阅读说明：本技术 基于可重构全向超表面的无线通信信道估计方法及系统 (Wireless communication channel estimation method and system based on reconfigurable omnidirectional super surface ) 是由 张雨童 邓若琪 张浩波 于 2021-09-03 设计创作，主要内容包括：本发明涉及一种基于可重构全向超表面的无线通信信道估计方法,方法包括：基站从码本中选择不同的码字对信号进行预编码,并发射；可重构全向超表面接收到预编码后的信号后,计算可重构全向超表面配置矩阵,将预编码后的信号进行反射或透射；用户接收到预编码后的信号后,对预编码后的信号进行合并；用户根据合并后的信号确定当前最优的预编码矩阵、可重构全向超表面配置矩阵以及合并矩阵；用户通过反馈链路将最优预编码矩阵和可重构全向超表面配置矩阵反馈给基站,从而估计出等效信道矩阵。本发明中的上述方法可对无线通信的信道矩阵进行估计。(The invention relates to a wireless communication channel estimation method based on a reconfigurable omnidirectional super surface, which comprises the following steps: the base station selects different code words from the codebook to precode and transmit the signals; after the reconfigurable omnidirectional super surface receives the precoded signals, a reconfigurable omnidirectional super surface configuration matrix is calculated, and the precoded signals are reflected or transmitted; after receiving the pre-coded signals, the users merge the pre-coded signals; the user determines a current optimal pre-coding matrix, a reconfigurable omnidirectional super-surface configuration matrix and a merging matrix according to the merged signals; and the user feeds the optimal precoding matrix and the reconfigurable omnidirectional super-surface configuration matrix back to the base station through a feedback link, so that an equivalent channel matrix is estimated. The method of the present invention can estimate the channel matrix of wireless communication.)

1. A reconfigurable omnidirectional super surface, comprising:

a plurality of metamaterial units; the metamaterial unit includes: tunable devices, metal sheets, and metamaterial media.

2. The reconfigurable omnidirectional super surface of claim 1, wherein the tunable device is a diode, a liquid crystal, or a ferrite.

3. A wireless communication channel estimation method based on a reconfigurable omnidirectional super surface is characterized by comprising the following steps:

the base station selects different code words from the codebook to pre-code the signal and transmits the pre-coded signal;

after the reconfigurable omnidirectional super surface receives the precoded signals, a reconfigurable omnidirectional super surface configuration matrix is calculated according to the code words at the reconfigurable omnidirectional super surface, and the precoded signals are reflected or transmitted;

after receiving the pre-coded signals, the users merge the pre-coded signals;

the user determines a current optimal pre-coding matrix, a reconfigurable omnidirectional super-surface configuration matrix and a merging matrix according to the merged signals;

and the user feeds the optimal precoding matrix and the reconfigurable omnidirectional super-surface configuration matrix back to the base station through a feedback link, so that an equivalent channel matrix is estimated.

4. The method of claim 3, wherein the equivalent channel matrix is a product of an optimal precoding matrix, a channel matrix from a base station to the reconfigurable omnidirectional super surface, an optimal reconfigurable omnidirectional super surface configuration matrix, a channel matrix from the reconfigurable omnidirectional super surface to a user, an optimal combining matrix, and five matrices.

5. A reconfigurable omni-directional super surface based wireless communication channel estimation system, the system comprising:

the system comprises a base station, a reconfigurable omnidirectional super surface and a user;

the base station is used for selecting different code words from the codebook to precode signals and transmitting the precoded signals;

the reconfigurable omnidirectional super surface is used for receiving the precoded signals, calculating a reconfigurable omnidirectional super surface configuration matrix according to the code words at the reconfigurable omnidirectional super surface, and reflecting or transmitting the precoded signals;

the user is used for merging the pre-coded signals after receiving the pre-coded signals;

the user is also used for determining a current optimal pre-coding matrix, a reconfigurable omnidirectional super-surface configuration matrix and a merging matrix according to the merged signals;

and the user is also used for feeding back the optimal precoding matrix and the reconfigurable omnidirectional super-surface configuration matrix to the base station through a feedback link, so as to estimate an equivalent channel matrix.

6. The system of claim 5, wherein the equivalent channel matrix is a product of an optimal precoding matrix, a channel matrix from a base station to the reconfigurable omnidirectional super surface, an optimal reconfigurable omnidirectional super surface configuration matrix, a channel matrix from the reconfigurable omnidirectional super surface to a user, an optimal combining matrix, and five matrices.

Technical Field

The invention relates to the technical field of communication, in particular to a wireless communication channel estimation method and system based on a reconfigurable omnidirectional super surface.

Background

The recent development of the hypersurface provides a promising approach for the capacity increase of the sixth generation mobile communication networks. The traditional reconfigurable intelligent super-surface RIS is an ultrathin surface comprising a plurality of sub-wavelength near-passive scattering units, has controllable electromagnetic characteristics and enables the propagation environment to be reconfigurable. However, conventional reflectance type RIS can only reflect signals to one side of the super surface, thereby limiting service coverage. In order to provide network services for users on both sides of the super surface, the invention considers a novel super surface, namely an omnidirectional reconfigurable intelligent super surface (IOS), so that signals reaching one side of the IOS can be simultaneously reflected/transmitted to the users on both sides of the super surface, thereby greatly widening the coverage range of the network services.

Since each IOS unit corresponds to an antenna element, as the number of elements increases, the elements of the channel matrix between the IOS and the base station/user also increase, making channel estimation particularly complex. At present, no work research is carried out on a channel estimation method and device based on a reconfigurable omnidirectional super surface.

Disclosure of Invention

The invention aims to provide a wireless communication channel estimation method and system based on a reconfigurable omnidirectional super surface, which reflect or transmit incident signals to any direction and estimate a channel matrix between an IOS and a base station/user.

In order to achieve the purpose, the invention provides the following scheme:

a reconfigurable omnidirectional super surface, the reconfigurable omnidirectional super surface comprising:

a plurality of metamaterial units; the metamaterial unit includes: tunable devices, metal sheets, and metamaterial media.

Optionally, the tunable device is a diode, a liquid crystal, or a ferrite.

The invention also provides a wireless communication channel estimation method based on the reconfigurable omnidirectional super surface, which comprises the following steps:

the base station selects different code words from the codebook to pre-code the signal and transmits the pre-coded signal;

after the reconfigurable omnidirectional super surface receives the precoded signals, a reconfigurable omnidirectional super surface configuration matrix is calculated according to the code words at the reconfigurable omnidirectional super surface, and the precoded signals are reflected or transmitted;

after receiving the pre-coded signals, the users merge the pre-coded signals;

the user determines a current optimal pre-coding matrix, a reconfigurable omnidirectional super-surface configuration matrix and a merging matrix according to the merged signals;

and the user feeds the optimal precoding matrix and the reconfigurable omnidirectional super-surface configuration matrix back to the base station through a feedback link, so that an equivalent channel matrix is estimated.

Optionally, the equivalent channel matrix is a product of an optimal precoding matrix, a channel matrix from the base station to the reconfigurable omnidirectional super-surface, an optimal reconfigurable omnidirectional super-surface configuration matrix, a channel matrix from the reconfigurable omnidirectional super-surface to the user, an optimal combining matrix, and five matrices.

The invention also provides a wireless communication channel estimation system based on the reconfigurable omnidirectional super surface, which comprises:

the system comprises a base station, a reconfigurable omnidirectional super surface and a user;

the base station is used for selecting different code words from the codebook to precode signals and transmitting the precoded signals;

the reconfigurable omnidirectional super surface is used for receiving the precoded signals, calculating a reconfigurable omnidirectional super surface configuration matrix according to the code words at the reconfigurable omnidirectional super surface, and reflecting or transmitting the precoded signals;

the user is used for merging the pre-coded signals after receiving the pre-coded signals;

the user is also used for determining a current optimal pre-coding matrix, a reconfigurable omnidirectional super-surface configuration matrix and a merging matrix according to the merged signals;

and the user is also used for feeding back the optimal precoding matrix and the reconfigurable omnidirectional super-surface configuration matrix to the base station through a feedback link, so as to estimate an equivalent channel matrix.

Optionally, the equivalent channel matrix is a product of an optimal precoding matrix, a channel matrix from the base station to the reconfigurable omnidirectional super-surface, an optimal reconfigurable omnidirectional super-surface configuration matrix, a channel matrix from the reconfigurable omnidirectional super-surface to the user, an optimal combining matrix, and five matrices.

According to the specific embodiment provided by the invention, the invention discloses the following technical effects:

the reconfigurable omnidirectional metamaterial unit is characterized in that a plurality of metamaterial units are arranged on a reconfigurable omnidirectional metamaterial surface; the metamaterial unit includes: the adjustable device, the metal sheet and the metamaterial medium can reflect or transmit an incident signal to any direction, the coverage range can reach 360 degrees, and the direction can be adjusted through software; after the reconfigurable omnidirectional super surface receives the precoded signals, a reconfigurable omnidirectional super surface configuration matrix is calculated according to the code words at the reconfigurable omnidirectional super surface, and the precoded signals are reflected or transmitted; after receiving the pre-coded signals, the users merge the pre-coded signals; the user determines a current optimal pre-coding matrix, a reconfigurable omnidirectional super-surface configuration matrix and a merging matrix according to the merged signals; the user feeds the optimal precoding matrix and the reconfigurable omnidirectional super-surface configuration matrix back to the base station through the feedback link, so that an equivalent channel matrix is estimated, and the blank in the prior art is made up.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without inventive exercise.

FIG. 1 is a schematic diagram of a reconfigurable omnidirectional super-surface according to an embodiment of the invention;

FIG. 2 is a flow chart of a wireless communication channel estimation method based on a reconfigurable omnidirectional super surface according to an embodiment of the present invention;

fig. 3 is a flowchart of a method for estimating a wireless communication channel based on a reconfigurable omnidirectional super surface according to an embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention aims to provide a wireless communication channel estimation method and a wireless communication channel estimation system based on a reconfigurable omnidirectional super surface, which are used for estimating a channel matrix between an IOS and a base station/user, wherein the IOS can reflect or transmit incident signals to any direction.

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.

Fig. 1 is a schematic diagram of a reconfigurable omnidirectional super-surface according to an embodiment of the present invention, as shown in fig. 1, the reconfigurable omnidirectional super-surface is formed by a plurality of metamaterial units, and can reflect or transmit an incident signal to any direction, and the coverage range can reach 360 °, so that the reconfigurable omnidirectional super-surface is called omni-directional, and at the same time, the direction can be adjusted by software (the direction of a conventional super-surface is fixed), so that the reconfigurable super-surface is called reconfigurable. The metamaterial unit is composed of a plurality of adjustable devices (PIN diodes)1, a metal sheet (patch)2, a metamaterial medium 3 and the like. The metamaterial means a material which does not exist in nature and is artificially composed, and the metamaterial in the present invention means an artificial electromagnetic material.

Based on the reconfigurable omnidirectional super surface, the invention provides a wireless communication channel estimation method based on the reconfigurable omnidirectional super surface.

Channel State Information (CSI): information used to estimate a communication link characteristic includes RI, PTI (Precoding Type Indicator), PMI, CQI. The process of estimating CSI is called channel estimation.

Wherein, ri (rank indication): the user suggests a transmission order to be used by the base station in the downlink transmission.

Pmi (precoding Matrix indicator): the user suggests a precoding matrix to be used by the base station in the downlink transmission. The precoding matrix is selected on the basis of an assumption that the "transmission order indicated by the reported RI" is used.

Cqi (channel Quality indicator): the user uses the CQI to tell the scheduler of the base station the downlink channel quality information the user sees.

Referring to fig. 2, fig. 2 is a flow chart of a wireless communication channel estimation method based on a reconfigurable omnidirectional super surface according to an embodiment of the present invention, where a channel matrix between a base station and a user is assumed to be H, and when the base station transmits a signal s to the user, a signal received by the user is y ═ Hs + n, where n represents noise. Can be converted into y ═ U ∑ C by singular value decomposition^HTs + n. At this time, we do not need to know the channel matrix, and only need to obtain the codebook C. The codebook can be obtained at both the base station and the user, and when the codebook is applied, a code word which can maximize the channel capacity is selected according to the PMI. As shown in the above figure, in the downlink, the base station (transmitting end) and the user (receiving end) select different codewords from the codebook to precode and combine signals, and the user determines the current optimal PMI according to the combined signals and feeds back the PMI to the transmitting end through the limited feedback link, thereby estimating the channel matrix H.

Referring to fig. 3, fig. 3 is a flowchart of a method for estimating a wireless communication channel based on a reconfigurable omnidirectional super surface according to an embodiment of the present invention, where the method includes:

step 101: and the base station selects different code words from the codebook to precode the signals and transmits the precoded signals.

Step 102: after the reconfigurable omnidirectional super surface receives the precoded signals, a reconfigurable omnidirectional super surface configuration matrix is calculated according to the code words at the reconfigurable omnidirectional super surface, and the precoded signals are reflected or transmitted.

Step 103: and after receiving the pre-coded signals, the users combine the pre-coded signals.

Step 104: and the user determines the current optimal pre-coding matrix, the reconfigurable omnidirectional super-surface configuration matrix and the combined matrix according to the combined signals.

Step 105: and the user feeds the optimal precoding matrix and the reconfigurable omnidirectional super-surface configuration matrix back to the base station through a feedback link, so as to estimate an equivalent channel matrix, wherein the equivalent channel matrix is the product of the optimal precoding matrix, a channel matrix from the base station to the reconfigurable omnidirectional super-surface, the optimal reconfigurable omnidirectional super-surface configuration matrix, a channel matrix from the reconfigurable omnidirectional super-surface to the user, an optimal combination matrix and five matrixes.

Corresponding to the method, the application aims at the reconfigurable omnidirectional super surface and also provides wireless communication channel estimation based on the reconfigurable omnidirectional super surface, and the system comprises the following steps:

the system comprises a base station, a reconfigurable omnidirectional super surface and a user;

the base station is used for selecting different code words from the codebook to precode signals and transmitting the precoded signals;

the reconfigurable omnidirectional super surface is used for receiving the precoded signals, calculating a reconfigurable omnidirectional super surface configuration matrix according to the code words at the reconfigurable omnidirectional super surface, and reflecting or transmitting the precoded signals;

the user is used for merging the pre-coded signals after receiving the pre-coded signals;

the user is also used for determining a current optimal pre-coding matrix, a reconfigurable omnidirectional super-surface configuration matrix and a merging matrix according to the merged signals;

the user is also used for feeding back the optimal precoding matrix and the reconfigurable omnidirectional super-surface configuration matrix to the base station through the feedback link, so that an equivalent channel matrix is estimated, wherein the equivalent channel matrix is the product of the optimal precoding matrix, a channel matrix from the base station to the reconfigurable omnidirectional super-surface, the optimal reconfigurable omnidirectional super-surface configuration matrix, a channel matrix from the reconfigurable omnidirectional super-surface to the user, an optimal combination matrix and five matrixes.

The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. For the system disclosed by the embodiment, the description is relatively simple because the system corresponds to the method disclosed by the embodiment, and the relevant points can be referred to the method part for description.

The principles and embodiments of the present invention have been described herein using specific examples, which are provided only to help understand the method and the core concept of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed. In view of the above, the present disclosure should not be construed as limiting the invention.