Cooperative and collaborative resource management in small cell networks using game theory

The ubiquitous coverage/connectivity requirement of wireless cellular networks has shifted mobile network operators’ interest toward dense deployment of small cells with coverage areas that are much smaller as compared to macrocell base stations. However, the advantages of small cells could come short whenever neighboring small cells compete to utilize common spectral resources that would result in severe interference. In such considerations, we propose a cooperative and collaborative resource management (CCRM) framework that enables cooperative intra-connection among small cells of an operator and collaborative interconnection among multiple operators for proper utilization of network resources (both infrastructures and spectrum). To look for distributed resource (subchannel) allocation, first, we study the performance of best-response (BR) strategy as a game theoretic solution analyzed under the physical interference model. The traditional BR dynamics require centralized scheduler(s) to choose a player to perform sequential update of their strategies. In this regards, we study for these two cases: (i) to overcome requirements of centralized coordination for sequential updates when players acts as non-cooperative decision-makers, and (ii) to speed-up convergence provided that players are cooperative decision-makers. Our proposed schemes overcome limitations associated with the traditional BR dynamics: stochastic BR avoids requirement of centralized coordination for sequential updates in non-cooperative SCNs, and coordinated actions speed-up convergence to a steady-state in cooperative small cell networks. Although the problem of distributed resource allocation can be addressed through the proposed schemes following BR dynamics, the existence of a steady-state solution, i.e., a pure strategy Nash equilibrium, cannot be guaranteed. To guarantee for the existence of a steady-state solution, we utilize the concept of marginal contribution and propose marginal contribution-based best-response (MCBR) algorithm to cope with dynamic and limited in- formation in the small cell network. Here, the objective is to find a distributed subchannel allocation that maximizes the welfare of the small cell network, defined as the total system capacity. MCBR is theoretically proven to be an exact potential game, which is a class of potential game that guarantees convergence to a pure strategy steady-state, i.e., the Nash equilibrium. Finally, we introduce multi-operator collaboration that would provide virtualization of network resources (infrastructure and spectrum) and enable its efficient utilization, i.e., uninterrupted coverage and connectivity to subscribers, and an opportunity to avoid under-utilization of the network resources. However, a mobile network operator (MNO) with exclusive ownership to network resources would have little incentive to utilize its precious resources to serve users of other MNOs, since MNOs differentiate among others based on their ownership of the licensed spectrum. Thus, considering network resources scarcity and under-utilization, we propose a mechanism for multi-operator small cells collaboration through negotiation that establishes a mutual agreement acceptable to all involved parties, i.e., a win-win situation for the collaborating MNOs. It enables subscribers of a MNO to utilize other MNOs’ network resources, and allows MNOs to offer small cells "as a service" to users with ubiquitous access to wireless coverage/connectivity, maximize the use of an existing network resources by serving additional users from a market share, and enhance per-user data rate.