In heterogeneous cellular networks (HCNs), the energy reduction has a great impact on the operational cost and global carbon footprint, which has attracted more and more attention. To enhance the network energy efficiency (EE), we design two types of association mechanisms integrated with open loop power control (OLPC) for uplink code-division-multiple-access (CDMA) enabled HCNs. Specifically, they are formulated into two optimization problems that maximize the sum of users’ EEs and the one of users’ EE utilities. It is noteworthy that the one of these two mechanisms guarantees the user fairness by employing a logarithmic function. Considering that these formulated problems are in a fractional mixed-integer form and hard to tackle, we utilize a coalitional game to design two types of association algorithms with guaranteed convergence. To show the effectiveness of designed algorithms, another one is introduced for comparison in the simulation. As for them, we mainly investigate the impacts of user and BS densities on the association performance.

在异构蜂窝网络（HCN）中，节能对运营成本和全球碳足迹具有重大影响，已引起越来越多的关注。为了提高网络能效（EE），我们设计了两种类型的关联机制，它们与启用了上行链路码分多址（CDMA）的HCN的开环功率控制（OLPC）集成在一起。具体来说，将它们表述为两个最大化用户EE总数和一个用户EE实用程序总和的优化问题。值得注意的是，这两种机制之一通过采用对数函数来保证用户公平。考虑到这些公式化问题是分数混合整数形式且难以解决，我们利用联盟博弈设计了两种类型的具有保证收敛性的关联算法。为了展示设计算法的有效性，引入了另一种算法进行仿真比较。对于它们，我们主要研究用户和BS密度对关联性能的影响。