Emergency Call
Everybody would know what Emergency Call is.. (it is like 911 in north america, 112 in South Korea etc). So I would not explain what Emergency call is. I will focus more on the type of conditions in which the emergency call is allowed and the details of emergency call protocol sequence.
You can make an Emergency call in several different condition as listed below.
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i) The Cell is not Barred for Emergency Call
-
ii) UE is registered to a cell
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iii) UE has a USIM but the USIM is not provisioned by the network in which the UE is in (In this case, UE would not perform the registeration process to the cell)
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iv) UE does not have any USIM in it(In this case, UE would not perform the registeration process to the cell)
Followings are the protocol sequence and message details for typical cases of emergency call in WCDMA.
Case 1 : Normal Registration and Normal USIM
When you have a USIM in the phone, overall Emergency Call processing is very similar to normal call process except a couple of information elements as marked in the following links.
01) < In Idle Mode >
02) < Make an Emergency Call from UE >
03) RACH Preamble
04) AICH
05) RACH Message
06) RRC : RRC Connection Request
07) RRC : RRC Connection Setup
08) RRC : RRC Connection Setup Complete
09) RRC: initialDirectTransfer + MM : CM Service Request
10) RRC : downlinkDirectTransfer + MM:Authentication Request
11) RRC : uplinkDirectTransfer + MM:Authentication Response
12) RRC : Security Mode Command
13) RRC : Security Mode Complete
14) RRC : uplinkDirectTransfer + CC : Emergency Setup
15) RRC : downlinkDirectTransfer + CC : Call Proceeding
16) RRC : Radio Bearer Setup
17) RRC : Radio Bearer Setup Complete
18) RRC : downlinkDirectTransfer + CC : Alerting
19) RRC : uplinkDirectTransfer + CC : Connect
20) RRC : downlinkDirectTransfer + CC : Connect Acknowledge
21) < Voice Traffic >
< 06) RRC : RRC Connection Request >
rrcConnectionRequest
initialUE-Identity: imsi (0)
imsi: 15 items
Item 0
Digit: 0
Item 1
Digit: 0
Item 2
Digit: 1
Item 3
Digit: 0
Item 4
Digit: 1
Item 5
Digit: 0
Item 6
Digit: 1
Item 7
Digit: 2
Item 8
Digit: 3
Item 9
Digit: 4
Item 10
Digit: 5
Item 11
Digit: 6
Item 12
Digit: 7
Item 13
Digit: 8
Item 14
Digit: 9
establishmentCause: emergencyCall (9)
protocolErrorIndicator: noError (0)
measuredResultsOnRACH
currentCell
modeSpecificInfo: fdd (0)
fdd
measurementQuantity: cpich-Ec-N0 (0)
cpich-Ec-N0: 43
v3d0NonCriticalExtensions
rRCConnectionRequest-v3d0ext
v4b0NonCriticalExtensions
rrcConnectionRequest-v4b0ext
accessStratumReleaseIndicator: rel-8 (4)
v590NonCriticalExtensions
rrcConnectionRequest-v590ext
0... .... predefinedConfigStatusInfo: False
v690NonCriticalExtensions
rrcConnectionRequest-v690ext
ueCapabilityIndication: hsdch-edch (1)
domainIndicator: cs-domain (0)
cs-domain
csCallType: speech (0)
v6b0NonCriticalExtensions
rrcConnectionRequest-v6b0ext
v6e0NonCriticalExtensions
rrcConnectionRequest-v6e0ext
v770NonCriticalExtensions
rrcConnectionRequest-v770ext
mac-ehsSupport: true (0)
v7b0NonCriticalExtensions
rrcConnectionRequest-v7b0ext
v860NonCriticalExtensions
rrcConnectionRequest-v860ext
UL CCCH (Hex) : 38 90 01 01 01 23 45 67 89 48 2B A9 68 A9 40 00 00 00 00 00 00
< 09) RRC: initialDirectTransfer + MM : CM Service Request >
initialDirectTransfer
cn-DomainIdentity: cs-domain (0)
intraDomainNasNodeSelector
version: release99 (0)
release99
cn-Type: gsm-Map-IDNNS (0)
gsm-Map-IDNNS
routingbasis: localPTMSI (0)
localPTMSI
routingparameter: 0000
0... .... dummy: False
nas-Message: 052402035758a605f400000000
GSM A-I/F DTAP - CM Service Request
Protocol Discriminator: Mobility Management messages
.... 0101 = Protocol discriminator: Mobility Management messages (0x05)
0000 .... = Skip Indicator: No indication of selected PLMN (0)
00.. .... = Sequence number: 0
..10 0100 = DTAP Mobility Management Message Type: CM Service Request (0x24)
Ciphering Key Sequence Number
0... .... = Spare bit(s): 0
.000 .... = Ciphering Key Sequence Number: 0
CM Service Type
.... 0010 = Service Type: (2) Emergency call establishment
Mobile Station Classmark 2
Length: 3
0... .... = Spare: 0
.10. .... = Revision Level: Used by mobile stations supporting R99
or later versions of the protocol (2)
...1 .... = ES IND: Controlled Early Classmark Sending option is implemented in the MS
.... 0... = A5/1 algorithm supported: encryption algorithm A5/1 available
.... .111 = RF Power Capability: RF Power capability is irrelevant in this information element (7)
0... .... = Spare: 0
.1.. .... = PS capability (pseudo-synchronization capability): PS capability present
..01 .... = SS Screening Indicator: Capability of handling of ellipsis notation
and phase 2 error handling (1)
.... 1... = SM capability (MT SMS pt to pt capability):
Mobile station supports mobile terminated point to point SMS
.... .0.. = VBS notification reception: no VBS capability or no notifications wanted
.... ..0. = VGCS notification reception: no VGCS capability or no notifications wanted
.... ...0 = FC Frequency Capability: The MS does not support the E-GSM or R-GSM band
1... .... = CM3: The MS supports options that are indicated in classmark 3 IE
.0.. .... = Spare: 0
..1. .... = LCS VA capability (LCS value added location request notification capability):
LCS value added location request notification capability supported
...0 .... = UCS2 treatment: the ME has a preference for the default alphabet
.... 0... = SoLSA: The ME does not support SoLSA
.... .1.. = CMSP: CM Service Prompt:
Network initiated MO CM connection request supported for at least one CM protocol
.... ..1. = A5/3 algorithm supported: encryption algorithm A5/3 available
.... ...0 = A5/2 algorithm supported: encryption algorithm A5/2 not available
Mobile Identity - TMSI/P-TMSI (0x0000)
Length: 5
1111 .... = Unused: 0x0f
.... 0... = Odd/even indication: Even number of identity digits
.... .100 = Mobile Identity Type: TMSI/P-TMSI/M-TMSI (4)
TMSI/P-TMSI: 0x00000000
v3a0NonCriticalExtensions
initialDirectTransfer-v3a0ext
start-Value: 000040 [bit length 20, 4 LSB pad bits, 0000 0000 0000 0000 0100 .... decimal value 4]
laterNonCriticalExtensions
v590NonCriticalExtensions
initialDirectTransfer-v590ext
v690NonCriticalExtensions
initialDirectTransfer-v690ext
v770NonCriticalExtensions
initialDirectTransfer-v770ext
v860NonCriticalExtensions
initialDirectTransfer-v860ext
supportOfCSG: true (0)
UL DCCH (Hex) : 15 00 00 00 60 29 20 10 1A BA C5 30 2F A0 00 00 00 06 00 00 8D 12
< 14) RRC : uplinkDirectTransfer + CC : Emergency Setup >
uplinkDirectTransfer
cn-DomainIdentity: cs-domain (0)
nas-Message: 038e040660040200058140080402600000021f002e0104
GSM A-I/F DTAP - Emergency Setup
Protocol Discriminator: Call Control; call related SS messages
.... 0011 = Protocol discriminator: Call Control; call related SS messages (0x03)
0... .... = TI flag: allocated by sender
.000 .... = TIO: 0
10.. .... = Sequence number: 2
..00 1110 = DTAP Call Control Message Type: Emergency Setup (0x0e)
Bearer Capability - (MS supports at least full rate speech version 1 and half rate speech version 1.
MS has a greater preference for full rate speech version 1 than for half rate speech version 1)
Element ID: 0x04
Length: 6
Octet 3
0... .... = Extension: Extended
.11. .... = Radio channel requirement: MS supports at least full rate speech version 1
and half rate speech version 1.
MS has a greater preference for full rate speech version 1
than for half rate speech version 1
...0 .... = Coding standard: GSM standardized coding
.... 0... = Transfer mode: circuit
.... .000 = Information transfer capability: Speech (0x00)
Octets 3a - Speech Versions
0... .... = Extension: Extended
.0.. .... = Coding: octet used for extension of information transfer capability
..00 .... = Spare bit(s): 0
.... 0100 = Speech version indication: GSM full rate speech version 3(FR AMR) (0x04)
0... .... = Extension: Extended
.0.. .... = Coding: octet used for extension of information transfer capability
..00 .... = Spare bit(s): 0
.... 0010 = Speech version indication: GSM full rate speech version 2(GSM EFR) (0x02)
0... .... = Extension: Extended
.0.. .... = Coding: octet used for extension of information transfer capability
..00 .... = Spare bit(s): 0
.... 0000 = Speech version indication: GSM full rate speech version 1(GSM FR) (0x00)
0... .... = Extension: Extended
.0.. .... = Coding: octet used for extension of information transfer capability
..00 .... = Spare bit(s): 0
.... 0101 = Speech version indication: GSM half rate speech version 3(HR AMR) (0x05)
1... .... = Extension: No Extension
.0.. .... = Coding: octet used for extension of information transfer capability
..00 .... = Spare bit(s): 0
.... 0001 = Speech version indication: GSM half rate speech version 1(GSM HR) (0x01)
Supported Codec List
Element ID: 0x40
Length: 8
System Identification (SysID): UMTS (0x04)
Bitmap Length: 2
Codec Bitmap for SysID 1
0... .... = TDMA EFR: False
.1.. .... = UMTS AMR 2: True
..1. .... = UMTS AMR: True
...0 .... = HR AMR: False
.... 0... = FR AMR: False
.... .0.. = GSM EFR: False
.... ..0. = GSM HR: False
.... ...0 = GSM FR: False
00.. .... = Spare bit(s): 0
..0. .... = OHR AMR-WB: False
...0 .... = OFR AMR-WB: False
.... 0... = OHR AMR: False
.... .0.. = UMTS AMR-WB: False
.... ..0. = FR AMR-WB: False
.... ...0 = PDC EFR: False
System Identification (SysID): GSM (0x00)
Bitmap Length: 2
Codec Bitmap for SysID 2
0... .... = TDMA EFR: False
.0.. .... = UMTS AMR 2: False
..0. .... = UMTS AMR: False
...1 .... = HR AMR: True
.... 1... = FR AMR: True
.... .1.. = GSM EFR: True
.... ..1. = GSM HR: True
.... ...1 = GSM FR: True
00.. .... = Spare bit(s): 0
..0. .... = OHR AMR-WB: False
...0 .... = OFR AMR-WB: False
.... 0... = OHR AMR: False
.... .0.. = UMTS AMR-WB: False
.... ..0. = FR AMR-WB: False
.... ...0 = PDC EFR: False
Service Category - Emergency category
Element ID: 0x2e
Length: 1
0... .... = Spare bit(s): 0
.0.. .... = Automatically initiated eCall: False
..0. .... = Manually initiated eCall: False
...0 .... = Mountain Rescue: False
.... 0... = Marine Guard: False
.... .1.. = Fire Brigade: True
.... ..0. = Ambulance: False
.... ...0 = Police: False
UL DCCH (Hex) : 8B ED 0C 6B 8E C0 0B 01 C7 02 03 30 02 01 00 02 C0 A0 04 02 01 30 00 00 01 0F 80 17 00 82 00
Case 2 : No Registration and No USIM
When there is No USIM in the phone. You may see on the UE display a kind of warning saying "No SIM inserted. Only Emgergency Call is allowed". When you make an emergency call from UE, it would go through following procedure.
UE would send RRC Connection Request with the cause of Emergency Call and with IMEI (Not IMSI nor TMSI) and Network would allow the call setup without going through Authentication and Security procedure.
01) < No Registered : Emergency Only Mode >
02) < Make an Emergency Call from UE >
03) RACH Preamble
04) AICH
05) RACH Message
06) RRC : RRC Connection Request
07) RRC : RRC Connection Setup
08) RRC : RRC Connection Setup Complete
09) RRC: initialDirectTransfer + MM : CM Service Request
10) RRC : downlinkDirectTransfer + MM : CM Service Accept
14) RRC : uplinkDirectTransfer + CC : Emergency Setup
15) RRC : downlinkDirectTransfer + CC : Call Proceeding
16) RRC : Radio Bearer Setup
17) RRC : Radio Bearer Setup Complete
18) RRC : downlinkDirectTransfer + CC : Alerting
19) RRC : uplinkDirectTransfer + CC : Connect
20) RRC : downlinkDirectTransfer + CC : Connect Acknowledge
21) < Voice Traffic >
< 06) RRC : RRC Connection Request >
rrcConnectionRequest
initialUE-Identity: imei (3)
imei: 15 items
Item 0
IMEI-Digit: 3
Item 1
IMEI-Digit: 5
Item 2
IMEI-Digit: 6
Item 3
IMEI-Digit: 4
Item 4
IMEI-Digit: 3
Item 5
IMEI-Digit: 2
Item 6
IMEI-Digit: 0
Item 7
IMEI-Digit: 5
Item 8
IMEI-Digit: 7
Item 9
IMEI-Digit: 9
Item 10
IMEI-Digit: 3
Item 11
IMEI-Digit: 4
Item 12
IMEI-Digit: 5
Item 13
IMEI-Digit: 3
Item 14
IMEI-Digit: 0
establishmentCause: emergencyCall (9)
protocolErrorIndicator: noError (0)
measuredResultsOnRACH
currentCell
modeSpecificInfo: fdd (0)
fdd
measurementQuantity: cpich-Ec-N0 (0)
cpich-Ec-N0: 43
v3d0NonCriticalExtensions
rRCConnectionRequest-v3d0ext
v4b0NonCriticalExtensions
rrcConnectionRequest-v4b0ext
accessStratumReleaseIndicator: rel-8 (4)
v590NonCriticalExtensions
rrcConnectionRequest-v590ext
.... 0... predefinedConfigStatusInfo: False
v690NonCriticalExtensions
rrcConnectionRequest-v690ext
ueCapabilityIndication: hsdch-edch (1)
domainIndicator: cs-domain (0)
cs-domain
csCallType: speech (0)
v6b0NonCriticalExtensions
rrcConnectionRequest-v6b0ext
v6e0NonCriticalExtensions
rrcConnectionRequest-v6e0ext
v770NonCriticalExtensions
rrcConnectionRequest-v770ext
mac-ehsSupport: true (0)
v7b0NonCriticalExtensions
rrcConnectionRequest-v7b0ext
v860NonCriticalExtensions
rrcConnectionRequest-v860ext
pre-redirectionInfo
.... .1.. supportEUTRA-FDD: True
.... ..0. supportEUTRA-TDD: False