An Indoor WiFi Signal Tracking Enhancement System and Method Based on Active RIS

Abstract

This invention discloses an indoor WiFi signal tracking and enhancement system based on an active RIS (Radio Reflector Array), comprising a controllable directional antenna array and a router. The router is placed in the center of the controllable directional antenna array, and the controllable directional antenna array beamforms the electromagnetic waves emitted by the router. The method for enhancing indoor WiFi signals using this system includes the following steps: (1) a mobile terminal emits a signal; (2) sensing units on the RIS in each room receive the signal and perform positioning; (3) the communication status is judged and classified; (4) the signal is amplified and accurately tracked to the communication equipment in the room, performing secondary beamforming of the WiFi signal. The active RIS of this invention can reflect and amplify the incoming wave signal, providing a certain gain effect on the signal emitted by the WiFi router, thus better ensuring the strength of the communication signal.

Description

Technical Field

[0001] This invention belongs to the field of RIS-assisted wireless communication technology, and relates to an indoor WiFi signal tracking and enhancement system and method based on active RIS. Background Technology

[0002] With the arrival of the 6G era, the number of home communication devices is increasing exponentially. The highly developed internet has led to higher demands for communication speed and quality in home communication devices. WiFi, as a mature technology in wireless local area networks, is widely used in home communication scenarios, offering advantages in flexibility and portability compared to the complex wired interface technology that connects devices via network cables. However, WiFi signals have weak wall penetration capabilities at their operating frequencies. To address the challenge of achieving full-house WiFi coverage, reconfigurable smart metasurface (RIS) technology has been proposed. A smart metasurface is an artificially constructed two-dimensional electromagnetic metamaterial composed of multiple tunable passive reflective units. It can change the phase, amplitude, frequency, polarization, and other electromagnetic characteristics of incident electromagnetic waves according to requirements, making it a research hotspot in 6G hardware technology.

[0003] Existing WiFi signal enhancement solutions based on passive RIS mainly solve the problem of non-line-of-sight electromagnetic signal propagation by reflecting the signal from a single WiFi router through multiple RIS, thus achieving whole-house WiFi signal coverage. However, they do not have a precise signal enhancement effect, nor do they enhance the signal within the same room.

[0004] In 2022, Li Xingkang, Li Zheng, and Meng Qingmin of Nanjing University of Posts and Telecommunications invented a signal enhancement and distribution scheme based on passive RIS to address the problem of difficult whole-house WiFi 6 signal coverage (see technical solution). Figure 1 and Figure 2 This solution requires large-scale RIS deployment indoors, which is costly. Furthermore, since it uses a passive RIS, the resulting improvement in indoor communication gain is not significant; it only addresses the WiFi coverage issue. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide an indoor WiFi signal tracking and enhancement system and method based on active RIS, which can realize signal tracking and enhancement in the same room, and at the same time, can realize active amplification and enhancement of WiFi signals in other rooms.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] An indoor WiFi signal tracking and enhancement system based on active RIS includes a controllable directional antenna array and a router. The router is placed in the middle of the controllable directional antenna array, and the controllable directional antenna array beamforms the electromagnetic waves emitted by the router.

[0008] Furthermore, the router antenna is a monopole antenna or multiple monopole antennas.

[0009] Furthermore, a direction-aware unit is loaded onto the active RIS to locate mobile terminal devices in the room. The sensing unit on the active RIS shares the same aperture as the RIS reflection unit and uses general direction-finding technology for positioning, providing directional information for the RIS beamforming and realizing the integration of sensing and communication in the RIS.

[0010] Furthermore, the RIS sensing unit adopts a sparsely distributed phased array system, sharing the same aperture with the RIS amplification and reflection unit, which also adopts a sparse array, to form an overall RIS array.

[0011] Furthermore, the RIS sensing unit is provided in three or more units.

[0012] This invention also provides a method for indoor WiFi signal tracking and enhancement based on active RIS, comprising the following steps:

[0013] (1) The mobile terminal sends a signal;

[0014] (2) The sensing unit on the RIS in each room receives the signal and performs positioning;

[0015] (3) To determine and classify the communication status;

[0016] (4) Amplify the signal and accurately track the communication equipment in the room, perform secondary beamforming of the WiFi signal, and realize indoor WiFi signal tracking enhancement.

[0017] Furthermore, the communication situation is judged and classified into two situations: a. Communication that passes through the room where the router is located; b. Communication within the room where the router is located.

[0018] Furthermore, for communication passing through the room where the router is located, the following steps are taken: the router uses a directional array to perform beamforming and sends a direct signal to the RIS in the room where the mobile terminal is located; the RIS reflects and amplifies the signal passing through the wall; the RIS beamforms the reflected signal and sends it to the mobile terminal.

[0019] Furthermore, for communication within the room where the router is located, the following applies: the router uses a directional array for beamforming to send a direct signal to the RIS within the room; the reflected signal from the RIS is superimposed on the signal sent directly from the router to the terminal within the room, thereby improving communication quality through multipath effect.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] (1) The WiFi signal tracking enhancement technology based on active RIS proposed in this invention can achieve signal tracking enhancement in the same room, and at the same time, it can also achieve active amplification and enhancement of WiFi signal in other rooms.

[0022] (2) Existing RIS technology has not been improved at the WiFi router end, while the present invention uses an antenna array for beamforming at the WiFi router end, which can improve the directivity of the router antenna and improve the energy utilization of the system.

[0023] (3) The RIS in this invention contains a sensing unit that can locate mobile communication devices in a room and provide beamforming for the router's antenna and the RIS's beamforming target. Existing sensing schemes based on passive RIS require real-time estimation of incoming waves to obtain the best channel improvement effect due to the time-varying channel. However, in this invention, since the locations of the WiFi router and the RIS are relatively fixed, and the WiFi router directly sends signals to the RIS in wall-penetrating communication, the direction of incoming waves is fixed, which greatly reduces the complexity of the positioning algorithm.

[0024] (4) Existing RIS technology uses passive RIS, which can only improve the channel environment to a very limited extent. However, the active RIS of this invention can reflect and amplify the incoming wave signal, providing a certain gain effect on the signal transmitted by the WiFi router, and better ensuring the strength of the communication signal. At the same time, the active RIS does not need to cover an entire wall like passive RIS; the active RIS only requires a smaller reflective surface. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of a scenario model in which existing technology is applied to this invention.

[0026] Figure 2 This is a flowchart of existing technology methods.

[0027] Figure 3 This is a schematic diagram of the technical solution in Embodiment 1, which places the WiFi router in the middle of a controllable directional antenna array.

[0028] Figure 4This is a schematic diagram showing the shared aperture of the sensing unit and the RIS reflection unit on the active RIS in Embodiment 2.

[0029] Figure 5 The schematic diagram of the RIS array is shown in Example 2, where the RIS sensing unit adopts a sparsely distributed phased array system and shares the same aperture with the RIS amplification and reflection unit, which adopts a sparse array, to form an overall RIS array.

[0030] Figure 6 This is a schematic diagram of a scenario model applied to the present invention in Example 3.

[0031] Figure 7 This is a flowchart of the RIS-assisted indoor communication process of the present invention. Detailed Implementation

[0032] Example 1

[0033] A directional antenna array can beamform electromagnetic waves emitted by router antennas, thereby improving directional gain and reducing unnecessary energy waste in space.

[0034] Commonly used WiFi router antennas on the market primarily use monopole antennas or multiple monopole antennas, radiating electromagnetic waves omnidirectionally. Within the same room, due to the omnidirectional radiation of the WiFi router antenna, most of the electromagnetic energy is directed towards areas where communication is not needed, resulting in unnecessary energy waste. This embodiment proposes a controllable directional antenna array that allows the WiFi router to be placed in the center, enabling beamforming of the electromagnetic waves emitted by the router (e.g., ...). Figure 3 (as shown), thereby achieving better directional emission gain and improving the space utilization of energy.

[0035] Example 2

[0036] This embodiment loads a direction-sensing unit onto an active RIS (Radio Reflector System), enabling the location of mobile terminal devices within a room. The sensing unit and the RIS reflector unit share the same aperture (e.g., ...). Figure 4 As shown in the figure, common direction finding techniques (such as interferometer direction finding and spatial spectrum estimation direction finding) are used for positioning, thereby providing directional information for beamforming of the RIS and realizing the integration of RIS's sensing and communication.

[0037] In this embodiment, the RIS sensing unit adopts a sparsely distributed phased array system, sharing the same aperture with the RIS amplification and reflection unit, which also adopts a sparse array, to form an overall RIS array. Figure 5 As shown, a small number (three or more) of black squares represent RIS sensing units, which occupy a small portion of the entire array. The remaining white squares represent RIS units for amplification and reflection, used for beamforming.

[0038] Example 3

[0039] like Figure 6 As shown, an indoor WiFi signal tracking enhancement system based on active RIS includes the following steps:

[0040] (1) The mobile terminal sends a signal;

[0041] (2) The sensing unit on the RIS in each room receives the signal and performs positioning;

[0042] (3) To determine and classify the communication status;

[0043] (4) Amplify the signal and accurately track the communication equipment in the room, perform secondary beamforming of the WiFi signal, and realize indoor WiFi signal tracking enhancement.

[0044] In step (3), the communication situation is judged and classified into two situations: a. communication through the room where the router is located; b. communication within the room where the router is located.

[0045] For communication passing through the room where the router is located, the following scenarios are included: the router uses a directional array to perform beamforming and sends a direct signal to the RIS in the room where the mobile terminal is located; the RIS reflects and amplifies the signal passing through the wall; the RIS beamforms the reflected signal and sends it to the mobile terminal.

[0046] For communication within the room where the router is located, the following scenarios are considered: the router uses a directional array for beamforming to send a direct signal to the RIS (Radio Router) within the room; the reflected signal from the RIS is superimposed on the signal sent directly from the router to the terminal within the room, thereby improving communication quality through multipath effect.

[0047] The following is a more detailed explanation:

[0048] A small active RIS (Radio Router Identifier) ​​is placed in the corner of each room to amplify signals that penetrate walls and accurately track communication devices within the room, performing secondary beamforming of the WiFi signal. This technology will be discussed in two scenarios: a) communication through the room where the router is located; b) communication within the room where the router is located.

[0049] a. Communication across the room where the router is located:

[0050] First, the sensing unit on the RIS will analyze the electromagnetic waves emitted by mobile communication devices in the room. Figure 7(1) refers to the electromagnetic waves emitted by the mobile communication device. The coordinates of the communication device are obtained through an interferometer positioning algorithm or a spatial spectrum estimation algorithm. Then, starting from the router, the signal emitted by the router is beamformed using an external directional antenna array and directed towards the RIS in the room where the mobile communication device is located (e.g., Figure 7 (as shown in (2)). Next, the RIS in the room reflects and amplifies the WiFi signal passing through the wall, performs beamforming again, and transmits the signal to the mobile communication device (such as...). Figure 7 (As shown in (3)).

[0051] b. Communication within the room where the router is located:

[0052] First, the sensing unit on the RIS in the room analyzes the electromagnetic waves emitted by the mobile communication devices in the room. Figure 7 (4) refers to the electromagnetic waves emitted by the mobile communication device. The coordinates of the communication device are obtained through an interferometer positioning algorithm or a spatial spectrum estimation algorithm. Then, starting from the router, the signal emitted by the router is beamformed using an external directional antenna array, so that the beam is directed towards the RIS in the room. The RIS then reflects the signal back to the communication device in the room (such as...). Figure 7 As shown in (6). The RIS in this room can use the multipath effect (the superposition of signals (5) and (6)) to modulate the reflected router signal, thereby improving the communication quality in the room.

[0053] The above three embodiments can be summarized into a RIS-assisted indoor communication process, such as... Figure 7 As shown, the active RIS of this invention can reflect and amplify the incoming signal, providing a certain gain effect on the signal transmitted by the WiFi router and better ensuring the strength of the communication signal. At the same time, the active RIS does not need to cover an entire wall like a passive RIS; the active RIS only requires a smaller reflective surface.

[0054] Those skilled in the art will recognize that the embodiments described herein are intended to help the reader understand the principles of the invention, and should be understood that the scope of protection of the invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific modifications and combinations based on the technical teachings disclosed in this invention without departing from the scope of the invention, and these modifications and combinations are still within the scope of protection of this invention.

Claims

1. A method for active RIS-based indoor WiFi signal tracking enhancement, characterized in that, Comprise the following steps: (1) mobile terminal sends a signal; (2) the RIS in each room receives the signal and locates the signal; (3) judge and classify the communication situation; (4) amplify the signal and accurately track the communication equipment in the room, perform secondary beamforming on the WiFi signal, and realize indoor WiFi signal tracking enhancement; The judgment and classification of the communication situation are divided into two cases: a. communication through the room where the router is located; b. communication in the room where the router is located; For the case of communication through the room where the router is located, it includes: the router uses a directive array to perform beamforming and sends a direct signal to the RIS in the room where the mobile terminal is located; the RIS reflects and amplifies the wall signal; the RIS performs beamforming on the reflected signal and sends it to the mobile terminal; For the case of communication in the room where the router is located, it includes: the router uses a directive array to perform beamforming and sends a direct signal to the RIS in the room; the reflected signal of the RIS is superimposed with the signal directly sent by the router to the terminal in the room, and the communication quality is improved through multipath effect; The indoor WiFi signal tracking enhancement system based on active RIS comprises a controllable directive antenna array and a router, the router is placed in the middle of the controllable directive antenna array, and the electromagnetic wave emitted by the router is beamformed by the controllable directive antenna array; A direction-aware unit is loaded on the active RIS to locate the mobile terminal equipment in the room, the direction-aware unit on the active RIS is co-antenna with the RIS reflection unit, and a general direction-finding technology is used for positioning to provide pointing information for the beamforming of the RIS, realizing the integration of the RIS sensing and communication.

2. The active RIS-based indoor WiFi signal tracking enhancement method of claim 1, wherein, The router antenna is a monopole antenna or multiple monopole antennas.

3. The active RIS-based indoor WiFi signal tracking enhancement method of claim 1, wherein, The RIS sensing unit adopts a sparse distribution phased array system, which is co-antenna with the RIS amplification and reflection unit using sparse array distribution, and is combined into an integral RIS array.

4. The active RIS-based indoor WiFi signal tracking enhancement method of claim 3, wherein, The RIS sensing unit is provided with 3 or more than 3.

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