This work proposes a compression method developed to transport radio signals over a centralized radio access network using a functional split in which the fronthaul transports frequency-domain samples. The proposed method allows detecting which subcarriers from an LTE/NR OFDM symbol are inactive to avoid sending them over the fronthaul, hence decreasing the required throughput and making it vary with the radio usage. The proposed method was evaluated in different scenarios, and the results were analyzed in terms of user equipment goodput and fronthaul traffic. The simulations show a significant reduction in the fronthaul traffic, especially when the radio usage is low.