FR3039961A1 - METHOD OF CALIBRATING A DYNAMIC ACCESS MANAGEMENT SYSTEM AND RADIO SPECTRUM SHARING - Google Patents

Abstract

The method described in the present invention gives secondary users, from actual measurements of the interference levels produced by the operation of their own radio communication systems, the possibility of calibrating the radio wave propagation models. These models of radio wave propagation are used by the preemption system which manages the dynamic and shared access to the radio spectrum or more generally to any radio base station reconfiguration system of a radiocommunication network. The radio spectrum is here shared between one or more primary holders and one or more secondary users.

Description

Description of the state of the art

Traditionally, access and use of the radio spectrum is permitted in two ways: either with a "licensed" license, or with a license-exempt license called "unlicensed".

A "licensed" license means that the rights of use are exclusively granted, on a national basis, in time, in space and for a defined frequency band. An example of licensed use is the 2 GHz frequency band for the provision of third generation mobile communications services.

An "unlicensed" license means that devices that meet certain technical conditions (transmit power, frequency band) can share the radio spectrum, be used anywhere and at any time, without guarantee of quality of service. An example of use is the 2.4 GHz frequency band for the provision of Wi-Fi and Bluetooth access services.

There is a third approach that aims to allow a limited number of secondary users to use a band of frequencies already allocated to one or more primary holders. This approach was adopted, for example, to define the modalities of use of the 2300-2400 MHz frequency band in Europe (as specified by the European Telecommunications Standards Institute - documents ETSI TS 103 154 and ETSI TS 103 235). , or to define the terms of use of the 3550-3700 MHz frequency band in the United States (as specified by the Federal Communications Commission - FCC document 15-47). Access to these shared frequency bands must be in accordance with the sharing rules included in the user licenses granted to secondary users; these include the technical conditions to ensure the absence of harmful radio interference to the primary holder operating in a defined frequency band.

This access regime allows the primary holder to have priority access to radio resources in the frequency band shared with secondary users. In particular, the primary holder may be entitled at any time to require exclusive access and preempt the shared frequency band, over a given geographical area and duration.

Figure 1 illustrates a preemption system that manages the dynamic and shared access to the radio spectrum in accordance with the state of the art, in which a primary holder [PRI] can at any time obtain exclusive access and preempt a frequency band by modifying the content of a central server [SC] via the [IHM1] interface,

The controllers [C] of the secondary users are notified of the spectrum access request via the interface [C1] and calculate, using radio wave propagation models, the reconfiguration parameters of the radio base stations. [S] to be modified in order to satisfy this request. These controllers then forward network reconfiguration requests via the [C2] interface to the network management infrastructure [NM].

Current limitations

The current mechanism does not allow secondary users [SEC], based on actual measurements of the interference levels produced by the operation of their own radio systems, to be able to calibrate the radio wave are used by the system that manages shared access to the radio spectrum.

These limitations force the secondary user [SEC] to reduce his coverage area to avoid interference due to inaccuracies in radio wave propagation patterns. This results in non-optimal use of the spectrum by secondary users [SEC].

List of Figures :

Figure 1: general view of a radio frequency preemption system according to the state of the art.

Figure 2: general view of a radio frequency preemption system according to the present invention. Alternative 1: Use of Radio Frequency Sensors (RF Sensors) near the primary holder's radio sites.

Figure 3 is a general view of a radio frequency preemption system according to the present invention. Alternative 2: Use of Radio Frequency Sensors (RF Sensors) positioned outside the primary holder's radio sites.

Process description

Figures 2 and 3 illustrate the additions of the present invention with respect to the state of the art described in Figure 1. The method described in the present invention is broken down as follows: i. The secondary user [SEC], via the [C] controller [ADM C] administration tool, requests the start of the system calibration procedure that manages shared access to the radio spectrum. ii. The controller [C] relays this request to start the calibration procedure to the central server [S_C]. iii. Upon receipt of the request to start the calibration procedure, the central server [S_C] instructs the RF sensors [S_RF] to start the measurements of the surrounding radio field. iv. The RF sensors [S_RF] send, continuously or at a defined periodicity, the measurements to the central server [S C]; each measurement is time stamped, georeferenced by each RF sensor [S_RF] before being sent. v. Radio-frequency field measurements received by the central server [S_C] are filtered by the central server to send to the controller [C] only the measurements which are free of interference produced by the operation of the primary holders' radiocommunication systems [ PRI]. vi. On receipt of the time-stamped and georeferenced measurements, the controller [C] compares these measurements with the electromagnetic fields calculated using radio wave propagation models. vii. The secondary user [SEC], via the [ADM_C] administration tool of the controller [C], or the controller [C] based on a predefined margin of error, terminates the calibration procedure when it considers that the results calculated by the controller [C], from the propagation models, are sufficiently close to the real measurements. viii. Once the calibration is complete, the controller [C] uses the propagation models thus calibrated in the radio spectrum preemption process and in particular for the calculation of the radio base station reconfiguration parameters [S] as described by the state art.

Before starting the calibration procedure

Each controller [C] registers the topology of the radio network of its secondary user [SEC] by collecting, via the interface [C2], the deployment information of the radio base stations [S] and the antennas [A] which are associated.

These are the equivalent radiated isotropic powers expressed in dBm, the central transmission frequencies expressed in MHz, the transmission channel widths expressed in MHz, and for each antenna the geographical position, the height above ground, the polarization, azimuth, sector, inclination, vertical and horizontal radiation patterns and information if the antenna is inside or outside a building.

Each controller [C] combines the network topology of its secondary user [SEC], and other environmental information such as the georeferenced density of the population, the digital terrain model, the height of the building, the occupation of the Soils, the administrative units of the territory and it creates with the help of radio wave propagation models and dedicated algorithms a dynamic and real-time cartography of the radio environment.

This is dynamic and real-time mapping as it changes as the input information changes described above change; this dynamic and real-time mapping contains 5 dimensions which are latitude, longitude, altitude, frequency and time.

Each controller [C] calculates in real time at each point of the geographical zone which is assigned to it and for the frequency band to be shared, the level of theoretical cumulative electromagnetic fields emitted by all the antennas [A] of the radio stations. base [S] of the secondary user network [SEC].

Local dynamic mapping of the radio environment can be visualized on a computer screen using a Geographic Information System.

Starting the calibration procedure The secondary user [SEC], via the administration tool [ADM_C] of the controller [C], requests the start of the calibration procedure of the system that manages the access to the shared radio spectrum.

This calibration procedure can be initiated, for example, for the following reasons: at the start of a controller; following the deployment of new radio base stations for the secondary user; following a modification by a primary holder of its use of the spectrum; - Periodically or occasionally to update propagation models in geographical areas where the propagation of radio waves is likely to be affected by environmental changes (eg following new construction in an urban area , or following a major forest fire).

In order to limit the impact of the calibration procedure on the correct functioning of the system, the date and time to initiate this procedure can be selected, for example: - by favoring slots where the primary holder does not preempt ( for example in the case of a periodic preemption). - by sending a calibration request to the primary holder, in order to give the primary holder the opportunity to choose the most appropriate time to perform this procedure.

The controller [C] relays, via the interface [C3], the request to start the calibration procedure to the central server [S C].

To enable the central server [S_C] to determine the sensors to activate the request to start the calibration procedure includes the geographical area to be calibrated and optionally assistance information for detection, by RF sensors [S_RF], interferences related to the operations of the secondary user network [SEC], for example, the radio technology used (LTE, UMTS ...) and its mode of transmission (FDD, TDD, ...), the central frequency of the transmission channel, the width of the transmission channel, or the list of cell codes (PCI or "Physical Cell ID") that can be received. This information can be used by RF sensors [S_RF] to discriminate interference from secondary user network operations [SEC] from interference in primary user network operations [PRI].

The central server [SC] sends, via the interface [SI], the request to the RF sensors [S_RF] to start the electromagnetic field measurements, continuously or at a defined periodicity, on the frequency band or bands that are operated. by the secondary user [SEC] at the origin of the calibration request.

The central server [S C] associates and sends with each request a unique identifier to allow the central server [S_C] to simultaneously manage several calibration requests from different controllers.

The central server [S_C] includes in the request, if available, the assistance information for the detection of interference related to the operations of the network of the secondary user [SEC].

Collection of radio field measurements

Each RF sensor [S_RF] locally measures its surrounding electromagnetic field on the requested frequency band (s), with or without the assistance information for detecting interference from secondary user network (SEC) operations, and sends , via the interface [SI], continuously or at a defined periodicity, the measurements at the central server [SC]. Each measurement is time stamped, georeferenced by each RF sensor [S_RF] before being sent.

For each measurement received, using the associated information (measured field, frequency, date, time and geographical position of the measurement), the central server [S_C] checks, from its knowledge of the use of the spectrum by the primary holder (s) [PRI] if the measurement was, in principle, interfered with the operations of the primary-holder [PRI] radiocommunication systems. This knowledge of the use of the radio spectrum by the primary holder (s) [PRI] is part of the state of the art of the system that manages access to the shared radio spectrum.

The central server [S_C] filters the measurements to send, via the interface [C3], to the controller [C] at the origin of the calibration request, only the measurements which are free of interference produced by the operation of the primary holders [PRI] radiocommunication systems.

Calibration of propagation models

On receipt of the time-stamped and georeferenced measurements, the controller [C] compares these measurements with the electromagnetic fields calculated using radio wave propagation models. This comparison can be the subject of an iterative process for which the parameters of the propagation models used are adjusted until the calculations approach the actual measurements.

End of the calibration procedure and return to the state of the art The secondary user [SEC] via the administration tool [ADM C] of the controller [C], or the controller [C] according to a predefined margin of error, terminates the calibration procedure when it considers that the results calculated by the controller [C], from the propagation models, are sufficiently close to the real measurements. Once the calibration is complete, the controller [C] uses the propagation models thus calibrated in the radio spectrum preemption process and in particular for the calculation of the radio base station reconfiguration parameters [S] as described by the state art.

Alternative 1 vs. Alternative 2

FIG. 2 represents the alternative 1 of the invention where the RF sensors [S_RF] are positioned near the radio sites of the primary user [PRI]. This alternative allows, a priori, a better opportunity of calibration because the method will access actual measurements made close to the positions that will be taken into account by the system that manages access to the shared radio spectrum.

However, it is not always possible either to install RF [S RF] sensors near the radio sites of the primary user [PRI], or simply because the radio sites of the primary user [PRÏ] do not are not at fixed positions, or known in advance. In this case, alternative 2, represented by FIG. 3 of the invention, also makes it possible to calibrate the system. The RF [RF] sensors are then positioned at remarkable locations that will be used to calibrate the propagation models for situations similar to the sharing situations expected with the primary user [PRI].

Claims (9)

Claims 1) A method of calibrating a radio frequency spectrum and shared access management system composed of the following steps: i. The secondary user [SEC], via the [C] controller [ADM C] administration tool, requests the start of the system calibration procedure that manages shared access to the radio spectrum. ii. The controller [C] relays this request to start the calibration procedure to the central server [S_C]. iii. Upon receipt of the request to start the calibration procedure, the central server [S_C] instructs the RF sensors [S_RF] to start the measurements of the surrounding radio field. iv. The RF sensors [S_RF] send, continuously or at a defined periodicity, the measurements to the central server [S_C]; each measurement is time stamped, georeferenced by each RF sensor [S_RF] before being sent. v. The radio-frequency field measurements received by the central server [SC] are filtered by the latter to send to the controller [C] only the measurements which are free of interference produced by the operation of the primary holders' radiocommunication systems [ PRI]. vi. On receipt of the time-stamped and georeferenced measurements, the controller [C] compares these measurements with the electromagnetic fields calculated using radio wave propagation models. vii. The secondary user [SEC] via the [ADC_C] administration tool of the [C] controller, or the [C] controller based on a predefined margin of error, terminates the calibration procedure when he considers that the results calculated by the controller [C], from the propagation models, are sufficiently close to the actual measurements. viii. Once the calibration is complete, the controller [C] uses the propagation models thus calibrated in the radio spectrum preemption process and in particular for the calculation of the radio base station reconfiguration parameters [S] as described by the state art. 2) The method according to claim 1, characterized in that its initiation by the secondary user [SEC] is triggered for one of the following reasons: - when starting a controller; following the deployment of new radio base stations for the secondary user; - following a modification by a primary holder of its use of the spectrum; - Periodically or occasionally to update propagation models in geographical areas where the propagation of radio waves is likely to be affected by environmental changes (eg following new construction in an urban area , or following a major forest fire). 3) The method according to at least one of the preceding claims, characterized in that it is programmed by favoring slots where the primary holder [PRI] does not preempt (for example • in the case of pre-emption periodic) or by sending a calibration request to the primary holder to give the primary holder the opportunity to choose the most appropriate time to perform this procedure. 4) The method according to at least one of the preceding claims, characterized in that the central server [SC] associates and sends with each request to start the electromagnetic field measurements to the RP [S_RF] sensors a unique identifier to allow the server central [SC] to simultaneously manage several calibration requests from different controllers. 5) The method according to at least one of the preceding claims, characterized in that the request to start the calibration procedure includes the geographical area to be calibrated to allow the central server [S_C] to determine the sensors to activate. 6) The method according to at least one of the preceding claims, characterized in that the request for starting the calibration procedure includes assistance information for the detection, by the RF sensors [S_RF], of the related interferences. to the operations of the secondary user network [SEC], for example, the radio technology used (LTE, UMTS ...) and its transmission mode (FDD, TDD, ...), the central frequency of the transmission, the width of the transmission channel, or the list of cell codes (PCI or "Physical Cell ID") likely to be received. This information is used by RF sensors [S_RF] to discriminate interference from secondary user network operations [SEC] from interference from primary user network operations [PRI]. 7) The method according to at least one of the preceding claims, characterized in that the RF sensors [S_RF] locally measure its surrounding electromagnetic field on the requested frequency band or bands, with or without the assistance information for the detection interference from secondary user network operations [SEC], and sending continuously or at a defined periodicity, the measurements to the central server [SC]. Each measurement is time stamped and georeferenced by each RF sensor [S_RF] before being sent. 8) The method according to at least one of the preceding claims, characterized in that for each measurement received, using the associated information (measured field, frequency, date, time and geographical position of the measurement), the central server [S_C] verifies, on the basis of its knowledge of the use of the radio spectrum by the primary holder (s) [PRI] whether the measurement has undergone, a priori, interference related to the operations of the primary holders' radiocommunication systems [ PRI]. This allows the central server [S_C] to filter the measurements to send to the controller [C] at the origin of the calibration request, only the measurements which are free of interference produced by the operation of the radiocommunication systems of the primary holders [PRI]. 9) i The method according to at least one of the preceding claims, characterized in that the comparison, by the controller [C], of real measurements with the electromagnetic fields calculated using radio wave propagation models makes the subject of an iterative process for which the parameters of the propagation models used are adjusted until the calculations approach the actual measurements. The method according to at least one of the preceding claims, characterized in that there is provided two alternative for the deployment of the RF sensors [SRF]: a first alternative of the invention or the RF sensors [S RF ] are positioned near the radio sites of the primary user [PRI]. This alternative allows, a priori, a better opportunity of calibration because the method will access actual measurements made close to the positions that will be taken into account by the system that manages access to the shared radio spectrum. - However, it is not always possible either to install RF [S RF] sensors near the radio sites of the primary user [PRI], or simply because the radio sites of the primary user [PRI] are not at fixed positions, or known in advance. In this case, a second alternative of the invention also allows the calibration of the system. The RF [RF] sensors are then positioned at remarkable locations that will be used to calibrate the propagation models for situations similar to the sharing situations expected with the primary user [PRI].