TIDUFD0 August   2025

 

  1.   1
  2.   Description
  3.   Resources
  4.   Features
  5.   Applications
  6.   6
  7. 1System Description
  8. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 Design Considerations
      1. 2.2.1 Wireless Hardware Configurations
      2. 2.2.2 Auxiliary Power Strategy
      3. 2.2.3 Thermistor Multiplexer
      4. 2.2.4 Cell Balancing
    3. 2.3 Highlighted Products
      1. 2.3.1 CC2662R-Q1
      2. 2.3.2 BQ78706
      3. 2.3.3 TMUX1308
      4. 2.3.4 LM5168
      5. 2.3.5 TMP61
  9. 3Hardware, Software, Testing Requirements, and Test Results
    1. 3.1 Hardware Requirements
    2. 3.2 Software Requirements
    3. 3.3 Test Setup
    4. 3.4 Test Results
      1. 3.4.1 Network Performance
        1. 3.4.1.1 Network Initiation
        2. 3.4.1.2 Network Latency
        3. 3.4.1.3 PDR, PS
        4. 3.4.1.4 Low-Power Mode
      2. 3.4.2 Cell Voltage Accuracy
      3. 3.4.3 Temperature Sensing Using TMP61
      4. 3.4.4 Thermistor Multiplexer Timing
      5. 3.4.5 Current Consumption
  10. 4Design and Documentation Support
    1. 4.1 Design Files
      1. 4.1.1 Schematics
      2. 4.1.2 BOM
      3. 4.1.3 Layout Prints
    2. 4.2 Tools and Software
    3. 4.3 Documentation Support
    4. 4.4 Support Resources
    5. 4.5 Trademarks
  11. 5About the Author

3.4.1.3 PDR, PS

To test the robustness of the wireless BMS network, measure the two network key performance indicator (KPI) parameters. The definitions are as follows:

  1. Path Stability (PS): Path stability is the percentage of first time successfully received packets at each WD node divided by the total number of packets transmitted by the WM node.
    1. Metric: PS > 85%
    2. Note: Number of packets must be > 10000
  2. Packet Delivery Rate (PDR): PDR is the percentage of packets successfully received at each WD node divided by the total number of packets transmitted by the WM node. This includes retransmissions needed within the 100ms interval.
    1. Metric: PDR > 99.9%
    2. Note: Number of packets must be > 10000

The three KPI are calculated from the data read by the statistic commands in the wBMS SDK. Calculate PDR of the node n using Equation 3.

Equation 1. PDR = 1 - NumRxMissedPackets n NumTxSuccessPackets

where

  • n is the number of WD nodes

Calculate PS of node n using Equation 3.

Equation 2. PS n = 1 - S u m Retry 1–3 NumTxActualPackets

where

  • NumTxActualPackets is calculated based on NumTxSuccessPackets plus the maximum number of retries for all WD nodes during each transmission
  • NumTxActualPackets indicates the actual number of TX packets sent from RF physical layer

The PS and PDR test results of 30000 packets is shown in Table 3-6. The test results show good network robustness of this setup for 416s cells.

Table 3-6 PS and PDR Test Results
NODE WD0 WD1 WD2 WD3 WD4 WD5 WD6 WD7
NumTxSuccessPackets 30001
NumTxActualPackets 33095
NumRxMissedPackets 0 0 0 0 0 0 0 1
Retry 225 710 560 643 465 341 609 1396
PDR 100% 100% 100% 100% 100% 100% 100% 99.997%
PS 99.320% 97.855% 98.308% 98.057% 98.595% 98.970% 98.160% 95.782%