top button
Flag Notify
    Connect to us
      Site Registration

Site Registration

How CQI 15 & MCS 28 will map in LTE?

+1 vote
531 views

How CQI 15 & MCS 28 will map in LTE?

posted Jul 27, 2018 by Mohit Mohan

Share this question
Facebook Share Button Twitter Share Button LinkedIn Share Button

1 Answer

0 votes

Hi Mohan,

Single CQI value can be mapped to multiple MCS value, say CQI 15 can be mapped to MCS 23 to 28. If UE reports CQI value 15 then it is ENB implementation which MCS to select among 23 to 28 (It is just an example). Why this variation is each MCS is having an different coding rate and efficiency of utilization. If you select 28 as MCS then efficiency is more but there can be chance of loss of more coding rate. If you slect 23 as MCS then throughput will be less because of less coding rate and efficiency .

it is ENB implementation how to handle the UE in relatime .

answer Aug 3, 2018 by Jaganathan
Thanks for your answer. I want to know how to implement it in Enb side & how code rate & TBS size calculated.
Similar Questions
+3 votes

EnodeB considers CQI feedback from the UE before creating the transport block.
As per my understanding PUCCH resource allocation is not very dynamic. In this case how UE decide to use a specific MCS (Modulation and Coding Scheme) while using PUCCH channel ?

0 votes

Many values for the MCS index have been defined in the specification. Value ranges from 0 to 31.
Each MCS index values corresponds to different combination of "number of spatial streams + modulation type + Coding rate" .
In case of PDSCH resource allocation, eNodeB considers feedback from the UE but in case of PMCH where data is transmitted only at downlink. How a particular MCS index would be chosen for multimedia multicast broadcast data transmission ?
If I am correct, selection of MCS index is done at MCE and sends to eNodeBs/cells belong to the same MBSFN area ?
In this case when MCS index is selected by MCE, how MCE take decision on this factor ?
I am also looking for set of MCS index values which can be used for MBMS transmission ?

0 votes

UE can send SR at any time and CQI at configured time, for these two request how many RB's are allocated from ENB?

+1 vote

Since eNodeB can have information about channel quality with finer granularity through selected
subband CQI, wouldn’t it make sense to have MCSs defined on a per‐RB (or a group of RB) basis rather
than a single MCS per UE across all allocated RBs for a codeword?

...