I. Introduction
In heterogeneous wireless network (HWN), intensive infrastructure deployment has been proposed to further enhance network capacity by increasing spectral efficiency [1]. From the perspective of users’ experience, it is not a reasonable option to blindly pursue throughput maximization [2]. Due to significant differences in application types and user preferences, more users may feel variable Quality-of-Experience (QoE), even when owning the same throughput [3]. As a critical factor of driving HWN optimization, QoE optimization is primarily conducted in this letter.