Mobility management (MM) in Long‐Term Evolution (LTE) networks is a vital process to keep an individual User Equipment (UE) connected while moving within the network coverage area. MM Entity (MME) is the LTE component responsible for tracking and paging procedures and controlling the corresponding signaling between the UE and its serving cell, which is necessary for data‐packet exchange. Because of the massive increase in the density of mobile UEs, MME is burdened by the high volume signaling load, especially because most of that load comes from Tracking Area Update (TAU) and Paging messages, which are essential to exchange UE‐specific information with the network. To achieve cost‐efficient resource provisioning, many solutions have been proposed for TAU and Paging management to optimize not only UE experience (ie, battery power consumption) but also network resources (ie, bandwidth). In this paper, we discuss various solution schemes for TAU and Paging in terms of complexity, latency, and computation costs. Also, this review discusses the adverse effects of these solutions on the LTE Key Performance Indicators (KPIs). Furthermore, we present a new trend of MM solutions in LTE networks, called software‐defined network (SDN) and software‐defined virtualization (SDNV). To this end, we examine the existing schemes and challenges in the literature toward next‐generation wireless networks (eg, 5G, Internet‐of‐Things [IoT], and machine to machine [M2M] communications), and we describe user mobility models that are used to analyze the network performance.

中文翻译：

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LTE网络中的移动性管理实体回顾：功耗和信令开销

长期演进（LTE）网络中的移动性管理（MM）是至关重要的过程，可确保在网络覆盖范围内移动时各个用户设备（UE）保持连接。MM实体（MME）是LTE组件，负责跟踪和寻呼过程并控制UE及其服务小区之间的相应信令，这对于数据分组交换是必需的。由于移动UE密度的大量增加，MME受到大量信令负载的负担，特别是因为大部分负载来自跟踪区域更新（TAU）和寻呼消息，这对于与UE交换UE特定信息至关重要网络。为了实现具有成本效益的资源供应，已针对TAU和TAU提出了许多解决方案。寻呼管理不仅可以优化UE体验（即电池功耗），还可以优化网络资源（即带宽）。在本文中，我们讨论了TAU和分页的各种解决方案在复杂性，延迟和计算成本方面。此外，本文还讨论了这些解决方案对LTE关键绩效指标（KPI）的不利影响。此外，我们提出了LTE网络中MM解决方案的新趋势，称为软件定义网络（SDN）和软件定义虚拟化（SDNV）。为此，我们研究了文献中针对下一代无线网络（例如5G，物联网[IoT]和机器对机器[M2M]通信）的现有方案和挑战，并描述了用户移动性模型用于分析网络性能。