In a number of places in the present document, it is mentioned that some value must take a "random" value, in a given range, or more generally with some statistical distribution. Such cases interest only the Mobile Station. It is required that there is a low probability that two MSs in the same conditions (including the case of two MSs of the same type from the same manufacturer) will choose the same value. Moreover, it is required that, if it happens that two MSs in similar conditions choose the same value, the probability of their choices being identical at the next occasion is the same as if their first choices had been different. The meaning of such a specification is that any statistical test for these values, done on a series of similar events, will obtain a result statistically compatible with the specified distribution. This shall hold even in the cases where the tests are conducted with a subset of possible events, with some common parameters. Moreover, basic tests of independence of the values within the series shall pass. Data against which correlation with the values shall not be found are the protocol state, or the IMSI, or identities or other unrelated information broadcast by the network, or the current TDMA frame number.

For the purposes of the present document, the following terms and definitions apply:

• A GSM security context is established and stored in the MS and the network as a result of a successful execution of a GSM authentication challenge. The GSM security context for the CS domain consists of the GSM ciphering key and the ciphering key sequence number. The GSM security context for the PS domain consists of the GPRS GSM ciphering key and the GPRS ciphering key sequence number.
• A UMTS security context is established and stored in the MS and the network as a result of a successful execution of a UMTS authentication challenge. The UMTS security context for the CS domain consists of the UMTS ciphering key, the UMTS integrity key, the GSM ciphering key, the ciphering key sequence number and the GSM Kc128 (if an A5 ciphering algorithm that requires a 128-bit ciphering key is in use). The UMTS security context for the PS domain consists of the GPRS UMTS ciphering key, the GPRS UMTS integrity key, the GPRS GSM ciphering key, the GPRS ciphering key sequence number, the GPRS GSM Kc128 (if a GEA ciphering algorithm that requires a 128-bit ciphering key is in use) and the GPRS GSM Kint (if a GIA integrity algorithm that requires a 128-bit integrity key is in use).
• An MS is attached for emergency bearer services if it has successfully completed an attach for emergency bearer services or if it has only a PDN connection for emergency bearer services established.
• idle mode: In this mode, the mobile station is not allocated any dedicated channel; it listens to the CCCH and the BCCH;
• group receive mode: (Only applicable for mobile stations supporting VGCS listening or VBS listening) In this mode, the mobile station is not allocated a dedicated channel with the network; it listens to the downlink of a voice broadcast channel or voice group call channel allocated to the cell. Occasionally, the mobile station has to listen to the BCCH of the serving cell as defined in TS 43.022 and TS 45.008;
• dedicated mode: In this mode, the mobile station is allocated at least two dedicated channels, only one of them being a SACCH;
• EAB: Extended Access Barring, see TS 22.011.
• group transmit mode: (Only applicable for mobile stations supporting VGCS talking) In this mode, one mobile station of a voice group call is allocated two dedicated channels, one of them being a SACCH. These channels can be allocated to one mobile station at a time but to different mobile stations during the voice group call;
• packet idle mode: (only applicable for mobile stations supporting GPRS) In this mode, mobile station is not allocated any radio resource on a packet data physical channel; it listens to the BCCH and the CCCH, see TS 44.060.
• packet transfer mode: (only applicable for mobile stations supporting GPRS) In this mode, the mobile station is allocated radio resource on one or more packet data physical channels for the transfer of LLC PDUs.
• main DCCH: In dedicated mode and group transmit mode, only two channels are used as DCCH, one being a SACCH, the other being a SDCCH or a FACCH; the SDCCH or FACCH is called here "the main DCCH";
• A channel is activated if it can be used for transmission, in particular for signalling, at least with UI frames. On the SACCH, whenever activated, it must be ensured that a contiguous stream of layer 2 frames is sent;
• A TCH is connected if circuit mode user data can be transferred. A TCH cannot be connected if it is not activated. A TCH which is activated but not connected is used only for signalling, i.e. as a DCCH;
• The data link of SAPI 0 on the main DCCH is called the main signalling link. Any message specified to be sent on the main signalling link is sent in acknowledged mode except when otherwise specified;
• The term "to establish" a link is a short form for "to establish the multiframe mode" on that data link. It is possible to send UI frames on a data link even if it is not established as soon as the corresponding channel is activated. Except when otherwise indicated, a data link layer establishment is done without an information field.
• "channel set" is used to identify TCHs that carry related user information flows, e.g., in a multislot configuration used to support circuit switched connection(s), which therefore need to be handled together.
• A temporary block flow (TBF) is a physical connection used by the two RR peer entities to support the uni-directional transfer of LLC PDUs on packet data physical channels, see TS 44.060.
• RLC/MAC block: A RLC/MAC block is the protocol data unit exchanged between RLC/MAC entities, see TS 44.060.
• A GMM context is established when a GPRS attach procedure is successfully completed.
• Network operation mode
  The network operation modes I and II are defined in TS 23.060.
  The network operation mode shall be indicated as system information. For proper operation, the network operation mode should be the same in each cell of one routing area.
• GAN mode: See TS 43.318.
• GPRS MS operation mode
  The three different GPRS MS operation modes A, B, and C are defined in TS 23.060.
• RR connection: A RR connection is a dedicated physical circuit switched domain connection used by the two RR or RRC peer entities to support the upper layers' exchange of information flows.
• PS signalling connection is a peer to peer Iu mode connection between MS and CN packet domain node.
• Inter-system change is a change of an MS from A/Gb mode to Iu mode of operation or vice versa, or from S1 mode to A/Gb mode or Iu mode of operation.
• GPRS: Packet services for systems which operate the Gb or Iu-PS interfaces.
• GSM ciphering key: A 64-bit CS GSM ciphering key
• GSM Kc₁₂₈: A 128-bit CS GSM ciphering key
• GPRS GSM ciphering key: A 64-bit PS GSM ciphering key
• GPRS GSM Kc₁₂₈: A 128-bit PS GSM ciphering key
• GPRS GSM Kint: A 128-bit PS GSM integrity key.
• The label (A/Gb mode only) indicates this section or paragraph applies only to a system which operates in A/Gb mode, i.e. with a functional division that is in accordance with the use of an A or a Gb interface between the radio access network and the core network. For multi system case this is determined by the current serving radio access network.
• The label (Iu mode only) indicates this section or paragraph applies only to a system which operates in UTRAN Iu mode, i.e. with a functional division that is in accordance with the use of an Iu-CS or Iu-PS interface between the radio access network and the core network. For multi system case this is determined by the current serving radio access network.
• In A/Gb mode,... Indicates this paragraph applies only to a system which operates in A/Gb mode. For multi system case this is determined by the current serving radio access network.
• In Iu mode,... Indicates this paragraph applies only to a system which operates in UTRAN Iu mode. For multi system case this is determined by the current serving radio access network.
• In A/Gb mode and GERAN Iu mode,... Indicates this paragraph applies only to a system which operates in A/Gb mode or GERAN Iu mode. For multi system case this is determined by the current serving radio access network.
• In UTRAN Iu mode,... Indicates this paragraph applies only to a system which operates in UTRAN Iu mode. For multi system case this is determined by the current serving radio access network.
• In a shared network,... Indicates this paragraph applies only to a shared network. For the definition of shared network see TS 23.122.
• Multi-Operator Core Network (MOCN) with common GERAN: a network in which different core network operators are connected to a shared GERAN broadcasting only a single, common PLMN identity.
• Chosen PLMN: The same as selected PLMN as specified in TS 23.122.
• A default PDP context is a PDP context activated by the PDP context activation procedure that establishes a PDN connection. The default PDP context remains active during the lifetime of the PDN connection.
• A PDP context for emergency bearer services is a default PDP context which was activated with request type "emergency", or any secondary PDP contexts associated to this default PDP context.
• Non-emergency PDP context: Any PDP context which is not a PDP context for emergency bearer services.
• SIM, Subscriber Identity Module (see TS 42.017).
• USIM, Universal Subscriber Identity Module (see TS 21.111).
• MS, Mobile Station. The present document makes no distinction between MS and UE.
• MS configured for dual priority: An MS which provides dual priority support is configured for NAS signalling low priority and also configured to override the NAS signalling low priority indicator (see TS 24.368, TS 31.102).
• Cell Notification is an (optimised) variant of the Cell Update Procedure which uses the LLC NULL frame for cell change notification which does not trigger the restart of the READY timer
• DTM: Dual Transfer Mode, see TS 44.018 and TS 43.055
• The term "eCall only" applies to a mobile station which is in the eCall only mode, as described in TS 22.101.
• "removal of eCall only restriction" means that all the limitations as described in TS 22.101 for the eCall only mode do not apply any more.
• "SMS-only service": A subset of services which includes only short message service. The MS can request "SMS-only service" in order to obtain SMS.
• Access domain selection: The process to select whether the CS domain or the IMS/IP-CAN is used to transmit the call control signalling between MS and core network. Definition derived from TS 23.221.
• APN based congestion control: Congestion control in session management where the network can reject session management requests from MSs or deactivate PDP contexts when the associated APN is congested.
• NAS level mobility management congestion control: Congestion control mechanism in the network in mobility management. "NAS level mobility management congestion control" consists of "subscribed APN based congestion control" and "general NAS level mobility management congestion control".
• General NAS level mobility management congestion control: The type of congestion control that is applied at a general overload or congestion situation in the network, e.g. lack of processing resources.
• Group specific session management congestion control: Type of congestion control at session management level that is applied to reject session management requests from MSs belonging to a particular group when one or more group congestion criteria as specified in TS 23.060 are met.
• Subscribed APN based congestion control: Congestion control in mobility management where the network can reject attach requests from MSs with a certain APN in the subscription.
• Mapped P-TMSI: A P-TMSI which is mapped from a GUTI previously allocated to the MS by an MME. Mapping rules are defined in TS 23.003. Definition derived from TS 23.401.
• Native P-TMSI: A P-TMSI previously allocated by an SGSN. Definition derived from TS 23.401.
• Valid LAI: A LAI that is not deleted LAI.
• EMM Combined UE Waiting Flag: See TS 29.018.
• Power Saving Mode: Power saving mode allows the MS to reduce its power consumption. When power saving mode is active in the MS, the MS is registered to the network and in PMM-IDLE mode (in Iu mode), EMM-IDLE mode (in S1 mode) or the READY timer is not running (in A/Gb mode) but the AS layer is deactivated. Definition derived from TS 23.060 and TS 23.401.
• ACDC: Application specific Congestion control for Data Communication, see TS 22.011.
• Highest ranked ACDC category: The ACDC category with the lowest value as defined in TS 24.105.
• Extended idle-mode DRX cycle: Extended idle-mode DRX cycle allows the MS to reduce its power consumption in PMM-IDLE mode (in Iu mode) or when the READY timer is not running (in A/Gb mode) or in EMM-IDLE mode (in S1 mode). Extended idle-mode DRX cycle is associated with the eDRX cycle value. Definition derived from TS 23.060 and TS 23.401.
• EC-GSM-IoT: Extended coverage in GSM for IoT is a feature which enables extended coverage operation. See TS 43.064.

  For the purposes of the present document, the following terms and definitions given in TS 23.401, subclause 3.2, apply:   For the purposes of the present document, the following terms and definitions given in TS 24.301 apply:   For the purposes of the present document, the following terms and definitions given in TS 23.272 apply:   For the purposes of the present document, the following terms and definitions given in TS 33.401 apply:   For the purposes of the present document, the following terms and definitions given in TS 23.251 apply:   For the purposes of the present document, the following terms and definitions given in TS 23.122 apply:   For the purposes of the present document, the following terms and definitions given in TS 23.216 apply:   For the purposes of the present document, the following terms and definitions given in TS 23.251 and TS 44.018 apply:   For the purposes of the present document, the following terms and definitions given in TS 44.018 apply: For the purposes of the present document, the following terms and definitions given in TS 23.003 apply:   For the purposes of the present document, the following terms and definitions given in TS 23.161 apply:   For the purposes of the present document, the following terms and definitions given in TS 24.302 apply:   For the purposes of the present document, the following terms and definitions given in TS 23.060 apply:   For the purposes of the present document, the following terms and definitions given in TS 24.161 apply:   For the purposes of the present document, the following terms and definitions given in TS 23.167 apply:   For the purposes of the present document, the following terms and definitions given in TS 22.101 apply:   For the purposes of the present document, the following terms and definitions given in TS 23.501 apply:   For the purposes of the present document, the following terms and definitions given in TS 24.501 apply:   For the purposes of the present document, the following terms and definitions given in TS 23.221 apply:   For the purposes of the present document, the following terms and definitions given in TS 23.038 apply: