Jiang Liu

• Professor
• Waseda University

With the continuous improvement of the world’s economic development level, the traffic pressure on the road networks of major cities around the globe has been increasing. Influenced by multiple factors, the traffic pressure on urban road networks is not balanced in different directions and at different times. We evaluated and analyzed the efficienc...

In our paper, we proposed an Energy Borrowing (EB) transmission scheme which is used to conserve the battery life of user equipment (UE), such as a mobile phone. EB is based on device-to-device (D2D) communication and cellular networks, particularly, on out-band D2D (Wi-Fi Direct, IEEE 802.11) and 5G networks. Since D2D offers higher energy efficie...

This paper proposes a Hybrid Access Scheme (HAS) aiming to convert a future robot’s backend communication system by a finite number of sensors instead of using a lot of wires. To replace this communication, the HAS needs to assure higher reliability within stringent low latency packet transmission. In this paper, the HAS utilizes the packet diversi...

Cellular systems are facing the ever-increasing demand for vehicular communication aimed at applications such as advanced driving assistance and ultimately fully autonomous driving. Cellular Vehicle to Anything (C-V2X) has become more applicable with the release of the first sets of 5G (5 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xl...

Ultra-Reliable Low-Latency Communication (URLLC) is challenging due to its extremely higher reliability requirement with stringent short latency packet transmission. In order to overcome this reliability and latency bound, a communication access scheme needs to assure almost error-free and high speed packet transmission. In this paper, a new multip...

In this paper, a novel triple-band antenna with reflector surface which has the property of both artificial magnetic conductor (AMC) surface and perfect electric conductor (PEC) for WLAN and Sub-6G 5G applications is proposed. The presented antenna is composed of two parts: the AMC surface and the microstrip-fed printed dipole. Baluns are used to e...

Nowadays, within the concept of Internet of Things (IoT), smart homes, smart factory, intelligent transportation among others are infrastructure systems that connect our world to the Internet. However, wireless communications technology are considerably constrained by complicated structures, and lossy media in complex environments. Fundamental limi...

The diverse architectural evolution and intensive data explosion in the forthcoming 5G will have severe impacts on providing seamless and robust mobility management. In this paper, P-persistent energy-aware handover (HO) decision strategies with mobility robustness are proposed both for intra-handover cases while a femto user equipment (FUE) roams...

This article proposes a novel chunk-based caching scheme known as the Progressive Popularity-Aware Caching Scheme (PPCS) to improve content availability and eliminate the cache redundancy issue of Information-Centric Networking (ICN). Particularly, the proposal considers both entire-object caching and partial-progressive caching for popular and non...

This paper studies a noninvasive method to measure glucose level based on ultrasonic transducer and near infrared spectrometer. A series pair data of ultrasonic transducer from human finger, palm, wrist and arm are collected six times a day, and 16 spectral data of NIR spectrometer (reflection) from finger are collected by an OGTT experiment. The c...

This paper studies the emerging wireless energy harvesting algorithm dedicated for machine type communication (MTC) in a typical cellular network where one transmitter (e.g. the base station, a hybrid access point) with constant power supply communicates with a set of users (e.g. wearable devices, sensors). In the downlink direction, the informatio...

This paper studies the emerging wireless power transfer for the Internet-of-Things (IoT) network where one hybrid access point (H-AP) with constant power supply communicates with a set of IoT devices. This H-AP is assumed to work in a full-duplex mode, which transmits/receives signals to/from these IoT devices simultaneously during the whole frame....

By 2020, 5G era will be commercially available. The smart city construction will also make great progress. Compared to current situation, more than thousand times of devices will connect to the cellular networks. For the operators, in order to analyze overall network performance, it is a key factor to estimate the user equipment (UE) radio frequenc...

Recently, the 3rd Generation Partnership Project (3GPP) proposes to extend the Long Term Evolution Advanced (LTE-A) to the unlicensed spectrum, named Long Term Evolution Unlicensed (LTE-U), which enables LTE to operate in both the licensed band and the unlicensed band. In this paper, we consider how to make LTE-U get even higher throughput in the h...

Using conventional approaches to estimating arterial oxygen saturation (i.e., SpO2) for individuals, it was impossible to measure unless the given sensor of the pulse oximeter was attached to the finger. In this study, we attempted to realize successful SpO2 measurements using non-contact space measurements and succeeded in our experiments. Our wor...

The ongoing 5G cellular networks are expected to meet the demands posed by the energy and radio resource crises, especially exploiting flexible management for the traffic in idle zone. In this paper, two energy optimizing solutions are proposed for macro-tier with the tradeoff consideration regarding spectrum efficiency (SE) and Quality of Service...

This paper studies the emerging wireless power transfer for machine type communication (MTC) network where one hybrid access point (AP) with constant power supply communicates with a set of users (i.e., wearable devices, sensors) without power supply. The information and energy are transferred simultaneously in downlink direction. For MTC networks,...

This paper proposes a novel data acquisition frame- work in sensor networks using an unmanned aerial vehicle (UAV) with the goal of increasing the efficiency of the data gathering efforts. To maximize the system throughput, we introduce a priority-based frame selection scheme to suppress the number of redundant data transmissions between sensor nod...

Satellite clusters have been satisfactorily implemented in a number of applications, such as positioning and sensor networks, with the purpose of improving communication system capabilities. However, because the use of clusters requires good management of the resources, those solutions imply new challenges for communication systems. This paper focu...

In this paper, we propose an effective data gathering protocol in an air-to-ground communication network employing priority-based contention window adjustment scheme. The proposed protocol adopts a conventional CSMA/CA. An unmanned aerial vehicle is used as a relay sink to collect data from a ground wireless sensor network. In our scheme, we divide...

Based on the use of multi-beams, high throughput satellites (HTSs) provide high data rates to a large number of users. In this context, the distribution of frequency resources among multi-beams plays an important role. This is because unsuitable distributions might cause the wastage or the starvation of frequencies and bring about low throughput ra...

In this paper, we propose an optical wireless communication service for indoor environment. To seamlessly cover the target area and keep the received signal power strength at an acceptable level, we send the signal from multiple diffused optical emitters and achieve possible transmit diversity. With the proposed diversity scheme, the effective cove...

This paper presents an optical wireless identification (OWID) scheme utilizing high-energy harvesting thinfilm embedded onto the corner cube retroreflector (CCR). We apply optical wireless communication (OWC) for transmitting information. The thinfilm is used as a rechargeable battery that absorbs the power when the incident light beam goes through...

This paper proposes a hybrid communication system for Intelligent Transportation System (ITS) utilizing visible light and radio communications for position-based services. The directionality of light communication is used to distribute position-based keys to vehicles such that they can extract information related only to their desired lanes. The ex...

We present a study on evaluating the effects of multipath dispersion on indoor optical code division multiple access (CDMA) systems over optical wireless communication. The indoor propagation channel model which takes multiple reflecting surfaces into account is addressed. Theoretical analysis of the pulse response of direct light and reflected lig...

This paper presents a free space visible light communication (VLC) system using an image sensor as a receiver to acquire position related timely information. Since the atmospheric turbulence affects the communication quality, the analysis of atmospheric turbulence is very important for designing a practical communication system. In this paper, the...

Developments in outdoor free space optical (FSO) communication between buildings using rooftopmounted units are limited by Point-to-Point wireless links. We propose a space and time division multiple access scheme to perform Point-to-Multi-Point communication employing reflectors. A single reflector controlled by a stepping motor and an array of fi...

This paper studies an Orthogonal Frequency Division Multiplexing (OFDM) based wireless services employing Radio over Optical Wireless (RoOW) to get a high performance transmission while eliminating the drawback of possible radio wave interference to electro-medical apparatus in indoor communication system. An optical Intensity-modulated Direct-dete...

This paper presents hybrid RFID – OWC with an adaptive priority transmission scheme. In this model, we apply optical wireless communication (OWC) for transmitting confidential information to a radio frequency identification (RFID) reader. Since OWC provides high security, this improves the security of our system. The priority of information is assi...

We propose a position-based diversity transmission scheme for indoor optical wireless communication. In our scheme, the I (in-phase) and Q (Quadrature) signal of QPSK (quaternary phase-shift keying) modulation are transmitted separately to obtain a secure position-based transmission. We analyze probability of error with different mode numbers of th...

In this paper, we present a novel relay system in which a radio frequency (RF) signal is relayed over optical media to provide wireless communications in RF sensitive areas. We refer to this as RF over Optical (RFoO). Different from conventional relay systems, we adopt RF band phase shift beamforming to adjust the initial phases of the RF signal be...

The rapid developments of the image sensor technology have made them an important tool in different areas. Many applications utilizing image sensors were proposed. In recent years, there is a tendency to utilize light-emitting diodes (LED) as a light source replacing normal lamps due to its obvious advantages over incandescent light sources, which...

This is a study on the effect of reflected light on optical code-division multiple-access (CDMA) system over indoor optical wireless communication (OWC). The indoor propagation channel model which takes multiple reflecting surfaces into account was addressed. Theoretical analysis of the pulse response of direct light and reflected light is given. B...

This paper presents a novel position based access scheme for indoor optical wireless communication systems. In this scheme, we apply the Intensity Modulation-Direct Detection (IM/DD) with Quadrature Phase Shift Keying (QPSK) modulation. The I (in-phase) and Q (Quadrature) signal are transmitted separately in Additive White Gaussian Noise (AWGN) cha...

This paper presents hybrid RFID with optical wireless communication. In this model, we apply optical wireless communication for transmitting the confidential information to RFID reader to improve security of the system. The energy harvesting of RFID is used for driving Liquid Crystal Shutter to modulate reflecting optical signal by Corner Cube Retr...

We present a relay system which uses RF over Optical (RFoO) to provide wireless communications in RF sensitive areas. Different from other relay systems, we adopt RF band phase shift beamforming to adjust phases of RF signal before modulating it into an optical band. Benefitting from it, the energy of transmitted signal is able to be concentrated i...

This paper presents an optical intensity-modulated direct-detection (IM/DD) based relay scheme for indoor optical wireless communication system. Multiple distributed optical relay links are set up between relay stations (RS) and mobile terminals (MT) to create multiple safe signal propagation links for wireless communication so that at least one li...

This paper presents a wireless relay scheme for indoor healthcare communication system, in which an optical relay link, instead of a traditional radio frequency (RF) relay link, is established between the relay station (RS) and the mobile terminal (MT). To simplify the structures of RS and the additional optical parts that shall be installed in the...

The paper describes a low complexity tree-structure based user scheduling algorithm in a MLD-based multi-user multiple-input multiple-output (MIMO) wireless systems. An M-branch selection algorithm, which selects M most-possible best branches at each step, is proposed to maximize the whole system sum-rate capacity. To make this work more feasible,...

There has been many developments in long distance optical wireless communication between buildings using rooftop- mounted units over Point-to-Point wireless links. We propose an Angle Division/Time Division Multiple Access scheme to perform Point-to-Multi-Point communication employing reflectors. A single reflector controlled by a stepping motor an...