Cell Re-Selection

Radio Resources Operating Modes Definitions (Class B assumed)
• Class B Mobile is able to handle CS and PS Traffic but not at the same time
• Packet Switching Modes
– Idle (TBF not established)
– Transfer (TBF exists on one or more radio channels)
• Circuit Switching Modes
– Idle (no RR connection)
– Dedicated (RR exists)

Different MS behavior with Packet BCCH 

Without allocated PBCCH
The GPRS MS listen to the GSM BCCH and PCH
•The GPRS MS will use the GSM CS PCH, RACH and AGCH
With allocated PBCCH
The GPRS MS reads SI on BCCH to find PBCCH
•Now the GPRS MS only listens on PBCCH and PPCH
•GPRS dedicated Packet System Information sent on PBCCH
•The  PPCH, PRACH and PAGCH are used
The PBCCH timeslot must be a dedicated PDCH in R8.

GPRS Cell (Re-) Selection – No PBCCH used (III)
GPRS MS re-selects a new cell if any of the following criteria is satisfied:
• C1 for the serving cell falls below 0 for a 5 seconds
• C2 of non-serving cell exceeds C2 value of the serving cell for the period of 5 seconds.
• Serving cell becomes barred
• MS has unsuccessfully tried to access network the allowed number of times
• MS dettects a downlink signalling failure

GPRS Cell (Re-) Selection –PBCCH used
GPRS MS re-selects a new cell if any of the following criteria is satisfied:
• C1 for the serving cell falls below 0
• The best non-serving cell does have the highest value of C32 among:
– All cells with the highest priority fulfilling C31 criterion
– All cells, if no cells fulfill C31 criterion
• Serving cell becomes barred
• MS has unsuccessfully tried to access network the allowed number of times
• MS dettects a downlink signalling failure

Physical Channel Structure_part #2

Physical Channel Structure_part #1

GPRS Radio Network Configuration
• Physical Channel Structure
• Cell Re -Selection
• GPRS Channel Allocation
• Radio Network Features
• Cell planning
• GPRS Cell Parameters and BSC Properties and SGSN Parameters
• EGPRS Radio Network Enhancements in R9.1

GPRS Radio Network
Configuration
Part 1: Physical Channel Structure
Packet Data Logical Channels
• PBCCH – broadcast of system information (DL)
• PCCCH –common control signalling
– PRACH – uplink packet transfer initiation (UL)
– PAGCH – resource assignemnt (DL)
– PPCH – paging for either PS or PS&CS (DL)
– PNCH – PTM – M, Multicast (DL)
• PDCCH
– PACCH – MS- specific signalization (UL & DL)
– PTCCH/U – MS- specific timing advance information (UL)
– PTCCH/D – timing advance information for group of MSs (DL)
• PDTCH – end-user data traffic
– PDTCH/U – end- user traffic in uplink direction (UL)
– PDTCH/D – end- user traffic in downlink direction (DL)

GPRS Multi-Frame Structure
• One TDMA Frame (F) consists of 8 Time Slots (TS)
• 4 Consecutive TDMA Frames (F) are groupped into one TDMA Block (B)
• 12 Blocks + 2 Idle TDMA Frames+ 2 TDMA Frames used for PTCCH
consisting 52 Multi- Frame structure

GPRS Multi-Frame Structure (MPDCH)
• PBCCH is indicated on BCCH channel
• Different structure for UL/DL
• Mapping of channels are controlled by PBCCH parameters
• In downlink case first blocks can be reserved for PRACH, other are
used for PDTCH and PACCH channels

GPRS Multi-Frame Structure (PDTCH)
• Very similar in UL and DL
• Almost all Blocks used for PDTCH & PACCH
• Idle and PTCCH can be used for signal measurements and BSIC
identification

to be continue....