nRF9160 DK maximum throughput

RE: nRF9160 DK maximum throughput

Didrik Rokhaug — Tue, 27 Jul 2021 15:31:36 GMT

This and this link gives a good explanation of the iperf output.

Normally, the client is the one to send data. This means that normally, you only measure upload datarate. With the -R flag, you reverse the roles of the server and client, so that it is the server that sends data, and the client that receives it. So without the -R flag, you get upload, while with the -R flag you get download. The sender and receiver datarates gives you the datarate meassured by the sender (client without -R, server with) and the receiver (server without -R, client with).

RE: nRF9160 DK maximum throughput

Frikkie Badenhorst — Tue, 27 Jul 2021 08:44:51 GMT

Thanks Didrik. I also just want to make sure we are interpreting this correctly. For your above command (downloading TCP payload), we get a result of:

Test Complete. Summary Results:
[ ID] Interval Transfer Bitrate Retr
[ 5] 0.00-30.01 sec 681 KBytes 186 Kbits/sec 0 sender
[ 5] 0.00-30.01 sec 618 KBytes 169 Kbits/sec receiver

What is the differences between the sender and receiver bitrates? Is sender the UL bitrate and receiver the DL bitrate? If so, why then if we remove the "-R" argument (upload TCP payload) from the command we get a much larger bitrate of about 300kbps?

It does indeed look like increasing the payload decreases the throughput, thanks

RE: nRF9160 DK maximum throughput

Didrik Rokhaug — Tue, 27 Jul 2021 08:24:10 GMT

I simply used the command from the documentation:

iperf3 --client ping.online.net --port 5202 -l 3540 --time 30 -V -R

Using a smaller buffer size (like you did), would probably increase the throughput as it reduces the need for fragmentation.

RE: nRF9160 DK maximum throughput

Frikkie Badenhorst — Tue, 27 Jul 2021 07:10:26 GMT

Thanks for the information, Didrik.

We have been able to start testing on a local public network in the UK and were thus able to use the iperf command to test throughput (TCP).

We use the following command for UL test (on a public iperf3 server):

- iperf3 -c speedtest.serverius.net -p 5002 -l 705 -t 30

We the obtain an UL bitrate of 319kbps:

-[ ID] Interval Transfer Bitrate
[ 5] 0.00-30.00 sec 1.14 MBytes 319 Kbits/sec sender
[ 5] 0.00-30.00 sec 1.14 MBytes 319 Kbits/sec receiver

Then for the DL test:

- iperf3 -c speedtest.serverius.net -p 5002 -l 705 -t 30 -R

We then obtain a DL bitrate of about 200kbps:

[ ID] Interval Transfer Bitrate Retr
[ 5] 0.00-30.00 sec 750 KBytes 205 Kbits/sec 0 sender
[ 5] 0.00-30.00 sec 698 KBytes 191 Kbits/sec receiver

Could you confirm that we are using the same commands as you for this TCP throughput test? The values we are seeing is somewhat larger than the values you are seeing, and I thus assume that the differences in our and your values are only caused by the different local networks and eNBs we are using (we should see the same UL/DL values when our UE is placed next to yours on the same network).

RE: nRF9160 DK maximum throughput

Didrik Rokhaug — Thu, 22 Jul 2021 10:09:49 GMT

I am not aware of any methods for improving the throughput on the LTE level.

However, it is possible to improve the IP throughput by tweaking the size of the shared buffers between the application and modem cores: https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrf/include/modem/nrf_modem_lib.html#partition-manager-integration

RE: nRF9160 DK maximum throughput

Frikkie Badenhorst — Wed, 21 Jul 2021 14:04:31 GMT

Thanks,

We have support on the callbox and can thus investigate that further ourselves.

However I am also trying to understand whether there any are settings on the nRF9160 application level that can influence the throughput? If not, I would expect that the mosh.hex modem shell which you sent will give the same throughput as the application that we currently have installed? In this case it also sounds like the throughput is determine only by the eNB?

RE: nRF9160 DK maximum throughput

Didrik Rokhaug — Wed, 21 Jul 2021 13:15:33 GMT

It is done on the eNB side.

However, I don't have much experience with callboxes myself, so I can't really help you more than that.

RE: nRF9160 DK maximum throughput

Frikkie Badenhorst — Wed, 21 Jul 2021 12:56:10 GMT

Hi Didrik,

Thanks for the precompiled version - will test it as soon as possible. Will also confirm that the tested eNB can handle this values.

In the meantime, could you please elaborate more on how to increase the PRB and MSC? Is this done on the UE side or eNB side?

RE: nRF9160 DK maximum throughput

Didrik Rokhaug — Wed, 21 Jul 2021 12:38:34 GMT

Hi,

First, it is worth noting that those numbers are peak throughput for the physical layers, so you will most likely not see those numbers from the application.

You should also note that it will depend on the tested/eNB if those numbers can be acheived.

That said, those numbers sounds very low. When I use the iperf command in the newly added modem shell sample, I got averages of ~ 120 kbps UL and ~ 100 kbps downlink on the local network.

To increase the speed, you can try to increase the PRB and MSC.

I've also attached a precompiled version of the modem shell if you want to try that. You can find the documentation here: modem shell.

devzone.nordicsemi.com/.../mosh.hex

Best regards,

Didrik