Patent ID: 7817573

Claim:
A communication processor, adapted to perform communications with a plurality of communication devices each of which is provided with identifying information, the communication processor comprising: an instruction transmitter configured to transmit an instruction designating a first segment number indicative of a total number of communication segments to be used to perform communications with the communication devices; a collision number identifier configured to identify a collision number indicative of how many of the communication segments detect a collision between the communication devices when the communications are performed with the communication devices under a condition that each of the communication devices is allocated to one of the communication segments; a segment number identifier configured to identify a second segment number indicative of how many communication segments are required to perform communications with the communication devices without collision, based on the first segment number and the collision number, and to identify a communication failure number indicative of how many of the communication devices failed to perform the communications with reference to the first segment number and the collision number, so that the second segment number is identified with reference to the communication failure number; and a segment number updater configured to update the first segment number with the second segment number, wherein the segment number identifier includes: an estimator configured to prepare different segment numbers, and to obtain estimation values each of which is indicative of how many of the communication devices are capable of performing the communications without collision under a condition that the communication devices indicated by the communication failure number are allocated to the communication segments indicated by an associated one of the different segment numbers; and an evaluator configured to obtain evaluation values by respectively substituting the estimation values and the different segment numbers into an evaluating function which is an increasing function for the evaluation values and a decreasing function for the different segment numbers, the segment number identifier is configured to identify, as the second segment number, one of the different segment numbers with which the highest one of the evaluation values is obtained.