  The 5G and beyond wireless systems, instead of being just an extension of 4G,
are regarded as `network of networks' which is expected to integrate
heterogeneous wireless networks including wireless vehicular networks (WVN).
The WVN promises to solve many issues such as reducing road accidents, traffic
jams, fuel consumption and commute time, which is subject to various security
issues such as eavesdropping, where attackers attempt to overhear the secret
transmitted signal passively (which makes the detection/defense very
difficult). In this work, our objective is to implement a security scheme by
improving the secrecy capacity in Sub-6 GHz and millimeter-wave (mmWave) bands.
Vehicle-to-Infrastructure (V2I) for 5G and beyond wireless network. Unlike
previous works where the secrecy capacity is increased by randomly augmenting
the source power or setting the system combiners/precoders, in this work we
employ the Gradient Ascent algorithm to search for the best combiners/precoders
that maximize the secrecy rate performance. We further present two different
optimization scenarios: fixed and variable transmission power.
