Communication in a wireless network using a phase-tracking reference signal (PT-RS) for orthogonal frequency division multiplexing (OFDM) includes determining one or more PT-RS groups of adjacent subcarriers in a resource allocation for a physical uplink shared channel (PUSCH) or a physical downlink shared channel (PDSCH), encoding data to be transmitted by the PUSCH or the PDSCH in data subcarriers within the resource allocation for the PUSCH or the PDSCH, and encoding phase-tracking reference signals within the one or more PT-RS groups of adjacent subcarriers.