mmWave Communications for High Mobility Devices: The Case of Road Side Links

Mobile communication at millimeter-waves (mmWaves) is affected by the rapid and random variations of the wireless environment. This requires accurate channel estimation at the receiver to compensate for the channel dynamics. The required channel training overhead has been shown to occupy a considerable fraction of the mmWave transmission bandwidth, especially when the mobile device (MD) moves at high-speed. We cope with the issue of the rapid variation of the channel by introducing a coherent transmission/detection technique, whose mechanism requires that MD has prior knowledge of its position as an alternative to the channel estimate. In particular, we consider the case of road side links with high-speed MDs and derive a closed-form expression for the optimal detector. We show that the proposed approach reduces the training overhead significantly at the expense of a signal-to-noise ratio (SNR) increase for a given bit error rate.