of Wi-Fi
Many electronic devices use Wi-Fi due to its simple functions.
Companies use Wi-Fi to create wireless networks within their company.
Phone companies such as use Wi-Fi Hot Spots for their users to get free calling/internet access.
Gaming companies like Nintendo use Wi-Fi to synch their products and to use global network usage
Application in Telemedicine
Health care centers in developing countries are not equally accessible to people living in cities and those living in less developed and distant areas.
Health technicians often need to communicate with their reference centers for consultation or coordination of medical emergencies that they can not handle by themselves.
WiFi networks composed of long distance point-to-point links and medium distance point-to-multipoint infrastructures allow an easy deployment of low-cost wireless broadband networks in rural areas.
Advantages
Mobility Ease of Installation Flexibility Cost Reliability Security Use unlicensed part of the radio spectrum Roaming Speed
GSM
Stands for Global System For Mobile Communication
It is a digital mobile telephony system
Developed as a replacement for first generation cellular network
Base station subsystemResponsible for handling traffic and signaling between a
mobile phone and the network switching subsystem.Base transceiver station contains equipment for
transmitting and receiving signals and equipment for encrypting and decrypting communications with the Base station controller.
BSC have tens or even hundreds of BTS under its control.
Transcoder is responsible for transcoding the voice channel coding between the coding used in the mobile network, and the coding used by PSTN.
Packet control unit is late addition to the GSM standard and it performs some of the processing tasks of the BSC, but for packet data.
General applications
Monitoring of the farming area and collecting field data such as temperature, humidity, wind speed, and pest/insect captured numbers
Online monitoring of the earth-pole system
Document identification in a library system
Applications in telemedicine
Telepharmacy • Helps to get
medicines to remote areas
ECG ,EEG and EMG
telemetry
• helps in patient monitoring without actually hospitalizing