Telecommunications network and method for time-based network access

FIELD OF THE INVENTION

0001The invention relates to the field of telecommunications. In particular, the invention relates a telecommunications network and a method of permitting access to said telecommunications network.

BACKGROUND OF THE INVENTION

0002The past decades have seen an ever increasing demand for data capacity of telecommunications network. Telecommunications providers have adapted their networks to provide extended GSM services, like GPRS, and 3G services and are continuing to provide further services to meet the demands of their clients.

0003Telecommunications providers have made attempts to influence the behaviour of their clients in order to efficiently use network resources. As an example, mobile data subscriptions nowadays are usually offered using volume based billing, possibly in combination with a volume cap, thereby forcing clients to consider the amount of data to be transmitted over a network. However, the control of the client behaviour and/or terminal data transmission and, therefore, the use of the network resources is still limited.

0004There is a need in the art for an improved telecommunications network and method for regulating the use of network resources.

0005<patcit id="pcit0001" dnum="WO0155861A"><text>WO 01/55861</text></patcit> describes access to the internet by an individual via a computer terminal wherein access depends on a user profile which includes information regarding when or under what circumstances the user is allowed to access the internet. The user profile can include billing information, account information and an individual user grant access time to the internet.

0006<patcit id="pcit0002" dnum="EP1681815A"><text>EP 1681815</text></patcit> discloses a data communication restriction method for flat rate users. The data communication restrictions method comprises the steps of monitoring data communication status of a flat rate user and determining whether the number of request or communication quantity during a predetermined period exceeded a predetermined threshold ; setting the flat rate user as a communication restricted object when it is determined that the threshold was exceeded ; and transmitting a communication restriction signal including communication restriction period Information to a mobile terminal of the restricted flat rate user, when the restricted flat user requested access again ; whereby data communication of the mobile terminal of the restricted flat rate user is restricted during the communication restriction period.

SUMMARY OF THE INVENTION

0007A telecommunications network configured for providing communication access to a plurality of terminals is proposed in accordance with claims 1 and 13.

0008A computer-implemented method as defined in claims 15 and 24 of controlling access to a telecommunications network is also proposed.

0009A computer program and a carrier for such a computer program comprising program code portions configured for executing the method are also proposed.

0010It should be appreciated that an equivalent of the grant access time interval includes a deny access time interval identifying a time interval during which an access request for access to the telecommunications network is to be denied.

0011The access request may be a circuit-switched access request, a packet-switched access request or a combined request.

0012The steps of accessing a telecommunications network are standardized in e.g. 3 GPP TS 23.060 (Release 7). It should be appreciated that the access to the telecommunications network can be denied at various access phases. The first phase of requesting network access typically involves a network attach procedure comprising several steps. Preferably, access to the telecommunications network is denied by denying network attach of the terminal. Denying at this phase provides for optimized saving of resources.

0013A further network access phase involves the establishment of a PDP context. Establishment of the PDP context may be denied. Although the preceding network attach already involved the use of network resources, prohibiting the establishment of a PDP context prevents effective use of the telecommunications network and hence saves resources. It should be noted that operator determined barring (ODB) as such for access to a telecommunications network is already described in 3GPP TS 23.015, V. 7.0.0. The barring possibility allows network operators to deny access to particular destinations for certain subscribers.

0014By providing the option of specifying one or more time intervals during which access to the telecommunications network is allowed for a particular terminal or group of terminals, the network operator planning and control of the use of network resources is facilitated. Denying or blocking access during time intervals can prove advantageous in various situations. In particular, some machine-to-machine (M2M) applications do not require the transfer of data to be immediate. If these applications are prevented from claiming one or more network resources during e.g. peak load hours, network resources can be saved. Such subscriptions may e.g. be offered at a lower subscription rate.

0015M2M applications typically involve hundreds or thousands of devices that only rarely require access to a telecommunications network. An example involves the electronic reading of e.g. electricity meters at the homes of a large customer base.

0016There are aspects that provide for a suitable place in the telecommunications network for making available the combinations of terminal identifier(s) and associated time interval(s).

0017There are aspects that provide for a dynamic time interval (and possibly a virtual or implicit time interval) during which access to the telecommunications network is allowed/prohibited. These embodiments contribute to the optimum use of network resources.

0018There are aspects that provide for an improved use of network resources.

0019There are aspects that provide the option to inform the terminal of the grant access time interval. Such information should only be transmitted to the terminal in question. Moreover, only allowing single authentication saves network resources and saves power for the terminals.

0020There are aspects that ensure that the decision whether or not to allow access (either network attach or establishment of the PDP context) to the telecommunications network is embedded at a low level of the telecommunications network, e.g. at the SGSN, reducing network resource consumption. Other solutions, such as the implementation of grant access time rules in a RADIUS server, would require several network functions, mobility management and setting up a packet data protocol (PDP) context, and, thereby, unnecessarily consume network resources in case it would be determined that the terminal accessed the telecommunications network outside the grant access time interval.

0021There are aspects that allow the transmission of information to the terminal. Such information may include information concerning the applicable grant access time interval. Possibly, the information may include control information for controlling terminal operation. The control information may e.g. control the terminal to log in during a time interval wherein the network load is expected to be low. An authentication procedure is preferably performed for this terminal.

0022There are aspects that provide for higher level authentication, e.g. at a GGSN, during the grant access time interval.

0023Hereinafter, aspects of the invention will be described in further detail. It should be appreciated, however, that these embodiments may not be construed as limiting the scope of protection for the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

0024In the drawings: <ul id="ul0001" list-style="none" compact="compact"><li><figref idref="f0001">FIG. 1</figref> shows a schematic illustration of a telecommunications network according to an embodiment of the present invention;</li><li><figref idref="f0002">FIG. 2</figref> shows a HLR, a SGSN and a GGSN of the telecommunications network of <figref idref="f0001">FIG. 1</figref>;</li><li><figref idref="f0003 f0004 f0005 f0006">FIGS. 3A-3D</figref> show various time diagrams of methods for using the telecommunications system of <figref idref="f0001">FIG. 1</figref>; and</li><li><figref idref="f0006">FIG. 4</figref> shows a schematic illustration of a terminal for use with the telecommunications network of <figref idref="f0001">FIG. 1</figref>.</li></ul>

DETAILED DESCRIPTION OF THE DRAWINGS

0025<figref idref="f0001">FIG. 1</figref> shows a schematic illustration of a packet service telecommunications network 1 in combination with a plurality of terminals A-D that may access the telecommunications network 1 for data communication.

0026The telecommunications network 1 comprises a radio access network 2 containing a base transceiver station 3 and a base station controller 4. The radio access network is connected to a mobile core network containing a serving controller entity

0027The serving controller entity 5 may be a serving GPRS support node (SGSN) or another entity. The SGSN 5 controls the connection between the telecommunications network 1 and the terminals A-D. It should be appreciated that the telecommunications network may contain a plurality of SGSNs, wherein each of the SGSNs is connected typically to base station controllers 3 in such a way that they can provide a packet service for terminals via several base stations 3.

0028The register 6 may be a home location register (HLR) or another register (such as a home subscriber server for IMS).

0029The gateway 7 may be a GPRS gateway support node (GGSN) to e.g. the internet. Other external networks include a corporate network or another network of the operator. The GGSN 7 is connected to the SGSN 5 via a core network.

0030Access for the terminals A-D to the telecommunications network 1 involves a number of access phases.

0031The first phase involves the phase during which a terminal A-D performs an attach to the telecommunications network 1. In this phase, various communication steps are performed, including authentication steps, as exemplified in 3GPP TS 23.060 (Release 7). The authentication steps perform a security function and involve exchange of an authentication triplet (for GPRS) or quintet (for UMTS).

0032In a subsequent phase, a packet data protocol (PDP) context may be established to carry traffic flows over the telecommunications network 1. A PDP context typically includes a radio access bearer provided between a terminal A and the SGSN 5 and switched packet data channels or tunnels provided between the SGSN 5 and the GGSN 7. A session between the terminal A and another party would then be carried on the established PDP context. A PDP context can carry more than one traffic flow, but all traffic flows within one particular PDP context are treated the same way as regards their transmission across the telecommunications network 1.

0033In operation, the terminal A may indicate after the network attach phase, in a message requesting to activate the PDP context in the network, an access point name (APN) for selection of a reference point to a certain external network 8. The SGSN 5 may send a PDP context creation request to the GGSN 7 selected e.g. according to the access point name given by the terminal A or to a default GGSN known by the SGSN 5. Subsequently, the PDP context is activated by allocating a PDP context data structure in the SGSN 5 that is used by the terminal A and the GGSN 7 serving the subscribers access point. The data structure contains an IP address of the terminal A, the IMSI of the terminal A and tunnel ID's at both the SGSN 5 and the GGSN 7. The tunnel ID is a number allocated by the GGSN 7 which identifies the data related to a particular PDP context.

0034Various features can be controlled by the SGSN 5 during a communication session. This control may be based on information associated with the subscription and stored in the HLR 6. The information may be retrieved from the HLR 6 to the SGSN 5 to allow control at the SGSN-level.

0035In particular, and with reference now to <figref idref="f0002">FIG. 2</figref>, the HLR 6 contains a unique identifier associated with the subscription for each terminal A-D, e.g. the IMSI stored in the SIM of the terminal A-D. Each terminal A-D has been assigned a time interval during which access to the telecommunications network 1 will be granted.

0036In this example, for terminals A and B, access will be granted between 0800-1100pm. For terminal C, access will be granted between 0000-0500am. These time intervals are typically off-peak intervals for most days of the year. Batches of terminals may be defined and assigned a particular interval of the off-peak hours. For terminal D, a variable time interval x-y is scheduled, depending on the network load experienced by or expected for the telecommunications network 1. If the network load drops below or is expected to drop below a particular threshold, access is granted to the terminal D.

0037Of course, the time intervals may also relate to time slots during which access to the telecommunications network 1 is denied, i.e. access deny time intervals. Multiple time intervals may be assigned to a terminal.

0038In order to control the use of resources of the telecommunications network 1, the SGSN 5 contains several modules for performing the operations described below in further detail. It should be noted that one or more of these modules may be implemented as software modules running on a processor (not shown). The SGSN 5 further contains memory and storage (not shown) for performing these operations in a manner generally known to the skilled person.

0039The SGSN 5 comprises an access request receiver 20 configured for receiving an access request from the terminals A-D for access to the telecommunications network 1. The access request of a terminal contains the IMSI of the SIM available in this terminal.

0040The SGSN 5 has an access module 21 configured for denying access for a terminal to the telecommunications network 1 if the access request is received outside the grant access time interval(s) for that terminal (or within the access deny interval). The access denial may relate to the network attach or the establishment of the PDP context.

0041Moreover, the SGSN 5 comprises a data retrieval module 22. The data retrieval module 22 is configured for retrieving data from the HLR 6, in particular the applicable access grant time interval associated with the terminals A-D from which the access request was received. However, it should be appreciated that the SGSN 5 itself may be pre-configured with respect to particular terminals and therefore already comprise the grant access time interval(s) for these terminals. This may be particularly advantageous for stationary terminals.

0042The SGSN 5 also comprises a PDP context establishing module 23 and an authenticator 24.

0043SGSN 5 may also have a network load monitor 25 configured for monitoring the network load of the telecommunications network 1. Network load information may also be obtained from other sources, e.g. other SGSNs or the HLR of the telecommunications network 1. Network monitoring may be real time and/or be based on the expected network load using mathematical models and history data to obtain an appropriate load expectation.

0044The operation of the telecommunications network 1, and in particular the SGSN 5, will now be described with reference to <figref idref="f0003 f0004 f0005 f0006">FIGS. 3A-3D</figref>.

0045In <figref idref="f0003">FIG. 3A</figref>, the access request receiver 20 of the SGSN 5 receives an attach request from terminal A at 0700pm in step 30. To be able to process this attach request, the SGSN needs the IMSI of the SIM available in the terminal. The attach request may contain either this IMSI or a P-TMSI assigned to terminal A by an SGSN. The P-TMSI is used to prevent transmission of the IMSI over the radio path as much as possible for security reasons. If the P-TMSI provided by terminal A is known in the SGSN, the SGSN is able to derive the IMSI. Alternatively, for a P-TMSI provided by terminal A that is not known by the (new) SGSN, the IMSI is provided either by the old SGSN or the terminal itself on request of the new SGSN. The IMSI is used by data retrieval module 22 to retrieve the grant access time interval (0800-1100pm) from the HLR 6 to the SGSN 5 in step 31.

0046The grant access time interval may be communicated from the HLR 6 to the SGSN 5 in a variety of ways.

0047The attach request 30 is typically followed by an authentication check, step 31. The grant access time interval may be transmitted to the SGSN 5 with the authentication triplet or quintet.

0048The authentication procedure of the network attach phase is typically followed by a location update procedure. First an update location request 32 is transmitted from the SGSN 5 to the HLR 6. The grant access time interval may also be transmitted to the SGSN 5 in a subsequent Insert Subscriber Data message from HLR 6 (step 33). The network attach phase is finalized with an attach accept message to the terminal A (step 34).

0049After finalizing the network attach phase (which may comprise further steps than mentioned in the previous paragraphs), a PDP context is established. The terminal A requests establishment of the PDP context in an activate PDP context request 35.

0050Irrespective of the manner of obtaining the grant access time interval, the access module of SGSN 5 determines that the access request was received outside the grant access time interval. Consequently, a PDP context is not established (indicated by the cross in step 36). The terminal A is informed of the denial in step 37.

0051It is noted that the authenticator 24 of SGSN 5 may or may not have authenticated terminal A in the above situation. Authentication is required if the grant access time interval is transmitted from the HLR 6 to SGSN 5 in response to the update location message 32. However, authentication should not be completed if the grant access time interval is obtained in SGSN 5 with the authentication triplet/quintet. Authentication is preferred if the denial message 37 to the terminal A contains information concerning the grant access time interval.

0052The SGSN 5 comprises or obtains and maintains the data of the failed access request. This may e.g. be done by storing the time interval in combination with the IMSI of terminal A or by flagging the terminal A temporarily in combination with some time indication.

0053Another access request at a time outside the window 0800-1100pm (step 38), again containing or followed by the IMSI of terminal A, may then be denied directly (step 39). Authentication will not be performed again.

0054In <figref idref="f0004">FIG. 3B</figref>, the network attach of terminal A is received at 0900pm. Steps 40-45 correspond to steps 30-35. Since the network attach request is now within the time interval allocated for access for the terminal A, access module 21 controls the PDP context establishing module 23 of the SGSN 5 to establish a PDP context with the terminal A and to establish a PDP tunnel with the GGSN 7. In particular, step 46 involves a Create PDP Context Request and step 47 a Create PDP Context Response in a manner known as such. In step 48, the terminal A is informed by a Activate PDP Context Accept message. The terminal A may now follow another authentication procedure (step 49), using e.g. a RADIUS server in the further network 8.

0055The network load monitoring module 25 of SGSN 5 may monitor the network load of (a part of) the telecommunications network 1 or output an expected network load. The network load may be compared with a load threshold in order to evaluate the existence of a low network load situation at a particular time or time interval.

0056In <figref idref="f0005">FIG. 3C</figref>, steps 50-53 correspond to steps 30-33 of <figref idref="f0003">FIG. 3A</figref>. Authentication of terminal D is performed and in step 54, the terminal D is informed of a time interval x-y during which a low network load is expected. The information includes control information to control terminal D such that it accesses the telecommunications network 1 again (step 55) in such a low network load time interval. A PDP context can be set up immediately (steps 56-58) and access to the RADIUS server is allowed.

0057As mentioned above, the denial of access to the telecommunications network 1 is preferably performed during the network attach. <figref idref="f0006">FIG. 3D</figref> shows in step 60 a network attach message of terminal A containing an IMSI. Then an authentication procedure is performed (step 61) during which the grant access time interval is received at SGSN 5. The grant access time interval and the IMSI is stored at SGSN 5. Alternatively, the grant access time interval is obtained in the location update procedure (steps 62 and 63). The network attach is denied in step 64.

0058As mentioned before, SGSN 5 may itself comprise pre-configured information regarding the grant access time interval for terminal A. Alternatively, the SGSN uses authenticator 24 to authenticate terminal A and to provide terminal A with information regarding the grant access time interval in step 61.

0059<figref idref="f0006">FIG. 4</figref> shows a schematic illustration of terminal A. The terminal A comprises a transceiver module 70 for communicating with the telecommunications network 1. The terminal A further has an access request module 71. The access request module is configured for receiving information regarding the grant access time interval from the telecommunications network 1 via the transceiver module 70 and to transmit an access request to the telecommunications network only at a time within the grant access time interval.

0060It should be noted that the above described telecommunications network and system are especially suitable for saving resources. There may be other approaches to influence access behaviour of terminals but these are considered to waste more resources.

0061As an example, a network provider may allow access to the network at all times but charge a (very) high rate for data sent outside the off-peak time. This provides no incentive for the user to tear down the connection (i.e. the PDP context) to the network. It only provides an incentive to not send data during the expensive peak hour. However, an active PDP context still consumes a lot of resources in the mobile radio and core network as well as requiring an IP address. It also requires the terminal being attached to the network, meaning all kinds of mobility management features should be in place. Furthermore, this solution requires a more complicated billing system that allows charging higher rates at certain times.

0062Another example would include blocking access to the terminal during peak hours as a rule in a RADIUS server. However, network resources would already be consumed before access is blocked by the RADIUS server. The terminal is already allowed to attach to the network, meaning the SGSN would have retrieved information from the HLR, and is performing mobility management functions. Also, the terminal has been allowed to establish a PDP context. If the RADIUS server would reject the request for access to the external data network, the GGSN would not accept the PDP context, and the tunnel would be taken down. Attachment to the network will however continue if no additional measures were taken.