Open Access

Power-Efficient Communication Protocol for Integrated WWAN and WLAN

  • Su Kyoung Lee1Email author,
  • Won Sik Chung1,
  • Kun Ho Hong1 and
  • Nada Golmie2
EURASIP Journal on Wireless Communications and Networking20072008:342141

DOI: 10.1155/2008/342141

Received: 27 February 2007

Accepted: 31 October 2007

Published: 8 November 2007


One of the most impending requirements to support a seamless communication environment in heterogeneous wireless networks comes from the limited power supply of small-size and low-cost mobile terminals as in stand-alone WLANs or cellular networks. Thus, it is a challenge to design new techniques so that mobile terminals are able to not only maintain their active connection as they move across different types of wireless networks, but also minimize their power consumption. There have been several efforts aimed at having mobile devices equipped with multiple interfaces connect optimally to the access network that minimizes their power consumption. However, a study of existing schemes for WLAN notes that in the idle state, a device with both a WLAN and a WWAN interface needs to keep both interfaces on in order to receive periodic beacon messages from the access point (AP: WLAN) and downlink control information from the base station (WWAN), resulting in significant power consumption. Therefore, in this paper, we propose a power-efficient communication protocol (PCP) that includes turning off the WLAN interface after it enters the idle state and using the paging channel of WWAN in order to wake up the WLAN interface when there is incoming long-lived multimedia data. This scheme is known to limit the power consumption, while at the same time, it makes use of the paging channel in cellular networks. Further, our proposed scheme is designed to avoid repeatedly turning on and off WLAN interfaces, that consumes a significant amount of power. We propose turning on the WLAN interface when the number of packets in the radio network controller (RNC)'s buffer reaches a certain threshold level. The tradeoffs between the power saving and the number of packets dropped at the buffer are investigated analytically through the study of an on/off traffic model. Simulation results for scenarios of interest are also provided.

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Authors’ Affiliations

Department of Computer Science, Engineering College, Yonsei University
National Institute of Standards and Technology


© SuKyoung Lee et al. 2008

This article is published under license to BioMed Central Ltd. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.