Performance enhancement via RAT association control in multi-RAT cellular networks

From the perspective of a single user, occupying all available radio access technologies (RAT) is always beneficial for increasing data rate. However, due to the interactions among the users, occupying multiple RATs at each user might not be optimal in a network view point. This paper studies the optimal association strategy to maximize the system throughput in multi-RAT cellular networks. To this end, with stochastic geometry, we derive the network sum rates by considering two association modes; single RAT association (altruistic association) and multiple RATs association (selfish association). By comparing the network sum rates for the two association modes, we show that optimally balancing the number of users between two association modes is necessary to improve the performances. With some numerical examples, we investigate how various system parameters, such as the number of carrier components, user density, and density of access points, etc, affect on the optimal portion of the users between two association modes.