SPLA002 July   2026 CC2755R10

 

  1.   1
  2.   Abstract
  3. 1Introduction
  4. 2Profile of CC2755
  5. 3Demonstration of the TI Door Lock Solution
  6. 4Overview of Channel Sounding Technology
    1. 4.1 Basic Principles
    2. 4.2 Ranging method
    3. 4.3 Accuracy and Reliability
  7. 5Overall System Design
    1. 5.1 Overall System Architecture
      1. 5.1.1 Power Design Guidance
        1. 5.1.1.1 Linear Regulator Architecture
        2. 5.1.1.2 Buck Converter Architecture
      2. 5.1.2 Motor Driver Design Guidance
  8. 6CC2755-Based Ranging Implementation
    1. 6.1 Keyless Entry Logic
      1. 6.1.1 Basic Configuration and Calibration
      2. 6.1.2 Real-Time Ranging Process
      3. 6.1.3 Frictionless Unlocking Decision Logic
        1. 6.1.3.1 Intent Judgement
      4. 6.1.4 Unlock Execution and Feedback
      5. 6.1.5 Exception Handling
    2. 6.2 RF Hardware Design
      1. 6.2.1 Key End Solution Selection
      2. 6.2.2 Door Lock End Solution Selection
    3. 6.3 Hardware Reference Design
    4. 6.4 Single Antenna and Multi-Antenna
      1. 6.4.1 Impact of Antenna Quantity on Channel Sounding Ranging Performance
      2. 6.4.2 The Role of Antennas in Phase-Based Ranging
      3. 6.4.3 Analysis of Advantages and Disadvantages of Single-Antenna Configuration
        1. 6.4.3.1 Advantages: Simplicity and Low Cost
        2. 6.4.3.2 Disadvantages: Limited by Multiple Interference Factors
      4. 6.4.4 Analysis of Advantages and Disadvantages of Multi-Antenna Configuration
        1. 6.4.4.1 Advantage 1: Anti-Multipath Capability Brought by Spatial Diversity
        2. 6.4.4.2 Advantage 2: Alleviating Antenna Orientation Sensitivity Issues
        3. 6.4.4.3 Advantage 3: Dual Enhancement of Accuracy and Robustness
        4. 6.4.4.4 Disadvantages: Increased Hardware Complexity and Cost
      5. 6.4.5 Precautions for Dual-Antenna Design
    5. 6.5 Test results
      1. 6.5.1 Hardware configuration
      2. 6.5.2 Software Configuration:
      3. 6.5.3 Environment Setup:
    6. 6.6 Power consumption simulations
  9. 7Summary
  10. 8References

6.1.3.1 Intent Judgement

Unlocking is not executed merely because the distance is <1.2m; the following conditions must be met simultaneously:

  • Continuous Approach to the Door: The last 3 ranging values are strictly monotonically decreasing (distance shortening), ruling out wandering or walking past the door.
  • Standstill Verification: After entering the action zone, the distance fluctuation is <0.15m and the duration lasts for ≥0.8 seconds (indicating the user actively stopped to prepare to open the door).
  • Consistent Phone Attitude: The smartphone gyroscope shows a near-horizontal orientation and the acceleration is stable (ruling out swinging the phone in hand or bumping inside a bag).
  • Security Lockout: If the action zone is entered 3 consecutive times without unlocking (the user just walked past), the ranging request will be temporarily blocked for 2 minutes.