It depends on a lot of things; OFDM modulation multi path and fading mitigation, MIMO space-time coding for channel capacity increases, adaptive beam forming, e

It depends on a lot of things; OFDM modulation multi path and fading mitigation, MIMO space-time coding for channel capacity increases, adaptive beam forming, error correction, efficient power amplification, base-band processing. For Google's line of sight application, the adaptive beam forming and power amplification are the main tech drivers.