Mobility Robustness Optimization in Future Mobile Heterogeneous Networks: A Survey

Abstract

Ensuring reliable and stable communication during the movements of mobile users is one of the key issues in mobile networks. In the recent years, several studies have been conducted to address the issues related to Handover (HO) self-optimization in Heterogeneous Networks (HetNets) for Fourth Generation (4G) and Fifth Generation (5G) mobile networks. Various solutions have been developed to determine or estimating the optimum and ideal settings of Handover Control Parameters (HCPs), such as Time-To-Trigger (TTT) and Handover Margin (HOM). However, the complexity, high requirements, and the upcoming structure of ultra-dense HetNets require more advanced HO self-optimization techniques for future implementation. This paper studies HO self-optimization techniques that may implemented in the next-generation mobile HetNets by reviewing state-of-the-art algorithms. The solutions discussed in this survey are more focus on Mobility Robustness Optimization (MRO), which is a significant self-optimization function in 4G and 5G mobile networks. The applied solutions will preserve the continuous connection between the User Equipment (UE) and eNBs during UE mobility, thereby enhancing connection quality. The various algorithms and techniques applied to HO have revealed different outcomes. This paper discusses the pros and cons of these techniques, and further examines HO self-optimization challenges and solutions. New future directions for the implementation of HO self-optimization are also identified. This survey will contribute to the understanding of the issues related to mobility management, particularly in relation to the self-optimization of HO control parameters in future mobile HetNets.

Advanced Mobility Robustness Optimization Models in Future Mobile Networks Based on Machine Learning Solutions

“…Several research that applied different approaches to HO selfoptimization (i.e., MRO) are present. Our study [55] comprehensively addressed several non-ML methods applied to the MRO function for optimal HCP settings such as RSRP-based [56], [57], [58], [59], [60], [61], [62], [63], [64], [65], weight function [48], [66], [67], [68], fuzzy logic controller (FLC) [69], [70], [71], [72], [73], speed scenarios [74], [75], [76], [77], [78], [79], [80], UE speed with traffic load [70], dwelling time [81], and combined techniques (i.e., weighted FLC [82], Fuzzy AHP [83], and fuzzy TOPSIS [84]). have been applied in MRO.…”

“…But, drones' velocity-aware are required since high speed may lead to increasing in HO rates, HOPP, RLF. Therefore, several MRO studies based on UE's speed have been extensively addressed in our work [55].…”

“…The conflict in objectives between MRO issues (i.e., too late HO and too early HO) requires a proper setting value for the TTT and HOM. For instance, too late HO requires decreasing in TTT interval to avoid high RLF, while too early HO requires increasing in TTT interval to avoid high HOPP [8], [55]. This conflict between RLF and HOPP requires a proper configuration of the HCPs to reach to an optimal HO triggering.…”

Campus Quality of Services Analysis of Mobile Wireless Communications Network Signal among Providers in Malaysia

“…The keys of the 4G infrastructures are accessing information connected to a wide range of information and services, and receiving a large volume of information, data, pictures, voice, and video [15]. 4G is using the Orthogonal Frequency Division Multiplexing (OFDM) [16].…”

Convergence of Heterogeneous Wireless Networks for Future Communications: Architecture, Qos and Resource Management

“…This paper proposes a future network infrastructure, which includes various technologies such as NFV, SDR and SDN. In particular, we explore both existing standards and possible extensions for 4G/5G mobile networks, and consider several open questions for future research [4].…”