Concurrent Multipath Transfer: Scheduling, Modelling, and Congestion Window Management

Known as smartphones, multihomed devices like the iPhone and BlackBerry can simultaneously connect to Wi-Fi and 4G LTE networks. Unfortunately, due to the architectural constraints of standard transport layer protocols like the transmission control protocol (TCP), an Internet application (e.g., a file transfer) can use only one access network at a time. Due to recent developments, however, concurrent multipath transfer (CMT) using the stream control transmission protocol (SCTP) can enable multihomed devices to exploit additional network resources for transport layer communications. In this thesis we explore a variety of techniques aimed at CMT and multihomed devices, such as: packet scheduling, transport layer modelling, and resource management. Some of our accomplishments include, but are not limited to: enhanced performance of CMT under delay-based disparity, a tractable framework for modelling the throughput of CMT, a comparison of modelling techniques for SCTP, a new congestion window update policy for CMT, and efficient use of system resources through optimization. Since the demand for a better communications system is always on the horizon, it is our goal to further the research and inspire others to embrace CMT as a viable network architecture; in hopes that someday CMT will become a standard part of smartphone technology

Energy Efficient Multipath TCP for Mobile Devices

Most mobile devices today come with multiple access interfaces, e.g., 4G and WiFi. Multipath TCP (MP-TCP) can greatly improve network performance by exploiting the connection diversity of multiple access interfaces, at the expense of higher energy consumption. In this paper, we design MP-TCP algorithms for mobile devices by jointly considering the performance and energy consumption. We consider two main types of mobile applications: realtime applications that have a fixed duration and file transfer applications that have a fixed data size. For each type of applications, we propose a two-timescale algorithm with theoretical guarantee on the performance. We present simulation results that show that our algorithms can reduce energy consumption by up to 22% without sacrificing throughput compared to a baseline MP-TCP algorithm

Performance of TCP/UDP under Ad Hoc IEEE802.11

TCP is the De facto standard for connection oriented transport layer protocol, while UDP is the De facto standard for transport layer protocol, which is used with real time traffic for audio and video. Although there have been many attempts to measure and analyze the performance of the TCP protocol in wireless networks, very few research was done on the UDP or the interaction between TCP and UDP traffic over the wireless link. In this paper, we tudy the performance of TCP and UDP over IEEE802.11 ad hoc network. We used two topologies, a string and a mesh topology. Our work indicates that IEEE802.11 as a ad-hoc network is not very suitable for bulk transfer using TCP. It also indicates that it is much better for real-time audio. Although one has to be careful here since real-time audio does require much less bandwidth than the wireless link bandwidth. Careful and detailed studies are needed to further clarify that issue.Comment: 9 pages, 5 figures, ICT 2003 (10th International Conference on Telecommunication

A Markovian Approach to Multipath Data Transfer in Overlay Networks

n/