[Paper Review] Improving Energy Efficiency of MPTCP for Mobile Devices

Yeon-sup Lim, Yung‐Chih Chen+3 more|arXiv (Cornell University)|Jun 17, 2014

Green IT and Sustainability13 references19 citations

TL;DR

This paper proposes eMPTCP, an energy-aware Multi-Path TCP implementation for mobile devices that dynamically selects network paths based on real-time throughput and energy efficiency. Evaluated on a real Android device, eMPTCP reduces energy consumption by up to 15% compared to standard MPTCP while preserving its robustness and availability benefits, outperforming even WiFi-only TCP in energy efficiency under certain conditions.

ABSTRACT

Multi-Path TCP (MPTCP) is a new transport protocol that enables systems to exploit available paths through multiple network interfaces. MPTCP is particularly useful for mobile devices, which usually have multiple wireless interfaces. However, these devices have limited power capacity and thus judicious use of these interfaces is required. In this work, we develop a model for MPTCP energy consumption derived from experimental measurements using MPTCP on a mobile device with both cellular and WiFi interfaces. Using our energy model, we identify an operating region where there is scope to improve power efficiency compared to both standard TCP and MPTCP. We design and implement an improved energy-efficient MPTCP, called eMPTCP. We evaluate eMPTCP on a mobile device across several scenarios, including varying bandwidth, background traffic, and user mobility. Our results show that eMPTCP can reduce the power consumption by up to 15% compared with MPTCP, while preserving the availability and robustness benefits of MPTCP. Furthermore, we show that when compared with TCP over WiFi, which is more energy efficient than TCP over LTE, eMPTCP obtains significantly better performance with relatively little additional energy overhead.

Motivation & Objective

• To understand the energy consumption behavior of MPTCP on mobile devices with multiple wireless interfaces (WiFi and cellular).
• To identify operating conditions where MPTCP is more energy-efficient than single-path TCP over WiFi or LTE.
• To design and implement an energy-aware MPTCP variant (eMPTCP) that optimizes path selection for energy efficiency.
• To evaluate eMPTCP under real-world conditions, including varying bandwidth, mobility, and background traffic.
• To demonstrate that energy efficiency can be improved without sacrificing MPTCP’s key benefits of robustness and availability.

Proposed method

• Developed an experimental energy model for MPTCP based on real measurements from a Samsung Galaxy S3 smartphone using both WiFi and LTE interfaces.
• Used regression analysis to derive a predictive model of MPTCP energy consumption, validated with experimental data showing less than 17% error.
• Designed eMPTCP to monitor real-time path characteristics (throughput, signal quality) and select subflows based on expected energy efficiency.
• Implemented eMPTCP as a kernel-level patch on Android, enabling dynamic path switching based on the energy model.
• Evaluated eMPTCP across multiple scenarios: varying download sizes, dynamic bandwidth, radio interference, and user mobility.
• Compared eMPTCP against standard MPTCP and TCP over WiFi in terms of energy consumption, throughput, and connection robustness.

Experimental results

Research questions

• RQ1 How much energy does MPTCP consume compared to single-path TCP over WiFi or LTE?
• RQ2 Are there specific network conditions where MPTCP is more energy-efficient than single-path TCP?
• RQ3 Can MPTCP’s energy efficiency be improved through intelligent path selection without sacrificing robustness?
• RQ4 What are the tradeoffs between energy efficiency and performance in multi-path TCP under real-world mobility and interference?
• RQ5 How does eMPTCP compare to standard MPTCP and WiFi-only TCP in terms of energy consumption and performance?

Key findings

• The energy model for MPTCP accurately predicts measured energy consumption with less than 17% error, enabling reliable optimization.
• MPTCP is generally less energy-efficient than WiFi-only TCP due to the high tail energy cost of cellular interfaces, especially in low-throughput scenarios.
• An operating region exists—characterized by high available bandwidth and moderate transfer sizes—where MPTCP is more energy-efficient than single-path TCP.
• eMPTCP reduces energy consumption by up to 15% compared to standard MPTCP across diverse mobility and traffic conditions.
• eMPTCP achieves better performance than WiFi-only TCP with only a small energy overhead, and in some cases even less energy consumption.
• eMPTCP preserves MPTCP’s robustness and availability benefits by maintaining multiple subflows even when switching paths based on energy efficiency.