CQI calculation by UE?

[lteman]

I would like to know if CQI calculated by UEs are instantaneous values or does UE perform some averaging before sending it to the network? Any ideas from UE experts are welcome...

[giegala]

It is up to UE/Chipset manufacture. In practice it should be instantaneous, as in most networks it is being reported every 2ms

[maya]

Hi Experts,

Can Anyone share any document regarding CQI Calculation on UE side, in LTE??

[xcatas]

Hi,

That's the same question that I asked to internet around two years ago.. (while doing final research about HSPA for my bachelor degree)
I found a paper from internet that already doing lab measurements for this SINR to CQI mapping (HSPA). They make this formula :

CQI = 0 ; for SINR <= -3.5 dB
CQI = SIR + 3.5dB ; for SINR between -3.5 to 26.5 dB
CQI = 30 ; for SINR >= 26.5 dB

I could upload paper containing that formula if you like. maybe tomorrow, I didn't bring my backup harddisk now.

That's for HSPA. For LTE, idk yet...

[FrankPintor]

It is up to UE/Chipset manufacture. In practice it should be instantaneous, as in most networks it is being reported every 2ms

One of the common optimizations to reduce RTWP is to increase the CQI reporting period to 8ms.

[kevinwjs]

In LTE, adaptive MCS has to ensure a BLER value smaller than 10%. The SNR-CQI mapping function can be obtained by intensive simulation. Paper attached.

phylayer_simu.7z

[rabatcasa]

Hi,
In LTE, the Ue should not apply any filtering for the CQI, Please refer to LTE 3GPP spec 36.213 Chapter.
3GPP states : - In the time domain, the CQI reference resource is defined by a single downlink subframe n-n_{CQI_ref},-

BR/Casa