Wireless Technologies - 802.11b
We've come a long way since 2001, when the only choices available for wireless networking were the now-defunct Home RF and 802.11b. Flash forward to today and it seems like a new wireless technology or variation on an existing one appears every week. But when you peel away the proprietary boosting and stretching technologies that manufacturers have tacked on, you'll find that the actual number of standards-based technologies is smaller than you might think. Let's start with 802.11b.
The standard that started the "Wi-Fi" explosion, 802.11b operates in the 2.4GHz unlicensed frequency band (same as the one used by 2.4GHz cordless phones and microwave ovens), and uses DSSS (Direct Sequence Spread Spectrum) modulation. It has a maximum raw data rate of 11Mbps, with fallback rates of 5.5, 2, and 1Mbps.
802.11b was the first technology to be widely deployed and is still found in thousands of businesses and public Wi-Fi hotspots. For the most part, 11b has been eclipsed by the faster 802.11g, which leads the consumer, if not enterprise wireless networking market. However, 11b is still found in Wi-Fi phones, streaming music adapters, PDAs and other cost-sensitive applications where network speed requirements are lower.
Texas Instruments introduced an "enhanced" 802.11b in the first half of 2002 in the form of its ACX100 chipset, which used TI's PBCC (Packet Binary Convolutional Coding) modulation technique to boost the raw data rate from 11Mbps to 22Mbps. This advance was very popular and helped TI win some business from then market-leader Intersil. But the appearance of draft-802.11g products brought its rise in popularity to an abrupt halt. But not before versions claiming 44Mbps speeds also made a brief appearance.
- The most widely-available WLAN standard
- Relatively inexpensive
- Susceptible to interference from 2.4GHz cordless phones, microwave ovens and Bluetooth devices
- Susceptible to interference from neighboring wireless LANs due to only three available non-interfering channels available
Recommendation: 802.11g is a better choice and is backward compatible with 11b