Energy-Efficient Integrated Sensing and Communication in Collaborative Millimeter Wave Networks

Integrated sensing and communication (ISAC), which integrates sensing capabilities into wireless communication networks, is emerging as a key technology for future millimeter wave (mmWave) communication networks. Given the limited ISAC capability and energy budget of a single base station (BS), this paper studies how to enable energy-efficient sensing and communication via multi-BS collaborative sensing, where each sensing task is served by its most energy-efficient BS as much as possible, with the help of other BSs. Since unregulated multi-BS collaboration may lead to energy wastage and further aggravates the energy consumption in mmWave networks, an energy-efficient collaborative ISAC scheme is proposed, where multi-BS collaborative sensing and dual-functional radar and communication (DFRC) beams are judiciously utilized to reduce the network's energy consumption. We formulate the design of the energy-efficient collaborative ISAC scheme as a mixed integer nonlinear programming problem by jointly considering task allocation, beam scheduling, and transmit power control. Then, an energy-efficient cooperative beam scheduling (EE-CBS) algorithm is developed for efficient solution finding. Through extensive simulations, the proposed scheme is shown to significantly reduce the network's energy consumption when compared to the scheme without multi-BS cooperation or the utilization of DFRC waveforms.