The explosion of mobile communication devices and diversification of emerging media content put forward higher requirements for mobile communication networks in various aspects such as overall throughput, fairness and user experience. Fortunately, non-orthogonal multiplexing (NOM) techniques such as layered-division-multiplexing (LDM) and the flexible compatibility of physical layer design in fifth generation mobile networks (5G) open up the possibility to tackle the challenges. In this paper, we propose to use LDM-based layered multicast to improve network performance, where the multicast content is delivered with differentiated quality in different LDM signal layers. For various performance optimization purposes such as maximum throughput, proportional fairness, minimum dissatisfaction index, and maximum service satisfaction index, a unified analysis framework is developed. Under this framework, we formulate a joint optimization problem of layer-user pairing and power allocation. In order to solve this problem, an optimization algorithm based on subproblem decomposition is proposed, which arranges each multicast subscriber of the multicast content to receive the most suitable LDM layer, and finds the optimal transmit power and data rate for each layer. Simulation results demonstrate the superiority of LDM-based layered multicast over existing multicast approaches while guaranteeing the coverage and the lower limit of user experience.

中文翻译：

---

基于LDM的分层组播性能分析与优化


移动通信设备的爆炸式增长和新兴媒体内容的多样化，在整体吞吐量、公平性和用户体验等各方面对移动通信网络提出了更高的要求。幸运的是，分层复用 (LDM) 等非正交复用 (NOM) 技术以及第五代移动网络 (5G) 中物理层设计的灵活兼容性为应对这些挑战提供了可能性。在本文中，我们建议使用基于LDM的分层组播来提高网络性能，其中组播内容在不同的LDM信号层中以不同的质量传送。针对最大吞吐量、比例公平、最小不满意指数、最大服务满意度指数等各种性能优化目的，开发了统一的分析框架。在此框架下，我们提出了层用户配对和功率分配的联合优化问题。为了解决这一问题，提出了一种基于子问题分解的优化算法，将多播内容的每个多播订阅者安排到最合适的LDM层接收，并找到每层的最佳发射功率和数据速率。仿真结果表明，基于LDM的分层组播在保证覆盖范围和用户体验下限的同时，相对于现有的组播方法具有优越性。