What will be the effect if Operator changes the Default Bearer Quality Channel Indicator from QCI-9 to QCI-8?

Question

As i know two type of CQI in lte, sub band CQI and wide band CQI. I wide band CQI it sends channel quality for whole bandwidth but in case of sub band CQI how UE calculates CQI?

Answer 1

Operator normally use both QCI-8 and QCI-9 for data services, the only difference is that QCI-9 is used for normal subscribers where QCI-8 for premium subscribers. QCI-8 Priority might be slightly greater than QCI-9. It depends upon the implementation occur in the network. Both QCI-8 and QCI-9 have same PDB and PELR from 3GPP. There would not be any difference if whole network is implemented on one QCI either QCI-8 or QCI-9. It may not be critical for you if there is no subscriber differentiation in your network.

It will be entertained only when the implementation has been deployed with mix up of both QCI's. In that case QCI-8 will be considered slightly higher priority on air as compared to QCI-9. Another thing would be to check the IP Differentiation Service Code Point (DSCP) marking of QCI8. This is important to align particularly when your back-haul is shared amongst various services.

At bottom line there would not be much effect if Operator changes the whole network QCI from 9 to 8.

Answer 2

LTE has defined 1 to 9 QCI (Qos Class Identifier) values. Each one has its associated packet delay and packet loss. As far as I know, both (8 and 9) both QCI values correspond to Non-GBR bearer as well as same packed delay tolerance (300 ms) and packet loss i.e 1 out of ten lakhs packet (10 to the power -6).

Waiting for others to respond.

Answer 3

You can set QCI9 to be a higher priority as you can use QCI priority weights in your network but operators usually left QCI9 for low priority devices. Some operators keep both QCI8 and QCI9 defining them for different user profiles ( for instance QCI8 for mobile and QCI9 for fixed users FMS ( Fix to mobile substitution) with same CQI scheduling weight in order to separate counters and KPIs and being able to monitor easier both groups of users separately.