On the other hand, on the 3 G wireless network, from data-resource-end to data-receiving-end a message need to some intermediate nodes to forward. Intermediate node have three continuous operation on a forwarding message, that is receiving, temporary storage and sending. When a data message can’t successful transmission to the destination node because of error lost package, the data link layer will use the retransmission method for data. But , because the 3 G network node has mobility, competition of channel resources in the nodes, leding to 3G network have some uncertain problems in link quality[3].