FR3043298A1 - - Google Patents

Abstract

The present invention makes it possible to reconfigure, in a preventive manner, using a network of spectrum controllers connected together, the channels used for the transmission and / or the reception of one or more radio base stations of a user. secondary, to avoid interference with primary users.

Description

Description of the state of the art

To maximize spectrum usage, new access methods have been defined that allow primary users to share spectrum with secondary users. For example, the "Federal Communications Commission" has defined how to share the 3.5 GHz band between primary and secondary users (in "FCC 15-47"). A subset of this band is reserved primarily for use under license, while the remaining part is reserved exclusively for unlicensed use.

When a primary user is detected in a given geographical area, the secondary users must stop using the spectrum on the frequencies used by the primary users. One possible way to detect primary user emissions is to deploy a network of RF sensors.

Figure 1 shows an architecture for detecting a primary user in accordance with the state of the art. A multiplicity of RF sensors, called RFS, is deployed in a given geographical area. A spectrum controller (for example a SAS server in the case of the US 3.5 GHz band) is notified when these RF sensors detect the RF signals of a primary user. The spectrum controller then reconfigures the network of secondary users (for example, turns off radio base stations or requests radio base stations to reduce their transmission power), to avoid interference with primary users.

In current spectrum sharing solutions based on the detection of primary user RF signals, the reconfiguration of the radio frequencies used by the secondary user radio base stations is performed upon the detection of a user's RF signals. primary.

In these solutions, for reasons of confidentiality, it is not possible to store the information collected by the RF sensors relating to the use of radio frequencies by the primary users.

Consequently, the reconfiguration of the radio frequencies used by the radio base stations can only be performed reactively, which introduces the following disadvantages: this reactive approach introduces a delay between the primary user detection and the complete reconfiguration of the radio base stations, during which mutual interference may impact primary and secondary users. - this reactive approach can lead to a bad user experience, for users connected to secondary user radio base stations, since there is no time to move these users gradually to other frequencies for transmission or reception.

The present invention overcomes these limitations by exploiting channel reconfiguration information broadcast by other radio base stations to remotely initiate reconfiguration while protecting the privacy of primary users.

DESCRIPTION OF THE FIGURES

Figure 1 shows an example of architecture according to the state of the art.

Figure 2 shows an example of architecture on which the present invention is applicable.

Figure 3 describes the steps to determine when to reconfigure a radio base station according to the present invention.

Figure 4 shows an example of a Reconfiguration Report.

Figure 5 shows an example of Reconfiguration Rules.

Figure 6 shows an example of preventive reconfiguration according to the present invention. DESCRIPTION OF THE INVENTION Architecture of the solution

Figure 2 illustrates an example of architecture on which the present invention is applicable.

This figure shows a deployment of radio base stations, named ST, belonging to the same or to different operators. Each radio base station is capable of communicating via a radio interface, for example with the devices belonging to users, named DI to D4.

RF sensors, called RFS, capable of listening to radio frequencies, and detecting radio signals can be deployed near ST radio base stations, or embedded on ST radio base stations, or integrated with radio stations. ST radio base. Each RF sensor is connected to a spectrum controller SM. Instead of or in addition to RF sensors, called RFS, the measurements obtained by the third party network (eg ESC - "Environmental Sensing Capability" in the case of the US 3.5 GHz band) may be provided to spectrum controllers.

The manner of notifying a spectrum controller of the detection of a primary user is outside the scope of the present invention.

The spectrum controller supplies the radio base stations ST with the allowed frequencies for transmission and reception. The spectrum controllers are connected to each other and able to exchange information, for example through an IP network. The information exchanged between spectrum controllers is used to determine which frequencies to allocate to each ST radio base station.

Figure 2 shows an example of an architecture in which spectrum controllers are distributed. In this case, each spectrum controller is responsible for allocating the frequencies to a single radio base station ST. The spectrum controller may be physically embedded or integrated with the ST radio base station.

Communication between spectrum controllers and RF sensors can be done via a direct physical link, or wirelessly (for example, using Wi-Fi or LTE). Some spectrum controllers can be connected to multiple RF sensors. Conversely, some spectrum controllers may not be connected to any RF sensor

The spectrum controllers may communicate with the radio base stations via an entity controlling the ST radio base station network. In the case of a 3GPP network, this entity can be the "Network Manager". This case is illustrated in Figure 1 by SMI which communicates with STI via the interfaces [C2] and [C3]. In another alternative, the spectrum controllers can communicate directly with the radio base stations, for example through an IP network. This case is illustrated in Figure 2 by SM2 and SM3 which communicate with ST2 and ST3 via the interface [C1]. Other radio base stations not controlled by a spectrum controller, or whose spectrum controllers are not connected to the spectrum controllers of STI ST3 stations, named FST in the figure, may be deployed in the same geographical area. The devices communicating with these radio base stations, named FD1 to FD4 are also shown in this figure. Details of the steps of the method for reconfiguring a radio base station in a preventive manner

Figure 3 illustrates the steps taken to reconfigure a radio base station preventively in accordance with the present invention.

The following 5 operations are performed at each radio site: A. Reconfiguration Report Broadcast B. Receiving Reconfiguration Reports C. Reconfiguration Report Analysis D. Radio Base Station Preventive Reconfiguration E. Updating Reconfiguration Rules

The following sections describe these steps in more detail. A. Reconfiguration Report Broadcast Whenever a radio base station reconfiguration associated with a spectrum controller is performed by a spectrum controller, a Reconfiguration Report is created by this spectrum controller, except in the case of a spectrum controller. a preventive reconfiguration performed in accordance with the present invention.

This reconfiguration may be the result of the detection of a primary user near the radio base station associated with the spectrum controllers. In another alternative, this reconfiguration may be the result of a request from the radio base station for more bandwidth for transmission or reception, or the result of a decrease in the bandwidth requirements of this base station. radio.

A reconfiguration report may contain, for example: i. The list of channels deallocated by the spectrum controller to that radio base station, ii. The list of channels newly allocated by the spectrum controller to this radio base station, iii. A timestamp indicating when the reconfiguration report was created. iv. The location of the radio base station reconfigured by the spectrum controller (eg latitude, longitude and height).

Figure 4 shows an example of a Reconfiguration Report. In this example, following the detection of a primary user near the radio base station, the channels 1,3 and 4 are deallocated and the channels 6 and 7 are allocated to the radio base station.

When the spectrum controllers associated with the radio base stations of different operators are connected to the same network of spectrum controllers, some information provided by the Reconfiguration Reports can be encrypted (for example using the public key of the certificate of an operator) in order to be accessible (for example using the private key of an operator's certificate) only to the spectrum controllers associated with the radio base stations of the same operator.

Once created, the Reconfiguration Report is broadcast on the spectrum controller network and stored locally. B. Receiving Reconfiguration Reports

Each spectrum controller receives all Reconfiguration Reports broadcast on the network that connects them to each other. C. Analysis of Reconfiguration Reports

This step is initiated each time a Reconfiguration Report is received.

During this step, the spectrum controller uses the information included in the Reconfiguration Reports, as well as the operational parameters, stored in the spectrum controller, currently defined for the radio base station (for example the currently allocated channels), so that determine whether the radio base station should be reconfigured preemptively according to the Reconfiguration Rules stored in the spectrum controller.

The Reconfiguration Rules provide a set of criteria that must be met to initiate a preventive reconfiguration.

Minimum Reconfiguration Reports Received

When a large number of Reconfiguration Reports indicate that a given channel has been deallocated, there is a high probability that this channel has been preempted by a primary user. This primary user can be mobile, and therefore, potentially move near the radio base station connected to the spectrum controller that receives these Reconfiguration Reports.

The "Minimum Reconfiguration Reports Received" parameter indicates the minimum number of Reconfiguration Reports to be received, indicating that a given channel has been deallocated to initiate a preventative reconfiguration.

The preventive reconfiguration may consist of asking the radio base station not to use a given channel and allocating a new channel to the radio base station, if such a channel is available.

In another alternative, the spectrum controller can simply send a notification to the radio base station indicating that a given channel is likely to be deallocated in the near future. The radio base station can use this information, for example, to give a lower priority to this channel at the time of the bandwidth allocation. This minimizes the quality of service degradation in the case where a primary user using this channel moves near the radio base station. A validity period may also be provided by the spectrum controller in the notification, or preconfigured in the radio base station, indicating the time period during which the radio base station must take into account the received notification.

The further a primary user is located away from a given radio base station, the lower the probability that this primary user will move near this radio base station. Thus, the "Minimum Reconfiguration Reports Received" parameter may vary depending on the distance. In another alternative, in order to take into account the impact of the environment in estimating the propagation range of the RF signals of a primary user, the "Minimum of Reconfiguration Reports Received" may vary depending on the 'propagation loss.

Maximum Distance

A maximum distance between two radio base stations can be configured, beyond which two Reconfiguration Reports received from spectrum controllers associated with these radio base stations are considered unrelated to the same potential primary user. Instead of a maximum distance, a maximum propagation loss can be defined, making it possible to take into account the impact of the environment in estimating the range of propagation of the RF signals of a primary user.

Density of deployment of radio base stations

The "Minimum Reconfiguration Reports Received" parameter may vary depending on the density of the deployment of the radio base stations. When a small number of radio base stations are deployed on a given area, the number of Reconfiguration Reports, indicating that a given channel was deallocated to be received before initiating a preventive reconfiguration, is smaller than when a large number of radio base stations are deployed on a given area. Validity period

A parameter defining the validity period of the Configuration Reports, beyond which the Reconfiguration Reports are no longer used by the spectrum controller to determine whether a preventive reconfiguration of the radio base station associated with that spectrum controller is to be performed, can be configured in the Reconfiguration Rules.

Sample Reconfiguration Rules

Figure 5 shows an example of Reconfiguration Rules.

The "Minimum Reconfiguration Report Received" indicates the minimum number of Reconfiguration Reports to be received on a given channel to initiate a reconfiguration. This parameter depends on the distance and density of the radio base stations.

In this example, the first column indicates that if the network deployment density is 10 radio base stations per square kilometer, at least 15 Reconfiguration Reports must be received from spectrum controllers associated with radio base stations located less than 10 kilometers, before initiating a reconfiguration.

Similarly, the 5® "column indicates that if the network deployment density is 20 radio base stations per square kilometer, at least 35 Reconfiguration Reports must be received from spectrum controllers associated with radio stations. radio base within 50 kilometers, before initiating a reconfiguration.

The parameter "Maximum Distance Between Reconfiguration Reports" indicates that the distance between each base station whose reconfiguration has been notified must be less than 30 kilometers.

The "Validity Period" parameter indicates that the Reconfiguration Reports must be received in a 10-second time window. D. Preventative Reconfiguration of Radio Base Station

When it determines in step C that some channels need to be deallocated preemptively, the spectrum controller checks whether other channels are available. The spectrum controller then sends a request to the radio base station indicating the deallocated channels and the newly allocated channels.

In another alternative, the spectrum controller can simply send a notification to the radio base station containing the list of channels allocated to the radio base station that are likely to be deallocated.

Figure 6 shows an example of reconfiguration of radio base stations in accordance with the present invention.

In this example, SMI, SM2, and SM3 send a Reconfiguration Report indicating that channel 1 is deallocated, and SMI, SM3, and SM8 send a Reconfiguration Report indicating that channel 2 is deallocated. SM4 receives and analyzes these reports using its Reconfiguration Rules. According to these rules, at least 3 Reconfiguration Reports must be received, from the spectrum controllers associated with radio base stations located less than 3 kilometers apart, to perform a preventive reconfiguration. SMI, SM2 and SM3 are located within 3 kilometers of each other. The Reconfiguration Rules criteria are fulfilled for channel 1, and SM2 initiates a preventive reconfiguration for this channel. In contrast, the radio base station associated with SM8 is located more than 3 kilometers from other radio base stations associated with spectrum controllers reporting that a reconfiguration has been performed on channel 2. Thus, although 3 Reconfiguration reports have been received for channel 2, SM4 does not perform preventive reconfiguration for this channel. E. Update reconfiguration rules

The spectrum controllers can store the history of the preventive reconfigurations performed in accordance with the present invention. Using this information, spectrum controllers can check whether a preventive reconfiguration has been relevant or not, by checking whether or not they have received a notification from the RF sensors or from an entity controlling the network. RF sensors, indicating the presence of a primary user on the channel on which a preventive reconfiguration has been performed, within a given time interval. This time interval may be an estimate of the maximum time required for a primary user, whose presence is expected to be in the vicinity of the location provided in the received Reconfiguration Reports, to reach the radio base station.

If, according to this analysis, the rate of relevant reconfigurations is low, the spectrum controller can modify the parameters of the Reconfiguration Rules in order to limit the number of preventive reconfigurations. For example, the "Minimum Reconfiguration Reports Received" parameter can be increased. Conversely, if according to this analysis, the spectrum controller is frequently notified of the presence of a primary user near the radio base station with which it is associated, without having anticipated preventive reconfiguration, the spectrum controller can modify the Reconfiguration Rules settings to increase the number of preventative reconfigurations. For example, the "Minimum Reconfiguration Reports Received" setting may be decreased.

Claims (6)

1) A method for preconfiguring, by a spectrum controller connected to a network of spectrum controllers, the channels used for transmission and / or reception by a radio base station of a secondary user, composed of following operations: i. Creation and dissemination of a reconfiguration report by said spectrum controller, during the reconfiguration of the radio base station connected to this spectrum controller, except in the case where this reconfiguration is a preventive reconfiguration according to the present invention. ii. Receiving, by said spectrum controller, reconfiguration reports from the other spectrum controllers connected to the spectrum controller network. iii. Analysis, by said spectrum controller, reconfiguration reports received in step ii, to determine whether the radio base stations connected to said spectrum controller must be reconfigured preemptively, according to the reconfiguration rules stored by said controller of spectrum. iv. When identifying that the radio base station connected to said spectrum controller is to be reconfigured preemptively, sending a request by said spectrum controller to said radio base station to indicate the deallocated channels and the newly allocated channels. 2) The method according to claim 1, characterized in that said reconfiguration report contains at least one of the following elements: i. The list of channels deallocated by the spectrum controller of the radio base station connected to that spectrum controller, ii. The list of channels allocated by the spectrum controller to the radio base station connected to that spectrum controller, iii. A timestamp indicating when said reconfiguration report was created, iv. The location of the radio base station reconfigured by this spectrum controller. 3) The method according to at least one of claims 1 to 2 characterized in that said reconfiguration rules used to determine whether said spectrum controller must remotely reconfigure said radio base station contain all or a subset of the elements following: i. a threshold parameter, indicating the minimum number of reconfiguration reports to be received indicating that a given channel has been deallocated, and may vary depending on: a. the maximum distance or maximum propagation loss between two radio base stations, and, b. the deployment density of radio base stations. ii. a parameter defining the period of validity of the received reconfiguration reports, beyond which the reconfiguration reports are no longer used by the spectrum controller to determine whether said radio base station is to be reconfigured preventively. iii. a parameter indicating the maximum distance between radio base stations, beyond which two reconfiguration reports received from the spectrum controllers associated with these radio base stations are considered not to be associated with the same potential primary user. 4) The method according to at least one of claims 1 to 3, characterized in that said preventive reconfiguration is to deallocate channels, allocate channels, or send a notification indicating the channels likely to be deallocated in the near future, said notification may optionally include a validity period indicating the time during which the radio base station receiving said notification shall take into account said notification. 5) The method according to at least one of claims 1 to 4, characterized in that said reconfiguration rules can be modified by a spectrum controller, from the rate of preventive reconfigurations performed and identified as relevant. 6) The method according to at least one of claims 1 to 5, characterized in that some of the information provided in the reconfiguration reports can be encrypted, so that this information is accessible only to controllers of spectrum associated with radio base stations of the same operator.