Patent ID: 9559760
Date: 2017-01-31
CPC Classifications: H04B,H04L,H04W,Y02D

Claim:
1. A method for requesting channel information, comprising: transmitting, by a beamformer, a null data packet announcement (NDPA) and a null data packet (NDP) within a duration of a current first transmission opportunity (TXOP) to enable one or more beamformees to estimate channel information; and when the duration of the current first TXOP is insufficient for the beamformer to receive channel information of at least one beamformee and the beamformer obtains a second TXOP, transmitting, by the beamformer, a channel information indication frame to the at least one beamformee within a duration of the second TXOP, to request the channel information of the at least one beamformee.