User Localization Enabled Ultra-dense Network Testbed

We present an over-the-air testbed designed for assessing the performance of ultra-dense networks and related mobility management schemes based on tracking the location of user equipment. Location information of UEs at the physical layer of the radio access network allows for proactive and seamless handovers. This is particularly important for 5G ultra-dense networks where small cells may otherwise be overwhelmed by handover related signalling. We exploit sounding reference signals transmitted by UEs to track their location. Novel mobility management schemes can then be designed such that handover triggering is done by the network and without UE involvement. In current cellular networks, handover is triggered by downlink measurements carried out at the UE, and subsequent reporting. This work also validates our testbed's proof-of-concept software architecture based on stateless unordered worker threads. In particular, a Cloud-RAN of up to four radio transceiver points can be combined into a network overseen by one gNB. Also, dataplane support allows for experimentation with real-time data handovers. The obtained results demonstrate the feasibility of location-based handover schemes as a tool for future cellular network design.