Prepared by Abdulrahman Fady
L3 Messages is the messages transferred between MS and Network (BSC or MSC ) to control the MS behavior in idle mode and in dedicated mode as well as tell MS when to do Location update
L3 Messages are UL and DL and conveyed on Control channels BCCH PCH SDCCH SACCH FACCH
L3
Messages
CM
SI
RR
MM
What are system Information Messages Downlink messages
sent on BCCH channel or SACCH channel
Used to inform MS by all the needed information to enable it to do its operations in normal way
SI messages transmitted periodically from BTS and MS reads them every 30 sec for serving cell and every 5 minutes for six strongest cells
There are a lot of SI types e.g. SI type 1, SI type 2
Direction : DL
Channel : BCCH
Contents BCCH Frequency
Available frequencies
RACH Control parameters as MAXRET
Cell Barring
Emergency
Direction : DL
Channel : BCCH
Contents BCCH frequency
MAXRET
Call re-establishment control
NCC permitted range
Cell Barring
Direction : DL
Channel : BCCH Contents
PLMN ID (MCC & MNC) Cell ID LAC MFRMS
AGBLK
Mapping Method
ATT
T3212 RL_timeout
Selection Parameters ACCMIN MAX-TX-PWR-UL CRH
Cell reselection CRO PT TO
Half rate support SI scheduling
Direction : DL
Channel : BCCH
Contents
PLMN ID (MCC & MNC)
Cell ID
LAC
Cell Selection Parameters
Cell Reselection Parameters
Direction : DL
Channel : BCCH
Contents
Other Band BA list
Direction : DL
Channel : BCCH
Contents
Same Band BA list
Direction : DL
Channel : BCCH
Contents
GPRS Information
EGPRS Supported
Power control
Network Mode
Direction : DL Channel : SACCH Contents
GPRS Information Cell ID LAC PLMN ID RL timeout DTX info Band
Direction : DL
Channel : SACCH
Contents
BA list
Direction : DL
Channel : SACCH
Contents
Part from Active BA list
Direction : DL
Channel : SACCH
Contents
Part from Active BA list
Multi band reporting
Immediate Assignment SDCCH assignment during Call Setup
Measurement Report MS should report 6 strongest neighbors cells to BSC
Handover Command BSC instruct the MS to do HO to certain Cell
Handover Access MS starts HO process
Handover Complete Message sent after HO completed Successfully
Direction : DL
Channel : AGCH
Contents
Inform MS about SDCCH that will be used in call Setup
Direction : UL
Channel : SACCH
Contents
Six strongest neighbors
Direction : DL
Channel : SACCH
Contents
Instruct the MS to handover to a certain cell by sending its information
BCCH
BSIC
MAIO /HSN
Direction : UL
Channel : FACCH
Contents
MS tries to access the new cell using this message
Direction : UL
Channel : FACCH
Contents
MS inform the network that the HO has been completed successfully