Method and apparatuses for providing local traffic in a cell or group of cells of a cellular communication network

ES 2 385 751 Al

DESCRIPTION

PROVIDE LOCAL TRAFFIC IN A CELL OR GROUP OF CELLS OF A CELLULAR COMMUNICATION NETWORK

BACKGROUND OF THE INVENTION

Technical field

The present invention relates to cellular telecommunications networks and in particular to cellular telecommunications networks in which local traffic (calls and / or messages) can be provided between users in a cell area or group of cell areas.

Description of Related Art

Cellular network operators are developing their networks in increasingly remote areas. Consequently, the instability in the transmission links, which are part of the radio access network, that is, the base station system (BSS, Base Station System) in the case of 2G networks or the radio access network (RAN, Radio Access Network) in case of 3G networks, it is becoming a common problem. In emerging markets, this instability is typically due to more challenging requirements on network links, such as distance, terrain, improper maintenance, poor quality transport networks, etc. Due to this instability, users suffer frequent service outages. This weakens customer confidence in the service and has an economic impact, both for users and operators. Thus, it would be desirable to provide a solution that can alleviate transmission problems and provide service with an acceptable level of quality in remote areas.

There have been several attempts to minimize the transmission bandwidth used in the cellular communication network for isolated / rural coverage and to address the impact of instability on transmission links. Two approaches can be distinguished.

The first approach, referred to as "local switching" is a network link functionality that allows the flow of traffic information to be switched at the user plane through the access node (BTS, Base Transceiver Station) when establishes a call between parties that are in the same BTS coverage (see 3GPP working document CP-090812, version # 10). Information

ES 2 385 751 The control plane al (ie signaling) is still directed towards other access nodes: the base station controller (BSC, Baste Station Controller) and the core network (CN, Core Network). Thanks to this functionality, some savings are obtained in transmission bandwidth links. An example of how this local switching works is illustrated in Figure 1: a 2G cellular communication network 10 comprises access nodes 20 (BTS), radio control nodes 30 (BSC) and a core network 40. Voice calls 60 between mobile users 50 in the same cell area covered by one of the access nodes or in the cell areas of a grouping of access nodes, are switched locally. However, signaling 70 proceeds to core network 40.

This obviously results in a considerable reduction of the transmission bandwidth used in the radio access network, because the round-trip voice transmission connection from the access node 20 to the core network 40 can be dispensed with. , this solution has no impact on the value added services or VAS (value added services) provided by the cellular communication network. They can be provided in a conventional way by the core network, because signaling messages from and to the mobile station involved in the voice call within the BTS are at your disposal. Finally, a fundamental change in the architecture of the cellular network is not necessary.

However, a transmission link failure in the access network results in a complete stop of service because signaling can no longer reach the core network. Furthermore, local business models are not possible in which the billing and provision of calls of the users 50 are managed locally.

The second approach, referred to as "network in a box", provides a local system that is designed to provide an emergency or temporary network to provide coverage after a disaster. This solution includes a functional preconfigured core network that offers radio access network routing, authentication and management. Node B options and expansion kits allow customers to create a custom network that meets their needs.

Figure 2 schematically illustrates certain features of an implementation of this second approach. In this case, the radio control node functionality 30 'and the core network functionality 40' are disabled for an access node 20 or access node cluster. Voice calls 60 between local mobile users 50 in the same cell area covered by one of the access nodes or in the cell areas of a grouping of access nodes, are switched and controlled locally, via a local network 80 covering the cell areas of the node

ES 2 385 751 To access 20 or grouping of access nodes. Local users are manually provisioned on local network 80.

In this second approach there is no integration with any operator network of any kind, since this system provides a solution designed to provide an emergency or temporary network. In fact, only provisioned users on the system can make calls.

SUMMARY OF THE INVENTION

It is an object of the invention to provide a network component and a method for locally emulating a core network for use in a cellular communication network by which the aforementioned problems are at least partially solved.

In this regard, according to the invention a network component and a method are provided according to the independent claims. Preferred embodiments are defined in the dependent claims.

The invention provides a computer or laptop program that locally emulates the functionality of a radio controller / mobile switching center or MSC (Mobile Switching Center), connected to a base station BTS. It is also possible that the program or software is integrated into the BTS.

According to one aspect of the invention, a network component of a cellular network is provided, the cellular network comprising:

- a plurality of access nodes each covering a cell area;

- an access control node common to all access nodes to control the provision of traffic;

wherein the network component comprises:

- a classifier for initially classifying users of the cellular network into a group of local users and a group of public users, wherein said group of local users includes users in a cell area or areas covered by a single access node or group of access nodes; Y

- a communication manager for:

- check if a call or SMS is established by a user belonging to the local user group or the public user group;

- control the provision of calls and / or SMS established between users belonging to the local user group;

- pass control to the access control node of the calls and / or SMS

ES 2 385 751 To the remainder, the network component being arranged in communication with said single access node or group of access nodes.

Thus, according to the invention the users are divided into a first group of local users, for which the provision of traffic communication is controlled locally by means of the network component provided by the invention, and a second group of public users for the that the provision of traffic communication is centrally controlled by a core functionality, including an access control node and a core network. As a result, public users are not managed as roaming when they are in the cell area or areas covered by the single access node or group of access nodes, which area is referred to herein as the local coverage area. Furthermore, since the provision of calls for public users is centrally controlled in the cellular communication network there is no restriction of VAS value-added services for public users. Users belonging to the local user group can also benefit from the VAS services provided by the cellular communication network.

The network component according to the invention can also communicate and synchronize with the main network of the public cellular communication network, so that as long as the link between the network component and the public cellular network is available and operational, the local users also can benefit from VAS services. Finally, local traffic does not require a transmission link to a radio control node or core network of the cellular communication network, so that no transmission link failure affects local traffic.

Preferably, the network component further includes monitoring means for detecting a stop in a link between at least one of the access nodes and the access control node, in which case the communication manager is further configured to allow traffic between all users located in that area or cell areas covered by the single access node or group of access nodes, regardless of whether they are local or public users. Consequently, the service in the local area is not interrupted in the event of a link stop on the link to the public cellular network.

According to an embodiment of the invention, the network component is implemented as a conventional computer on which a computer program is executed, the computer being arranged locally with respect to the access node or group of access nodes. In this way, it increases but does not replace the hardware (BTS / node-B and BSC / RNC) and

ES 2 385 751 To existing software. No new elements or modifications to the network architecture are required apart from a conventional computer (eg laptop) and the corresponding software package.

Preferably, the network component is configured to bill local users and the core functionality is configured to bill public users. In this way, local business models are made possible, in which a local network operator offers communication services to local users in the coverage area of ​​a single access node or a grouping of access nodes.

According to a further embodiment of the invention, the functionality implemented by the network component is transparent to public users. In this way, the service to public users in the local coverage area is not different from the service in other coverage areas of the cellular communication network and public users will not notice any difference.

According to another embodiment of the invention, a local user becomes a public user outside the cell area of ​​his access node or group of access nodes. In this way, local users are provided with non-roaming communication services in the coverage area of ​​the entire cellular communication network and not just in the local area.

The core functionality can be implemented by a conventional access control node (BSC / RNC) and core network of the cellular communication network (MSC).

According to yet another embodiment of the invention, the traffic between public users in the cell area or areas covered by a single access node or group of access nodes is switched locally. As a consequence, only the signaling of the public users in the local coverage area is transmitted to the core functionality of the cellular communication network and not the traffic. This results in a further reduction in the use of transmission bandwidth on the links between the access node (s) and the rest of the cellular communication network.

According to another aspect of the invention, a method is provided for locally emulating a core network in a cellular communication network comprising a plurality of access nodes each covering a cell area and an access control node common to all access nodes to control the provision of traffic; the procedure comprising the stages of:

- carry out an initial classification of users of the cellular network into a group of local users and a group of public users, in which said group of

ES 2 385 751 Al local users includes users in a cell area or areas covered by a single access node or group of access nodes; Y

- check whether a call or SMS that is established by a user belonging to the local user group or the public user group;

- control the provision of calls and / or SMS established between users belonging to the local user group;

- pass control to the access control node of the remaining calls and / or SMS. In a preferred embodiment, the method comprises the additional step of:

- detect a stop in a link between at least one of the access nodes and the access control node, and

- enable traffic between all users located in that area or cell areas covered by the single access node or group of access nodes.

Preferably, the method according to the invention is implemented by means of a computer program loaded into a network component of the cellular communication network.

These and other aspects of the invention will be apparent from and clarified with reference to the embodiments described hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood and its various objects and advantages will become more apparent to those skilled in the art by reference to the following drawings, in conjunction with the accompanying specification, in which:

Figure 1 shows a first approach to providing local traffic in a cellular communication network according to the prior art.

Figure 2 shows a second approach to providing local traffic in a cellular communication network according to the prior art.

Figure 3 shows the approach to providing local traffic and non-local traffic in a cellular communication network according to an embodiment of the present invention.

Figure 4 shows a flow chart describing the call / SMS handling procedure according to the present invention.

Throughout the figures identical reference numerals refer to identical elements.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

Referring now to Figure 3, an embodiment of the invention is described. The

ES 2 385 751 The embodiment is described with reference to a 2G cellular communication network and related voice calls and SMS messages. However, it should be understood that the person skilled in the art can also implement the present invention for other types of technologies, for example in 3G cellular communication networks without any undue burden.

A 2G cellular communication network 10 is shown, which, as usual, comprises a plurality of radio access nodes 20 (BTS), one or more access control nodes (BSC) 30 (only one BSC is shown, for greater clarity) and a core network 40 or in English, “core network”. The main network comprises the conventional network nodes and functionality of a 2G cellular communication network, such as the MSC mobile switching center, HLR (Home Location Registe /) local location register, Visitor Location Registe / VLR (visitor location register). ), SMSC (Short Message Service Centei) short message service center, billing function, OSS (Operations Support System), etc. The functionality of the BSC 30 and the core network 40 together are referred to as "core functionality" in this description. For one of the BTS 20 or a group of BTS covering a specific local area, the functionality of the control node 30 and the most relevant functionalities of the core network, as listed, are implemented locally by means of software run on a conventional computer 100 (for example, a laptop) connected to the BTS (s) 20. This functionality is referred to as "local functionality" in this description. So this conventional computer 100 condenses part of the functionalities traditionally supported by the BSC 30 and the core network 40. Alternatively, the local functionality can be integrated into the BTS itself.

According to the invention, users are classified either as "local users" 110 or as "public users" 120. Local users are supplied by local functionality and public users are supplied by central functionality.

In the case of having a single BTS 20, the computer can physically connect directly to the BTS 20 via, for example, an Ethernet link. And the BTS to the control node 30. In case of having a group or grouping of BTS 20, the connection will depend on how the BTS are interconnected; most likely, the BTS links are concentrated in one router or "router", and the computer also connects to this router. And from the router there is a link to the control node.

A preferred embodiment to control the BTS / Node B uses the common public radio interface CPRI (Common Public Radio Interface), which is a specification of the

ES 2 385 751 To the industry that standardizes the control functions for the radio base station in lower layers (layers 1 and 2 of the GSM OSI stack), and that enables the computer to make the BTS act according to what is defined in the invention. On top of this, the computer implements proprietary software that translates the actions for the BTS into CPRI commands. For example, in case of a call between two local users and in the case of activated link:

• During call establishment, both mobiles report their IMEI.

• These IMEIS are captured by the computer confirming that both users are local.

• Thereafter, the computer informs the corresponding BTS through CPRI instructions that it takes care of how the call proceeds for this particular call.

For the purpose of interaction with the rest of the network elements (BSC, core network), the computer reuses the existing link between the BTS 20 or the group of BTS and the BSC 30; and thus, it could use the O&M link normally configured on Abis (2G) or lub (3G) interfaces.

The control of the call provision and the billing of local users is carried out by the local functionality, provided that the users are in the area, which is the area covered by the access node or group of access nodes in which it is implemented. local functionality. When a local user leaves their local area, they become a public user.

Local functionality follows applicable 3GPP standards (eg TS 44.XXX 3GPP specification series, signaling protocols) to control call provisioning for local users.

The central functionality controls the provision of calls and the billing of public users; In other words, this control and billing is performed by the control node 30 and the core network 40 in a conventional manner.

To differentiate between local users and public users, IMSI numbers can be assigned from different ranges and / or different sets of numbers.

Regarding security aspects, the local functionality supports standardized 3GPP encryption algorithms common on the radio interface (eg A5 / 1, A5 / 3, etc.). In the event that legal interception is necessary, if the link between the local and central functionalities is available and operational, the central functionality will assume this responsibility, regardless of the type of user. In the event of lawful interception of a local user, the local functionality will receive an order to

ES 2 385 751 To the interception of a particular local user from the central functionality and will route all calls belonging to that local user through the central functionality. If there is a link stop between the local and central functionalities, the local functionality implements capabilities to record and store all calls that involve intercepted users; and when the link is operational again, it will provide this information to the operator.

Although the local functionality may implement some operation / configuration capabilities to change some parameters in the BTS or group of BTS, the main operational responsibilities will belong to the core functionality (eg OSS).

As shown in Figure 4, once the BTS 20 receives a call establishment request or SMS between User A and User B (step 1001), the local functionality checks (step 1002) if the link between the functionalities local and central is available and operational. If this link does not work - due, for example, to some stop - (1002n), it is checked (1003) if both users A and B are in the local area (area covered by the BTS or group of BTS that directly implement the invention or to which computer 100 is connected). If so (1003y), the local functionality handles the call / SMS (1007), regardless of whether the users are public or local users. Unless both users are in the local area (1003n), the call / SMS cannot be handled (1008).

If the link between the local and central functionalities is available and operational (1002y) and if both users A and B are defined as local users and are provisioned by the local functionality (1004y and 1005y), the local functionality handles the call (1007) . If not, if any of the users is a public user (1004n; or 1004y and 1005n) the central functionality handles the call / SMS (1006).

In this way the local functionality monitors outgoing signaling messages originating from mobile users in the local coverage area. It filters out signaling messages from local users for local processing and passes the rest to control node 30. Consequently, local functionality is transparent to public users.

In case of intercepting signaling originating from a local user 110 to establish a call or SMS, originating from a local user, the local functionality takes care of the control and billing of the call / SMS originated by the local user. First of all, it is determined if the destination of the traffic is also a local user in the local area of ​​the access node or group of access nodes by consulting the HLR

ES 2 385 751 Al implemented by local functionality. If the destination is also a local user located in the local coverage area, this means that the generated traffic will be local traffic, that is, traffic between users in the area or cell areas covered by the access node or group of nodes of local access. In this case the local functionality executes a signaling procedure 60 with both local users. This results in a locally switched SMS / call 70 between them.

In the event that a public user 120 establishes a call, the local functionality will transparently pass the corresponding signaling to the network control node 30. Although the destination of the call is another public user, which is also located in the local area, the signaling 130 is routed to and from the control node 30 and the "central functionality" will execute the call control and billing in a conventional manner. However, the call 140 itself can be switched locally in the manner described with reference to the prior art solution shown in the figure.

1. Since local switching is a widely known standard functionality, it does not need to be described in more detail here.

In case a local user 110 calls a public user 120 located outside the local user's local area, the central functionality will execute both the signaling and the call in a conventional way, as shown in the figure by a double arrow 150. The Local functionality implemented by computer 100 is only involved in local user billing.

In the event that a public user 120 calls a public user 120 located in a different local area, the central functionality will execute both the signaling and the call in a conventional manner, as shown in the figure by the double arrow 160.

In the event of a link outage between the local and central functionalities, the local functionality still enables processing of voice calls and SMS messages between all users located in the local area, regardless of whether they are local or public, providing additional robustness in comparison. with the prior art "local switching" functionality shown in Figure 1.

During the takeover after a link shutdown between the local and central functionalities, calls between local users are not affected. However, calls involving public users are likely to be dropped. During this process, all users in the local coverage area are informed by SMS about the type of services that are available during the stop. In addition, users can also be informed when the link is operational again.

ES 2 385 751 Al

Also, when there is a link outage, the local functionality takes over all the operations of the local network. Any information or changes collected during that time is subsequently synchronized with the central functionality, when the link is operational again.

When a local user leaves their local coverage area, they become a public user. In this regard, the user's IMSI is stored in both the HLR of the local functionality and the HLR of the central functionality. Additionally, the visitor location record (VLR) of the central functionality can also have local user data thanks to a prior synchronization process between the local functionality and the central functionality.

Thus, when a local user is outside his local area, the cellular communication network will conventionally handle traffic control and billing.

Although the invention has been illustrated and described in detail in the drawings and description above, such illustration and description are to be considered illustrative or exemplary and not restrictive; the invention is not limited to the described embodiments.

Although the invention has been described with reference to a 2G cellular communication network for voice calls and SMS messaging, it can of course also be implemented in 3G cellular communication networks.

Other variations to the disclosed embodiments may be understood and carried out by those skilled in the art practicing the claimed invention, from a study of the drawings, the specification, and the appended claims. In the claims, the expression "comprises" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. A single processor or other unit can fulfill the functions of several elements mentioned in the claims. The mere fact that certain measures are cited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. A computer program may be stored / distributed on a suitable medium, such as optical storage medium or solid state medium supplied together with or as part of other hardware, although it may also be distributed in other ways, such as via the Internet or other wired or wireless telecommunication systems. No reference numbers in the claims should be construed as limiting the scope.