RRC reporting events in WCDMA, UMTS

RRC Reporting events or Handover events are sent from RBS or UE to trigger the different handover procedures in the RNC. The genertion of handover events depend on the different RF parameters and thresholds.

event 1A: A Primary CPICH enters the reporting range; addition of a radio link.
event 1B: A primary CPICH leaves the reporting range; removal of a radio link.
event 1C: A non-active primary CPICH becomes better than an active primary CPICH; replacement of the worst cell in AS.
event 1D: Change of best cell
event 1E: A Primary CPICH becomes better than an absolute threshold
event 1F: A Primary CPICH becomes worse than an absolute threshold
event 1G: Change of best cell (TDD)
event 1H: Timeslot ISCP below a certain threshold (TDD)
event 1I: Timeslot ISCP above a certain threshold (TDD)

Event 2a: Change of best frequency
Event 2b: The estimated quality of the currently used frequency is below a certain threshold and the estimated quality of a non-used frequency is above a certain threshold; handover to inter-freq neighbors
Event 2c: The estimated quality of a non-used frequency is above a certain threshold
Event 2d: The estimated quality of the currently used frequency is below a certain threshold; start compressed mode to measure inter-freq WCDMA or GSM neighbors.
Event 2e: The estimated quality of a non-used frequency is below a certain threshold
Event 2f: The estimated quality of the currently used frequency is above a certain threshold; stop compressed mode & stop measure inter-freq WCDMA or GSM neighbors

Event 3a: The estimated quality of the currently used UTRAN frequency is below a certain threshold and the estimated quality of the other system is above a certain threshold; handover to GSM neighbors
Event 3b: The estimated quality of other system is below a certain threshold
Event 3c: The estimated quality of other system is above a certain threshold
Event 3d: Change of best cell in other system

event 4 A: Transport Channel Traffic Volume becomes larger than an absolute threshold
event 4 B: Transport Channel Traffic Volume becomes smaller than an absolute threshold

event 5A: A predefined number of bad CRCs is exceeded

event 6A: The UE Tx power becomes larger than an absolute threshold; start compressed mode
event 6B: The UE Tx power becomes less than an absolute threshold; stop compressed mode
event 6C: The UE Tx power reaches its minimum value
event 6D: The UE Tx power reaches its maximum value
event 6E: The UE RSSI reaches the UE’s dynamic receiver range
event 6F: The UE Rx-Tx time difference for a RL included in the active set becomes larger than an absolute threshold
event 6G: The UE Rx-Tx time difference for a RL included in the active set becomes less than an absolute threshold

Event 7a: The UE position changes more than an absolute threshold
Event 7b: SFN-SFN measurement changes more than an absolute threshold
Event 7c: GPS time and SFN time have drifted apart more than an absolute threshold

For details, see 3GPP TS 25.331 – Radio Resource Control (RRC) protocol specification.

Mohit Kumar

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