## 6 Conclusions  
In this paper, we presented the enabling methods and the experimentally-oriented feasibility study on the LHO utilizing a multi-RAT robotic platform in an indoor HetNets environment with the target to achieve enhanced link robustness as well as augmented throughput, thus enabling a self-organized communication system with autonomous vehicles. In terms of location awareness, we developed and presented the GBP algorithm for positioning the constructed robot. The corresponding positioning accuracy has been tested via simulations by utilizing the CRLB-level AoA measurements with the array orientation uncertainty taken into account. In addition to the numerical analysis, an experimental measurement campaign was conducted with the multi-RAT robotic platform in order to justify the feasibility of the proposed positioning algorithm as well as the LHO algorithm. Despite the coarse AoA measurements, our experimental results confirmed that the \"GBP+DR\" method is capable of providing sufficient positioning accuracy, which is essential to perform the LHO. With the obtained location awareness, the handover was carried out more precisely before the robot entered the NLoS region. Owing to a longer LoS connection with the mmWave AP, the LHO can achieve twice higher throughput than the conventional RSSI-based handover scheme. During the experiments, two independent data streams were maintained: one to control the telemetry connection and another one to provide video feedback between the robot and its remote operator. In both cases, session continuity targeted by the handover procedure was preserved, although a noticeable lag was observed in the video stream. Even though the performance of the LHO scheme is bounded by the practical limitations of the employed equipment, it was shown via simulations that the applied positioning approach is capable of offering accurate enough location estimates in realistic indoor environments, thus further improving the performance of the discussed LHO in a multi-radio environment. Four directions of future work are currently envisioned: (i) development of advanced algorithms for more accurate AoA estimation based on the received signals at the mmWave array on the robot; (ii) assessment of practical performance levels in different types of environments and under varying densities of multi-radio network deployments considering potential interference; (iii) study and investigation of a hybrid  
Figure 9: Practical implementation of location estimation algorithm, (a) WiGig beamforming variation; (b) Estimated and measured location. handover scheme integrating various metrics, such as RSSI and location awareness under different environments and scenarios; (iv) together with positioning, the sensing techniques will also be applied to produce a simulated environment for multi-RAT handover with efficient beamforming strategy, expanding the proposed algorithm well beyond the considered scenario. The main idea and objective of this research were identified by [PERSON], [PERSON], [PERSON] and [PERSON], and supervised by [PERSON], [PERSON] and [PERSON]; [PERSON] provided the state-of-the-art review, proposed and validated the positioning algorithm using simulation; [PERSON] implemented the two considered handover schemes experimentally; [PERSON] and [PERSON] wrote the major part of the original draft; [PERSON] modelled the office environment and provided the key coordinates for simulation study; A video was prepared by [PERSON] and [PERSON]; [PERSON], [PERSON] and [PERSON] reviewed the original manuscript and acquired the research funding. All authors have read and agreed to the published version of the manuscript. This research was financially supported by the Academy of Finland, projects PRISMA (313039) and ULTRA (328226 and 328214), the Finnish Foundation for Technology Promotion, the Finnish Funding Agency for Innovation under the project 5G VIIMA as well as the international mobility project MeMoV, No.