How eNodeB decide among gap0 and gap1?

4G LTE
1

Query to Ericsson LTE experts:
There is parameter measurement gap allowed having value true or false .
What is value configured for this parameter in network?
If value is true then how gap value decided by eNodeB among gap0, gap1?

2

Its is configured by internal SC.
No direct parameter.

3

Thanks @Vicky. I’ve seen parameter measurement gap allowed. Let me check description.

4

The UE needs measurement gaps to perform measurements when it cannot measure the target carrier frequency while simultaneously transmitting/receiving on the serving cell.

In the case of LTE, the UE needs measurement gaps in order to perform inter-frequency and inter-RAT measurements.

Typical LTE gap length is 6 ms which accommodates 5 ms measurement time (PSS and SSS are transmitted once every 5 ms) and RF re-tuning time of 0.5 ms before and after the measurement gap. The measurement gap repeats with a periodicity of either 40 ms or 80 ms.

The eNB provides measurement gaps in the scheduling of the UE where no downlink or uplink scheduling occurs. Ultimately the network makes the decision,

UE will get the Measurement GAP configuration from RRC_Connection_Reconfiguration message while attaching to network and the Information Element(IE) is MeasGapConfig.

The MeasGapConfig consists of gap pattern type (gp0 or gp1) The gap patterns are to identify the periodicity and gapOffset

Each Measurement gap starts at an SFN and subframe meeting the following condition:

SFN mod T = FLOOR (gapOffset/10);

subframe = gapOffset mod 10;

with T = MGRP/10

where MGRP is 40 for gp0 and 80 for gp1

References:

1:

2:

1 Like
5

Ok.
We have gap 0 or gap 1 used for LTE inter /inter rat measurement, it’s known .
For gap0 we have offset value from 0 to 39.
How eNodeB decide this offset value to use?

6

Gap is decided based on cqi ri pmi priodicity.
Both should not collide.

7

Ok thanks!
So what about offset value linked with gap how it decide?
Like gap0 having offset 0 to 39.