A performance analysis model for TCP over multiple heterogeneous paths in 5G networks

The demand for multipath transmission is prominent in 5G networks with the deployment of multiple hierarchical access technologies. However, multipath schemes are still not widely adopted due to many reasons, such as deployment challenges and performance reduction under the circumstances of path heterogeneity. Thus, TCP is still in the dominant position of the transport layer protocol for now and for the foreseeable future. Link asymmetry, such as different latency and different bandwidth of different links, is considered to be the main reasons leading to packet reordering, and further result in TCP performance reduction. However, to the best of knowledge, no one has yet given a theoretical model to analyze the relationship between link asymmetry and TCP multipath performance. In this paper, we present a performance analysis model for TCP over multiple heterogeneous networks, which reveals the effect of link asymmetry on TCP throughput. Both bandwidth and delay asymmetry are taken into consideration in the proposed model. The evaluated throughput using the proposed model can accurately fit the simulation results.