The performance of wireless signal generation and detection at millimeter-wave frequencies using baseband optical means is analyzed and experimentally demonstrated. Multigigabit wireless signal generation is achieved based on all-optical orthogonal frequency division multiplexing (OFDM) and photonic upconversion. The received wireless signal is optically modulated and detected using digital coherent detection. We present a theoretical model, ultimate performance limitations based on simulations as well as experimental validation of the proposed architecture. In order to demonstrate the RF scalability and bit-rate transparency of our proposed approach, we experimentally demonstrated generation and detection in the 60 GHz and 75-110 GHz band of an all-optical OFDM quadrature phase shift keying, with two and three subcarriers, for a total bit rate over 20 Gb/s.