Game theoretical analysis of coexistence in MIMO-empowered Cognitive Radio Networks

In Cognitive Radio Networks (CRNs), the spectrum underlay approach enables primary and secondary networks to transmit simultaneously, as long as the interference from the secondary network to the primary network is below certain threshold. As the recent advancement of the underlay approach, the transparent coexistence exploiting MIMO interference cancellation was proposed. Previous works assume that the secondary networks will completely follow the spectrum access rules by restricting their interference towards the primary network. However, this assumption might be invalid in practice due to the selfish nature of CRN users. In this work, we study the multi-hop MIMO-empowered secondary network's incentives of following or violating this rule through compliantly canceling or non-compliantly ignoring its interferences towards the primary network. Specifically, we model the coexistence between the primary and secondary networks as a Stackelberg game. The equilibriums reveal the secondary network's non-compliant incentives. These insights help in developing the methodology to deal with such type of selfish secondary networks.