WO2009138683A2 - Managing a wireless network - Google Patents

Abstract

The present invention relates to the management of a wireless network. The network comprises a plurality of access points (BSI l, BS21,...), to each of which is allocated an identifier used for a communication with a terminal (TER) served by the network. Within the meaning of the invention, a part at least of these identifiers of access points are variable over time. In practice, network equipment such as switching centres (BSC1, BSC2) in a GSM network can manage the assigning of the temporary identifiers of access points and synchronization of these assignments may be centralized by a management unit of a database of the subscriber terminals (HLR).

Description

 Management of a wireless network

The present invention relates to the technique of telecommunication networks, in particular wireless access networks for communications on mobile terminals.

A current technical issue concerns the means for geographical location. As an example of a wireless network, a cellular network (for example of the GSM type) comprises a plurality of base stations as access points and a terminal in a mobility situation can communicate via one or more base stations. successive. At each communication via a given base station, the terminal can receive an identifier of this given base station.

It is then possible today to locate a mobile terminal in a cellular network, by determining the current base station through which it can establish a communication or benefit from a service (for example type SMS, MMS, or other). The operators of wireless telecommunication networks have the advantage of knowing the topology of their networks and can then seek to value their exclusivity relating to the provision of location information "to the cell".

However, other actors already offer this type of location, strong learning that they can do cell positions. Indeed, mobile terminals arranged to communicate for example with a cellular network may be further equipped with a GPS positioning system. Since, usually, a mobile terminal receives a cell identifier (or base station covering this cell), such a terminal may be able to establish a correspondence between a current cell identifier (available at the terminal and therefore quite easily recoverable) and the approximate position thereof. With a certain number of "GPS positioning / cell identifier" couples that may be communicated to a third party, this third party may determine all or part of the geography of the cells of a operator and even potentially resell this approximate knowledge of the network topology of the operator, to other third parties.

Thus, a third party can be aware of the topology of the network of an operator, and this without the knowledge of the operator manager and guarantor of its network. This third party can for example identify the movements of the wearer of a given terminal, deduce his habits or otherwise, which poses a problem of infringement of the freedom of individuals carrying terminals and possibly incurs the responsibility of the operator.

There is no known way today to prevent the transmission of cell identifier information to the third party. This information resides both in the network and in the terminal: it is necessary for the establishment of calls and other telecommunications services, which makes it difficult for the operator to protect this precise location information of the access point. In addition, this information is quite easily accessible on mobile terminals, which can further facilitate, possibly without the knowledge of users, network topology reconstructions by third parties.

In addition to the problem of infringement of the freedom of the aforementioned terminal users, the network operator loses its exclusivity on the geographical distribution information of the access points of its network.

The present invention improves the situation.

For this purpose, the present invention firstly aims at a method of managing a wireless network, the network comprising at least one access point, the method comprising the assignment to said at least one access point of an identifier used for a communication with a terminal, characterized in that said at least one access point identifier is variable in time.

According to the invention, at least one access point identifier is variable in time. Thus, it is proposed to protect the knowledge of the location of the access points for third parties by making the network topology opaque by means of a dynamic addressing mechanism (variable in time) of the access points of the network.

The assignment of the variable identifiers is preferably carried out by at least one device in charge of managing at least part of the access points of the network. It may be for example a module integrated into a network switching center (so-called "MSC" equipment for "Mobile Switching Center") or a base station control (equipment called "BSC" for " Base Station Controller "). As a reminder, an MSC exchange is responsible for routing communications in the network and / or interconnection with other networks and / or coordination of calls.

According to a variant of the method, a variable identifier is unique. In this way, it is avoided to assign the same identifier to separate access points, especially when they are managed by different devices.

According to one variant, the method comprises a step of storing a correspondence table comprising at least one correspondence between an immutable identifier assigned to an access point, and a temporary identifier of said variable access point in time. Thus, each time a variable identifier is received, a match is made with an immutable identifier to identify the access point concerned by the received identifier. Note that the immutable identifier is usually assigned initially to the access point.

The present invention also aims at a wireless network equipment, in charge of managing at least one access point of the network, characterized in that it comprises means for assigning a variable identifier over time to a respective access point.

The present invention also relates to a computer program, comprising code instructions for implementing the method of the invention defined above, when executed by a processor for example present on the equipment defined above ..

In an embodiment according to which the network comprises a plurality of equipment in charge of management of access points, the allocation of the variable identifiers can advantageously be controlled by a synchronization unit to avoid attributing the same identifier to points access and managed by different equipment.

Such a synchronization unit may be integrated in a management entity of a central database of the network comprising information relating to subscriber terminals able to move in the network and to communicate with points of interest. network access. For example, this entity can manage the database corresponding typically to the register HLR (for "Home Location Register") in a conventional GSM network.

The present invention thus aims at a synchronization unit of a wireless network, arranged to receive information for assigning access point identifiers and for transmitting, for example, a synchronization request message to one or more pieces of equipment. management of access points when assigning the same identifier to several different access points. The present invention is also directed to a computer program, comprising instructions for implementing a synchronization of the identifiers assigned to the access points, when this program is executed by a processor of such a synchronization unit.

The present invention also relates to a system in a wireless network, the network comprising at least one access point managed by at least one device, characterized in that at least one device comprises means for assigning a variable identifier over time. at a respective access point. Advantageously, the system also comprises a synchronization unit for assigning access point identifiers of the aforementioned type. Other features and advantages of the invention will appear on examining the detailed description below, and the attached drawings in which: FIG. 1 schematically illustrates the elements involved in a network management system in the sense of the Figure 2 schematically illustrates the contents of a look-up table that stores a device assigning time-varying identifiers to access points.

In what follows, a cell-type network in which each access point is a base station BSI 1,..., BS32, each serving a cell of the network as illustrated in FIG. 1, is considered as an example. Here, a group of base stations BSI 1, BS21, BS31 (or BS12, BS22, BS32) is connected to a base station controller BSC1 (or BSC2). For the voice or SMS communication relay, each base station controller BSC1, BSC2 is connected to a central office MSC (for "Mobile Switching Center") and each exchange MSC1, MSC2, and so on. (Figure 1) is connected to a management entity of a register HLR (for "Home Location Register"), or, alternatively, an entity in charge of a register VLR (for "Visitor Location Register") . Such an HLR register corresponds to a database containing the information relating to the user subscriber terminals of the network such as, for example, the cell in which they were located during a last interrogation, in particular to enable efficient re-routing of the data. calls or data transfers.

The invention proposes to use a mechanism for changing the name of the dynamic identifier of the base stations so as not to reveal their real and immutable identifier. The term "immutable" means that the temporary identifier (alias) of the access point can evolve at a frequency much higher than the identifier initially assigned to the access point (hereinafter referred to as "immutable identifier") . In addition, a frequency of change / update of the station identifiers is provided in order to ensure periodic renewal to make the proposed mechanism more robust. This mechanism is preferably controlled from the heart of operator network and can typically be managed by an entity of the network subsystem such as, for example, a switching central office MSC in a conventional GSM network for voice or SMS communication, or an SGSN node of the network subsystem. network (for "Serving GPRS Support Node", with GPRS for "General Packet Radio Service") for data communication in a packet-oriented network, for example.

In a mobile network, the base station identifier (more commonly called "cell identifier") is used in particular for the needs of the station, for example to ensure search mechanisms (better known as "paging" by the person skilled in the art) of a mobile terminal in the network, or for setting up calls or any other telecommunication service.

The solution proposed in the sense of the invention is that a network equipment (such as for example an MSC entity) can change the identifier of the cell regularly, for example periodically or randomly but synchronized. The correspondence between the unique and immutable identifier of a cell and its temporary identifier (hereinafter called "alias") is preferentially maintained in a correspondence table stored for example in memory of this MSC equipment. Periodically, the "master" equipment (such as the MSC equipment) regenerates an identifier for each of the cells attached to it. To avoid possible collisions of identifiers (cases of access points that would temporarily and accidentally have the same alias), the equipment managing the aforementioned correspondence table synchronizes and synchronizes its own correspondence table with other equipment managing analogous correspondence tables (other MSC entities of the network for example). Another network entity, such as for example an HLR registering entity may be in charge of the global synchronization between all the MSC equipment of the network.

Advantageously, an access point is configured, within the meaning of the invention, to receive and accept (therefore be assigned) the temporary identifier as soon as it is generated for this purpose. access point, and then transmit it to the mobile terminals covered by this access point.

A request (authorized by the operator) for locating a mobile terminal TER in the cellular network can be treated substantially as in the sense of the prior art, without the alias assignment disturbing the location of this terminal. It describes how such a request is processed, which can come from an element of the network itself (for example the entity managing the update of the HLR register), or from an element outside the network. In this second case, it is then considered that the REQ request (as illustrated by a dashed arrow in FIG. 1) reaches a terminal location gateway, denoted GMLC (for "Gateway Mobile Location Center") and part of the network. For example, the REQ request may be from a server of the police force or an authorized third party service by the operator, or other, to locate the terminal TER. The gateway GMLC can initially consult, for a rough location, the HLR register and deduce for example the identity of the central MSCl managing the base station BS21 serving TER terminal. Preferably, the gateway GMLC requests confirmation from the central MSC1 that the terminal TER is well served by the base station BS21, because the terminal TER, in a situation of mobility, can pass from one cell covered by the station BS21 to another cell network (so-called "handover situation").

In a first embodiment, each central MSC1, MSC2 manages its own correspondence table TAB_MSC1, TAB_MSC2, independently of the contents of the register HLR, therefore without synchronization. For this purpose, it is decided to assign different aliases for base stations managed by different central entities MSC1, MSC2. The GMLC gateway, by searching for the location of the terminal TER, receives from the register HLR the temporary identifier alias2 of the cell which covers the terminal and consults the central office MSC1 with this temporary cell identifier alias2 assigned to the station BS21. As illustrated in FIG. 2, the central office MSC1 finds in its table TAB_MSC1, starting from the temporary identifier alias2, and from there, from the immutable cell identifier ID_cell2_BSCl_MSCl, the location of this geoloc2 station, which is transmitted to the GMLC gateway in response to its request.

In a second embodiment, the central entities MSC1, MSC2 manage their correspondence table TAB_MSC1, TAB_MSC2, in synchronization with the holding of the register HLR. Thus, in this embodiment, the station identifier with which the gateway GMLC consults the central office MSCl is the temporary identifier alias2 assigned to the station BS21 serving the terminal TER, since the association information terminal TER is stored in correspondence of the temporary identifier alias2 in the register HLR that consults the gateway GMLC. As illustrated in FIG. 2, the central office MSC1 finds in its table TAB_MSC1, from the identifier "alias2", the immutable identifier ID_cell2_BSCl_MSCl initially assigned to the station BS21 and hence its location geoloc2, which is transmitted to the GMLC gateway in response to his request.

It is indicated here that if the central MSC1 does not manage base stations serving the terminal TER, this central can transfer the request of the gateway GMLC to other neighboring central entities MSC2.

It will be noted here that in the first or the second embodiment, the base station identifier may be the temporary alias or the immutable identifier in the exchanges between the central entities MSC1, MSC2, the HLR register manager and the GMLC gateway. For this purpose, it is advantageous to filter requests received from the GMLC gateway to respond only to authorized external entities (network operator itself, police forces, or other).

On the other hand, as regards the communications between the base stations, the base station controllers BSC and the central entities MSC, the apparent identifier of each base station remains rigorously the alias assigned by the central office MSC. Thus, it is never communicated to any base station identifier TER terminal other than the temporary alias assigned to this base station. The assignment of temporary aliases can be done for example by random draws, regularly among a plurality of possibilities offered to each central MSC. The draw may, in particular, be pseudo-random, that is to say, respecting a secret logic that only the operator of the network. Moreover, another possible formulation of the variability of temporary identifiers is that they can vary in time and / or space (or other), ie for example that an identifier can be assigned for a finite duration at a given access point while previously assigned to another access point.

Thus, it will be remembered that a network equipment, such as for example an MSC entity and / or an entity holding the HLR register, can make it possible to ensure that the correspondence between the cell identifier and the position of the cell is known only by elements of the network and never by the terminals. Once the aliases are changed and supplied to the base stations, the network elements in charge of this aliasing mechanism can ensure the synchronization of the other network equipment (eg service platforms like the AGPS for "Assisted GPS "). Thus, this equipment will always have systematically updated alias information.

Of course, the present invention is not limited to the embodiment described above by way of example; it extends to other variants.

For example, to make it more difficult for the network topology to be accessible to third parties, provision may also be made to use a temporary access point identifier that is different by terminal issuing a location request and covered by this point. access. In other words, new temporary identifiers would be allocated for each terminal location request, detected in the network.

In addition, a network entity such as an MSC exchange for the assignment of base station aliases has been described with reference to FIG. An equivalent variant consists in assigning this task to a node of the type network SGSN (for "Serving GPRS Support Node", with GPRS for "General Packet Radio Service") typically used for data communication in a network-oriented network.

Claims

A method for managing a wireless network, the network comprising at least one access point, the method comprising assigning to said at least one access point an identifier used for a communication with a terminal, characterized in that said at least one access point identifier is variable in time. 2. Method according to claim 1, characterized in that a variable identifier is unique. 3. Method according to claim 1, characterized in that it comprises a step of storing a correspondence table (TAB_MSC1) comprising at least one correspondence between an immutable identifier assigned to an access point, and a temporary identifier of said variable access point in time. 4. Equipment for a wireless network (MSC1, MSC2), in charge of managing at least one access point of the network, characterized in that it comprises means for assigning a variable identifier over time to a respective access point. 5. Computer program, characterized in that it comprises code instructions for the implementation of the method according to claim 1, when executed by a processor. 6. System in a wireless network, the network comprising at least one access point managed by at least one device, characterized in that at least one device comprises means for assigning a variable identifier over time to a point d respective access.