MULTI-CAST COMMUNICATION SYSTEM AND METHOD, AND DATA COMMUNICATION UNIT AND DATA COMMUNICATION METHOD

摘要

PROBLEM TO BE SOLVED: To conduct re-transmission control to warrant quality and reliability of transmission data in the case of data communication adopting the multi-cast system. SOLUTION: A data transmission terminal transmits a succeeding data frame without awaiting reception of reply frames from all data reception terminals. Furthermore, an FBI included in a current reply frame and unprocessed FBIs up to now are listed in the older sequence to prioritize re-transmission requests thereby deciding a succeeding FFI. Thus, the re-transmission control is conducted while excluding redundancy to attain a high throughput. This method is especially effective in the direct communication where a delay time to obtain transmission confirmation is comparatively small.