## 5 Conclusions and Future Research  
We expect the remote control of machinery to assume a role in future smart farming. As technological advances in various fields are increasing the range of functions that machinery can perform autonomously, we are experiencing analogous developments in road traffic. The PRIORITY project has concentrated on researching and testing the capability for remote control using a local private mobile network as the communication medium. We have successfully demonstrated the viability of the remote operation of a tractor in a realistic environment. Future research is needed to support the transition toward more autonomy and thus improved efficiency and productivity. Appropriate regulatory and legislative changes must also be addressed within the boundaries of maintaining a high level of security and safety. The emergence of such changes will likely differ between different countries and regions. In fact, the application of new technologies may actually promote better safety by removing human error. The development of the trialed system enabled us to learn the need to customize applications and optimize protocols for private networks, where the available resources can be limited. In particular, we demonstrated the optimization of control channel signaling. In the future, emerging network and application technologies and architectures may provide new opportunities. More research is needed to find innovations to (a) adapt applications to restrictions caused by the network or (b) customize the network to support applications. For instance, tractor remote control traffic was implemented using the SSH protocol. The SSH tunnel is convenient, but because SCTP was used with Cannelloni, it introduced the need to perform a protocol conversion using the Socat program. In the future, there is room to replace SSH with end-to-end secure connections that offer better efficiency by eliminating the processing coming from conversion and more security by removing the need for the trusted conversion component. Furthermore, Cannelloni could use UDP instead of SCTP, allowing the dropping of some packets as congestion control. Dropping packets is preferable to inserting old messages into the CAN bus after retransmission is achieved. Approaches to adapting the quality parameters of low-latency video streams to support different 5G use cases were evaluated in our prior work [83, 84] within the project. Video adaptation solutions provide a promising approach for optimizing the video channels used by unmanned tractors. Future research is needed to develop and verify adaptation approaches for unmanned tractor scenarios. The security approach for coupling identity and access management and our new protocol [51] for attesting the trustworthiness of IoT devices were now demonstrated with farm sensors. Future research is needed to explore whether our combined identity management and delegated attestation architecture would be feasible for unmanned tractors. The trialed GEO satellites are able to provide large coverage and good throughput capabilities, but the main disadvantage of this solution is large latency, which limits the applicability of the GEO satellites mostly to monitoring use cases. Future work and trials are needed to explore the opportunities provided by low-earth orbiting (LEO) satellites. LEO satellites allow for dramatically decreased transmission latency due to their shorter distance from Earth (e.g., from 500-1400 km compared to 35,786 km for GEO). LEO satellite connectivity possibilities have been trialed, resulting in throughput of 195 Mbps and round-trip latency levels of 70 ms [85]. This connectivity performance would be sufficient not only for monitoring use cases but potentially also for the remote control of an unmanned tractor. Conceptualization, M.H., J.S., T.K., K.L., P.K., A.Y. and H.P. ; methodology, M.H., J.S., K.L., T.K. and H.P. ; software, O.S. and T.K. ; validation, O.S., T.K., K.L. and P.K. ; writing--original draft preparation, M.H., J.S., K.L., O.S., T.K., P.K., H.H., J.P. and A.Y.