Traffic&Redesign

LCC Pakistan

Objective Call setup,Mobility&Integrity is a Key of Optimization

Traffic&Redesign

2

LCC Pakistan

Outline GSM Protocol Architecture for Signaling International Signaling relation via ISDN GSM Interface & Layers Function Call setup Overview Key points in Call Setup. Explanation of each point with layer 3&2 message & logical channels. Question &Answers3LCC Pakistan

Traffic&Redesign

GSM Protocol Architecture for Signaling

Traffic&Redesign

4

LCC Pakistan

GSM Signaling Network Continue

Traffic&Redesign

5

LCC Pakistan

International Signaling relation via ISDN

Traffic&Redesign

6

LCC Pakistan

SS7 Signaling Architecture

Traffic&Redesign

7

LCC Pakistan

SS7 Layer in GSM Network

Traffic&Redesign

8

LCC Pakistan

SS7 Layers in GSM Network

Traffic&Redesign

9

LCC Pakistan

SS7 Layers in GSM Network

Traffic&Redesign

10

LCC Pakistan

SS7 Layers in GSM Networky Mobile Application Part (MAP)

Mobile-specific extension of C7 standard. All messages exchanged between NSS Elements (MSC,HLR,VLR) A connectionless transport service provided by the SCCP Provides core functionality to support roaming Allows its users to access other users via worldwide C7/SS7 network Logical signalling connection between MSC and MS to support Layer 3 (MM/CM) message transfers Uses reduced set of C7 signalling instructions Routes messages via STPs C7 protocols responsible for routing and transport of signalling messages

y Transaction Capabilities Application Part (TCAP)

y Signalling Connection Control Part (SCCP)

y Message Transfer Part (MTP)

Traffic&Redesign

11

LCC Pakistan

SS7 Layers in GSM Network

Traffic&Redesign

12

LCC Pakistan

GSM Protocol Summery

Traffic&Redesign

13

LCC Pakistan

GSM Interfaces & Layers

Um Interface

Abis Interface

Other Interfaces

GSMA Interface E Interface B,C Interface

Traffic&Redesign

14

LCC Pakistan

A Interface

Traffic&Redesign

15

LCC Pakistan

A InterfaceBSSMAP - deals with procedures that take place logically between the BSS and MSC, examples : Trunk Maintenance, Ciphering, Handover, Voice/Data Trunk Assignment DTAP - deals with procedures that take place logically between the MS and MSC. The BSS does not interpret the DTAP information, it simply repackages it and sends it to the MS over the Um Interface. examples: Location Update, MS originated and terminated Calls, Short Message Service, User Supplementary Service registration, activation, deactivation and erasure

Traffic&Redesign

16

LCC Pakistan

A Interface

Traffic&Redesign

17

LCC Pakistan

A Interface

Traffic&Redesign

18

LCC Pakistan

Abis Interface

Traffic&Redesign

19

LCC Pakistan

Abis Interfacey Messages exchanges between the BTS and BSC.

Traffic exchanges Signaling exchanges y Physical access between BTS and BSC is PCM digital links of E1(32) or T1(24) TS at 64kbit/s. y Speech: Conveyed in timeslots at 4X16 kbit/s y Data: Conveyed in timeslots of 4X16 kbit/s. The initial user rate, which may be 300, 1200, is adjusted to 16 kbit/s

Traffic&Redesign

20

LCC Pakistan

Abis InterfaceLevel 1-PCM transmission (E1 or T1) Speech encoded at 16kbit/s and sub multiplexed in 64kbit/s time slots. Data which rate is adapted and synchronized. Level 2-LAPD protocol Radio Signaling Link (RSL) Operation and Maintenance Link (OML). Level 3-Application Protocol Radio Subsystem Management (RSM) Operation and Maintenance procedure (OAM)

Traffic&Redesign

21

LCC Pakistan

Abis Interface

Traffic&Redesign

22

LCC Pakistan

LAPD Message

Traffic&Redesign

23

LCC Pakistan

LAPD Message..y The length is limited to 260 octets of information. y LAPD has the address of the destination terminal, to

identify the TRX, since this is a point to multipoint interface. y Each TRX in a BTS corresponds to one or several signaling links. These links are distinguished by TEI (Terminal Equipment Identities).y SAPI=0, SAPI=3, SAPI=62 for OAM.

Traffic&Redesign

24

LCC Pakistan

Um Interfacey Level 1-Physical

TDMA frame Logical channels multiplexing y Level 2-LAPDm(modified from LAPD) No flag No error retransmission mechanism due to real time constraints y Level 3-Radio Interface Layer (RIL3) involves three sub layers RR: paging, power control, ciphering execution, handover MM: security, location IMSI attach/detach CM: Call Control(CC), Supplementary Services(SS), Short Message Services(SMS),

Traffic&Redesign

25

LCC Pakistan

Layer1 Signaling

Traffic&Redesign

26

LCC Pakistan

Layer 2 Signaling

Traffic&Redesign

27

LCC Pakistan

LAPDm Message In LAPDm the use of flags is avoided. LAPDm maximum length is 21 octets of information. It makes use of more bit to distinguish last frame of a message. No frame check sequence for LAPDm, it uses the error detecting performance of the transmission coding scheme offered by the physical layer

Traffic&Redesign

28

LCC Pakistan

LAPDm Message.y The acknowledgement for the next expected frame in the indicator N(R ). y On radio interface two independent flows(one for signaling, and one for y y y y

SMS) can exist simultaneously. These two flows are distinguished by a link identifier called the SAPI(service access point identifier). LAPDm SAPI=0 for signaling and SAPI=3 for SMS. SAP1=0 for radio signaling, SAPI=62 for OAM and SAPI=63 for layer 2 management on the Abis interface. There is no need of a TEI, because there is no need to distinguish the different mobile stations, which is done by distinguishing the different radio channels.

Traffic&Redesign

29

LCC Pakistan

Layer 3 Signaling

Traffic&Redesign

30

LCC Pakistan

Layer3 Signaling Message Format at air Interface

Traffic&Redesign

31

LCC Pakistan

Protocol Discriminator

Traffic&Redesign

32

LCC Pakistan

Transaction Identifier

Traffic&Redesign

33

LCC Pakistan

Message Type

Traffic&Redesign

34

LCC Pakistan

Traffic&Redesign

35

LCC Pakistan

Traffic&Redesign

36

LCC Pakistan

Information Element

Traffic&Redesign

37

LCC Pakistan

Measurement Report

Traffic&Redesign

38

LCC Pakistan

Layer 3 Function

Traffic&Redesign

39

LCC Pakistan

RR Management

Traffic&Redesign

40

LCC Pakistan

Mobility Management

Traffic&Redesign

41

LCC Pakistan

Connection Management

Traffic&Redesign

42

LCC Pakistan

RR Massage, Channel & MT Code

Traffic&Redesign

43

LCC Pakistan

MM Massage

Traffic&Redesign

44

LCC Pakistan

CM Message

Traffic&Redesign

45

LCC Pakistan

Call Setup Overview MS Idle Mode Behavior Call setup signaling flow with Layer2&Layer3 explanation Handover signaling flow Location updated signaling Flow

Traffic&Redesign

46

LCC Pakistan

MS Idle Mode Behavior

Traffic&Redesign

47

LCC Pakistan

Idle Mode Measurements..explain in call Setup

Traffic&Redesign

48

LCC Pakistan

Call Setup Signaling Flow

Traffic&Redesign

49

LCC Pakistan

Call Setup Signaling Flow

Traffic&Redesign

50

LCC Pakistan

Call Setup With Counters

Traffic&Redesign

51

LCC Pakistan

Paging Typesy Paging locates MS to cell Level for call

routing

y Three paging message types:

Type 1 - 2 MSs using IMSI/TMSI Type 2 - 3 MSs (1xIMSI, 2xTMSI) Type 3 - 4 MSs using TMSI onlyy Paging message requires 4 bursts (1

CCCH block)

y Paging messages may be stored at BSS y Transmitted on PCH y If DRX is implemented MS listens only

to allocated paging group

Traffic&Redesign

52

LCC Pakistan

Timers involved in Call Process

Traffic&Redesign

53

LCC Pakistan

Traffic&Redesign

54

LCC Pakistan

Traffic&Redesign

55

LCC Pakistan

Layer2&3 involved in Call setup

Traffic&Redesign

56

LCC Pakistan

Call Setup Measurements Layer3 RR Management Message MM Management Message CM Management Message

Layer2 RR-RSP I-CMD SABM-CMD UA-RSP DISC-CMD Call Setup Call Establishment Call End

Traffic&Redesign

57

LCC Pakistan

Layer3 Message. RR Management Message

Traffic&Redesign

58

LCC Pakistan

RR Paging Message StructureProtocol Discriminator

The Channel Field (bits 1-2 of octet 2) indicates the further combination of channel which will be needed. It is coded as follows

Traffic&Redesign

59

LCC Pakistan

RR-Paging MessagePaging Request Type1

Channel Needed To indicate what type of channel is required for the transaction linked to the paging procedure. First Channel 00 Any channel 01 SDCCH 10 TCH/F 11 TCH/H or TCH/F Second Channel Same as first channel

Page mode To control the action of MS belonging to the paging subgroup corresponding to the paging subchannel. Page Mode 00 Normal Paging 01 Extended Paging 10 Paging Re organisation 11 Same as before

Mobile Identity To provide either the IMSI, the (P) TMSI but notthe IMEI bases paging. IMSI