Cooperative Spectrum Sharing between Radar and Communication Systems

Spectrum congestion in commercial wireless communications is a growing problem as high-data-rate applications become prevalent. On the other hand, frequency bands earmarked for exclusive use by radar are underutilized.  Spectrum sharing is a new line of work that aims to enable radar and communication systems to share the same frequency bands efficiently by managing interference.

In the first part of the talk we present our recent work on cooperative spectrum sharing for the coexistence of a MIMO radar and a MIMO wireless communication system. Radar transmit precoding and adaptive communication transmission are adopted, and are jointly designed to maximize some quality metric for the radar subject to the communication system meeting certain operational constraints. We focus on a special case of MIMO radar, namely the matrix completion based MIMO radar (MIMO-MC), which perform sub-Nyquist rate sampling of the received signal and then recover the missing samples via matrix completion. In addition to reducing the amount of data required, MIMO-MC radar offer a significant advantage for spectrum sharing. This is because the subsampling modulates the interference channel, making it easier for the communication system to design its transmission scheme.

In the second part of the talk, we present our work on another form of spectrum sharing, namely, on dual functional radar communication systems (DFRC). In DFRC systems communication information is conveyed by the radar probing signals, thus there is no interference between radar and communication functionalities. DFRC systems are of great interest in autonomous driving scenarios, where the same waveform can be used for sensing and for vehicle-to-vehicle communication. We present a novel DFRC system, consisting of a sparse MIMO radar whose active antennas transmit orthogonal frequency division multiplexing (OFDM) waveforms. The system communicates information via the transmitted data symbols and also via the activation pattern of the transmit antennas.