CROSS-REFERENCE TO RELATED APPLICATION

This application claims foreign priority benefits under 35 U.S.C. § 119 to Korean Patent Application No. 1020200184393 filed on Dec. 28, 2020, the content of which is hereby incorporated by reference in its entirety.

BACKGROUND

Embodiments of the inventive concept described herein relate to an integrated beamforming technology using intelligent reflecting surface (IRS) element allocation, and more particularly, relate to an integrated beamforming method for alternating phase shifts of an IRS and beamforming of a transmitter to maximize a minimum rate or a total rate.

It has become the era of extravagant data where demands for wireless communication systems naturally follow. Extensive research has been investigated through many attempts such as massive multiple-input multiple-output (MIMO) and millimeter wave communication. However, practical issues such as high power consumption and cost are still in demand.

To address such issues, recently, intelligent reflecting surface (IRS) has been a promising novel technology as a next generation wireless communication technology. The IRS is in the form of being equipped with a plurality of passive elements, each of which has the ability to independently shift the phase of impinging electromagnetic waves when reflected. The IRS may advantageously shift the wireless communication environment channel using such features. Furthermore, because of using passive elements without directly transmitting signals, the IRS has a great advantage in terms of power consumption and price. Such features have the possibility of going beyond the threshold of the existing technology.

The current situation of study on the IRS is in early stages. Research has been done for beamforming techniques for various goals. Herein, the ongoing beamforming research has a big limitation having high complexity to the point of being hard to be practically used. Most studies proceed with address issues using convex optimization techniques. This shows high performance, whereas this has high complexity proportional to the number of passive elements of the IRS. It is hard to use the IRS in reality because it is expected for the IRS to be installed in large units thanks to low power consumption or price.

SUMMARY

Embodiments of the inventive concept provide an integrated beamforming method for alternating phase shifts of an IRS and beamforming of a transmitter to maximize a minimum rate or a total rate and a system therefor.

According to an exemplary embodiment, an integrated beamforming method may include allocating passive elements of an intelligent reflecting surface (IRS) to each of receivers, setting phase shifts of the IRS, the passive elements of which are allocated to each of the receivers, and performing transmit beamforming using the set phase shifts of the IRS.

The integrated beamforming method may further include alternately repeating the allocating, the setting, and the performing to maximize a minimum rate or a total rate.

The setting may include setting the phase shifts of the IRS such that a channel from the IRS to each of the receivers performs constructive interference with a channel between a transmitter and each of the receivers.

The allocating may include allocating the passive elements to each of the receivers to maximize a minimum rate or a total rate.

The allocating may include allocating the passive elements to each of the receivers, such that a channel between a transmitter and the receivers and a beamformer gain are maximized.

The performing may include performing the transmit beamforming using an effective channel established by the set phase shifts of the IRS.

According to an exemplary embodiment, an integrated beamforming method may include allocating passive elements of an intelligent reflecting surface (IRS) to each of receivers to maximize a minimum rate or a total rate and performing transmit beamforming using the IRS, the passive elements of which are allocated to each of the receivers.

According to an exemplary embodiment, an integrated beamforming system may include an allocation unit that allocates passive elements of an intelligent reflecting surface (IRS) to each of receivers, a setting unit that sets phase shifts of the IRS, the passive elements of which are allocated to each of the receivers, and a beamforming unit that performs transmit beamforming using the set phase shifts of the IRS.

The operations of the allocation unit, the setting unit, and the beamforming unit may be alternately repeated to maximize a minimum rate or a total rate.

The setting unit may set the phase shifts of the IRS such that a channel from the IRS to each of the receivers performs constructive interference with a channel between a transmitter and each of the receivers.

The allocation unit may allocate the passive elements to each of the receivers to maximize a minimum rate or a total rate.

The allocation unit may allocate the passive elements to each of the receivers, such that a channel between a transmitter and the receivers and a beamformer gain are maximized.

The beamforming unit may perform the transmit beamforming using an effective channel established by the set phase shifts of the IRS.

