A communication device generates: i) a physical layer (PHY) preamble of a PHY protocol data unit (PPDU), ii) a first portion of a PHY data payload of the PPDU, and iii) a second portion of the PHY data payload. The PHY preamble includes a first training field, and one or more second training fields. The first portion of the PHY data payload and the second portion of the PHY data payload include a plurality of first orthogonal frequency division multiplexing (OFDM) symbols. Each of multiple first OFDM symbols has a first duration. The communication device generates a PHY midamble of the PPDU to be included between the first and second portions of the PHY data payload. The PHY midamble includes one or more third training fields, each including a respective second OFDM symbol having a second duration shorter than the first duration.