# A Survey of Handover Management in Mobile HetNets: Current Challenges and Future Directions
## 4 Handover Decision Techniques
### FLC-Based HO Decision Approaches
\begin{table}
\begin{tabular}{p{42.7 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline
**Ref. No Year** & **Criteria Parameter Selection** & **HCPs** & **KPI’s** & **Simulator** & **Achievement** & **Drawbacks** & **Fuzzy Rules** \\ \hline
2022 [84] & SINR, Cell Load, UE Velocity & HOM, TTT & HOPP, HOL & RLE, MATLAB & Eliminated LBO-MRO conflict by employing Cell Load instead of LBO and simulation results are relatively better than the [89] model in terms of HOPP, HOL and RLF & Complexity of the fuzzy model is greater than that of the original model \\ \hline
2019 [77] & SINR, Cell Load, UE Velocity & HOM, TTT & HOPP, HOF & RLE, MATLAB & WFSO scheme calculates the weights against input parameters, and results reduce HOF rate by 95.9\% & HCP adjustment according to UE requirements can further enhance the HO performance. & Weighted Fuzzy System 3 \(\times\) 3 \(\times\) 3 \\ \hline
2022 [94] & RSRP, SINR, Jitter, PLR & TTT & HOPP, HOP & MATLAB & Fuzzy-TOPSIS reduced the number of handovers by 90\% and HOP by 10\% as compared to RSRP method whereas, historical information based Clustering Fuzzy-TOPSIS further reduce the number of handover by 10\% and RIF by 3\% & Clustering Fuzzy-TOPSIS 5 \(\times\) 5 \(\times\) 5 \\ \hline
2020 [102] & Throughput, End-to-End Delay & Q-Parameter & HOD, Throughput, Latency & NS-3 & FL approach used E2 ED and throughput as input to HO depict an index, which gives 97\% better performance in terms of handover delay than compared technique. & They only considered throughput and EEED as handover input parameters, which may eliminate a lot of handover decision-making useful information & FLC \(\times\) 3 \(\times\) 3 \\ \hline
2018 [87] & RSRP, VESQU & HOM & HOPP, HOF, HomoP, Connectivity & MATLAB & Proposed scheme reduced the HOPP and shows prominent results for HOF and HOP & HCP, however, HOM along with TTT can produce better results & FLC \(\times\) 3 \(\times\) 3 \(\times\) 4 \\ \hline
2021 [88] & RSRP, VESQU & HOM, TTT & HOPP, HOP & MATLAB & The proposed approach reduces the reported for HOF probability by 0.5\% compared to 50\% and 10\% in [51, 87] & The performance evaluation can be extended for HCP, and user velocity support is also limited & FLC \(\times\) 3 \(\times\) 4 \(\times\) 4 \\ \hline
2021 [96] & SINR, SINR & Delta SINR & HOM & HOPP, RLF & MATLAB & The SINR distribution dynamically determines HOM according to the SINR and the change in SINR of a UE related this decay with the possible handover in near future & Use of SINR and change in SINR for RSRP, RSRQ, location and trajectory information is also considered for possible handovers & Use of SINR and change in SINR for RSRP, RSRQ, location and trajectory information is also considered for possible handovers & Use of SINR and change in SINR for RSRP, RSRQ, location and trajectory information is also considered for possible handovers & Use of SINR and change in SINR for RSRP, RSRQ, location and trajectory information is also considered for possible handovers & FLC (AHP) and TOPSIS 3 \(\times\) 4 \(\times\) 3 \(\times\) 3 \(\times\) 4 \\ \hline
2020 [90] & RSRP, RSRQ, SINR, UE Velocity & HOM & HOP, HOPP, HOP & MATLAB & The proposed scheme is the handover decisions by reducing HOF and HOPP & Higher link failures as compared to the other considered approaches & FLC (AHP) and TOPSIS 3 \(\times\) 4 \(\times\) 3 \(\times\) 3 \(\times\) 4 \\ \hline
2022 [90] & RSRP, RSRQ, SINR, UE Velocity & TTT & HOPP, HOP, HOP & MATLAB & Reduced the handover rate by 83\% and HOP by 76\%. & RIF and HOF are relatively on the higher sides as compared to the basic FLC models compared in this paper & Statistical Fuzzy System 3 \(\times\) 4 \(\times\) 4 \(\times\) 3 \\ \hline
2018 [79] & RSRP, RSRQ, UE Velocity & HOM & HOF, HOPP & MATLAB & The inclusion of the TTT can further enhance the effectiveness against handover decision process & FLC 3\(\times\) 3 \(\times\) 4 \\ \hline
2020 [109] & RSS, Throughput, PLR & NSF & Number of HOs, PLR, Throughput & MATLAB & This approach surpasses traditional and MADM-based fuzzy schemes in terms of the number of handovers and throughput performance & FLC 3\(\times\) 3 \(\times\) 3 \\ \hline \end{tabular}
\end{table}