ROTR: Role-Transformable Multi-Agent Resource Allocation for Nonstationary Vehicular Communications

Efficient wireless resource allocation is essential for supporting multi-vehicle cooperation. The service data exchanged among intelligent vehicles is typically diverse, with varying transmission requirements that shift according to applications and traffic conditions, leading to major fluctuation in communication situations. Existing multi-agent reinforcement learning based resource allocation methods are often inefficient in handling such nonstationary communication situations due to their rigid cooperation patterns. To this end, we propose a ROle-TRansformable multi-agent resource allocation method, named ROTR. This method adopts a hierarchical decision-making process, where a high-level agent at a base station (BS) dynamically plans and distributes cooperation roles (CRs) and cooperation behaviors (CBs) in response to fluctuating communication situations. The Low-level agents within the transmitting vehicles (TVs) perform role transformations based on the assigned CRs and subsequently receive behavioral guidance according to CBs, enabling dynamic adjustments in cooperation patterns to adapt to variable communication situations and make resource allocation decisions. Additionally, we introduce a non-BS-assisted mode based on policy distillation, which enables a seamless transition to independent operation without the BS, relying solely on local states to generate CRs and CBs, thereby facilitating global resource cooperation. Extensive simulation experiments demonstrate that the proposed framework optimizes resource efficiency in nonstationary vehicular communications.