Reconfigurable intelligent surface-assisted NOMA downlink low-power-consumption transmission method

Abstract

The invention discloses a reconfigurable intelligent surface assisted NOMA (Non-Orthogonal Multiple Access) downlink low-power transmission method. On the premise of ensuring the signal to interference plus noise power ratio requirement of the user, establishing an optimization problem of base station power distribution and RIS phase deviation; establishing a conversion relation between the powerdistribution coefficient and the RIS phase deviation factor by utilizing the characteristics of the optimization problem, and converting the original optimization problem into a pure phase deviation optimization problem; further simplifying the optimization problem by using a phase-by-phase rotation method, and solving the optimal phase offset of each iteration through a one-dimensional search andpenalty function method; and repeating iteration until the target function converges to obtain an optimal phase shift matrix of the RIS and a base station power distribution coefficient. Compared with a traditional orthogonal multiple access transmission scheme, an RIS-free transmission scheme, an RIS random phase offset transmission scheme and an RIS equal phase offset transmission scheme, the transmission method provided by the invention can significantly reduce the total emission power consumption of the system.

Description

technical field [0001] The invention relates to the technical field of reconfigurable smart surfaces in wireless communication, in particular to a non-orthogonal multiple access (NOMA) downlink low-power transmission method assisted by reconfigurable smart surfaces. Background technique [0002] The propagation environment of traditional wireless communication is random and uncontrollable, which will bring certain damage to information transmission. In recent years, with the development of artificial electromagnetic materials, reconfigurable smart surfaces (RIS) have been proposed, which can intelligently configure the wireless communication propagation environment, thereby significantly improving the performance of wireless communication networks. As a passive device, RIS does not have any signal processing capabilities. It only needs to configure its phase offset according to the channel characteristics to realize the adjustment of the wireless signal propagation direction...

AI Technical Summary

Problems solved by technology

[0003] In the emerging RIS-assisted NOMA downlink system, neither the traditional orthogonal multiple access transmission scheme nor the RIS-assisted transmission NOMA scheme can jointly take advantage of the advantages of RIS and NOMA in the system, and, for a simple RIS phase offset Design schemes, such as random phase design and equal phase design, cannot make full use of time-varying channel state information to intelligently configure the wireless transmission environment, and thus cannot maximize the advantages of RIS, which affects the power efficiency of RIS auxiliary systems

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