中文摘要：

在异构蜂窝网络中使用传统的小区选择方法会导致宏基站和小基站的负载失衡,而与小基站关联的用户面临服务质量（Qo S）的降低的问题。针对该问题,提出了一种基于效用函数最大化的用户与基站关联方法。该方法将用户与基站的关联过程建模为双目标优化问题并且线性化为系数可调的效用函数最大化问题,以实现基站负载均衡和用户Qo S之间的折中。通过设计权值系数,将该效用函数最大化问题转化为基于二部图的最大匹配,并用匈牙利算法求得最优解。仿真结果表明,该方法实现了异构蜂窝网络中宏基站与小基站之间的负载均衡,并且通过系数调节,达到了基站负载均衡和用户QoS之间的折中。

英文摘要：

In heterogeneous cellular networks, traditional user association schemes based on reference signal power result in load imbalances between macro cell base stations （MBSs） and small cell base stations （SBSs）. Meanwhile, offloading users to SBSs face the quality of service （QoS） degradation. In this paper, we propose a utility maximization framework to address the user association problem. In order to strike a tradeoff between load balancing and user QoS experiences, a bi-criterion optimization problem is formulated to solve the user association problem. The bi-criterion optimization problem is then linearized as a utility maximization problem with a tunable parameter. In addition, we show that the utility maximization problem can be reformulated as a maximum bi-partite matching problem and can be solved in polynomial time by using the Hungarian method. Simulation results show that our proposed method achieves load balancing and can strike tradeoffs between load balancing and user QoS by tuning the optimization parameter.