Beamforming Optimization: Extended to Bidirectional Integrated Sensing and Communication System

This paper investigates the joint transmit and receive beamforming of the bidirectional integrated sensing and communication (BD-ISAC) system. Through in-band full-duplex (FD), the BD-ISAC system aims to achieve the coexistence of bidirectional communication and radar detection. An optimization problem is proposed with the object of maximizing the weighted sum of communication rates, subject to the constraints of radar performance and interference suppression. To be more specific, the similarity between BD-ISAC beamforming weights and referential ones with ideal radar performance is constrained, therefore taking radar properties into account while optimizing communication rates. Nulling of interference is also introduced to tackle the challenges of self-interference within a node and mutual interference between nodes. An algorithm based on the weighted minimum mean square error (WMMSE) method is developed to tackle the non-convex problem. Numerical results demonstrate the effectiveness of the proposed beamforming method for BD-ISAC systems.