BCCH System Information - Lecture - Mobile Computing, Lecture notes of Mobile Computing

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BCCH System Information

The information broadcast may be grouped in the following

classes:

• information giving unique identification of the current

network, location area and cell;

• information used for candidate cell measurements for

handover and cell selection procedures;

• information describing the current control channel

structure;

• information controlling the random access channel

utilization;

• information defining different options supported within the

cell; and

• information about the length of the part of the message

belonging to the phase 1 protocol.

BCCH System Information

SYSTEM INFORMATION TYPE 1

SYSTEM INFORMATION TYPE 2

SYSTEM INFORMATION TYPE 2bis SYSTEM INFORMATION TYPE 2ter SYSTEM INFORMATION TYPE 3 SYSTEM INFORMATION TYPE 4 SYSTEM INFORMATION TYPE 5 SYSTEM INFORMATION TYPE 5bis SYSTEM INFORMATION TYPE 5ter SYSTEM INFORMATION TYPE 6 SYSTEM INFORMATION TYPE 7 SYSTEM INFORMATION TYPE 8 SYSTEM INFORMATION TYPE 9 SYSTEM INFORMATION TYPE 10 SYSTEM INFORMATION TYPE 11 SYSTEM INFORMATION TYPE 12 SYSTEM INFORMATION TYPE 13 SYSTEM INFORMATION TYPE 14 SYSTEM INFORMATION TYPE 15

BCCH System Information Types

This message is sent on the BCCH by the network to all mobile

stations within the cell giving information of control of the RACH

and of the cell allocation.

Special requirements for the transmission of this message apply.

This message has a L2 Pseudo Length of 21.

Message type: SYSTEM INFORMATION TYPE 1

Significance: Dual

Direction: Network to mobile station

SYSTEM INFORMATION TYPE 1

IEI Information Type / Reference Presence Format Length Element L2 pseudo length L2 pseudo length M V 1 RR management Protocol Discriminator M V 1/ Skip Indicator Skip Indicator M V 1/ System Information Message Type M V 1 Type 1 Msg. Type Cell Channel Cell Channel M V 16 Description Description RACH Control RACH Control M V 3 Parameter Parameter SI 1 Rest Octets SI 1 Rest Octets M V 1

SYSTEM INFORMATION TYPE 1

SYSTEM INFORMATION TYPE 1 message content

____[ 97 ] ___[ 20:27:44, 454 ] ___ [ DOWN ] ___ [ BCCH ] ____________ 06 19 00 00 00 02 00 10 00 00 00 00 00 00 00 00 00 00 a5 00 00 06 0------- Direction from : Originating site -000---- Transaction ID : 0 ----0110 Protocol Discrim : radio resource management message 19 0001100 1MESSAGE TYPE : SYSTEM INFORMATION TYPE 1

: Cell Channel Description 00 00------ Format Type : Bit Map 0 format --00---- 2 spare bit : 0 02 ------1- Cell Allocation : ARFCN 98 10 ---1---- Cell Allocation : ARFCN 85 :RACH Control Parameters

a5 10------ Max. of retransmiss : 4 --1001-- slots to spread TX : 12 ------0- The cell is barred : no -------1 Call reestab.i.cell : not allowed 00 00000--- Acc. Contr. C1. 11-15 : 0 Access allowed., 1 Access not allowed -----0-- Emergency Call EC 10 : allowed ------00 Acc. Contr. Cl. 8 -9 : 0 Acess allowed., 1 Access not allowed. 00 00000000 Acc. Contr. Cl. 0 -7 : 0 Access allowed., 1 Access not allowed

The message SYSTEM INFORMATION TYPE 2

consists of the neighbouring cells to be monitored,

the permitted NCC and the declared rules for

random access.

The system information messages on the BCCH

broadcast the list of authorized access classes and

authorized special access classes in the system

information messages, and whether emergency calls

are allowed in the cell to all mobile stations or only to

the members of authorized special access classes.

SYSTEM INFORMATION TYPE 2

____[ 8 ] ___[ 12:02:42, 309 ] ___ [ DOWN ] ___ [ BCCH ] ____________ 06 1a 10 00 00 00 00 10 00 00 00 00 00 c0 20 95 00 00 08 a5 00 00 06 0------- Direction from : Originating site -000---- Transaction ID : 0 ----0110 Protocol Discrim : radio resource management messages 1a 00011010 MESSAGE TYPE : SYSTEM INFORMATION TYPE 2 10 --0----- Extension Indicator : The IE carries the complete BA ---1---- BCCH alloc. Sequ.num : 1 10 ---1---- BCCH alloc. RF chan. : 85 c0 1------- BCCH alloc. RF chan. : 40 -1------ BCCH alloc. RF chan. : 39 20 --1----- BCCH alloc. RF chan. : 30 95 1------- BCCH alloc. RF chan. : 24 ---1---- BCCH alloc. RF chan. : 21 -----1-- BCCH alloc. RF chan. : 19 -------1 BCCH alloc. RF chan. : 17 08 ----1--- BCCH alloc. With NCC = 3 is permitted for monitoring a5 10------ Max. of retransmiss : 4 --1001-- 12 slots used to spread TX ------0- The cell is barred : no -------1 Call reestablishment in cell is not allowed 00 -----0-- Emergency call EC 10 : allowed 00000--- acc ctrl class 11 – 15 : 0/1 access permitted/forbidden ------00 acc ctrl class 8 – 9 : 0/1 access permitted/forbidden 00 00000000 acc ctrl class 0 – 7 : 0/1 access permitted/forbidden

• NCC
  • NCC

IEI Information Type / Reference Presence Format Length Element L2 Pseudo Length L2 Pseudo Length M V 1 RR management Protocol Discriminator M V 1/ Skip Indicator Skip Indicator M V 1/ System Information Message Type M V 1 T Type 2bis Msg. Type Extended BCCH Neighbour Cell M V 16 Frequency List Description RACH Control RACH Control M V 3 Parameters SI 2bis Rest SI 2bis Rest M V 1 Octets Octets

SYSTEM INFORMATION TYPE 2bis

SYSTEM INFORMATION TYPE 2bis message content

SYSTEM INFORMATION TYPE 2ter

This message is sent optionally on the BCCH by the network to

all mobile stations within the cell giving information on the

extension of the BCCH allocation in the neighbour cells.

Special requirements for the transmission of this message apply.

A mobile station that supports either:

only the primary GSM band P-GSM 900, or

only the DCS 1800 band may ignore this message.

This message has a L2 pseudo length of 18. This message

may be sent by the network with either a L2 pseudo length of

18 or some other value. A mobile station that does not ignore

this message shall not discard the message due to a received

L2 pseudo length different from 18.

SYSTEM INFORMATION TYPE 3

This message is sent on the BCCH by the network giving

information of control on the RACH, the location area

identification, the cell identity and various other information

about the cell.

Special requirements for the transmission of this message

apply. This message has a L2 Pseudo Length of 18.

The message SYSTEM INFORMATION TYPE 3

The Information elements of SYS INFO 3

The first Information Element in the message SYSTEM INFORMATION TYPE 3 describes the Cell Identity (the number of the BTS) consisting of two bytes.

The second IE, the Local Area Identification consists of the Country Code (404 for India; the Network Code 01 is the Operator Airtel (D1)) and the IDs of the MSC and the BSC.

The third IE represents the Control Channel Description.

• IMSI Attach means the Mobile registers to the VLR whilst logging into the network and deregisters from the VLR when releasing its channel. A user calling for that mobile therefore knows at once whether or not the mobile is logged in.
• The Number of blocks reserved for access grant specifies how many of the Paging Channels can be used for network access.

SYSTEM INFORMATION TYPE 3