No change in CQI even after channel switch

[Anand B]

Hi All,

I am considering a scenario where there are 2 eNBs on a x-axis line, some region overlapping with each other. Initially both eNB's are operated on the same channel. My custom script is run for 2 seconds on this channel for eNB0 and switched to some other non-overlapping channel for the rest of the simulation time. I am collecting CQI values of eNB0 for the entire simulation time. Even though I switch the downlink operating Channel of eNB0, the CQI values doesn't seem to change. I have gone through earlier posts on constant CQI reporting problems, but the solution provided there was to use a fading model. I do not want to consider a fading model in my script and rather observe CQI changes purely based on  interference because of the channel switch. Any help in solving this issue is appreciated. Thanks in advance.



Thanks,
Anand   

[hongyu deng]

Hi Anand,

Do you know which channel the ENB or UE used in the process of the simulator?(Can you output which channel was used in terminal?)  Or which code shows the relevant info, do you know that?

As you said,the CQI of the sub-channel does not change in simulator process(All are 15), and i don't know why too.

Havefun,

Hongyu.

[Anand B]

On Monday, March 21, 2016 at 7:03:34 PM UTC+5:30, hongyu deng wrote:

Hi Hongyu,

Do you know which channel the ENB or UE used in the process of the simulator?(Can you output which channel was used in terminal?)  Or which code shows the relevant info, do you know that?

-->  Yes I know(I can output which channel was used in terminal). you can get that using GetDLEarfcn(),GetULEarfcn() for downlink and uplink, respectively.

 

As you said,the CQI of the sub-channel does not change in simulator process(All are 15), and i don't know why too.

 

--> I am getting different CQI for different UE that is not my problem.

My problem is, initially both eNBs are using same channel then because of interference I am expecting less CQI to users but after changing channel of one eNB I am expecting better CQI because of no interference. But I am getting same CQI in both the cases for each User.

 

Thanks,

     Anand

[hongyu deng]

Hi Anand,

 

YES,i can output like this:ulBandwidth:25 dlBandwidth:25 ulEarfcn:18100 dlEarfcn:100 cellId:1.

As is shown,we know that the UL frequency is 18100kHz,and DL frequency is 100kHz,is it right?

My question is can i know which sub-channel was used in data transmits,e.g.There are 25 sub-channels in LENA system,0-24,can i get which one was used in Tx/Rx?

To your question,I think the interference here is no the important thing,you can read The LENA ns-3 LTE Module Documentation.pdf for some help.

And do you know how to change the frequency(channel) in the process of the simulator?

BRs

Hongyu.

[hongyu deng]

Hi Anand,
 I'm sorry for my answer,it is incorrect.

YES,i can output like this:ulBandwidth:25 dlBandwidth:25 ulEarfcn:18100 dlEarfcn:100 cellId:1.

As is shown,we know that the UL frequency is 18100kHz,and DL frequency is 100kHz,is it right?

The ulEarfcn 18100 corresponding the  physical frequecy is 2120MHz,and dlEarfcn:100 corresponding the  physical frequecy is 1930MHz.

BRs

Hongyu.