Potential Frequency Interference Between 802.11 and Bluetooth

A current problem is that both Bluetooth and 802.11 products operate in the same 2.4GHz unlicensed radio band. This poses a strong potential for radio frequency interference between products based on both technologies. The likelihood is that Bluetooth products will jam the operation of 802.11, not the other way around. The reason is that Bluetooth hops through frequencies 600 times faster than 802.11. While an 802.11 device is transmitting on a particular frequency, a nearby Bluetooth product will most likely interfere with the 802.11 transmission many times before the 802.11 device hops to the next frequency. This barrage of radio signals emanating from Bluetooth products could seriously degrade the operation of an 802.11 network. Because the FCC doesn't directly mediate frequency conflicts between products within unlicensed ISM bands, Bluetooth and IEEE standards groups are left on their own to haggle over resolving the interference problems. The IEEE has taken a positive step forward by forming the 802.15 Coexistence Task Group 2. This group is developing recommended practices for coexistence of wireless personal access networks (PANs) that operate in the 2.4GHz frequency spectrum, and they've done preliminary analysis of the interference potential between 802.11 and Bluetooth. In addition, the group has made preliminary recommendations on how to solve the problem. The ultimate goal is to decrease the probability of Bluetooth and 802.11 devices transmitting at the same time. Refer to IEEE 802.15's Web site at http://grouper.ieee.org/ groups/802/15/pub/TG2.html for more information on progress this group is making.

TIP If no frequency management organization exists within your company, run some tests to determine the propagation patterns within your building. These tests let you know whether existing systems might interfere with, and thus block and cause delay to, your network. You will also discover whether your signal will disturb other systems.