Browsing by Author "Tanaka, Y."

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    Comparison of Interference Reduction Schemes by Femto Base Stations to Macro Cell Users
    (Institute of Electronics, Information and Communication Engineers (IEICE), 2010) Tanabe, Y.; Afolabi, A. S.; Ohta, C.; Tamaki, H.; Tanaka, Y.; Yamamoto, T.; Okada, Y.
    In 3GPP TR25.820, three kinds of approaches, access control, bandwidth control, and power control, to reduce interference from femtocell to macrocell are examined. Further, five types of configurations as combinations of these approaches are also discussed. The relative effectiveness among these configurations are, however, not clear since they are not compared in the same scenario enough. Therefore, at the beginning in this paper, under the simple scenario where one femto-cell exists in one macro-cell, we compare Shannon capacities of the following three configurations: 1) Open Access, Co-channel, and Fixed Power, 2) CSG (Closed Subscriber Group), Dedicated Channel, and Fixed Power, 3) CSG, Co-channel, and Adaptive Transmission Power. We also investigate conditions that transmission power control is effective.
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    Fair Partitioning of the Downlink Resources of an OFDMA-based Multi-User Multi-Tier Cellular Network Using Fractional Frequency Reuse
    (Maruzen Co., Ltd/Maruzen Kabushikikaisha, 2012) Afolabi, A. S.; Munkhbat, E.; Takaki, Y.; Ohta, C.; Tamaki, H.; Tanaka, Y.; Yamamoto, T.; Okada, Y.
    Orthogonal Frequency Division Multiple Access (OFDMA) is a leading air interface candidate for future generation cellular networks. However, if deployed in a multi-user multi-tier cellular system, it is important to fairly share radio resources such as transmission power and sub-carriers among co-tier and cross-tier users. This paper focuses on a mathematical formulation of cell inner-zone radio resource partitioning variables and considers the case of an FFR-based macrocell underlaid with femtocell. By applying an exhaustive search procedure on the developed formulation, we determine the optimal radio resource partitioning parameter values from the perspectives of macrocell user fairness and femtocell throughput maximization.