Block communication method and block communication system, block transmitting apparatus and block receiving apapratus and block receiver-transmitter

A packet transmission method for transmitting packets classified according to a quality of service (QoS) requirement from a transmitting node to a receiving node is provided. In the transmitting node, the steps of selecting sequentially a QoS class; dividing a queued packet to be transmitted belonging to the selected class into a plurality of predetermined data units, and transmitting one of the obtained predetermined data units; and applying a transmitter-side retransmission control process to the data unit to be transmitted when the selected class is a QoS class specified for data type packets are provided. In the receiving node, the steps of: receiving sequentially the data units transmitted from the transmitting node; assembling a plurality of received data units to decompress the original packet for each QoS class; and applying a receiver-side retransmission control process to the received data units to be assembled when the received data unit belongs to one of the QoS classes specified for the data type