MOBILITY

CROSS-REFERENCE TO RELATED APPLICATION.

[0001] This application claims priority from U.S. Provisional Patent Application No. 62/062535 filed October 10, 2014, which is hereby incorporated in its entirety.

TECHNICAL FIELD

[0002] The present application relates generally to interworking optimization during cellular mobility.

BACKGROUND

[0003] Various communication systems may benefit from optimizations related to mobility. For example, radio access network assisted, third generation partnership project and wireless local area network interworking may benefit from various optimizations for cellular mobility.

[0004] For radio access network (RAN) assisted wireless local area network (WLAN), interworking RAN assistance parameters can be provided in broadcast or dedicated signaling. Dedicated RAN assistance parameters can be kept by the user equipment (UE) when moving from RRC CONNECTED to RRC IDLE until a timer, T350, expires/stops or the UE performs cell (re)selection.

[0005] Based on the above, the following scenario may occur. The UE can be in connected state with active traffic transfer on the cellular cell A and in coverage area of the WLAN access point (AP) with identifier X. The network (NW) can decide to configure dedicated RAN- assisted WLAN interworking RAN assistance parameters for the UE, because the UE generates a lot of traffic. These parameters can be valid for WLAN AP with identifier X. The UE can determine based on the configured RAN-assisted WLAN interworking RAN assistance parameters that the traffic is to be steered to the WLAN AP with identifier X. Thus, the UE can steer the traffic to the WLAN AP with identifier X. The radio resource control (RRC) connection can be released and the UE can enter IDLE state e.g. since there is no more active data transfer between UE and NW, because the traffic was steered to WLAN.

[0006] However, after a while the UE may perform cell reselection to cellular Cell B. This may be, for example, due to UE geographical movement which would cause the change in radio condition the UE is experiencing and which may result that the cell reselection criteria is fulfilled. Accordingly, dedicated RAN assistance parameters may be deleted by the UE, because cell re-selection happened.

[0007] Meanwhile, Cell B may be broadcasting RAN-assisted WLAN interworking RAN assistance parameters. It may be that, according to those parameters, the traffic is to be steered to cellular.

[0008] Thus, the UE can determine that the traffic is to be steered to the cellular from WLAN AP with identifier X. The connection can be established on cellular cell B and the UE can steer the traffic to the cellular

[0009] Then, the NW can decide to configure dedicated RAN-assisted WLAN interworking RAN assistance parameters for the UE, because the UE generates a lot of traffic. These parameters may be valid for WLAN AP with identifier X. Accordingly, the UE can determine that the traffic is to be steered to the WLAN AP with identifier X and the UE can steer the traffic to the WLAN AP with identifier X. This ping pong between WLAN and cellular may occur frequently.

[00010] It is up to a network implementation to decide when the network configures the dedicated parameters for the UE. The network could make the decision, for example, based on the cell load, load in the WLAN, core network load, subscriber class such as gold, silver, or bronze, based on what kind traffic is ongoing with the UE, based on amount of traffic, or the like.

[00011] Additionally, in idle mode the following scenario can occur. The UE can have valid WLAN offloading parameters. The UE can then evaluate neighbor cell and can make reselection. Accordingly, following conventional rules, the UE can delete WLAN offload parameters. The UE can read SIB 17, or a system information block (SIB) containing WLAN offloading parameters, and can again have valid parameters.

[0010] During the time between deleting offloading parameters and reading SIB 17, the UE does not have valid information and ping pong may occur.

[0011] In the conventional approach it is the case that the UE is supposed to delete dedicated RAN assistance parameters in connection with cellular cell reselection, so that there can be cell specific RAN assistance parameters. Thus, each eNb can be responsible for configuring the parameters. The eNb may want to configure the RAN assistance parameters based on the eNb' s own load situation, as opposed to that of any other cell or of the network as a whole.

[0012] 3GPP has described 3GPP / WLAN interworking in 3GPP TR 22.934, TS 24.234, and TS 36.300 (e.g. section 23.6), all of which are hereby incorporated by reference in their entirety. Moreover, 3GPP has described dedicated WLAN offload in TS36.331 (e.g. section 5.6.12) and access procedures with respect to idle mode in TS36.304 (e.g. section 5.6), both of which are hereby incorporated by reference in their entirety.

SUMMARY OF THE INVENTION

[0013] Various aspects of examples of the invention are set out in the claims.

[0014] According to a first aspect of the present invention, a method for determining how a user equipment is to use radio access network assistance parameters in connection with at least one of cell selection, reselection, handover, or radio resource control connection (re)establishment; and for signaling in accordance with the determining an indication to the user equipment how the user equipment is to use the radio access network assistance parameters in connection with at least one of cell selection, reselection, handover, or radio resource control connection (re)establishment.

[0015] According to a second aspect of the present invention, a method for determining whether an indication has been received at a user equipment indicating how the user equipment is to use radio access network assistance parameters in connection with at least one of cell selection, reselection, handover, or radio resource control connection establishment; if the indication has been received, following the indication; and if the indication has not been received, deleting the parameters.

[0016] According to a third aspect of the present invention, a method for determining in connection with at least one of cell selection, reselection, handover, or radio resource control connection establishment whether radio access network assistance parameters obtained prior to the at least one cell selection, reselection, handover, or radio resource control connection establishment have been updated or whether the cell selected to, reselected to, handed over to, or to which a radio resource control connection is being established does not broadcast a new set of radio access network assistance parameters; and in dependence of the determining, maintaining (650) the radio access network assistance parameters.

[0017] According to a fourth aspect of the present invention, an apparatus comprising means for performing the methods according to the first, second or third aspect.

[0018] According to a fifth aspect of the present invention, a computer program or computer program product for performing the methods according to the first second or third aspect.

[0019] According to a sixth aspect of the present invention, an apparatus 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 apparatus to perform at least the following: determine how a user equipment is to use radio access network assistance parameters in connection with at least one of cell selection, reselection, handover, or radio resource control connection (re)establishment; signal in accordance with the determining an indication to the user equipment how the user equipment is to use the radio access network assistance parameters in connection with at least one of cell selection, reselection, handover, or radio resource control connection (re)establishment.

[0020] According to a seventh aspect of the present invention, an apparatus 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 apparatus to perform at least the following: determine in connection with at least one of cell selection, reselection, handover, or radio resource control connection establishment whether radio access network assistance parameters obtained prior to the at least one cell selection, reselection, handover, or radio resource control connection establishment have been updated or whether the cell selected to, reselected to, handed over to, or to which a radio resource control connection is being established does not broadcast a new set of radio access network assistance parameters; and in dependence of the determining, maintaining the radio access network assistance parameters.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] For proper understanding of the invention, reference should be made to the accompanying drawings, wherein:

[0022] Figure 1 illustrates a signaling flow according to certain embodiments.

[0023] Figure 2 illustrates a method according to certain embodiments.

[0024] Figure 3 illustrates another method according to certain embodiments.

[0025] Figure 4 illustrates a further method according to certain embodiments.

[0026] Figure 5 illustrates a system according to certain embodiments.

[0027] Figure 6 illustrates a further method according to certain embodiments.

DETAILED DESCRIPTON

[0028] According to certain embodiments, an information/indication can be provided in dedicated and /or broadcast signaling to the user equipment (UE) as to what the UE is supposed to do with radio access network (RAN) assistance parameters in connection with cell selection and/or reselection and/or handover and/or RRC connection establishment. [0029] The information may, for example, be any of the following: keep parameters; delete parameters; suspend parameters (for example, deactivate usage of parameters until expiration of a timer or until cell reselection, selection, connection (re)establishment occurs); use broadcasted parameters in IDLE mode; or use dedicated parameters in IDLE mode.

[0030] The information can also include a list of cell(s) for which the information is valid. Based on this, the UE, may be configured not to delete the parameters when camping/reselecting/selecting/handed over on these cells included in the list.

[0031] There could also or alternatively be other information, such as CGI, ECGI, PLMN, carrier, frequency, and/or RAU/TAU/LAU, which describes where the information is valid i.e. information is valid in signaled CGI (Cell Global Identity), PCI (Physical Cell Identity) ECGI (Enhanced CGI), PLMN, carrier, frequency, and/or RA (Routing Area)/TA(Tracking Area)/LA(Location Area).

[0032] If no (above) information is signaled, in certain embodiments the UE can be configured to delete parameters

[0033] In certain embodiments, a rule can be defined that the UE is to keep WLAN parameters until the UE knows that the WLAN parameters have been updated or the UE knows that cell does or does not broadcast a new set of parameters. Thus, the UE may not initiate WLAN offloading changes, for example move data from WLAN to EUTRAN, until reception of WLAN parameters.

[0034] Similar rules as discussed above could also or alternatively be used. For example, there can be an indication for the UE as to what to do with WLAN offloading parameters at a point of reselection.

[0035] Signaling of the indication or information can be done in a variety of ways. For example, the following examples provide an illustration of how the signaling may be utilized by the UE and NW.

[0036] Figure 1 illustrates a signaling flow according to certain embodiments. As shown in Figure 1, at 110 initially, the UE may be in connected state with active traffic transfer on the cellular cell A and in coverage area of the WLAN AP with identifier X. The NW can decide to, at 120, configure dedicated RAN-assisted WLAN interworking RAN assistance parameters for the UE. This decision may be, for example, because the UE generates a lot of traffic.

[0037] The parameters may be valid for WLAN AP with identifier X. Moreover, the UE may be configured to keep the parameters in cell reselection to Cells A, B and C.

[0038] The UE can determine that the traffic is to be steered to the WLAN AP with identifier X. Thus, the UE can, at 130, steer the traffic to the WLAN AP with identifier X. When there is no more active data transfer between UE and NW the RRC connection can, at 140 be released and the UE can enter IDLE state.

[0039] After a while, at 150 the UE can perform cell reselection to cellular Cell B, for example due to UE geographical movement which may fulfill the cell reselection criteria.

[0040] Dedicated RAN assistance parameters may not be deleted by the UE, simply because cell re-selection happened to Cell B. Cell B may be, AT 160, broadcasting RAN-assisted WLAN interworking RAN assistance parameters, but the UE can keep the dedicated parameters AT 170. According to the dedicated parameters, the traffic can be kept in WLAN. Thus, data transfer can continue in WLAN and ping pong between WLAN and cellular can be avoided.

[0041] Figure 2 illustrates a method according to certain embodiments. As shown in Figure 2, a method include, at 210, determining how a user equipment is to use radio access network assistance parameters in connection with at least one of cell selection, reselection, handover, or radio resource control connection establishment. The method can also include, at 220, preparing an indication to the user equipment how the user equipment is to use radio access network assistance parameters in connection with at least one of cell selection, reselection, handover, or radio resource control connection establishment.

[0042] The method can further include, at 230, signaling the indication to the user equipment in at least one of dedicated signaling or broadcast signaling. The indication can include at least one of keep the parameters, delete the parameters, suspend the parameters, use broadcasted parameters in IDLE mode, or use dedicated parameters in IDLE mode. The indication can further include a list of at least one cell for which the indication is valid. Indication can further include information indicating where parameters can or cannot be used: PCI, CGI, ECGI, PLMN, carrier, frequency, and/or RAU/TAU/LAU.

[0043] Figure 3 illustrates another method according to certain embodiments. As shown in Figure 3, at 310 the method can include determining whether an indication has been received at a user equipment regarding how the user equipment is to use radio access network assistance parameters in connection with at least one of cell selection, reselection, handover, or radio resource control connection (re)establishment. The method can further include, at 320, following the indication if the indication was received. The method can additionally include, at 330, deleting the parameters if the indication was not received.

[0044] Figure 4 illustrates a further method according to certain embodiments. As shown in Figure 4, at 410 a method can include keeping wireless local area network parameters. The method can also include, at 420, deleting the parameters conditioned on determining that the wireless local area network parameters have been updated or determining that a cell does not broadcast a new set of wireless local area network parameters. At 430, the method can further include initiating a wireless local area network offloading change conditioned on reception of new wireless local area network parameters.

[0045] Figure 5 illustrates a system according to certain embodiments of the invention. It should be understood that each block of the flowchart of any of Figures 1 through 4 may be implemented by various means or their combinations, such as hardware, software, firmware, one or more processors and/or circuitry. In one embodiment, a system may include several devices, such as, for example, network element 510 and user equipment (UE) or user device 520. The system may include more than one UE 520 and more than one network element 510, although only one of each is shown for the purposes of illustration. A network element can be an access point, a base station, an eNode B (eNB), an access point, or any other network element. Each of these devices may include at least one processor or control unit or module, respectively indicated as 514 and 524. At least one memory may be provided in each device, and indicated as 515 and 525, respectively. The memory may include computer program instructions or computer code contained therein. One or more transceiver 516 and 526 may be provided, and each device may also include an antenna, respectively illustrated as 517 and 527. Although only one antenna each is shown, many antennas and multiple antenna elements may be provided to each of the devices. For example, a two-dimensional array of antenna elements may be used by network element 510. Other configurations of these devices, for example, may be provided. For example, network element 510 and UE 520 may be additionally configured for wired communication, in addition to wireless communication, and in such a case antennas 517 and 527 may illustrate any form of communication hardware, without being limited to merely an antenna.

[0046] Transceivers 516 and 526 may each, independently, be a transmitter, a receiver, or both a transmitter and a receiver, or a unit or device that may be configured both for transmission and reception. The transmitter and/or receiver (as far as radio parts are concerned) may also be implemented as a remote radio head which is not located in the device itself, but in a mast, for example. It should also be appreciated that according to the "liquid" or flexible radio concept, the operations and functionalities may be performed in different entities, such as nodes, hosts or servers, in a flexible manner. In other words, division of labor may vary case by case. One possible use is to make a network element to deliver local content. One or more functionalities may also be implemented as a virtual application that is as software that can run on a server. [0047] A user device or user equipment 520 may be a mobile station (MS) such as a mobile phone or smart phone or multimedia device, a computer, such as a tablet, provided with wireless communication capabilities, personal data or digital assistant (PDA) provided with wireless communication capabilities, portable media player, digital camera, pocket video camera, navigation unit provided with wireless communication capabilities or any combinations thereof. The user device or user equipment 520 may be a sensor or smart meter, or other device that may usually be configured for a single location.

[0048] In an exemplifying embodiment, an apparatus, such as a node or user device, may include means for carrying out embodiments described above in relation to any of Figures 1 through 4.

[0049] Processors 514 and 524 may be embodied by any computational or data processing device, such as a central processing unit (CPU), digital signal processor (DSP), application specific integrated circuit (ASIC), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), digitally enhanced circuits, or comparable device or a combination thereof. The processors may be implemented as a single controller, or a plurality of controllers or processors. Additionally, the processors may be implemented as a pool of processors in a local configuration, in a cloud configuration, or in a combination thereof.

[0050] For firmware or software, the implementation may include modules or unit of at least one chip set (e.g., procedures, functions, and so on). Memories 515 and 525 may independently be any suitable storage device, such as a non-transitory computer-readable medium. A hard disk drive (HDD), random access memory (RAM), flash memory, or other suitable memory may be used. The memories may be combined on a single integrated circuit as the processor, or may be separate therefrom. Furthermore, the computer program instructions may be stored in the memory and which may be processed by the processors can be any suitable form of computer program code, for example, a compiled or interpreted computer program written in any suitable programming language. The memory or data storage entity is typically internal but may also be external or a combination thereof, such as in the case when additional memory capacity is obtained from a service provider. The memory may be fixed or removable.

[0051] The memory and the computer program instructions may be configured, with the processor for the particular device, to cause a hardware apparatus such as network element 510 and/or UE 520, to perform any of the processes described above (see, for example, any of Figures 1 through 4). Therefore, in certain embodiments, a non-transitory computer- readable medium may be encoded with computer instructions or one or more computer program (such as added or updated software routine, applet or macro) that, when executed in hardware, may perform a process such as one of the processes described herein. Computer programs may be coded by a programming language, which may be a high-level programming language, such as objective-C, C, C++, C#, Java, etc., or a low-level programming language, such as a machine language, or assembler. Alternatively, certain embodiments of the invention may be performed entirely in hardware.

[0052] Furthermore, although Figure 5 illustrates a system including a network element 510 and a UE 520, embodiments of the invention may be applicable to other configurations, and configurations involving additional elements, as illustrated and discussed herein. For example, multiple user equipment devices and multiple network elements may be present, or other nodes providing similar functionality, such as nodes that combine the functionality of a user equipment and an access point, such as a relay node.

[0053] Figure 6 illustrates a signaling flow according to certain embodiments. As shown in Figure 6, a UE receives (610) radio access network assistance parameters and performs (620) one of a selection, reselection, handover, or radio resource control connection establishment to a new cell. The UE then checks whether the radio access network assistance parameters are updated (630) by the new cell and/or whether the new cell broadcasts (640) new/updated radio access network assistance parameters. If not, the UE may maintain (650) the radio access network parameters and prevent (660) an initiation of a change to an offloading. Once the radio access network assistance parameters are updated and/or the UE determines that the cell does not broadcast net radio access network assistance parameters, the UE may initiate or allow initiation of a change to the offloading.

[0054] Certain embodiments may have various benefits and/or advantages. For example, in certain embodiments the network can choose how the user equipment is to handle the WLAN interworking parameters. Moreover, in certain embodiments, ping pong between WLAN and cellular can be reduced. Furthermore, in certain embodiments user experience can be improved.

[0055] Although in the preceding discussion, WLAN parameters are used as an example, various embodiments are not limited to cases involving WLAN parameters, but can be applied to other similar scenarios. Thus, whatever parameters are provided with dedicated and / or broadcast signaling can be handled in the same way as described above for WLAN interworking parameters.

[0056] One having ordinary skill in the art will readily understand that the invention as discussed above may be practiced with steps in a different order, and/or with hardware elements in configurations which are different than those which are disclosed. Therefore, although the invention has been described based upon these preferred embodiments, it would be apparent to those of skill in the art that certain modifications, variations, and alternative constructions would be apparent, while remaining within the spirit and scope of the invention.

[0057] List of Abbreviations

[0058] UE user equipment

[0059] eNB enhanced NodeB or evolved Node B

[0060] RRC radio resource control

[0061] SI system information

[0062] CGI cell global identity

[0063] ECGI E-UTRAN CGI

[0064] PLMN public land mobile network

[0065] RAU routing area update

[0066] TAU tracking area update

[0067] LAU location area update

[0068] UMTS universal mobile telecommunications system

[0069] UTRAN UMTS terrestrial radio access network

[0070] According to a first embodiment, a method can include determining how a user equipment is to use radio access network assistance parameters in connection with at least one of cell selection, reselection, handover, or radio resource control connection (re)establishment. The method can also include preparing an indication to the user equipment how the user equipment is to use radio access network assistance parameters in connection with at least one of cell selection, reselection, handover, or radio resource control connection (re)establishment.

[0071] In a variant, the method can further include signaling the indication to the user equipment in at least one of dedicated signaling or broadcast signaling.

[0072] In a variant, the indication can include at least one of keep the parameters, delete the parameters, suspend the parameters, use broadcasted parameters in IDLE mode, or use dedicated parameters in IDLE mode.

[0073] In a variant, the indication can include a list of at least one cell for which the indication is valid.

[0074] According to a second embodiment, a method can include determining whether an indication has been received at a user equipment regarding how the user equipment is to use radio access network assistance parameters in connection with at least one of cell selection, reselection, handover, or radio resource control connection establishment. The method can also include following the indication if the indication was received. The method can further include deleting the parameters if the indication was not received.

[0075] The second embodiment may have the same or similar variants to the first embodiment.

[0076] According to a third embodiment, a method can include keeping wireless local area network parameters. The method can include deleting the parameters conditioned on determining that the wireless local area network parameters have been updated or determining that a cell does not broadcast a new set of wireless local area network parameters.

[0077] In a variant, the method can further include initiating a wireless local area network offloading change conditioned on reception of new wireless local area network parameters.

[0078] According to fourth through sixth embodiments, an apparatus can include means for performing a respective method of the first through third embodiments.

[0079] According to seventh through ninth embodiments, an apparatus can include at least one processor and at least one memory including computer program code. The at least one memory and the computer program code can be configured to, with the at least one processor perform a respective method of the first through third methods.

[0080] According to tenth through twelfth embodiments, a computer program product can encode instructions for performing a process. The process can correspond to the method of any of the first through third methods.

[0081] According to thirteenth through fifteenth embodiments, a non-transitory computer- readable medium can be encoded with instructions that, when executed in hardware, perform a process. The process can correspond to the method of any of the first through third embodiments.