Wireless LANs

Comparison of Wireless LAN Standards - 802.11a versus 802.11b 

MobileInfo Advisory Notes and Comments

• Different radio frequency and modulation types of 802.11a and 802.11b causes interoperability problems - though access points with dual radios and roaming have started appearing. Without these type of access points, a device with 802.11b card will not be able to use 802.11a access point.
• Because of distance limitation issue with IEEE 802.11a standard, you may need as many as 16 times the number of access points as with 802.11b  - wiring the access points could be complex. For large areas like warehouse or a factory, IEEE 802.11b deployment would be more cost effective than one based on IEEE 802.11a unless there is need for bandwidth-hungry applications.
• IEEE 802.11a standard is suitable for large number of users in fairly close proximity accessing applications that require high bandwidth - video streaming, transmission of large files. Also because of signal penetration characteristics in the two bands, IEEE 802.11a standard based equipment would be more suitable in relatively open offices rather than in enclosed offices with thick walls.
• You can increase distance coverage by a higher power of access points and antennas. This is an area where you must do more thorough investigation and ultimately do tests in your specific environment.
• Synad, a UK company has developed 802.11a/b chip set that will allow the device to sense which access point is present.