Abstract:
A wireless communication device communicates with a GPRS wireless network where ciphering has gone out of sync between the wireless communication device and the wireless network. The wireless communication device triggers an authentication procedure that re-synchronizes the ciphering. Following the trigger, the wireless communication device and the wireless network continue the authentication procedure so that ciphering parameters can be negotiated again and data communication can resume.

Description:
TECHNICAL FIELD 
       [0001]    Embodiments herein relate to a method performed by a wireless communication device when communicating with a general packet radio service (GPRS) wireless network. 
       BACKGROUND 
       [0002]    In a wireless network such as a third generation partnership project (3GPP) GPRS wireless network that operates according to a global system for mobile communications (GSM) standard ciphering of packet service (PS) data is performed in a logical link control (LLC) layer. Ciphering parameters that are needed for the ciphering to operate are negotiated between wireless communication devices and a network by a GPRS mobility management (GMM) entity. A GMM entity is a functional block that has an interface to a lower LLC layer in the communication protocol stack. 
         [0003]    Due to various disturbing effects on radio signals carrying the enciphered data along a radio path of an uplink and/or downlink between a wireless communication device and the wireless network, the ciphering may get unsynchronized. That is, data that has been enciphered at the wireless communication device cannot be deciphered at a receiving network node, and vice versa. When this occurs, neither the wireless communication device, nor the network node is able to receive anything successfully. This typically leads to a data connection between the entities being aborted and the wireless communication device enters an idle state. If this situation occurs during a GMM routing area update procedure, then it is a severe drawback since the wireless communication device is in such a situation not able to register itself in a packet domain. For example, this will lead to a permanent packet service (PS) registration failure as the wireless communication device will never be able to receive routing area update accept messages in a downlink direction and, as a consequence, the wireless communication device will keep on retransmitting routing area update requests. This issue can be seen in case of buggy networks and in an IRAT scenario where a wireless communication device moves from, e.g., a third or fourth generation radio network to a GPRS network. Sometimes in such scenarios a wireless communication device is not able to get a correct ciphering key and it is thereby not able to decipher received enciphered downlink data and hence it will be unable to register successfully in the GPRS network. 
         [0004]    In United States patent application publication US2004/0053623 problems with unsynchronized ciphering parameters are discussed. Ciphering is re-synchronized by way of specific LLC signaling between a mobile station and a serving GPRS support node. 
       SUMMARY 
       [0005]    In order to at least mitigate at least some of the drawbacks as discussed above, different aspects and embodiments are provided in the present disclosure. 
         [0006]    One aspect provides a method performed by a wireless communication device when communicating with a GPRS wireless network. The method comprises:
       receiving, in a LLC entity in the wireless communication device, enciphered downlink data from a LLC entity in the wireless network,   determining, in the LLC entity in the wireless communication device, that the enciphered downlink data cannot be deciphered,   providing, from the LLC entity in the wireless communication device as a consequence of the determination that the enciphered downlink data cannot be deciphered, a ciphering failure indicator to a GMM entity in the wireless communication device,   receiving, in the GMM entity in the wireless communication device, the ciphering failure indicator and, as a consequence of the reception of the ciphering failure indicator in the GMM entity in the wireless communication device, providing an authentication procedure trigger from the GMM entity in the wireless communication device to a GMM entity in the wireless network, and   operating an authentication procedure wherein the GMM entity in the wireless communication device communicates with a GMM entity in the wireless network via the respective LLC entities in the wireless communication device and the wireless network, whereby the LLC entity in the wireless communication device obtains information for enabling enciphering and deciphering in subsequent communication between the LLC entity in the wireless communication device and the LLC entity in the wireless network.       
 
         [0012]    In some embodiments, the provision of an authentication procedure trigger from the GMM entity in the wireless communication device to a GMM entity in the wireless network may comprise transmitting any of a routing area update request message and an attach request message that comprises a ciphering key sequence number (CKSN) information element having a value of 7. 
         [0013]    In some embodiments, the GMM entity in the wireless communication device receives a CKSN in a GMM authentication and ciphering request message. The received CKSN identifies a security context that comprises a security key. 
         [0014]    In some embodiments, the security key is obtained in the GMM entity in the wireless communication device from the security context identified by the received CKSN. In these embodiments, the obtaining of the information for enabling enciphering and deciphering in subsequent communication between the LLC entity in the wireless communication device and the LLC entity in the wireless network comprises receiving, in the LLC entity in the wireless communication device, the security key from the GMM entity in the wireless communication device. 
         [0015]    In other words, drawbacks are mitigated in a situation where ciphering has gone out of sync between the wireless communication device and the wireless network. The wireless communication device triggers an authentication procedure that re-synchronizes the ciphering, for example by transmitting a CKSN with a value “7” in a routing area update or attach request message to the wireless network. On such a request, the wireless communication device and the wireless network continue the authentication procedure so that ciphering parameters can be negotiated again and data communication can resume. 
         [0016]    Further aspects provide a wireless communication device, a computer program and a carrier comprising such computer program that correspond to the aspect as summarized above. The effects and advantages of these further aspects correspond to those summarized above in connection with the method performed by the wireless communication device. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]      FIG. 1  schematically illustrates a wireless network  100 , 
           [0018]      FIG. 2 a    schematically illustrates communication protocol stacks, 
           [0019]      FIG. 2 b    schematically illustrates functional entities associated with the communication protocol stacks in  FIG. 2   a,    
           [0020]      FIG. 3  is a flowchart of a method in a wireless communication device, 
           [0021]      FIG. 4  is a flowchart of a method in a wireless communication device, 
           [0022]      FIG. 5  is a signalling diagram that is associated with the flowchart in  FIG. 4 , 
           [0023]      FIG. 6  schematically illustrates a block diagram of a wireless communication device, and 
           [0024]      FIG. 7  schematically illustrates a block diagram of a wireless communication device. 
       
    
    
     DETAILED DESCRIPTION 
       [0025]      FIG. 1  illustrates schematically an exemplifying wireless network  100  in which embodiments herein may be implemented. The wireless network  100  may be any 3GPP wireless network, such as a Universal Mobile Telecommunication System (UMTS) Wideband Code Division Multiple Access (WCDMA) network, a Global System for Mobile communication (GSM), or the like. The wireless communication system  100  may be an evolution of any one of the aforementioned systems or a combination thereof, including a Long Term Evolution (LTE) wireless network. 
         [0026]    The wireless network  100  may comprise a number of different nodes distributed in a radio access network  102  and a core network  103 . 
         [0027]    Nodes in the wireless network  100  may be denoted “network node” and, for example, refer to a Base Station (BS), a Base Transceiver Station (BTS), a Radio Base Station (RBS), a Remote Radio Unit (RRU), an access point, a NodeB in 3G networks, evolved NodeB (eNodeB or eNB) in LTE networks, or the like. In UMTS Terrestrial Radio Access Network (UTRAN) networks, a node may also be a Radio Network Controller (RNC). Furthermore, in GSM EDGE Radio Access Network, GERAN, where EDGE is short for Enhanced Data rates for GSM Evolution, the term “network node” may also refer to a Base Station Controller (BSC). 
         [0028]    As  FIG. 1  shows, a node  104  may be connected to other nodes in the system, exemplified here by a node  105  in the radio access network  102  and further connected to a node  107 , which may represent any entity in the core network  103  and further nodes, such as node  110  in another network  109 . It is to be noted, however, that any details regarding communication with such entities is outside the scope of the present disclosure. 
         [0029]    A number of wireless communication devices (WCD) may be operating in connection with the wireless network  100 . One such wireless communication device  106  is shown being in connection with the wireless network  100  via a radio interface  111  with the node  104  in the radio access network  102 . The wireless communication device  106  and typically many other wireless communication devices are located in cells (not illustrated) that are under the control of, e.g., a base station, which may be represented by the node  104 . 
         [0030]    In the following description of methods performed by a wireless communication device, communication will take place between a wireless communication device and a network node, which may be a serving GPRS support node (SGSN) represented by node  107  in  FIG. 1 . The nodes  104  and  105  in  FIG. 1  may in such examples be a base transceiver station (BTS) and a base station controller (BSC), respectively. 
         [0031]    As used herein, the term “wireless communication device” may refer to a user equipment (UE), a subscriber unit, mobile station (MS) mobile phone, a cellular phone, a Personal Digital Assistant (PDA), equipped with radio communication capabilities, a smartphone, a laptop or personal computer (PC), equipped with an internal or external mobile broadband modem, a tablet PC with radio communication capabilities, a portable electronic radio communication device or the like. As will be described in some detail in the following, focus will be made on communication between the wireless communication device  106  and a network node such as the base station  104 . 
         [0032]    In  FIG. 2 a   , communication protocol stacks  201 ,  203  in a wireless communication device and in a network node, respectively, are schematically illustrated. The wireless communication device in  FIG. 2 a    may correspond to the wireless communication device  106  in  FIG. 1  and the network node in  FIG. 2 a    may correspond to the network node  107  (e.g. a SGSN) in  FIG. 1 . At lowest levels or layers  219 ,  239  communication  203  takes place via a radio interface such as the radio interface  111  illustrated in  FIG. 1 , details of which are outside the scope of the present disclosure. Higher levels  217 ,  237  of the communication protocol stacks are also involved in the communication between the wireless communication device and, as for the lower layers  219 ,  239  the details regarding this communication are outside the scope of the present disclosure. 
         [0033]    Communication between LLC layers  215 ,  235  involves a respective LLC entity  216 ,  236  in the wireless communication device and the network node, respectively. Above the LLC layers  215 ,  235  are a number of communication entities such as GPRS mobility management (GMM)  209 ,  229  and user data handling entities  213 ,  233  handling user data to and from respective user applications  205 ,  225 . As  FIG. 2 a    shows, the user applications  205 ,  225  communicate via further intermediate layers  207 ,  217  including, e.g., an internet protocol (IP) layer. 
         [0034]      FIG. 2 b    is a more detailed view, although still schematically illustrated, of the LLC entity  216  in the wireless communication device in  FIG. 2 a   .  FIG. 2 b    illustrates that GMM data  251  is provided by the GMM entity  209  to a logical link entity (LLE)  257  having a service access point identifier (SAPI) that is equal to 1. Similarly, the user data handling entity  213  provides user data  253  to any of a number of LLEs with SAPI equal to 3, 5, 7 or 9, one of which, LLE having a SAPI equal to 9, is referenced by reference numeral  259 . User data in the form of short message service (SMS) data  255  is provided by the user data handling entity  213  to a LLE having a SAPI equal to 7. 
         [0035]    The entities illustrated in  FIG. 2 b    are to be understood as function blocks that are implemented by a combination of hardware circuits and controlling software, e.g. in the form of separate processes in an operating system. The entity  216  represents different LLE entities that offer various services to higher layer protocol to exchange information with its peer entities in the network node. The entity  257  is used to send/receive the enciphered/de-cipher the GMM data. The entity  261  is used to exchange the SMS data. The entity  259  is dedicated to encipher/decipher the user data. 
         [0036]    Turning now to  FIG. 3 , a method will be described in terms of a number of actions performed by a wireless communication device such as the wireless communication device  106  illustrated in  FIG. 1 , which operates by means of an LLC entity and a GMM entity such as the LLC entity  216  and GMM entity  209  in  FIGS. 2 a  and 2 b   . The communication takes place in connection with an LLC entity and a GMM entity, such as the LLC and GMM entities  236  and  229  in  FIG. 2 a   , in a wireless network such as the wireless network  100  in  FIG. 1 . In the example of  FIG. 3 , the wireless network is in the form of a GPRS wireless network. Implementation in other types of networks will involve use of corresponding entities, as the skilled person will realize. 
         [0037]    As illustrated in  FIG. 3 , the method performed by the wireless communication device when communicating with a GPRS wireless network comprises actions as follows: 
         [0038]    Action  301   
         [0039]    Enciphered downlink data is received in a LLC entity in the wireless communication device from a LLC entity in the wireless network. 
         [0040]    Action  303   
         [0041]    A determination is made in the LLC entity in the wireless communication device, that the enciphered downlink data cannot be deciphered. 
         [0042]    In some embodiments, the reception in action  301  of enciphered downlink data may comprise reception of enciphered GMM data via a LLE having a SAPI equal to 1. In these embodiments, the determination that the enciphered downlink data cannot be deciphered may comprise a determination of a first predetermined number of cyclic redundancy check, CRC, failures associated with the received enciphered GMM data. 
         [0043]    In some embodiments, the reception of enciphered downlink data may comprise reception of enciphered user data via a LLE having a SAPI equal to any of 3, 5, 7, 9 and 11. In these embodiments, the determination that the enciphered downlink data cannot be deciphered may comprise a determination of a second predetermined number of CRC failures associated with the received enciphered user data. For example, the second predetermined number of CRC failures associated with the received enciphered user data may be greater than the first predetermined number of CRC failures associated with the received enciphered GMM data. 
         [0044]    Action  305   
         [0045]    As a consequence of the determination that the enciphered downlink data cannot be deciphered, a ciphering failure indicator is provided from the LLC entity in the wireless communication device to a GMM entity in the wireless communication device. 
         [0046]    Actions  307  and  309   
         [0047]    The ciphering failure indicator is received in the GMM entity in the wireless communication device and as a consequence of the reception of this ciphering failure indicator in the GMM entity in the wireless communication device, an authentication procedure trigger is provided from the GMM entity in the wireless communication device to a GMM entity in the wireless network. 
         [0048]    In some embodiments, the provision of an authentication procedure trigger from the GMM entity in the wireless communication device to the GMM entity in the wireless network may comprise transmitting any of a routing area update request message and an attach request message that comprises a CKSN information element having a value of 7. 
         [0049]    Action  311   
         [0050]    An authentication procedure is operated wherein the GMM entity in the wireless communication device communicates with the GMM entity in the wireless network via the respective LLC entities in the wireless communication device and the wireless network, whereby the LLC entity in the wireless communication device obtains information for enabling enciphering and deciphering in subsequent communication between the LLC entity in the wireless communication device and the LLC entity in the wireless network. For example, the GMM entity in the wireless communication device may receive a CKSN in a GMM authentication and ciphering request message. The received CKSN identifies a security context that comprises a security key. In some of these examples, the security key may be obtained in the GMM entity from the security context identified by the received CKSN. Then, the obtaining of the information for enabling enciphering and deciphering in subsequent communication between the LLC entity in the wireless communication device and the LLC entity in the wireless network comprises receiving, in the LLC entity in the wireless communication device, the security key from the GMM entity in the wireless communication device. 
         [0051]    Turning now to  FIG. 4  and  FIG. 5  and with continued reference to  FIGS. 1, 2   a  and  2   b , further embodiments of a method performed by a wireless communication device when communicating with a GPRS wireless network will be described. Similar to the embodiments described above in connection with  FIGS. 1 to 3 , the embodiments will be described in terms of a number of actions performed by a wireless communication device  506 , which may correspond to the wireless communication device  106  illustrated in  FIG. 1 . In  FIG. 5 , the wireless communication device  506  is denoted UE. The wireless communication device  506  operates by means of an LLC entity  522  and a GMM entity  521  such as the LLC entity  216  and GMM entity  209  in  FIGS. 2 a  and 2 b   . As discussed above, the LLC entity  522  and a GMM entity  521  in the wireless communication device  506  may be realized by means of separate processes in an operating system. 
         [0052]    The communication takes place in connection with an LLC entity  531  and a GMM entity  532  in a wireless network node  530 , such as the LLC and GMM entities  236  and  229  in  FIG. 2 a   , which may be comprised in any of the nodes  104 ,  105  in the wireless network  100  in  FIG. 1 . Similar to the embodiments described above, in the example of  FIG. 5 , the wireless network is in the form of a GPRS wireless network. Implementation in other types of networks will involve use of corresponding entities, as the skilled person will realize. 
         [0053]    Action  401   
         [0054]    Enciphered downlink data  550  is received in the LLC entity  522  in the wireless communication device  506  from the LLC entity  531  in the network node  530 . The downlink data  550  may be any GMM data as well as user data from user applications and SMS data that are received via LLEs having SAPI=1, 3, 5, 7, 9, or 11 as discussed above. 
         [0055]    Action  403   
         [0056]    A CRC is made on the received downlink data  550 . 
         [0057]    Action  405   
         [0058]    A determination is made whether or not the CRC in action  403  failed. 
         [0059]    Action  407   
         [0060]    A check is made whether or not a CRC failure has occurred less than a predetermined number of times (denoted N in  FIG. 4 ). According to this check, the determination in action  405  may be performed a number of times N, where the value of N may depend on the reception of the downlink data. If a CRC failure has occurred less than N times, reception is repeated in action  401 . 
         [0061]    For example, in case the reception of enciphered downlink data comprises reception of enciphered GMM data via a logical link entity having a service access point identifier, SAPI, equal to 1, then the determination that the enciphered downlink data cannot be deciphered comprises a determination of a first predetermined number (i.e. a first N value) of CRC failures associated with the received enciphered GMM data. 
         [0062]    In another example, in case the reception of enciphered downlink data comprises reception of enciphered user data via a logical link entity having a service access point identifier, SAPI, equal to any of 3, 5, 7, 9 and 11, then the determination that the enciphered downlink data cannot be deciphered comprises a determination of a second predetermined number (i.e. a second N value) of CRC failures associated with the received enciphered user data. 
         [0063]    The second predetermined number of CRC failures, that is associated with the user data, is in some embodiments larger than the first number of predetermined number of CRC failures, which is associated with the GMM data. That is, since user data is typically less critical than GMM data, it is acceptable to wait several retransmissions of the downlink data  550  before resolving the problem by operating an authentication procedure. In fact, it is advisable to handle GMM data failures early since no user data communication can take place until all GMM data has been received successfully. 
         [0064]    Action  409   
         [0065]    If no failure is determined in action  405  in the CRC in action  403 , the downlink data  550  is deciphered and provided to a higher layer in the communication protocol stack  201 . 
         [0066]    Action  411   
         [0067]    When it has been determined that the downlink data  550  could not be deciphered, for example as determined by a number of CRC failures, then the LLC entity  522  in the wireless communication device  506  provides a ciphering failure indicator  552  to the GMM entity  521  in the wireless communication device  506 . The ciphering failure indicator  552  may be in the form of a status message with a cause “Ciphering Failure”. This will be internal to the wireless communication device and the network node will not be aware of this cause. But this cause will trigger a CKSN renegotiation procedure as follows. 
         [0068]    Action  413   
         [0069]    As a consequence of receiving the ciphering failure indicator  552 , the GMM entity  521  in the wireless communication device  506  transmits a message  554  to the GMM entity  532  in the network node  530 . For example, the message  554  may be a routing area update request message and the message may also be an attach request message. In any case, the message  554  comprises a CKSN information element that has a value of 7. 
         [0070]    A CKSN information element with value 7 has a defined meaning of “No key is available” in the context of transmission of such request messages from the wireless communication device  506  to the network node  530 . After receiving a message having a CKSN=7, the GMM entity  532  in the network node  530  will understand that the wireless communication device does not have valid authentication parameter and hence will trigger an authentication procedure as follows. 
         [0071]    The GMM entity  532  in the network node  530  will transmit a GMM authentication and ciphering request message  556  to the GMM entity  521  in the wireless communication device  506 . The authentication and ciphering request message  556  comprises a CKSN information element that has a value that may be used by the wireless communication device  506  in subsequent enciphered communication between the wireless communication device  506  and the network node  530 . More specifically, the received CKSN identifies a security context that comprises a security key that may be used for the subsequent enciphered communication. 
         [0072]    Action  415   
         [0073]    The GMM entity  521  in the wireless communication device  506  receives the GMM authentication and ciphering request message  556  from the GMM entity  532  in the network node  530 . 
         [0074]    Action  417   
         [0075]    The GMM entity  521  in the wireless communication device  506  processes the authentication and ciphering request message  556 . In this processing, the security key in the security context identified by the CKSN value of the authentication and ciphering request message  556  is obtained. 
         [0076]    Action  419   
         [0077]    The security key obtained from the security context identified by the CKSN value is provided via a message  558  from the GMM entity  521  in the wireless communication device  506  to the LLC entity  522  in the wireless communication device  506 . 
         [0078]    Action  421   
         [0079]    The GMM entity  521  in the wireless communication device  506  transmits an authentication and ciphering response message  560  to the GMM entity  532  in the network node  530 , which is processed according to standard procedures in the network node  530 , whereupon the GMM entity  532  in the network node  530  transmits an accept message  562  to the GMM entity  521  in the wireless communication device  506 . This accept message  562  is an accept message for the request message  554  transmitted by the GMM entity  521  in the wireless communication device  506  in action  413 . 
         [0080]    Action  423   
         [0081]    The accept message  562  is received in the GMM entity  521  in the wireless communication device  506 , thus concluding the routing area or attach procedure that was initiated by the transmission of the request message  554  in action  413 . Although the authentication procedure is independent of the routing area or attach procedures, the authentication procedure is also concluded by the reception of the accept message  562 . 
         [0082]    Action  425   
         [0083]    Having received it in action  415 , the LLC entity  522  in the wireless communication device  506  is in possession of the security key received in message  558  and uses this security key in encrypted communication with the LLC entity  531  in the network node  530  as illustrated by signals  564 . 
         [0084]    Turning now to  FIG. 6 , embodiments of a wireless communication device  600  will be described in some more detail. The wireless communication device  600 , which may be one of the wireless communication devices  106 ,  506  discussed above in connection with  FIGS. 1-5 , is for communication with a GPRS wireless network, such as the wireless network  100 . The wireless communication device  600  comprises radio frequency circuitry  606 , a processor  602  and a memory  604 . The memory  604  contains instructions executable by the processor  602  whereby the wireless communication device  600  is operative to:
       receive, in a logical link control, LLC, entity in the wireless communication device, enciphered downlink data from a LLC entity in the wireless network,   determine, in the LLC entity in the wireless communication device, that the enciphered downlink data cannot be deciphered,   provide, from the LLC entity in the wireless communication device as a consequence of the determination that the enciphered downlink data cannot be deciphered, a ciphering failure indicator to a GPRS mobility management, GMM, entity in the wireless communication device,   receive, in the GMM entity in the wireless communication device, the ciphering failure indicator and, as a consequence of the reception of the ciphering failure indicator in the GMM entity in the wireless communication device, providing an authentication procedure trigger from the GMM entity in the wireless communication device to a GMM entity in the wireless network, and   operate an authentication procedure wherein the GMM entity in the wireless communication device communicates with the GMM entity in the wireless network via the respective LLC entities in the wireless communication device and the wireless network, whereby the LLC entity in the wireless communication device obtains information for enabling enciphering and deciphering in subsequent communication between the LLC entity in the wireless communication device and the LLC entity in the wireless network.       
 
         [0090]    The instructions that are executable by the processor  602  may be software in the form of a computer program  641 . The computer program  641  may be contained in or by a carrier  642 , which may provide the computer program  641  to the memory  604  and processor  602 . The carrier  642  may be in any suitable form including an electronic signal, an optical signal, a radio signal or a computer readable storage medium. 
         [0091]    In some embodiments, the provision of an authentication procedure trigger from the GMM entity in the wireless communication device to the GMM entity in the wireless network comprises transmitting any of a routing area update request message and an attach request message that comprises a ciphering key sequence number, CKSN, information element having a value of 7. 
         [0092]    In some embodiments, the GMM entity in the wireless communication device receives a CKSN in a GMM authentication and ciphering request message, the received CKSN identifying a security context that comprises a security key. 
         [0093]    In some embodiments, the memory  604  contains instructions executable by the processor  602  whereby the wireless communication device  600  is further operative to:
       obtain, in the GMM entity in the wireless communication device, the security key from the security context identified by the received CKSN, and the obtaining of the information for enabling enciphering and deciphering in subsequent communication between the LLC entity in the wireless communication device and the LLC entity in the wireless network comprises:   receiving, in the LLC entity in the wireless communication device, the security key from the GMM entity in the wireless communication device.       
 
         [0096]    In some embodiments, the reception of enciphered downlink data comprises reception of enciphered GMM data via a logical link entity having a service access point identifier, SAPI, equal to 1, and
       the determination that the enciphered downlink data cannot be deciphered comprises a determination of a first predetermined number of cyclic redundancy check, CRC, failures associated with the received enciphered GMM data.       
 
         [0098]    In some embodiments, the reception of enciphered downlink data comprises reception of enciphered user data via a logical link entity having a service access point identifier, SAPI, equal to any of 3, 5, 7, 9 and 11, and
       the determination that the enciphered downlink data cannot be deciphered comprises a determination of a second predetermined number of CRC failures associated with the received enciphered user data.       
 
         [0100]    In some embodiments, the second predetermined number of CRC failures associated with the received enciphered user data is greater than the first predetermined number of CRC failures associated with the received enciphered GMM data. 
         [0101]    Turning now to  FIG. 7 , embodiments of a wireless communication device  700  will be described in some more detail. The wireless communication device  700 , which may be one of the wireless communication devices  106 ,  506  discussed above in connection with  FIGS. 1-5 , is for communication with a wireless network, such as the wireless network  100 . The wireless communication device  700  comprises:
       a receiving module ( 702 ) configured to receive, in a logical link control, LLC, entity in the wireless communication device, enciphered downlink data from a LLC entity in the wireless network,   a determination module ( 704 ) configured to determine, in the LLC entity in the wireless communication device, that the enciphered downlink data cannot be deciphered,   a providing module ( 706 ) configured to provide, from the LLC entity in the wireless communication device as a consequence of the determination that the enciphered downlink data cannot be deciphered, a ciphering failure indicator to a GPRS mobility management, GMM, entity in the wireless communication device,   a receiving module ( 708 ) configured to receive, in the GMM entity in the wireless communication device, the ciphering failure indicator and, as a consequence of the reception of the ciphering failure indicator in the GMM entity in the wireless communication device, providing an authentication procedure trigger from the GMM entity in the wireless communication device to a GMM entity in the wireless network, and   an operating module ( 710 ) configured to operate an authentication procedure wherein the GMM entity in the wireless communication device communicates with the GMM entity in the wireless network via the respective LLC entities in the wireless communication device and the wireless network, whereby the LLC entity in the wireless communication device obtains information for enabling enciphering and deciphering in subsequent communication between the LLC entity in the wireless communication device and the LLC entity in the wireless network.       
 
         [0107]    The wireless communication device  700  may comprise further modules that are configured to perform in a similar manner as, e.g., the wireless communication device  600  described above in connection with  FIG. 6 . 
         [0108]    As used herein, the term “processing module” may refer to a processing circuit, a processing unit, a processor, an Application Specific integrated Circuit (ASIC), a Field-Programmable Gate Array (FPGA) or the like. As an example, a processor, an ASIC, an FPGA or the like may comprise one or more processor kernels. In some examples, the processing module may be embodied by a software module or hardware module. Any such module may be a determining means, estimating means, capturing means, associating means, comparing means, identification means, selecting means, receiving means, transmitting means or the like as disclosed herein. As an example, the expression “means” may be a module, such as a determining module, selecting module, etc. 
         [0109]    As used herein, the expression “configured to” may mean that a processing circuit is configured to, or adapted to, by means of software configuration and/or hardware configuration, perform one or more of the actions described herein. 
         [0110]    As used herein, the term “memory” may refer to a hard disk, a magnetic storage medium, a portable computer diskette or disc, flash memory, random access memory (RAM) or the like. Furthermore, the term “memory” may refer to an internal register memory of a processor or the like. 
         [0111]    As used herein, the term “computer readable medium” may be a Universal Serial Bus (USB) memory, a DVD-disc, a Blu-ray disc, a software module that is received as a stream of data, a Flash memory, a hard drive, a memory card, such as a MemoryStick, a Multimedia Card (MMC), etc. 
         [0112]    As used herein, the term “computer readable code units” may be text of a computer program, parts of or an entire binary file representing a computer program in a compiled format or anything there between. 
         [0113]    As used herein, the terms “number”, “value” may be any kind of digit, such as binary, real, imaginary or rational number or the like. Moreover, “number”, “value” may be one or more characters, such as a letter or a string of letters. “number”, “value” may also be represented by a bit string. 
         [0114]    As used herein, the expression “in some embodiments” has been used to indicate that the features of the embodiment described may be combined with any other embodiment disclosed herein. 
         [0115]    Even though embodiments of the various aspects have been described, many different alterations, modifications and the like thereof will become apparent for those skilled in the art. The described embodiments are therefore not intended to limit the scope of the present disclosure.