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Takeshi KAKEHI Ryoichi SHINKUMA Tutomu MURASE Gen MOTOYOSHI Kyoko YAMORI Tatsuro TAKAHASHI
The market growths of smart-phones and thin clients have been significantly increasing communication traffic in mobile networks. To handle the increased traffic, network operators should consider how to leverage distributed wireless resources such as distributed spots of wireless local access networks. In this paper, we consider the system where multiple moving users share distributed wireless access points on their traveling routes between their start and goal points and formulate as an optimization problem. Then, we come up with three algorithms as a solution for the problem. The key idea here is 'longcut route instruction', in which users are instructed to choose a traveling route where less congested access points are available; even if the moving distance increases, the throughput for users in the system would improve. In this paper, we define the gain function. Moreover, we analyze the basic characteristics of the system using as a simple model as possible.
Yin WAN Kosuke SANADA Nobuyoshi KOMURO Gen MOTOYOSHI Norio YAMAGAKI Shigeo SHIODA Shiro SAKATA Tutomu MURASE Hiroo SEKIYA
This paper presents an analytical model for network throughput of WLANs, taking into account heterogeneous conditions, namely network nodes transmit different length frames with various offered load individually. The airtime concept, which is often used in multi-hop network analyses, is firstly applied for WLAN analysis. The proposed analytical model can cover the situation that there are saturation and non-saturation nodes in the same network simultaneously, which is the first success in the WLAN analyses. This paper shows the network throughput characteristics of four scenarios. Scenario 1 considers the saturation throughputs for the case that one or two length frames are transmitted at the identical offered load. Scenarios 2 and 3 are prepared for investigating the cases that all network nodes transmit different length frames at the identical offered load and identical length frames at the different offered loads, respectively. The heterogeneous conditions for not only frame length but also offered load are investigated in Scenario 4.
Gen MOTOYOSHI Kenji LEIBNITZ Masayuki MURATA
Several task forces have been working on how to design the future Internet in a clean slate manner and mobility management is one of the key issues to be considered. However, mobility management in the future Internet is still being designed in an “all-in-one” way where all management functions are tightly kept at a single location and this results in cost inefficiency that can be an obstruction to constructing flexible systems. In this paper, we propose a new function-distributed mobility management architecture that can enable more flexible future Internet construction. Furthermore, we show the effectiveness of our proposed system via a cost analysis and computer simulation with a random walk mobility model.
Yuichi SUDO Toshimitsu MASUZAWA Gen MOTOYOSHI Tutomu MURASE
Users of wireless mobile devices need Internet access not only when they stay at home or office, but also when they travel. It may be desirable for such users to select a "longcut route" from their current location to his/her destination that has longer travel time than the shortest route, but provides a better mobile wireless environment. In this paper, we formulate the above situation as the optimization problem of “optimal longcut route selection”, which requires us to find the best route concerning the wireless environment subject to a travel time constraint. For this new problem, we show NP-hardness, propose two pseudo-polynomial time algorithms, and experimental evaluation of the algorithms.