1 Coexistence in the 2 . 4 GHz ISM Band

The 2.4 GHz ISM band provides an attractive medium for developing tethered free applications based on current and proposed wireless standards. Since the ISM band is a shared spectrum allowing unlicensed operation of wireless services, coexistence between the wireless services needs to be considered to ensure performance requirements are maintained. A general method for evaluating coexistence is presented. The method is based on developing a stochastic model to evaluate coexistence in an arbitrary operational environment. To develop the model, a three-stage approach is used where the first two stages use empirical test results to estimate parameters and to substantiate the analytical model. By using the model, coexistence is evaluated based on variations in the operational environment, which takes into account the uncertainty in an installation’s location and in the interference traffic. This evaluation points to potential trouble spots and helps in determining strategies for alleviating them. In addition, the model can be used to evaluate techniques for mitigating coexistence and assist in optimizing their utility. The evaluation methodology is illustrated based on examining the IEEE 802.11b performance in the presence of Bluetooth piconets, however, the methodology is general and can be used to address other coexistence issues involving packet based wireless protocols.