WO2010049659A1

WO2010049659A1 - Method and system for locating radio communication terminals in standby mode in a cellular radio communication network

Info

Publication number: WO2010049659A1
Application number: PCT/FR2009/052102
Authority: WO
Inventors: Stéphane Hedarchet
Original assignee: Alcatel Lucent
Priority date: 2008-10-31
Filing date: 2009-10-30
Publication date: 2010-05-06
Also published as: JP2012507235A; EP2351441A1; FR2938148A1

Abstract

A method is dedicated to the locating of radio communication terminals (T1- T4) in standby mode in a cellular radio communication network (RC) subdivided into location zones (ZL1-ZL2) associated with zone identifiers and comprising at least one cell (C11-C23). This method comprises, when a radio communication terminal (T1) in standby mode enters a zone of radio coverage of a local radio access point (FB 112), implanted in a cell (C11) of a location zone (ZL1) having a zone of radio coverage of greater area than its own, and associated with a zone identifier different from that of the location zone (ZL1) of which its cell (C11) forms part, i) a step of recovering the zone identifier of this local radio access point (FB112), ii) a step of connecting this terminal (T1) to this local radio access point (FB 112), and iii) a step of initiating, by this terminal (TU) a procedure for updating the location zone at the network (RC) with the zone identifier recovered, so that the network associates the recovered zone identifier with the terminal (T1).

Description

METHOD AND SYSTEM FOR LOCATING RADIO COMMUNICATION TERMINALS IN SLEEP MODE IN A CELLULAR RADIO COMMUNICATION NETWORK

The invention relates to the location of radio communication terminals in cellular radio communication networks, and more precisely the location within such networks of radio communication terminals in a fashion veilie (oυ "idle ^• >>)

Some applications, such as its applications for emergency calls or information delivery or real-time advertising based on location (or geographical position), need to know quite accurately and as often as possible the location (geographical position) where users of (radio communication) terminals are located. This location information can be obtained in different ways.

Thus, they can be obtained by satellite positioning devices (for example of the GPS type) which are located in the terminals of the users. Unfortunately, few terminals are equipped with such devices _, especially because of their cost. Also, these devices do not work well, if at all, when they are located ^inside buildings. In _addition, the acquisition ^of location information by these devices can be relatively slow (especially due to the length of what the skilled person called in English the "Time to First Ftx").

They can also be obtained by the access points of a WiFi type network whose coverage area is superimposed on the area of the cellular network in which a terminal is located. Unfortunately, there is still no localization solution that can be implemented with all the different WiFi technologies. In addition, the number of terminals with dual communication mode (cellular and WiFi) is very limited, especially because of the cost .

They can also be obtained by the communication network radio) cellular. Indeed, since a cellular network is decomposed into cefluies associated with cell identifiers and covering known geographical areas, it is therefore possible to estimate the position of a terminal from the identifier of the cell to which it is connected. (provided that ^it is not in standby mode). The accuracy of its focus of the terminal (in connected mode) depends on the size of the cell to which it is connected. This accuracy can be significantly increased by implementing triangulation techniques.

If the termina! is in sleep mode, accuracy is usually much lower. Indeed, it depends then on the size of the localization area in which the terminal in standby mode is located, which depends on the number of cells that constitute it and the dimensions of these cells. It is recalled that in a 3G network every time a termina! is powered up it retrieves the zone identifier of the location area, to which belongs the ceSiufe in which it is located, in the messages that are broadcast by this cell on its beacon channel (called BCCH), then communicates to the network this zone identifier for the network to store its terminator identifier (for example the IMS!) in correspondence with said zone identifier (registration procedure).

So that ^a registered terminal remains within one of the cells of a location area does not have to report his movements to the network. However as soon as a registered terminal leaves a locafisafon area to enter a new focusing zone, it must initiate a procedure for making the location area update from the network so that it replaces by ^the area identifier this new zone of location the zone identifier of the old focusing zone which was previously stored in correspondence of its terminal identifier,

When a terminal is in standby mode, the only location information that can be obtained about it from the network is the geographical position which corresponds to the zone identifier of the location area which is stored by the network in correspondence of its identifier of terminai. It will be understood that the accuracy of this location information can be (very) insufficient for some applications.

The ^invention therefore aims to ^improve the situation.

It proposes for this purpose a method, dedicated to the location of radio communication terminals in idle mode (or idle) in a cellular radio communication network subdivided into location zones associated with zone identifiers and comprising at least one cell, and comprising, when ^a terminai of in veilie mode radio communication enters a radio coverage area ^of an ^access point radio local area, located in a cell ^of a location area having an upper surface radio coverage area to his own, and associated with a zone identifier different from that of the localization zone, have been included in his list,

- a stage of recovery of ^the area identifier of the access point radio room,

a step of connecting this terminal to this local radio access point _, and

- a step ^for ^initiating, by the terminal, a procedure for making the location area update from the network with the retrieved area identifier such that the network associates this to terminai recovered Zone ID (which corresponds at the known geographical position of the local radio access point to which i> just connected).

The method according to ^the invention can comprise other characteristics that can be taken separately or in combination, including:

the procedure for updating the current location area of a mobile terminal in standby mode can be automatically performed by the network (for example by its core network) only when this mobile terminal changes location area,

- the connection ^of a terminal to a point ^of local radio access can be done by correlating received signals with associated access codes respectively to points ^of local radio access;

> The connection ^of a terminal to a local radio access point can also be done by analyzing the power of signals transmitted by the points ^of local radio access and by selection ^of the point of local radio access emits yes your signals are more powerful;

• when a terminal in idle mode enters the radio coverage area ^of an ^access point local radio, and in case of reception by the terminal is also connected to a radio access point (or station basis) ^of a cell from signals transmitted by the radio access point by a power greater than those of signals emitted by the ^access points local radio, the network can remove the connection between this finished! and this radio access point, to constrain the terminal to connect to the local radio access point whose signals are the most powerful among those emitted by the local radio access points;

I finished it! may analyze the received radio spectrum and perform correlation of received signals with his access codes are respectively associated with ^of focal radio access points located in Îes cells that are part of the known location area in which it is located;

> Alternatively, the terminal can analyze ie received radio spectrum and perform correlation of received signals with the ^access codes which are respectively associated with points ^of local access radio whose geographic positions associated are contained in the known location area in which is located;

the access codes of the local radio access points which are located in the cells which are part of the known localization zone in which it is located can be transmitted to a terminal;

> alternatively, we can transmit to a termina! the access codes of all your local radio access points which are located in the cells of the network;

Once the procedure for updating the location area of a terminal is completed, this terminal can be forced to transfer its connection to a radio access point of the cell in which the point of origin is impinged ^. Loca radio access! s to which it ^is connected.

The ^invention also provides a system dedicated to the location of radio communication terminals in veilie mode in a network cellular radio communication subdivided into location zones associated with area identifiers and having at least one cell. This system is characterized by the fact that it includes:

- at least one local radio access point, located in a cell ^of a location area having a radio coverage area of upper surface to its _own, and associated with a different region identifier that of the location area of which is part of his cell,

- connection means adapted, when a communication terminal in standby mode radio enters the radio coverage area of the local radio access point, retrieve ^the zone identifier of that access point local _radio, and connect this terminal to this local radio access point, and

update means responsible for initiating at the level of this terminal a procedure for updating a location area within the network with the retrieved area identifier, so that the network associates with this terminal the identifier recovered area.

The system according to the invention may comprise other characteristics which may be taken separately or in combination, and in particular: its connection means may be responsible for analyzing the received radio spectrum and correlating the received signals with codes; ^access respectively associated with ^access points local radio, so as to connect a terminal into one of these local radio access points; Its connection means may be responsible ^for analyzing the power of the signals emitted by the local radio access points received by Terminates! and connect the latter to the locai radio access point which transmitted the received signals with the greatest power;

* Its connection means can be loaded, in case of deletion by the network of a connection between a terminal and a radio access point of a cell consecutively upon reception by this termina! signals transmitted by the radio access point by a power greater than those of signals from local radio access points, to connect this terminal to the point ^of local radio access whose signals are most powerful among those emitted by ^points focal radio access;

> Its connecting means may be adapted to ^analyze the received radio spectrum and to perform a correlation of received signals with ies ^access codes which are respectively associated with the local radio access points located in ies cells that are part of area ia of known location in which the terminal is located; y alternatively, its connecting means may be adapted to ^analyze the received radio spectrum and to perform a correlation of received signals with the ^access codes which are respectively associated with points ^of local radio access whose geographic positions associated are contained in the known location area in which the terminal is located.

The invention also relates to a radio network controller, i) for forming part of a radio communication network, ii) capable of controlling at least one radio access point ^of a celiule of the network in which is located in the least one local radio access point, and iii) arranged, when a radio communication terminal (in standby mode and connected to this point ^of the cell radio access) enters the radio coverage area of the point of local radio access, and in the event of reception by this terminal of signals transmitted by this radio access point under a power greater than those of the signals emitted by the local radio access point, to order the deletion of the connection between the terminal and point ^radio access, so as to force the terminai to connect to the radio access point focai.

The invention also relates to a focal base station, ^a first part, intended to act as a point ^of local radio access in a cell of a location area (having an area of radio coverage area higher than its own, associated with a zone identifier and part of a network, radio communication), and a second part, associated with an area identifier different from that of this focusing area which includes its cell, and ά'une third party arranged when a standby radio communication terminal has attached itself to and a focus area update procedure has been performed within the network for that terminal with its own zone ID, to constrain the termina! to transfer its connection to a radio access point of this eye.

Other features and advantages of the invention will appear on ^examining ia detailed description below and the accompanying drawings, wherein:

FIG. 1 very schematically and functionally illustrates a cellular radio communication network comprising two location zones and a location system according to one embodiment of the invention, and

- Figure 2 schematically iiSustre Its main messages exchanged between the network equipment and mobile terminal Sors ^a procedure for locating the mobile terminal according to an embodiment of the invention,

The attached drawings may not only serve to complete the invention, but also contribute to its definition, if any.

Linvention aims to allow the localization with good precision ^of a radio communication terminal in standby (or idle) in a cellular radio communication network.

In what follows, it is considered as a nonlimiting example that the cellular radio communication network (RC) is a so-called "3G" network, such as for example a UMTS or CDMA 2000 type network. is not limited to this type of cellular network. It concerns indeed any type of cellular network that can implement the invention.

Furthermore, it is considered in the following, by way of non-limiting example, that the radio communication terminals (Ti) are mobile phones (or cellular). However, the ^invention ^is not ϋmitée this type of radio communication terminal. It concerns indeed any type of radio terminal (trans) carried by a mobile user, including laptops and digital personal assistants (or PDAs) capable of communicating via a radio link (eg type 3G).

FIG. 1 shows schematically an exemplary RC cellular network. This type of RC cellular network can, in a very schematic but nevertheless sufficient for understanding the invention, be summarized in a network of heart (or "Core Network") CR coupled to a network ^of radio access RAR.

The radio access network RAR firstly comprises nodes (radio network controllers) NC coupled to the core network CR, via an interface (called a lu), and called RNC (for "Radio Network Controller"), in the case ^of a UMTS network, and BSC (for "Base Station Controller"), in the case ^of a GSM or GPRS network. It also includes radio base stations or access points (transmission ^/ réceptionj SBjk which are, firstly, associated (s) each (e) at least one Cjk cell having a radio coverage area, and, secondly, coupié (s) one (s) or in groups of at least one ^one of the above nodes NC via a logical interface (called lub). These base stations are called SBjk mode B, in the case of a UMTS network, and BTS, in the case ^of a GSM network (GPRS),

The radio access network RAR is further subdivided into zones of localization (or "localization areas") ZLj which each include a set of at least one cell Cjk and which are each associated with a clean area identifier (or LAC ( for "Locaiization Ares Code")) IZj.

In the nonlimiting example illustrated in FIG. 1, the cellular network RC comprises two localization zones ZL 1 and ZL 2 (J = 1 or 2). The first location area ZL1 groups two cells C11 and C12 (j ≈ 1 and k - 1 or 2) which are both associated with the area identifier iZ1 of their location area ZL1 and whose base stations SB11 and SS 12 respectively broadcast this zone identifier IZ1 on their respective BCCH beacon channels. The second location area ZL2 groups together three cells C21, C22 and C23 (j = 2 and k = 1 to 3) all of which are associated with the area identifier IZ2 of their location area ZL2 and whose base stations SB21, SB22 and SB23 respectively broadcast this zone identifier SZ2 on their respective BCCH beacon channels.

The ^invention proposes in particular to implant in at least some cells Cjk RAR radio access network, and possibly all, of raάlo local access points FBjKn freely available (or in English "open access") coupled to the aforementioned NC nodes (radio network controllers (BSC or RMC)) and each having a significantly smaller radio coverage area than that of the SBjk base station of their Cjk cell. It should be noted that these local radio access points FBjkn are sometimes called "femto BTS" and constitute femto FC cells (in this case they are said to be associated with sub-cells called "femto cells" and constituting sub-parts of cells called "macro cells"). In FIG. 1, only two femto FC cells have been shown so as not to overload the design.

It will be understood that each local radio access point FB _j kn constitutes for a terminal, because of its free access, a network equipment similar to a base station (or radio access point) SBjk and thus allowing it to access the RC network. It is recalled that a conventional Femto BTS is usually designed to provide residential access, ie limited to a limited and predetermined number of users. Therefore, each local radio access point FBjkn also has a beacon channel (BCCH) which allows it to broadcast in its (femto) radio coverage area useful information to the terminals Ti to connect to the RC network or to continue ongoing communications. However, unlike a base station SBjk that is associated with ^the area identifier IZj from his area cfe ZLJ location, so that broadcasts in the (macro) radio coverage of this identifier IZj area, an access point raύ ^io local FBjkn is associated with a IZ'jkn area ID which is the same type as i'ideπtifiant of IZj region of its location area ZLJ but differs from the latter and of those location areas ZLJ (J '≠ \) neighbors. Therefore, an ^access point FBjkn focal radio according to the invention, broadcasts on its broadcast control channel (BCCH) the identifier of IZ'jkn area that has been specifically associated with it and not that of its ZLJ location area. i! It is important to note that the geographical position of a FBjkn local radio access point is well known to the RC network. Therefore, when ^one knows the identifier of IZ'jkn area that is specifically associated with an ^access point FBjkn local radio can be determined within the RC network the corresponding location of this local radio access point FBjkn.

Therefore, when a terminal Ti (in standby mode) is located in a cell Cjk and that ^it ^s' is already registered with the RC network by providing the zone identifier IZj of the focusing zone ZLj to which this cell Cjk belongs, then, when it is in the radio coverage area of a local radio access point FBjkn of this cell Cjk, it can recover (receive) the zone identifier IZ'jkn of this focal radio access point FBjkn.

The terminal Ti includes connection means MC in particular comprising receiving means adapted to receive ies radio signals transmitted by the network equipment ^of RAN radio access, analyze these received radio signals (the radio spectrum) and recover (After demodulation) the information that is contained in these demodulated signals, including a possible zone identifier IZ'jkn of a local radio access point FBjkn.

When the retrieved area identifier IZjkn is different from that (IZj) of the location area ZLj in which the terminator Ti is located (and to which its terminal identifier (for example an IMS!) Has been previously associated by the network RC at the time of recording), then said terminal Ti is forced to connect to the local radio access point FBjkn (by means of its connection means MC) in order to allow update means MM which it comprises of ^initiate proceedings "classic" setting â location area update ( "location area Code update" (or LAC_Update) - 3GPP standardized procedure) to the RC network with this area ID IZ'jkn recovered. It is recalled that during this update procedure the RC network will replace the IZj zone identifier Its location area ZLJ, ^until then associated with terminal Ti by the newly reclaimed area by identifying IZ'jkn the latter (Ti).

Thus, once ^the identifier (I ¹ free IMSI) of a terminal Ti is registered with the RC network in correspondence with the area identifier IZ'jkn a local FBjkn radio access point, it is possible to know with a margin of error (very) limited the geographic location of the terminal Ti, since the margin of ^error is at most equal to the "radius" (schematically speaking, if we approximate the cell radio coverage Cjk to a circle) of the radio coverage area of the local radio access point FBjkn.

It is recalled that in a 3G RC network the identifiers (for example IMSi) of the registered Ti terminals are generally stored in correspondence SZJ area IDs in CR network equipment called the heart GMLC ( "Gateway Mobile Location Center") or a GM ^of customer information database HV (including position) called HLR ( "Home Location Register" ). It is also recalled that this recording (in the domain is CS) ₁ as well as each location location update procedure, involves several other network equipment of the core network CR, such as for example at least one node (or equipment). ) called MSC / VLR ("Mobile Switching Ceπter / Visited Location Register").

FIG. 2 schematically illustrates the main messages that are exchanged between the above-mentioned network devices (SBjk, FBjk, SGSN, HV and GMLC) and a terminal T1 during a procedure for locating the latter (Ti).

Here it is considered that the TI terminal is in standby mode (idle), is located in the first cell C11 of its first location area ZL1 of the RC network and has already registered with said RC network in association with identifier zone IZ1 of this first location zone ZL1. Therefore, the identifier (! MSI) of the termina! T1 is stored in correspondence of the zone identifier IZ1 in the GMLC equipment (here referenced GM). It is also contemplated that the terminai T1 just entered within the (femto) radio coverage area of the second ^point FB112 focal radio access of the first cell C1 1 and therefore it receives both Ie cana ! beacon of the base station SB11 of the first cell C11 (arrow F1) and the beacon channel of the second radio access point ioca! FB112 (arrow F2). So it can recover ^the ID iZ'112 area than second local radio access point FB 112 broadcasts its beacon channel (arrow F2).

As mentioned above, the termina! TI comprises connection means MC loaded, in particular, to recover in the radio signals received zone identifier iZ'112. These connection means MC perceiving that this identifier IZ'112 area ^is not one (1Z1) which is associated with their terminai T1, they connect its terminal 11 to the second ^access point FB112 local radio (arrow F3).

Once the connection is established between the terminal TI and the second point. ^access FB112 local radio, update means MM that in ^'comprises initiating a location area update procedure within the RC network with the area identifier recovered IZ'112, so that of other means of update MM (complementary) of the network RC associate with the termina! T1 this retrieved area identifier. It is understood that such alternative means of updating MM are responsible for replacing it with ^the Zone ID ÎZ'1 12 recovered ^the IZ1 area identifier of the ZL1 location area that was previously associated with the RC network to the terminal tl

As partially illustrated in FIG. 1, the other update means MM are in particular distributed in its local radio access points FBjkn, the SBJk base stations, the NC radio network controllers, and the equipment (nodes) MSCΛ / LR. , and the HV database (HLR).

It will be appreciated that local radio access points FBjkn, your means MM update and connection means MC together constitute a positioning system according to an embodiment of ^the invention.

As is well known to those skilled in the art, the update procedure is routed in five successive parts when it concerns the CS domain. It should be noted that this update procedure is in particular standardized. It is for example described in the book "The Origins UMTS, ^{architecture,} ia standard" Peter Lescuyer, 2nd edition, Dunod Edition, including ia section 8.2.2 on "The upgrade in the Location Area CS domain ".

W is recalled that at least one location area is associated with a node (or equipment) MSCΛ / LR. Since the zone identifier of an iocal radio access point FBjkn is different from the zone identifier of the location zone ZLj comprising this focal radio access point FBjkn, the latter and its location zone ZLj can therefore be attached to either the same MSCΛ / LR equipment or to different MSC / VLR equipment. The following is considered in the case where the local radio access point FBjkn and its location area ZLj are attached to different MSCΛ / LR equipment.

In this non-limiting case, the first part IA procedure updated (arrow F4) comprises forward terminai Tt to the (new) MSC node / VLR which is associated with the second ^access point iocal radio FBI I 2 { via te second local radio access point FB 112, the base station SB11 and the NC radio network controller which is coupled to the base station SB11) an update message, for example of the type "LAC Update (TLLi)". TLLi stands for "icallogical Link Identifier" and designates a signaling address.

The second part of the update procedure (arrow F5) is to exchange update messages between the new MSC / VLR node and the old MSC / VLR node, in a secure manner, so that the new MSC node / VLR retrieves information on the T1 terminal and the old MSC / VLR node deletes the record relative to said T1 terminal.

The third part of the update procedure (arrow F6) is to update the HV database (HLR) with the new zone identifier IZ'112. This can for example be done by transmitting an update message, for example of the type "LAC Update (lMSl, iZ'1 12)" between the new node MSC / VLR and the database HV (HLR). It will be understood that the new MSC / VLR node is arranged to determine for example the IMSI identifier corresponding to the TLLI of the terminal T1 and the area identifier IZ ⁵¹¹² which corresponds to ^the access point identifier (Femîo CeIJ Id) of the second local radio access point FB112. In particular, it has a correspondence table for this purpose.

The fourth part (arrow F7) consists in transmitting from the new MSC / VLR node to the terminal TI an update message intended to inform it of the success of the location area update procedure that it has initiated.

The fifth part (Fδ arrows F9) is to release the connection (RRC) ^until then established between terminal T1 and ie the base station S811. To do this, the new node MSC / VLR can for example address (arrow Fδ) a message to the radio subsystem (or RNS ("Radio Network Sub-system")), and for example to the radio network controller NC which controls the base station SB11, to order it to release the connection due to an attachment of the terminator TI to another radio access point (here the second local radio access point FBi 12), then the network controller For example, an NC radio may send (arrow F9) a message to the base station SB11 instructing it to release the connection established with the terminator T1. The HV database (HLR) Ayani been updated, it can then, if it is asked by an authorized application (oυ a ^server authorized applications), communicate to it (or it) the geographical position of the terminal T1 which corresponds to the access point identifier (Femto CeII ID) of the second local radio access point FB112. fl has for example for this purpose with a table of correspondence between geographical positions and ^access point identifiers.

We will now detail how a T1 terminal (in standby mode) proceeds to connect to a local radio access point! FBijk of a cell Cjk, so who! is already attached to the base station SBjk of this cell Cjk.

For a terminal Ti, located in a ceifufe Cjk and attached to the base station SBjk of the latter (Cjk), can connect to a local radio access point FBjkn of this cell Cjk, it is necessary that il listen to the frequency on which the cana is sent! baiise this ^access point FBjkn local radio. It is therefore advantageous that within the same cell Cjk, the base station SBjk and the different local radio access points FBjkn transmit their channel on the same frequency. It is also necessary that the termina! Ti has access codes, for example CDMA codes in the case of a UMTS network, respectively associated with the local radio access points FBjkn. Thus, the receiving means of the terminal Ti, that are part of its connection means MC, can sweep the radio spectrum received by correlating successively received signals with His different ^access codes, here CDMA, they have, on the frequency ^emission of local wireless access points FBjkn.

It will be noted that ^a terminal Ti may for example n ^'use for its scanning the radio spectrum, the ^access codes which are respectively associated with points ^of local FBjkn radio access which are located in different Cjk cells that are part of the known location zone ZLj in which it is located, or even only of the cell Cjk in which it is momentarily located.

For this purpose, the network RC may for example transmit to a number of terminals Ti which have registered with it its access codes of the local radio access points FBjkn which are located in its cells Cjk belonging to the ZLj known location areas in which they are located respectively. The base station SBjk Cjk each cell can for example be responsible for the radio broadcast of the ^access codes at least the access points of its Cjk cell.

Alternatively, a terminal Ti may for example be used for the scanning of radio spectrum, the access codes are respectively associated with points ^of local radio access FBjkn associated with geographical positions are contained in the region of localization ZLj known in which it is located, or even only the cell Cjk in which it is momentarily located.

To do this, the RC network can for example be transmitted to terminals Ti which are registered with read access codes local radio ^access point FBjkn whose geographical positions are included in ies areas ZLJ known location in which they located respectively. For example, the base stations SBjk of each location area ZLj may be responsible for the radio broadcast of the access codes of the access points of their own location area ZLj.

Alternatively Note that the terminals Ti can eg store the access codes of all ies local points ^of FBjkn radio access that are implanted in Cjk cells RC network to which they are attached. These access codes are for example transmitted to them by the SBjk base stations of the RC network. In this case, the terminal Ti (in veiile mode) will select among all the access codes ^that it stores those which correspond to radio access points that are implanted into the ZLJ location area in which it is located . This requires, for example, the Ti devices store the mapping access codes IZj area identifiers of ZLJ location areas in which are located the ^points associated FBjkn local radio access.

The connection phase of a Ti terminal to a point ^of local FBjkn radio access may also comprise, in addition to scanning for access codes, an analysis of the power of signals transmitted by the points ^of local radio access FBjkn. This analysis is intended to select the local radio access point FBjkn which transmits the signals which are received by said terminal Ti with the highest power. These most powerful signals are in fact, a priori, those which are emitted by the local radio access point FBjkn which is the closest to the terminal Ti considered, and therefore which will make it possible to know with the smallest margin of error the geographical position of the terminal Ti.

It is important to note that in some cases it may happen ^that _a finished t {Ti in veilie mode) attached to a point ^of radio access network (or base station) SBjk Cjk a cell receives signals transmitted by the ^access point SBjk radio at a power which is higher than those of the signals transmitted by the points ^of local radio access FBjkn. In a conventional mode of operation _, the terminus Ti should normally continue to remain attached to this base station SBjk since it is this which offers the most power. Therefore, in this situation the invention could not be implemented.

In order to remedy this drawback, the network RC (and more precisely its radio access network RAR) can for example eliminate the connection between a terminal Ti and its radio access point SBjk home. This deletion can for example be done at the request of the radio network controller NC which controls the radio access point SBjk attachment of the terminal Ti.

Note that the RC network does not know the difference between a terminal Ti in connected mode, attached to a radio access point SBjk and a terminator Ti in standby mode, attached to a radio access point SBjk. Consequently _, the deletion of the connection or the radio link is imposed for all the terminals Ti which are in the theoretical geographical or radio coverage of a radio access point SBjk.

For the connection release command is given (tripped), for example by a radio network controller NC, must Ie RC network is aware of the entrance ^of a terminal Ti in the coverage area of FC ^a local radio access point FBjkn. For this purpose and failing to be able to finely locate the terminal Ti. two mechanisms, not necessarily exclusive, can be used.

A first mechanism is to use the stored ^access codes that correspond to the current location area of ZLJ finished! Ti and from which one can deduce the associated access code to all points ^of local radio access FBjkn this ZLJ location area, to scan all received radio signals may emanate of points ^of local radio access (corresponding to these codes ^access). If reception of the signals from ^one of these radio access points iocaux FBjkn is above a certain threshold and if reception history attendance local radio access points FBjkn (stored in a memory local) shows at least one previous attendance with it, it is considered statistically that the user carrying the terminus Ti will be introduced into a place (or zone) in which is implanted said local radio access point! FBjkn. This consideration may be corréiée with known profiling mechanisms (eg memorizing profiS ^the user of the terminal Ti and correlation with the interest that user could wear instead (or Her area)) to deduce the point ^radio access loca! FBjkn to which the terminal Ti must hang.

A second mechanism consists in using the satellite location function (for example of GPS type) of a terminator Ti (if it has one) to determine (estimate) its position and its velocity vector, then to predict its input ( or not) in the coverage area of a local radio access point FBjkn based on this position and this velocity vector.

Once a terminal Ti clung to an ^access point FBjkn local _radio, it deletes the connection (or link) with the radio access point SBjk Cjk of the cell where it is implanted ^access point local radio FBjkn. This deletion is performed by the radio access point SBjk by order of its NC radio network controller.

By the way, to avoid that the termina! Ti reconnects (attached) back to the base station SBjk its Cjk ceilule just after logging in (attached) at an ^access point FBjkn local radio that his power is greater than that of this point ^local radio access FBjkn. it is conceivable to introduce a kind of "hysteresis" mechanism that prohibits the terminal Ti such a reconnection for a chosen period of time (sufficient to allow the location location update procedure to be performed in full - for example, at least two seconds) and / or as a function ^of a maximum threshold power.

In addition, once the procedure for updating the location area of a terminal Ti is completed, it is also possible to constrain the terminal Ti to transfer its connection to the radio access point SBjk of the cell

Cjk in which is implanted the local radio access point! FBjKn he just connected to (connect). To do this, the point ^of local FBjkn radio access may for example send a message to the terminal Ti ordering him to disconnect from it to be attached to the radio access point ia SBjk of cell

Cjk in which he is momentarily located. This end of connection message can for example be addressed to the terminal Ti by the local radio access point

FBjkn after expiration of a timer, for example ^lasting a few seconds. This transfer constraint is intended to rapidly discharge points ^of local access radio FBjkn because they can not usually withstand a few connections simultaneously, typically less than five (especially ^when they are involved in a communication), unlike stations base SBjk whose connection capabilities are much larger.

In addition, in order to prevent a local radio access point FBjkn from polluting a SBJk station on the radio plane, it may be envisaged that this local radio access point could be used. FSjkn is equipped with directional antenna (s) pointing to selected directions, for example only to the entrances and / or exits of a shop.

The connection means MC and / or the update means MM according to the invention can be implemented in the form of electronic circuits, software (or computer) modules, or a combination of circuits and software. Advantageously, the connection means MC may consist of one or more software modules, possibly standardized.

The invention is not limited to the localization system, local radio access point and radio network controller system and method embodiments described above, by way of example only, but encompasses all variants that may consider those skilled in the art within the scope of the claims below.

Claims

A method of locating radio communication terminals (Ti) in a trunk mode in a cellular radio communication network (RC) subdivided into location zones (ZLj) associated with zone identifiers and comprising at least one cell (Cjk), characterized in that ^it comprises, when ^a radio communication terminal (Ti) in the standby mode enters a radio coverage area of a radio access point Locas (FBjkn), located in a cell (Cjk) of a location area (ZL) having a radio coverage area with a surface area greater than its own, and associated with a zone identifier different from that of this location area (ZLj) including its cell (Cjk): a retrieving step ^of identifying said local area radio access point (FBjkn)

- a connection step of this termina! (Ti) to said locai radio access point (FBjkn), and

- a step ^of initiation by said terminai (Ti), a procedure for making the location area update to said network (RC) with said recovered identifier area, such that said network associated with said terminated! (Ti) said retrieved area identifier.

2. Method according to claim 1, characterized in that said procedure for updating the current location area of a terminal (T1) in standby mode is automatically performed by said network (RC) only when said terminal (Ti ) changes location area,

3. Method according to one of Claims 1 and 2, characterized in that the connection of a terminal (Ti) to an ^access point local radio (FBjkn) is effected by correlation of received signals with associated access codes respectively at local radio access points (FBjkn).

4. Method according to claim 3, characterized in that the connection of a terminal (Ti) to a local radio access point (FBjkn) is also done by analyzing the power of the signals emitted by the radio access points local (FBjkn) and by selection or ^access point radio room (FBjkn) emitting His strongest signals.

5. A method according to claim 4, characterized in that, when a terminal (Ti) in the standby mode enters the radio coverage area ^of a local radio access point (FBjkn), and in case of reception by the terminal (T) connected to a radio access point (SBjk) ^of a cell (Cjk) of signals transmitted pat- this radio access point (SBjk) as a power greater than those of signals emitted by the points local radio access (FBjkn), said network (RC) deletes the connection between iedit terminated! (Ti) and said point ^of radio access (SBjk), so as to force said terminal (Ti) to connect to the ^access point radio iocaf (FBjkn) whose signals are Its most powerful among those emitted by said points local radio access (FBjkn).

6. Method according to one of Claims 3 to 5, characterized in that said terminai (Ti) analyzes the received radio spectrum and makes a correlation of received signals with the ^access codes which are respectively associated with radio access points local (FBjkn) implanted in the cells (Cjk) which are part of the known location area (ZLj) in which it is located.

7. Method according ^to one of Claims 3 to 5, characterized in that said terminal (Ti) analyzes the received radio spectrum and makes a correlation of received signals with the access codes which are associated with radio access points respectively local (FBjkn) whose associated geographical positions are contained in the known location area (ZLj) in which it is located.

8 _. Method according ^to one of Claims 3 to 7, characterized in that it transmits ^to a terminal (Ti) the ^access codes of ^the points of local access radio (FBjkn) which are located in cells (Cjk) forming part of the known localization area (ZLj) in which it is located.

9. Method according to one of Claims 3 to 7, characterized in that it transmits ^to a terminai (Ti) access codes from all points ^of local radio access (FBjkn) that are implanted into the cells (Qk) of said network (RC).

10. A method according to one of claims 3 to 9, characterized in ^that once! Â lour a procedure of setting the location area

terminal (Ti) is completed, said terminal (Ti) is forced to transfer its connection to a radio access point (SBJk) of the cell (Cjk) in which is implanted the local radio access point (FBjkn) to which it has connected .

11, Method according to one of claims 1 to 10, characterized in that one associates said terminal (Ti) the geographic position which is associated with the area identifier of said retrieved ^access point local radio (FBjkn) to which it is to connect.

12. System for focusing radio communication terminals (Ti) in standby mode in a cellular radio communication network (RC) subdivided into location zones (ZLj) associated with zone identifiers and comprising at least one cell (Cjk) characterized in that it comprises:

at least one local radio access point (FBjkn) implanted in a cell (Cjk) of a location area (ZLj) having a radio coverage area with a surface area greater than its own, and associated with a zone identifier different from that of the location area (ZLj) of which its cell (Cjk) is part,

connection means (MC) arranged, when a radio communication terminal (Ti) in standby mode enters the radio coverage area of said local radio access point (FBjkn), to recover said zone identifier of said local radio access point (FBjkn), and to connect this terminal (Ti) to this point. local radio access (FBjkn), and

- Update means (MM) arranged to initiate at said terminal (Ti) a location area update procedure within said network (RC) with said retrieved area identifier, so that said network ( RC) associates with said terminal (Ti) said retrieved area identifier.

13. System according to claim 12, characterized in that said connection means (MC) are arranged to analyze the received radio spectrum and correlate the received signals with associated access codes respectively to beautiful radio access points ^. (FBjkn) so as to connect a terminal (Ti) to ^one of these points ^of local access radio (FBjkn).

14. System according to claim 13, characterized in that said connection means (MC) are arranged to analyze the power of the signals from its said points ^of local radio access (FBjkn) and received by said terminal (Ti) and for connecting the latter (Ti) to the radio access point Ioca! (FBjkn) which emitted the signals received with the greatest power.

15. The system of claim 14, characterized in that said connecting means (MC) are arranged, in case of removal by said network (RC) of a connection between a terminal (Ti) and a point ^radio access ( SBjk) of a cell (Cjk) following the reception by the terminai (Ti) signals transmitted by the radio access point (SBjk) soυs a power greater than those of signals emitted by the points ^of local radio access ( FBjkn), for connecting said terminal (Ti) to the local radio access point (FBjkn) whose signals are the most powerful among those emitted by said local radio access points (FBjkn).

16. System according to one of Claims 13 to 15, characterized in that said connecting means (MC) are arranged to analyze the received radio spectrum and to perform a correlation of the received signals with the ^access codes which are associated with points, respectively local radio access means (FBjkn) implanted in the cells (Cjk) which are part of the known location area (ZLj) in which said terminal (Tt) is located.

17. System according to one of claims 13 to 15, characterized in that iesdits connection means (MC) are arranged to analyze the received radio spectrum and to perform a correlation of the received signals with the ^access codes which are respectively associated at points ^of focal radio access (FBjkn) whose geographic positions associated contained in the location area (ZLJ) known in which said finished! (Ti) is located.

18 _. Focal base station (FBjkn) to act as an ^access point radio Ioca! in a cell (Cjk) ^of a location area (ZLJ) having an area of radio coverage area higher than its own, associated with an area identifier and part of a radio communication network (RC), characterized in qu'eue this is associated with a different area identifier of one of said location area (ZLJ) which includes the cell (Cjk), and in that it is arranged, when ^a radio communication terminal (Ti) mode standby ^s' is attached to it ei that ^a location area update procedure has been performed within said network (RC) for said terminal (Ti) with its zone identifier, to constrain the terminal (Ti) to transfer its connection to a radio access point (SBjk) of said cell (Cjk).