number of UEs ?

[senthil kumar]

Hai,

I have one problem regarding number of UEs in LTE

i am using ns-3.21

when i increase number of UEs to 40  ,  it gets error like this

msg="too many UEs (41) for current SRS periodicity 40, consider increasing the value of ns3::LteEnbRrc::SrsPeriodicity", file=../src/lte/model/lte-enb-rrc.cc, line=2360

terminate called without an active exception..

and i go through that regarding file lte-enb-rrc.cc 

but i can not understand ?  how could i increase number of UEs to my scripts?

// from 3GPP TS 36.213 table 8.2-1 UE Specific SRS Periodicity

static const uint8_t SRS_ENTRIES = 9;

static const uint16_t g_srsPeriodicity[SRS_ENTRIES] = {0, 2, 5, 10, 20, 40,  80, 160, 320};

static const uint16_t g_srsCiLow[SRS_ENTRIES] =       {0, 0, 2,  7, 17, 37,  77, 157, 317};

static const uint16_t g_srsCiHigh[SRS_ENTRIES] =      {0, 1, 6, 16, 36, 76, 156, 316, 636};

 from the above values i used 20 UEs and its works fine.. when i increase 40 UEs i got error..

how can i use these values?

anyone help me?

[Tommaso Pecorella]

Hi,

according to the forums, you're using ns-3 for quite a bit now. As a consequence, you should know what's an Attribute when you find one.

Moreover, the error message is really explicative. I couldn't figure out how to make it clearer.

It clearly states to change the "ns3::LteEnbRrc::SrsPeriodicity" element. 

Check the LteEnbRrc class documentation:

https://www.nsnam.org/docs/doxygen/classns3_1_1_lte_enb_rrc.html#a28603f43a736c5d9fab4831670fd4c7a

there is a "SrsPeriodicity" attribute.

Moreover, a simple "grep" search would had pointed directly to the answer.

T.

[senthil kumar]

Hai dear,

Thanks for your reply.. I have studied that one .. but i could not understand why i am getting error ?

[Konstantinos]

Because, as the error suggested, SRS periodicity is not enough and you need to increase it. 

If you do not know why it needs to be increased, then you need to study how LTE works. This is not a NS-3 issue.

e.g. some links from google search.

http://www.sharetechnote.com/html/Handbook_LTE_SRS.html

http://howltestuffworks.blogspot.co.uk/2014/07/sounding-reference-signal-procedure.html

[senthil kumar]

Thanks again.. I got it.. its really good documentation.. 

[qq550...@gmail.com]

I am sorry to bother you after so long . i am facing the same problem. Could you help me with it? 

在 2015年3月9日星期一 UTC+8下午5:14:07，senthil kumar写道：

[Tommaso Pecorella]

I'm sorry, but it's against my religion to answer to anyone writing in a thread something like "I got the same problem" or similar.

To be honest I should hit you with stones until you beg for forgiveness (so it is written in The Book), but it's also written that we don't have to chase around the globe the sinners.

Have fun,

T.

[layonth]

why do you want to hit me? But I will never beg for mercy.........

在 2015年11月2日星期一 UTC+8下午10:09:04，Tommaso Pecorella写道：

[Tommaso Pecorella]

Well, as a start this thread was closed with a quite explicit description of the problem and of the solution.

Secondly, the original thread was referring to ns-3.21. We're now at 3.24.1, so you do not have exactly the same problem (similar maybe, but not the same).

Third, because we already discussed what is the solution (see point 1), so...

Summarizing: what part of the thread is obscure to you ? Have you followed the thread advices about increasing the SrsPeriodicity ? Do you know how to modify an Attribute ? 

T.

[layonth]

Thanks for your kind reply to a sinner. well, why not the same? I can use the same code, the outcome is certainly the same. Also I have no idea about what they say above. But your last sentence figured out what I should do. Lastly,"The same..." go against your religion? why? now that the word are made, why not the same.......

L   

在 2015年11月3日星期二 UTC+8下午10:02:11，Tommaso Pecorella写道：

[Tommaso Pecorella]

Hi,

you're right, but I'd assume that the code will be not identical. Moreover, I assume that you *did* apply the suggested steps, which seems that was a bad assumption.

I'd suggest to read the tutorial and manual if the suggested (at the time) solution is unclear.

If there's something obscure in the tutorial or manual (it can happen), you can and should open a different thread - unless that has been discussed as well. E.g., "what is exactly an Attribute and how these are different from instance variables" could be a valid question.

Indeed, the first thing is to understand what has been written in this post before, because even if you have the same (or similar enough) issue, the answer will be the same, and if you didn't understand the previous one, you'll not understand the new one either. Logical...

Cheers,

T.