Broadcast Transmission Capacity of VANETs with Secrecy Outage Constraints under Multiple Frequency Bands

We study broadcast transmission capacity with secrecy outage constraints in a one-dimension vehicular ad hoc network model. We develop our model on the basis of a highway scenario and extend both ends of the highway to infinity, and vehicles are assumed to follow a homogeneous Poisson point process. We divide the fixed total bandwidth into a large number of sub-bands. In intuition, the increasing number of sub-bands theoretically can support more parallel communications simultaneously. However, the broadcast transmission capacity is not always increased with the increasing number of sun- bands. Hence, we study the relationship between broadcast transmission capacity and the number of sub-bands, and then deduce the optimum number of sub-bands. After that, we also derive the equation of the broadcast transmission capacity over Nakagami fading channels and the transmission capacity with the secrecy outage constraint, respectively. Finally, numerical results verify that there is an optimal number of sub-bands in different scenarios.