Method for more accurately determining the location of a subscriber device in an LTE network

Abstract

The invention relates to location determination in LTE networks. Base station simulators which have unique PCIs and emit synchronization signals (PSS, SSS) are positioned inside the coverage area of a base station. The base station transmits a measurement command (RRC messages) to subscriber devices. Upon receiving signals from the base station simulators, the subscriber devices register the PCIs of the base station simulators, measure the RSRP / RSRQ / SINR, and transmit these data to the base station. At the same time, the subscriber devices are sent a report containing similar measurements carried out for the base station itself. The combination of the obtained data makes it possible to localize the subscriber devices according to the PCIs of the base station simulators and to determine the direction / distance according to the signal level. The invention provides for an increase in the accuracy and reliability of localizing subscriber devices.

Description

[0001] A METHOD FOR INCREASING THE ACCURACY OF DETERMINING THE LOCATION OF A SUBSCRIBER UNIT IN AN LTE NETWORK

[0002] DESCRIPTION

[0003] The invention relates to LTE wireless communication networks, and in particular to methods for determining the location of users in an LTE network with the ability to ensure information security [H04W 4 / 00, H04W 4 / 02, H04W 12 / 00, H04W 12 / 02, H04W 12 / 60, H04W 12 / 63, H04W 12 / 64, H04W 48 / 00, H04W 48 / 08, H04W 48 / 16, H04W 64 / 00].

[0004] In today's environment of centralized enterprise (organization) management, the use of high-tech equipment, and the digitalization of production and management processes, monitoring the level of information security at a facility is becoming more important than ever.

[0005] In the present invention, a facility refers to buildings, structures, utility networks, and adjacent territory separated (isolated) from the outside. The main distinguishing feature of such facilities is the presence of an access control system, meaning that access is permitted to specific individuals. Access is achieved through organizational and technical measures (security, access systems, fencing, video surveillance, etc.), and external interference with the facility's radio network is only possible from outside the facility's perimeter. A facility's radio network (wireless network) refers to a "private" (closed) radio network deployed at the facility to enhance information and physical security.

[0006] A private network (Private LTE - pLTE) is based on the same technology as, for example, public LTE networks, but is not connected to the public infrastructure. All its elements are located within a closed circuit. The main advantages of a private network are high reliability and security while maintaining high data transfer rates and low latency. A private network is a controlled and stable digital data transmission environment, resistant to interference, well-protected, and providing high-quality communication. It is in demand by an increasing number of companies and organizations. Its applications continue to expand. It is worth noting that even a closed (private) network does not provide complete internal control over personnel operations.

[0007] A method for positioning a subscriber equipment UE is known from the prior art [US2024012129A1, published: 11.01.2024] in a wireless network using the observed time difference of arrival (OTDOA), including receiving a first positioning reference signal (PRS) from a reference base station, transmitting a second PRS to the UE in response to receiving the first PRS, wherein the total delay in transmitting the second PRS includes a propagation delay and a processing delay, wherein the propagation delay includes a first amount of time for propagating the first PRS from the reference base station to the base station, and the processing delay includes a second amount of time between receiving the first PRS and transmitting the second PRS; and transmitting to the network entity at least a portion of the total delay for determining the reference signal time difference (RSTD) between the reception by the UE of the third PRS transmitted by the reference base station and the reception by the UE of the second PRS.

[0008] The disadvantage of the prototype is the low accuracy of determining the location of the subscriber device by the base station, which depends on the number of base stations participating in the measurements.

[0009] Also known is a METHOD AND DEVICE FOR DETERMINING THE GEOGRAPHICAL LOCATION OF A CELLULAR COMMUNICATION DEVICE [RU 2410849 C2, published: 27.01.2011], which includes determining the effective areas of the first and second cells of a cellular network based on the relationship between the geographic locations and orientations of the first antenna of the first cell of the cellular network and the second cell of the cellular network, and determining the control transition area on which the cellular communication device is likely to be located at the moment when control over it passes from the first to the second cell, according to which the control transition area is determined based on the effective areas of the first and second cells.

[0010] The disadvantage of the prototype is the impossibility of accurately determining the location of the subscriber device while it is in the service area of ​​one base station, the impossibility of determining the location of the subscriber device when it is in shielded rooms.

[0011] The objective of the invention is to address the shortcomings of the prior art. The technical result of the invention is to improve the accuracy of subscriber device location determination in the LTE network, enhance the reliability of the system, thereby improving location accuracy, and reduce the cost of its development and operation.

[0012] The specified technical result is achieved due to the fact that the method for increasing the accuracy of determining the location of a subscriber device in an LTE network, characterized in that in the service area of ​​the base station of the wireless mobile network of LTE, a fixed placement of at least one base station simulator with a unique physical cell indicator PCI, configured with the possibility of transmitting primary synchronization signals PSS and secondary synchronization signals SSS, in the base station for the subscriber device, measurement parameters are set associated with the procedure for switching the subscriber device between cells without interruption in service and which must be performed by the subscriber device when connecting to the base station and the base station simulator, an RRC Connection Reconfiguration or RRC Measurement Control Request message is transmitted from the base station to the subscriber device,containing instructions for the measurements carried out by the subscriber device and their parameters, ensure the transmission of primary PSS and secondary SSS synchronization signals from the base station simulator, ensure the reception by the subscriber device located in the radiation sector of the base station simulator of the primary PSS and secondary SSS synchronization signals, recording by the subscriber device of the physical identifier of the cell PCI of the simulator and measuring the average value of the power level of the received pilot signals RSRP, and / or the average value of the quality level of the received pilot signals RSRQ and / or the ratio of the level of the useful signal to the noise level SINR and the transmission of the measured data to the base station in the form of a report, simultaneously ensure the transmission from the subscriber device to the base station of a report with the values ​​of RSRP, and / or RSRQ, and / or SINR for the base station itself,After the base station receives reports from the subscriber device, the base station simulator localizes the subscriber device's location using the unique physical cell indicator PCI, and determines the subscriber device's distance from the simulator and the direction from the simulator to the subscriber device using the RSRP, RSRQ, and SINR values. Specifically, the base station simulator is implemented using a software-defined radio (SDR) system.

[0013] In particular, the radiation power of the base station simulator can be set individually for each facility depending on the number of base stations at the facility, the required service area of ​​one base station and one simulator, the terrain, and the radio signal penetration.

[0014] In particular, the base station simulator is installed both indoors and outdoors.

[0015] In particular, the location of the subscriber device based on the RSRP, RSRQ, and SINR values ​​is determined using the amplitude direction finding method.

[0016] In particular, machine learning or a neural network is used to determine the location of a subscriber device, the algorithms of which are executed in a base station or an analytical module connected to the base station.

[0017] Implementation of the invention.

[0018] The essence of the technical solution is to ensure the precise determination of the location of users with LTE subscriber devices using a base station of a wireless LTE mobile network and at least one simulator of a base station of a wireless LTE mobile network for the purpose of monitoring the location of these subscriber devices.

[0019] To achieve this, at least one base station simulator is permanently installed within the base station's service area. It is assigned a unique PCI (Physical Cell Identifier) ​​and has specific coordinates (fixed placement). To improve location accuracy, two or more base station simulators are installed, ensuring radio coverage between at least two simulators, meaning that at least two simulators simultaneously receive a signal from a subscriber device at any point. The more simulators installed within the facility, the more accurately the locations of LTE subscriber devices can be determined.The density of placement of base station simulators also depends on the terrain (in open areas the number of simulators may be less than, for example, in urban areas) and on the radio signal penetration (in areas of the facility with poor radio signal penetration (underground structures, basements) additional placement is required.

[0020] The base station simulator is equipped with transceiver antennas and can be implemented using a software-defined radio (SDR) system with the ability to transmit primary synchronization signals (PSS) and secondary synchronization signals (SSS). The simulator's physical cell identifier (PCI) is determined by the PSS and SSS identifiers as PCI = 3 * SSS + PSS and ranges from 0 to 503, allowing for 504 unique base station simulator identifiers in the network.

[0021] The primary synchronization signal (PSS) is necessary for synchronizing the simulator with the subscriber device using TTI, slots, and OFDM symbols, as well as for calculating the physical cell identifier (PCI) by the subscriber device. The SSS signal enables frame synchronization between the simulator and the subscriber device [http: / / anisimoff.org / lte / lte_synch.html].

[0022] Configuration of the base station simulator parameters can be performed remotely using various wired and wireless protocols (Wi-Fi, LoRa, Ethernet), as well as using Mesh networks.

[0023] The radiation power of the base station simulator, as well as the type and characteristics of the simulator's transmitting and receiving antennas, are selected individually for each facility depending on the number of base stations at the facility, the required service area of ​​one base station and one simulator, the terrain, the radio signal penetration, and the required accuracy of determining the location of each subscriber. The simulator can be designed with the ability to regulate the radiation power of the radio signal.

[0024] Transmitting and receiving antennas used with a base station simulator can be of various types, including directional, omnidirectional, and with all kinds of polarizations.

[0025] The base station simulator can be installed both indoors and outdoors.

[0026] The justification for implementing the invention at the facility is the circumstances associated with monitoring the movement of working personnel within a restricted facility within the service area of ​​at least one base station simulator or a radio coverage zone of two or more base station simulators, as well as taking into account the time the subscriber device is located at a particular facility (its section), where it is impossible to take other organizational and technical measures aimed at ensuring access control.

[0027] In the base station, for the subscriber equipment UE (User Equipment), measurement parameters are set that are related to the procedure of switching the subscriber equipment between cells without interruption in service (handover) and that must be performed by the subscriber equipment when connecting to the base station and the base station simulator.

[0028] The base station transmits RRC Connection Reconfiguration or RRC Measurement Control Request messages to the subscriber device, containing instructions for the measurements to be performed and their parameters. The purpose of this procedure is to configure the subscriber device to perform measurements, generate, and transmit measurement reports to the base station.

[0029] The reports on the measurements carried out by the subscriber equipment must, among other things, include data on the physical identifier of the cell PCI of the simulator, the quality level of the pilot signals RSRQ received from the base station simulator by the subscriber equipment, and / or the level of the average power of the pilot signals RSRP received by the subscriber equipment UE, and / or the value of the ratio of the level of the useful signal to the noise level SINR.

[0030] It is known from the prior art that the LTE standard can define a total of 5 conditions under which reporting is possible, and these are called events. The most suitable events for activating intra-system handover (although others can be used) are those in which the signal from the neighboring base station exceeds the signal from the serving base station by a specified value, or in which the signal from the serving base station becomes worse than the first specified value, while the signal from the neighboring base station becomes better than the second specified value. As soon as the subscriber device detects that the conditions for one of the specified events are met, it sends a measurement report. In this message, the subscriber device reports the RSRP and RSRQ values ​​for the serving and neighboring sectors, as well as the physical identifier of the neighboring sector PCI [http: / / anisimoff.org / lte / handovers / intra-lte_handover.html].

[0031] The subscriber device, being in the radiation sector of the base station simulator, receives from the base station simulator the primary PSS and secondary SSS synchronization signals, records the physical identifier of the cell PCI, which is unique for this simulator, the average value of the power level of the received pilot signals RSRP, and / or the average value of the quality level of the received pilot signals RSRQ and / or the ratio of the level of the useful signal to the noise level SINR and transmits the measured data to the base station in the form of a report (measurement reports).

[0032] At the same time, the subscriber device informs the base station of the RSRP and / or RSRQ and / or SINR values ​​for the base station itself.

[0033] After the base station receives reports from the subscriber device, the location of the subscriber device is localized using the unique physical indicator of the PCI cell of the simulator, and the distance of the subscriber device from the simulator is determined using the amplitude direction finding method and the direction from the simulator to the subscriber device using the values ​​of the RSRP and / or RSRQ and / or SINR indicators measured by the subscriber device.

[0034] Machine learning or a neural network can be used to determine the location of a subscriber device, the algorithms of which are executed in an analytical module. This analytical module is capable of performing calculations to determine the location of a subscriber device based on the PCI, RSRP, RSRQ, and SINR parameters received from the subscriber device.

[0035] The described method can be implemented at a site with multiple base stations, with the base stations connected to a common analytics module. Furthermore, each base station can use multiple sector antennas, each with its own Cell ID.

[0036] The analytical module can be implemented using an electronic computing device, such as a PC, laptop, etc., and can be mounted either internally or externally. Calculations can also be performed within the base station itself. The technical result—improving the accuracy of subscriber device location determination in the LTE network, increasing the system's reliability, and reducing the cost of its development and operation—is achieved by using at least one base station simulator within the base station's service area. This allows for an increased number of measurements performed by the subscriber device when it is within the service area of ​​both the base station itself and the base station simulator, thereby significantly improving localization accuracy and reducing measurement error.

[0037] Given that a base station simulator is a simple technical solution, a large number of such devices can be deployed at a site, unlike actual base stations, which, unlike simulators, require constant maintenance, configuration, etc.

[0038] Essentially, a simulator is a low-cost emitting device that can be implemented using any software-defined receiver, such as the USRP B210. The simulator's function consists of emitting a small data packet without receiving or analyzing information from the subscriber device, other base stations, the network core, etc., while the actual base station must constantly maintain communications (exchange packets over the air) with the subscriber devices, as well as with the network core (EPC).

[0039] Thus, the design of the base station is an order of magnitude more complex, which leads to higher energy consumption, reduced reliability, and also increases the labor intensity of repair and maintenance, which, among other things, requires increased competence from service engineers, unlike a simulator, which does not require changes to settings during operation.

[0040] Considering that the base station simulator has a relatively limited functionality (it does not require feedback from subscriber devices) so that their operation does not “interfere” with the base station, their operating frequencies may differ from the operating frequencies of the base station, but taking into account the frequencies supported by the subscriber device.

[0041] In 2024, the inventor deployed an LTE network at a dedicated site. A single USRP B210 base station simulator was installed within the coverage area of ​​the network's base station, 100 meters from the base station. Experimental studies of this network showed that subscriber device localization accuracy when simultaneously within the coverage area of ​​the base station and the base station simulator averaged 25 meters. Two base station simulators were then installed, 100 meters apart from each other and from the base station, with overlapping radio coverage areas of these two simulators. In this case, subscriber device localization accuracy when simultaneously within the coverage area of ​​the base station and the two base station simulators averaged 5 meters. During the experiment, the possibility of installing base station simulators with different radiating powers within the coverage area of ​​a single base station was considered.We found that, in the case of a subscriber device's limited radiating power entering the simulator's coverage area, it is possible to reliably determine the maximum distance limited by the simulator's radiating power. This allows for the creation of various algorithms for determining the subscriber device's location, including setting the simulator's power to ensure radiation coverage within a limited area of ​​the facility requiring special attention to information privacy. The presence of the subscriber device within the simulator's coverage area will be unambiguously interpreted as the subscriber device's presence within that area. In this case, if there are areas with different localization requirements, different power settings can be set for the simulators.

[0042] For example, the accuracy of determining the location of a subscriber device by a base station in an LTE network depends on the methods used. Thus, according to the CI+TA method, the accuracy is approximately 200-300 meters [https: / / mobile-review.com / standard / gps-in-nets.shtml]. When using TOA technology, the accuracy of location depends on the signal bandwidth, the accuracy of synchronization and the signal propagation environment. Calculated data show the possibility of determining the location of cellular network subscribers with an accuracy of up to 125 meters without modifying radiotelephones [http: / / www.bnti. ru / showart.asp?aid=514&lvl=05]. In real conditions, depending on the density of base stations, the accuracy of location determination can reach 50-100 meters within city limits and up to 1 km outside it. In most cases, this accuracy can only be achieved if the subscriber device regularly uses communication services [https: / / tr-page.yandex.ru / translate?lang=en-ru&url=https%3A%2F%2Fen.wikipedia. org%2Fwiki%2FMobile_phone_tracking].

[0043] The invention can be used to ensure information security in the field of wireless mobile communication systems, in particular the GSM, UMTS, LTE, NR standards, by monitoring the location of subscriber devices that pose a potential threat to information and / or physical security within a restricted area with special regulatory requirements for maintaining data confidentiality.

[0044] The invention can be used to control access of persons carrying mobile communication subscriber devices to restricted access objects (territories).

[0045] The invention can be used to detect the activity of subscriber devices at locations where base station simulators are installed.

Claims

FORMULA 1. A method for increasing the accuracy of determining the location of a subscriber device in an LTE network, characterized in that in the service area of ​​a base station of a wireless mobile network of LTE, a fixed placement of at least one base station simulator is provided, made with a unique physical cell indicator PCI with the ability to transmit primary synchronization signals PSS and secondary synchronization signals SSS without receiving and analyzing information from the subscriber device, other base stations or the network core, in the base station for the subscriber device, measurement parameters are set associated with the procedure for switching the subscriber device between cells without interruption in service and which must be performed by the subscriber device when connecting to the base station, an RRC Connection Reconfiguration or RRC Measurement Control Request message is transmitted from the base station to the subscriber device,containing instructions for the measurements carried out by the subscriber device and their parameters, ensure the reception by the subscriber device located in the radiation sector of the base station simulator of the primary PSS and secondary SSS synchronization signals, the recording by the subscriber device of the physical identifier of the cell PCI of the simulator and the measurement of the average value of the power level of the received pilot signals RSRP, and / or the average value of the quality level of the received pilot signals RSRQ and / or the ratio of the level of the useful signal to the noise level SINR and the transmission of the measured data to the serving base station in the form of a report, simultaneously ensure the transmission from the subscriber device to the served base station of the value of RSRP, and / or RSRQ, and / or SINR for the base station itself, after the base station receives reports from the subscriber device according to the unique physical indicator of the cell PCI of the base station simulator, the location of the subscriber device is localized, and according to the values ​​of RSRP, and / or RSRQ,and / or SINR measured by the subscriber device for the base station and the base station simulator determine the distance of the subscriber device and the direction to the subscriber device from the simulator and the base station.

2. The method according to paragraph 1, characterized in that the base station simulator is implemented on the basis of a software-defined radio system SDR.

3. The method according to paragraph 1, characterized in that the radiation power of the base station simulator can be set individually for each object depending on the number of base stations at the object, the required service area of ​​one base station and one simulator, the terrain, and the passability of the radio signal.

4. The method according to paragraph 1, characterized in that the base station simulator is installed both indoors and outdoors.

5. The method according to paragraph 1, characterized in that the location of the subscriber device based on the RSRP, RSRQ, SINR values ​​is determined using the amplitude direction finding method.

6. The method according to paragraph 1, characterized in that machine learning or a neural network is used to determine the location of the subscriber device, the algorithms of which are executed in the base station or an analytical module connected to the base station.