Hi Nordic Tech Support,
Our company is going to use Nordic nRF52832 on our next generation wireless product. I am the software engineer and doing the evaluation these days. Currently I am working on the throughput test. And I have one question to ask about:
By default, I am using the throughput example provided by your SDK nRF5_SDK_16.0.0. It is under the examples\ble_central_and_peripheral\experimental\ble_app_att_mtu_throughput.
The test result is OK and matches to the S132_SDS_v7.1_SoftDevice_Specification chapter 17. infocenter.nordicsemi.com/index.jsp
Then I want to do the similar test with NUS(Nordic UART Service) demo. I am using two Nordic nRF52832 EVK, one works as Master, the other as Slave. The initial code are using:
examples\ble_central\ble_app_uart_c (master) and examples\ble_peripheral\ble_app_uart(slave). I modified the code to make slave device send 1M bytes notification data to Master, just the same as the ble_app_att_mtu_throughput demo did. But when I use the NUS demo to test the throughput, no matter what parameters I changed (e.g. ATT MTU Size, Data length, Connection interval, etc.), My throughput results can not be improved as the ble_app_att_mtu_throughput demo did.
My test results with NUS are : Send 1M bytes notification data will cost almost about 2 min 10 seconds with LE 2M PHY(the same result with "Write Command") , so the throughput is about 8kB/s = 64 kbps. It is not possible to achieve the typical case in ble_app_att_mtu_throughput demo 256 kbps (ATT MTU = 23, event length = 7.5ms, connection interval = 7.5ms), it is even not possible to achieve much higher throughput of 1327 kbps (ATT MTU = 247, data length = 251, event length = 50 ms, connection interval = 50m).
Comparing to ble_app_att_mtu_throughput demo , I don't know why the throughput results between two EVKs over NUS would decrease so much, . I searched in the DevZone ,but did not find the clear answer. Some posts said that with NUS service, the throughput can not go over 10kB/s= 80 kps, Is that right? If not, what should I change in the examples\ble_central\ble_app_uart_c or examples\ble_peripheral\ble_app_uart to improve the throughput to make it match the results tested on examples\ble_central_and_peripheral\experimental\ble_app_att_mtu_throughput.
Thanks, hope to get your feedback.
