LTE Bandwidth

[Reeta Gaokar]

Is it possible to change lte module bandwidth other value than default. As per my understanding default value is 5Mhz (25 RB). If I want to increase it to 10 or 20 Mhz what changes need to do. I am not understanding why it is not accepting high bandwidth as the required database is already there in lte-amc.
Can anyone help me regarding this.
Thanks and Regards

[Nicola Baldo]

what did you try so far to do this?

[Reeta Gaokar]

Thanks for reply
I have change the bandwidth value in lte-enb-net-device and then i think it should reflect in scheduler part, as in scheduler considers rbgnum= dl_bw/rbg size. So as per the value of bw (25,50,100 etc), it will give rbg over which scheduling is done. This is my understanding.
Also i have one doubt regarding localized mapping approach which says that in a given subframe each RB is always allocated to the same user in both slots. That means there should be two RBs for UE in one TTI. In scheduler code only single RB is considered over a TTI (1ms), i think two RBs has to be consider as there are two slots in one subframe.
Please help regarding this
Thanks and Regards

[Marco Miozzo]

For what concern the configuration you may refer to the user documentation:
http://www.nsnam.org/docs/release/3.16/models/html/lte-user.html#configuration-of-lte-model-parameters

Regarding the RB issue, the scheduler work per RB basis since only one TB can be sent per RB basis (1 ms) from MAC perspective. From PHY level perspective there are 2 PRBs (physical resource block) of 0.5 ms each one, but they are used as a single RB from data point of view in the MAC level. More info:
http://www.nsnam.org/docs/release/3.16/models/html/lte-design.html#resource-allocation-model

Regards,
marco.

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[Reeta Gaokar]

I have changed dl bandwidth to 20 Mhz, only that change i have done in lte-enb-net-device
I am getting a error: terminate called after throwing an instance of 'std::out_of_range'  what():  vector::_M_range_check
Do i need to change any other parameter.

Regarding RB as you said on phy level there are two PRBs per TTI, so it means that the final received bytes/ throughput (for end to end system) per UE are over two PRBs.

Thanks and regards

[Marco Miozzo]

Hi.

for what concern the error you should post the code reproducing the error, otherwise is rather difficult to understand the origin of the error. In principle, the code works for the standard LTE bandwidths and the only parameter to be set is the LteEnbNetDevice.

Regarding the RBs, yes the final throughput reflects the transmission of data on the 2 PRBs.

Regards,

marco.

[Reeta Gaokar]

Ok i got what I am missing. I will try to rectify that error, it because of rbg size for which i need to do some modification in my code.

Thank you vary much Nicola and Macro for your help.

Regards