DIGITAL COMMUNICATION SYSTEM

摘要

PROBLEM TO BE SOLVED: To improve reliability in data transmission while minimizing processing delay by performing retransmission processing caused by an error by detecting the transmission error while adding a code for detecting the transmission error for each piece of cell data. SOLUTION: A speech path setting/opening.band managing part 12 of B-CS manages the number of blocks in a TDMA frame to be allocated to plural B-RM. Radio LLC parts 5 and 8 control retransmission caused by the transmission error in a radio band while securing allowable delay time and radio MAC part 6 and 7 perform processing to return a retransmission request by detecting the transmission error for the unit of each piece of cell data loaded on the user channel of the TDMA frame. This retransmission processing is repeatedly performed until the delay time maximum and allowable for service communicated through a virtual communication path and over this allowable time, retransmission is stopped by deciding retransmission time-out. Thus, retransmission processing can be executed on the side of transmission while surely grasping the presence/absence of error.