A Cross-layer approach to optimize the performance of Concurrent Multipath Transfer in wireless transmission

Along with the rapid progress of the network technologies, as well as the vast cost decreasing of the peripherals, terminals with several interfaces have become increasingly common. Therefore, developing methods for enabling the concurrent use of available interfaces is in great demand. Although the Stream Control Transport Protocol (SCTP) has supported multi-homing feature, the simultaneous data transfer over multiple paths is currently not allowed in standard. However, an extension to the SCTP, Concurrent Multipath Transfer (CMT), offers a solution which enable the simultaneous use of multiple interfaces. Besides, wireless network expresses more complicated characters comparing to its counterpart in wired network. For example, the radio link conditions in wireless network are more variable and the paths are instable because of mobility or interference. Therefore, it is worthwhile for us to conduct the research on CMT in wireless networks with a Cross-Layer approach. In this study, two parameters, Frame Error Rate (FER) at the link layer and Round Trip Time (RTT) at the transport layer are used to evaluate the path conditions. Meanwhile, a performance metric, the reordered packet ratio is adopted to represent the problem associated with the reordering in multipath transfer. The simulation results show that the flow distribution algorithm improves the goodput and reduces the reordered packet ratio in multipath transfer. In fact, distinguishing paths by taking the FER into account and sending packets on the fastest path decrease the number of out-of-order packets at the receiver.