Goodput improvement for multipath transport control protocol in cooperative relay-based wireless networks

Multipath transport control protocol (MPTCP) standardised by Internet Engineering Task Force offers a promising solution to support simultaneous delivery of transport control protocol packets over multiple interfaces of multi-radio mobile devices. Even when there is no multiple access coverage, it is still possible to enable multipath transmission by involving mobile devices in vicinity as cooperative relays. However, the available bandwidth provided by relays can be highly varying because of wireless channel fading or dynamic local traffic load. Although MPTCP can pool the available bandwidths of multiple paths, it is challenging to address the dynamics of the cooperative wireless network and ensure a stable performance. In this study, the authors extend MPTCP for the long-term evolution network with cooperative relays by an integrated solution in three aspects, namely, subset `sum-based relay selection´, `adaptive congestion control´ and `differentiated packet forwarding´. Extensive simulations in NS-3 show that the proposed modules can achieve a stable aggregate throughput by engaging a small number of relays and significantly improve the goodput in various scenarios.