RIS-assisted multi-user millimeter wave MIMO system channel estimation method

Abstract

The invention discloses a channel estimation method of a reconfigurable intelligent surface (RIS)-assisted multi-user millimeter wave MIMO system. The invention provides a dynamic path number modeling and a compressed sensing algorithm for solving the problem of insufficient channel estimation precision caused by the path number between a fixed user and an RIS in the prior art. The method comprises the following steps: firstly, establishing a channel model, setting the number of paths between a user and an RIS as a random value within a certain range, and converting a channel into an angular domain cascade channel; then, pilot frequency is sent, and a received pilot frequency signal is converted to an angular domain; analyzing the row and column structure characteristics of the sparsity of the angular domain cascade channel; and according to an analysis result, designing a multi-user joint correlation competition algorithm: constructing an extended sensing matrix and a multi-user joint observation signal matrix, iteratively selecting non-zero row and non-zero column support, and estimating a channel by using a least square method. Compared with the prior art, the method has higher precision under the condition of the same pilot frequency overhead and the same signal-to-noise ratio.

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