Patent ID: 8934351
Filing Date: 2015-01-13
Classification: H04L

Abstract:
1. A communication apparatus in a communication system in which a plurality of communication apparatuses repeatedly perform transmission and reception of data every predetermined communication period repeated at regular intervals, and communication in the communication system is performed by a communication scheme in which simultaneous transmission from a plurality of devices is not allowed, the communication apparatus comprising: a retransmitting unit configured to perform a retransmitting process of data when a transmission error of the data is detected; a retransmission control unit configured to inhibit the retransmitting process in a corresponding communication period if a number of times of detection or a duration time of a transmission error detected within one period of the communication period is larger than a first threshold value, and to release an inhibition of the retransmitting process when the corresponding communication period ends and a next communication period begins; and an abnormality detecting unit configured to detect the number of times of detection or a duration time of a transmission error detected over a series of communication periods during a time period other than a time period in which the retransmitting process is inhibited by the retransmission control unit, to determine that communication abnormality has occurred when the detected number of times of detection or the detected duration time is larger than a second threshold value which is higher than the first threshold value, to inhibit the retransmitting process when abnormality is detected, and to not release inhibition of the retransmitting process even when a communication period in which the transmission is inhibited ends and the next communication period begins.