nrf52833 BLE Packet Loss Rate High

RE: nrf52833 BLE Packet Loss Rate High

Vidar Berg — Tue, 16 Jul 2024 12:12:45 GMT

Hi Soloman,

Please check the debug log to see what error led to the reset.

Best regards,

Vidar

RE: nrf52833 BLE Packet Loss Rate High

soloman — Tue, 16 Jul 2024 12:11:04 GMT

Hi Vidar,

I try to set que_size，but the board still reset when the value is not 1. It will run for a while and then reset, when the value is 1.

Thanks,

Soloman

RE: nrf52833 BLE Packet Loss Rate High

Vidar Berg — Tue, 16 Jul 2024 11:18:36 GMT

Hi Soloman,

Thanks for confirming. So, this problem can be mitigated by increasing the notification queue size as discussed in this thread: Increase hvn_tx_queue_size to maximize throughput

Best regards,

Vidar

RE: nrf52833 BLE Packet Loss Rate High

soloman — Tue, 16 Jul 2024 11:15:11 GMT

Hi Vidar,

Yes!Yes! The return code is 0x13, that means NRF_ERROR_RESOURCES.

Thanks,

Soloman

RE: nrf52833 BLE Packet Loss Rate High

Vidar Berg — Tue, 16 Jul 2024 11:09:32 GMT

Hi Soloman,

In that case, please double check that you are reading the return code correctly. The log message will print the hexadecimal value while the error codes are listed with their decimal values. Error 0x13 is the same as NRF_ERROR_RESOURCES ('19').

RE: nrf52833 BLE Packet Loss Rate High

soloman — Tue, 16 Jul 2024 10:54:56 GMT

Hi Vidar,

There didn't trigger the BLE_GATTC_EVT_TIMEOUT or BLE_GATTS_EVT_TIMEOUT event in ble_evt_handler, when setting breakpoints to this two position. And this problem was seen with different central.

Thanks,

Soloman

RE: nrf52833 BLE Packet Loss Rate High

Vidar Berg — Tue, 16 Jul 2024 10:11:11 GMT

Hi Soloman,

It's an easy mistake to make. However, the NRF_ERROR_TIMEOUT (13) error is an uncommon for the HVX call. It indicates that there has been a GATT procedure timeout in the current connection. This should also trigger either the BLE_GATTC_EVT_TIMEOUT or BLE_GATTS_EVT_TIMEOUT event. Can you please check which of these two events were triggered? Also, do you see the same errors with different central devices?

Best regards,

Vidar

RE: nrf52833 BLE Packet Loss Rate High

soloman — Tue, 16 Jul 2024 09:58:36 GMT

Hi Vidar,

I'm very awkward for this mistake. I do test again and the return value is NRF_ERROR_TIMEOUT. Why does packet sending time out when the interval is 10ms, but when the interval is larger, such as 50ms, it does not time out?

Thanks,

Soloman

RE: nrf52833 BLE Packet Loss Rate High

Vidar Berg — Tue, 16 Jul 2024 09:34:42 GMT

Hi Soloman,

Thanks for sharing the code. The if statement in the code snippet below will never evaluate to true.

    err_code = sd_ble_gatts_hvx(ulConnHandle, &hvx_params);
    if ((err_code == NRF_SUCCESS) && (hvx_len != usLen))
    {
        NRF_LOG_DEBUG("Failed sending notification. Error 0x%x. ", err_code);
    }

So you will not get any error message if the sd_ble_gatts_hvx() function, for instance, returns with NRF_ERROR_RESOURCES.

Please try this instead:

    err_code = sd_ble_gatts_hvx(ulConnHandle, &hvx_params);
    if (err_code != NRF_SUCCESS)
    {
        NRF_LOG_DEBUG("Failed sending notification. Error 0x%x. ", err_code);
    }

Best regards,

Vidar

RE: nrf52833 BLE Packet Loss Rate High

soloman — Mon, 15 Jul 2024 11:47:08 GMT

Hi,

I found there is no packet lost, when the packet is shorter than 100 bytes. But the MTU is set to 251 successfully, and exchanged mtu with the centeral is successful.

Thansk,

Soloman

RE: nrf52833 BLE Packet Loss Rate High

soloman — Sat, 13 Jul 2024 07:34:12 GMT

Hi Vidar,

This is my mini keil5 project, which the steps of testing as follow:

step 1. compile the project and download to board.

step 2. connect with debug application on mobile phone in 15s.

step 3.After the board is powered on or reset for 15s, timer2 will send 20 packets(1 packet per 10 ms) to the application after power on by characteristic2.

You can observe the statistics of the application, where the first four bytes of the message are the frame number. In addition, the device name is Nordic_UART.

Thanks,

Soloman.

devzone.nordicsemi.com/.../nrf52833dk.rar

RE: nrf52833 BLE Packet Loss Rate High

Vidar Berg — Fri, 12 Jul 2024 14:23:35 GMT

Hi Soloman,

The fact that you experience the same issue with your phone helps narrow down the problem. I suspect the issue may be with the data or error handling in your application. I can try reproducing this on my end if you are able to share a minimal version project here.

Best regards,

Vidar

RE: nrf52833 BLE Packet Loss Rate High

soloman — Fri, 12 Jul 2024 13:00:45 GMT

Hi Vidar,

I did a test with mobile phone Bluetooth debugging app as centeral just now, and the result shows debugging app didn't receive enough packets，that the loss rate is 9/20.

Best regards,

Soloman

RE: nrf52833 BLE Packet Loss Rate High

Vidar Berg — Thu, 11 Jul 2024 11:55:03 GMT

Hi Soloman,

Data transmission in the Bluetooth protocol is reliable by design. Therefore, as long as the packet is successfully added to the transmission queue (i.e., when sd_ble_gatts_hvx() returns with SUCCESS), the packet should be received by the gatt client.

[quote user="soloman"]and there is no proper tool to capture the packet to determine whether it was sent from slave.[/quote]

You can capture the on-air traffic with a Bluetooth sniffer such as this one: https://www.nordicsemi.com/Products/Development-tools/nRF-Sniffer-for-Bluetooth-LE

Have you tried testing this with other centrals, such as an Android or iOS device, to see if you experience the same issue? You can use our nRF connect app to test reception.

Best regards,

Vidar

RE: nrf52833 BLE Packet Loss Rate High

soloman — Thu, 11 Jul 2024 08:55:50 GMT

Hello,

Yes, the return code of sd_ble_gatts_hvx is still SUCCESS when slave nrf52833 transmits packet per millisecond, while the master is a bluetooth module. I find master not receive packet enough, and there is no proper tool to capture the packet to determine whether it was sent from slave. So, you said nrf52833's BLE is reliable, that means slave nrf52833 transmits packet per millisecond is reliable, right? In addition, what configuration may occur the slave machine fails to send even if the packet sending function returns success, when the SDK is nRF5_SDK_17.1.0_ddde560.

Thanks,

Soloman

RE: nrf52833 BLE Packet Loss Rate High

Vidar Berg — Thu, 04 Jul 2024 11:34:30 GMT

Hello,

Data transmission in BLE is reliable. That is, if the packets fails to be sent after x retransmits (number of retransmit attempts are determined by the connection parameters), the connection will be terminated by the BT stack. So, I'm wondering where you are seeing the packet loss? Do you check the return code from the notification send function? Also, which SDK are you working with?

Thanks,

Vidar