NUS bluetooth data rate

Dear Teao of Nordic,

which is Bluetooth data rate of NUS example ind case 1 and case 2? Is it dependant of Softdevice Version? Can data rate be configured?

Is it 1Mbit per Default? which means Bluetooth 4.x?

case 1:

using nRF5_SDK_12.3.0_d7731ad


case 2:

using nRF5_SDK_15.0.0_a53641a


thank you....

  • The data rate of BLE on the physical and link layer layer is determined by:

    1. The symbol rate/bit rate (1000, 2000, 125, and 500kbps)
    2. Connection interval
    3. Number of packets per connection interval (connection event length extension)
    4. Packet lengths
    5. Packet error rate (link quality)

    The data rate of two devices communication over BLE is determined by:

    1. The capabilities of the BLE radio on both sides of the link
    2. The capabilities of the BLE controller and host on both sides of the link
    3. Link roles, the Central determines the connection parameters (GAP layer), a Peripheral can only request a given set of parameters.
    4. The applications running on the devices. 

    What this means for our NUS example is that the data rate is dependent on the capabilities of the devices on both sides of the link. This is most notable when in a connection with a smartphone as Android and iOS have to leverage the on-air time of its BLE radio with BT classic and most importantly its WIFI activity. There are many manufacturers with many different radios running many different BLE controllers with different wifi modems and ultimately different OS'es. 

    To answer your question; 1000kbps is the default BLE symbol rate and you can change all the parameters mentioned above. The problem is that the data rate as seen by the application is not very deterministic and you will have to conduct measurements for your specific use case. 

    I strongly urge you to use S132 V6.0 (soon 6.1) and SDK15 as it has more capabilities and is more mature than V3.1

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