Wednesday, May 19, 2010

Measurement report UMTS and LTE

Measurement report 3G

Two types of Measurement reporting is possible in 3G

1. Periodic

2. Event triggered

Measurement reporting parameters for both Periodic and Event triggered are set through system information.

Measurement report is send by the UE if a specific condition fulfilled.

To set the reporting condition, parameters are set in the system information 11 for idle state and system information 12 for connected state. If the parameters are not set in system information, it could be send through Measurement control.

Following are the different measurement reporting that UE can Perform:-

1. Intra-frequency measurements:

Parameter: - CPICH Ec/No, CPICH RSCP, pathloss

Event 1a:
A Primary CPICH enters the reporting range
Event 1b:
A Primary CPICH leaves the reporting range
Event 1c:
A non-active primary CPICH becomes better than an active primary CPICH
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

2. Inter-frequency measurements:

Parameter :- CPICH Ec/No, CPICH RSCP

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.
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
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

3. Inter-RAT measurements:

Parameter: - GSM carrier RSSI

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.
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

4. Traffic Volume Measurements

Parameter: - total buffer occupancy (BO) of RLC buffer, average of BOs, variance of BOs

Event 4a:
Transport Channel Traffic Volume becomes larger than an absolute threshold
Event 4b:
Transport Channel Traffic Volume becomes smaller than an absolute threshold

5. Quality measurements:

Parameter: - BLER (transport channel block error rate)

Event 5a:
A predefined number of bad CRCs are exceeded

6. UE internal measurements:

Parameter: - UTRA carrier RRSI (intra or interfrequency), UE Transmitted power, UE Rx-Tx Time difference

Event 6a:
The UE Tx power becomes larger than an absolute threshold
Event 6b:
The UE Tx power becomes less than an absolute threshold
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:
(FDD) The UE Rx-Tx time difference for a RL included in the active set becomes larger than an absolute threshold
(1.28 Mcps TDD): The time difference indicated by TADV 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

7. Positioning measurements:

Parameter: - UE GPS timing, Synchronization measurements SFN-SFN, SFN-CFN, GSM carrier observed time difference

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

Event 7d: GANSS time and SFN time have drifted apart more than an absolute threshold

Measurement reports in LTE

1. Event A1 (Serving becomes better than threshold)

2. Event A2 (Serving becomes worse than threshold)

3. Event A3 (Neighbor becomes offset better than serving)

4. Event A4 (Neighbor becomes better than threshold)

5. Event A5 (Serving becomes worse than threshold1 and neighbor becomes better than threshold2)

6. Event B1 (Inter RAT neighbor becomes better than threshold)

7. Event B2 (Serving becomes worse than threshold1 and inter RAT neighbor becomes better than threshold2)

Measurement report UMTS and LTE comparison

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.

6 comments:

  1. Thanks, this is clear and concise

    ReplyDelete
  2. Where is these defined in the specifications ?

    ReplyDelete
  3. 25.331 (UMTS) and 36.331 (LTE)

    ReplyDelete
  4. Thanks so much for the quick reference

    ReplyDelete
    Replies
    1. Hi Man
      You should know this events.

      Arturo B

      Delete
  5. quickie meas cntrl repo events and helpful

    ReplyDelete