Why changing the LTE system bandwidth has no effect on the user TCP throughput?

[hy zhao]

I want to observe  the impact of LTE system bandwidth on TCP throughput,  

Use the following code：

 lteHelper->SetEnbDeviceAttribute ("DlBandwidth", UintegerValue (6));

 lteHelper->SetEnbDeviceAttribute ("UlBandwidth", UintegerValue (6));

But, When I change the bandwidth, there is no change on the tcp throughput. I don't konw why,  If you have any suggestions,please tell me .

Thank you.

[Mahmud Islam]

Hi,

Have you checked MCS number and Transport Block Size? 

It should change with the numbers of resource block.

Thanks

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[hy zhao]

Hi ,thank you for your suggestion.

but, What does the Transport Block Size refer to? How to change the MCS and Transport Block Size? 

I didn't notice these two parameters before.  Could you please give me some code ?

Thank you very much.

在 2017年10月31日星期二 UTC+8下午4:22:38，Mahmud Islam写道：

Hi,

Have you checked MCS number and Transport Block Size? 

It should change with the numbers of resource block.

Thanks

On Mon, Oct 30, 2017 at 10:18 PM, hy zhao <zhy...@gmail.com> wrote:

I want to observe  the impact of LTE system bandwidth on TCP throughput,  

Use the following code：

 lteHelper->SetEnbDeviceAttribute ("DlBandwidth", UintegerValue (6));

 lteHelper->SetEnbDeviceAttribute ("UlBandwidth", UintegerValue (6));

But, When I change the bandwidth, there is no change on the tcp throughput. I don't konw why,  If you have any suggestions,please tell me .

Thank you.

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[Mahmud Islam]

When you will run LTE script you will get some output trace file where you can get transport block size and MCS number and so on.Please read the tutorial. Based on that you can also calculate MAC layer throughput. 

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[hy zhao]

Hi sir,

I have checked the MCS number and Transport  Block Size,  I found that the two parameters did not change and were always the maximum. 

Is this a normal phenomenon? I think there's a problem.

Could you please give me some suggestions?

Thank you very much !

在 2017年10月31日星期二 UTC+8下午4:22:38，Mahmud Islam写道：

Hi,

Have you checked MCS number and Transport Block Size? 

It should change with the numbers of resource block.

Thanks

On Mon, Oct 30, 2017 at 10:18 PM, hy zhao <zhy...@gmail.com> wrote:

I want to observe  the impact of LTE system bandwidth on TCP throughput,  

Use the following code：

 lteHelper->SetEnbDeviceAttribute ("DlBandwidth", UintegerValue (6));

 lteHelper->SetEnbDeviceAttribute ("UlBandwidth", UintegerValue (6));

But, When I change the bandwidth, there is no change on the tcp throughput. I don't konw why,  If you have any suggestions,please tell me .

Thank you.

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[Mahmud Islam]

Try to change different distances between enB and UE. When you will increase distance SINR will fall and MCS number will be changed and trasport block size will also be different.

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[hy zhao]

Thank you sir,

Your proposal is very reasonable, changing the distance does affect the throughput, but my question is, 

does not affect the throughput of the system bandwidth, I think that reduce the system bandwidth, 

the throughput will be reduced, but now the situation is changing the bandwidth of the system had no effect on the throughput, 

I don't understand why is this phenomenon.

Thank you for your patient. you are so kind.

在 2017年10月31日星期二 UTC+8下午5:18:37，Mahmud Islam写道：

[Mahmud Islam]

In LTE there is Adaptive Modulation and Coding scheme that means it is very advanced technology. Throughput definitely depends on system bandwidth but if SINR is too high then throughput for certain system bandwidth will remain same for a particular scenario. Now, let's say you have changed distance and you get some change throughput now at that particular distance increase the system bandwidth definitely you will get more throughput.

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[hy zhao]

Hi sir,

Thank you very much for your advice. I'll try it right away.

在 2017年10月31日星期二 UTC+8下午5:34:36，Mahmud Islam写道：

[jackey chen]

do you solve this problem?I met the same question ...

在 2017年10月31日星期二 UTC+8下午4:18:16，hy zhao写道：

[jackey chen]

do you solve this problem?I met the same question ...

在 2017年10月31日星期二 UTC+8下午4:18:16，hy zhao写道：

I want to observe  the impact of LTE system bandwidth on TCP throughput,