Real-time authentication and monitoring system for smart building access control: LiFi-based social distancing system

Abstract

A building access control system and method that may incorporate multiple authentication processes including the biometric verification the user, verification of user ID and the measurement of vital health signs. The invention uses a system access point 01 and a hand-sized portable device 06 which wirelessly communicate via LiFi. RFID communications 07 may be used as a fallback communication method if LiFi is unavailable. The portable device may comprise a receiver, transmitter, display, fingerprint sensor, temperature sensor, and an oximeter for measuring heart rate and blood oxygen levels. Access decisions can be based upon: an initial mutual authentication process between the portable device and the access point, user identity, user health status, and user clearance permissions. The user identity is confirmed via the fingerprint sensor of the portable device. User health status is assessed from body temperature, heart rate and blood oxygen levels. The portable device transmits user data wirelessly using LiFi or RFID, ensuring high-security, contactless operation to minimize physical interaction with external surfaces. By integrating these technologies, the invention aims to enhance social distancing, reduce infection transmission risks, and improve building access control.

Description

This section shows the background related and explains the main problems this invention solves and introduces the essential and important features. The recent global pandemic caused by the coronavirus (COVID-19) has introduced significant challenges for countries worldwide, resulting in high death rates and a heavy burden on both public and private sectors. This situation has led to an increased awareness of the importance of precautionary measures and safety protocols to mitigate the spread of infectious diseases. COVID-19 primarily spreads through direct contact with contaminated physical objects, such as tools, everyday materials, doors, and building entrances. Infected individuals may be asymptomatic, which complicates early detection of the virus. Consequently, when a positive case is identified, all individuals who have been in contact with the infected person must undergo medical testing to determine their infection status. Given the impracticality of daily testing for large populations and the fact that many individuals do not strictly follow health guidelines, it becomes essential to develop systems that can monitor or measure vital medical signs indicative of infection. Such systems would offer an effective method of identifying individuals who may be at risk without the need for immediate medical intervention. Body temperature and blood oxygen levels are critical health indicators that can signal potential COVID-19 infection. However, building access points, where individuals typically use keys, fingerprints, or access cards for entry, may present a significant risk of virus transmission due to frequent contact with shared surfaces. To reduce the risk of infection, it is essential to develop and implement access control systems that identify individuals with low risk to wirelessly request access to buildings, thereby minimizing direct physical contact with surfaces and reducing the likelihood of contamination. Additionally, to effectively manage access to facilities, track potential exposure, and ensure that only those who are healthy and have not come into contact with infected persons are permitted entry, it is crucial to maintain accurate records of individuals entering and exiting the premises. Existing access control systems are often vulnerable to unauthorized use, as they rely on shared devices, equipment, or traditional methods such as phone apps, QR codes, wearable sensors, or position-tracking systems without sufficient authentication processes. For instance, in traditional access card systems, lost or shared cards could potentially be used by unauthorized individuals to gain access. Similarly, systems that rely on shared devices or traditional methods for authentication may fail to ensure proper access control, particularly in the absence of real-time monitoring, and especially during a pandemic. Thus, it is important to develop systems that incorporate realtime authentication to verify access during the login process, ensuring that only authorized individuals are granted entry while continuously monitoring for potential health risks. Furthermore, when implementing building access control systems in such environments, it is critical to consider potential component failures and design alternative routes to maintain functionality. Although several social distancing systems for contact tracing and monitoring have been developed, most of these systems rely on distinct approaches and various wireless technologies. However, no current patent integrates both building access control and social distancing measures in a unified solution, highlighting the novelty of the present invention. SUMMARY OF THE INVENTION The invention is basically a system that provides a social distancing method for building access control with an authentication process. It relies on multiple factors for checking user health status and exchanging information between the user and system wirelessly without physical interaction with external entities. This process allows the examination of user health status safely without worrying about the possibility of transmitting infection / disease to others, especially during a pandemic. The system performs a real-time authentication process through the use of a series of processes, including on-site access request check, fingerprint check, and user vital health signs check through the use of a hand-sized portable device and an access point (AP), wherein the user data, including the ID, is collected and combined with the user vital health signs, including body temperature, oxygen level in the blood, and heart rate for the building access request process. The system comprises a hand-sized portable device held by the user and an AP that is installed at the gate of the building that is connected to the main system. The system uses an on-site authentication process using the portable user device to ensure authorized use of the device and prevent others from using the device. The portable device and the system double-check the fingerprint to provide a higher level of authentication. All the collected data will be used for user authentication, health symptom checks for potential infection risk, and contact tracing for accurate monitoring. All the data will be sent wirelessly from the portable user device to the system AP without physical contact from the user to any shared / external equipment, wherein light fidelity (LiFi) and RFID systems are used as the medium of data transmission in this system that can help preserve a higher privacy level of the user data, wherein the coverage area of the transmission is confined within the room and the direct line of sight from the transmitter to the receiver. LiFi uses visible light (VL), making it ideal for electromagnetic-free zones, such as operating rooms or MRI areas, while also minimizing interference and ensuring patient safety. LiFi offers enhanced security since its signals are confined to physical spaces, reducing the risk of eavesdropping. Its use of the VL spectrum also provides higher bandwidth availability compared to the congested RF spectrum, allowing for faster and more reliable communication in environments with many connected devices. The portable device can be manufactured using off-the-shelf components, and it is easy to build. Using LiFi technology in the portable device makes it super-fast for data transmission, sending modulated data. This modulation enables LiFi to obtain higher data speeds and effectively use the neglected VL spectrum, providing more bandwidth relative to the saturated RF spectrum. The short transmission distance between transmitters and receivers using LiFi technology in this system makes it secure within a range of approximately two meters, specifically at the gate of the building, because it uses VL for data transmission, which requires a direct line of sight between the transmitter and the receiver. It mitigates the possibility of data leakage and unauthorized access. It is clear from this that the data is restricted to a particular location, which makes it more difficult for unauthorized users to intercept the signal. Therefore, this feature makes the user data more private and mitigates the possibility of data leakage and unauthorized access, wherein the data is unable to be detected by unauthorized entities in the nearby area. In the event of a failure of the LiFi sensors, the access request's RFID method provides an alternative for data transmission. The emergency entrance will activate if both the LiFi system and the RFID sensors fail. The proposed system prevents data manipulation since it relies on real-time authentication and data collection and processing. Only authorized individuals can use the portable device. The system's base state can find and keep track of all decisions without any help from a person. This way, the administrator only needs to keep an eye on the system in case of an emergency and doesn't have to make decisions about access by hand. The combined capability of using light for lighting and communication improves energy economy, making LiFi an optimal choice for portable devices by delivering enhanced speed, dependability, and performance. The product design is innovative, offering multiple benefits and performing various tasks within a single user device and system AP. Its primary goal is real-time employee monitoring across multiple levels, incorporating contact tracing principles and user authentication to enhance the social distancing experience and building access process. There are several factors included in the proposed product. The system consists of two parts: the device, which is also called “the user-device side”, and the system, which is also called “the system-AP side”, which represents the gate, and the system might have multiple APs. The following points succinctly summarize the benefits: - The size of the device is convenient and lightweight. - The device is rechargeable and has a replaceable battery. - The system uses multiple authentication processes that can provide a high level of authentication. - The device features a monitor to provide users with easy-to-use instructions. - Built-in and irreplaceable memory unit (storage) that prevents data manipulation, - The vital health sensors in the portable device replace the traditional measurement shared devices. - The device is energy efficient as it uses LiFi, which consumes less power than other wireless technologies. - The system considers two methods for the access request and one solution for emergency access. - The FP sensor provides authentication for two entities, including the device and the system, which replaces the built-in FP sensor scan for authentication that is normally placed near the gate (entrance). - The wireless approach replaces the direct / traditional ID / card scan method, which reduces the infection rates and transmitted diseases and viruses. The proposed system is designed for facilities and industries that have employees who have to check in and out of the building, mainly private and government sectors. The system's flexibility to accommodate businesses of varying sizes and organizational structures makes it very appealing to a wide variety of businesses. Unlike other social distancing systems, the proposed system does not allow the user to opt out or deceive the system. The user in the proposed system has to go through the prescribed process in order to be able to gain access to the building. BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described solely by way of example and with reference to the accompanying drawings in which: Fig.1: Shows the system diagram and components. Fig .2: Shows the proposed user device architecture and components. Fig.3: Shows the internal components of the user device. Fig.4: Shows the side view and upper view of the user device. Fig.5: Shows a flow diagram illustrating the pre-processing of the access request and access type signalling. Fig.6: Shows a flow diagram illustrating the authentication and access request process on the user side. Fig.7: Shows a flow diagram illustrating the authentication and access request process on the system side. DETAILED DESCRIPTION OF THE INVENTION The proposed product consists of two sides, the system side (building) and the device side (user). Each side has its own components. The following description explains the functionalities and steps of the system that are shown in the drawings. The system-AP side: An overview of the system components is shown in Fig. 1, wherein the gate is equipped with an optical wireless communication-based building entrance with LiFi AP as transmitter (01) and LiFi signal detectors as receiver (02). The LiFi transmitter (01) is used for illumination and data transmission. A building might have multiple entrances. Optional: each entrance is equipped with (01) and (02), both of which are connected to the Central Control Unit (CCU), which contains the system server (03), local storage (04), and monitoring computer (05). The components (03), (04), and (05) are updated whenever data is sent or received, wherein decisions are made and data is stored and processed. The component (03) is in charge of processing the data and making decisions, while (04) stores and exchanges the data with (03) and (04). Optionally, a cloud-based storage can be added to support the component (04) as a backup for the data. Optionally, the monitoring computer (05) shows information about system status, user information, user logs, etc. A web-based application can be added to monitor the system remotely, wherein options and decisions can be made without the need for the administrator to be at the site. The LiFi APs and receivers ((01) and (02)) at each entrance are connected to the gate and the CCU, which controls the gate and the access-related decisions. The component (01) is the system AP transmitter (STx), which is responsible for sending optical signals from the system side to the user side (06). Optionally, a small screen can be attached near the gate and the LiFi receiver (02) or the RFID sensor (07), wherein instructions and status can be shown to the user. Optional, the gate can be a slide door or a normal door with a lock. The system will decide whether to open or lock the door, regardless of its type. A motion sensor can be added as well to detect the user movement, wherein the gate is closed after the user walks in. The component (02) is the system AP receiver (SRx), which is responsible for receiving an uplink optical signal from the user device and forwarding it to the CCU for processing. The component (03) is responsible for processing the date from / to (01) and (02) and making decisions with the help of the component (04), wherein all the data of all users are kept, including logs, IDs, and history of logs. The component (05) is responsible for monitoring all the processes, which can be a desktop with a manual control system and an admin panel. The component (06) is the portable user device that will be explained and discussed in the next sub-section. This device serves as the user's interface for communicating with the system. An RFID sensor (07) is placed near the gate as an alternative transmission medium in case the sensors of LiFi (01)(02) fail to deliver the service. This RFID sensor is responsible for data exchange between the system and the user. The RFID sensor (07) communicates with the user through the user device (06). The user device side: This portable user device is the main component of the proposed invention. Fig.2 shows the architecture and the components of the user portable device (06). Each user should have their own device. Each employee should receive a device from their employer. The item (11) shows the front view, (12) shows the internal view of the device, and (13) and (14) show the side view and the upper view of the device. The user device has external and internal components. The main external components of the user device are shown in Fig.2 (11). The internal components of the user device are shown in Fig.3 (12). A side view (13) and upper view (14) of the device are shown in Fig.4. The combination of the components in the device represents the novelty of this invention and makes it unique. Each portable device has a LiFi transmitter (15), an RFID sensor (16), and a LiFi receiver (17) that are shown in the front view (11) in Fig.2, and the upper view (14) in Fig.4. In the front view (11), the rest of the main components are shown, including a screen (18), fingerprint sensor (19), temperature sensor (20), and a button (21). Optional, the screen (18) can be normal or a touch screen. The component (15) is the user receiver (URx), which is the receiver of the portable device that is responsible for receiving the optical signal coming from (01). Depending on the manufacturing design, this component may consist of a photon-diode (PD) or a solar cell. The component (17) is the user AP transmitter (UTx), which is the transmitter of the portable device that is responsible for transmitting data from the device to the system (02). This component is made of a light-emitting diode (LED) where the LiFi signal is supposed to be modulated based on the Intensity Modulation / Direct Detection (IM / DD) technique. The RFID sensor (16) works as the transmitter (UTx) and the receiver (URx). The monitor (18) displays instructions and choices for the user's convenience. The screen can show messages to the user throughout the process. It is also responsible for showing decisions, battery life, power status, etc. The component (19) is the fingerprint sensor, where the user’s fingerprint is used for authentication purposes for further processing. The component (20) is the temperature sensor, which is responsible for measuring the user's temperature for further processing. The component (21) is the user control pad, which contains a select button. Optional: the pad may contain additional buttons for navigating through options. The pad facilitates user choices and data transmission through the component (17). The internal view (12), which is shown in Fig. 3, is the core component and element inside the device, including a computing unit (22) that is responsible for processing the data and making decisions. The component (23) is the circuit board, which is the main motherboard of the device. The component (24) is the clock, wherein the time is recorded in the device, which is used for recording accurate times for user decisions and related events. The component (25) is the storage that is used for storing all the data of the user pre- and post-transmission on both sides, as well as the log history and the internal settings and configurations of the device that are supposed to be set during the manufacturing process, and it can also be customized based on specific preferences. The component (27) is a portal for charging the battery (26), which is a rechargeable type that enables the device to be used wirelessly and is responsible for powering up all the components in the device. The component (23) is responsible for connecting all the components of the user portable device (11), (12), (13), and (14). The side view (13) and the upper view (14) are shown in Fig. 4. (13) shows the width of the device, and it contains an essential component wherein the ON / OFF key (28) is used for turning the device ON and OFF. Optionally, the component (28) can be placed on the left or the right side of the device. An oximeter (29) is shown in (13), which consists of a heart rate measurement sensor and an oxygen level measurement sensor. The oximeter is for collecting the user’s body temperature value and heart pulse rate as additional vital health signs for making decisions. The user should place his / her finger in the gap of the oximeter (29) while holding the device to allow the device to collect oximeter-related data. The moving part (30) is part of the oximeter (29) that is supposed to provide easy and dynamic use wherein users with different sizes of fingers will be able to place their finger in the gap for user data collection through the oximeter (29). The piece (31) is responsible for attaching (30) to the body of the device (32). The gap (33) between (30) and (32) provides a dynamic functionality when using the oximeter (29) and offers flexibility for the moving piece (30). The working procedure: The working procedure of this proposed system will be shown and discussed in several diagrams. Fig. 5 shows the pre-processing process (100), which refers to the start point of the system, wherein the start point (101) represents the status of the system AP (01) and the user device (06) status. During this process, the user device (06) is actively listening for the initial signal, which is believed to originate from the AP at the building's gate. On the other hand, (01) is broadcasting the access type signal to the potential user. The system administrator can determine whether to use LiFi or RFID for that specific gate based on the access type. The system administrator can manage the access type. Without the access type signal, 06 will not be able to start sending or receiving further data. This means the user must reside in the system AP coverage area first to be able to start the building access request process. The data of the access type that is sent (102) to the user (06) is either from the LiFi system transmitter (01) using the transmitter (STx) when the LiFi AP is used, wherein the signal will be received using the user receiver (15) (URx), while the RFID sensor (07) is used instead to transmit the signal (102) to the user RFID sensor (16). Optionally, the access type can be represented to the user by a monitor with instructions or through the use of the LED, wherein the LED shows which sensor is operating and being used. The system administrator will determine and configure the access type signal. The system checks the chosen system wherein the process of access request using the LiFi system (103) starts when the LiFi system is chosen; if not, then the system checks whether the RFID sensors are chosen (104). The selected method and associated sensors will initiate data transmission. Whenever neither of the two methods is available, (103) nor (104), the emergency access is activated as the alternative method (108) in order to avoid system failure. The related sensors, LiFi or RFID, in the user portable device (06) will be activated based on the received access type signal (103)(104) received by the system AP (102), wherein the user access process using LiFi (105) is activated whenever LiFi (103) is chosen and the user access process using RFID (106) is activated whenever RFID (104) is chosen. Whatever method of transmission is chosen, (103) or (104), the process of the user access request is identified as a unified process for further explanation in the coming steps, marked as the user access request process (107). Fig. 6 illustrates the authentication process between the portable device and the system AP that is considered as part of the user access request process (107). Fig. 6 includes the full process of access request (107) on the user side (200), wherein the process starts when the user steps in the zone under the system transmitter (01) and, after receiving the confirmation from the system (102) and (06), will start in the standby mode (201), and the user will be allowed to use the device. The user sends a request to the system AP (202); the request is to initialize the process of access request where the transmitted data consists of the ID of the device, and this transmitted data is sent from UTx to the SRx. After the request is received by the system, the user keeps checking for incoming confirmation (203); this data is sent from STx to URx. This proposed invention uses four authentication processes to ensure security and authentication, wherein these authentication processes are proposed exclusively in this invention. Specifically, the first authentication (A1-a and A1-b) and the second authentication (A2) are shown in Fig. 6, while the third authentication (A3-a and A3-b) is shown in Fig. 6 and 7, and the fourth one (A4) is shown in Fig. 7. Both processes (202) and (203) in Fig. 6 are considered the first authentication processes on the user device side (A1-a). At this point, the user device (06) is waiting and keeps checking for the received confirmation from the system, wherein the next process starts and is permitted by the device if the statement is true, and the portable device will ask the user to proceed for the data collection process (204); otherwise, the user device will go back to the standby mode (201). The waiting time can be set during the software development. For instance, 90 seconds of maximum waiting time will be enough until going back to (201). The device (06) will ask the user to provide the fingerprint using the fingerprint sensor (19), wherein the fingerprint data of the user will be collected (204) for further processing. The device checks the collected data for verification, wherein the user will be allowed to use the device (205) if the statement is true; otherwise, the user will be denied access to the portable device (06)(206). Each user has a special ID that is stored and encrypted in the portable device, which is set in the configuration phase by the admin of the system. The processes of (204) and (205) are considered the second authentication process (A2) presented in this invention, wherein another layer of authentication is added to the system process, specifically, between the portable device (06) and the user only. After successfully completing the second authentication (A2), other user data are collected, including body temperature (T), heart rate (HR), and oxygen saturation (O2sat), wherein the user device (06) asks the user to proceed and provide the required health data (207). The user sends the access request (209) using the collected data, wherein the data are traveling from the UTx (17) to the SRx (02) or (07) for further processing by the system. The process (209) is the third authentication process (A3-a) of this invention on the user side. The user device (06) stores all data locally (208) in the device (25) after finishing the process of (206) or (209), wherein access might be granted or denied. Fig. 7 shows the data transmission, processing, and authentication process between the portable device and the system’s APs from the system AP side (300) that is also considered as part of the user access request process (107). The standby mode starts with the system (301), where the system is listening and waiting for incoming access requests from users (302) from the UTx (06) to the SRx (02) or (07). While the system is not receiving any requests, it remains in standby mode (301). On the other hand, if the condition is met, then the system stores the received data on the local storage of the system (303) for contact tracing and keeping track of the user. Subsequently, a confirmation will be transmitted (304) from the system transmitter STx (01) or (07) to the user’s receiver URx (15) or (16), thereby allowing the user to proceed with the data gathering process. The processes of (302) and (304) are considered the first authentication processes on the system side (A1-b). The system subsequently enters a standby mode, awaiting the necessary data input from the user (209) to continue processing, wherein the system checks whether the required data is received (305); otherwise, the system waits for a fixed time before going back to the state (302) for checking incoming requests. This waiting time can be customized at the time of development and manufacturing. Upon successful data reception, it will proceed to the next step. The system then checks whether the user is authorized for this process using the received user ID (fingerprint) (306); while the condition is not met (No), the access request is denied (307), which makes the system go back to the standby mode (301), and if the condition is met, it goes to the next process that consists of storing the data and processing the remaining received data for further decisions. Whenever a user is denied access (307), the system goes back to the standby mode (301) for new users, wherein the gate receives the final decision (310). The combination of (305) and (306) is considered the fourth authentication (A4) of this invention, wherein the user ID is checked for access permission to the building in general or in a specific part of the building, wherein some users are given a clearance to places while others are not allowed to request access. The decision in the process of (A4) relies on the user ID for checking the clearance of the user, using the fingerprint data only. Optionally, the system administration has the ability to change the clearance of the user in order to control access to certain gates of the building. In case the user is allowed to request access at the targeted gate, the system stores the received user data for processing wherein the user health data are checked (308), including (T), (HR), and (O2sat). The most vital data that is being checked for making the final decision (309) is where a certain degree threshold of values is used for evaluating the user’s health status. These threshold values are marked as (T_tsh) for the (T), (HR_tsh) for the (HR), and (O2sat_tsh) for the (O2sat). The values can be set at the time of development based on the assessment of the situation and the health risk. The processes of (308) and (309) are considered the third authentication process on the system side (A3-b). This authentication is made for the assessment of the user’s health status. Optionally, the administration can be given the choice ofchanging these values for flexibility of the system. For example, the body temperature caused by a certain disease might be different from another. When the condition of (309) is false, the access is denied (307), and when it is true, the access is granted, and both of these decisions are made (310). Finally, after the decision is made, the final data is stored in the system for proper monitoring (311). As a summary of the overall steps, the user turns on the device, approaches the gate, receives the initial signal to be able to use the device, sends back an access request to the system, the system checks the request's validity, and sends a confirmation to the user. The user provides all the required data using the portable device, starting with the fingerprint, then followed by the health-related data, and sends all data to the system. The system checks and makes a decision based on the received user data, wherein the user might be denied or granted access successfully.

Claims

1. A real-time authentication and monitoring system for building access control, comprising:- a hand-sized portable user device configured to collect user data, including fingerprint biometric data and vital health signs, and- a system access point (AP) installed at a building entrance, configured to communicate wirelessly with the portable user device, wherein the system is configured to:■ provide secure and reliable building access control process,■ combine fingerprint biometric data and vital health signs as criteria for building access decisions,■ use wireless data transmission via Light Fidelity (LiFi) technology to request access to the building, minimizing physical contact, and■ employ a 4-phase authentication process that will provides that necessary data for making decisions which verifies and checks the AP, user identity, user health status, and user’s clearance permissions.

2. The system of claim 1, wherein the portable user device comprises:- a fingerprint sensor for collecting user fingerprint data,- one or more health sensors for measuring vital health signs, including body temperature, heart rate, and blood oxygen saturation,- a LiFi transmitter and receiver for wireless communication with the system AP, and- an RFID sensor as a fallback communication mechanism in case of LiFi failure.

3. The system of claim 1 or 2, wherein the 4-phase authentication process comprises:Phase A1: Mutual Initial Authentication- A1 -a: Verification of the portable user device by the system AP, wherein:■ the system AP transmits an access type signal wirelessly via LiFi or RFID to the portable user device,■ the portable user device verifies the access type signal and activates the corresponding LiFi or RFID communication components, and■ the portable user device transmits a unique device identifier (ID) to the system AP.- A1 -b: Verification of the system AP by the portable user device, wherein:■ the system AP confirms receipt of the device ID and transmits a confirmation signal back to the portable user device, and■ the portable user device validates the confirmation signal to ensure communication integrity with the authorized system AP.Phase A2: Biometric User Authentication- Collection of the user’s fingerprint data via the fingerprint sensor on the portable user device,- On-device encryption and temporary storage of the fingerprint data,- Cross-verification of the fingerprint data against pre-registered biometric templates stored in the portable device’s irreplaceable memory unit, and- Conditional progression to Phase A3 only upon successful fingerprint match, thereby ensuring the portable device is used by its authorized owner.Phase A3: Health Status Verification- A3-a: Collection and encryption of vital health signs by the portable user device, including:■ body temperature measured via the temperature sensor,■ heart rate and blood oxygen saturation (O2sat) measured via the oximeter sensor, and■ wireless transmission of the encrypted health data to the system AP via LiFi or RFID.- A3-b: Server-side evaluation of the health data by the system AP, comprising:■ comparison of the received health data against predefined thresholds for body temperature (T_tsh), heart rate (HR_tsh), and blood oxygen saturation (O2sat_tsh),■ real-time determination of infection risk based on deviations from said thresholds, and■ denial of access if any health parameter exceeds or falls below its corresponding threshold.Phase A4: Final Authorization and Access Decision- Server-side validation of the user’s clearance permissions stored in the system’s local or cloud-based storage,- Integration of the results from Phases A1, A2, and A3 to generate a final access decision, wherein access is granted only if:■ the user’s fingerprint is authenticated,■ the user’s health status meets predefined safety criteria, and■ the user has authorized clearance for the requested building area,- Wireless transmission of the access decision to the portable user device and activation of the building entrance mechanism (e.g., unlocking doors) upon successful authorization.

4. The system of any preceding claim, wherein the system is configured to:- prioritize LiFi for wireless data transmission between the portable user device and the system AP, and- switch to RFID for data transmission if the LiFi system is unavailable, and- activate an emergency access mechanism if both LiFi and RFID systems fail.

5. The system of any preceding claim, wherein the portable user device further comprises:- a built-in, irreplaceable memory unit for secure storage of user data, and - a rechargeable battery for powering the device.

6. The system of any preceding claim, wherein the system AP comprises:- a LiFi transmitter and receiver for wireless communication with the portable user device,- an RFID sensor for fallback communication, and- a central control unit (CCU) for processing user data and making access decisions.

7. The system of any preceding claim, wherein the vital health signs collected by the portable user device include:- body temperature,- heart rate, and- blood oxygen saturation, and wherein the system is configured to compare these values against predefined thresholds to assess infection risk.

8. The system of any preceding claim, wherein the system is configured to:- store user data, including access logs, health data, and authentication records, in a local storage unit, and- optionally synchronize the stored data with a cloud-based storage system for backup and remote monitoring.

9. The system of any preceding claim, wherein the portable user device is configured to:- display instructions and system status to the user via a built-in screen, and- guide the user through the authentication and health data collection process.

10. The system of any preceding claim, wherein the system is configured to:- operate in electromagnetic-sensitive environments by utilizing LiFi technology, which uses visible light for data transmission, and- ensure high data security by confining LiFi signals to a direct line of sight between the portable user device and the system AP.11.A method for real-time authentication and monitoring for building access control, comprising the steps of:- receiving an access type signal from a system AP at a building entrance, wherein the access type signal indicates whether LiFi or RFID is to be used for communication,- collecting user data, including fingerprint biometric data and vital health signs, using a portable user device,- transmitting the collected data wirelessly to the system AP using LiFi technology, or RFID if LiFi is unavailable,- performing a 4-phase authentication process to verify the user’s identity and health status, and- granting or denying access to the building based on the results of the authentication process.

12. The method of claim 11, wherein the 4-phase authentication process comprises:- verifying the portable user device and system AP (Phase A1),- authenticating the user via fingerprint verification (Phase A2),- verifying the user’s health status based on vital health signs (Phase A3), and- authorizing access based on user clearance and health status (Phase A4).

13. The method of claim 11 or 12, further comprising:- activating an emergency access mechanism if both LiFi and RFID systems fail, and- storing user data and access logs for contact tracing and monitoring purposes.

14. A portable user device for real-time authentication and monitoring in building access control systems, comprising:- a fingerprint sensor for collecting user fingerprint data,- one or more health sensors for measuring vital health signs, including body temperature, heart rate, and blood oxygen saturation,- a LiFi transmitter and receiver for wireless communication with a system AP,- an RFID sensor for fallback communication, and- a built-in memory unit for secure storage of user data.

15. The portable user device of claim 14, further comprising:- a rechargeable battery for powering the device, and- a built-in screen for displaying instructions and system status to the user.

16. A system AP for real-time authentication and monitoring in building access control systems, comprising:- a LiFi transmitter and receiver for wireless communication with a portable user device,- an RFID sensor for fallback communication,- a CCU for processing user data and making access decisions, and- a local storage unit for storing user data and access logs.

17. The system AP of claim 16, further comprising:- a monitoring computer for displaying system status and user information, and- a cloud-based storage system for backup and remote monitoring.

18. A computer-readable medium storing instructions that, when executed by a processor, cause the processor to perform the method of any one of claims 11 to

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