A method for wireless communication, the method comprising: generating, at a communication device (114, 154-1, 154-2, 154-3), a physical layer, PHY, preamble (204; 300; 350) of a PHY protocol data unit, wherein the PHY preamble is generated to include i) a first training field to be used by a receiver (122, 162) for synchronization, and ii) one or more second training fields (336-1, 336-M) to be used by the receiver for channel estimation and fine synchronization, wherein each of the second training fields includes a respective first orthogonal frequency division multiplexing, OFDM, symbol, and wherein generating the PHY preamble includes inserting a respective first guard interval, GI, corresponding to each first OFDM symbol of the one or more second training fields; generating, at the communication device, i) a first portion of a PHY data payload of the PHY protocol unit, and ii) a second portion of the PHY data payload of the PHY protocol data unit, wherein the first portion of the PHY data payload and the second portion of the PHY data payload include a plurality of second OFDM symbols, wherein each of multiple second OFDM symbols among the plurality of second OFDM symbols has a first duration; and generating, at the communication device, a PHY midamble of the PHY protocol data unit, wherein: the PHY midamble is to be transmitted subsequent to transmission of the first portion of the PHY data payload and prior to transmission of the second portion of the PHY data payload, the PHY midamble is generated to include one or more third training fields (404-1, 404-M) to be used by the receiver for channel estimation and fine synchronization, each of the third training fields includes a respective third OFDM symbol having a second duration shorter than the first duration, and generating the PHY midamble includes inserting a respective second GI corresponding to each third OFDM symbol, wherein a duration of each first GI is equal to a duration of each second GI, wherein the PHY preamble (204; 300; 350) is generated to further include a subfield indicating the duration of both each first GI and each second GI. generating, at a communication device (114, 154-1, 154-2, 154-3), a physical layer, PHY, preamble (204; 300; 350) of a PHY protocol data unit, wherein the PHY preamble is generated to include i) a first training field to be used by a receiver (122, 162) for synchronization, and ii) one or more second training fields (336-1, 336-M) to be used by the receiver for channel estimation and fine synchronization, wherein each of the second training fields includes a respective first orthogonal frequency division multiplexing, OFDM, symbol, and wherein generating the PHY preamble includes inserting a respective first guard interval, GI, corresponding to each first OFDM symbol of the one or more second training fields; generating, at the communication device, i) a first portion of a PHY data payload of the PHY protocol unit, and ii) a second portion of the PHY data payload of the PHY protocol data unit, wherein the first portion of the PHY data payload and the second portion of the PHY data payload include a plurality of second OFDM symbols, wherein each of multiple second OFDM symbols among the plurality of second OFDM symbols has a first duration; and generating, at the communication device, a PHY midamble of the PHY protocol data unit, wherein: the PHY midamble is to be transmitted subsequent to transmission of the first portion of the PHY data payload and prior to transmission of the second portion of the PHY data payload, the PHY midamble is generated to include one or more third training fields (404-1, 404-M) to be used by the receiver for channel estimation and fine synchronization, each of the third training fields includes a respective third OFDM symbol having a second duration shorter than the first duration, and generating the PHY midamble includes inserting a respective second GI corresponding to each third OFDM symbol, wherein a duration of each first GI is equal to a duration of each second GI, the PHY midamble is to be transmitted subsequent to transmission of the first portion of the PHY data payload and prior to transmission of the second portion of the PHY data payload, the PHY midamble is generated to include one or more third training fields (404-1, 404-M) to be used by the receiver for channel estimation and fine synchronization, each of the third training fields includes a respective third OFDM symbol having a second duration shorter than the first duration, and generating the PHY midamble includes inserting a respective second GI corresponding to each third OFDM symbol, wherein a duration of each first GI is equal to a duration of each second GI, wherein the PHY preamble (204; 300; 350) is generated to further include a subfield indicating the duration of both each first GI and each second GI.