A multi-game approach for effective co-existence in unlicensed spectrum between LTE-U system and Wi-Fi access point

Cellular networks are facing the challenge of meeting aggressive data demand with limited licensed spectrum and LTE over the unlicensed band (LTE-U) has emerged as an effective way to defeat this hurdle. Using LTE-U along with superior techniques such as carrier aggregation (CA), one can boost the performance of existing cellular networks. Nevertheless, LTE-U can potentially deteriorate the performance of co-existing Wi-Fi systems operating over the unlicensed bands if not well-managed. Furthermore, single operator scenario is considered in most of the existing co-existence works. In this paper, an effective coexistence mechanism between LTE-U and Wi-Fi systems is investigated. The object is to facilitate the cellular networks to use LTE-U with CA to reduce the gap between achieved rate and quality-of-service (QoS) of the user while protecting Wi-Fi users, considering multiple operators in a dense deployment scenario. To resolve this problem, a multi-gaming approach is used. A cooperative Nash bargaining game (NBG) is used for sharing time resource in unlicensed for LTE-U and Wi-Fi systems. Following, a bankruptcy game is used by operators to allocate unlicensed resource among LTE-U users. Simulation results show that the proposed approach is better than the comparing methods regarding per user achieved rate, and fairness. It also shows that the proposed technique defends Wi-Fi user greatly in dense deployment than basic listen-before-talk (LBT) does.