Multi-user mimo uplink energy efficiency and spectrum efficiency joint optimization method assisted by intelligent reflector

Abstract

The invention proposes a multi-user MIMO uplink energy efficiency and spectrum efficiency joint optimization method assisted by an intelligent reflection surface. In this method, the signal sent by the user is reflected by the IRS and received by the base station, and the reflection unit of the IRS can change the phase of the incident signal. The present invention utilizes part of the channel state information, and considers two different situations in which the IRS reflection coefficient can take continuous values ​​and discrete values, through alternate optimization methods, deterministic equivalence principles, quadratic penalty methods, MM methods, and accelerated projection gradient descent, etc. method, jointly design the precoding matrix of each user and the reflection coefficient of IRS to maximize the weighted sum of energy efficiency and spectral efficiency. When the channel state information changes, the central controller dynamically implements the multi-user MIMO uplink transmission power allocation and IRS reflection coefficient adjustment for joint optimization of energy efficiency and spectrum efficiency. The invention has low implementation complexity, can effectively improve the energy efficiency and spectrum efficiency of multi-user MIMO uplink communication, and realize the balance between the two.

Description

technical field [0001] The invention belongs to the communication field, and in particular relates to a multi-user MIMO uplink energy and spectrum efficiency joint optimization method assisted by an intelligent reflection surface using partial channel state information. Background technique [0002] Intelligent Reflecting Surface (IRS) is a programmable surface composed of passive reflection units. By controlling the shape, size and direction of the reflection elements, each reflection unit can independently change the direction of the incident signal. phase or magnitude. [0003] In the IRS-assisted wireless communication system, an IRS is added between the sending end and the receiving end, and the signal sent by the sending end is reflected by the IRS and reaches the receiving end. Each element of the IRS independently changes the phase or amplitude of the incident signal, thus intelligently reconfiguring the wireless propagation environment, thereby significantly improv...

AI Technical Summary

Problems solved by technology

Traditional wireless transmission method design is usually based on instantaneous channel state information, but in scenarios such as high mobility, it is difficult to obtain instantaneous channel state information, so the present invention provides an IRS-assisted multi-user MIMO uplink based on partial channel state information transmission method

For the optimization problem of maximizing the weighted sum of energy efficiency and spectral efficiency, since the objective function is non-convex and the constraints of the IRS reflection coefficient are also non-convex, it is usually difficult to solve

In addition, the objective function needs to be expected. When the number of IRS reflection units is large, the computational complexity is very high

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