A method for wireless communications, comprising: generating a frame having one or more training fields with pilot symbols therein to be transmitted via one or more tones; determining the one or more tones based on a set of fixed tone locations defined for a given bandwidth; selecting tone locations for the one or more tones at one or more of the defined fixed tone locations within a resource unit; and outputting the frame for transmission; wherein the given bandwidth comprises 20 MHz and: for resource units of 26 or 52 tones, the fixed tone locations are selected from tone locations corresponding to tone indices ±10, ±22, ±36, ±48, ±62, ±76, ±90, ±102, and ±116; and for resource units of 106 or 242 tones, the fixed tone locations are selected from tone locations corresponding to tone indices ±22, ±48, ±90, and ±116; or wherein the given bandwidth comprises 40 MHz and: for resource units of 26 or 52 tones, the fixed tone locations are selected from tone locations corresponding to tone indices ±10, ±24, ±36, ±50, ±64, ±78, ±90, ±104, ±116, ±130, ±144, ±158, ±170, ±184, ±198, ±212, ±224, and ±238; and for resource units of 106, 242, or 484 tones, the fixed tone locations are selected from tone locations corresponding to tone indices ±10, ±36, ±78, ±104, ±144, ±170, ±212, and ±238; or wherein the given bandwidth comprises 80 MHz and: for resource units of 26 or 52 tones, the fixed tone locations are selected from tone locations corresponding to tone indices ±10, ±24, ±38, ±50, ±64, ±78, ±92, ±104, ±118, ±130, ±144, ±158, ±172, ±184, ±198, ±212, ±226, ±238, ±252, ±266, ±280, ±292, ±306, ±320, ±334, ±346, ±360, ±372, ±386, ±400, ±414, ±426, ±440, ±454, ±468, ±480, and ±494; for resource units of 106, 242, or 484 tones, the fixed tone locations are selected from tone locations corresponding to tone indices ±24, ±50, ±92, ±118, ±158, ±184, ±226, ±252, ±266, ±292, ±334, ±360, ±400, ±426, ±468, and ±494; and for resource units of 996 tones, the fixed tone locations are selected from tone locations corresponding to tone indices ±24, ±92, ±158, ±226, ±266, ±334, ±400, and ±468. generating a frame having one or more training fields with pilot symbols therein to be transmitted via one or more tones; determining the one or more tones based on a set of fixed tone locations defined for a given bandwidth; selecting tone locations for the one or more tones at one or more of the defined fixed tone locations within a resource unit; and outputting the frame for transmission; wherein the given bandwidth comprises 20 MHz and: for resource units of 26 or 52 tones, the fixed tone locations are selected from tone locations corresponding to tone indices ±10, ±22, ±36, ±48, ±62, ±76, ±90, ±102, and ±116; and for resource units of 106 or 242 tones, the fixed tone locations are selected from tone locations corresponding to tone indices ±22, ±48, ±90, and ±116; for resource units of 26 or 52 tones, the fixed tone locations are selected from tone locations corresponding to tone indices ±10, ±22, ±36, ±48, ±62, ±76, ±90, ±102, and ±116; and for resource units of 106 or 242 tones, the fixed tone locations are selected from tone locations corresponding to tone indices ±22, ±48, ±90, and ±116; or wherein the given bandwidth comprises 40 MHz and: for resource units of 26 or 52 tones, the fixed tone locations are selected from tone locations corresponding to tone indices ±10, ±24, ±36, ±50, ±64, ±78, ±90, ±104, ±116, ±130, ±144, ±158, ±170, ±184, ±198, ±212, ±224, and ±238; and for resource units of 106, 242, or 484 tones, the fixed tone locations are selected from tone locations corresponding to tone indices ±10, ±36, ±78, ±104, ±144, ±170, ±212, and ±238; for resource units of 26 or 52 tones, the fixed tone locations are selected from tone locations corresponding to tone indices ±10, ±24, ±36, ±50, ±64, ±78, ±90, ±104, ±116, ±130, ±144, ±158, ±170, ±184, ±198, ±212, ±224, and ±238; and for resource units of 106, 242, or 484 tones, the fixed tone locations are selected from tone locations corresponding to tone indices ±10, ±36, ±78, ±104, ±144, ±170, ±212, and ±238; or wherein the given bandwidth comprises 80 MHz and: for resource units of 26 or 52 tones, the fixed tone locations are selected from tone locations corresponding to tone indices ±10, ±24, ±38, ±50, ±64, ±78, ±92, ±104, ±118, ±130, ±144, ±158, ±172, ±184, ±198, ±212, ±226, ±238, ±252, ±266, ±280, ±292, ±306, ±320, ±334, ±346, ±360, ±372, ±386, ±400, ±414, ±426, ±440, ±454, ±468, ±480, and ±494; for resource units of 106, 242, or 484 tones, the fixed tone locations are selected from tone locations corresponding to tone indices ±24, ±50, ±92, ±118, ±158, ±184, ±226, ±252, ±266, ±292, ±334, ±360, ±400, ±426, ±468, and ±494; and for resource units of 996 tones, the fixed tone locations are selected from tone locations corresponding to tone indices ±24, ±92, ±158, ±226, ±266, ±334, ±400, and ±468. for resource units of 26 or 52 tones, the fixed tone locations are selected from tone locations corresponding to tone indices ±10, ±24, ±38, ±50, ±64, ±78, ±92, ±104, ±118, ±130, ±144, ±158, ±172, ±184, ±198, ±212, ±226, ±238, ±252, ±266, ±280, ±292, ±306, ±320, ±334, ±346, ±360, ±372, ±386, ±400, ±414, ±426, ±440, ±454, ±468, ±480, and ±494; for resource units of 106, 242, or 484 tones, the fixed tone locations are selected from tone locations corresponding to tone indices ±24, ±50, ±92, ±118, ±158, ±184, ±226, ±252, ±266, ±292, ±334, ±360, ±400, ±426, ±468, and ±494; and for resource units of 996 tones, the fixed tone locations are selected from tone locations corresponding to tone indices ±24, ±92, ±158, ±226, ±266, ±334, ±400, and ±468.