Patent ID: 8611229
Filing Date: 2013-12-17
Classification: H04L,H04W

Abstract:
1. A retransmission method in a multicast system including a base station and at least one user apparatus, the method comprising: when the user apparatus has a service quality greater than or equal to a predetermined threshold, transmitting to the base station a first message showing a data packet with an error detected later as between two errors detected in a plurality of data packets received in the user apparatus; receiving, from the base station, a retransmission group including one or more data packets, the one or more data packets forming one retransmission data packet obtained by performing exclusive or (XOR) calculation, the retransmission group is formed using consecutive data packets in the plurality of data packets, and a start position and an end position of the one or more data packets being determined based on the first message; and when the service quality of the user apparatus is lower than the predetermined threshold, disallowing the user apparatus from transmitting the first message showing a data packet with an error detected later as between two errors detected in a plurality of data packets received in the user apparatus having the lower service quality.