Adaptive large MISO downlink with Predictor Antenna array for very fast moving vehicles

Recently, a “Separate Receive and Training Antenna” technique has been proposed to provide energy efficient and robust wireless downlink data transmission towards antennas placed upon fast moving vehicles. Energy efficiency is attained thanks to Large Multiple Input Single Output Beamforming. Robustness to beamforming mispointing at high speed is obtained by using the recent “Predictor Antenna” concept. However, for some speeds, the Separate Receive and Training Antenna technique suffers from residual mispointing. To improve the robustness of this technique, we propose three new schemes: the “Border Switch Off Scheme”, the “Random Switch Off Scheme” and the “Polynomial Interpolation” scheme. The two first schemes dynamically mute transmit antennas selectively when the residual mispointing is too severe. The third scheme generalizes the Predictor Antenna concept and uses all antennas upon the vehicle as a Predictor Antenna Array. These schemes are here assessed over spatially correlated channels. The two first schemes reduce energy saving to slightly improve robustness, whereas the third scheme perfectly compensates all speeds up to 300 kmph with maximum energy saving, at the cost of extra complexity.