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CC2745R10-Q1: The meaning of quality and confidence in channel sounding result?

James Austrial
Expert 3980 points
Part Number: CC2745R10-Q1

Tool/software:

Hi,

HW: Two TI CC2745R10 EVM and Two BP-EM-CS EVM
SW: SDK 9_11_00_18
APP: car node and key node

From car_node project (C: \ti\simplelink_lowpower_f3_sdk_9_11_00_18\examples\rtos\LP_EM_CC2745R10_Q1\ble\jar_node) , We can see range after the SDK calculates the distance, there are three values:
csResults-> distance , This is the range value
csResults-> quality , This is generated after this ranging
csResults-> confidence , Confidence is 100 for every reported distance

Take  one of the distance measurements in log for example:
[225-07-14 14 14:18:08, 941] root - DEBUG - NODE: 00:00:00: 00 NWP_CS_APP_DISTANCE_RESULTS --> {'type':'Event', 'command':'NWP','payload': {'event_type': 96, 'data': '2A:04:00:00:01:02:00:00:64:00:00'}
Data first 4 bytes is a distance, The value is 0x0000042A = 1066 (cm)
In the middle 4 bytes of data is quality and the value is 0x00000281 = 641 (score?)
Data last 4 bytes is confidence, now all 0x00000064 = 100, ignored in temporary

1.May I ask whether csResults-> quality can be a reference for range quality? A higher value means the more accurate of this range?

2.Will TI implement csResults-> confidence in the future?

3.What are the confidence and quality mean?

  • +1
    TI__Prodigy 140 points

    Hi,

    CS = Channel Sounding

    I recommend you to use the terminal information when you run the CS demo. The parameters are explicitly named, it's easier to understand the output. I highly recommend you to log the terminal print in a .txt file with a simple modification on the python script.

    1. The quality indicates how much deviation there is on the magnitude of the CS steps over the full CS subevents. Lower is the deviation, lower is csResults-> quality. So lower is csResults-> quality higher is the overall quality of the CS subevent. When csResults-> quality is low, most likely that the range quality is better.

    2. csResults-> confidence should be implemented in the future. However, I don't know when.

    3. The quality and confidence parameters are respectively the qualityPaths and confidencePaths value that corresponds to the "winning" path which is selected by Adaptive algorithm. Adaptive algorithm selects the best path of MUSIC or NN, based on the qualityPaths values. confidencePaths is not implemented at the moment. In the future it is espected to give a linear confidence metric on the distance estimation.

    Regards,

    Edgar Decreton