Patent ID: 11968107
Assignee: BAYERISCHE MOTOREN WERKE AKTIENGESELLSCHAFT
Field: Digital communication (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. A method for determining a correctness of an actually received timestamp provided by a first ECU of a communication network of a vehicle using a validator,
wherein the communication network comprises a master clock, the first ECU having a first slave clock, the validator having a second slave clock, and a first communication bus connecting the first ECU, the validator and the master clock to each other, and wherein the first ECU uses a first communication standard having a deterministic scheme,
the method comprising:
synchronizing, at the first ECU, a first time of the first slave clock to a global time of the master clock,
synchronizing, at the validator, a second time of the second slave clock to the global time of the master clock,
predicting, at the validator, a timestamp to be received in an actual communication cycle from the first ECU based on the deterministic scheme of the communication standard used by the first ECU, and
comparing, at the validator, the predicted timestamp with the actually received timestamp from the first ECU,
wherein the comparing, at the validator, the predicted timestamp with the actually received timestamp provided by the first ECU of the communication network comprises:
determining, at the validator, a difference between the predicted timestamp and the actually received timestamp,
comparing the difference to a predefined threshold value, and
upon determining that the difference is smaller than the predefined threshold value, determining the correctness of the actually received timestamp, wherein:
the difference between the global time of the predicted timestamp at the validator and the global time of the actually received timestamp is determined considering a fixed delay between a data acquisition task and a data sending task of the first ECU,
the actually received timestamp at the validator is provided by the first ECU during the data acquisition task, and
the difference between the predicted timestamp and the actually received timestamp is determined using the following formula:

GT2−GT1−Δ+δ, wherein:

GT2 is a global time of providing the actually received timestamp by the first ECU,
GT1 is a global reference time at a start of the actual communication cycle of the first ECU,
Δ is a result received by multiplying a predefined number of slots of the deterministic scheme of the first communication standard used by the first ECU with a fixed duration of the slots, and
δ is the fixed delay between the data acquisition task and the data sending task of the fir st ECU, wherein the actually received timestamp is provided during the data acquisition task by the first ECU.