CN116388830A - Communication positioning integrated system and method based on intelligent reflecting surface - Google Patents

Communication positioning integrated system and method based on intelligent reflecting surface Download PDF

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CN116388830A
CN116388830A CN202310575497.9A CN202310575497A CN116388830A CN 116388830 A CN116388830 A CN 116388830A CN 202310575497 A CN202310575497 A CN 202310575497A CN 116388830 A CN116388830 A CN 116388830A
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communication
positioning
reflecting surface
reflection
intelligent
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吴亮
刘一非
张在琛
党建
朱秉诚
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Southeast University
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Southeast University
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/14—Relay systems
    • H04B7/15—Active relay systems
    • H04B7/155—Ground-based stations
    • H04B7/15528—Control of operation parameters of a relay station to exploit the physical medium
    • H04B7/1555—Selecting relay station antenna mode, e.g. selecting omnidirectional -, directional beams, selecting polarizations
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/0413—MIMO systems
    • H04B7/0456—Selection of precoding matrices or codebooks, e.g. using matrices antenna weighting
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W64/00—Locating users or terminals or network equipment for network management purposes, e.g. mobility management
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
    • Y02D30/00—Reducing energy consumption in communication networks
    • Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks

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Abstract

The invention discloses a communication positioning integrated system and a method based on an intelligent reflecting surface, wherein in a communication subframe, a transmitting end maps communication information into a control signal of the intelligent reflecting surface, and single-frequency carrier waves are subjected to phase modulation by utilizing the phase regulation capability of the intelligent reflecting surface to space electromagnetic waves, so that the high cost, high complexity and high energy consumption of the traditional mixer modulation are avoided; in a sensing positioning subframe, the reflecting surface reflects electromagnetic waves of different beam modes according to a preset codebook, the receiving end realizes frame synchronization and frequency offset correction according to a communication subframe of a protocol, and the cascade channel state information of a base station, the reflecting surface and a user is calculated according to the positioning codebook of the positioning subframe, so that the positioning information of the user is obtained through calculation, and is fed back through an uplink; the reflecting surface carries out narrow beam forming and positioning codebook optimization design on the user according to the feedback information, thereby improving the signal to noise ratio of communication, reducing the lower bound of the Kramer of positioning error and realizing the cooperative enhancement of the sense of unity.

Description

Communication positioning integrated system and method based on intelligent reflecting surface
Technical Field
The invention relates to the technical field of wireless communication and perception positioning, in particular to a communication positioning integrated system and method based on an intelligent reflecting surface.
Background
The fifth generation (5G) wireless network has achieved a 1000-fold increase in network capacity and a universal wireless connection goal of at least 4 hundred million devices thanks to support of various key technologies such as Ultra-dense network (UDN), massive multiple input multiple output (Multiple Input Multiple Output, MIMO), millimeter Wave (mmWave) communication, and the like. However, high complexity, hardware cost and increased power consumption remain unresolved key issues. For example, densely deploying base stations or access points in a UDN not only increases hardware overhead and maintenance costs, but also exacerbates network interference problems. How to provide reliable, scalable backhaul transport is a challenging task, especially in indoor deployments where there is no complete optical coverage. Furthermore, expanding massive MIMO from below 6GHz to mmWave bands generally requires more complex signal processing and more expensive and more energy consuming hardware. Thus, it is still imperative to study how to find innovative, spectrum and energy efficient and cost effective solutions for wireless networks beyond the future 5G.
The smart reflective surface (RIS) actively modifies the wireless channel between the reflective links by a highly controllable smart signal. By properly adjusting the 3D passive beamforming, the signal reflected by the reflecting surface can be constructively added with signals from other paths to enhance the desired signal power at the receiver or destructively cancel undesired signals such as co-channel interference, improving energy efficiency. The RIS-based communication system works in a short distance, so that the RIS-based communication system can be densely deployed, has expandability and low energy consumption, solves the problems of high complexity, high energy consumption, high hardware overhead and maintenance cost and aggravated network interference of the current communication system, and is an innovative, energy-saving, economical and efficient solution.
The intelligent reflective surface can reconfigure the wireless propagation environment by software controlled reflection, which overtakes the traditional way of modulating the baseband signal by the transmitter. In smart reflector systems, the incident excitation wave and reflection coefficient functions are very similar to the carrier and baseband signals of conventional communication systems. Under the guidance of modulation techniques in modern wireless communications, TDCIM-based systems have implemented various modulation schemes, and existing work has controlled intelligent reflective surface physical properties through software coding, implementing system level designs including Frequency Shift Keying (FSK), phase Shift Keying (PSK), and Quadrature Amplitude Modulation (QAM). More recently, more advanced systems incorporating Multiple Input Multiple Output (MIMO) technology have also been proposed.
In terms of positioning, the receiver is equipped with a hybrid architecture employing quantized beamforming in an RIS-based system. Unlike conventional multiple-input multiple-output (MIMO) systems, the design of channel estimation for RIS-based systems is challenging, as RIS is typically a passive array with limited signal processing capabilities. The application of the wireless communication system based on the intelligent super-surface assistance has a plurality of challenges, and a method for obtaining accurate position information of a user is required to be sought so as to assist in optimizing the reflection coefficient of the intelligent super-surface, so that the performance of the wireless communication system is improved, and the integration of the wireless communication and the sensing positioning assisted by the intelligent super-surface is realized.
Disclosure of Invention
The invention provides a communication positioning integrated system and method based on an intelligent reflecting surface, which are used for solving the problems of lower precision, higher power consumption cost, high complexity of hardware and algorithm and low functionality multiplexing of communication and positioning on a hardware architecture and algorithm system of the current indoor positioning system.
An embodiment of a first aspect of the present invention provides a communication positioning integrated system based on an intelligent reflection surface, where a communication protocol of the communication positioning integrated system is divided into a communication subframe and a positioning sensing subframe according to time, where the communication positioning integrated system includes:
a signal generator for transmitting a single frequency carrier;
comprising M x N reflecting units U m,n The intelligent reflecting surface is used for carrying out time division reflection phase modulation according to the frame structure of the protocol, reflecting signals to an air interface channel,the method comprises the steps of synchronously adjusting reflection phase coefficients of reflection units when a frame structure is a communication subframe, and adjusting reflection phase coefficients of different reflection units according to a preset codebook when the frame structure is a positioning sensing subframe;
the receiving end is used for carrying out frame synchronization and frequency offset correction according to the communication subframes of the reflected signals and the protocol, calculating the cascade channel state information of the communication positioning integrated system according to the preset codebook of the positioning sensing subframes, obtaining the positioning information of the receiving end, feeding back the positioning information to the intelligent reflecting surface through an uplink, enabling the intelligent reflecting surface to carry out narrow beam forming and precoding in the communication subframes according to the feedback information, and optimizing the reflection phase coefficient of the intelligent reflecting surface in the positioning sensing subframes.
Optionally, in an embodiment of the present invention, the reflection phase coefficient of the smart reflection surface is Γ m,n (t) the transmitting antenna of the signal generator transmitting a single frequency carrier wave
Figure BDA0004239883660000024
To a distance of +.>
Figure BDA0004239883660000021
Is a reflection unit U of m,n The light is reflected to an air interface channel through the intelligent reflecting surface and is separated from the reflecting unit U m,n Distance is->
Figure BDA0004239883660000022
The receiving antenna of the receiving end receives the cascade channel state information of the communication positioning integrated system is as follows:
Figure BDA0004239883660000023
where E represents the energy of the received signal,
Figure BDA0004239883660000031
is a transmitting antenna, a reflecting unit U m,n Combination normalized power radiation mode of receiving antenna of receiving end, lambda is carrier waveWavelength f c Is the carrier frequency.
Optionally, in an embodiment of the present invention, the phase sign of the smart reflecting surface is
Figure BDA0004239883660000032
Wherein N is loc 、N com Symbol number of the perceptual localization sub-frame, the communication sub-frame, respectively +.>
Figure BDA0004239883660000033
Reflection phase coefficient vector +.>
Figure BDA0004239883660000034
Optionally, in an embodiment of the present invention, in a communication subframe, phase coefficients of all reflection units of the intelligent reflection surface are kept consistent, the communication subframe includes a communication pilot symbol, and the receiving end is further configured to locally correlate a received signal according to a preset pilot, achieve synchronization of a frame start point, confirm a position of a sensing positioning subframe by the synchronization point, and perform frequency offset estimation and phase correction according to the preset pilot.
Optionally, in one embodiment of the present invention, in the communication subframe, the reflection phase coefficient Γ of the reflection unit is adjusted synchronously m,n (t) is:
Figure BDA0004239883660000035
wherein Γ is k For the kth reflection phase coefficient, T s For the symbol duration, R (t) is a rectangular pulse-shaped signal,
Figure BDA0004239883660000036
optionally, in one embodiment of the present invention, the combination of all reflection unit phase coefficients at each time in the location-aware subframe is the location-aware codebook at the current time, whereIn the above, each reflecting unit of the reflecting surface sets a reflecting unit phase coefficient Γ according to a preset codebook m,n (t) is:
Figure BDA0004239883660000037
optionally, in an embodiment of the present invention, the sampling symbols of the positioning sensing subframe received by the receiving end are:
Figure BDA0004239883660000041
wherein w [ k ]]Is Gaussian noise at the kth sampling time, Γ k For the diagonal matrix of the current location-aware codebook, H BR And H RU Channel state information vectors of base station end-smart reflector and smart reflector-receiver characterized by incident angle and exit angle, respectively, and H BR Is a known static channel vector;
Figure BDA0004239883660000042
Figure BDA0004239883660000043
wherein, the liquid crystal display device comprises a liquid crystal display device,
Figure BDA0004239883660000044
θ t 、/>
Figure BDA0004239883660000045
θ r azimuth and pitch angles from the smart reflecting surface to the signal generator and from the smart reflecting surface to the receiver, respectively.
Optionally, in an embodiment of the present invention, the relationship between the received signal vector of the receiving end and the unknown channel state information vector of the smart reflector-receiver and the calculation method of the channel state information vector of the smart reflector-receiver are:
Figure BDA0004239883660000046
Figure BDA0004239883660000047
wherein H is combine Is H BR And all sampling instants Γ k Is a representation of the concatenated channels of (c),
Figure BDA0004239883660000048
w is Gaussian white noise of the receiver, < >>
Figure BDA0004239883660000049
Is a least squares estimation of the intelligent reflector-receiver channel, the receiver is based on +.>
Figure BDA00042398836600000410
And knowing the coordinates of the base station, and calculating the self positioning position by using a MUSIC algorithm based on the feature space.
Optionally, in an embodiment of the present invention, the smart reflecting surface performs narrow beam forming and precoding in a communication subframe according to feedback information, and optimizes a reflection phase coefficient of the smart reflecting surface in a positioning sensing subframe, including:
the receiving end uses the self-positioning position coordinates and the channel state information vector of the intelligent reflecting surface-receiver
Figure BDA00042398836600000411
Reporting to the base station end through the uplink carrier frequency channel, so that the base station end can carry out the +_information according to the channel state information vector of the intelligent reflecting surface-receiver>
Figure BDA00042398836600000412
Precoding and narrowbeam reflection phase coefficients for intelligent reflective surfacesThe symbol of the phase coefficient of the reflecting unit of the intelligent reflecting surface after the forming and the pre-coding is as follows:
Figure BDA0004239883660000051
Wherein Q {.cndot. } represents the quantization of the ideal precoding value by the reflecting unit of the intelligent reflecting surface;
autocorrelation matrix of observation matrix by applying quasi-semi-positive rule
Figure BDA0004239883660000052
Performing optimization solution, and decomposing by adopting a frequency optimization algorithm based on a complete set of observation matrixes to obtain A opt The optimal phase of the positioning sensing subframe to the intelligent reflecting surface is calculated as follows:
Figure BDA0004239883660000053
an embodiment of a second aspect of the present invention provides a collaborative optimization method for a communication positioning integrated system based on an intelligent reflection surface, where the collaborative optimization method using the communication positioning integrated system based on an intelligent reflection surface described in the foregoing embodiment includes the following steps:
transmitting a single frequency carrier wave through a signal generator;
the method comprises the steps of carrying out reflection phase modulation on an intelligent reflection surface according to a frame structure of a protocol, and reflecting signals to an air interface channel, wherein reflection phase coefficients of reflection units are synchronously adjusted when the frame structure is a communication subframe, and reflection phase coefficients of different reflection units are adjusted according to a preset codebook when the frame structure is a positioning sensing subframe;
and carrying out frame synchronization and frequency offset correction according to the communication subframes of the reflected signals and the protocol, calculating the cascading channel state information of the communication and positioning integrated system according to the preset codebook of the positioning sensing subframes, obtaining the positioning information of a receiving end, and feeding back the positioning information to the intelligent reflecting surface through an uplink, so that the intelligent reflecting surface carries out narrow beam forming and precoding in the communication subframes according to the feedback information, and optimizing the reflection phase coefficient of the intelligent reflecting surface in the positioning sensing subframes.
According to the communication positioning integrated system and method based on the intelligent reflecting surface, in the communication subframe, the transmitting end maps communication information into the control signal of the intelligent reflecting surface, and the phase modulation capability of the intelligent reflecting surface to the space electromagnetic wave is utilized to carry out phase modulation on a single-frequency carrier wave, so that the high cost, high complexity and high energy consumption of the traditional mixer modulation are avoided; in a sensing positioning subframe, the reflecting surface reflects electromagnetic waves of different beam modes according to a preset codebook, the receiving end realizes frame synchronization and frequency offset correction according to a communication subframe of a protocol, and the cascade channel state information of a base station, the reflecting surface and a user is calculated according to the positioning codebook of the positioning subframe, so that the positioning information of the user is obtained through calculation, and is fed back through an uplink; the reflecting surface carries out narrow beam forming and precoding on the user according to the feedback information, thereby improving the signal to noise ratio of communication, reducing the lower bound of the Kramer of positioning error and realizing the cooperative enhancement of the sense of general.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
Drawings
The foregoing and/or additional aspects and advantages of the invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings, in which:
FIG. 1 is a schematic diagram of a communication positioning integrated system based on an intelligent reflecting surface according to an embodiment of the present invention;
fig. 2 is a schematic diagram of an application scenario of a communication perception integrated system based on an intelligent reflection surface according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of cascade channels and geometric positions of an intelligent reflection-surface-based communication perception integrated system under two-dimensional far-field conditions according to an embodiment of the present invention;
fig. 4 is a flowchart of a base station-user information exchange process provided according to an embodiment of the present invention;
fig. 5 is a schematic diagram of a phase setting frame structure of a base station side intelligent reflection surface according to an embodiment of the present invention;
FIG. 6 is a comparison of estimated errors before and after single RIS phase optimization provided in accordance with an embodiment of the present invention;
fig. 7 is a graph of achievable rate-SNR for system communications after beamforming for different schemes according to an embodiment of the invention;
fig. 8 is a flowchart of a collaborative optimization method of an intelligent reflector-based communication positioning integrated system according to an embodiment of the present invention.
Detailed Description
Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative and intended to explain the present invention and should not be construed as limiting the invention.
The following describes a communication positioning integrated system and a method based on an intelligent reflecting surface according to an embodiment of the invention with reference to the accompanying drawings. Aiming at the problems of lower precision, higher power consumption cost, high complexity of hardware and algorithm and low multiplexing of functions of communication and positioning on a hardware architecture and an algorithm system of the current indoor positioning system mentioned in the background center, the invention provides a communication positioning integrated system based on an intelligent reflecting surface, which utilizes the phase regulation capability of the intelligent reflecting surface to space electromagnetic waves to realize high-precision channel estimation and user perception positioning, optimizes the reflecting coefficient of the intelligent reflecting surface to improve the channel communication quality, reduces the Kramer lower bound of positioning errors and realizes the cooperative enhancement of the sense of unity.
Specifically, fig. 1 is a schematic structural diagram of a communication positioning integrated system based on an intelligent reflection surface according to an embodiment of the present invention.
As shown in fig. 1, a communication protocol of the integrated communication positioning system is divided into a communication subframe and a positioning sensing subframe according to time, and the integrated communication positioning system based on the intelligent reflection surface comprises: signal generation at base station sideThe device 100 and the reflection unit U including M×N m,n An intelligent reflecting surface 200 of (c), and a receiving end 300 on the user side.
A signal generator 100 for transmitting a single frequency carrier.
Comprising M x N reflecting units U m,n The intelligent reflecting surface 200 is configured to perform time-division reflection phase modulation according to a frame structure of a protocol, and reflect signals to an air interface channel, wherein when the frame structure is a communication subframe, reflection phase coefficients of reflecting units are synchronously adjusted, and when the frame structure is a positioning sensing subframe, reflection phase coefficients of different reflecting units are adjusted according to a preset codebook.
The receiving end 300 is configured to perform frame synchronization and frequency offset correction according to the communication sub-frame of the reflected signal and the protocol, calculate the cascading channel state information of the communication positioning integrated system according to the preset codebook of the positioning sensing sub-frame, obtain the positioning information of the receiving end, and feed back the positioning information to the intelligent reflecting surface through the uplink, so that the intelligent reflecting surface performs narrow beam forming and precoding in the communication sub-frame according to the feedback information, and optimize the reflection phase coefficient of the intelligent reflecting surface in the positioning sensing sub-frame.
In an embodiment of the invention, the perceived positioning of the user terminal and the enhancement of the downlink communication quality are realized based on the intelligent reflecting surface design. The system communication protocol is divided into a communication subframe Fcom and a positioning aware subframe Floc in time. In a communication subframe, the intelligent reflector synchronously modifies the reflection phase Γ of all reflector units mn (t) implementing signal modulation. In the positioning sensing subframe, the intelligent reflecting surface reflects the reflection phases Γ of different reflecting units according to a preset codebook mn (t) controlling, reflecting electromagnetic waves of different beam modes and receiving by a receiving end for signal processing. The receiving end realizes frame synchronization and frequency offset correction according to the communication subframe Fcom of the protocol, and calculates the cascading channel state information of the base station-reflecting surface-user (BS-RIS-UE) according to the positioning codebook of the positioning subframe Floc, thereby calculating and obtaining the positioning information of the user, and feeding back through an uplink. The reflecting surface carries out narrow beam forming and precoding on the user according to the feedback information, thereby improving the signal to noise ratio of communication, reducing the lower bound of the Kramer of the positioning error and realizingThe sense of general is integrally cooperated and enhanced.
In the all-in-one system, a base station transmits a single-frequency signal, an intelligent reflecting surface carries out time-division reflection phase modulation according to a frame structure, and the reflected signal is transmitted to an air interface channel. And the receiving end performs positioning sensing resolving and communication demodulation according to the reflected signal and the frame structure.
The channel model of the general sense integrated system specifically comprises the following steps: the base station transmitting end consists of a signal generator and an intelligent reflecting surface, wherein the intelligent reflecting surface is provided with M multiplied by N reflecting units U m,n The reflection coefficient signal is Γ m,n (t), the base station transmitting end BS and the user receiving end UE are both single antennas. With base station BS as origin of coordinates p BS ＝[0,0,0] T The RIS and UE coordinates are p respectively RIS ＝[x RIS ,y RIS ,z RIS ] T 、p UE ＝[x UE ,y UE ,z UE ] T . Transmitting antenna for transmitting single frequency carrier
Figure BDA0004239883660000074
To a distance of +.>
Figure BDA0004239883660000071
Is a reflecting surface unit U of m,n Is reflected to an empty channel by RIS and is separated from U m,n Distance is->
Figure BDA0004239883660000072
Is received by the user terminal antenna. The whole channel is a cascade channel of the BS-RIS-UE, and is specifically determined by the following formula:
Figure BDA0004239883660000073
wherein the energy of the transmitting antenna, the gain of the transmitter, the gain of the receiver and the gain of the RIS are respectively P t 、G t 、G r 、G。
Figure BDA0004239883660000081
Figure BDA00042398836600000816
From U respectively m,n Azimuth and pitch angle to the transmitter, from U m,n Azimuth, pitch to the receiver. d, d x 、d y 、λ、f c The lateral, longitudinal dimensions, carrier wavelength, carrier frequency of the RIS unit, respectively. />
Figure BDA0004239883660000083
Is a transmitting antenna, U m,n The combined normalized power radiation modes of the receiving antennas are as follows:
Figure BDA0004239883660000084
in the far field scene of the system, the equivalent baseband signal of the receiving end is determined specifically by the following formula:
Figure BDA0004239883660000085
wherein r is t 、r r The distance of the transmitter and receiver respectively from the center point of the RIS,
Figure BDA0004239883660000086
Respectively U m,n Compared to the deviation of the distance of the center point to the transmitter and receiver, namely:
Figure BDA0004239883660000087
Figure BDA0004239883660000088
Figure BDA0004239883660000089
θ t 、/>
Figure BDA00042398836600000810
θ r azimuth, pitch from the RIS to the transmitter and receiver, respectively. The energy of the received signal is denoted by E +.>
Figure BDA00042398836600000811
Can be expressed simply as:
Figure BDA00042398836600000812
the general sense integral frame structure is based on time division, and is divided into a communication subframe Fcom and a positioning sensing subframe Floc according to time, and specifically, the phase symbol of the intelligent reflecting surface is designed as follows
Figure BDA00042398836600000813
Wherein N is loc 、N com Symbol number of the perceptual localization sub-frame, the communication sub-frame, respectively +.>
Figure BDA00042398836600000814
Reflection phase coefficient vector +.>
Figure BDA00042398836600000815
In the communication subframe Fcom, all reflection units of the reflection surface keep consistent change at each moment so as to realize phase modulation and broadcast transmission of a single-frequency carrier. And the receiving end performs time domain timing synchronization, frequency offset calculation and correction according to the communication subframe.
In the communication sub-frame Fcom, all the elements of the reflective surface maintain a consistent phase change to achieve phase modulation of the carrier and reflection of the broadcast into the air channel. The communication sub-frame Fcom contains communication pilot frequency symbols, a receiving end carries out local correlation on the receiving signals according to preset pilot frequency, synchronization of a frame starting point is achieved, the synchronization point confirms the position of the perception positioning sub-frame Floc, and frequency offset estimation and phase correction are carried out according to the pilot frequency. Specifically, the reflection surface reflection system in communication subframe Fcom Number Γ m,n The setting of (t) is specifically determined by the following formula:
Figure BDA0004239883660000091
wherein Γ is k For the kth reflection phase coefficient, T s For the duration of the symbol, R (t) is a rectangular pulse-shaped signal, specifically,
Figure BDA0004239883660000092
in the positioning sensing subframe Floc, different reflection units of the reflection surface are set to different reflection phases at each moment so as to realize the transmission of electromagnetic waves with different beam modes according to a preset codebook. And the receiving end user determines the Floc position according to the frame timing synchronization result, calculates channel state information according to Floc and the codebook, and calculates a positioning sensing result.
In the positioning sensing subframe Floc, the units of the reflecting surface set reflection coefficients according to a preset codebook, and coefficients among the units are different so as to send electromagnetic waves of different beam modes. Specifically, the reflection coefficient Γ of the reflecting surface in the positioning sensing subframe Floc m,n The setting of (t) is specifically determined by the following formula:
Figure BDA0004239883660000093
all reflection units at each moment in Floc
Figure BDA0004239883660000094
The combination of which constitutes the location-aware codebook at the current time.
The sampling symbol of the Floc subframe received by the user receiving end is specifically determined by the following formula:
Figure BDA0004239883660000095
wherein w [ k ]]Is the kth sampling instantIs of Gaussian noise Γ k Is the diagonal matrix of the current codebook, namely:
Figure BDA0004239883660000096
wherein H is BR 、H RU BS-RIS and RIS-UE channel state information vectors characterized by incident angle and exit angle, respectively, and H BR H is a known static channel vector under far field assumption of the system BR And H RU Can be expressed as containing ginseng
Figure BDA0004239883660000097
And theta t 、
Figure BDA0004239883660000098
And theta r Form of Cronecker product, +.>
Figure BDA0004239883660000099
θ t 、/>
Figure BDA00042398836600000910
θ r Azimuth angle and pitch angle from RIS to transmitter, azimuth angle and pitch angle from RIS to receiver. Specifically, H BR 、H RU Is determined by the following formula:
Figure BDA0004239883660000101
Figure BDA0004239883660000102
the time signal of the user receiving end is expressed in a vector mode:
Figure BDA0004239883660000103
then the received signal vector and unknown channel H RU Relation of (c) and H RU Is calculated byIs determined by the following formula:
Figure BDA0004239883660000104
Figure BDA0004239883660000105
wherein H is combine Is H BR And all sampling instants Γ k Is represented by a cascade of channels, i.e. having
Figure BDA0004239883660000106
W is Gaussian white noise of the receiver, < >>
Figure BDA0004239883660000107
Is a least squares estimate of the RIS-UE channel. The user terminal is according to->
Figure BDA0004239883660000108
And knowing the coordinates of the base station, and calculating the self positioning position by using a MUSIC algorithm based on the feature space.
The user feeds back channel state information by using the uplink carrier frequency, and the base station end carries out narrow beam forming and precoding on the communication of the user in Fcom according to the feedback result, so that the signal-to-noise ratio and the channel capacity of the communication are improved; and (3) performing positioning codebook optimization design in the Floc, and realizing high-precision positioning through subsequent feedback iteration.
The user calculates the self-resolving coordinates and channel state information
Figure BDA0004239883660000109
Reporting to the base station end through an uplink carrier frequency channel. The base station is according to->
Figure BDA00042398836600001010
The reflection phase of RIS is pre-coded and shaped by narrow wave beam, and the reflection coefficient sign of RIS unit after pre-coding is determined by the following formula:
Figure BDA00042398836600001011
wherein the RIS reflection unit is subject to hardware conditions to achieve only a partially discrete reflection phase, Q {. Cndot. }, represents the quantization of the ideal precoding value by the RIS reflection unit. And carrying out wave beam forming on the Fcom and the Floc to improve the signal-to-noise ratio and the channel capacity of communication. And carrying out wave beam forming on Fcom to improve the signal-to-noise ratio and the channel capacity of communication, optimizing RIS phase coefficient in Floc by taking positioning error reduction as a target, and realizing high-precision positioning through subsequent feedback iteration.
In the positioning sensing subframe Floc, high-precision positioning is realized through subsequent feedback iteration. Since it has been predicted
Figure BDA00042398836600001012
As a result of estimation, in order to make the positioning accuracy higher and follow up the user UE position change in real time, the lower bound of Kramer in the estimation error is used as an optimization target to code book +_in Floc>
Figure BDA0004239883660000111
Is optimized.
Consider the RIS communication system model:
Figure BDA0004239883660000112
the beta represents the signal amplitude and the path loss, and the beta cannot be accurately calculated through the path loss because of the complex actual environment, so the beta is set to be unknown to be measured;
Figure BDA0004239883660000113
An unknown phase introduced by carrier recovery for the receiving end; h combine Is H BR And all sampling instants Γ k Can be transmitted through codebook Γ k Dynamic adjustment, which can be considered as for H RU Is indicated in the following by a simplification; h RU Is an unknown RIS-UE channel, which can be accessed by +.>
Figure BDA0004239883660000114
The expression is that:
Figure BDA0004239883660000115
H RU in the following, h is used for simplicity. All unknown parameter vectors are
Figure BDA0004239883660000116
The Fisher information matrix for estimating Θ is:
Figure BDA0004239883660000117
specifically, the method is determined by the following formula:
Figure BDA0004239883660000118
wherein w=a H A is the autocorrelation matrix of observation matrix a,
Figure BDA0004239883660000119
the positioning error lower bound can be expressed as:
Figure BDA00042398836600001110
then there are:
Figure BDA00042398836600001111
after having been estimated for the first time
Figure BDA0004239883660000121
After that, it is known->
Figure BDA0004239883660000122
Then, for the positioning codebook Γ k Optimizing and adjusting the observation matrix A to reduce the p +.>
Figure BDA0004239883660000123
The Clamerlo bounds of the subsequent iteration estimates. From the above derivation, the optimization variable is
Figure BDA0004239883660000124
For hardware reasons, the RIS unit symbol in the positioning subframe is QPSK symbol, thus |W ij |≤N loc 0.ltoreq.i, j.ltoreq.MN-1, the optimization problem can be expressed as:
Figure BDA0004239883660000125
s.t.|W ij |≤N loc
the problem is similar to the Semi-defined Program (SDP) problem and can be optimally solved by a CVX tool box.
Further, after the optimized autocorrelation matrix W is obtained opt ＝A H After A, it is necessary to make the W opt And (3) decomposing and solving an observation matrix A, wherein the characteristic of constant modulus and discrete phase of QPSK symbols in the A is limited, and the A is solved by adopting a frequency optimization algorithm based on a complete set of the observation matrix.
W opt Is N loc A at each moment t The sum of the autocorrelation matrices of =a (t,:), i.e. there is
Figure BDA0004239883660000126
Consider all possible phases of the observation matrix a +.>
Figure BDA0004239883660000127
Each of which is an observation vector A i ＝A all (i, i) all correspond to an autocorrelation matrix +.>
Figure BDA0004239883660000128
W is then opt Can use the prepared set R all Each element in (a) and the corresponding frequency p i To represent. There is an optimization problem:
Figure BDA0004239883660000129
s.t.0≤p(i)≤N loc
solving the frequency vector p through a CVX tool box, and sorting the p to obtain a larger frequency sum not exceeding N loc Can index the frequency of the observation matrix A after the optimization opt In the known BS-RIS static channel H BR The positioning subframe RIS optimization phase can be further solved:
Figure BDA00042398836600001210
the communication positioning integrated system based on the intelligent reflecting surface is described in the following by a specific embodiment.
Communication positioning integrated system design based on intelligent reflecting surface
The design and application scene of the communication positioning integrated system based on the intelligent reflecting surface are shown in fig. 2. The system comprises base station equipment BS, an intelligent reflection surface RIS and user terminals UE, wherein a line-of-sight link between the user UE and the base station BS is blocked by an obstacle, an AP transmits a single-tone signal, the single-tone signal is fed back to an air interface channel after being reflected and modulated by the RIS and is received by the UE, and the whole channel is a cascade channel formed by the AP-RIS-UE. The phase control signal of each reflection unit of the RIS can be changed integrally to realize communication modulation, and can also be set to different reflection phases so as to emit electromagnetic waves with different beam modes to realize positioning sensing. The two reflection phase setting signals are distributed according to the time division relationship to form a frame structure of RIS end phase signal setting.
With base station BS as origin of coordinates p BS ＝[0,0,0] T The RIS and UE coordinates are p RIS ＝[x RIS ,y RIS ,z RIS ] T 、p UE ＝[x UE ,y UE ,z UE ] T . The intelligent reflecting surface is provided with M multiplied by N reflecting units U m,n The reflection coefficient signal is Γ m,n (t), the base station transmitting end BS and the user receiving end UE are both single antennas. In this embodiment, the BS-RIS and RIS-UE channels are designed with far field in mind
Figure BDA00042398836600001315
From U respectively m,n Azimuth and pitch angle to the transmitter, from U m,n Azimuth, pitch to the receiver. Transmitting antenna transmitting single frequency carrier wave->
Figure BDA00042398836600001316
To a distance of +.>
Figure BDA0004239883660000133
Is a reflecting surface unit U of m,n Is reflected to an empty channel by RIS and is separated from U m,n Distance is->
Figure BDA0004239883660000134
Is received by the user terminal antenna. As shown in fig. 3, the entire channel is a concatenated channel of BS-RIS-UE, and is specifically determined by the following formula:
Figure BDA0004239883660000135
wherein the energy of the transmitting antenna, the gain of the transmitter, the gain of the receiver, and the gain of the RIS are respectively P t 、G t 、G r 、G。d x 、d y Lambda is the lateral, longitudinal dimensions, carrier wavelength of the RIS unit, respectively.
Figure BDA0004239883660000136
Is a transmitting antenna, U m,n The combined normalized power radiation modes of the receiving antennas are as follows:
Figure BDA0004239883660000137
in the far field scene of the system, the equivalent baseband signal of the receiving end is determined specifically by the following formula:
Figure BDA0004239883660000138
/>
wherein r is t 、r r The distance of the transmitter and receiver respectively from the center point of the RIS,
Figure BDA0004239883660000139
respectively U m,n Compared to the deviation of the distance of the center point to the transmitter and receiver, namely:
Figure BDA00042398836600001310
Figure BDA00042398836600001311
Figure BDA00042398836600001312
θ t 、/>
Figure BDA00042398836600001313
θ r Azimuth, pitch from the RIS to the transmitter and receiver, respectively. The energy of the received signal is denoted by E +.>
Figure BDA00042398836600001314
Can be expressed simply as:
Figure BDA0004239883660000141
as shown in fig. 4, the ventilation integrated frame structure is based on time division, and is divided into a communication subframe Fcom and a positioning sensing subframe Floc according to time, specifically, the phase symbol of the intelligent reflecting surface is designed as follows:
Figure BDA0004239883660000142
wherein N is loc 、N com The number of symbols of the perceptual positioning sub-frame and the communication sub-frame,
Figure BDA0004239883660000143
reflection phase coefficient vector +.>
Figure BDA0004239883660000144
(II) communication modulation scheme and receiving algorithm suitable for intelligent reflecting surface scene
As shown in fig. 5, in the communication subframe Fcom, all units of the reflection plane maintain a uniform phase change to achieve phase modulation of the carrier wave and reflection of the broadcast into the air channel. Specifically, the reflection coefficient Γ of the reflecting surface in the communication subframe Fcom m,n The setting of (t) is specifically determined by the following formula:
Figure BDA0004239883660000145
wherein Γ is k For the kth reflection phase coefficient, T s For symbol duration, R (t) is a rectangular pulse-shaping signal, specifically:
Figure BDA0004239883660000146
the communication subframe Fcom includes communication pilot symbols of two segments of length N PN A random sequence (Pseudo-Noise, PN) of=15, and specifically, the reflection coefficient corresponding to the PN sequence is set as:
Figure BDA0004239883660000147
The receiving end carries out sliding window cross-correlation on the down-conversion sampling symbol sym of the receiving signal according to the preset pilot frequency, so that synchronization of a frame starting point is realized, the Fcom synchronization point confirms the position of a perception positioning subframe Floc, and frequency offset estimation and phase correction are carried out according to the pilot frequency. Specifically, the synchronization of Fcom and Floc start point positions is specifically determined by the following formula:
Figure BDA0004239883660000148
ind loc ＝ind com -N loc
under the general hardware condition, a certain frequency deviation exists between the carrier waves of the receiver and the transmitter, which can lead to phase rotation of received symbols, and reduce communication and positioning performance. According to the scheme, frequency offset correction is carried out according to PN sequences at two ends in pilot frequency, and specifically, frequency offset calculation and phase correction are determined through the following formulas:
Figure BDA0004239883660000151
sym_adj[n]＝sym[n]·e j2πΔf·(n-1)
third, channel estimation and user perception positioning algorithm based on intelligent reflection surface multi-beam transmission
As shown in fig. 5, in the positioning sensing subframe Floc, the units of the reflection surface set reflection coefficients according to a preset codebook, and coefficients are different between the units to transmit electromagnetic waves of different beam patterns. Specifically, the reflection coefficient Γ of the reflecting surface in the positioning sensing subframe Floc m,n The setting of (t) is specifically determined by the following formula:
Figure BDA0004239883660000152
all reflection units at each moment in Floc
Figure BDA0004239883660000153
The combination of which constitutes the location-aware codebook at the current time.
Further, the sample symbol received by the user receiving end in the Floc subframe is specifically determined by the following formula:
Figure BDA0004239883660000154
wherein w [ k ]]Is Gaussian noise at the kth sampling instant Γ k Is the diagonal matrix of the current codebook, namely:
Figure BDA0004239883660000155
wherein H is BR 、H RU BS-RIS and RIS-UE channel state information vectors characterized by incident angle and exit angle, respectively, and H BR H is a known static channel vector under far field assumption of the system BR And H RU Can be expressed as containing ginseng
Figure BDA0004239883660000156
And theta t 、
Figure BDA0004239883660000157
And theta r Form of Cronecker product, +.>
Figure BDA0004239883660000158
θ t 、/>
Figure BDA0004239883660000159
θ r Azimuth angle and pitch angle from RIS to transmitter, azimuth angle and pitch angle from RIS to receiver. Specifically, H BR 、H RU Is determined by the following formula:
Figure BDA00042398836600001510
Figure BDA00042398836600001511
the time signal of the user receiving end is expressed in a vector mode:
Figure BDA0004239883660000161
then the received signal vector and unknown channel H RU Relation of (c) and H RU Is determined by the following formula:
Figure BDA0004239883660000162
Figure BDA0004239883660000163
wherein H is combine Is H BR And all sampling instants Γ k Is represented by a cascade of channels, i.e. having
Figure BDA0004239883660000164
W is Gaussian white noise of the receiver, < >>
Figure BDA0004239883660000165
Is a least squares estimate of the RIS-UE channel. The user terminal is according to->
Figure BDA0004239883660000166
And knowing the coordinates of the base station, calculating the self-positioning azimuth ++using the MUSIC algorithm based on the feature space>
Figure BDA0004239883660000167
Specifically, first, according to RIS-UE channel estimation vector +.>
Figure BDA0004239883660000168
Calculating an autocorrelation matrix:
Figure BDA0004239883660000169
And carrying out eigenvalue decomposition on the autocorrelation matrix R, and calculating eigenvalues and eigenvectors of the R, wherein the larger K eigenvalues and the smaller M-K eigenvalues respectively correspond to a signal subspace and a noise subspace.
Figure BDA00042398836600001610
R＝U S Σ S U S H +U N Σ N U N H
Making two-dimensional parameters
Figure BDA00042398836600001618
Change according to->
Figure BDA00042398836600001611
To calculate a spectral function, wherein
Figure BDA00042398836600001612
Peak value corresponding +.>
Figure BDA00042398836600001613
Namely +.>
Figure BDA00042398836600001614
Is used for the estimation of the estimated value of (a).
(IV) an RIS coefficient iterative optimization scheme based on a Keramelteon boundary and a signal-to-noise ratio:
the user calculates the self-resolving coordinates and channel state information
Figure BDA00042398836600001615
Reporting to the base station end through an uplink carrier frequency channel. In the communication frame Fcom, the base station is according to +.>
Figure BDA00042398836600001616
The reflection phase of the RIS is precoded and narrowbeam formed to maximize the communication signal-to-noise ratio and achievable rate. Specifically, the reflection coefficient sign of the pre-coded RIS unit is determined by the following formula:
Figure BDA00042398836600001617
wherein the RIS reflection unit is subject to hardware conditions to achieve only a partially discrete reflection phase, Q {. Cndot. }, represents the quantization of the ideal precoding value by the RIS reflection unit.
In the positioning aware subframe Floc, since it has been predicted
Figure BDA0004239883660000171
As a result of estimation, in order to make the positioning accuracy higher and follow up the user UE position change in real time, the lower bound of cladmerol in the estimation error is used as an optimization target to the codebook in Floc
Figure BDA0004239883660000172
Is optimized.
Consider the RIS communication system model:
Figure BDA0004239883660000173
the beta represents the signal amplitude and the path loss, and the beta cannot be accurately calculated through the path loss because of the complex actual environment, so the beta is set to be unknown to be measured;
Figure BDA0004239883660000174
an unknown phase introduced by carrier recovery for the receiving end; h combine Is H BR And all sampling instants Γ k Can be transmitted through codebook Γ k Dynamic adjustment, which can be considered as for H RU Is indicated in the following by a simplification; h RU Is an unknown RIS-UE channel, which can be accessed by +.>
Figure BDA00042398836600001711
The expression is that:
Figure BDA0004239883660000175
H RU in the following, h is used for simplicity. All unknown parameter vectors are
Figure BDA0004239883660000176
The Fisher information matrix for estimating Θ is:
Figure BDA0004239883660000177
specifically, the method is determined by the following formula:
Figure BDA0004239883660000178
wherein w=a H A is the autocorrelation matrix of observation matrix a,
Figure BDA0004239883660000179
the positioning error lower bound can be expressed as:
Figure BDA00042398836600001710
then there are:
Figure BDA0004239883660000181
after having been estimated for the first time
Figure BDA0004239883660000182
After that, it is known->
Figure BDA0004239883660000183
Then, for the positioning codebook Γ k Optimizing and adjusting the observation matrix A to reduce the p +.>
Figure BDA0004239883660000184
The Clamerlo bounds of the subsequent iteration estimates. From the above derivation, the optimization variables are knownIs that
Figure BDA0004239883660000185
For hardware reasons, the RIS unit symbol in the positioning subframe is QPSK symbol, thus |W ij |≤N loc 0.ltoreq.i, j.ltoreq.MN-1, the optimization problem can be expressed as:
Figure BDA0004239883660000186
s.t.|W ij |≤N loc
the problem is similar to the Semi-defined Program (SDP) problem and can be optimally solved by a CVX tool box.
After the optimized autocorrelation matrix W is obtained opt ＝A H After A, it is necessary to make the W opt And (3) decomposing and solving an observation matrix A, wherein the characteristic of constant modulus and discrete phase of QPSK symbols in the A is limited, and the A is solved by adopting a frequency optimization algorithm based on a complete set of the observation matrix.
W opt Is N loc A at each moment t The sum of the autocorrelation matrices of =a (t,:), i.e. there is
Figure BDA0004239883660000187
Consider all possible phases of the observation matrix a +.>
Figure BDA0004239883660000188
Each of which is an observation vector A i ＝A all (i, i) all correspond to an autocorrelation matrix +.>
Figure BDA0004239883660000189
W is then opt Can use the prepared set R all Each element in (a) and the corresponding frequency p i To represent. There is an optimization problem:
Figure BDA00042398836600001810
/>
s.t.0≤p(i)≤N loc
solving the frequency vector p through a CVX tool box, and sorting the p to obtain a larger frequency sum not exceeding N loc Can index the frequency of the observation matrix A after the optimization opt In the known BS-RIS static channel H BR The positioning subframe RIS optimization phase can be further solved.
Figure BDA00042398836600001811
On the basis of optimizing the RIS reflecting surface phase coefficient, high-precision positioning is realized through subsequent feedback iteration, so that cooperative enhancement of communication and perceived positioning is realized.
As can be seen from fig. 6 and fig. 7, the communication positioning integrated system based on the intelligent reflection surface according to the embodiment of the invention utilizes the phase regulation capability of the intelligent reflection surface to the space electromagnetic wave to realize high-precision channel estimation and user perception positioning, optimizes the reflection coefficient of the intelligent reflection surface to improve the channel communication quality, reduces the positioning error, and realizes the cooperative enhancement of the sense of unity.
According to the communication positioning integrated system based on the intelligent reflection surface, in the communication subframe, the single-frequency carrier is subjected to phase modulation by utilizing the phase regulation capability of the intelligent reflection surface to the space electromagnetic wave, so that the high cost, the high complexity and the high energy consumption of the traditional mixer modulation are avoided; in the sensing positioning subframe, the reflecting surface reflects electromagnetic waves of different beam modes according to a preset codebook, and the receiving end carries out high-precision estimation on the cascade channel state information of the base station, the reflecting surface and the user according to the positioning codebook of the positioning subframe, so that the positioning information of the user is obtained through calculation; the reflecting surface carries out narrow beam forming and positioning codebook optimization design on the user according to the channel state information, thereby improving the signal to noise ratio of communication, reducing the lower bound of the Kramer of positioning error and realizing the cooperative enhancement of the sense of unity. The method is based on the hardware architecture and the system algorithm of the same intelligent reflecting surface, utilizes accurate channel estimation and positioning results to enhance the signal-to-noise ratio of the communication link, can iteratively enhance the performance of positioning perception, and effectively realizes the integration of communication perception.
Next, a collaborative optimization method of the intelligent reflector-based communication positioning integrated system according to an embodiment of the invention is described with reference to the accompanying drawings.
Fig. 8 is a flowchart of a collaborative optimization method of an intelligent reflector-based communication positioning integrated system according to an embodiment of the present invention.
As shown in fig. 8, the collaborative optimization method of the intelligent reflection-surface-based communication positioning integrated system utilizes the intelligent reflection-surface-based communication positioning integrated system of the above embodiment, and the method includes the following steps:
in step S101, a single frequency carrier is transmitted by a signal generator.
In step S102, the intelligent reflection surface is subjected to reflection phase modulation according to the frame structure of the protocol, and the signal is reflected to the air interface channel, wherein the reflection phase coefficients of the reflection units are synchronously adjusted when the frame structure is a communication subframe, and the reflection phase coefficients of different reflection units are adjusted according to a preset codebook when the frame structure is a positioning sensing subframe.
In step S103, frame synchronization and frequency offset correction are performed according to the communication subframes of the reflected signal and the protocol, and the cascade channel state information of the communication positioning integrated system is calculated according to the preset codebook of the positioning sensing subframe, so as to obtain the positioning information of the receiving end, and the positioning information is fed back to the intelligent reflecting surface through the uplink, so that the intelligent reflecting surface performs narrow beam forming and precoding in the communication subframes according to the feedback information, and the reflection phase coefficient of the intelligent reflecting surface is optimized in the positioning sensing subframe.
It should be noted that the foregoing explanation of the embodiment of the integrated communication positioning system based on the intelligent reflecting surface is also applicable to the integrated communication positioning method based on the intelligent reflecting surface of this embodiment, and will not be repeated herein.
According to the communication positioning integrated method based on the intelligent reflection surface, which is provided by the embodiment of the invention, in a communication subframe, the phase modulation of a single-frequency carrier is carried out by utilizing the phase regulation and control capability of the intelligent reflection surface to the space electromagnetic wave, so that the high cost, the high complexity and the high energy consumption of the traditional mixer modulation are avoided; in the sensing positioning subframe, the reflecting surface reflects electromagnetic waves of different beam modes according to a preset codebook, and the receiving end carries out high-precision estimation on the cascade channel state information of the base station, the reflecting surface and the user according to the positioning codebook of the positioning subframe, so that the positioning information of the user is obtained through calculation; the reflecting surface carries out narrow beam forming and positioning codebook optimization design on the user according to the channel state information, thereby improving the signal to noise ratio of communication, reducing the lower bound of the Kramer of positioning error and realizing the cooperative enhancement of the sense of unity. The method is based on the hardware architecture and the system algorithm of the same intelligent reflecting surface, utilizes accurate channel estimation and positioning results to enhance the signal-to-noise ratio of the communication link, can iteratively enhance the performance of positioning perception, and effectively realizes the integration of communication perception.
In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or N embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.
Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "N" means at least two, for example, two, three, etc., unless specifically defined otherwise.
Any process or method descriptions in flow charts or otherwise described herein may be understood as representing modules, segments, or portions of code which include one or more executable instructions for implementing specific logical functions or steps of the process, and additional implementations are included within the scope of the preferred embodiment of the present invention in which functions may be executed out of order from that shown or discussed, including substantially concurrently or in reverse order from that shown or discussed, depending on the functionality involved, as would be understood by those reasonably skilled in the art of the embodiments of the present invention.

Claims (10)

1. The utility model provides a communication location integration system based on intelligent reflecting surface which characterized in that, communication protocol of communication location integration system divide into communication subframe and location perception subframe according to time, communication location integration system includes:
a signal generator for transmitting a single frequency carrier;
comprising M x N reflecting units U m,n The intelligent reflecting surface is used for carrying out time division reflection phase modulation according to a frame structure of a protocol and reflecting signals to an air interface channel, wherein the reflection phase coefficients of the reflecting units are synchronously adjusted when the frame structure is a communication subframe, and the reflection phase coefficients of different reflecting units are adjusted according to a preset codebook when the frame structure is a positioning sensing subframe;
The receiving end is used for carrying out frame synchronization and frequency offset correction according to the communication subframes of the reflected signals and the protocol, calculating the cascade channel state information of the communication positioning integrated system according to the preset codebook of the positioning sensing subframes, obtaining the positioning information of the receiving end, feeding back the positioning information to the intelligent reflecting surface through an uplink, enabling the intelligent reflecting surface to carry out narrow beam forming and precoding in the communication subframes according to the feedback information, and optimizing the reflection phase coefficient of the intelligent reflecting surface in the positioning sensing subframes.
2. The system of claim 1, wherein the smart reflective surface has a reflection phase coefficient Γ m,n (t) the transmitting antenna of the signal generator transmitting a single frequency carrier wave
Figure FDA0004239883650000011
To a distance of +.>
Figure FDA0004239883650000012
Is a reflection unit U of m,n The light is reflected to an air interface channel through the intelligent reflecting surface and is separated from the reflecting unit U m,n Distance is->
Figure FDA0004239883650000013
The receiving antenna of the receiving end receives the cascade channel state information of the communication positioning integrated system is as follows:
Figure FDA0004239883650000014
where E represents the energy of the received signal,
Figure FDA0004239883650000015
is a transmitting antenna, a reflecting unit U m,n The combination normalized power radiation mode of the receiving antenna of the receiving end, lambda is the carrier wave wavelength, f c Is the carrier frequency.
3. The system of claim 2, wherein the phase sign of the smart reflective surface is
Figure FDA0004239883650000016
Wherein N is loc 、N com Symbol number of the perceptual localization sub-frame, the communication sub-frame, respectively +.>
Figure FDA0004239883650000017
Reflection phase coefficient vector +.>
Figure FDA0004239883650000018
4. The system of claim 1, wherein in the communication sub-frame, phase coefficients of all reflection units of the intelligent reflection surface are kept consistent, the communication sub-frame includes communication pilot symbols, the receiving end is further configured to locally correlate the received signals according to a preset pilot, achieve synchronization of a frame start point, confirm a position of a perceived positioning sub-frame by the synchronization point, and perform frequency offset estimation and phase correction according to the preset pilot.
5. A system according to claim 3, characterized in that in a communication subframe the reflection phase coefficient Γ of the reflection unit is adjusted synchronously m,n (t) is:
Figure FDA0004239883650000021
wherein Γ is k For the kth reflection phase coefficient, T s For the symbol duration, R (t) is a rectangular pulse-shaped signal,
Figure FDA0004239883650000022
6. the system of claim 5, wherein the combination of all reflection unit phase coefficients at each time in the location-aware subframe is a location-aware codebook at the current time, and wherein each reflection unit of the reflection plane in the location-aware subframe has a reflection unit phase coefficient Γ set according to a preset codebook m,n (t) is:
Figure FDA0004239883650000023
7. the system of claim 6, wherein the sampling symbols of the positioning aware subframe received by the receiving end are:
Figure FDA0004239883650000024
wherein w [ k ]]Is Gaussian noise at the kth sampling time, Γ k For the diagonal matrix of the current location-aware codebook, H BR And H RU Channel state information vectors of base station end-smart reflector and smart reflector-receiver characterized by incident angle and exit angle, respectively, and H BR Is a known static channel vector;
Figure FDA0004239883650000025
Figure FDA0004239883650000026
wherein, the liquid crystal display device comprises a liquid crystal display device,
Figure FDA0004239883650000027
θ t 、/>
Figure FDA0004239883650000028
θ r azimuth and pitch angles from the smart reflecting surface to the signal generator and from the smart reflecting surface to the receiver, respectively.
8. The system of claim 7, wherein the relationship between the received signal vector at the receiving end and the unknown channel state information vector of the smart reflector-receiver and the channel state information vector of the smart reflector-receiver are calculated by:
Figure FDA0004239883650000031
Figure FDA0004239883650000032
wherein H is combine Is H BR And all sampling instants Γ k Is a representation of the concatenated channels of (c),
Figure FDA0004239883650000033
w is Gaussian white noise of the receiver, < >>
Figure FDA0004239883650000034
Is a least squares estimation of the intelligent reflector-receiver channel, the receiver is based on +.>
Figure FDA0004239883650000035
And knowing the coordinates of the base station, and calculating the self positioning position by using a MUSIC algorithm based on the feature space.
9. The system of claim 8, wherein the smart reflecting surface performs narrow beamforming and precoding in the communication subframe according to the feedback information, and optimizing the reflection phase coefficient of the smart reflecting surface in the positioning sensing subframe comprises:
the receiving end uses the self-positioning position coordinates and the channel state information vector of the intelligent reflecting surface-receiver
Figure FDA0004239883650000036
Reporting to the base station end through an uplink carrier frequency channel, so that the base station end can transmit the information vector according to the channel state of the intelligent reflecting surface-receiver
Figure FDA0004239883650000037
The reflection phase coefficient of the intelligent reflecting surface is precoded and shaped by narrow wave beams, and the symbol of the reflection unit phase coefficient of the intelligent reflecting surface after precoding is:
Figure FDA0004239883650000038
wherein Q {.cndot. } represents the quantization of the ideal precoding value by the reflecting unit of the intelligent reflecting surface;
autocorrelation matrix of observation matrix by applying quasi-semi-positive rule
Figure FDA0004239883650000039
Performing optimization solution, and decomposing by adopting a frequency optimization algorithm based on a complete set of observation matrixes to obtain A opt The optimal phase of the positioning sensing subframe to the intelligent reflecting surface is calculated as follows:
Figure FDA00042398836500000310
10. a collaborative optimization method of an intelligent reflection-surface-based communication positioning integrated system, using the intelligent reflection-surface-based communication positioning integrated system according to any one of claims 1 to 9, characterized in that the collaborative optimization method comprises the following steps:
Transmitting a single frequency carrier wave through a signal generator;
the method comprises the steps of carrying out reflection phase modulation on an intelligent reflection surface according to a frame structure of a protocol, and reflecting signals to an air interface channel, wherein reflection phase coefficients of reflection units are synchronously adjusted when the frame structure is a communication subframe, and reflection phase coefficients of different reflection units are adjusted according to a preset codebook when the frame structure is a positioning sensing subframe;
and carrying out frame synchronization and frequency offset correction according to the communication subframes of the reflected signals and the protocol, calculating the cascading channel state information of the communication and positioning integrated system according to the preset codebook of the positioning sensing subframes, obtaining the positioning information of a receiving end, and feeding back the positioning information to the intelligent reflecting surface through an uplink, so that the intelligent reflecting surface carries out narrow beam forming and precoding in the communication subframes according to the feedback information, and optimizing the reflection phase coefficient of the intelligent reflecting surface in the positioning sensing subframes.
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CN116996103A (en) * 2023-09-26 2023-11-03 华南理工大学 Intelligent reflecting surface auxiliary communication system and method with electromagnetic energy collection function
CN117177253A (en) * 2023-10-31 2023-12-05 北京交通大学 Intelligent super-surface tracking and coverage enhancing method and device

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CN116996103A (en) * 2023-09-26 2023-11-03 华南理工大学 Intelligent reflecting surface auxiliary communication system and method with electromagnetic energy collection function
CN116996103B (en) * 2023-09-26 2024-01-02 华南理工大学 Intelligent reflecting surface auxiliary communication system and method with electromagnetic energy collection function
CN117177253A (en) * 2023-10-31 2023-12-05 北京交通大学 Intelligent super-surface tracking and coverage enhancing method and device
CN117177253B (en) * 2023-10-31 2024-01-23 北京交通大学 Intelligent super-surface tracking and coverage enhancing method and device

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