Call flows

1. GSM,GPRS,UMTS,HSDPA and
HSUPA Protocols and Call flow
By
Kiran Koona

2. Overview
1.GSM Protocols and Call flow
2.GPRS Protocols and Call flow
3.UMTS Protocols and Call flow
4.HSDPA and HSUPA Protocols.

3. GSM

4. GSM Architecture-Interfaces

7. Layer 1 Protocol
TDMA – Time Division Multiple Access
G.703 – ITU PCM frame structure
MTP – Message Transfer Part
Layer 2 Protocols
LAPDm Link Access Protocol D-channel-mobile
LAPD Link Access Protocol D-Channel
Layer 3 Protocols
RR – Radio Resource Management
MM – Mobility Management
CM – Connection management
BTSM – Base Transceiver Station Management
SCCP – Signalling Connection Control Part
BSSMAP – Base Station Subsystem
MAP-Mobile Application Part
DTAP – Direct Transfer Application Part
3-Layer Model
TUP , ISUP

8. Physical Layer
1.Txn of bits
2.Error detection and Correction
3.Interleaving
4.Burst Formating
5.Measurements
6.Power Control
7.Modulation and Demodulation
BTS-BSC: 64Kbps
BSC-MSC:2Mbps (32*64Kbps)

9. Physical Layer

10. Interfaces with Physical Layer

11. Layer-2: LAPDm and LAPD
1.Flow control
2.Sequence Numbering
3.Duplicate detection
4.Frame formatting

12. Layer-3: RRM
Protocols: RR, RSM, BSSAP.
1. Cell selection and Reselection  Control
2. Handover procedure
3. Establishing , maintaining, monitoring and releasing the channels
4. Monitoring and forwarding of radio connections
5. Introduction of encryption
6.Change in transmission mode ,Channel coding depending on
channel conditions Advise L1 and L2
7.MS level measurement commands control
8.Frequency redefinition Downlink Freq hopping
9.Broadcasting System Information  Downlink
10.Paging

13. RRM Messages

14. Layer-3:MM
Protocols : DTAP,MAP.
1.Authentication request/response
2.Ciphering Information/Commands from MSC
3.Abort from MSC Auth Failure
4.Normal location Updating request/response
5.Periodic location update
6.TMSI Reallocation Procedure
7.IMSI attach/detach
8.IMEI request/response

15. MM Messages

16. Layer-3:CM
1.Call control (CC) - manages call connections,
2.Supplementary service support (SS) - handles special services
3.Short message service support (SMS) - transfers brief texts.
CC:
Mobile-originating call establishment  Setup message
Mobile-terminating call establishment  Paging
Call clearing initiated by the network
Call clearing initiated by the Mobile
DTMF
SS:
Call Forwarding
Call waiting ,Call Hold and Conference
Multi Call
CLIP,CLIR ,COLP and COLR
SMS:

17. CM Messages

18. SS 7
To provide General purpose Signaling system to be used globally.
CCS , Out of Band
ITU-T Q.700 series.
Elements: SSP,STP and SCP.
Access Links: A to F
Analogy: MTP3 IP and SCCPTCP
SCCP: GTT, Ext MTP (Supports CL or CO)
Message Discrimination & distribution
TCAP: Query and Response (CL or CO )
MTP 3: Routing within SPC
MTP2: Node to node delivery

19. SS 7 Architecture
SSP, STP and SCP

20. SS 7 Logical Network

21. MAP
MAP messages are carried by TCAP when dealing with Database centre.
MAP Sessions: Open, Close. Message Types: Request, Response, Notification and
Confirmation.

22. GTT

23. GSM Call flow

24. GSM Logical Channels

25. IMSI Attach

26. Location Update

27. Authentication and Ciphering

28. Identity (IMSI) checking

29. Call Origination
2929

30. Call Clearing

31. IMSI Detach

32. MSRN Usage
Our HLR Knows where our Customer is,
Only our GMSC can inquire our HLR

34. GPRS

35. GPRS Architecture-Interfaces

36. GPRS Protocol Stack

38. Packet Fragmentation

39. MAC
1.MAC arbitrates access to the shared medium between
multiple MSs and GPRS network.
2.Uplink: Managing limited resourcesSlotted Aloha
3.Downlink: Queuing and Scheduling of access attempts.
4.Priority handling between data flows of one UE
5.Priority handling between UEs by means of dynamic
scheduling—Downlink
6.Channel mapping
7.Traffic Volume monitoring

40. RLC
1.SAR
2.Concatenation
3.Padding
4.Error Correction---CRC, ARQ (For AM)
5.In-Sequence delivery of SDUs
6.Duplicate detection
7.Flow control
8.Sequence number check---UM
9.Suspend/resume functionality
10.SDU discard

41. LLC
Provide a reliable logical link between MS and SGSN.
LLC messages are transparent to RAN.
Transmission in Asynchronous Disconnected Mode and
Asynchronous Balanced Mode
Ciphering.
Transfer of PDUs of Higher Layers
C-Plane: attach, authentication and PDP activation
U-Plane: carry actual data.
Can be AM or UM

42. SNDCP
• Transparent over BSS. Used only in U-Plane
•multiplexing of PDPs. Can be AM or UM
•compression of user data (including IP header compression) RFC 1154 & 2507
•segmentation of data packets to be passed to the LLC layer.

43. Frame Relay
Meshed N/W Frame Relay

44. Frame Relay
Speed up to 2 Mbps.
Simple.
Superseded by ATM

45. BSSGP
Transport both control and User data.
Provide the required QoS.
One-to-one mapping of BSSGP between SGSN and BSS.

46. BSSGP Data Frames

47. GTP
1.GTP-U and GTP-C.
2.Uses TCP for Reliable link
3.Uses UDP for non-Reliable link

48. IP, TCP and UDP
IP: IPv4 or IPv6. Datagram Service. Class full or Class less
Addressing.
TCP: Connection Oriented.
Ack ARQ. Sequence Number Checking.
Three-way handshake. Point-to-Point Add
Flow Control and Congestion Control.
UDP: Connection less.
Used for Delay Sensitive applications.
Supports Multicast Addressing.

49. GPRS Callflow

50. GPRS Logical Channels

51. GPRS Attach

52. PDP Context Activation

53. PDP

54. Data Transfer from MS

55. Data Transfer to MS

56. Web Access in GPRS

57. PDP Context Deactivation

58. Security

59. GPRS Detach

60. UMTS

61. Architecture-Interfaces

62. R99 Protocol Stack

63. Access Stratum

64. MAC
Logical to Transport Conversion
Mac-b located at Node-B
Mac-c/sh and Mac-d are at SRNC.

65. MAC functionalities
1.Mapping between logical channels and transport channels
2.Selection of appropriate TF (from the TFCS) for each Transport
Channel, depending on the instantaneous source rate
3.Priority handling between data flows of one UE
4.Priority handling between UEs by means of dynamic scheduling—
Downlink
5.Identification of UEs on common transport channels
6.Multiplexing/demultiplexing of higher layer protocol data units
(PDUs)
7.Traffic volume monitoring—Down link
8.Dynamic Transport Channel type switching
9.Ciphering—RLC (TM)
10.Access Service Class (ASC) selection for RACH transmission

66. RLC
1.Transparent mode (Tr) , Unacknowledged Mode (UM) or
Acknowledged Mode (AM)
2.Tr and UM RLC entities are defined to be unidirectional, whereas the
AM-mode entities are described as bidirectional
3.Tr—Voice Call Video Call, UM—VOIP, Streaming

67. RLC functionalities
1.Segmentation and reassembly
2.Concatenation
3.Padding
4.Transfer of user data
5.Error correction----ARQ
6.In-sequence delivery of higher layer PDUs
7.Duplicate detection
8.Flow control
9.SN check (unacknowledged data transfer mode).
10.Ciphering is performed in the RLC layer for acknowledged and
unacknowledged modes.
11.Suspend/resume function for data transfer

68. RLC Dataflow

69. RRC
1.Broadcast of system information
2.Paging and notification
3.Initial cell selection and reselection
4.Establishment, maintenance and release of an RRC
connection
5.Establishment and release of Radio bearers
6.Control of ciphering
7.Integrity protection of signalling messages
8.UE measurement reporting and control of the reporting
9.RRC connection mobility functions
10.Support of SRNS relocation
11.Support for downlink outer loop power control in the UE
12.Open-loop power control
13.CBS-related functions (BMC)
14.Handovers---preparation and execution
15.Control of requested QoS
16.Routing of Higher layer PDUs (Direct transfer)
17.MBMS control

70. RRC States

71. BMC
BMC: Broadcast/Multicast Control Protocol
SMS-CB service
1.Storage of CB
2.Traffic volume monitoring and radio resource request for
CBS
3.Scheduling of BMC messages
4.Transmission of BMC messages to UE

72. PDCP
PDCP: Packet Data Convergence Protocol
1.PS Domain
2.PDCP contains compression methods, which are needed to get
better spectral efficiency over radio interface.
3.IP Packet header compression. Eg: 40 bytes for IPv4 and at least
60 bytes for IPv6. (RFC 2507)
4.Transfer of user data

73. Non Access Stratum

74. Protocol Interworking architecture
Transport : Carry Signaling and User data.
Radio N/W : Establish, maintain and Release RB.
System: Create Communication with Core network.

75. Transport Network protocols

76. Radio network protocols

77. System network protocols

78. UMTS Call flow

79. R99 Channels

80. Basic Model of Network
transactions

81. RRC Connection Setup
RRC Connection CCCH (By passing Node-B)

82. Paging
Paging Type 1 through  PCCH
Paging Type-2 through DCCH
RRC Connection CCCH

83. Authentication and Security Control
DCCH Channel and MM messages

84. Transaction setup and RAB allocation
(CS)
Setup : DCCH Call Proceeding: DTCH

85. Transaction setup and RAB allocation
(PS)

86. Transaction Clearing with RAB release

87. RRC Connection release

88. LU in CS domain

89. RU in PS domain

90. HSDPA and HSUPA

91. R99 RRM Architecture

92. HSDPA and HSUPA RRM Architecture

93. New Functionalities

94. HSDPA and HSUPA Channels

95. R99 Protocol Stack

96. HSPA Protocol stack

97. HSDPA Protocol Stack

98. HSDPA user plane Protocol Architecture
Fast Node-B Scheduling
H-ARQ ,Incremental Redundancy
Soft Buffer at Node-B and UE
Retransmission at N/W borders  No Soft Handover

99. HSUPA Protocol Stack

100. HSUPA user plane protocol Architecture
Mac-es/e : Uplink Scheduling
Mac-e: Hybrid ARQ , Buffer
Mac-es : In-sequence delivery (Soft Handover)
RLC re transmissions may take place if Physical layer re
transmissions is exceeded initiated by RNC.

101. References
1.3G TS 25.321, MAC Protocol Specification.
2.3G TS 25.322, RLC Protocol Specification.
3.3G TS 25.323, PDCP Protocol Specification
4.3G TS 25.331, RRC Protocol Specification
5.3G TS 25.324, Broadcast/Multicast Control Protocol (BMC)
Specification
6.3G TS 25.302, Services Provided by the Physical Layer
7. 3GPP TS 25.331 RRC specification
8.3GPP TS 25.413 RANAP
9.3GPP TS 25.423 RANSAP
10.3GPP TS 25.433 NBAP
11.GSM.System.Engineering.-.Artech BOOK, by Asha Mehrotra.
12.GPRS BOOK-MC-HIL by R.J. Bates.
13.WCDM for UMTS-Wiley –H.Holma and A.Toskala
14.SS7 –MC-HILL by Travel Russel

102. Datagram

103. Virtual Circuit