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60 GHz wireless communications is a key enabler for multi-Gigabit home networks capable of supporting next-generation applications and services. Adaptive beamforming techniques that are compatible with low-cost multiple antenna hardware configurations are important for full exploitation of the potential of the 60 GHz band. This paper overviews the mechanisms of multiple antenna processing as implemented...
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In the field of OFDM technology, it is known that the phase rotations and reverse of a block quaternary codeword give the same peak-to-mean-envelope-power-ratio (PMEPR) as that of the original word. In this paper, we show that there exist the third and fourth operations that also result in the same PMEPR.
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High rate and high quality of service as well as multi-technology connections are the key words for the future home networks. For this goal, we introduce a new convergence layer denoted inter-MAC, which provides a common infrastructure to the home network at layer 2. Among the inter-MAC functionalities, we focused our interest on the path selection mechanism. To improve quality of service, we define...
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Femtocells are a promising solution for the provision of high indoor coverage and capacity. Furthermore, OFDMA-based femtocells have proven to be highly versatile when dealing with cross-layer co-channel interference thanks to the allocation of frequency subchannels. However, concerns still exist related to the impact of the different access methods to femtocells in an overlayed network. Femtocells...
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One of the most recent trends in the area of B3G communications are reconfigurable, cognitive systems. Cognitive systems encompass self-management and self-optimization capabilities: awareness of user, device and context information, policies derivation, decision making, reconfiguration and learning. Mechanisms for perception and learning of user and context information are one of the most important...
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This paper introduces a network concept to handle heterogeneous and spectrum sharing (white space) type radio access networks, cognitive wireless cloud (CWC). This paper explains the overview, the system architecture, and the feasibility studies. As for the feasibility studies, network implementation and the development of new base station and terminal that suit for the CWC have done by using the...
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This paper details the current work status of the ETSI Reconfigurable Radio Systems (RRS) Technical Committee (TC) and gives an outlook on the future evolution. In particular, Software Defined Radio (SDR) related study results are presented with a focus on SDR architectures for Mobile Devices (MD), such as mobile phones, etc., as well as for Reconfigurable Base Stations (RBS). For MDs, a novel architecture...
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The media richness of the services available to the end consumer has had a constant increase rate of about 8% per year over the last century. Therefore, a major bottleneck risk, namely that the home network jeopardizes the quality of experience (QoE) of future services, urges to have an appropriate Gigabit solution available for home networks. In this paper we point out the challenges of future gigabit...
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In this paper we discuss on the cognitive management of wireless infrastructures that encompass Flexible Base Stations (FBSs) and Femtocells investigated by the Integrated Project E3 (End-to-End-Efficiency) funded within FP7. FBSs are equipped with Software Defined Radio (SDR) transceivers capable of operating the appropriate Radio Access Technologies (RATs) while Femtocells are capable of changing...
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This paper introduces the latest status of our undergoing project aiming at reliable communications by heterogeneous wireless networks. This project is one of the new Research and Development (R & D) projects in Japan to attain the efficient use of the precious and scarce radio spectrum resources. A test-bed facility has been developed and their features, specifications and some experimental results...
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This paper focuses on the application of cognitive radio technologies for sharing spectrum resources among multiple radio access networks (RANs) in a single network operator. As the RANs are assumed to be under the control by a single operating entity, the proposed architecture exploits intimate information exchange and admits tolerable interference among multiple RANs for achieving high efficiency...
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0.4-5.2 GHz broadband quadrature mixer (QMIX) and quadrature modulator (QMOD) using static frequency divider for multiband transceiver, and multimode transceiver IC having a low spurious local oscillator (LO) configuration using 2fLO switching circuit are described. Configurations of the fabricated RF-IC's and their measurement results for the multiband multimode transceiver are shown in this paper.
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To improve the spectrum utilization efficiency, cognitive radio (CR) has been proposed by allowing a cognitive radio network (CRN) to coexist with a licensed primary network. The security issues, although critical, have been less explored in the literature of CRN. In this paper, we consider a secure CRN in which a multi-antenna secondary user (SU) transmitter sends confidential information to a SU...
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A Femto base station (BS) is connected to operator's network using a residential DSL or cable broadband connection and provides service in the licensed spectrum. When a BS operates with time division duplex mode (TDD), synchronization of the transmission time at the BS is important to avoid inter-slot interference with adjacent BSs. Because femto BSs are generally located indoor, they may not receive...
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Future Home Access Networks (HANs) should operate at Gbit/s and provide data services that are as straightforward to use as an electrical outlet or any other utility. This is an extremely challenging goal, and an EU funded project 'Home Gigabit Access Networks' (OMEGA) aims to achieve this. In this project a significant part is to realize bi-directional Gigabit infrared (IR) optical wireless communications...
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Femtocell networks have the potential of significantly improving the capacity of next-generation cellular systems. However, interference to/from the macrocell network is a critical problem affecting the capacity. Co-channel operation with closed-subscriber group (CSG) access offers a large bandwidth to be shared by the users of the femtocell network; however, it also introduces significant interference...
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EARTH is a major new European research project starting in 2010 with 15 partners from 10 countries. Its main technical objective is to achieve a reduction of the overall energy consumption of mobile broadband networks by 50%. In contrast to previous efforts, EARTH regards both network aspects and individual radio components from a holistic point of view. Considering that the signal strength strongly...
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The expected massive adoption of home femto base stations will increase the overall power consumption, requiring eco-designed sleep modes. Whenever there are no user under the coverage of a home femto base station (at night for example), keeping it on can be seen as a waste of power, excessive interferences and lack of security. This paper proposes a method to switch-off the femto base station radio...
