  Connected autonomous vehicles (CAV) constitute an important application of
future-oriented traffic management .A vehicular system dominated by fully
autonomous vehicles requires a robust and efficient vehicle-to-everything (V2X)
infrastructure that will provide sturdy connection of vehicles in both short
and long distances for a large number of devices, requiring high spectral
efficiency (SE). Power domain non-orthogonal multiple access (PD-NOMA)
technique has the potential to provide the required high SE levels. In this
paper, a vehicular PD-NOMA testbed is implemented using software defined radio
(SDR) nodes. The main concerns and their corresponding solutions arising from
the implementation are highlighted. The bit error rates(BER) of vehicles with
different channel conditions are measured for mobile and stationary cases. The
extent of the estimation errors on the success rate beyond the idealized
theoretical analysis view is investigated and the approaches to alleviate these
errors are discussed. Finally, our perspective on possible PD-NOMA based CAV
deployment scenarios is presented in terms of performance constraints and
expectancy along with the overlooked open issues.
