1. GSM Signaling Overview] GSM signaling defines the communications between the mobile andthe network] Signaling has to be carried through the network and across the air-interface to the mobile] Different protocols are used across different interfaces] All GSM signaling is based on the Open Systems Interconnect (OSI)model used for computer systems] The MSC uses ITUs Signaling System No:7, (SS7 or CCS7) for all itssignaling; to the BSC, HLR, VLR and to other networks] The Air-interface and A-bis signaling is based on ISDN Link AccessProtocol (LAP-D and LAP-Dm)] Signaling channels are integrated into the air-interface as the BCCH,PCH, AGCH, SDCCH, SACCH and FACCH] Signaling across all interfaces is specified in the standards to allowdifferent equipment manufacturers for each unit TWS Proprietary - www.tws -inc.com - (770) 752-7033

2. Mobile Signaling] When the mobile is first switched on it is underthe control of its own internal algorithms.] It performs the following sequence:c Search for GSM frequenciesc Find a FCCH and synchronize frequencyc Find a SCH and synchronize timec Listen for a BCCH and download informationabout the systemc Download idle neighbor list and makemeasurementsc Select a best server and camp on itc If the user wants to make a call, the mobile has tosignal to the network.c It does this by sending a service request to thenetwork on the RACH. TWS Proprietary - www.tws -inc.com - (770) 752-7033 3. GSM SIGNALLING Switching SystemVLR AC NSSMAP MAPMAPMAPVLR HLR EIR MAPMAPMSC ISUPGMSCPSTNTUP BSSAPBase StationBSC System (BSS)PLMN LAPD (GSM)ISDNBTSSS7 User Parts: MAP: SS7, Mobile Application PartLAPDmBSSAP: SS7, Base Station Sub-System Application PartMS ISUP: SS7, International Subscriber User Part TUP: SS7, Telephone User Part LAPD: ISDN, Link Access Protocol Version D TWS Proprietary - www.tws -inc.com - (770) 752-7033 4. GSM SignalingOpen Systems Interconnect uses layers where only layer 1, the physicallayer is actually physically connected between devices. Messages are sentbetween devices by handing them down to lower layers from transmissionacross the physical interface.OSI - ModelGSM Equivalent 7APPLICATION USER 6 PRESENTATION TASKS 5SESSION 4 TRANSPORT 3 NETWORK NETWORK Network MessagesGSM 2 DATA LINK DATA LINKFraming / AddressingNETWORKPHYSICAL Coding / ModulationTASKS 1PHYSICALTWS Proprietary - www.tws -inc.com - (770) 752-7033 5. OSI Layers Layer 3Network Layer : Carries signaling messages, for getting the message toLayer 3 Layer 3its destination. Provides connection oriented (dedicated signaling link) or connectionless services (packet-type signaling). Example: Radio Resource message sent from MSC to BSC.Layer 2 Layer 2Layer 2 Data Link Layer : Transfers frames error free between nodes. Concerned with error detection, framing, re-transmission Example: LAPD protocol on A-bis between BSC and BTS.Layer 1 Layer 1Layer 1 Physical Layer: Transmits all information across the physical medium. Specifies the physical medium used: mechanical,Information Flow electrical, functional and procedural characteristics. Example: GMSK modulation on an RF carrier for the Air-interface between the BTS and the MS TWS Proprietary - www.tws -inc.com - (770) 752-7033 6. Signaling Layers for the Air InterfaceLayer 1: Functions required to transfer bit steams over physical TDMA / FDMA channels: j Ciphering j Setting of timing advance & TX power j Channel Coding j Mapping of logical channels onto physical channelsLayer 2: Provides a reliable signaling link between MS and the network. Protocol is based on the LAPDm of ISDN j Framing j Addressing j Error correctionLayer 3: Takes care of the main control of the MS -network procedures. It is split into3 sublayers: j Radio Resource Management j Mobility Management j Connection ManagementTWS Proprietary - www.tws -inc.com - (770) 752-7033 7. SpeechAir-interface LayersSpeechUser Data User DataSignaling OSI layer 3 Network FunctionsSignalingOSI layer 2 Data link functionsBuilds frames, requestsacknowledgementReconstruct frames, acknowledgesChannel coding,error protection,Error correction,interleaving deinterleavingOSI layer 1 Physical layer EqualizationTransmitter ReceiverRFRF Modulation DemodulationTWS Proprietary - www.tws -inc.com - (770) 752-7033 8. Network Layer] The network layer is split into three sub-layersNetwork Layerc RR - radio resource management: Layer 3 c routes messages to the correct channels CMCC SSSMS c establishes and maintains physicalconnections for control and traffic channels.c MM - mobility management:Mobility Management MM c controls authentication and securitymanagement.Radio Resources RR c provides services for the CM layer.c CM - connection management: Data Link Layer c CC: call control: responsible for establishing,maintaining and releasing calls Layer 1: Physical Layer c SS: supplementary services: data etc c SMS: short message services TWS Proprietary - www.tws -inc.com - (770) 752-7033 9. Signaling Protocol Reference Model BSSNSSTo other processesOther applications,within the BSS A - Interfaceie. call control BSSAP BSSAPOperation &maintenance info. to BSSBSSTo air interfaceDTAP DTAP OA&M centerMAP MAPtransmissionequip.BSSBSSDistribution function Distribution functionOMAP OMAPSCCP SCCP To otherusers MTPMTP of the SCCPand MTP PhysicalLayer Terminology: DTAP (direct transfer application part) BSSMAP (BSS management application part) BSS OMAP (operation & maintenance application part)Note: X.25 can be used SCCP (signaling connection control part) for transferring O & M MTP (message transfer part)informationTWS Proprietary - www.tws -inc.com - (770) 752-7033 10. GSM Network Protocol ModelThe MSC and the mobile always control all the network signaling.MS BTSBSC MSCCM Layer 3CMMMNetwork MM BSSAPBSSAP BSSAPRRRRBTSMBTSMSCCP SCCP Layer 2Data Link LAPDm LAPDm LAPDLAPD MTPMTP Layer 1 RadioRadio64 kbit/s 64 kbit/s64 kbit/s 64 kbit/sPhysicalAir - InterfaceA - bisA - InterfaceTWS Proprietary - www.tws -inc.com - (770) 752-7033 11. Example Page JimMobile recognizesLayer 3 message Layer 3 messagePage Jim andPage Jimsends response topage MSC BSC Layer 2Layer 2Layer 2recognizes aLayer 2recognizes aLayer 2frames message for selectsmessage for the selectsLayer 2 messagethe mobile andBTSmobile andcorrect BSCdecodesconverts toconverts tomessageLAPDmLAPDBTSLayer 1 sendsMS Layer 1 BSC Layer 1 Layer 1 sendsLayer 1messagereceives BTS Layer 1 receives 64 kbitmessage acrosssendsacross A-bis:PCHreceives A-bissignaling from64 kbit signalingmessageT1 or message MSC channelon PCH microwaveTWS Proprietary - www.tws -inc.com - (770) 752-7033 12. Radio Resource Messages] Radio resource functions are controlled by the BSC and include: c SACCH measurement reporting on the uplink c System Information messages 5&6 transmitted on the downlink c Immediate assignment (assignment of SDCCH) c Assignment command (from SDCCH to TCH) c Control of the mobile during handover c Intra-BSC handovers c Frequency hopping c Channel mode changes c Ciphering c Channel release procedures c Radio link failure TWS Proprietary - www.tws -inc.com - (770) 752-7033 13. Radio Resource Messages] Assignment request] Handover Request] Assignment complete ] Handover candidate inquiry] Assignment failure] Handover request acknowledge] Handover required] Block ] Handover required reject] Overload] Handover command] Unblock ] Handover complete] Handover failure] Clear command] Clear complete] Paging] Clear request] Reset] Cipher Mode Command ] Queuing] Cipher Mode Complete] Trace Invocation TWS Proprietary - www.tws -inc.com - (770) 752-7033 14. System Information Messages] The System Information] System Information Messages 1 toMessages are sent to the4 are sent on the BCCH and rotatedmobile from the network on thewith PCH, AGCH, SCH and FCCH,BCCH in Idle mode and on theand maybe the SDCCH.SACCH in active mode. ] System Information Messages 5 &] The Physical Information6 are transmitted continuously onMessages are very similar and the SACCH to active mobiles on theare sent on the FACCH after a downlink while the measurementhandover. report is being sent on the uplink.] They contain the basic] The contents of the Systeminformation that the mobile Information Messages are given inneeds to gain access to the the following slides:network. TWS Proprietary - www.tws -inc.com - (770) 752-7033 15. System Information Messages] System Information Type 1: ] System Information Type 2:1) Cell Channel description (CA) 1) Neighbour cells description which which gives the ARFCNs used ingives the ARFCNs of the the cellneighbour cells to be monitored2) RACH control parameters which by the mobile. Note that this is an includes: offset and a bit map listing up toc the maximum number of124 ARFCNs.retransmissions on the RACH2) PLMN permitted which lists: thec the number of slots to spread thenetwork colour codes (NCCs)transmissionswhich the mobile can use.c the cell barred for access 3) the RACH control parameters asparameterSystem Information Type 1.c call re - establishment allowedc emergency call allowedc control class allowed.TWS Proprietary - www.tws -inc.com - (770) 752-7033 16. System Information Messages] System Information Type 3:4) Cell Options including1) Cell Identity (CI) to identify any cellc Power Control enabledin a given location areac DTX enabledc the value of the radio link timeout2) Location Area Identification counterincluding:5) Cell selection parameters c the Mobile Country Code (MCC) including: c the Mobile Network Code (MNC)c the Cell Reselect Hysteresis parameter c the location area code (LAC)c the maximum mobile power on the3) Control channel descriptioncontrol channel MsTxPwrMaxCCH including: c the minimum access threshold c the attach / detach parameter (ATT)RXLEVMin. c the number of blocks reserved for6) the RACH control parameters as access grant (AG)System Information Type 1. c the common control channel configuration, ie whether it is combined with an SDCCH etc. TWS Proprietary - www.tws -inc.com - (770) 752-7033 17. System Information Messages] System Information Type 4:1) Location area identification as inSystem Information Type 3 ] System Information Type 5:2) Cell selection parameters as in System 1) Neighbour cells description whichInformation Type 3 gives the ARFCNs of the3) RACH control parameters as in neighbour cells to be monitoredSystem Information Type 1and reported on by the mobile.4) Cell Broadcast Control ChannelNote that this is also an offset(CBCH) description which gives the and a bit map listing up to 124description of the channel used forARFCNs.cell broadcast5) Cell Broadcast Control Channel mobileallocation to give the mobile theARFCN used for the CBCH TWS Proprietary - www.tws -inc.com - (770) 752-7033 18. System Information Messages] System Information Type 6:1) Cell Identity (CI) to identify any cell in ] Physical Informationa given location area. Message:2) Location Area Identification including 1) Contains the timing advance c the Mobile Country Code (MCC) for the mobile and is sent on c the Mobile Network Code (MNC) the FACCH after a handover c the location area code (LAC). if the handover is to another3) Cell Options includingsite, ie a non - synchronous c Power Control enabled handover. It is not sent for a c DTX enabled intra-site synchronous c the value of the radio link timeout counter handover. (Either between4) PLMN permitted which lists thesectors of the same site or a network colour codes (NCCs) which timeslot shuffle) the mobile can use.. TWS Proprietary - www.tws -inc.com - (770) 752-7033 19. Call Control Messages] Call Establishment Messages ] Call Information Phase Messagesc AlertingcModifyc Call confirmedcModify Completec Call proceeding cModify Rejectc Connect cUser Informationc Connect Acknowledgec Emergency Setup ] Connection Management Messagesc ProgresscCM Service Acceptc Setup cCM Service RejectcCM Service Request] Call Clearing cCM Re-establishment Requestc Disconnectc Release ] Miscellaneous Messagesc Release Completec Start / Stop DTMF Tonesc Notifyc Status TWS Proprietary - www.tws -inc.com - (770) 752-7033 20. Mobility Management Messages] Registration Messagesc IMSI Detachc Location Updating Requestc Location Updating Acceptc Location Updating RejectLAC 1LAC 2] Security Messagesc Authentication Requestc Authentication Responsec Authentication Rejectc Identity Requestc Identity Responsec TMSI Reallocation Commandc TMSI Reallocation Complete TWS Proprietary - www.tws -inc.com - (770) 752-7033 21. GSM Cause Codes Rec 2:10CauseTone 47 Resources unavailable, unspecified6 (see Table 1)49 Quality of Service Unavailable31 Unassigned number650 Requested facility not subscribed 63 No Route to Destination657 Bearer Capability not authorised658 Bearer Capability not available 36 Channel Unacceptable 663 Service or option not available, unspecified616Normal Clearing165 Bearer Service not implemented617User Busy269 Requested Facility not implemented618No User Responding 679 Service or option not implemented, unspecified619User Alerting, No Answer 681 Invalid Call Reference Value621Call Rejected688 Incompatible Destination622Number Changed -91 Invalid Transit Network Selection 627Destination out of order 695 Invalid Message, unspecified628Invalid Number Format696 Mandatory Information Element error 330Response to STATUS ENQUIRY -97 Message Type non-existent or not implemented631Normal, unspecified-98 Message not compatible with calls state or Message Type non-existent or not implemented634No circuit/channel available 399 Information Element non-existent or not implemented 638Network out of order 6100Invalid Information Element contents641Temporary Failure3101Message not compatible with call state642Switching Equipment Congestion 3102Recovery on timer expiry643Access Information Discarded 6111Protocol error, unspecified 644Requested circuit/channel not available3127Interworking, unspecified 6TWS Proprietary - www.tws -inc.com - (770) 752-7033 22. GSM Supervisory TonesToneFrequencyType1Dial Tone (optional) 425 HzContinuous2Subscriber Busy425 HzTone on 500ms*(Called Number)Silence 500ms3Congestion 425 HzTone on 200ms* Silence 500ms4Radio Path Acknowledgement 425 HzSingle Tone (Mobile originated only) 200ms (optional)5{Radio Path Not Available425 Hz200ms} On/off for {Call dropped - Mobile originated only 200ms} 3 bursts6Error/Special Information}950 Hz {Triple Tone*Number Unobtainable } 1400 Hz {Tones on 330ms Authentication Failure }1800 Hz{Silence 1.0s7Call Waiting Tone 425 Hz, on for 400 ms, 8 s silence followed by (425 Hz, on for 150 ms off for 150 ms, on for 150 ms, 8 s silence and repeated as necessary)TWS Proprietary - www.tws -inc.com - (770) 752-7033 23. GSM Signaling Recommendations Air Interface A - bis A - Interface Layer 1 protocol Radio GMSK64 kbit/s E1, T1, CCS7 Physical layer microwave 64 kbit/s MTP GSM Recs Rec 4:04Rec 8:54Rec 8:04 Layer 2 protocol LAPDm LAPD CCS7 / MTP Data link layer GSM Recs Rec 4:06Rec 8:56 Rec 8:06 Layer 3 protocol CM/ MM/ RRCM/ MM/ RR MTP / SCCP Network layerDTAPBSSMAP BSSAP GSM Recs Rec 4:08Rec 8:58 Rec 8:08 TWS Proprietary - www.tws -inc.com - (770) 752-7033 24. GSM Timers] Timers are used to supervise ] Usually, when a timer times out,messages sent across the network.the message is re-transmitted.] The network entity sending the ] If the timer times out again, themessage starts and stops the channels will be released and asupervisory timer. failure will be recorded by the] The mobile uses timers to control itsMSC or BSC.behavior when not under the direct ] Timers are classified as:control of the network, for example, cRadio Resource Timerswhen idle, during a handover or during cMobility Management Timerschannel disconnect.cBSSAP Timers] Various messages are used to trigger cA-bis Timersthe start and stop of each timer.cCall control Timers] The timers allow the MS and BTS time ] There are timers for both Layer 3to respond to requests for functions and Layer 2 functions.resources or to send information.TWS Proprietary - www.tws -inc.com - (770) 752-7033 25. GSM TimersSue Smith TWS GSM Timers - Radio Resource Timers 4th February 97 NameRange DefaultCommentsNetwork T3101 1-5s1sSupervision of network access. Started when IMMEDIATE_ASSIGNMENT is sent to MS. Stops when MS successfully seizes SDCCH. On expiry, newly allocated channels are released and the access request is forgotten. T31073.5 - 10 s 6sSupervision of assignment procedure. Started when ASSIGNMENT_CMD is sent to the mobile. Stopped when ASSIGNMENT_COMplete message is received on the new channel or ASSIGNMENT_FAILURE is received on the old channel. On expiry, all resources are released and the connection with the mobile is released. T31095 - 15 s 8sReleases channels in case of a loss of communication. Started when a lower layer failure is detected by the network when not engaged in a RF procedure. Also used during the channel release procedure. On expiry channels are released. Default is 9 s. T31110.5 sSupervision of channel disconnection. Started when CHANNEL_RELEASE message is sent. On expiry, disconnects the main signalling link. Allows for possible repetition of the disconnection command. T3113 Supervision of paging procedure. Started when PAGING_REQUEST is sent to the mobile and stopped when PAGING_RESPONSE message is received from the MS. This timer must be longer than T3102 plus T3101. If timer times out, network may allow PAGING_REQUEST to be sent again and the T3113 is re-started.MobileT3110 0.5 sUsed to delay channel deactivation after receipt of the CHANNEL_RELEASE message. Allows some time for disconnection of main signalling link. Must be short enough to prevent T3109 timing out. T3120nRACCH+T1 Supervision of network access attempts. Started when CHANNEL_REQUEST message is sent on the RACCH. Stops on receiptof an IMMEDIATE_ASSIGNMENT on the AGCH. On expiry, if the mobile has not exceeded the maximum number ofretransmissions allowed (RET = 4) then the MS sends another CHANNEL_REQUEST and T3120 is loaded with a new value.The value is obtained from T3120 = n RACCH slots + T1 where n = 1..N and N=8 initially and the valaue of "Tx-integer"subsequently, and T1 = 350 ms. T31222 - 255 s6sDelays network access. Started on receipt of an IMMEDIATE_ASSIGNMENT_REJECT message from the network. On expiry, the mobile may attempt to access the network again. TWS Proprietary - www.tws-inc.com - (770) 752-7033 26. GSM TimersHandover T3103 4 - 10 s 6sSupervises the handover in the BSC. Started when the HANDOVER command is sent to the MS. Stopped when theHANDOVER_COMPLETE message is received via the new BTS on the new channel or HANDOVER_FAILURE messagereceived via the old BTS on the old channel. On expiry ALL RF channels are released and the mobile is assumed to be lostduring the handover procedure. T3105100 ms Supervision of repetition frequency of the PHYSICAL INFO message. Started when the network sends the PHYSICAL INFO message to the MS and stopped when any correct frames are received from the MS. On expiry, the PHYSICAL INFO message is sent again up to the number of repetitions (NY1 = 8) and the timer is re-started. If NY1 is reached, the handover is aborted. T3105_F = 100 ms and T3105_D = 280 ms. T3124320 ms Supervision of handover in the MS. Started when the MS receives a HANDOVER_CMD and stops when the HANDOVER_COMPLETE message is sent. If the handover fails due to the BTS failing to receive the HANDOVER_ ACCESS message, or the mobile fails to receive the PHYSICAL INFO message, then the Timer expires and a HANDOVER_FAILURE is recorded. The mobile the deactivates the new channels, reactivates the old channels and continues as if no handover attempt had occurred.TWS Proprietary - www.tws-inc.com - (770) 752-7033 27. GSM TimersSue Smith TWSGSM Timers - Mobility Management Timers4th February 1997 Name Range Default CommentsMobileT321020 s Started when LOC_UPD_REQ sent. Stopped if LOC_UPD_ACK or LOC_UPD_REJ received from network, or on AUTH_REJ. Onexpiry start Timer 3211. T3211 15 s Started on receipt of LOC_UPD_REJ with cause = network failure. Causes a delay before the mobile attempts access to thenetwork again. On expiry restart location update procedure. T3212Time between periodic updates. Started on termination of MM service signalling. Stopped on initiation of MM service signalling.On expiry, initiate location update procedure. T32134sStarted on location update failure. Delays network access attempt. On expiry, generate a new random access attempt. T32205sAllows time to receive network messages on IMSI Detatach. Started on IMSI_DETACH sent to network. Stopped on release fromRadio Management sub-layer. Enter NULL or IDLE into HLR/VLR, not updated. T3230 15 s Cipher mode supervision. Started on CIPHER_REQUEST sent to BTS. Stopped on CIPHERMODE_SETTING. On expiry, provideRELEASE indication to network. T3240 10 s Allows time to disconnect from network. Start on normal end of location update procedure. Stop on receipt of any message fromthe network. On expiry, release RR connection.Network T32505sStart on TMSI_REAL_CMD or LOC_UPD_ACK with new TMSI sent to MS. Stop on TMSI_REAL_COM received. On first expiry,retransmit AUTH_REQ; on second expiry, release RR connections. T32605sSupervision of authentication procedure. Start on AUTHentication_REQuest sent to MS. Stop on AUTH_RESP received. On firstexpiry, retransmit AUTH_REQ; on second expiry, release RR connections. T32705sSupervision of identity procedure. Start on IDENTITY_REQUEST sent to MS. Stop on IDENTITY_RESPONSE received. On firstexpiry, re-transmit IDENTITY_REQUEST; on second expiry, release RR connections. TWS Proprietary - www.tws-inc.com - (770) 752-7033 28. GSM Timers Sue Smith TWS GSM Timers - BSSAP Timers4th February 1997NameRange Default Comments T410 - 120 s60 s Supervision of sending RESET to MSC. Started whenever BSC RESET occurs. Stopped when RESET Acknowledge is receivedfrom MSC. On expiry procedure is repeated until RESET ACK is received. T5 1 - 10 s4sSupervision of OVERLOAD procedure. Started when OVERLOAD message is received from MSC. On expiry new OVERLOADmessages are taken into account. T6 3 - 20 s 10 s Supervision of OVERLOAD procedure. Started with T5 when OVERLOAD message is received from MSC. On expiry traffic isincreased to next level. T7 5 - 30 s 20 s Supervision of periodicity of HANDOVER_REQUIRED message. Started when HANDOVER_REQUIRED message is sent toMSC. Stopped when HANDOVER_COMMAND message is received from MSC. On expiry, handover procedure is repeated. T8 8 - 15 s 12 s Supervision of handover procedure in source BSC. Started when HANDOVER_COMMAND message is received from MSC.Stopped when CLEAR_COMMAND (external handover) is received from MSC. On expiry, ASSIGNMENT_FAILURE message issent to MSC.T10 4 - 14 s8sSupervision of assignment procedure. Started when ASSIGNMENT_COMMAND message is sent to the MS via the BTS.Stopped when ASSIGNMENT_COMPLETE or ASSIGNMENT_FAILURE is received from the MS. On expiry,ASSIGNMENT_FAILURE message is sent to MSC.T12 5 - 30 s 15 s Serves as a guard period for local call clearing procedure. Started when a RESET message is received from the MSC. Stoppedwhen a SSP (sub-system prohibited) message is received from SCCP. On expiry RESET_ACKNOWLEDGEMENT sent to MSC. TWS Proprietary - www.tws-inc.com - (770) 752-7033 29. GSM Timers Sue Smith TWS GSM Timers - ABIS Timers 4th February 97Name RangeDefaultCommentsT910110 s Non-modifiableT9103 2sNon-modifiableT9104 5 - 20 s 15 s Supervision of clear procedure from MSC. Started when CLEAR_REQ is sent to MSC. Stopped when CLEAR_CMD is receivedfrom MSC. On expiry, CHANNEL_REL is sent to mobile, via the BTS.T9105 2 - 240 s10 s Supervision of SCCP connection procedure. Started when SCCP_CONNECTION_REQUEST is sent to the MSC. Stopped whenSCCP_CONNECTION_CONFIRM or _REFUSED is received from MSC. On expiry, CHANNEL_RELEASE is sent to MS via BTS.Set to 31 s.T9108 2sNon-modifiableT9113 8 - 15 s 12 s Supervision of external handover in target BSC. Started when HANDOVER_REQUEST_ACK is sent to MSC. Stopped whenHANDOVER_COMplete is received from MS or when CLEAR_CMD is received from MSC. On expiry CLEAR_REQUEST is sentto MSC.T200240 ms Layer 2 repeat timer. Values depend on timers used to supervise message flow between the MS and the network. For proper operation T200 should be greater than the maximum time between re-transmission of command frames and the reception of their corresponding response or acknowledgement frames but should be shorter than the corresponding Layer 3 timer supervising this message flow.TWS Proprietary - www.tws-inc.com - (770) 752-7033 30. GSM Timers Sue Smith TWS GSM Timers - MSC Timers 4th February 97 Name Range DefaultComments TNT160 - 300 s 300 s Timer deployed to ensure release of SCCP resources. Internal SCCP Integrity Timer TNT2 1 - 30 s5sASSIGNMENT_REQUEST message sent, awaiting for ASSIGNMENT_COMPLETE reply from BSS. On expiry channels arereleased. Value of TNT2 should be greater than BSS timer T10. TNT3 1 - 30 s5sCLEAR_COMMAND message sent, awaiting CLEAR_COMPLETE reply from BSS. On expiry resources are released and mobileis assumed lost during call clear. Value of TNT3 + T102 should be greater than T8 at the BSS. TNT4 1 - 30 s5sCIPHER_MODE_COMMAND message sent, awaiting CIPHER_MODE_COMPLETE reply from BSS. On expiry the connection isreleased and a cipher failure is logged (GMSC601 log). T101 1 - 10 s5sAt MSC-A, HANDOVER_REQUEST message sent, awaiting HANDOVER_REQUEST_ACKNOWLEDGEMENT from BSS. If T101expires, the MSC tries to use another cell from the list of preferred cells. (see NPC parameter) T201 1 - 30 s5sAt MSC-B, HANDOVER_REQUEST message sent, awaiting HANDOVER_REQUEST_ACKNOWLEDGEMENT message at MSC-B after inter-MSC handover. If T201 expires the MSC attempts to use another cell from the preferred cell list if available. T102 1 - 30 s5sWith T103, T104, T202, T204, T210 these supervise the sending of messages between two MSCs for an inter-MSC handover.On expiry resources are released (similar to inter-BSC handover supervisory timers) T32501 - 20 s5sTMSI_REALLOCATE_COMMAND or LOCATION_UPDATE_ACCEPT message sent, awaiting TMSI_REALLOCATE commandfrom mobile station. On initial expiry message re-sent, on second expiry release connection. T32601 - 20 s5sAUTHENTIATION_REQUEST message sent, awaiting AUTHENTICATION_RESPONSE message from mobile. On initial expirymessage re-sent, on second expiry release connection. T32701 - 20 s5sIDENTITY_REQUEST message sent, awaiting IDENTITY_RESPONSE message from mobile. On initial expiry message re-sent, on second expiry release connection.T2_DTAP 30 - 120 s 30 s Call initiated to mobile station and no response message is received. Incoming call timer for network side integrity. On expiry,release connection. T30145 - 300 s 180 s ALERT message is received for the mobile, awaiting sending of CALL_CONFIRMED message. On expiry, release connection. TWS Proprietary - www.tws-inc.com - (770) 752-7033 31. GSM TimersT303 1 - 60 s 30 s SETUP message is received for the mobile station, awaiting sending of CALL_CONFIRMED message. On expiry, release connection.T305 1 - 60 s 30 s DISCONNECT message sent to mobile, awaiting RELEASE_COMPLETE from the mobile. On expiry RELEASE message sent.T308 1 - 60 s 30 s RELEASE message sent to the mobile. Awaiting ALERT, CONNECT or DISCONNECT message from the network. On expiry, DISCONNECT sent.T310 1 - 60 s 30 s CALL_CONFIRMED message is sent to the mobile, awaiting ALERT, CONNECT or DISCONNECT message from the network. On expiry, DISCONNECT sent.T313 1 - 60 s 30 s CONNECT message has been sent to the mobile, awaiting reply of CONNECT_ACKNOWLEDGEMENT. On expiry, DISCONNECT sent.TC1N 1 - 60 s 20 s CP_DATA_INDICATION sent to the mobile, awaiting reply of CP_ACKNOWLEDGEMENT. Error indication on second expiry. TWS Proprietary - www.tws-inc.com - (770) 752-7033 32. CALL SET-UP - Mobile TerminateMSBTSBSCMSCRR MM BSS MAP CMPAGING REQUEST(PCH) PAGING COMMAND CMPAGING COMMAND CMCHANNEL REQUEST (RACH) T3113CHANNEL REQUIRED T3120(RR)CHANNEL ACTIVATION(IMMEDIATE ASSIGNMENT) RR nRACCH>T3101 + T3120 + T1 (350ms)CHANNEL ACTIVATION ACKIMM ASSIGN RESIMMEDIATE ASSIGNMENT(AGCH)IMMEDIATE ASSIGN COMMAND RRT3122 (6s)SABM (PAGING RESPONSE)(SDCCH) PAGE RESPONSE CM T3101UA(PAGING RESPONSE) (SDCCH)(RR) 1sESTABLISH INDICATION RRTWS Proprietary - www.tws -inc.com - (770) 752-7033 AUTHENTICATEAUTHENTICATE REQUEST (RAND) AUTHENTICATE REQPONSEAUTHENTICATE RESPONSE (SRES) CIPHER MODE CMD CIPHER MODE COMMANDTNT4 CIPHER MODE COMPLETECIPHER MODE COMPLETE SETUPPHYSICAL CONTEXT REQUESTSETUP T303CALL PROCEEDING PHYSICAL CONTEXT CONFIRM CALL PROCEEDING LAYER 2 TIMERS CHANNEL ACTIVATION(TCH ASSIGN) T200 240ms x 4 rep.T310 THEN T3109 (8s)CHANNEL ACT. ACK RELEASES LOWER LAYER.ASSIGNMENT COMMAND(SDCCH) DATA REQUEST(CM) ASSIGNMENT REQUEST COMMANDCM(FACCH on TCH) SABM (FACCH)call confirmed TNT TNT2 should be T10 T31072greater than T10 6s8s UAcall proc. (5s)ESTABLISH INDICATIONDATA INDICATIONCMASSIGNMENT COMPLETE(CM) ASSIGNMENT COMPLETERF CHANNEL RELEASE (SDCCH) RRRF CHANNEL RELEASE ACKRR ALERTING (FACCH)DATA REQUEST ALERTINGT301CONNECTDATA REQUEST CONNECTCONNECT ACK DATA INDICATION CONNECT ACKNOWLEDGET313 MOBILE DISCONNECT DISCONNECT DATA INDICATIONCLEAR REQUEST RELEASEDATA REQUEST CLEAR COMMAND TNT3RELEASE COMPLETE DATA INDICATION CLEAR COMPLETE(5s) CHANNEL RELEASEDATA REQUESTCHANNEL RELEASET31100.5s DEACTIVATE SACCH T3111T308 DISC RELEASE INDICATION0.5s RELEASE COMPLETE UA RF CHANNEL RELEASE on RF channelrelease RF CHANNEL RELEASE ACK or T3111 expiry Air InterfaceA-Interface A-bis 33. INTER - BSC HANDOVERMobile BTS 1 BSC 1MSCBSC 2BTS 2Mobile RR MM CMBSS MAPRR MM CM BSS MAPSYS INFO 5 & 6BTS MEAS. RESULT (SACCH)MEASUREMENT REPORTMS MEAS. RESULT T7 20s HANDOVER REQUIRED HANDOVER REQUEST CHANNEL ACTIVATIONT101ACT. ACK.Def:5s H/O REQ. ACK.(FACCH)Note: HandoverAccess HANDOVER DETECTHANDOVER ACCESS on FACCH HANDOVER COMMANDDATA REQUESTHANDOVER COMMANDusing T9113RACCH burst(FACCH) PHYSICAL INFO structure RELEASE REQUEST T812sTWS Proprietary - www.tws -inc.com - (770) 752-7033T3113 T3105 12s100ms PHYSICAL INFO6sT102No Phys Info ESTABLISH INDICATION on Synchronised SABM HandoversT8 +T102 + Def: 5sTNT3T3124 UA320msHANDOVER H/O COMPLETE DATA INDICATION COMPLETECLEAR COMMAND TNT3 CLEAR COMPLETERF CHAN. RELEASE RELEASE RF CHAN. REL. ACK Air Interface RELEASE COMPLETEH/OFAILST3124 TIMES OUT HANDOVER ACCESS (FACCH) SABMUA DATA INDICATION HANDOVER FAILURE OLD BSCH/O FAILUREReturn to OldCLEAR COMMANDchannelTNT3 NEW BSC (5s)CLEAR COMPLETE RELEASE RELEASE RF CHANNEL RELEASE COMPLETE RF CH. REL. ACK. Air InterfaceA-bis A-InterfaceA-Interface A-bis 34. LOCATION UPDATE Mobile BTSBSCMSCRR/ CM / MM BSSMAP CHANNEL REQUEST (RACH)CHANNEL REQUIRED CHANNEL ACTIVATION CHANNEL ACTIVATIONACKIMMEDIATE ASSIGNMENT (AGCH) IMMEDIATE ASSIGNMENT CM SERVICE REQUEST (LOC UPDATE) LOCATION UPDATE REQUEST CM (SDCCH)VLR( SDCCH)UPDATE LOCATION AREATWS Proprietary - www.tws -inc.com - (770) 752-7033IDENTITY REQUESTIDENTITY REQUEST T T3270 3 T32305sT3270 2IDENTITY RESPONSE IDENTITY RESPONSE15s 3VLRTMSI 0ACKNOWLEDGE 1 5 s AUTHENTICATION REQUESTAUTH. REQUEST (RAND) T T3260T3260 3 SRES 5s 2AUTHENTICATION RESPONSE AUTH. RESPONSE (SRES) VLR 1 0TMSI, LOC AREAACCEPTED 2 0 CIPHER MODE COMMANDCIPHER MODE CMD (Key) s TNT 4CIPHER MODE COMPLETECIPHER MODE COMPLETE (5S) T321020s LOC UPDATE ACCEPTED T LOC UPDATE ACCEPTED(TMSI) 3T32502 5 T3250 TMSI REALLOCATION COMPLETE 5STMSI REALLOCATION COMPLETE 0 5TMSIRELEASE CHANNEL RELEASES CLEAR COMMAND T3240T3240 ACKNOWLEDGE10s 10s TNT 3RELEASE COMPLETECLEAR COMPLETERELEASE COMPLETE (5S)CHANNEL RELEASE RELEASEDDEACTIVATE SDCCHT3111 DISCUARELEASE INDICATION RELEASE COMPLETE RELEASE RF CHANNELRF CHANNEL RELEASE ACK.S.Smith Dec 94 Air InterfaceA-bis A-Interface