摘要

The link performance is highly unpredictable and the connections are broken frequently in opportunistic networks (Oppnets). The transmission control protocol will perform badly in Oppnets because the end-to-end connection always needs to be reconstructed and data need to be retransmitted from the original sender again through the reconstructed connection. To solve this problem, the study investigates the principles of on-time and at-one-time delivery, in which %26apos;on-time%26apos; means to transmit data to the receiver during a pre-scheduled time period and %26apos;at-one-time%26apos; means to transmit each piece of data from the sender just once. Based on the principles, the designed adaptive transmitting platform (ATPOO) supports the on-time and at-one-time delivering capacities in Oppnets. In ATPOO, the authors separate the transmitting process into macro-and microstages. The macro-stage deals with the end-to-end transmission quality of service; the micro-stage focuses on the transmission between adjacent nodes along with the pre-constructed delivering path. The proposed ATPOO based on the delay-tolerant network (DTN) has been implemented in this study. The experimental results show that the designed ATPOO performs the highest successful delivery ratio of 97% over complex and unpredictable network environments while the ratios of best effort, S-FTP and DTN methods are 81, 76 and 89%, respectively.

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