In wireless communications, a first device may determine a channel bandwidth and a high efficiency long training field (HE-LTF) mode. The first device may generate an HE-LTF symbol by using an HE-LTF sequence corresponding to the determined channel bandwidth and HE-LTF mode. The first device may transmit, in the determined channel bandwidth, a high efficiency physical layer convergence procedure (PLCP) protocol data unit (HE PPDU) that includes the HE-LTF symbol. A second device may receive, in a channel bandwidth, a downlink HE PPDU that includes an HE-LTF symbol. The second device may obtain, from the HE-LTF symbol, an HE-LTF sequence corresponding to the channel bandwidth and an HE-LTF mode of the HE-LTF symbol. The downlink HE PPDU may be the HE PPDU from the first device. Other methods, apparatus, and computer-readable media are also disclosed.