RE: NUS bluetooth data rate

haakonsh — Thu, 12 Jul 2018 10:31:01 GMT

see Central PHY Update and Peripheral PHY Update. I suggest you search DevZone for similar questions because it has been answered before.

In general you'll find what you need by looking through the S132 SoftDevice v6.0.0 API documentation and SDK API Reference documentation.

We're a bit short staffed during the summer vacation, so you'll have to do some research on your own.

RE: NUS bluetooth data rate

Tom80 — Thu, 12 Jul 2018 09:22:15 GMT

Dear haakonsch,

thank you for this Information.

Just for Information only....

how could Symbol data rate be changed to 2000kbps? Would this be possible?

RE: NUS bluetooth data rate

haakonsh — Thu, 12 Jul 2018 08:59:53 GMT

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

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

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

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