Technical IEEE 802 11b Wireless LANs Wireless Freedom at Ethernet Speeds Paper IEEE 802 11b Wireless LANs Wireless Freedom at Ethernet Speeds Contents What s New in Wireless LANs The IEEE 802 11b Standard 2 The Competitive Advantage of Going Wireless 2 IEEE 802 11 and 802 11b Technology 3 802 11 Operating Modes 4 The 802 11 Physical Layer 4 802 11b Enhancements to the PHY Layer 6 The 802 11 Data Link Layer 6 Association Cellular Architectures and Roaming 7 Support for Time Bounded Data 9 Power Management 9 Security 9 Considerations for Choosing a Wireless LAN Ease of Setup 9 9 Ease of Management 10 Range and Throughput 10 Mobility 10 Power Management 11 Safety 11 Security 12 Cost 12 Conclusion 12 1 IEEE 802 11b Wireless LANs Wireless Freedom at Ethernet Speeds With the recent adoption of new standards for high rate wireless LANs mobile users can realize levels of performance throughput and availability comparable to those of traditional wired Ethernet As a result WLANs are on the verge of becoming a mainstream connectivity solution for a broad range of business customers The most critical issue slowing WLAN demand until now has been limited throughput This paper describes the new IEEE 802 11b standard for wireless transmission at rates up to 11 Mbps which promises to open new markets for WLANs It describes 802 11 and 802 11b technology and discusses the key considerations for selecting a reliable high performance wireless LAN Acronyms and Abbreviations AP access point BPSK Binary Phase Shift Keying BSS Basic Service Set CCK Complementary Code Keying CRC cyclic redundancy check CSMA CA Carrier Sense Multiple Access with Collision Avoidance What s New in Wireless LANs The IEEE 802 11b Standard CSMA CD Carrier Sense Multiple Access with Collision Detection A wireless LAN WLAN is a data transmission system designed to provide location independent network access between computing devices by using radio waves rather than a cable infrastructure In the corporate enterprise wireless LANs are usually implemented as the final link between the existing wired network and a group of client computers giving these users wireless access to the full resources and services of the corporate network across a building or campus setting WLANs are on the verge of becoming a mainstream connectivity solution for a broad range of business customers The wireless market is expanding rapidly as businesses discover the productivity benefits of going wire free According to Frost and Sullivan the wireless LAN industry exceeded 300 million in 1998 and will grow to 1 6 billion in 2005 To date wireless LANs have been primarily implemented in vertical applications such as manufacturing facilities warehouses and retail stores The majority of future wireless LAN growth is expected in healthcare facilities educational institutions and corporate enterprise office spaces In the corporation conference rooms public areas and branch offices are likely venues for WLANs CTS Clear to Send DCF Distribution Coordination Function DHCP Dynamic Host Configuration Protocol DS distribution system DSSS direct sequence spread spectrum ESS Extended Service Set ETSI European Telecommunications Standards Institute FCC Federal Communications Commission USA 2 The widespread acceptance of WLANs depends on industry standardization to ensure product compatibility and reliability among the various manufacturers The Institute of Electrical and Electronics Engineers IEEE ratified the original 802 11 specification in 1997 as the standard for wireless LANs That version of 802 11 provides for 1 Mbps and 2 Mbps data rates and a set of fundamental signaling methods and other services The most critical issue affecting WLAN demand has been limited throughput The data rates supported by the original 802 11 standard are too slow to support most general business requirements and have slowed adoption of WLANs Recognizing the critical need to support higher data transmission rates the IEEE recently ratified the 802 11b standard also known as 802 11 High Rate for transmissions of up to 11 Mbps Global regulatory bodies and vendor alliances have endorsed this new high rate standard which promises to open new markets for WLANs in large enterprise small office and home environments With 802 11b WLANs will be able to achieve wireless performance and throughput comparable to wired Ethernet Outside of the standards bodies wireless industry leaders have united to form the Wireless Ethernet Compatibility Alliance WECA WECA s mission is to certify cross vendor interoperability and compatibility of IEEE 802 11b wireless networking products and to promote that standard for the enterprise the small business and the home Members include WLAN semiconductor manufacturers WLAN providers computer system vendors and software makers such as 3Com Aironet Apple Breezecom Cabletron Compaq Dell Fujitsu IBM Intersil Lucent Technologies No Wires Needed Nokia Samsung Symbol Technologies Wayport and Zoom The Competitive Advantage of Going Wireless Today s business environment is characterized by an increasingly mobile workforce and flatter organizations Employees are equipped with notebook computers and spend more of their time working in teams that cross func tional organizational and geographic boundaries Much of these workers productivity occurs in meetings and away from their desks Users need access to the network far beyond their personal desktops WLANs fit well in this work environment giving mobile workers much needed freedom in their network access With a wireless network workers can access information from anywhere in the corporation a conference room the cafeteria or a remote branch office Wireless LANs provide a benefit for IT managers as well allowing them to design deploy and enhance networks without regard to the availability of wiring saving both effort and dollars Businesses of all sizes can benefit from deploying a WLAN system which provides a powerful combination of wired network throughput mobile access and configuration flexibility The economic benefits can add up to as much as 16 000 per user measured in worker productivity organizational efficiency revenue gain and cost savings over wired alternatives 1 Specifically WLAN advantages include Mobility that improves productivity with real time access to information regardless of worker location for faster and more efficient decision making Cost effective network setup for hard towire locations such as older buildings