LAB NO - 1
FAMILIARIZING WITH EXISTING AND EVOLVING WIRELESS COMMUNICATION TECHNIQUES
HISTORY -
The first wireless network were developed in the pre-industrial age.These system transmitted information over line of right distances using signalling,flashing,mirrors,signal flares.
These early communication networks were replaced first by telegraph network and later by telephone.
In 1895, few decades after, the first radio transmission from the Isle of Wight is to a tugboat 18 miles away, and radio communication was born. Radio technology advanced rapidly to enable transmissions over large distance with better quality, less power and smaller, thereby enabling public and private radio communication, television and wireless networking.
Pocket radio network trend commercial application in supporting wireless data services in 1990's ,enable wireless data access at fairly 1000 speeds on the order of 20 kbps.These services mostly disappeared on the 1990's due to low data rates and high cost and supplanted by the wireless data capabilities of cellular telephones and wireless local area networks (LANs).
The introduction of ethernet technology (10 Mbps data rate) in the 1970's started many commercial companies away from radio based networking.
Initial wireless LANs had very poor performance in terms of data rates coverage, security, lack of standardization and high cost resulted in weak sales.
Current generation of wireless LANs, based on the family of IEEE 802.11 standards, have better performance, but data rates are low and the coverage are in still small wired ethernet offers data rates of 100 mbps. Despite this wireless LAN are performed in homes, offices due to their convenience and freedom from wires.
The challenge for future wireless LANs will support many users simultaneously with bandwidth intensive and delay constrained applications such as video.
Successful application of wireless networking has been the cellular telephone system in 1915 but it has capacity problem. In late 1980, there is no more demand for cellular service ,the development of digit cellular technology for increased capacity and better performance became essential.
The second generation of cellular system based on digital communication having higher capacity improved cost speed and power efficiency of digital hardware and gradually evolved to support data services such as email, internet access and short messaging.
In 1963, first GEO satellite launched, geosynchronous satellite have large coverage areas require great deal of power to reach satellite and propagation delay in too large and these disadvantage caused a shift in 1990's towards lower orbit satellites.
CURRENT-
Frequency reuse.
The introduction of ethernet technology (10 Mbps data rate) in the 1970's started many commercial companies away from radio based networking.
Initial wireless LANs had very poor performance in terms of data rates coverage, security, lack of standardization and high cost resulted in weak sales.
Current generation of wireless LANs, based on the family of IEEE 802.11 standards, have better performance, but data rates are low and the coverage are in still small wired ethernet offers data rates of 100 mbps. Despite this wireless LAN are performed in homes, offices due to their convenience and freedom from wires.
The challenge for future wireless LANs will support many users simultaneously with bandwidth intensive and delay constrained applications such as video.
Successful application of wireless networking has been the cellular telephone system in 1915 but it has capacity problem. In late 1980, there is no more demand for cellular service ,the development of digit cellular technology for increased capacity and better performance became essential.
The second generation of cellular system based on digital communication having higher capacity improved cost speed and power efficiency of digital hardware and gradually evolved to support data services such as email, internet access and short messaging.
In 1963, first GEO satellite launched, geosynchronous satellite have large coverage areas require great deal of power to reach satellite and propagation delay in too large and these disadvantage caused a shift in 1990's towards lower orbit satellites.
CURRENT-
- CELLULAR TELEPHONE SYSTEMS -
Frequency reuse.
- First generation (1G) called advance mobile phone service (AMPS) used FDMA.
- Second generation(2G) called GSM used combination of TDMA and slow frequency hopping with frequency shift keying for the voice modulation.
- Third generation (3G) based on WCDMA.
2. CORDLESS PHONE-
Designed to provide a low cost low mobility wireless connection to the PSTN that is, a short wireless link to replace the cord connecting a telephone base unit and its handset.
3. WIRELESS LAN-
It provide high speed data within a small region as users move from place to place.
4. WIDE AREA WIRELESS DATA SERVICES-
It provide wireless data to high mobility users once a large coverage area.
5. BROADBAND WIRELESS ACCESS-
It provides high rate wireless communications between a fixed access point and multiple terminals.
6. PAGING SYSTEM-
Paging system broadcast a short paging message simultaneously from many tall base stations at very high power.
7. SATELLITE NETWORKS-
Appealing use is broadcasting of video and audio over large geographic regions, the cost of the system can be amortized over many years making service quite competitive.
8. LOWER COST LOWER POWER RADIO : Bluetooth and Zig bee
Bluetooth radio provide short range connections between wireless device along with rudimentary networking capabilities.
Zigbee radio specification is designed for lower cost and power.
9. ULTRAWIDEBAND RADIO -
Wideband radio with very high potential data rates and with lower power consumption.
SUBMITTED BY -
NAME- SWETA SWAIN
ROLL NO - 00902062015
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