Achieving Unconstrained Signal Design for ISAC: Non-Coherent Processing and Beamforming Scheme

In this paper, we propose a signal design unconstrained ISAC framework, where different transmit signal design has no significant effect on both sensing and communication performance. To begin with, we describe the model of transmit signals with transmission power limitations. Next, the sensing and communication performance are analysed with reasonable metrics respectively. The property of unconstrained signal design is implied in a proved signal intensity distribution theorem, which facilitates the sensing function of our framework. Then, a beamforming optimization problem is formulated to maximize a weighted transmission rate subject to the guaranteed sensing performance. The formulated non-convex problem is approximately solved by alternatively solving two simpler sub-problems. Finally, numerical results are given to validate the effectiveness, practicality and satisfactory performance of our proposed framework.