MULTICAST COMMUNICATION SYSTEM AND MULTICAST COMMUNICATION METHOD, DATA COMMUNICATION EQUIPMENT AND DATA COMMUNICATION METHOD, AND AUTOMATIC SETTING METHOD FOR THE NUMBER OF WAITING FRAME IN THE MULTICAST COMMUNICATION SYSTEM

摘要

PROBLEM TO BE SOLVED: To provide a multicast communication system employing an SR-ARQ system that can realize a high throughput by excluding useless frame re- transmission independently of the number of received stations. SOLUTION: A round trip delay RTFc measured for each transmission reception station is compared with the number RTFm of a time slot required for a transmission station to finish the reception of a reply from all reception stations and the delay which is larger is set for a round rip RTF for SR-ARQ re-transmission control. As a result, useless frame re-transmission owing to re-transmission of frames without awaiting the reply from all reception sections can be reduced thus, the multi-cast communication system with higher transmission efficiency can be provided.