Wi-Fi technology evolved from early wireless LAN experiments in the 1970s that were later abandoned due to performance and regulatory issues. The emergence of unlicensed frequency bands in 1985 and IEEE 802.11 standards starting in 1990 drove the development and adoption of Wi-Fi for business, home, and mobile networks. 802.11 standards including a, b, g, and n improved speeds and compatibility while operating in the 2.4GHz or 5GHz bands, with later standards adding improvements like better coverage, increased speeds and capacity. While enterprises were initially the main users, residential adoption of Wi-Fi surpassed businesses due to lower costs and simpler installation, finding applications in healthcare, education, retail and warehousing

1. Wi-Fi

2. Evolution of Wireless LAN Early experiences (1970-72): IBM, HP, Motorola Abandoned due to limited performance and unavailability of frequency bands Early challenges: Complexity and cost Bandwidth Coverage Interference Frequency administration Emergence of unlicensed bands Release of Industrial, Scientific and Medical (ISM) bands in 1985 Applications: military, home and enterprise networks, mobile networks, teetherless access

3. Wi-Fi is based on 802.11 technology It is originally intended to provide wireless computing for staffs within businesses and commercial organizations

4. IEEE 802.11 Standardization group formed in 1990, first standards completed in 1997 IEEE 802.11 is the first WLAN standard; only one to secure a market 802.11a: PHY layer supports 11Mbps using CKK (complementary code keying) technology 802.11b: PHY layer supports 54 Mbps using OFDM Uses CSMA/CA for contention data Supports both infrastructure as well as ad hoc modes

5. 802.11a – higher speeds, smaller coverage, more channels Wi-Fi is also sold to hotspot operators particularly hotel, convention centres, cafes, airports Hotspots offer higher-speed Internet access than most cellular network’s data offering and cost less to build than cellular base station 802.11 wireless standards are based on Ethernet protocols 802.11a is the only 802.11 standard that operates at 5 GHz The use of 5 GHz band avoids interference from microwave ovens, Bluetooth equipments and cordless phones that operate at 2.4 GHz Disadvantage is the signal fade faster

6. 802.11b When they were first available, 802.11 equipments were equipped with only 802.11b chips Now most use b and g which are designed to interoperate Because home broadband connections are slower than 802.11 networks, no advantage is gained

7. 802.11g Support higher data rates than 802.11b Use 2.4 gHz bands The higher speeds and capacity of g and a are required to support voice over IP on WLANs

8. 802.11n Backward compatibility with a, b and g Improve coverage by overcoming a certain amount of interference Increase speeds and supports more users per access point

9. Benefits.. Residential customers adopted Wi-Fi faster than enterprises because of its simplicity, fewer concerns about security and the benefit of avoiding the expenses for cabling Its advantage is low equipment cost and easier installation Benefits were also immediately noticed for healthcare, education, retailing and warehousing

10. Disadvantages.. Because of the casual nature of Wi-Fi users, most of them don’t protect their Wi-Fi networks with strong passwords – This weakness can be exploited by unauthorized persons which (advertently) can gain access to the Wi-Fi and can exploit it to satisfy their personal or professional needs.