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Recently, we proposed a multi-block frequency-domain equalization (MB-FDE) for single-carrier space-time block coded time-division duplex (SC-STBC TDD) transmission. In this paper, we propose an adaptive two-dimension (2D) multi-input multi-output (MIMO) channel estimation (CE) for SC-STBC TDD transmission in a high mobility environment. In the proposed adaptive 2D-MIMO-CE, the channel over consecutive...
This paper proposes a cost-aware opportunistic relaying scheme to minimize total cost in decoding and forwarding (DF) relay networks with power constraints. In the proposed scheme, a relay is selected such that it costs minimally among relays which correctly decode the signal from the source and have sufficient power to transmit the signal to the destination. We derive the outage probability and the...
Toward increased use of unmanned aircrafts (UA), researches and standardizations of the control communication system for UA using satellites in ITU-R and the like have been discussed recently. The National Institute of Information and Communications Technology (NICT) has been developing an on-board tracking antenna system for UA which realizes a communication link between UA and remote pilot through...
In this paper, a multi-stage LTCC bandpass filter with an good performance is proposed, which composes of six resonators. Two transmission zeros were realized by cross-coupling to achieve good stop-band attenuation. The filter is implemented based on the theory of the tapped combline filter, 3-D EM simulation technology, and design of experiment (DOE) method. It presents a small size, high frequency...
Demands for indoor-localization or indoornavigation are increasing in many fields such as a marketing, shopping related industries, and anticrime application. At present, many types of technologies of indoor-localization or indoor-navigation are proposed. Some examples are those that use ultrasonic waves, Wi-Fi, or IR-UWB. In this paper, we focus on IR-UWB technology because of its great potential...
Dynamic Spectrum Access provides novel solutions to improve spectral efficiency. Wireless Service Providers (WSPs) are allowed to transmit data over their exclusive licensed bands and multiple available unlicensed bands. The critical challenge is how to allocate power rationally to prevent severe interference between coexistent users. We formulate the problem as a Users Coexistence Game (UCG) and...
The security issue of wireless Implantable Medical Devices (IMD) is an emerging area of research. The unique challenge here is that an IMD should be accessed by doctors with no authorization for emergency treatments while it still has to be protected from adversaries. In this paper, we propose a novel ECG-based Secret Data Sharing (ESDS) scheme in order to protect the IMD data privacy against eavesdropping...
Cooperative multiple-input-single-output (CMISO) introduces cooperative nodes (Coops) to reduce the energy consumption of the cluster head (CH) in cluster-based M2M capillary networks. Although CMISO reduces energy consumption of CH, it introduces additional energy overhead to Coops, which contributes to a reduction of network lifetime. In this paper, we propose a joint CH and Coops selection (JCCS)...
Advances in wireless communication techniques enable pervasive and ubiquitous video applications. Among different factors concerned, energy efficiency is one of the most challenging issues in multimedia communication due to huge data traffic. Dynamic bursty interference sourcing from transmission of best effort service can make the Signal-to-Interference-plus-Noise-Ratio (SINR) of video traffic fluctuate...
In the research of green networks, considering the base station (BS) density from the perspective of energy efficiency is very meaningful for both network deployment and BS sleeping based power saving. In this paper, we optimize the BS density for energy efficiency in cellular networks by the stochastic geometry theory and optimize the user association matrix by the Quantum Particle Swarm Optimization...
A 40 GHz power amplifier (PA) driver for the remote antenna unit (RAU) transceiver of a mm-wave radio-over-fiber (RoF) system is presented in this paper. Mm-wave RoF is proposed as a complementary technology to fiber-to-the-home to minimize costs and to increase bandwidth. In order for RoF to be feasible, the cost of the RAU must be minimized through low-cost technology such as CMOS. The PA driver...
As traditional wireless cellular networks are facing a rapid growth of traffic demand, the future networks may consist of a large number of small cells which are densely deployed. However, a large number of small cell Base Stations (BSs) will consume a lot of energy, which is not conductive to improve the network Energy Efficiency (EE). The purpose of our research is to optimize the dense small cell...
With the maturity of 4G communication technologies and the popularity of smart devices, services over mobile devices are getting more and more popular, especially the mobile video services. In this paper, we propose a mobile video broadcast framework to provide each user with the most appropriate video quality according to his channel characteristic. To meet the demands of scalability and robustness,...
Demand has increased for better mobile phone and wireless local area network (LAN) access for passengers on-board aircraft. Meanwhile, based on the experience of Great East Japan Earthquake, it is essential for relief, restoration and reconstruction from the earthquake to grasp the situation after such damages by using aerial survey, and the broadband communication for transformation of those captured...
We derive capacity upper and lower bounds for a multi-user multiple-input multiple-output (MU-MIMO) system in a two dimensional line-of-sight environment where the central node is equipped with a uniform circular array and the remote nodes are distributed from the central node at an equal distance and equal angular separation. We first show that this channel can be represented by a circulant matrix...
Recently green communications in Heterogeneous Networks has attracted extensive attention. To improve Energy Efficiency (EE) in the premise of maintaining the throughput, we propose an energy-efficient time-power domain resources allocation algorithm. From the aspect of time domain, we propose an adaptive Almost Blank Subframe (ABS) configuration scheme to provide each sector a proper ABS ratio. From...
In this paper a distributed Q-learning based dynamic spectrum access (DSA) algorithm is applied to a cognitive cellular system designed for providing ultra high capacity density with only secondary access to an LTE channel. Large scale simulations of a stadium temporary event scenario show that the distributed Q-learning based DSA scheme provides robust quality of service (QoS) and extremely high...
This paper aims at constructing a reversed-routing tree (RRT) with self-reconfiguration for body sensor networks (BSN). There are two purposes of building the RRT: (i) to reduce packet collisions, a multi-hop tree structure is adopted to replace traditional single-hop star structure; (ii) to decrease packet loss ratio (PLR), the RRT selects the routes based on the link quality indicator (LQI). Moreover,...
An opportunistic relay selection scheme improving cooperative diversity is devised using the concept of a virtual SIMO-MISO antenna array. By incorporating multiple users as a virtual distributed antenna, not only helps combat fading but also provides significant advantage in terms of energy consumption. The proposed efficient multiple relay selection uses the concept of the distributed Alamouti scheme...
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