For channel estimation in hybrid architecture: Here I will discuss communication between a BS (base station) and vehicles for mm Wave communication channel. Both N BS and N v have linear arrays (ULAs), with half-wavelength spaced antenna elements in a compact area uniformly. Let assume, f n is the beamforming vector at BS side. BS need to transmit a symbol, s , such that | s | 2 = 1. On the other hand, vehicle assigns a unit-norm measurement vector w m . Now, the signal received at MS (user) side is written by …………………………………………………..(vii) Where, H = N v X N BS matrix σ 2 = variance of white Gaussian noise …………………………………………………………….(viii) where α = channel gain a v (θ)= vehicle’s ULA array response for line of sight AOA (θ) a BS (φ)= For Line of sight AOD (φ), BS’s ULA steering vector response represented as ……………………………(ix) (Garcia, 2016) Equation (ix) showing phase difference in succeeding antenna elements of MIMO at vehicle and BS side, respectively. . …………………………………………...