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

Claim 4:
5. A validator configured to determine a correctness of an actually received timestamp provided by a first ECU of a communication network of a vehicle,
wherein the communication network comprises a master clock, the first ECU having a first slave clock, and a first communication bus configured to connect the first ECU, the validator and the master clock to each other,
wherein the first ECU uses a first communication standard having a deterministic scheme, and
wherein a first time of the first slave clock is synchronized to a global time of the master clock,
the validator comprising:
a second slave clock, wherein a second time of the second slave clock is synchronized to the global time of the master clock, and
wherein the validator is configured to:
predict 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
compare the predicted timestamp with an actually received timestamp from the first ECU,
wherein to compare the predicted timestamp with the actually received timestamp from the first ECU, the validator is further configured to:
determine a difference between the predicted timestamp and the actually received time stamp,
compare the difference to a predefined threshold value, and
upon determining that the difference is smaller than the predefined threshold value, determine 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 first ECU, wherein the actually received timestamp is provided during the data acquisition task by the first ECU.