This document is a summary of 2G; 2.5G; 2.75G and 3G
Security Level:
2008-4-22
2G 3G Handover
www.huawei.com
HUAWEI TECHNOLOGIES CO., LTD.
Huawei Confidential
Content 1. Constringent Transmit mode 2. Handover CS 3G to 2G 3. Handover CS 2G to 3G 4. Handover PS 3G to 2.5G 5. Handover PS 2.5G to 3G
Constringent Transmit Mode for UMTS
Handover flow include measurement control, measurement, measurement report, handover judgment and handover execution. Measurement for intersystem is very important
Constringent Transmit mode: measurement for Interfrequency and Inter-system
For FDD transmit mode of UMTS network, UE need to receive DL data from NODEB for whole the time. UE can’t receive signal from other frequency or other system. Constringent transmit mode is used as giving some idle timeslot to measure other frequency or other system
Constringent Transmit Mode for UMTS
One frame (10 ms)
Transmission gap available for inter-frequency measurements
Using Puncturing half reducing Spreading factor and High level schedule actualize transmit GAP
7 timeslot is the biggest idle length for each 10ms frame
When GAP span two radio frame, system using at least 8 timeslot as transmit data for each radio frame
Handover CS 3G to 2G
Handover include these steps
measurement control
measurement report
handover judgment
handover execution
If there is only one RF mode in one UE, it must use constringent mode to
measure the different system
If there are two RF mode in one UE, it can measure GSM network without
constringent mode
HO Process:
UE send a bad quality information to RNC
RNC originate a constringent transmit mode to measure 2G network
RNC originate a handover from UMTS to GSM after find a good quality
GSM neighbor cell
Handover flow for CS 3G to 2G
UE use measurement report of GSM get information of GSM (Rx_LEV. BSIC)
Handover CS 2G to 3G
For GSM handover to UMTS:
When there are UMTS neighbors for GSM cells, measurement control
information is sent in system information
UE measure the UMTS system information in idle timeslot then send it to BSC
BSC make a judgment of handover using the measurement report.
Because GSM is a TDMA system:
It can finish the UMTS’s measurement in idle timeslot
GSM needn’t support constringent mode .
Handover flow for CS 2G to 3G There is some judgment flow before handover using measurement report from UMTS system
Handover PS 3G to 2.5G UMTS to GRPS HO is data service HO from UMTS to GPRS; 1.
UE update the measurement report that UMTS cell work in bad quality
2.
RNC send RL RECONFIG PREPARE command to NODEB. Asking NODEB use constringent mode
3.
NODEB send RL RECONFIG READY information to RNC, when it constringent mode is prepared
4.
RNC send PHYSICAL CHANNEL RECONFIG information to UE. Asking UE use constringent mode
5.
RNC confirm UE had received the PHYSICAL CHANNEL RECONFIG information
，
send a RL RECONFIG COMMIT information to NODEB
，
tell NODEB the time of staring constringent mode 6.
UE send PHYSICAL CHANNEL RECONFIG COMPLETE information to RNC
7.
tell RNC that it had finished staring constringent mode
，
RNC send measurement control let UE begin to measure GSM system
Handover flow for PS 3G to 2.5G
RNC originate handover flow after judgment using measure report of GSM Network.
Handover flow for PS 3G to 2.5G
Handover flow for PS 2.5G to 3G
Intersystem Change is the same with CS handover .The difference is when RNC received measure report of UMTS system will send a cell change information to UE
