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.

The following terms are used in this Technical Specification:

• 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 3GPP TS 23.022 [14] and TS 45.008. When talker priority is supported, and the network requires priority talker requests to be signalled on the RACH, the mobile station may temporarily leave the group receive mode, and establish a SDCCH, in order to initiate a priority uplink request. Once the priority uplink request has been sent, the SDCCH is released and the mobile returns to group receive mode.
• dedicated mode: In this mode, the mobile station is allocated at least two dedicated channels, only one of them being a SACCH.
• 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. Additionally, when talker priority is supported by the network, further mobile stations may establish RR connections on the group channel in order to initiate an uplink access.
• packet idle mode: (only applicable for mobile stations supporting GPRS services - see TS 23.060) In this mode, mobile station is not allocated any radio resource on a packet data physical channel; it listens to the PBCCH and PCCCH or, if those are not provided by the network, to the BCCH and the CCCH (see TS 44.060) or, if the mobile station has enabled EC operation, to the EC-BCCH and the EC-CCCH, see sub-clause 3.10 and sub-clause 3.5.1a.
• packet transfer mode: (only applicable for mobile stations supporting GPRS services - see TS 23.060) In this mode, the mobile station is allocated radio resource on one or more packet data physical channels for the transfer of LLC PDUs.
• dual transfer mode: (only applicable for mobile stations supporting GPRS and DTM) In this mode, the mobile station is allocated radio resources providing an RR connection and one or more Temporary Block Flow (TS 44.060) on one or more physical channels. The allocation of radio resource for the RR connection and the Temporary Block Flows is co-ordinated by the network to comply with the capabilities of the mobile station in dual transfer mode.
• 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 three different network operation modes I, II, and III 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.
• GPRS MS operation mode: The three different GPRS MS operation modes A, B, and C are defined in TS 23.060.
• DTM handover is a feature used by the network to command a mobile station to move from its old (source) cell to a new (target) cell while operating in dual transfer mode and continue the operation of its ongoing circuit switched service and one or more of its ongoing packet switched services in the new cell. The mobile station is allocated one circuit switched radio resource and packet switched radio resources applicable to the new cell within a DTM HANDOVER COMMAND message.
• Downlink Dual Carrier is a capability of the mobile station to receive on two radio frequency channels simultaneously. It is only applicable for mobiles which support EGPRS.
• Downlink Multi Carrier is a feature allowing resources for a downlink TBF (and optionally an uplink TBF) to be assigned to a mobile station on two or more radio frequency channels in the same or different frequency bands using EGPRS or EGPRS2-A.
• CSG Cells Reporting: Refers to the ability of the mobile station to report measurements, CSG-ID and routing parameters of CSG cells in dedicated mode and dual transfer mode. For UTRAN cells, routing parameters include Cell Identity and optionally the PLMN-ID.
• Extended Access Barring (EAB) is an optional feature used by the network to control whether or not mobile stations configured for EAB are allowed to attempt system access (see TS 22.011). When EAB is in use within a given cell a mobile station configured for EAB reads system information to acquire EAB related information which it uses in conjunction with its Access Class (i.e. a single value in the range 0,1, …9) to determine if it can attempt a system access.
• Selective Ciphering of Downlink SACCH, when ciphering is started between the network and the mobile station, refers to:
• the mechanism used by the network in downlink to cipher or not to cipher any given individual SACCH block selectively according to its content; and accordingly the ability of the mobile station to decode any given individual SACCH block whether it is ciphered or not. See sub-clause 3.4.7a.
• Network sharing: network sharing is an optional feature that allows different core network operators to connect to the same shared radio access network (see TS 23.251). When network sharing is in use within a given cell, the network broadcasts within system information the PLMN identities of the PLMNs sharing the cell. A mobile station supporting network sharing uses this information for its PLMN (re)selection processes and indicates the selected PLMN to the BSS.
• Common PLMN: when network sharing is in use within a given cell, the Common PLMN refers to the PLMN of which the PLMN ID is broadcast in the SYSTEM INFORMATION TYPE 3 and SYSTEM INFORMATION TYPE 4 messages (as part of the Location Area Identification) and, when EC-GSM-IoT is supported in the cell (see TS 43.064, in the EC SYSTEM INFORMATION TYPE 2 message. See sub-clause 9.1.35, sub-clause 9.1.36, sub-clause 9.1.43q and TS 23.251, TS 24.008.
• Additional PLMN: when network sharing is in use within a given cell, an Additional PLMN refers to a PLMN of which the PLMN ID is broadcast in the SYSTEM INFORMATION TYPE 22 message (see sub-clause 10.5.2.37n) and, when EC-GSM-IoT is supported in the cell, in the EC SYSTEM INFORMATION TYPE 4 message (see sub-clause 9.1.43s).
• Domain-specific access control: domain-specific access control is an optional feature that allows the network to send, on a PLMN specific basis, different access control information for the CS and PS domains (see TS 22.011). A mobile station supporting domain-specific access control uses this information for its access control check process. Support of domain-specific access control is possible only if network sharing is supported.
• IP Multimedia Subsystem (IMS): The IP Multimedia Subsystem comprises all CN elements for provision of IP multimedia services, see TS 23.228.
• Single Radio Voice Call Continuity (SRVCC): refers to voice call continuity between IMS over PS access and CS access for calls that are anchored in IMS when the MS is capable of transmitting/receiving on only one of those access networks at a given time; a mobile station supporting SRVCC is enhanced for IMS Service Continuity with the additional MS capabilities described in TS 23.216 for SRVCC from E-UTRAN to UTRAN (HSPA) or GERAN or from UTRAN (HSPA) to E-UTRAN or GERAN or from GERAN to E-UTRAN or UTRAN (HSPA). SRVCC from GERAN to E-UTRAN or UTRAN (HSPA) is known also as CS to PS SRVCC.
• Extended EARFCNs: refers to extended EARFCN value range (0 …262143) with EARFCNs coded over 18 bits. Mobile station and network support of extended EARFCNs is mandatory when network sharing is supported; support of extended EARFCNs is optional otherwise.
  When network sharing is in use within a given cell, the network shall provide extended EARFCNs within the SYSTEM INFORMATION TYPE 23 message, if broadcasted in the cell; additionally when extended EARFCNs is in use within a given cell, the network may provide at least one EARFCN value > 65535 within the SYSTEM INFORMATION TYPE 2quater message.
• Power Efficient Operation (PEO): See TS 43.064
• Coverage Class: See TS 43.064
• EC operation: See TS 43.064
• 1TS EC-RACH: Mapping of the EC-RACH logical channel using one timeslot where EC PACKET CHANNEL REQUEST messages are sent by mobile stations,see TS 45.002
• 2TS EC-RACH: Mapping of the EC-RACH logical channel using two timeslots where EC PACKET CHANNEL REQUEST messages are sent by mobile stations, see TS 45.002
• Multilateration Timing Advance (MTA): See TS 43.059
• Multilateration Observed Time Difference (MOTD): See TS 43.059