Spectrum Adaptability Scan based Notching in MUOS

Abstract

The DoD's next generation UHF SATCOM system, the Mobile User Objective System (MUOS), utilizes a 3G cellular WCDMA waveform in which satellites function as the cell towers. The system's large 5MHz channel bandwidth makes it necessary to be able to "lock out" frequencies with existing legitimate RF network traffic to avoid causing interference to these other users, a process called "notching." To evaluate the method of terminalbased scanning followed by notching for detected user nets, we first reduce RF spectrum analyzer collection campaign data then develop a model to test the effectiveness and efficiency of a WCDMA scan-thennotch spectral etiquette algorithm. Real-world analyzer data is first filtered for half duplex network activity and its hold and interarrival time statistics. The statistics help define the persistence, or dwell, of dynamic WCDMA spectral notches at net frequencies. Using simulated trial runs against the reduced analyzer data, the algorithm is evaluated for its effectiveness in protecting the nets and in preserving the WCDMA link. The relative costs and benefits of the scan-then-notch algorithm are considered in a summary analysis.