doc.: IEEE 802.11-01/xxxr0 Don Sloan, Cisco Systems November 13, 2001 6/3/2018 doc.: IEEE 802.11-01/xxxr0 .11g Higher Rate Modulation Compatible with .11a for Dual Band Radio Devices Don Sloan, Cisco Systems November 13, 2001 Don Sloan, Cisco Systems Don Sloan, Cisco Systems

This presentation supports This presentation supports .11g Higher Rate employing OFDM consistent with .11a for dual-band devices WHY? Dual-Band (2.4 & 5GHz) STA radios are a natural evolution in 802.11 systems. Much as dual-band and tri-band cellular phones allow seamless roaming across networks, dual- band 802.11 STA radios would support seamless roaming on all 802.11 networks (.11b and .11a). Public access with 2.4GHz in some areas, 5GHz in others. Don Sloan, Cisco Systems

Designing the .11g Higher Rate Standard with the same OFDM modulation as .11a makes dual-band STA devices practical. Uses the same Encoder/Decoder circuitry for both bands Same development and support knowledge for both bands With a common higher rate in .11g and .11a the two bands are effectively merged into one larger set of high rate channels. Don Sloan, Cisco Systems

Compatibility has some downside: .11b Header is long, impacting Higher Rate throughput. Eventually OFDM will likely proliferate replacing CCK in many systems allowing (optional) ultra-short headers with better throughput. We had a similar situation when 11Mbps short headers were introduced as optional in 1&2 Mbps 802.11 systems. Don Sloan, Cisco Systems

Both 802.11 bands viewed as one standard Conclusion: The 2.4GHz band migrates up in bit rate with a visible future consistent with the emerging 5GHz systems. Both 802.11 bands viewed as one standard .11g radios would use the same circuitry and technology as .11a in dual band radios OFDM received the most votes last time and is the apparent choice, let’s get behind it and move forward. Don Sloan, Cisco Systems