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

Abstract

Abstract-We investigate cooperative radar and communications signaling. While each system typically considers the other system a source of interference, by considering the radar and communications operations to be a single joint system, the performance of both systems can, under certain conditions, be improved by the existence of the other. As an initial demonstration, we focus on the radar as relay scenario and present an approach denoted multiuser detection radar (MUDR). A novel joint estimation and information theoretic bound formulation is constructed for a receiver that observes communications and radar return in the same frequency allocation. The joint performance bound is presented in terms of the communication rate and the estimation rate of the system.

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

“…For the sake of simplicity we focus on range estimation only, as opposed to range and amplitude estimation. The joint system receiver will attempt to suppress the radar return using the predicted target range and then proceed to decode the communications signal as shown in [1]. While this may not seem pertinent now, this becomes convenient later, when computing the information rates (estimation and data) of both radar and communication systems [23].…”

“…We consider this information rate by considering the entropy of a random parameter being estimated and the entropy of the estimation uncertainty of that parameter [1]. As an observation, if the targets are well separated, then each target estimation can be considered an independent information channel.…”

“…We present the multiple-access communications system performance bound [25,23] as motivation to develop inner bounds on the performance of a joint radar-communications system [1]. In this scenario, the channel propagation gain for the first communications system is given by a 1 and channel propagation gain for the second communications system is given by a 2 .…”

“…In some scenarios, this implies that the timebandwidth product of the radar system will not be constant. In [1], a case was made for ensuring that the time-bandwidth product of the radar system would be fixed as constant which meant that the radar pulse duration would be constant. This would cause the duty-factor of the radar system δ to vary as well, which is not a desirable feature for radar systems.…”

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

“…In [2], a radar information rate has been defined, such that the performance of radar and communication can be discussed using the same metric. Similar work has been done in [3], [4], in which radar and communication are unified under the framework of information theory, and the channel capacity between radar and target has been defined by applying the rate distortion theory. Nevertheless, these works focus on the theoretical performance analysis rather than practical waveform design.…”