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Channel Quality Indicator (CQI) reporting period and Downlink (DL) throughput

+3 votes

How the CQI reporting period and the DL throughput are related?

The lower CQI reporting period, the better link adaptation, so better Modulation and Coding Scheme (MCS) assignment and higher throughput?

If this is true, the best option should be to set CQI-PMI-ConfigIndex to lower values, am I right?

CQI-PMI = Channel Quality Indicator - PreCoding-matrix-Indicator.

posted Mar 26, 2014 by Samardeep Acharya

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1 Answer

+3 votes

Partially yes, if you have short reporting period, the link adaptation can adapt faster. However practically for very fast changing conditions, the “transmission -> feedback -> next transmission” loop may be too slow and it’s better to average the feedback and use lower order MCS.

The second thing is, that if there’s an application which requires relatively low throughput to fulfill QoS requirements, using fast adaptation rate (and thus low periodicity for feedback) will require high throughput for the feedback itself, and thus is not very efficient, in that case sometimes it’s also better e.g. to use larger period for feedback to have relatively good overhead/throughput ratio.

answer Mar 28, 2014 by Hiteshwar Thakur
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+1 vote

I don't know the complete use of CQI at eNodeB. Does it impact only downlink scheduling parameters or also considered while granting uplink resources ?

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