Scaled‐time OFDM experiments for channels exceeding the cyclic prefix

Wireless communications experiments at high user velocities can be performed with much less effort at lower velocities by using time‐stretching techniques. In OFDM, state‐of‐the‐art time‐stretching techniques do not consider the case of channel impulse responses exceeding the length of the cyclic prefix (CP). This is the case in any real‐world OFDM system. In particular, multipath scenarios caused by relay nodes commonly found in public railways have a late, strong channel tap. In this work, the authors propose a time‐stretching technique that preserves the effects of the insufficient CP with negligible error and without channel knowledge.