RAST: Radar as a subscriber technology for wireless spectrum cohabitation

Abstract

A new method is described that allows for the non-interfering spectrum coexistence of radar and a wireless communication system employing multiuser subscriber waveforms. To simultaneously achieve compatibility and requisite radar performance, the radar “subscribes” to the network and utilizes K independent subscriptions. In the case of a cellular network, this would correspond to K independent cell subscriptions operating simultaneously. To achieve requisite radar performance, the onboard radar controller performs an adaptive linear combiner optimization of the K simultaneous waveforms to obtain a transmitted composite waveform with far superior useful radar properties (greater power, Doppler tolerance, etc.) than would be achieved by simply using the indigenous unaltered communications network waveforms. The linearity of the superposition ensures that the composite radar waveform behaves as K ordinary users, and thus does not require any special handling by the communications network nor will result in any undue interference. While utilizing communication waveforms for radar is not new, using a plurality of simultaneous waveforms to form a new composite waveform with better radar properties yet preserving network compatibility is entirely new.