PNX Definition
Phone · Near · eXecute — Three-layer architecture and technical boundaries
Naming #
PNX consists of three letters, each corresponding to a layer of the technical architecture. Together they form a complete decoupled keyless entry flow.
P = Phone (Phone Verification)
The phone serves as a digital identity token. Once Bluetooth connection is established, the module verifies the phone's identity via UUID, confirming "you are an authorized user."
- Input: Phone BLE broadcast signal
- Process: Module scans nearby BLE devices, matches UUID whitelist
- Output: Verification passed / not passed
- Timing: Typically completes within 1-3 seconds
- UX: Seamless, no need to take out phone
N = Near (Proximity Confirmation)
The system determines physical distance between user and vehicle via Bluetooth RSSI signal strength. Only when entering the preset threshold range does the system determine the user is "present" and prepare for execution.
- Input: Real-time RSSI value of verified phone
- Process: Continuous RSSI monitoring, comparison with preset threshold
- Output: Within effective range (micro-switch energized) / not within range
- Thresholds: Unlock -65dBm, Lock -80dBm (recommended)
X = eXecute (Manual Execution)
With both verification and confirmation completed automatically, execution control is handed to the user. Pressing the door handle micro-switch triggers the system to send the unlock command.
- Input: Physical press signal from micro-switch
- Prerequisite: Layer 1 verified and Layer 2 confirmed present
- Process: Edge detection of switch signal, debounce, then send unlock command
- Output: Vehicle control domain executes unlock / powers on
- Timing: Typical delay from press to execution ≤ 200ms
Extended X Meanings #
X carries two extended meanings, naturally emerging in technical breakdowns:
- eXact (Precise): Precise control, no false triggers, no lockouts — precise to the moment the user presses
- eXplore (Explore): Phone approaches, infinite possibilities. PNX is not just a key, but an entry point to smart mobility
In external communications, eXecute is the primary meaning; eXact and eXplore enrich X's connotations in technical breakdowns without overshadowing the main message.
Technical Boundary #
PNX is not an independent communication protocol. PNX is built on the BLE protocol stack, constructing an application-layer interaction paradigm above BLE's link layer. This means:
- PNX does not replace BLE, but is built on BLE
- PNX does not define new radio communication specifications, but defines "when to allow user manual trigger"
- PNX stands alongside UWB, NFC, and BLE proximity mode as an application-layer unlocking approach
Differences from NFC / UWB #
| Feature | UWB | NFC | BLE Proximity | PNX |
|---|---|---|---|---|
| Protocol | IEEE 802.15.4z | ISO/IEC 14443 | BLE 4.2/5.x | BLE 5.x (App Layer) |
| Verification | Phone UWB chip | Phone/Card tap | Phone BLE | Phone BLE |
| Presence | ToF multi-point | Tap detection | RSSI single-point | RSSI threshold |
| Trigger | Automatic | User manual tap | Automatic | User manual button |
| Retrofit | Impossible | Very hard | Easy | Easy |
| Legacy cars | 0% | <5% | >95% | >95% |
| Experience | Fully auto, precise | Manual, reliable | Fully auto, fluctuates | Auto+manual, controllable |
Core Design Principles #
Secure by Default
The system's default state is "not connected, not responding, not unlocked". Only when all three-layer conditions are explicitly met is the next step allowed.
User Sovereignty
The final decision to execute unlocking is always triggered by user's physical action. The system can suggest and prepare, but cannot replace the user pressing the switch.
Backward Compatible
PNX does not mandate replacing proximity mode. Users can toggle between "proximity mode" and "PNX mode" via the APP with one click.