Sending large file with BLE notifications: throughput seems limited

RE: Sending large file with BLE notifications: throughput seems limited

Kenneth — Tue, 16 Aug 2022 12:40:08 GMT

If you compile in SES you should for instance see something like:

then, it depends on whether you also have a bootloader at the end of flash how much flash will be availble for FDS.

Typically the *.map file in your build output should give information about RAM and code usage, look for 'Image component sizes' for instance if compiled with Keil.

Kenneth

RE: Sending large file with BLE notifications: throughput seems limited

JuanHG — Thu, 11 Aug 2022 06:49:51 GMT

Hi Kenneth,

Do you have an idea of how I may solve the described issue ?

Thanks in advance

RE: Sending large file with BLE notifications: throughput seems limited

JuanHG — Tue, 26 Jul 2022 10:11:51 GMT

Hi Kenneth,

Thanks a lot for your answer !

I have succeeded in using the BLE sniffer and thus saw that notification payloads are indeed split into multiple PHY packets.

I was able to switch to S113 but unfortunately this leads to the following runtime error because of lack of flash:

<error> peer_manager_pds: Could not initialize flash storage. fds_init() returned 0x860A.
<error> peer_manager: pm_init failed because pds_init() returned NRF_ERROR_STORAGE_FULL.
<error> app: Fatal error
<warning> app: System reset

How can I know how much data I need to save in my code to make the peer manager have enough memory available ?

Thanks in advance

Best regards

RE: Sending large file with BLE notifications: throughput seems limited

Kenneth — Mon, 25 Jul 2022 11:28:51 GMT

Hello,

An on-air sniffer log, e.g. using nRF sniffer for BLE could be helpful to understand what may be limiting the throughput in specific.

There is a nice blogpost here that describe how to improve throughput:
https://novelbits.io/bluetooth-5-speed-maximum-throughput/

Have in mind that S112 does not support Data Length Extension (DLE), which means the maximum packet that can be sent on-air is only 23bytes (so the ~500byte MTU will be split into several 23byte on-air packets), this will decrease the throughput a lot. I recommend to consider the S113 that support up to 244bytes of data in each packet.

Best regards,
Kenneth