Beam change and smoothing in mixed mode WLAN systems

A first wireless communication device, comprising:

• a physical layer device configured to generate a data packet having a mixed mode preamble, wherein
• the mixed mode preamble includes (i) a first portion to be transmitted omnidirectionally via a single stream, and (ii) a second portion to be transmitted in a beamformed manner via a single stream or multiple streams,
• the mixed mode preamble includes a signal field corresponding to information about the data packet, and
• the signal field includes (i) a first sub-field that indicates a number of streams of the second portion of the mixed mode preamble and (ii) a second sub-field configured to selectively indicate, based on the first sub-field, (a) whether to perform a beam change between the first portion and the second portion of the mixed mode preamble and (b) whether to perform channel smoothing on the second portion of the mixed mode preamble,
• wherein the first-sub field controls which of (a) and (b) is indicated by the second sub-field, such that the second sub-field indicates whether to perform the beam change when the first sub-field corresponds to a first number of streams, and the second sub-field indicates whether to perform the channel smoothing when the first sub-field corresponds to a second number of streams;
• and
• a transceiver configured to transmit, from the first wireless communication device to a second wireless communication device, the data packet having the mixed mode preamble.