A projection based approach for radar and telecommunication systems coexistence

Abstract

We propose projecting radar waveform onto the null space of an interference channel matrix between the radar and a communication system as a solution for coexistence of radar and communication systems in the same band. This approach assumes that the cognitive radar has full knowledge of the interference channel and tries to modify its signal vectors in such a way that they fall in the null space of the channel matrix. We investigate the effects of null space projections on radar performance and target parameter identification both analytically and quantita tively by using maximum likelihood and Cramer-Rao bound performance bounds to estimate target direction in the two cases of no null space projection and null space projection. Through simulation we demonstrate that by optimal choice of the number of antennas, the performance and target identification capabilities of radar in our method are competitive with that of traditional radar waveforms, while simultaneously guaranteeing coexistence between radar and communication systems.

Cooperative radar and communications signaling: The estimation and information theory odd couple

“…where we used Equation (14). In this regime, the corresponding estimation rate bound R est is given by Equation (19).…”

MIMO Radar and Cellular Coexistence: A Power-Efficient Approach Enabled by Interference Exploitation

“…More relevant to ths work, transmit beamforming has been viewed as a promising solution to eliminating the mutual interference between radar and communication. First pioneered by [10], the idea of null space projection (NSP) beamforming has been widely discussed [10]- [12], where the radar waveforms are projected onto the null space of the interference channel matrix from radar transmitter to communication receiver. However, it is clear that perfect CSI is unavailable in realistic scenarios.…”

“…2) Following the typical assumptions in the radarcommunication literature [10], [11], [14], we assume that…”

Joint radar-communications performance bounds: Data versus estimation information rates

“…Some other techniques such as interference mitigation [11], precoding or spatial separation [12] or waveform shaping [13] allow both radar and communications to share the spectrum and coexist. In [13], waveform shaping is done by projecting radar waveforms onto the null space of the interference channel matrix, which ensures that there is minimal interference on the communications system from the radar system.…”

“…In [13], waveform shaping is done by projecting radar waveforms onto the null space of the interference channel matrix, which ensures that there is minimal interference on the communications system from the radar system.…”