BACKGROUND

The present disclosure relates generally to wireless communication, and, more particularly, to a system and a method for enabling beamforming in wireless networks.

In wireless networks, wireless devices implement beamforming to improve quality (i.e., energy level) of wireless signals communicated therebetween. Examples of such wireless devices can include an access point (AP), a wireless client (e.g., a mobile device), or the like. A wireless device transmitting the wireless signals is referred to as a beamformer, and a wireless device receiving the wireless signals is referred to as a beamformee. When the beamformer is an AP, the beamformee can be a wireless client. Alternatively, when the beamformer is a wireless client, the beamformee can be an AP. The beamformer generates a steering matrix to enable the beamforming with the beamformee (i.e., to beamform the wireless signals to the beamformee). To generate the steering matrix, channel state information of a channel between the beamformer and the beamformee is required. To obtain the channel state information, the beamformer generates and transmits a null data packet (NDP) to the beamformee. The NDP includes various long training fields (LTFs) that assist the beamformee in estimating the channel state information.

Typically, a number of LTFs in the NDP is equal to a number of antennas of the beamformer. A signal-to-noise ratio associated with the beamformee is determined based on the number of LTFs in the NDP, and improves with an increase in the number of LTFs. Thus, to improve a beamforming performance of the beamformer, the beamformer generates the NDP having the number of LTFs greater than the number of antennas. In such a scenario, the NDP further has a status bit indicating that the number of LTFs in the NDP is greater than the number of antennas. The status bit is included in a high-efficiency signaling (HE-SIG) field of the NDP. Such a status bit is absent in the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard. Thus, utilization of the status bit limits the implementation of such a beamforming technique for the IEEE 802.11 standard. Therefore, there exists a need for a technical solution that solves the aforementioned problem of existing beamforming techniques.

SUMMARY

In an embodiment of the present disclosure, a beamformer is disclosed. The beamformer can include a plurality of antennas and a processing circuit that can be coupled with the plurality of antennas and a beamformee. The processing circuit can be configured to generate a null data packet (NDP). The NDP can include a plurality of long training fields (LTFs). A first count of the plurality of LTFs can be greater than a second count of the plurality of antennas. The NDP can be generated based on a spatial mapping matrix that is a product of first and second matrices. The first matrix can have a number of rows equal to the second count, and a number of columns equal to the first count. The second matrix can have a number of rows and a number of columns equal to the first count. The processing circuit can be further configured to transmit, using the plurality of antennas, the NDP to the beamformee to enable beamforming between the beamformer and the beamformee.

In another embodiment of the present disclosure, a beamforming method is disclosed. The beamforming method can include generating an NDP by a beamformer. The NDP can include a plurality of LTFs. A first count of the plurality of LTFs can be greater than a second count of a plurality of antennas of the beamformer. The NDP is generated based on a spatial mapping matrix that is a product of first and second matrices. The first matrix can have a number of rows equal to the second count, and a number of columns equal to the first count. The second matrix can have a number of rows and a number of columns equal to the first count. The beamforming method can further include transmitting the NDP by the beamformer to a beamformee using the plurality of antennas to enable beamforming therebetween.

In some embodiments, the first matrix can correspond to a first submatrix of a first orthogonal matrix. The first orthogonal matrix can have a number of rows and a number of columns equal to the first count. The second matrix can correspond to a second orthogonal matrix.

In some embodiments, the NDP can further include a signal field that can be indicative of a number of spatial time streams associated with the beamformer. The number of spatial time streams can be equal to the first count.

In some embodiments, the processing circuit can be further configured to generate a steering matrix associated with the beamformee based on a feedback matrix. The feedback matrix can be generated by the beamformee. Further, the feedback matrix can be indicative of channel state information associated with a channel between the beamformer and the beamformee. The processing circuit can be further configured to transmit, based on the steering matrix and using the plurality of antennas, a set of wireless signals to the beamformee, thereby enabling beamforming between the beamformer and the beamformee.

In some embodiments, the processing circuit can be further configured to receive a compressed feedback matrix from the beamformee, and process the compressed feedback matrix to regenerate the feedback matrix.

In some embodiments, the processing circuit can be further configured to receive the feedback matrix from the beamformee.

In some embodiments, the processing circuit can be further configured to generate an NDP announcement (NDPA) frame. The NDPA frame can include an index value that can be indicative of a number of columns to be included in the feedback matrix. Further, the index value can be equal to one of the first and second counts. The processing circuit can be further configured to transmit, using the plurality of antennas, the NDPA frame to the beamformee. The processing circuit transmits the NDPA frame to the beamformee prior to the transmission of the NDP to the beamformee.

In some embodiments, the first matrix can include second and third submatrices that can correspond to a first identity matrix and a null matrix, respectively. The first identity matrix can have a number of rows and a number of columns equal to the second count. The null matrix can have a number of rows equal to the second count, and a number of columns equal to a difference between the first and second counts.

In some embodiments, the steering matrix can correspond to a fourth submatrix of the feedback matrix. The fourth submatrix can have a number of rows and a number of columns equal to the second count.

In some embodiments, the first matrix can include fifth and sixth submatrices. The fifth submatrix can correspond to a product of a first phasor value and a second identity matrix. The second identity matrix can have a number of rows and a number of columns equal to the second count. Further, the sixth submatrix can correspond to a product of a second phasor value and a third identity matrix. The third identity matrix can have a number of rows and a number of columns equal to the second count.

In some embodiments, to generate the steering matrix, the processing circuit can be further configured to extract seventh and eighth submatrices from the feedback matrix such that a number of rows and a number of columns of each submatrix of the seventh and eighth submatrices is equal to the second count. The processing circuit can be further configured to generate a ninth submatrix based on the eighth submatrix and the first and second phasor values. The processing circuit can be further configured to combine the seventh and ninth submatrices to generate the steering matrix.

Various embodiments of the present disclosure disclose a beamformer that can include multiple antennas and a processing circuit. The processing circuit can generate an NDP that includes various LTFs. A number of LTFs in the NDP can be greater than a number of antennas of the beamformer. The NDP can be generated based on a spatial mapping matrix. The spatial mapping matrix can be a product of two matrices. One matrix can have a number of rows equal to the number of antennas of the beamformer, and a number of columns equal to the number of LTFs in the NDP. The other matrix can have a number of rows and a number of columns equal to the number of LTFs in the NDP. The processing circuit can transmit the NDP to a beamformee. The NDP is transmitted to the beamformee to obtain channel state information associated with a channel between the beamformer and the beamformee. The channel state information can be then utilized by the processing circuit to generate a steering matrix associated with the beamformee. Based on the steering matrix, the processing circuit can beamform (i.e., generate and transmit) various wireless signals to the beamformee, thereby enabling beamforming between the beamformer and the beamformee.

Thus, in a beamforming technique implemented by the beamformer of the present disclosure, the number of LTFs in the NDP is greater than the number of antennas of the beamformer. Further, a number of spatial time streams associated with the beamformer is equal to the number of LTFs as opposed to being equal to the number of antennas in a conventional beamforming technique. Based on the LTFs and the spatial time streams associated with the beamformer, the beamformee generates the feedback matrix. Thus, a need to transmit a status bit to the beamformee to indicate that the number of LTFs in the NDP is greater than the number of antennas of the beamformer, is eliminated. In other words, the beamforming technique of the present disclosure is implemented exclusively by utilizing the LTFs and the spatial time streams which are a part of the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard. Thus, the beamforming technique of the present disclosure can be implemented for the IEEE 802.11 standard.

