On-Demand Receiver-Centric Channel Allocation via Constrained VCG Auction for Spatial Spectrum Reuse

Spatial spectrum reuse significantly enhances spectrum utilization but requires delicate design to avoid cochannel interference. Instead of focusing solely on spectrum efficiency, we consider maximizing social welfare via channel allocation. Specifically, we propose an on-demand receiver-centric mechanism with a new factor, the supply and demand relationship. The optimal channel allocation that maximizes social welfare can be achieved by the constrained Vickrey-Clarke-Groves (VCG) auction for secondary users (SUs), but with high complexity. To simplify the constrained VCG auction, we group the SUs into maximal independent groups (MIGs) using a modified Bron-Kerbosch algorithm. We prove that truthful bidding is the optimal strategy for the SUs even though they do not participate in the VCG auction for MIGs directly. Therefore, the MIGs are bidding truthfully and social welfare is maximized. We also prove that the optimal channel allocation is not unique and thus a weakly-dominant strategy for the primary user, and the VCG style pricing based on truthful bidding can be implemented by using a decision tree repeatedly. Furthermore, we approximate and simplify the optimal channel allocation with a greedy algorithm, Dijkstra's algorithm, and batch allocation. In our simulation, we compare the proposed methods and demonstrate that on-demand channel allocation increases social welfare.