On Design of Monostatic MIMO OFDM Integrated Communication and Sensing System

We propose a novel monostatic multiple-input multiple-output (MIMO) integrated sensing and communication (ISAC) system to provide high resolution 4D information of sensing targets with a low proportional communication capacity loss. This system colocates the ISAC transmitter and radar receiver, using unified orthogonal frequency division multiplexing (OFDM) signals for both communication and sensing tasks. We introduce a frequency resource allocation strategy that sets aside sparsely distributed blocks of subcarriers for ISAC and reserves the remaining subcarriers for conventional communication tasks. The cyclic-shift-based port virtualization technique is utilized on ISAC subcarrier blocks to synthesize a large 2D virtual array, enhancing angle resolution for sensing, and broadcast data with spatial diversity. Additionally, to ensure both sensing accuracy and high communication data rates, we present an ISAC subcarrier block selection method that optimizes the sparse placement of blocks through specific design constraints. Numerical examples demonstrate that our proposed monostatic MIMO ISAC system effectively balances communication and sensing performance, showing significant potential for future sixth-generation (6G) applications.