Radio Map-Based Spectrum Sharing for Joint Communication and Sensing Networks

Spectrum sharing among different wireless applications, e.g., communication and sensing (C&S), has become increasingly crucial in the upcoming sixth-generation (6G) era. To achieve effective coexistence, mutual interference should be mitigated. Motivated by this, we consider a joint communication and sensing (JCAS) network with distributed multiple-input and multiple-output (MIMO) configuration, and address the interference problem of spectrum sharing. A loose coordination regime is proposed which only requires C&S systems to exchange some position information. To do so, a site-specific database named the radio map is utilized to estimate the slowly-varying large-scale channel state information (CSI). On this basis, a joint power allocation scheme is designed to optimize the radar detection performance under a service constraint of the communication system. To tackle the complex nonlinear problem, the mathematical tools of the auxiliary function method and fraction programming are applied. An iterative algorithm is further proposed to solve this problem in a low-complexity way. Simulation results corroborate that the extrinsic information, i.e., position, is effective for geographically decoupling C&S interference. This will largely reduce the coordination complexity and cost in practice.