Vehicular communication device

1. A vehicular communication device used for a vehicle, comprising:

a reception section that receives, from a periphery vehicle equipped with a narrow area communicator for performing vehicle interior communication, a communication performance index representing performance of the narrow area communicator;

a reference value setup section that successively sets a reference value as a criterion for the communication performance index, based on the communication performance indexes received by the reception section from a plurality of the periphery vehicles;

an acquisition section that acquires the communication performance index for a targeted narrow area communicator, the targeted narrow area communicator being the narrow area communicator that is targeted at anomaly determination; and

an anomaly determination section that determines anomaly of the targeted narrow area communicator, based on comparison between the reference value set by the reference value setup section and the communication performance index acquired by the acquisition section for the targeted narrow area communicator.

2. The vehicular communication device according to claim 1 , wherein:

the acquisition section acquires any one of the communication performance indexes received by the reception section from the plurality of periphery vehicles as the communication performance index for the targeted narrow area communicator.

3. The vehicular communication device according to claim 2 , further comprising:

a first anomaly notification processing section that, when the targeted narrow area communicator is determined to be abnormal by the anomaly determination section, uses a specified communicator to notify a center that the narrow area communicator of the periphery vehicle, as the targeted narrow area communicator, is abnormal.

4. The vehicular communication device according to claim 1 , wherein:

the vehicular communication device includes a narrow area communicator; and

the acquisition section acquires, as the communication performance index for the targeted narrow area communicator, the communication performance index for the narrow area communicator that is included in the same vehicular communication device as the acquisition section is included.

5. The vehicular communication device according to claim 4 , further comprising:

a second anomaly notification processing section that, when the targeted narrow area communicator is determined to be abnormal by the anomaly determination section, uses a specified communicator to notify a center that the narrow area communicator of a subject vehicle is abnormal, the subject vehicle being the vehicle for which the targeted narrow area communicator is used.

6. The vehicular communication device according to claim 4 , wherein

the narrow area communicator reads payment information from a storage medium storing the payment information used to pay charge for the vehicle when using a road facility,

the vehicular communication device further comprising:

a wide area communicator that communicates with a center to perform a process concerning the charge via a communication network;

a storage unit that is writable;

a storage control section that, when the narrow area communicator reads the payment information, stores the read payment information in the storage unit; and

a transmission control section that causes the wide area communicator to transmit the payment information read by the narrow area communicator to the center,

wherein

when, after the storage control section stores the payment information in the storage unit, the anomaly determination section determines anomaly of the narrow area communicator until ignition-off and there arise needs to read the payment information, the transmission control section transmits the payment information stored in the storage unit to the center instead of the payment information read by the narrow area communicator.

7. The vehicular communication device according to claim 1 , wherein:

the reception section receives the communication performance index and an altitude of the periphery vehicle transmitting the communication performance index;

the vehicular communication device further comprises an altitude detector to detect an altitude of a subject vehicle, the subject vehicle being the vehicle for which the vehicular communication device is used; and

the reference value setup section successively sets the reference value by using, out of the communication performance indexes acquired along with the altitudes by the reception section from the plurality of periphery vehicles, the communication performance index received along with the altitude whose difference from the altitude of the subject vehicle detected by the altitude detector is within an approximate altitude range.

8. A vehicular communication device used for a vehicle, comprising:

a wide area communicator that receives, from a periphery vehicle equipped with a narrow area communicator for performing vehicle interior communication, a communication performance index representing performance of the narrow area communicator; and

a controller having a processor and memory configured to:

successively set a reference value as a criterion for the communication performance index, based on communication performance indexes received by the wide area communicator from a plurality of periphery vehicles;

acquire the communication performance index for a targeted narrow area communicator, the targeted narrow area communicator being the narrow area communicator that is targeted for anomaly determination; and

determine an anomaly of the targeted narrow area communicator, based on comparison between the set reference value and the acquired communication performance index for the targeted narrow area communicator.