| 摘要 |
PURPOSE: A method for re-transmitting video data is provided to divide re-transmitted video data for transmission, and to regulate the size of the video data, so as to prevent the deterioration of use efficiency of channel bandwidth and enhance the efficiency of video transmission. CONSTITUTION: If an adaptation layer-3(AL3) transmission entity(400) transmits a sequence number(V(S)) of I-PDU(Protocol Data Unit) to be included in the I-PDU(S10), an AL3 receiving entity(401) checks whether a presently transmitted serial number(N(S)) of I-PDU is equal to a sequence number(V(R)) of I-PDU to be received. If equal, the AL3 receiving entity(401) normally performs an operation to receive a next I-PDU. If the transmitted N(S) of I-PDU is not equal to the V(R) of the AL3 receiving entity(401), the AL3 receiving entity(401) delivers a re-transmission request message to the AL3 transmission entity(400)(S20). The AL3 transmission entity(400) checks whether the I-PDU of a corresponding sequence number exists in a memory(Bs), and re-transmit a corresponding I-PDU(S30). If the corresponding I-PDU does not exist in the memory(Bs), the AL3 transmission entity(400) notifies the AL3 receiving entity(401) of a re-transmission unavailable message. The AL3 receiving entity(400) suspends a self timer regardless of the availability/unavailability of re-transmission, and receives a next I-PDU.
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