Binning-based transmit beamforming for wireless communication systems

#The present disclosure relates generally to wireless communication devices, and in particular, to binning-based transmit beamforming for wireless communication systems.

#In wireless communications, such as Bluetooth, each connection event starts with a master device transmitting and a slave device receiving. Then, it continues with the slave device transmitting and the master device receiving. Due to this standardized transmit-receive order for the master and slave devices, transmit (Tx) beamforming is hampered by the difficulty of obtaining an up-to-date beamforming vector at the master device. In particular, the master device can estimate the beamforming vector while receiving a packet with a known preamble from the slave device. Since the master device transmits first and subsequently receives, the most recent beamforming vector is not available at the master device during a Tx beamforming in a transmit time slot. In fact, the most recent estimate of the beamforming vector is available at the master device in the following receive time slot when Tx beamforming is completed.

#Certain features of the subject technology are set forth in the appended claims. However, for purpose of explanation, several embodiments of the subject technology are set forth in the following figures.

#Certain features of the subject technology are set forth in the appended claims. However, for purpose of explanation, one or more implementations of the subject technology are set forth in the following figures.

#FIG. 1 is a diagram illustrating wireless communication system in accordance with one or more implementations.

#The detailed description set forth below is intended as a description of various configurations of the subject technology and is not intended to represent the only configurations in which the subject technology may be practiced. The appended drawings are incorporated herein and constitute a part of the detailed description. The detailed description includes specific details for the purpose of providing a thorough understanding of the subject technology. However, the subject technology is not limited to the specific details set forth herein and may be practiced using one or more implementations. In one or more instances, structures and components are shown in block diagram form in order to avoid obscuring the concepts of the subject technology.

#In one traditional approach to Tx beamforming, a receiver estimates a beamforming vector and sends it back to a transmitter. However, this approach incurs high communication overhead. In another traditional approach, a transmitter assumes channel reciprocity and uses received preambles from a receiver to calculate beamforming weights on the same channel. In still another approach, a transmitter applies a most recent beamforming vector by reusing the beamforming weights estimated from a last reception on a same hopping channel. However, the channel coherence time, in which the channel is considered to be not varying, is inherently a limiting factor to use previously estimated beamforming vectors on a current hopping channel. For example, Bluetooth is a frequency-hopping-based system. If the return time to the same hopping channel is greater than the channel coherence time, a previous estimate of the beamforming vector is likely to be outdated for purposes of being used on the current hopping channel. Using outdated beamforming weights can cause major performance degradation with respect to the case of applying the most recent beamforming vector.

#In Bluetooth, the master device always transmits first before receiving a packet from the slave device. The master device cannot receive a training sequence/preamble from the slave device on the current hopping channel to estimate the beamforming vector before starting transmit beamforming. Therefore, the traditional approaches discussed above are not directly applicable for the master device to obtain most recent beamforming vector estimate prior to beamforming.