WO2013030774A1

WO2013030774A1 - Method, apparatus and system for detaching and triggering user equipment

Info

Publication number: WO2013030774A1
Application number: PCT/IB2012/054441
Authority: WO
Inventors: Hannu Hietalahti; Matti Jokimies
Original assignee: Renesas Mobile Corporation
Priority date: 2011-08-31
Filing date: 2012-08-29
Publication date: 2013-03-07

Abstract

An arrangement is disclosed for triggering a user equipment that is not connected to a network. In machine type communications, there is a need for reducing network activity. However, at the same time there is a need to be able to wake up a device. In the disclosed arrangement, the network detaches the user equipment locally (12) and the user equipment is then triggered (13-16) when needed.

Description

METHOD, APPARATUS AND SYSTEM FOR

DETACHING AND TRIGGERING USER EQUIPMENT

Cross Reference to Related Application

This application claims benefit under 35 U.S.C. § 119(a) and 37 CFR 1.55 to UK patent application no. 1114986.1, filed on August 31, 2011, the entire content of which is hereby incorporated by reference.

This application also claims the benefit of US provisional patent application no. 13/222,320, filed on August 31, 2011, the entire content of which is hereby incorporated by reference.

Technical Field

The present invention relates generally to machine to machine communications. In embodiments, the present invention relates to a method, apparatus and system for detaching and triggering user equipment.

Background

Machine-to -machine communications (M2M communications) refers to technologies wherein devices can communicate with each other. The advancement in technology has introduced a large number of different applications wherein machine- to-machine communications (hereinafter also called machine type communications or MTC) may be used.

Because of the wide variety of different kinds of devices, standardisation in the field of machine type communications has been initiated in order to provide efficient communications. A known problem arises due to the potentially large number of MTC UEs (user equipment); the number of MTC UEs may eventually be much higher than the number of the ordinary terminals. To cope with a large number of UEs in the network, the resources reserved for the MTC UEs in the network, and the signalling generated by them, need to be minimised. Proposals for the above mentioned problem have been discussed. One proposal is to detach the UEs from the network. That is, the UEs are forced to an offline state. However, these UEs still need to be triggered, even though they are not reachable by ordinary paging mechanisms. Therefore, a specific trigger of offline user equipment needs to be applied. The introduction of new features in 3GPP (Third Generation Partnership Project) specifications impacting UEs is typically time- consuming. Therefore, the modifications should preferably be such that only the network elements need to be upgraded. Alternatively, the modifications should be based on the existing 3GPP specifications. One such alternative is to use CBS (Cell Broadcast System), so that the detached UEs receive the broadcast messages, which are transparent to a 3 GPP specified network. These messages can contain trigger commands. A drawback of this solution is that in order to implement it in LTE (Long Term Evolution) devices, modifications are required to LTE device specifications because CBS is not supported in LTE. Another theoretical solution is to use MBMS (Multimedia Broadcast Multicast Services). These services may be implemented in the user equipment. However, implementing MBMS or CBS are not preferable in low cost machine type communication user equipment and in any event, to activate an MBMS context, the user equipment must be registered to the network.

Summary

According to a first aspect of the present invention, there is provided a method for detaching and triggering a user equipment, the method comprising: attaching a user equipment to a telecommunication network; preventing expiration of a periodic location registration timer; detaching said user equipment from said network locally by said network with no signalling between the user equipment and the network; and triggering said user equipment, wherein the triggering comprises: submitting a trigger from a machine type communications server to said network; accepting said trigger in said network; and submitting a paging message from said network to said user equipment, wherein said paging message comprises identification information for providing the paging message to the user equipment. According to a second aspect of the present invention, there is provided apparatus for detaching and triggering a user equipment, the apparatus comprising a wireless telecommunication module for communicating, a memory for storing program code and a processor for executing program code, wherein the apparatus is configured to: attach a user equipment to a telecommunication network; prevent expiration of a periodic location registration timer; detach said user equipment from said network locally with no signalling between the user equipment and the network; and trigger said user equipment, wherein said apparatus is in the triggering process configured to: receive a trigger submitted from a machine type communications server to said network; accept said trigger in said network; and submit a paging message from said network to said user equipment, wherein said paging message comprises identification information for providing the paging message to the user equipment.

According to a third aspect of the present invention, there is provided a system for detaching and triggering a user equipment, the system comprising: at least one user equipment; at least one machine type communications server; and at least one network element; wherein the system is configured to: attach a user equipment to a telecommunication network; prevent expiration of a periodic location registration timer of the user equipment; detach said user equipment from said network locally by said network with no signalling between the user equipment and the network; and trigger said user equipment, wherein said network element is in the triggering process configured to: receive a trigger submitted from a machine type communications server to said network; accept said trigger in said network; and submit a paging message from said network to said user equipment, wherein said paging message comprises identification information for providing the paging message to the user equipment.

Embodiments of the invention provide an arrangement for detaching the UE from the network, and triggering the user equipment. In machine type communications there is a need for reducing network activity. This can be done by detaching the UE from the network. However, at the same time there is a need for being able to trigger, or wake up, a device. In embodiments, the user equipment is detached from the network locally by the network and then triggered when needed. The network resources can be minimised and the implementation overhead kept to a minimum.

In an embodiment, a user equipment is first attached to a telecommunication network. Next, when the network determines that the UE is an MTC UE, the UE is detached from the network. However, in contrast to the ordinary prior art detachment, there is no signalling between the network and the UE on the detachment. As consequence, the UE remains pageable as if it were attached to the network. Hence, the UE continues to receive also the paging messages as in the ordinary attached state.

To avoid that the UE tries to make periodic location updates, the expiration of a periodic location registration timer needs to be prevented in the UE. This may be done in embodiments by using existing signalling.

In an embodiment, triggering said user equipment comprises submitting a trigger from a machine type communications server to said network, accepting said trigger in said network and submitting a paging message from said network to said user equipment, wherein said paging message comprises identification information identifying the user equipment in a manner that the paging message can be submitted. The identification information may be, for example, the subscriber identification (such as an IMSI (International Mobile Subscriber Identity) code) or the user equipment identification (such as an IMEI (International Mobile Equipment Identity) code). More generally, the identification information may be any unique identifier corresponding to the locally detached UE. Another specific example is an Internet Protocol address, including for example an IPv6 address. Because the trigger message is targeted to a detached UE, an ordinary network implementation would reject the triggering request. However, in this embodiment, the network accepts the triggering request, and initiates the paging procedure. In an embodiment, preventing the expiration of a periodic location registration timer comprises setting a very long expiration time. In an embodiment, preventing said expiration of a periodic location registration timer comprises disabling said periodic location registration timer. In an embodiment, preventing said expiration of a periodic location registration timer comprises setting an infinite expiration time. In an embodiment, the paging message is submitted over a predetermined area. In a further embodiment, the paging message is submitted during a predetermined paging window. The timing information of the paging window can be delivered from the MTC server to the network. The present invention is typically implemented in an apparatus and a system, wherein the method described above can be performed. Correspondingly the identification information may be stored in the MTC server and delivered from the MTC server to the network; however, other servers may be used for storing this information.

A benefit of the present invention is that it allows the UE to be detached from the network and enables waking up of a user equipment that is in an offline mode in a manner that can be implemented in a low-cost way. The existing 3GPP specifications for the UE do not need to be modified.

Further features and advantages of the invention will become apparent from the following description of preferred embodiments of the invention, given by way of example only, which is made with reference to the accompanying drawings.

Brief Description of the Drawings

Fig. 1 shows a schematic flow chart of an example of a method according to an embodiment of the present invention; and

Fig. 2 shows a schematic block diagram of an example embodiment of the present invention. Detailed Description

Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings.

In Figure 1, a schematic flow chart of an example of a method according to an embodiment of the present invention is shown. In the method, a user equipment is connected to a network, step 10. The user equipment may be any suitable machine type communication device, such as a mobile phone or a machine type communications device designed for a particular purpose. As it is desired that the user equipment will have to suppress its location registration signalling, this is done in step 11. This is done by for example disabling location updating, routing area updating, tracking area updating and similar. These operations can be carried out as described in for example 3GPP TS 23.060 and 3GPP TS 23.401. There may be one or more timers involved in the updating procedure. Timers can be disabled or the expiration time may be set to infinity or at least a very long period that in practice means that the register is not updated. An example of a very long period of time here is a plurality of days or even weeks (whereas the corresponding ordinary period of time for a conventional mobile phone is typically a few hours). Then, the network detaches the user equipment from the network, step 12. This is done locally by the network, which in this context means without signalling to or from the user equipment. This means that the user equipment does not know that it has been detached from the network and acts as if it was attached and remains pageable by the network.

When the need for triggering emerges, the following triggering procedure is initiated for waking up the user equipment that has been detached from the network, step 13. The need for triggering emerges at the machine type communications server side, wherein the server is running software or a service that has a need to contact the user equipment. In this case the server sends a trigger request to the network, step 14. Contrary to the current network implementations, the network accepts the trigger, step 15, even if it knows that the user equipment is not attached to the network. Because the UE is detached from the network, the location of the UE is not known in the network. Because this mechanism is optimally applied only to stationary MTC UEs, the location of the UE is known by the MTC server. The MTC server may deliver the location of the UE to the network with the trigger message.

Finally, the user equipment is paged, step 16. The paging is done for example in accordance with the procedure explained in the standard 3GPP TS 24.301, wherein an IMSI-paging is discussed as an abnormal procedure used for error recovery in the network. As will be well understood, in order to permit this paging, the network keeps at least a minimum set of registration or identity data for the UE after the local detach, and keeps this minimum registration or identity data even after expiry of any "mobile reachable" and "implicit detach" or similar timers, and/or such timers are inhibited for this operation. (As is known, the "mobile reachable" timer and the longer "implicit detach" timer are used conventionally by the network so that if a UE does not perform an expected periodic update, the network effectively erases any registration data for that UE so that the network does not hold registration data for the UE indefinitely, and/or does not attempt to reach the UE indefinitely. It may be for example that the UE has been destroyed or is out of battery power, or rapidly moved out of network coverage, and these timers are conventionally used to prevent the network attempting to contact the UE in such cases after a period of time has elapsed and conventionally prevent the network storing data that has no further purpose.) Notably, by using this paging in this way, the network effectively targets the UE individually, resulting in an efficient mode of operation. In contrast, the CBS (Cell Broadcast System) mentioned above would result in the wake-up trigger being sent to a plurality of UEs and possibly even all UEs in the target area (i.e. the cell covered by the network).

It may be noted that following the local detach by the UE, the network may keep the UE "fully" registered, i.e. the network retains all or practically all of the registration data, security data, etc. for the UE. However, this would effectively tie up a temporary identity used for the UE and the network would maintain a registration state for a UE that typically it does not intend to page any time soon. Another option would be to maintain almost all registration data, but drop the temporary identity and possibly security context, expecting the UE to re-authenticate at next connection. Nevertheless, given that in the preferred example the intention is to trigger the UE to perform a new attach by using IMSI paging, the minimum registration or identity data for the UE that is retained by the network after the local detach is preferably the IMSI for the UE, or at least some other unique identifier for the UE, including for example the IMEI code or an IP address, such as an IPv6 address.

In the PS (packet switched) domain, the UE will consider IMSI paging as a request to synchronise the protocol states between the UE and the network, and the UE performs a local detach, followed by attach. After the attach, the UE makes the session or call setup. The paging procedure is performed over a predetermined area during a predetermined paging period, which is maintained by a machine type communications interworking function. Because the UE is considered detached by the network, the information of its location is not known as such by the network. This can be overcome by the fact that the MTC UEs utilising the present mechanism are often stationary, and their location is known by the MTC server. The location of the UE can be delivered from the MTC server to the network with the triggering message. Additionally or alternatively, the previous known location of the UE may be retained by the network as part of the minimum registration or identity data that is stored for the UE after the local detach by the UE. By knowing the location of the UE despite the local detach, and also retaining some identity data for the UE, the network is able to page the UE in an efficient manner, and does not for example have to send paging messages across the whole cell/plurality of UEs serviced by the network, again minimising the overall signalling that is required.

In an alternative embodiment, instead of signalling the periodic location update timer value as "infinity", the period for UEs could be set to "infinity" by default, or programmed on the application layer. If the operator wants to change this, then signalling is needed from the network to the user equipment. The operator may set a subscriber specific period, or may command the UEs to use the ordinary, broadcast system information based period. This could be done so that the MTC server delivers to the network the information on the MTC UEs that have this behaviour. Another advantage of this solution is that it is not necessary to modify the 3GPP UE specifications, but the operation could be done as a UE implementation (though UE conformance test requirements may not be met).

Figure 2 shows a schematic block diagram of an example embodiment of the present invention. In the drawing, a network is illustrated by a base station 20. An MTC server 21 is communicating with one or more user equipment 22 - 24 through the base station 20. The MTC server does not know if the user equipment 22 - 24 are attached to the base station 20 or not.

In a further embodiment, a safety mechanism against the user equipment and network getting out of synchronisation could be implemented, for example in the case that the MTC interworking function needs to be reset and the timing information for specific user equipment is lost because of that.

The exemplary embodiments of user equipment can include, for example, any suitable servers, workstations, PCs, laptop computers, personal digital assistants (PDAs), Internet appliances, handheld devices, cellular telephones, smart phones, wireless devices, other devices, and the like, capable of performing the processes of the exemplary embodiments. The devices and subsystems of the exemplary embodiments can communicate with each other using any suitable protocol and can be implemented using one or more programmed computer systems or devices.

One or more interface mechanisms for the interface between devices (for example, between UE and base station, or MTC server and base station) can be used with the exemplary embodiments, including, for example, Internet access, telecommunications in any suitable form (e.g. voice, modem and the like), wireless communications media, and the like. For example, employed communications networks or links can include one or more wireless communications networks, cellular communications networks, 3G communications networks, LTE communications networks, Public Switched Telephone Network (PSTNs), Packet Data Networks (PDNs), the Internet, intranets, a combination thereof, and the like.

It is to be understood that the exemplary embodiments are for exemplary purposes, as many variations of the specific hardware used to implement the exemplary embodiments are possible, as will be appreciated by those skilled in the hardware and/or software art(s). For example, the functionality of one or more of the components of the exemplary embodiments can be implemented via one or more hardware and/or software devices.

The exemplary embodiments can store information relating to various processes described herein. This information can be stored in one or more memories, such as a hard disk, optical disk, magneto-optical disk, RAM, and the like. One or more databases can store the information used to implement the exemplary embodiments of the present invention. The databases can be organised using data structures (e.g. records, tables, arrays, fields, graphs, trees, lists and the like) included in one or more memories or storage devices listed herein. The processes described with respect to the exemplary embodiments can include appropriate data structures for storing data collected and/or generated by the processes of the devices and subsystems of the exemplary embodiments in one or more databases.

All or a portion of the exemplary embodiments can be conveniently implemented using one or more general purpose processors, microprocessors, digital signal processors, micro-controllers, and the like, programmed according to the teachings of the exemplary embodiments of the present invention, as will be appreciated by those skilled in the computer and/or software art(s). Appropriate software can be readily prepared by programmers of ordinary skill based on the teachings of the exemplary embodiments, as will be appreciated by those skilled in the software art. In addition, the exemplary embodiments can be implemented by the preparation of application-specific integrated circuits or by interconnecting an appropriate network of conventional component circuits, as will be appreciated by those skilled in the electrical art(s). Thus, the exemplary embodiments are not limited to any specific combination of hardware and/or software.

Stored on any one or on a combination of computer-readable media, the exemplary embodiments of the present invention can include software for controlling the components of the exemplary embodiments, for driving the components of the exemplary embodiments, for enabling the components of the exemplary embodiments to interact with a human user, and the like. Such software can include, but is not limited to, device drivers, firmware, operating systems, development tools, applications software, and the like. Such computer-readable media further can include the computer program product of an embodiment of the present invention for performing all or a portion (if processing is distributed) of the processing performed in implementing the invention. Computer code devices of the exemplary embodiments of the present invention can include any suitable interpretable or executable code mechanism, including but not limited to scripts, interpretable programs, dynamic link libraries (DLLs), Java classes and applets, complete executable programs, Common Object Request Broker Architecture (CORBA) objects, and the like. Moreover, parts of the processing of the exemplary embodiments of the present invention can be distributed for better performance, reliability, cost, and the like.

As stated above, the components of the exemplary embodiments can include computer-readable media or memories for holding instructions programmed according to the teachings of the present invention and for holding data structures, tables, records, and/or other data described herein. Computer-readable media can include any suitable medium that participates in providing instructions to a processor for execution. Such a medium can take many forms, including but not limited to nonvolatile media, volatile media, transmission media, and the like. Non-volatile media can include, for example, optical or magnetic disks, magneto -optical disks, and the like. Volatile media can include dynamic memories, and the like. Transmission media can include coaxial cables, copper wire, fiber optics, and the like. Transmission media also can take the form of acoustic, optical, electromagnetic waves, and the like, such as those generated during radio frequency (RF) communications, infrared (IR) data communications, and the like. Common forms of computer-readable media can include, for example, a floppy disk, a flexible disk, hard disk, magnetic tape, any other suitable magnetic medium, a CD-ROM, CD±R, CD±RW, DVD, DVD-RAM, DVD±RW, DVD±R, HD DVD, HD DVD-R, HD DVD-RW, HD DVD-RAM, Blu-ray Disc, any other suitable optical medium, punch cards, paper tape, optical mark sheets, any other suitable physical medium with patterns of holes or other optically recognisable indicia, a RAM, a PROM, an EPROM, a FLASH-EPROM, any other suitable memory chip or cartridge, a carrier wave or any other suitable medium from which a computer can read.

While the present invention has been described in connection with a number of exemplary embodiments, and implementations, the present invention is not so limited, but rather covers various modifications, and equivalent arrangements, which fall within the purview of the claims.

The above embodiments are to be understood as illustrative examples of the invention. Further embodiments of the invention are envisaged. It is to be understood that any feature described in relation to any one embodiment may be used alone, or in combination with other features described, and may also be used in combination with one or more features of any other of the embodiments, or any combination of any other of the embodiments. Furthermore, equivalents and modifications not described above may also be employed without departing from the scope of the invention, which is defined in the accompanying claims.

Claims

1. A method for detaching and triggering a user equipment, the method comprising:

attaching a user equipment to a telecommunication network;

preventing expiration of a periodic location registration timer;

detaching said user equipment from said network locally by said network with no signalling between the user equipment and the network; and

triggering said user equipment, wherein the triggering comprises:

submitting a trigger from a machine type communications server to said network;

accepting said trigger in said network; and

submitting a paging message from said network to said user equipment, wherein said paging message comprises identification information for providing the paging message to the user equipment.

2. A method according to claim 1 , wherein preventing said expiration of a periodic location registration timer comprises setting a very long expiration time.

3. A method according to claim 1 , wherein preventing said expiration of a periodic location registration timer comprises disabling said periodic location registration timer.

4. A method according to claim 1 , wherein preventing said expiration of a periodic location registration timer comprises setting an infinite expiration time.

5. A method according to any of claims 1 to 4, wherein said paging message is submitted over a predetermined area.

6. A method according to any of claims 1 to 5, wherein said paging message is submitted during a predetermined paging window.

7. A method according to any of claims 1 to 6, wherein the network retains at least one of an International Mobile Subscriber Identity code, an International Mobile Equipment Identity code and an Internet Protocol address for the identification information for the user equipment following the local detach by the user equipment.

8. Apparatus for detaching and triggering a user equipment, the apparatus comprising a wireless telecommunication module for communicating, a memory for storing program code and a processor for executing program code, wherein the apparatus is configured to:

attach a user equipment to a telecommunication network;

prevent expiration of a periodic location registration timer;

detach said user equipment from said network locally with no signalling between the user equipment and the network; and

trigger said user equipment, wherein said apparatus is in the triggering process configured to:

receive a trigger submitted from a machine type communications server to said network;

accept said trigger in said network; and

submit a paging message from said network to said user equipment, wherein said paging message comprises identification information for providing the paging message to the user equipment.

9. Apparatus according to claim 8, wherein said apparatus is configured to prevent said expiration of a periodic location registration timer by setting a very long expiration time.

10. Apparatus according to claim 8, wherein said apparatus is configured to prevent said expiration of a periodic location registration timer comprises by disabling said periodic location registration timer.

11. Apparatus according to claim 8, wherein said apparatus is configured to prevent said expiration of a periodic location registration timer comprises by setting an infinite expiration time.

12. Apparatus according to any of claims 8 to 11, wherein said apparatus is configured to submit said paging message over a predetermined area.

13. Apparatus according to any of claims 8 to 12, wherein apparatus is configured to submit said paging message during a predetermined paging window.

14. Apparatus according to any of claims 8 to 13, wherein the network retains at least one of an International Mobile Subscriber Identity code, an International Mobile Equipment Identity code and an Internet Protocol address for the identification information for said user equipment following the local detach by said user equipment.

15. Apparatus according to any of claims 8 to 14, wherein the apparatus is a network element.

16. Apparatus according to any of claims 8 to 15, wherein the apparatus is an eNodeB of an LTE network.

17. A system for detaching and triggering a user equipment, the system comprising:

at least one user equipment;

at least one machine type communications server; and

at least one network element;

wherein the system is configured to:

attach a user equipment to a telecommunication network;

prevent expiration of a periodic location registration timer of the user equipment; detach said user equipment from said network locally by said network with no signalling between the user equipment and the network; and

trigger said user equipment, wherein said network element is in the triggering process configured to:

accept said trigger in said network; and

18. A system according to claim 17, wherein said network element is configured to prevent said expiration of a periodic location registration timer by signalling a very long or infinite expiration time to said at least one user equipment.

19. A system according to claim 17, wherein said network element is configured to prevent said expiration of a periodic location registration timer by disabling said periodic location registration timer by signalling from said network element to said at least one user equipment.

20. A system according to any of claims 17 to 19, wherein said network element is configured to submit said paging message over a predetermined area.

21. A system according to any of claims 17 to 20, wherein the network element is configured to submit said paging message during a predetermined paging window.

22. A system according to any of claims 17 to 21, wherein the network retains at least one of an International Mobile Subscriber Identity code, an International Mobile Equipment Identity code and an Internet Protocol address for the identification information for said user equipment following the local detach by said user equipment.

23. A system according to any of claims 17 to 22, wherein the system is an LTE network.