 more Blue- quency-hopping scheme of the network accordingly. A tooth hop channels would cause symbol errors. However, serious obstacle to this method was lifted by a change to the adjacent channel Clac is on the order of 45 dB lower the FCC regulations governing spread-spectrum trans- than CIcc and would be noticed only when Bluetooth is missions in the 2.4 GHz band. Previously, frequency several centimeters away from the Wi-Fi terminal. hopping devices were committed to hopping over at least The effect of an environment where path loss is greater 75 pseudo-randomly selected hop channels. In August than in free space can be seen by using an exponent r = 3. 2002, paragraph 15.247, according to which Bluetooth For the same Wi-Fi range of 15 meters, the radius of and Wi-Fi devices are regulated, was changed to allow Bluetooth interference becomes 11.9 meters. a minimum of 15 nonoverlapping channels in the 2400 to While equation (5.2.1) does give a useful insight into 2483 MHz band. In addition, the regulation allows the range where Bluetooth devices are liable to de- employing intelligent hopping techniques, when less than teriorate Wi-Fi performance, its development did involve 75 hopping frequencies are used, to avoid interference simplifications. It considered that the signal-to-in- with other transmissions, and also suppression of trans- terference ratio that causes the error probability to mission on an occupied channel provided that there are a exceed a threshold is constant for all wanted signal levels, minimum of 15 hops. The Bluetooth specification which isn't necessarily SO. It also implies a step re- is due to be modified to take advantage of the adaptive lationship between signal-to-interference ratio and per- frequency hopping method of avoiding interference. formance degradation, whereas the effect of changing There are situations where adaptive frequency hop- interference level is continuous. The propagation law ping may not be effective or may have a negative effect. used in the development is also 