LTE 测量事件 LTE_measurement_events

zcybear

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Measurement Event Comparison
While sitting in a colleague’s class this week we were discussing the UMTS measurement event types.  I thought it might be good to do a comparison of UMTS’s measurement events with the measurement events in LTE. There are a couple of key differences between the two. The first is that UMTS supports a soft handover and LTE does not. That is important in looking at this comparison as there is no active set in LTE. The second difference is that LTE does not highlight the differences between intra-frequency measurements and inter-frequency measurements as strongly as UMTS does. The following table gives a comparison and comments on how the LTE measurements compare with UMTS.
I hope it is helpful.
Thanks,
Chris

LTE Measurement Events and Description        UMTS Measurement Events and Description        Comments
Event A1 - Serving becomes better than threshold        e2f  - The estimated quality of the currently used frequency is above a certain threshold        In LTE this may be used to stop looking for a cell on a different frequency or technology, as e2f is used in UMTS.
Event A2 - Serving becomes worse than threshold        e2d  - The estimated quality of the currently used frequency is below a certain threshold        In LTE this may be used to start looking for a cell on a different frequency or technology, as e2d is used in UMTS.
Event A3 - Neighbor becomes offset better than serving        e1a - A Primary CPICH enters the reporting range        This comparison is a bit of a stretch. The reason I have equated them is because in both cases a neighbor should be considered for a handover, either soft or hard depending on the technology.
Event A4 - Neighbor becomes better than threshold        e1e - A Primary CPICH becomes better than an absolute threshold         
Event A5 - Serving becomes worse than threshold1 and neighbor becomes better than threshold2        e2b - 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        This comparison is good for saying that the current cell is below an absolute threshold and the new cell is above a threshold. This would mean that the current cell is not good enough and the new one is good, which is a good reason to do a hard handover (in either technology).
Event B1 - Inter RAT neighbor becomes better than threshold        e3c - The estimated quality of other system is above a certain threshold         
Event B2 - Serving becomes worse than threshold1 and inter RAT neighbor becomes better than threshold2        e3a - 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        This comparison is good for saying that the current cell is below an absolute threshold and the new cell on a different technology is above a threshold. This would mean that the current cell is not good enough and the new one is good, which is a good reason to do a hard handover to the new technology.