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IEICE TRANSACTIONS on Communications

An Implementation Design of a WLAN Handover Method Based on Cross-Layer Collaboration for TCP Communication

Yuzo TAENAKA, Kazuya TSUKAMOTO, Shigeru KASHIHARA, Suguru YAMAGUCHI, Yuji OIE

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Summary :

In order to prevent the degradation of TCP performance while traversing two WLANs, we present an implementation design of an inter-domain TCP handover method based on cross-layer and multi-homing. The proposed handover manager (HM) in the transport layer uses two TCP connections previously established via two WLANs (multi-homing) and switches the communication path between the two connections according to the handover trigger and the comparison of new/old APs. The handover trigger and comparison are conducted by assessing the wireless link quality using the frame-retry information obtained from the MAC layer (cross-layer). In a previous study, we proposed a preliminary concept for this method and evaluated its functional effectiveness through simulations. In the present study, we design an implementation considering a real system and then examine the effective performance in a real environment because a real system has several system constraints and suffers from fluctuations in an actual wireless environment. Indeed, depending on the cross-layer design, the implementation often degrades the system performance even if the method exhibits good functional performance. Moreover, the simple assessments of wireless link quality in the previous study indicated unnecessary handovers and inappropriate AP selection in a real environment. Therefore, we herein propose a new architecture that performs cross-layer collaboration between the MAC layer and the transport layer while avoiding degradation of system performance. In addition, we use a new assessment scheme of wireless link quality, i.e., double thresholds of frame retry and comparison of frame retry ratio, in order to prevent handover oscillation caused by fluctuations in the wireless environment. The experimental results demonstrate that the prototype system works well by controlling two TCP connections based on assessments of wireless link quality thereby achieving efficient inter-domain TCP handover in a real WLAN environment.

Publication
IEICE TRANSACTIONS on Communications Vol.E96-B No.7 pp.1716-1726
Publication Date
2013/07/01
Publicized
Online ISSN
1745-1345
DOI
10.1587/transcom.E96.B.1716
Type of Manuscript
Special Section PAPER (Special Section on Internet Architectures, Protocols, and Management Methods that Enable Sustainable Development)
Category

Authors

Yuzo TAENAKA
  The University of Tokyo
Kazuya TSUKAMOTO
  Kyushu Institute of Technology
Shigeru KASHIHARA
  Nara Institute of Science and Technology
Suguru YAMAGUCHI
  Nara Institute of Science and Technology
Yuji OIE
  Kyushu Institute of Technology

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