# Handover Decisions for Ultra-Dense Networks in Smart Cities: A Survey
## 3 Related Works
### Summary of Works in Handover Methods
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Authors** & **Methods** & **Key Parameters** & **Key Findings** & **Limitations** \\ \hline [PERSON] et al. (2022) [31] & Fuzzy Logic (FLDHDT) & SINR, speed, HOM, TTT & Improved adaptability in UDNs & No load balancing, simulation only \\ \hline [PERSON] et al. (2020) [53] & FL + ANN & SINR, RSS, velocity & High accuracy, lower complexity & No real-world constraints \\ \hline [PERSON] et al. (2021) [54] & Q-Learning + Fuzzy CNN & Signal, distance, density, LoS & 25\% fewer unnecessary handovers & No security considerations \\ \hline [PERSON] et al. (2017) [55] & FL + ANN & RSS, distance, channel availability & Reduced ping-pong effects & No real-time mobility models \\ \hline [PERSON] et al. (2017) [42] & AHP-CG & Traffic type, network load, link quality & Optimized network selection, reduced packet loss & No mobility prediction \\ \hline [PERSON] \& [PERSON] (2021) [43] & FAHP-TOPSIS & QoS, handover cost, energy efficiency & Reduced redundant handovers & No security considerations \\ \hline [PERSON] \& [PERSON] (2017) [44] & Multicriteria decision & Cost function, speed, RSS, network occupancy & Improved traffic distribution & No real-world mobility fluctuations \\ \hline [PERSON] et al. (2021) [45] & Markov Decision Process (MDP) & Channel load, link quality, mobility patterns & Reduced handover occurrences & No multi-cell coordination \\ \hline [PERSON] et al. (2015) [46] & Multicriteria VHD & RSS, speed, traffic class, network occupancy & Improved network balance & No real-time constraints \\ \hline [PERSON] et al. (2015) [47] & SDN-based VHD & RSS, bandwidth, delay, jitter, speed, app type & 60\% fewer handovers & No interoperability considerations \\ \hline [PERSON] \& [PERSON] (2022) [48] & Stochastic geometry & handover rate, velocity, BS density, group-cell size, cooperation signaling overhead, coverage probability, dual-slope path-loss exponents & The proposed CCHO scheme reduces handover rates by up to 72.7\% compared to conventional and static cooperative methods & The study does not analyze the computational overhead or real-time latency of SDN-based group-cell management \\ \hline [PERSON] et al. (2025) [3] & Unscented Kalman Filter & RSRP, SINR, speed, handover success rate, latency, throughput, packet loss ratio, offset adjustment & The proposed UKF + E-SARSA & The model assumes ideal network feedback and handover model improves handover success rate by up to 15\% compared to traditional algorithms & The model assumes ideal network feedback and worker to reduce network feedback and worker to verify the model’s real-time applicability \\ \hline [PERSON] et al. (2023) [49] & Analytical modeling using Poisson cluster process & Density, scattering variance, speed, handover thresholds & The proposed UKF + E-SARSA handover model improves accuracy, which may not be feasible in practice; no hardware or testbed validation was conducted to verify the model’s real-time applicability \\ \hline [PERSON] et al. (2023) [49] & Analytical modeling using Poisson cluster process & Density, scattering variance, speed, handover thresholds & The proposed UKF + E-SARSA handover model improves accuracy, which may not be feasible in practice; no hardware or testbed validation was conducted to verify the model’s real-time applicability \\ \hline [PERSON] et al. (2023) [56] & AI-based techniques, fuzzy logic, and multi-attribute decision-making & Handover control parameters, optimal base station selection & Proposed model ensured seamless mobility in both terrestrial and non-terrestrial scenarios \\ \hline [PERSON] et al. (2021) [50] & RL-based techniques & Handover failure rate, ping-pong rate, and latency & The survey highlights the growing complexity of HO management & Little real-world deployment \\ \hline [PERSON], [PERSON] (2022) [39] & RL-based techniques & - & The survey focused on the limitations of conventional handover mechanisms & No practical deployment case studies \\ \hline [PERSON] et al. (2024) [9] & Random Forest, MLP, and GRU & RSRP and SINR & Proposed model predicted future serving cells with high accuracy & Lack of real-world testing \\ \hline \hline \end{tabular}
\end{table}