The mobile network operation in the unlicensed spectrum offers opportunities for non-public connectivity services without the financial burden of spectrum licensing. Previous studies regarding unlicensed spectrum operation have mainly relied on analysis or simulation without addressing practical constraints. In this work, we designed, implemented, and evaluated the listen-before-talk protocol as a co-existence medium access mechanism on top of the 5G-NR physical layer. We propose different TDD configurations to enable different sensing frequencies. We enabled OpenAirInterface operation in the n46/n47 bands, a European band dedicated to connected intelligent transportation services. We evaluate the performance of unlicensed 5G-NR under bursty cross-traffic from a different device. The results show that the frequency of cross-traffic bursts affects BLER (Block Error Rate) and throughput more than their duration. The design of the TDD frame to offer more frequent sensing opportunities allows for reduced BLER but negatively impacts achievable throughput in the current setup.