Yong-Seok Park

MPMTP: Multipath Multimedia Transport Protocol using Systematic Raptor Codes over Wireless Networks

This paper presents a multipath multimedia transport protocol (MPMTP), which exploits path diversity over heterogeneous wireless networks. The goal of MPMTP is to provide a seamless high-quality video streaming service by using multiple wireless networks simultaneously. In MPMTP, systematic Raptor codes are adopted to mitigate video quality degradation caused by wireless channel errors as well as to alleviate a head-of-line blocking problem in multipath environments, and their encoding parameters such as code rate, symbol size, and the number of source symbols are determined on the fly by considering the wireless channel state, Raptor encoding and decoding complexity, and receiver buffer occupancy. Furthermore, MPMTP performs packet scheduling considering not only wireless network conditions but also packet payload characteristics for smooth video playback. The proposed MPMTP is fully implemented in a Linux kernel and examined over real wireless network environments.

Impact of traffic splitting on the delay performance of MPTCP

MPTCP is a promising transport technique to boost throughput of wireless multi-homed device by supporting multiple concurrent transmissions through heterogeneous wireless interfaces. As the number of concurrent subflows increase, MPTCP can achieve a linearly increasing throughput performance, but it is unclear how much improvement in the end-to-end delay performance can be attained from additional subflows. In this paper, we develop an analytical framework to understand the end-to-end delay performance of MPTCP that accounts for TCP dynamics and subflow interactions. Interestingly, it turns out that the delay performance can be even degraded with additional subflows. Considering MPTCP in heterogeneous wireless networks of Wi-Fi and LTE, we formulate a cost minimization problem subject to the end-to-end delay constraint. Based on the insight obtained from our model, we approximate the problem and develop a greedy scheme that splits traffic to minimize the cost while satisfying the delay constraints. Through simulations, we demonstrate that our proposed scheme outperforms the conventional MPTCP, and significantly improves the delay performance while lowering the user cost.

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We propose E

PA: Energy, usage (

PA, an adaptive LTE/WiFi network interface activation algorithm with supporting system design and multi-attribute cost function for smartphones file transfer services (e.g., downloading a movie file). E

), and performance-aware LTE-WiFi adaptive activation scheme for smartphones

PAs cost function incorporates battery life (energy), data usage quota (

QoS-supporting video streaming system with minimum data service cost over heterogeneous wireless networks

), and expected file transfer completion time (performance) simultaneously, and is motivated by the growing sensitivity of todays smartphone users to these attributes. Each time the individual attributes are calculated and updated, E

PIMM: Packet Interval-Based Power Modeling of Multiple Network Interface-Activated Smartphones

PA selects one of the three modes that minimizes the overall cost: (i) activation of both LTE and WiFi interfaces for parallel data transfer; (ii) LTE interface activation only; or (iii) WiFi interface activation only. The primary benefit of the E

A new efficient scheduling algorithm in Bluetooth piconet

PA is that it enables the smartphone to always operate in the “best” mode without the need for users manual control; the energy saving mode if the remaining battery energy is becoming nearly depleted; the cost-saving mode if the remaining data quota is almost running out; or, the maximum throughput mode if remaining data quota and battery life are both sufficient. Our multi-attribute cost model also takes into account the overheads (delays and energy consumption) associated with network interface turn-on/off and switching, as they impact the estimations of both performance (transfer time) and energy (battery life) attributes. Simulation results show that E

BattTracker: Enabling energy awareness for smartphone using Li-ion battery characteristics

PA indeed chooses the “best” operational mode by maintaining dynamic balance among transfer time, energy consumption, and service charge.

Adaptive interest adjustment in CCN flow control

This paper presents a video streaming system that supports quality-of-service by effectively consolidating multiple physical paths in a cost-effective way over heterogeneous wireless networks. In the proposed system, the fountain encoding symbols of compressed video data are transmitted through multiple physical paths concurrently to overcome the limitation of single path transmission and harmonize multiple physical paths with diverse characteristics effectively, and the number of transmitted packets is determined by considering the requested quality-of-service of video streaming and the data service cost. The proposed system is fully implemented in Java and C/C++, and tested over real WLAN and LTE networks. Experimental results are provided to demonstrate the performance improvement of the proposed system.