HSDPA 64 QAM usage

[cocoloco]

Hi experts,

I have 2 Nodes B with exactly the same configuration. In both its possible to achieve 21 Mbps but in one of them it never happens. Measurements have been done with excellent RF conditions, but in the 2nd Node B 64 QAM is never used. Could you give any idea???

Thanks

[rayhan]

Hi Dear,
Could you please tell me which device you are using for testing ,what is the DL category, is it CAT 14 or any other Rel 7 ..I hope you are using correct device.

[cocoloco]

Hi Dear,
Could you please tell me which device you are using for testing ,what is the DL category, is it CAT 14 or any other Rel 7 ..I hope you are using correct device.

Dear expert,

I use a CAT 14 device in both test. In one of them i achieve 21 Mbps and in the other one i only have 8-9 Mbps...

[wolverine]

I am assuming 64QAM is enabled on the second nodeB. Have you checked the transmission? Do you have the necessary E1's to carry 21Mbps?

[firstmaxim]

Perhaps, cell B has a different environment. Might be it is in an environment dominated by multipath, and cell A has a dominant LoS, the reason why 64 QAM was activated for this hspa+ cell.

Regards.

[firstmaxim]

Interesting point. Bottlenecks on the backhaul hinder the cell throughput significantly.

How about the scheduler? Are they having the same settings?

Regards

[onlygod]

What was your CQI during the test? 64QAM is very demanding and in practice, you need CQI higher than 25 to see any 64QAM usage and realistically you need at least CQI 27 to get a fair amount of 64QAM usage.

BTW, what was the 64 QAM Usage in percentage?

Also, don't think you'll get the max throughput under the site, sometimes it's better go about 300m away from the site and have a direct line of sight to it.

[cocoloco]

Hi all,

CQI was 27-28 during the test and we have 95-97 % usage of 64-QAM in cell A. I don´t have any information about E1 capability and the scheduler is supposed to be the same.