Cognitive Radio and Dynamic Spectrum Access represent two complementary developments that will refashion the world of wireless communication. In order to investigate the roles of knowledge representation and reasoning technologies in this domain, we have developed an experimental cognitive radio simulation environment. That is, a conventional radio when operating in a particular communications mode always follows the same procedure and either succeeds or fails at a given task. A cognitive radio, by contrast, can use knowledge of radio technology and policy, representations of goals, and other contextual parameters to reason about a failed attempt to satisfy a goal and attempt alternate courses of action depending upon the circumstances.-Cognitive　Radio　and　Dynamic　Spectrum　Access represent　two　complementary　developments　that　will refashion　the　world　of　wireless　communication.　In order　to　investigate　the　roles　of　knowledge representation　and　reasoning　technologies　in　this domain, we have developed　an experimental　cognitive　radio　simulation　environment. That　is,　a　conventional　radio　when　operating　in　a particular　communications　mode　always　follows　the same procedure and either succeeds or fails at a given task.　　A　cognitive　radio,　by　contrast,　can　use knowledge　of　radio　technology　and　policy, representations　of　goals,　and　other　contextual parameters to reason about a failed attempt to satisfy a goal and attempt alternate courses of action depending upon the　circumstances.