RF Communication and Wireless Mini-Networks
To conclude this book and look ahead to the near future, I will briefly describe the radio-frequency links and mini-networks mentioned in Chapter 7, better known under the term ‘wireless’. The ‘internal’ and ‘external’ aspects of these applications will be considered. As mentioned above, the most popular ones have names such as Bluetooth, Zigbee, IEEE 802.11, NFC, RKE, PKE, passive go, TPMS, TiD, etc.
11.1 Radio-Frequency Communication: Internal
Many internal applications in vehicles also use radio-frequency media for digital communications and for connection at some point to other networks (controller area network (CAN), local interconnect network (LIN), etc.) of a vehicle or other industrial system.
Let us start with the most conventional kind of radio-frequency receiver, namely the AM/FM/digital radio, which may or may not have antennae incorporated in the windscreen or in the rear screen de-icing system. These systems are entirely conventional, except for those using voice commands (voice synthesis and/or recognition) for tuning and volume, with control via I2C, LIN or CAN buses, etc.
11.1.2 Immobilizer or engine start prevention
The immobilizer function consists in preventing the starting of the engine of a vehicle (not to be confused with an anti-theft function), using RF transponders (usually operating on an low-frequency (LF) carrier at 125 kHz). These systems have been well known for several years.