Spectrum adaptive test terminal

Mobile User Objective System (MUOS) spectrum requirements call for the notching of the MUOS waveform to prevent interference with other users of the MUOS band. This function will be achieved via static host nation agreements (HNA) and dynamic scanning to discover narrowband users of the MUOS band. HNA and scanning data are used to develop a notch mask that is applied to the MUOS waveform before transmission. This paper describes the successful development of a spectrum adaptive test terminal for the MUOS program. This terminal dynamically adapts a wideband spread spectrum waveform in order to cooperatively coexist with existing radio systems. The paper addresses the characteristics of a spectrum adaptive terminal and the modifications of a COTS waveform to enable operation in a spectrum adaptive mode. The interface between the communication waveform and spectrum scanning function is explained. The scanning algorithm, including radiometric integration, noise floor contour determination, and signal detection, is described in detail. The notching algorithm, and associated scanning interface, is also described. An example of a spectrum adaptive terminal, the General Dynamics U.S. Navy Digital Modular Radio (DMR) AN/USC-61 (C) is presented. In addition, methods of reducing the effects of narrowband interference upon the wideband waveform are described.