Efficient Wideband Spectrum Sensing with Maximal Spectral Efficiency for LEO Mobile Satellite Systems

Area of Science:

• Wireless Communications
• Spectrum Management
• Cognitive Radio

Background:

• Static spectrum allocation policies lead to spectrum scarcity for satellite services.
• Narrowband spectrum sensing (SS) in cognitive radio (CR) is effective for terrestrial networks but not for wideband satellite signals.
• Secondary users (SUs) require efficient spectrum sensing to access licensed spectrum while protecting primary users (PUs).

Purpose of the Study:

• To investigate joint design of sensing time and hard fusion schemes for maximizing SU spectral efficiency in wideband spectrum sensing for Low Earth Orbit (LEO) mobile satellite services.
• To propose a novel wideband cooperative spectrum sensing (CSS) framework that extends sensing duration by utilizing reporting slots.
• To present a spatiotemporal CSS (ST-CSS) scheme for time-varying channels to achieve simultaneous space and time diversity gains.

Main Methods:

• A compressed detection model was established to identify the optimal sensing time for maximal spectral efficiency.
• A novel wideband cooperative spectrum sensing (CSS) framework was proposed, leveraging SU reporting durations for subsequent sensing.
• A spatiotemporal CSS (ST-CSS) scheme was developed for time-varying channels, employing a hard decision fusion rule.

Main Results:

• The compressed detection model confirmed the existence of an optimal sensing time for maximizing spectral efficiency.
• The proposed CSS framework effectively extends equivalent sensing time, enhancing sensing performance.
• Computer simulations demonstrated that the optimal sensing settings algorithm significantly improves spectral efficiency.
• The novel ST-CSS scheme achieved substantially higher spectral efficiency compared to general CSS frameworks.

Conclusions:

• Joint optimization of sensing time, hard fusion, and scheduling strategies is crucial for maximizing SU spectral efficiency in LEO satellite services.
• The proposed wideband CSS framework and ST-CSS scheme offer significant improvements in spectral efficiency and performance for satellite spectrum sensing.