by the DeviceManager on boot-up, the DMD is the first to both a PRF, which contains a list of properties for that file that is read by the DomainManager on boot-up, and component, and the SCD, which contains a list of the the SAD is the first file that is read by the Applica- interfaces supported by that component. In the case of tionFactory when asked to create an application. Each of the DCD, an additional track exists to describe the actual these files will contain not only information about that hardware, the DPD. The DPD, much like the SPD, specific component, but one or more (in the case of the contains information about that specific component, in DMD, only one) references to an SPD. One SPD in this this case, the hardware side. The DPD, also mirroring the list of references contains information about that spe- SPD, contains a reference to a PRF, which contains cific component. Any other SPD reference is for an properties information concerning capacities for that additional component in that system: in the case of the particular piece of hardware. Domain Profile <<DTDElement>> DomainManager <<DTDElement>> Device Configuaration Descriptor Configuration Descriptor Software Assembly Descriptor <<DTDElement>> Profile Descriptor <<DTDElement>> <<DTDElement>> Software Package Descriptor Profile Descriptor 0...1 <<DDDElement>> 0...n <<DDDElement>> <<DDDElement>> Device Package Descriptor Properties Descriptor Software Component Descriptor Figure 2.4a-12 Files describing different aspects of an SCA radio. The software defined radio as a platform for cognitive radio CHAPTER 2.4a Network Waveform Application External Physical Network Connection A Data and Real-Time Control B Non-Real-Time Control, Setup and Initialization, from Applications, Other Levels, User Interface Figure 2.4a-13 SCA API for interlayer communications (I/O = input/output; MAC = medium access control; LLC = logical link control). Application programming interface 2.4a.5 Applications To increase the compatibility between components, it is importa