WO2023044822A1

WO2023044822A1 - Parameter update for connection resume attempt

Info

Publication number: WO2023044822A1
Application number: PCT/CN2021/120487
Authority: WO
Inventors: Samuli Heikki TURTINEN; Jussi-Pekka Koskinen; Chunli Wu
Original assignee: Nokia Shanghai Bell Co., Ltd.; Nokia Solutions And Networks Oy; Nokia Technologies Oy
Priority date: 2021-09-24
Filing date: 2021-09-24
Publication date: 2023-03-30

Abstract

Example embodiments of the present disclosure relate to devices, methods, apparatuses and computer readable storage media for parameter update for a connection resume attempt. In example embodiments, a terminal device in an inactive mode obtains one or more updated parameters by updating one or more currently configured parameters based on an update pattern. The terminal device in the inactive mode initiates a connection resume attempt using the one or more updated parameters.

Description

PARAMETER UPDATE FOR CONNECTION RESUME ATTEMPT

FIELD

Example embodiments of the present disclosure generally relate to the field of communications, and in particular, to devices, methods, apparatuses and computer readable storage media for parameter update for a connection resume attempt.

BACKGROUND

Three Small Data Transmission (SDT) types are defined in 3rd Generation Partnership Project (3GPP) Release 17 (REL17) , which include 4-step Random Access Channel (RACH) based SDT (4-step RA SDT) , 2-step RACH based SDT (2-step RA SDT) and Configured Grant based Physical Uplink Shared Channel (PUSCH) transmission (CG-SDT) . In 4-step RA SDT, the Message 3 (Msg3) (PUSCH) can be used by user equipment (UE) to transmit SDT payload. In 2-step RA SDT, the Message A (MsgA) PUSCH can be used by the UE to transmit the SDT payload. In CG-SDT, a Configured Grant type 1 based PUSCH resource can be used by the UE to transmit the SDT payload if the UE has a valid timing advance (TA) , for example, without a random access procedure.

During or after an SDT procedure, the UE could initiate a new SDT procedure or resume procedure, for example, after an RRCReject message for SDT or non-SDT data arrival during a SDT procedure. The main issue with this is a security issue due to reuse of input parameters for calculating resumeMAC-I in a Common Control Channel (CCCH) message to initiate the new SDT procedure or the resume procedure.

SUMMARY

In general, example embodiments of the present disclosure provide devices, methods, apparatuses and computer readable storage media for a parameter update for a connection resume attempt.

In a first aspect, a terminal device is provided which comprises at least one processor and at least one memory including computer program code. The at least one memory and the computer program code are configured to, with the at least one processor, cause the terminal device to obtain, in an inactive mode, one or more updated parameters by updating one or more currently configured parameters based on an update pattern. The terminal device is further caused to initiate, in the inactive mode, a connection resume attempt using the one or more updated parameters.

In a second aspect, a network device is provided which comprises at least one processor and at least one memory including computer program code. The at least one memory and the computer program code are configured to, with the at least one processor, cause the network device to determine an update pattern for one or more currently configured parameters to be used by a terminal device in an inactive mode to initiate a connection resume attempt. The network device is caused to send, to the terminal device, an indication of the update pattern for the one or more currently configured parameters. The network device is further caused to detect the connection resume attempt from the terminal device, using one or more updated parameters generated by updating the one or more parameters based on the update pattern.

In a third aspect, a method is provided. In the method, a terminal device in an inactive mode obtains one or more updated parameters by updating one or more currently configured parameters based on an update pattern. The terminal device in the inactive mode initiates a connection resume attempt using the one or more updated parameters.

In a fourth aspect, a method is provided. In the method, a network device determines an update pattern for one or more currently configured parameters to be used by a terminal device in an inactive mode to initiate a connection resume attempt. The network device sends, to the terminal device, an indication of the update pattern for the one or more currently configured parameters. The network device detects the connection resume attempt from the terminal device, using one or more updated parameters generated by updating the one or more parameters based on the update pattern.

In a fifth aspect, there is provided an apparatus comprising means for performing the method according to the third or fourth aspect.

In a sixth aspect, there is provided a computer readable storage medium comprising program instructions stored thereon. The instructions, when executed by a processor of a device, cause the device to perform the method according to the third or fourth aspect.

It is to be understood that the summary section is not intended to identify key or essential features of example embodiments of the present disclosure, nor is it intended to be used to limit the scope of the present disclosure. Other features of the present disclosure will become easily comprehensible through the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

Some example embodiments will now be described with reference to the accompanying drawings, where:

FIG. 1 illustrates an example environment in which example embodiments of the present disclosure can be implemented;

FIG. 2 illustrates a flowchart of an example method according to some example embodiments of the present disclosure;

FIG. 3 illustrates a flowchart of an example method according to some other example embodiments of the present disclosure;

FIG. 4 illustrates an example process for connection resume according to some example embodiments of the present disclosure; and

FIG. 5 illustrates a simplified block diagram of a device that is suitable for implementing example embodiments of the present disclosure.

Throughout the drawings, the same or similar reference numerals represent the same or similar element.

DETAILED DESCRIPTION

Principle of the present disclosure will now be described with reference to some example embodiments. It is to be understood that these example embodiments are described only for the purpose of illustration and help those skilled in the art to understand and implement the present disclosure, without suggesting any limitation as to the scope of the disclosure. The disclosure described herein can be implemented in various manners other than the ones described below.

In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skills in the art to which this disclosure belongs.

As used herein, the term “terminal device” or “user equipment” (UE) refers to any terminal device capable of wireless communications with each other or with the base station. The communications may involve transmitting and/or receiving wireless signals using electromagnetic signals, radio waves, infrared signals, and/or other types of signals suitable for conveying information over air. In some example embodiments, the UE may be configured to transmit and/or receive information without direct human interaction. For example, the UE may transmit information to the base station on predetermined schedules, when triggered by an internal or external event, or in response to requests from the network side.

Examples of the UE include, but are not limited to, smart phones, wireless-enabled tablet computers, laptop-embedded equipment (LEE) , laptop-mounted equipment (LME) , wireless customer-premises equipment (CPE) , sensors, metering devices, personal wearables such as watches, and/or vehicles that are capable of communication. For the purpose of discussion, some example embodiments will be described with reference to UEs as examples of the terminal devices, and the terms “terminal device” and “user equipment” (UE) may be used interchangeably in the context of the present disclosure.

As used herein, the term “network device” refers to a device via which services can be provided to a terminal device in a communication network. As an example, the network device may comprise a base station. As used herein, the term “base station” (BS) refers to a network device via which services can be provided to a terminal device in a communication network. The base station may comprise any suitable device via which a terminal device or UE can access the communication network. Examples of the base stations include a relay, an access point (AP) , a transmission point (TRP) , a node B (NodeB or NB) , an evolved NodeB (eNodeB or eNB) , a New Radio (NR) NodeB (gNB) , a Remote Radio Module (RRU) , a radio header (RH) , a remote radio head (RRH) , a low power node such as a femto, a pico, and the like.

As used herein, the term “circuitry” may refer to one or more or all of the following:

(a) hardware-only circuit implementations (such as implementations in only analog and/or digital circuitry) and

(b) combinations of hardware circuits and software, such as (as applicable) : (i) a combination of analog and/or digital hardware circuit (s) with software/firmware and (ii) any portions of hardware processor (s) with software (including digital signal processor (s) ) , software, and memory (ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions) and

(c) hardware circuit (s) and or processor (s) , such as a microprocessor (s) or a portion of a microprocessor (s) , that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation.

This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and/or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in a server, a cellular base station, or other computing or base station.

As used herein, the singular forms “a” , “an” , and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. The term “includes” and its variants are to be read as open terms that mean “includes, but is not limited to” . The term “based on” is to be read as “based at least in part on” . The term “one embodiment” and “an embodiment” are to be read as “at least one embodiment” . The term “another embodiment” is to be read as “at least one other embodiment” . Other definitions, explicit and implicit, may be included below.

As used herein, the terms “first” , “second” and the like may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be referred to as a second element, and similarly, a second element could be termed a first element, without departing from the scope of example embodiments. As used herein, the term “and/or” includes any and all combinations of one or more of the listed terms.

As discussed above, the UE could initiate new SDT procedure or resume procedure, for example, after a RRCReject message for SDT or non-SDT data arrival during a SDT procedure or occurrence of cell reselection during a SDT procedure. In a Common Control Channel (CCCH) based approach, the new SDT procedure is initiated after an event (e.g., after a RRCReject message for SDT or non-SDT data arrival during a SDT procedure or occurrence of cell reselection during a SDT procedure) . A Dedicated Control Channel (DCCH) based approach for non-SDT data arrival could only indicate the non-SDT data arrival during SDT but could not overcome other SDT procedure terminations, for example, due to RRCReject. This is because in the DCCH based approach, the non-SDT data arrival is indicated in the SDT procedure using a newly defined RRC message over the DCCH logical channel. Therefore, the option for supporting the CCCH based approach would be preferable as it can support different cases.

The main issue with the CCCH based approach is a security issue. For example, in the first SDT message, the UE may already transmit data secured with a key generated. When a network (NW) responds, for example, with RRCReject, or non-SDT data appears in a UE buffer, initiating a new SDT procedure with the same key would impose a security threat in case a Packet Data Convergence Protocol (PDCP) entity for a Data Radio Bearer (DRB) for which data was already transmitted would be re-established.

Moreover, the security threat is also present for an RRCResumeRequest message since the generated resumeMAC-I would remain until the input parameters used to generate the resumeMAC-I would be changed. To circumvent replay attacks, the reuse of resumeMAC-I should be avoided. The input parameters for calculating resumeMAC-I may include KEY, PDCP COUNT, MESSAGE, DIRECTION and BEARER. A change in any input parameter will be sufficient for producing a different resumeMAC-I and avoiding its reuse.

However, changing the parameters will necessarily mean blind decoding at the NW side. Furthermore, it could be easily attacked to just update or count one of the parameters up, for example, in ascending order, by the UE.

Example embodiments of the present disclosure provide a scheme for parameter update for a connection resume attempt such as resumeMAC-I in RRCResumeRequest. With this scheme, a network device configures an update pattern for one or more currently configured parameters that are to be used by a terminal device in an inactive mode to initiate a connection resume attempt. As an example, the network device may send an indication of the update pattern to the terminal device when releasing the terminal device from a connected mode (such as RRC_CONNECTED mode) to an inactive mode (such as RRC_INACTIVE mode) . As another example, the update pattern for one or more currently configured parameters that are to be used by a terminal device in an inactive mode to initiate a connection resume attempt could be pre-defined (e.g., in a technical specification) . As another example, the update pattern for a first set of one or more currently configured parameters that are to be used by a terminal device in an inactive mode to initiate a connection resume attempt may be configured by a network device while the update pattern for a second set of one or more currently configured parameters that are to be used by a terminal device in an inactive mode to initiate a connection resume attempt may be pre-defined (e.g., in a technical specification) .

Accordingly, based on the update pattern, the terminal device determines how the currently configured parameters are to be updated upon need for a connection resume attempt (for example, either for SDT or non-SDT) . The terminal device uses one or more updated parameters obtained by updating the one or more currently configured parameters based on the update pattern to initiate the connection resume attempt.

The configuration of the update pattern would bring convenience to the network device, for example, due to less blind decoding. The network device may perform less blind detections for determining the input parameters used for updated resumeMAC-I as the network device configures how the update of the input parameters is done. Moreover, configuration of the update pattern brings secure. Since the update pattern for the input parameters is configured by the network device and provided to the terminal device, it is hard for an attacker to deduce how the input parameter update is done by the terminal device upon resume attempts.

FIG. 1 shows an example environment 100 in which example embodiments of the present disclosure can be implemented.

The environment 100, which may be a part of a communication network, comprises a network device 110 and a terminal device 120 that can communicate with each other. It is to be understood that two devices are shown in the environment 100 only for the purpose of illustration, without suggesting any limitation to the scope of the present disclosure. In some example embodiments, the environment 100 may comprise any suitable numbers of network devices and terminal devices.

The communications in the environment 100 may follow any suitable communication standards or protocols, which are already in existence or to be developed in the future, such as Universal Mobile Telecommunications System (UMTS) , long term evolution (LTE) , LTE-Advanced (LTE-A) , the fifth generation (5G) New Radio (NR) , Wireless Fidelity (Wi-Fi) and Worldwide Interoperability for Microwave Access (WiMAX) standards, and employs any suitable communication technologies, including, for example, Multiple-Input Multiple-Output (MIMO) , Orthogonal Frequency Division Multiplexing (OFDM) , time division multiplexing (TDM) , frequency division multiplexing (FDM) , code division multiplexing (CDM) , Bluetooth, ZigBee, and machine type communication (MTC) , enhanced mobile broadband (eMBB) , massive machine type communication (mMTC) , ultra-reliable low latency communication (URLLC) , Carrier Aggregation (CA) , Dual Connection (DC) , and New Radio Unlicensed (NR-U) technologies.

In the environment 100, the terminal device 120 can transmit SDT data and non-SDT data. In the context of the present disclosure, non-SDT data refers to data on a data radio bearer (DRB) or a signalling radio bearer (SRB) that is not configured for SDT. When the terminal device 120 is an inactive state (such as RRC_INACTIVE mode) , the terminal device 120 may initiate a connection resume attempt. For example, if non-SDT data is arrived or cell reselection is to be performed during a SDT procedure, if the SDT procedure is rejected by the network device 110, if a SDT failure timer is expired, or if a radio link control (RLC) entity reaches a configured maximum number of retransmissions, the terminal device 120 may initiate the connection resume attempt.

In various example embodiments of the present disclosure, the network device 110 configures an update pattern for one or more currently configured parameters to be used by the terminal device 120 in an inactive mode to initiate a connection resume attempt. Accordingly, the terminal device 120 in the inactive mode obtains one or more updated parameters by updating the one or more currently configured parameters based on the update pattern and uses the one or more updated parameters to initiate the connection resume attempt.

FIG. 2 shows a flowchart of an example method 200 according to some example embodiments of the present disclosure. The method 200 may be implemented by the terminal device 120. For the purpose of discussion, the method 200 will be described with reference to FIG. 1.

At block 205, the terminal device 120 receives, from the network device 110, an indication of an update pattern for one or more currently configured parameters to be used to initiate a connection resume attempt in an inactive mode (such as RRC_INACTIVE mode) . For example, the parameters may comprise input parameters (KEY, PDCP COUNT, MESSAGE DIRECTION, BEARER) that have been configured, for example, by the network device 110 and have certain values to generate resumeMAC-I. The current values of these parameters may be indicated by the network device 110 in advance or may be specified or predefined. For example, the values may be binary one “1” by default or some other values indicated in SRB0. The indication of the update pattern transmitted from network device 110 to the terminal device 120 may indicate the update pattern. For example, this may mean that the update pattern is provided by the network device 110 to the terminal device 120.

In some example embodiments, the update pattern is provided for one or more parameters to be used to generate resumeMAC-I. Thus, in some embodiments, the parameter (s) may comprise a parameter that is currently configured and/or not currently configured. Therefore, the embodiments described herein may additionally or alternatively be used in updating parameter (s) that are not currently configured.

The update pattern may be associated with any suitable features of the currently configured parameters for a connection resume attempt. For example, the update pattern may comprise a step size to update a respective parameter of the parameters. Accordingly, the terminal device 120 may change the respective parameters by the step sizes. Alternatively or in addition, the update pattern may comprise an order to update the parameters so that the terminal device 120 updates the parameters in the order one by one. Alternatively or in addition, the update pattern may comprise identifications of the one or more parameters to inform the terminal device 120 which parameter is to be updated. For example, the update pattern may indicate that one of the parameters (for example, PDCP COUNT used for resumeMAC-I generation) is to be updated.

The indication of the update pattern from the network device 110 may be received by the terminal device 120 when in a connected mode (such as RRC_CONNECTED mode) . For example, the terminal device 120 may receive a release message from the network device 110 to release the terminal device 120 from the connected mode to the inactive mode. The release message may contain the indication of the update pattern for the one or more currently configured parameters.

Block 205 in FIG. 2 is optional. In some example embodiments, the update pattern could be pre-defined (for example, in a technical specification) . In some other example embodiments, the update pattern for a first set of one or more currently configured parameters to initiate a connection resume attempt may be configured by the network device 110 while the update pattern for a second set of one or more currently configured parameters to initiate a connection resume attempt may be pre-defined (for example, in a technical specification) .

At block 210, when in the inactive mode, the terminal device 120 obtains one or more updated parameters by updating the one or more currently configured parameters based on the update pattern. For example, if the update pattern indicates one of the parameters (for example, PDCP COUNT used for resumeMAC-I generation) is to be updated based on a step size, the terminal device 120 may increase or decrease the one of the parameters by the indicated step size. As another example, if the update pattern indicates an order of the plurality of parameters, the terminal device 120 may update one of the parameters each time in the indicated order.

The updated parameters may be determined by the terminal device 120 when a connection resume attempt is needed. For example, if non-SDT data arrives at an uplink data buffer at the terminal device 120 or cell reselection is to be performed during a SDT procedure, if the SDT procedure is rejected by the network device 110, if a SDT failure timer is expired, or if a RLC entity reaches a configured maximum number of retransmissions, the terminal device 120 may obtain the updated parameters based on the update pattern. As such, the CCCH based re-attempt may support more use cases including SDT rejection, non-SDT data arrival, cell reselection or the like.

At block 215, the terminal device 120 in the inactive mode initiates the connection resume attempt using the one or more updated parameters. For example, the terminal device 120 generates a connection resume request using the one or more updated parameters and initiates the connection resume attempt with the connection resume request. The connection resume request may contain resumeMAC-I generated based on the one or more updated parameters.

In some example embodiments, the connection resume request may be used to initiate a connection resume procedure. In this case, for example, the terminal device 120 may not perform a SDT procedure with the updated resumeMAC-I but only perform a non-SDT procedure (for example, a regular RRC Resume procedure) , after a SDT procedure has been rejected or upon non-SDT data arrival or cell reselection during the SDT procedure. Based on the updated resumeMAC-I, the network device 110 may deduce that the terminal device 120 has performed SDT previously and may trigger a change of the parameter KEY for the SDT data bearer (such as SDT DRB) or other bearers when the connection is resumed. The network device 110 may also trigger PDCP entity (or entities) re-establishment for SDT-DRBs as these may have already used the key for data upon the previous SDT transmission. Accordingly, upon the completion of the connection resume procedure, the terminal device 120 may receive an indication of a changed value of the KEY from the network device 110.

In some other example embodiments, the connection resume request may be used to initiate a new SDT procedure. For example, the terminal device 120 may perform a new SDT procedure with the updated resumeMAC-I. In some example embodiments, for the parameter COUNT, in addition to updating the parameter COUNT for the connection resume attempt (which is one of the currently configured parameters) based on the configured update pattern, the terminal device 120 may update the parameter COUNT for a SDT data bearer based on the configured update pattern. For example, the terminal device 120 may not only update the COUNT value for resumeMAC-I generation, but also update the COUNT value for the data bearer (s) that is using the SDT procedure. This may avoid attacker to deduce how many attempts the terminal device 120 have made in case the COUNT value for the data bearer (s) would be just increased as usual.

In some example embodiments, the terminal device 120 may receive from the network device 110 an indication whether the one or more currently configured parameters is allowed to be updated. The indication may be received in a connection rejection message such as a RRC Reject message. If the update is allowed, the terminal device 120 update the parameters based on the update pattern. If the update is disallowed, the terminal device 120 may enter an idle mode from the inactive mode.

In some example embodiments, the number of parameter update may be limited by the number of connection resume attempts. For example, the number of connection resume attempts initiated by updating the one or more currently configured parameters is above a threshold number, the terminal device 120 may enter an idle mode from the inactive mode. In some example embodiments, the maximum number of resume attempts may be specified in advance. According to the specification, the terminal device 120 may know how many resume attempts is allowed to be performed by updating the input parameters. In some other example embodiments, the maximum number of resume attempts may be configured by the network device 110 and sent to the terminal device 120.

FIG. 3 shows a flowchart of an example method 300 according to some example embodiments of the present disclosure. The method 300 may be implemented by the network device 110. For the purpose of discussion, the method 300 will be described with reference to FIG. 1.

At block 305, the network device 110 determines an update pattern for one or more currently configured parameters to be used by the terminal device 120 in an inactive mode to initiate a connection resume attempt. For example, the network device 110 may configure which input parameter (KEY, PDCP COUNT, MESSAGE DIRECTION, BEARER) the UE shall update and with which step size. In some example embodiments, the network device 110 may configure an order for the input parameters in which they need to be updated by the terminal device 120. In some example embodiments, it may be specified that one of the parameter (for example, PDCP COUNT used for resumeMAC-I generation) is updated while the update pattern is configured by the network device 110.

At block 310, the network device 110 sends to the terminal device 120 an indication of the update pattern for the one or more currently configured parameters. For example, upon releasing the terminal device 120 to an inactive mode such as RRC_INACTIVE mode, the network device 110 may send an indication how the input parameters for resumeMAC-I is to be updated by the terminal device 120 to generate a new resumeMAC-I for a connection resume attempt (either for SDT or non-SDT) .

At block 315, using one or more updated parameters generated by updating the one or more parameters based on the update pattern, the network device 110 detects the connection resume attempt from the terminal device 120. For example, the network device 110 may detect a connection resume request from the terminal device 120, using the one or more updated parameters. The connection resume request may contain resumeMAC-I generated based on the one or more updated parameters.

In some example embodiments, the terminal device 120 may not perform a SDT procedure with the updated resumeMAC-I but only perform a non-SDT procedure (such as a regular RRC Resume procedure) , for example, after SDT procedure has been rejected, or upon non-SDT data arrival or cell reselection during the SDT procedure. Based on the updated resumeMAC-I, the network device 110 may deduce that the terminal device 120 has performed SDT previously. In this case, the network device 110 may trigger a key change and PDCP entity (ies) re-establishment for SDT-DRBs (as these may have already used the key for data upon the SDT transmission) when the connection is resumed. For example, upon completion of a connection resume procedure initiated by the terminal device 120, the network device 110 may transmit to the terminal device 120 an indication of a changed value of the key for bearers including SDT DRBs or other bearers.

In some example embodiments, the network device 110 may configure how many resume attempts the terminal device 120 can perform by updating the input parameters. After the maximum number of resume attempts have been performed, the terminal device 120 may go to an IDLE mode.

In some example embodiments, the network device 110 may indicate to the terminal device 120 whether or not input parameters shall be updated. In case input parameter update is not allowed, the terminal device 120 may go to an IDLE mode. The indication may be transmitted in a connection reject message such as a RRC Reject message.

All operations and features as described above with reference to FIGS. 1 and 2 are likewise applicable to the method 300 at the network device 110 and have similar effects. For the purpose of simplification, the details will be omitted.

FIG. 4 shows an example process 400 for connection resume according to some example embodiments of the present disclosure. In this example, the terminal device 120 is implemented by a UE 405, and the network device 110 is implemented by a gNB 410.

As shown, at 415, the UE 405 is in a connected mode. At 420, the gNB 410 110 sends to the UE 405 RRCRelease with suspendConfig containing SDT configuration that includes an update pattern for resumeMAC-I input parameters. At 425, the UE 405 performs SDT initiation. At 430, the UE 405 initiates a SDT resume attempt with resumeMAC-I. At 435, non-SDT data arrives into a buffer at the UE 405. Alternatively, At 440, the UE 405 receives SDT rejection from the gNB 410. At 445, the UE 405 triggers a new resume procedure (SDT or non-SDT) . At 450, the UE 405 updates the input parameters of resumeMAC-I based on the configured update pattern and generates new resumeMAC-I. At 455, the UE 405 initiates resume attempt with new resumeMAC-I.

FIG. 5 is a simplified block diagram of a device 500 that is suitable for implementing example embodiments of the present disclosure.

As shown, the device 500 includes a processor 510, a memory 520 coupled to the processor 510, a communication module 530 coupled to the processor 510, and a communication interface (not shown) coupled to the communication module 530. The memory 520 stores at least a program 540. The communication module 530 is for bidirectional communications, for example, via multiple antennas. The communication interface may represent any interface that is necessary for communication.

The program 540 is assumed to include program instructions that, when executed by the associated processor 510, enable the device 500 to operate in accordance with the example embodiments of the present disclosure, as discussed herein with reference to FIGS. 1-4. The example embodiments herein may be implemented by computer software executable by the processor 510 of the device 500, or by hardware, or by a combination of software and hardware. The processor 510 may be configured to implement various example embodiments of the present disclosure.

The memory 520 may be of any type suitable to the local technical network and may be implemented using any suitable data storage technology, such as a non-transitory computer readable storage medium, semiconductor based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory, as non-limiting examples. While only one memory 520 is shown in the device 500, there may be several physically distinct memory modules in the device 500. The processor 510 may be of any type suitable to the local technical network, and may include one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multicore processor architecture, as non-limiting examples. The device 500 may have multiple processors, such as an application specific integrated circuit chip that is slaved in time to a clock which synchronizes the main processor.

When the device 500 acts as the terminal device 120, the processor 510 and the communication module 530 may cooperate to implement the method 200 as described above with reference to FIGS. 1-2. When the device 500 acts as the network device 110, the processor 510 and the communication module 530 may cooperate to implement the method 300 as described above with reference to FIGS. 1-3. All operations and features as described above with reference to FIGS. 1-4 are likewise applicable to the device 500 and have similar effects. For the purpose of simplification, the details will be omitted.

Generally, various example embodiments of the present disclosure may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device. While various aspects of example embodiments of the present disclosure are illustrated and described as block diagrams, flowcharts, or using some other pictorial representations, it is to be understood that the block, apparatus, system, technique or method described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

The present disclosure also provides at least one computer program product tangibly stored on a non-transitory computer readable storage medium. The computer program product includes computer-executable instructions, such as those included in program modules, being executed in a device on a target real or virtual processor, to carry out the

method

200 or 300 or the process 400 as described above with reference to FIGS. 1-4. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, or the like that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or split between program modules as desired in various example embodiments. Machine-executable instructions for program modules may be executed within a local or distributed device. In a distributed device, program modules may be located in both local and remote storage media.

Program code for carrying out methods of the present disclosure may be written in any combination of one or more programming languages. These program codes may be provided to a processor or controller of a general purpose computer, special purpose computer, or other programmable data processing apparatus, such that the program codes, when executed by the processor or controller, cause the functions/operations specified in the flowcharts and/or block diagrams to be implemented. The program code may execute entirely on a machine, partly on the machine, as a stand-alone software package, partly on the machine and partly on a remote machine or entirely on the remote machine or server.

In the context of the present disclosure, the computer program codes or related data may be carried by any suitable carrier to enable the device, apparatus or processor to perform various processes and operations as described above. Examples of the carrier include a signal, computer readable media.

The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable medium may include but not limited to an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of the computer readable storage medium would include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM) , a read-only memory (ROM) , an erasable programmable read-only memory (EPROM or Flash memory) , an optical fiber, a portable compact disc read-only memory (CD-ROM) , Digital Versatile Disc (DVD) , an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

Further, while operations are depicted in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Likewise, while several specific implementation details are contained in the above discussions, these should not be construed as limitations on the scope of the present disclosure, but rather as descriptions of features that may be specific to particular example embodiments. Certain features that are described in the context of separate example embodiments may also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment may also be implemented in multiple example embodiments separately or in any suitable sub-combination.

Although the present disclosure has been described in languages specific to structural features and/or methodological acts, it is to be understood that the present disclosure defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Various example embodiments of the techniques have been described. In addition to or as an alternative to the above, the following examples are described. The features described in any of the following examples may be utilized with any of the other examples described herein.

In some aspects, a terminal device comprises: at least one processor; and at least one memory including computer program code; the at least one memory and the computer program code configured to, with the at least one processor, cause the terminal device to: obtain, in an inactive mode, one or more updated parameters by updating one or more currently configured parameters based on an update pattern; and initiate, in the inactive mode, a connection resume attempt using the one or more updated parameters.

In some example embodiments, the terminal device is further caused to receive, from a network device, an indication of the update pattern.

In some example embodiments, the one or more updated parameters are obtained in response to at least one of: arrival of non-small data transmission data during a small data transmission procedure; cell reselection during the small data transmission procedure; rejection of the small data transmission procedure; expiry of a small data transmission failure timer; or a radio link control entity reaching a configured maximum number of retransmissions.

In some example embodiments, the terminal device is caused to initiate the connection resume attempt using the one or more updated parameters by: generating a connection resume request using the one or more updated parameters; and initiating the connection resume attempt with the connection resume request.

In some example embodiments, the connection resume request contains resumeMAC-I generated based on the one or more updated parameters.

In some example embodiments, the terminal device is caused to initiate the connection resume attempt by: initiating a connection resume procedure with the connection resume request to initiate the connection resume attempt.

In some example embodiments, the one or more currently configured parameters comprise a key for a bearer, and the terminal device is further caused to: in response to completion of the connection resume procedure, receive, from the network device, an indication of a changed value of the key for the bearer.

In some example embodiments, the terminal device is caused to initiate the connection resume attempt by initiating a new small data transmission procedure with the connection resume request to initiate the connection resume attempt.

In some example embodiments, the one or more currently configured parameters comprise a count for the connection resume attempt, and the terminal device is further caused to: update a count for a small data transmission data bearer using the update pattern.

In some example embodiments, the indication of the update pattern is received by the terminal device in a connected mode in a release message to release the terminal device from the connected mode to the inactive mode.

In some example embodiments, the update pattern comprises at least one of: a step size to update a respective parameter of the one or more currently configured parameters; an order to update the one or more currently configured parameters; or identifications of the one or more currently configured parameters.

In some example embodiments, the terminal device is caused to obtain the one or more updated parameters by: receiving, from the network device, an indication whether the one or more currently configured parameters is allowed to be updated; and in response to the one or more currently configured parameters being allowed to be updated, updating the one or more currently configured parameters based on the update pattern to obtain the one or more updated parameters.

In some example embodiments, the terminal device is further caused to: in response to the one or more currently configured parameters being disallowed to be updated, enter an idle mode from the inactive mode.

In some example embodiments, the indication whether the one or more currently configured parameters is allowed to be updated is received in a connection reject message.

In some example embodiments, the terminal device is further caused to: in response to a number of connection resume attempts initiated by updating the one or more currently configured parameters being above a threshold number, enter an idle mode from the inactive mode.

In some example embodiments, the terminal device is further caused to: receive, from the network device, an indication of the threshold number.

In some aspects, a network device comprises: at least one processor; and at least one memory including computer program code; the at least one memory and the computer program code configured to, with the at least one processor, cause the network device to: determine an update pattern for one or more currently configured parameters to be used by a terminal device in an inactive mode to initiate a connection resume attempt; send, to the terminal device, an indication of the update pattern for the one or more currently configured parameters; and detect the connection resume attempt from the terminal device, using one or more updated parameters generated by updating the one or more parameters based on the update pattern.

In some example embodiments, the network device is caused to detect the connection resume attempt by: detecting a connection resume request from the terminal device, using the one or more updated parameters.

In some example embodiments, the one or more currently configured parameters comprise a key for a bearer, and the network device is further caused to: in response to completion of a connection resume procedure initiated by the terminal device with the connection resume request, transmit, to the terminal device, an indication of a changed value of the key for the bearer.

In some example embodiments, the network device is further caused to: transmit, to the terminal device, an indication whether the one or more currently configured parameters is allowed to be updated.

In some example embodiments, the indication whether the one or more currently configured parameters is transmitted in a connection reject message.

In some example embodiments, the network device is further caused to: transmit, to the terminal device, an indication of a threshold number of connection resume attempts initiated by updating the one or more currently configured parameters.

In some aspects, a method comprises: obtaining, by a terminal device in an inactive mode, one or more updated parameters by updating one or more currently configured parameters based on an update pattern; and initiating, by the terminal device in the inactive mode, a connection resume attempt using the one or more updated parameters.

In some example embodiments, the method further comprises: receiving, from a network device, an indication of the update pattern.

In some example embodiments, initiating the connection resume attempt using the one or more updated parameters comprises: generating a connection resume request using the one or more updated parameters; and initiating the connection resume attempt with the connection resume request.

In some example embodiments, initiating the connection resume attempt comprises: initiating a connection resume procedure with the connection resume request to initiate the connection resume attempt.

In some example embodiments, the one or more currently configured parameters comprise a key for a bearer, and the method further comprises: in response to completion of the connection resume procedure, receiving, from the network device, an indication of a changed value of the key for the bearer.

In some example embodiments, initiating the connection resume attempt comprises: initiating a new small data transmission procedure with the connection resume request to initiate the connection resume attempt.

In some example embodiments, the one or more currently configured parameters comprise a count for the connection resume attempt, and the method further comprises: updating a count for a small data transmission data bearer using the update pattern.

In some example embodiments, obtaining the one or more updated parameters comprises: receiving, from the network device, an indication whether the one or more currently configured parameters is allowed to be updated; and in response to the one or more currently configured parameters being allowed to be updated, updating the one or more currently configured parameters based on the update pattern to obtain the one or more updated parameters.

In some example embodiments, the method further comprises: in response to the one or more currently configured parameters being disallowed to be updated, entering an idle mode from the inactive mode.

In some example embodiments, the method further comprises: in response to a number of connection resume attempts initiated by updating the one or more currently configured parameters being above a threshold number, entering an idle mode from the inactive mode.

In some example embodiments, the method further comprises: receiving, from the network device, an indication of the threshold number.

In some aspects, a method comprises: determining, by a network device, an update pattern for one or more currently configured parameters to be used by a terminal device in an inactive mode to initiate a connection resume attempt; sending, by the network device to the terminal device, an indication of the update pattern for the one or more currently configured parameters; and detecting, by the network device, the connection resume attempt from the terminal device, using one or more updated parameters generated by updating the one or more parameters based on the update pattern.

In some example embodiments, detecting the connection resume attempt comprises: detecting a connection resume request from the terminal device, using the one or more updated parameters.

In some example embodiments, the one or more currently configured parameters comprise a key for a bearer, and the method further comprises: in response to completion of a connection resume procedure initiated by the terminal device with the connection resume request, transmitting, to the terminal device, an indication of a changed value of the key for the bearer.

In some example embodiments, the method further comprises: transmitting, to the terminal device, an indication whether the one or more currently configured parameters is allowed to be updated.

In some example embodiments, the method further comprises: transmitting, to the terminal device, an indication of a threshold number of connection resume attempts initiated by updating the one or more currently configured parameters.

In some aspects, an apparatus comprises: means for obtaining, by a terminal device in an inactive mode, one or more updated parameters by updating one or more currently configured parameters based on an update pattern; and means for initiating, by the terminal device in the inactive mode, a connection resume attempt using the one or more updated parameters.

In some example embodiments, the apparatus further comprises: means for receiving, from a network device, an indication of the update pattern.

In some example embodiments, the means for initiating the connection resume attempt using the one or more updated parameters comprises: means for generating a connection resume request using the one or more updated parameters; and means for initiating the connection resume attempt with the connection resume request.

In some example embodiments, the means for initiating the connection resume attempt comprises: means for initiating a connection resume procedure with the connection resume request to initiate the connection resume attempt.

In some example embodiments, the one or more currently configured parameters comprise a key for a bearer, and the apparatus further comprises: means for in response to completion of the connection resume procedure, receiving, from the network device, an indication of a changed value of the key for the bearer.

In some example embodiments, the means for initiating the connection resume attempt comprises: means for initiating a new small data transmission procedure with the connection resume request to initiate the connection resume attempt.

In some example embodiments, the one or more currently configured parameters comprise a count for the connection resume attempt, and the apparatus further comprises: means for updating a count for a small data transmission data bearer using the update pattern.

In some example embodiments, the means for obtaining the one or more updated parameters comprises: means for receiving, from the network device, an indication whether the one or more currently configured parameters is allowed to be updated; and means for in response to the one or more currently configured parameters being allowed to be updated, updating the one or more currently configured parameters based on the update pattern to obtain the one or more updated parameters.

In some example embodiments, the apparatus further comprises: means for in response to the one or more currently configured parameters being disallowed to be updated, entering an idle mode from the inactive mode.

In some example embodiments, the apparatus further comprises: means for in response to the number of connection resume attempts initiated by updating the one or more currently configured parameters being above a threshold number, entering an idle mode from the inactive mode.

In some example embodiments, the apparatus further comprises: means for receiving, from the network device, an indication of the threshold number.

In some aspects, an apparatus comprises: means for determining an update pattern for one or more currently configured parameters to be used by a terminal device in an inactive mode to initiate a connection resume attempt; means for sending, to the terminal device, an indication of the update pattern for the one or more currently configured parameters; and means for detecting the connection resume attempt from the terminal device, using one or more updated parameters generated by updating the one or more parameters based on the update pattern.

In some example embodiments, the means for detecting the connection resume attempt comprises: means for detecting a connection resume request from the terminal device, using the one or more updated parameters.

In some example embodiments, the one or more currently configured parameters comprise a key for a bearer, and the apparatus further comprises: means for in response to completion of a connection resume procedure initiated by the terminal device with the connection resume request, transmitting, to the terminal device, an indication of a changed value of the key for the bearer.

In some example embodiments, the apparatus further comprises: means for transmitting, to the terminal device, an indication whether the one or more currently configured parameters is allowed to be updated.

In some example embodiments, the apparatus further comprises: means for transmitting, to the terminal device, an indication of a threshold number of connection resume attempts initiated by updating the one or more currently configured parameters.

In some aspects, a computer readable storage medium comprises program instructions stored thereon, the instructions, when executed by a processor of a device, causing the device to perform the method according to some example embodiments of the present disclosure.

Claims

A terminal device comprising:

at least one processor; and

at least one memory including computer program code;

the at least one memory and the computer program code configured to, with the at least one processor, cause the terminal device to:

obtain, in an inactive mode, one or more updated parameters by updating one or more currently configured parameters based on an update pattern; and

initiate, in the inactive mode, a connection resume attempt using the one or more updated parameters.
The terminal device of claim 1, wherein the terminal device is further caused to:

receive, from a network device, an indication of the update pattern.
The terminal device of claim 1 or 2, wherein the one or more updated parameters are obtained in response to at least one of:

arrival of non-small data transmission data during a small data transmission procedure;

cell reselection during the small data transmission procedure;

rejection of the small data transmission procedure;

expiry of a small data transmission failure timer; or

a radio link control entity reaching a configured maximum number of retransmissions.
The terminal device of any of claims 1-3, wherein the terminal device is caused to initiate the connection resume attempt using the one or more updated parameters by:

generating a connection resume request using the one or more updated parameters; and

initiating the connection resume attempt with the connection resume request.
The terminal device of claim 4, wherein the connection resume request contains resumeMAC-I generated based on the one or more updated parameters.
The terminal device of claim 4 or 5, wherein the terminal device is caused to initiate the connection resume attempt by:

initiating a connection resume procedure with the connection resume request to initiate the connection resume attempt.
The terminal device of claim 6, wherein the one or more currently configured parameters comprise a key for a bearer, and the terminal device is further caused to:

in response to completion of the connection resume procedure, receive, from the network device, an indication of a changed value of the key for the bearer.
The terminal device of claim 4 or 5, wherein the terminal device is caused to initiate the connection resume attempt by:

initiating a new small data transmission procedure with the connection resume request to initiate the connection resume attempt.
The terminal device of claim 8, wherein the one or more currently configured parameters comprise a count for the connection resume attempt, and the terminal device is further caused to:

update a count for a small data transmission data bearer using the update pattern.
The terminal device of any of claims 1-9, wherein the indication of the update pattern is received by the terminal device in a connected mode in a release message to release the terminal device from the connected mode to the inactive mode.
The terminal device of any of claims 1-10, wherein the update pattern comprises at least one of:

a step size to update a respective parameter of the one or more currently configured parameters;

an order to update the one or more currently configured parameters; or

identifications of the one or more currently configured parameters.
The terminal device of any of claims 1-11, wherein the terminal device is caused to obtain the one or more updated parameters by:

receiving, from the network device, an indication whether the one or more currently configured parameters is allowed to be updated; and

in response to the one or more currently configured parameters being allowed to be updated, updating the one or more currently configured parameters based on the update pattern to obtain the one or more updated parameters.
The terminal device of claim 12, wherein the terminal device is further caused to:

in response to the one or more currently configured parameters being disallowed to be updated, enter an idle mode from the inactive mode.
The terminal device of claim 12 or 13, wherein the indication whether the one or more currently configured parameters is allowed to be updated is received in a connection reject message.
The terminal device of any of claims 1-14, wherein the terminal device is further caused to:

in response to a number of connection resume attempts initiated by updating the one or more currently configured parameters being above a threshold number, enter an idle mode from the inactive mode.
The terminal device of claim 15, wherein the terminal device is further caused to:

receive, from the network device, an indication of the threshold number.
A network device comprising:

at least one processor; and

at least one memory including computer program code;

the at least one memory and the computer program code configured to, with the at least one processor, cause the network device to:

determine an update pattern for one or more currently configured parameters to be used by a terminal device in an inactive mode to initiate a connection resume attempt;

send, to the terminal device, an indication of the update pattern for the one or more currently configured parameters; and

detect the connection resume attempt from the terminal device, using one or more updated parameters generated by updating the one or more parameters based on the update pattern.
The network device of claim 17, wherein the network device is caused to detect the connection resume attempt by:

detecting a connection resume request from the terminal device, using the one or more updated parameters.
The network device of claim 18, wherein the connection resume request contains resumeMAC-I generated based on the one or more updated parameters.
The network device of claim 18 or 19, wherein the one or more currently configured parameters comprise a key for a bearer, and the network device is further caused to:

in response to completion of a connection resume procedure initiated by the terminal device with the connection resume request, transmit, to the terminal device, an indication of a changed value of the key for the bearer.
The network device of any of claims 17-20, wherein the update pattern comprises at least one of:

a step size to update a respective parameter of the one or more currently configured parameters;

an order to update the one or more currently configured parameters; or

identifications of the one or more currently configured parameters.
The network device of any of claims 17-21, wherein the network device is further caused to:

transmit, to the terminal device, an indication whether the one or more currently configured parameters is allowed to be updated.
The network device of claim 22, wherein the indication whether the one or more currently configured parameters is transmitted in a connection reject message.
The network device of any of claims 17-23, wherein the network device is further caused to:

transmit, to the terminal device, an indication of a threshold number of connection resume attempts initiated by updating the one or more currently configured parameters.
A method comprising:

obtaining, by a terminal device in an inactive mode, one or more updated parameters by updating one or more currently configured parameters based on an update pattern; and

initiating, by the terminal device in the inactive mode, a connection resume attempt using the one or more updated parameters.
The method of claim 25, further comprising:

receiving, from a network device, an indication of the update pattern.
The method of claim 25 or 26, wherein the one or more updated parameters are obtained in response to at least one of:

arrival of non-small data transmission data during a small data transmission procedure;

cell reselection during the small data transmission procedure;

rejection of the small data transmission procedure;

expiry of a small data transmission failure timer; or

a radio link control entity reaching a configured maximum number of retransmissions.
The method of claim any of claims 25-27, wherein initiating the connection resume attempt using the one or more updated parameters comprises:

generating a connection resume request using the one or more updated parameters; and

initiating the connection resume attempt with the connection resume request.
The method of claim 28, wherein the connection resume request contains resumeMAC-I generated based on the one or more updated parameters.
The method of claim 28 or 29, wherein initiating the connection resume attempt comprises:

initiating a connection resume procedure with the connection resume request to initiate the connection resume attempt.
The method of claim 30, wherein the one or more currently configured parameters comprise a key for a bearer, and the method further comprises:

in response to completion of the connection resume procedure, receiving, from the network device, an indication of a changed value of the key for the bearer.
The method of claim 28 or 29, wherein initiating the connection resume attempt comprises:

initiating a new small data transmission procedure with the connection resume request to initiate the connection resume attempt.
The method of claim 32, wherein the one or more currently configured parameters comprise a count for the connection resume attempt, and the method further comprises:

updating a count for a small data transmission data bearer using the update pattern.
The method of any of claims 26-33, wherein the indication of the update pattern is received by the terminal device in a connected mode in a release message to release the terminal device from the connected mode to the inactive mode.
The method of any of claims 26-34, wherein the update pattern comprises at least one of:

a step size to update a respective parameter of the one or more currently configured parameters;

an order to update the one or more currently configured parameters; or

identifications of the one or more currently configured parameters.
The method of any of claims 26-35, wherein obtaining the one or more updated parameters comprises:

receiving, from the network device, an indication whether the one or more currently configured parameters is allowed to be updated; and

in response to the one or more currently configured parameters being allowed to be updated, updating the one or more currently configured parameters based on the update pattern to obtain the one or more updated parameters.
The method of claim 36, further comprising:

in response to the one or more currently configured parameters being disallowed to be updated, entering an idle mode from the inactive mode.
The method of claim 36 or 37, wherein the indication whether the one or more currently configured parameters is allowed to be updated is received in a connection reject message.
The method of any of claims 26-38, further comprising:

in response to a number of connection resume attempts initiated by updating the one or more currently configured parameters being above a threshold number, entering an idle mode from the inactive mode.
The method of claim 39, further comprising:

receiving, from the network device, an indication of the threshold number.
A method comprising:

determining, by a network device, an update pattern for one or more currently configured parameters to be used by a terminal device in an inactive mode to initiate a connection resume attempt;

sending, by the network device to the terminal device, an indication of the update pattern for the one or more currently configured parameters; and

detecting, by the network device, the connection resume attempt from the terminal device, using one or more updated parameters generated by updating the one or more parameters based on the update pattern.
The method of claim 41, wherein detecting the connection resume attempt comprises:

detecting a connection resume request from the terminal device, using the one or more updated parameters.
The method of claim 42, wherein the connection resume request contains resumeMAC-I generated based on the one or more updated parameters.
The method of claim 42 or 43, wherein the one or more currently configured parameters comprise a key for a bearer, and the method further comprises:

in response to completion of a connection resume procedure initiated by the terminal device with the connection resume request, transmitting, to the terminal device, an indication of a changed value of the key for the bearer.
The method of any of claims 41-44, wherein the update pattern comprises at least one of:

a step size to update a respective parameter of the one or more currently configured parameters;

an order to update the one or more currently configured parameters; or

identifications of the one or more currently configured parameters.
The method of any of claims 41-45, further comprising:

transmitting, to the terminal device, an indication whether the one or more currently configured parameters is allowed to be updated.
The method of claim 46, wherein the indication whether the one or more currently configured parameters is transmitted in a connection reject message.
The method of any of claims 41-47, further comprising:

transmitting, to the terminal device, an indication of a threshold number of connection resume attempts initiated by updating the one or more currently configured parameters.
An apparatus, comprising:

means for obtaining, in an inactive mode, one or more updated parameters by updating one or more currently configured parameters based on an update pattern; and

means for initiating, in the inactive mode, a connection resume attempt using the one or more updated parameters.
An apparatus, comprising:

means for determining an update pattern for one or more currently configured parameters to be used by a terminal device in an inactive mode to initiate a connection resume attempt;

means for sending, to the terminal device, an indication of the update pattern for the one or more currently configured parameters; and

means for detecting the connection resume attempt from the terminal device, using one or more updated parameters generated by updating the one or more parameters based on the update pattern.
A computer readable storage medium comprising program instructions stored thereon, the instructions, when executed by a processor of a device, causing the device to perform the method of any of claims 25-40.
A computer readable storage medium comprising program instructions stored thereon, the instructions, when executed by a processor of a device, causing the device to perform the method of any of claims 41-48.