Technology
The ASG protocol
How ASG moves every control signal in the vehicle: one shared medium, divided by frequency, with no bus to arbitrate and no schedule to keep.
In one sentence The ASG protocol carries all in-vehicle control traffic on a single shared channel, divided by frequency into parallel carriers rather than by time slot or message arbitration.
One channel, split by frequency
Every module transmits on the same medium at the same time, separated in frequency. A modified OFDM scheme gives each module its own carrier, a diad, and every symbol carries a synchronisation element so the whole channel stays aligned.
The consequence is the one that matters for a control system: channel capacity grows with carriers, not with time. Adding a module consumes a carrier; the 1 ms window does not move.
The seven layers
Titles are from the ASG protocol description, physical to application. Each lights as you scroll.
- 1 Physical Modified OFDM. Each module carries a frequency identity, a diad, on one shared medium.
- 2 Frame The frame descriptor: which module owns each value, and its frequency identity.
- 3 Network One broadcast domain. Every value has exactly one writer; every module reads all.
- 4 Transport The master clock commits the shared information window, every 1 ms.
- 5 Session Convolutional, error-resistant coding, and its matching decode.
- 6 Presentation Redundancy and integrity protection for the committed state.
- 7 Application Features run in parallel against the one committed vehicle state.
Physical-layer parameters
| Scheme | Modified OFDM | A few parallel carriers on one shared medium |
|---|---|---|
| Subcarriers | 2 to 6 | One carrier is a module’s frequency identity (a diad) |
| Start frequency | 4 MHz | |
| Modulation | Differential phase-shift keying | |
| Bits per symbol | 2 to 5 | Every symbol also carries a synchronisation element |
| Signal power | ≤ 350 mW | Total across the channel |
| Medium | Twisted pair, or power line | PLC over 12 / 24 / 48 V |
| Descriptors | up to 8 | Frame formed to a time-triggered scheme |
From the ASG protocol description. These are design parameters of the physical layer, not performance claims.
Descriptor and single writer
The frame descriptor is the protocol’s unit of ownership: it names which module owns each value and its frequency identity. Every module receives the whole frame.
On the network, ASG is a single broadcast domain. Every signal has exactly one writer and every module reads all of them, so there is no addressing to resolve and no contention to arbitrate.
Questions
Is ASG based on OFDM?
It uses a modified OFDM scheme: a small number of parallel carriers, each one a module’s frequency identity, with a synchronisation element in every symbol.
Why frequency-division rather than time slots or arbitration?
Because then the channel time does not depend on how many modules are on it. Up to about twenty modules, adding one consumes a carrier and the 1 ms window is unchanged. CAN arbitrates for the bus; LIN and FlexRay divide it in time; ASG divides it in frequency.
Which ISO standard does “ISO-compliant” refer to?
The protocol is structured to the seven-layer ISO model. The specific standard reference, and any functional-safety assessment, are still to be confirmed.
Can other buses connect to ASG?
Yes. The zone module translates CAN, LIN and serial (USART) traffic itself: it reads the message, synchronises it into the shared vehicle state, and replies in the original format. That translation is built into the module, so a domain-by-domain transition needs no separate gateway.