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Caching popular contents at mobile devices, assisted by device-to-device (D2D) communications, is considered as a promising technique for mobile content delivery. It can effectively reduce backhaul traffic and service cost, as well as improving the spectrum efficiency. However, due to the selfishness of mobile users, incentive mechanisms will be needed to motivate device caching. In this paper, we...
Localization of sensor nodes is important for wireless sensor networks (WSNs) especially for underwater WSNs (UWSNs). Among the existing UWSN localization approaches, reverse localization scheme (RLS) is an event-driven method suitable for underwater surveillance. RLS adopts the strongest arrival or the first arrival as the direct path, which is however not accurate enough due to the severe multipath...
Caching at mobile devices, accompanied by device-to-device (D2D) communications, is one promising technique to accommodate the exponentially increasing mobile data traffic. While most previous works ignored user mobility, there are some recent works taking it into account. However, the duration of user contact times has been ignored, making it difficult to explicitly characterize the effect of mobility...
We consider nonlinear transceiver design for downlink multiuser multi-antenna secure communications with an external multi-antenna eavesdropper. The multi-antenna transmitter simultaneously transmits confidential-message-bearing signals and artificial noise (AN) using nonlinear Tomlinson Harashima precoding based on the limited channel state information feedback. For the proposed nonlinear secure...
Current large-scale computing services, such as online social networking and web searching, make the wired links in the data centers with an Ethernet infrastructure oversubscribed. Therefore, researchers consider to augment the data centers with wireless communication, called a hybrid data center network (HDCN), to improve the communication flexibility and network capacity. In this paper, we investigate...
With the growing demand on wireless multimedia services and omnipresent access, the energy consumption rises sharply. Consequently, energy efficiency (EE) has become an essential problem in the design of green radio. In order to reduce computational complexity, we separate the resource allocation into two steps: subcarrier allocation and power allocation. After subcarrier allocation, we adopt biogeography-based...
In this paper, a multiuser wireless powered communication network is considered where all users harvest energy from power beacons by wireless power transfer to support their uplink information transmission. A frequency-division duplex transmission scheme is adopted, where downlink power transfer and uplink information transmission are separated in different frequency bands. Compared with the time-division...
The path loss model describing the power-law dependency on distance plus a log-normally distributed shadowing attenuation, is a staple of link budgets and system simulations. Determination of the parameters of this model is usually done from measurements and ray tracing. We show that the typical least-square fitting to those data points is inherently biased to give the best fitting to the link distances...
We have developed a wireless system suitable for acquiring gastric slow wave activities and delivering electrical pulses to the stomach. The system is composed of a physically miniaturized front-end that can record slow waves from 3 channels and transmit the data to a back-end connected to a computer. A custom-made graphical user interface can display the slow waves in real-time and store them for...
In this paper, we focus on a problem of joint subcarrier and rate allocation for an orthogonal frequency division multiple access (OFDMA) full-duplex (FD) system. The goal is to maximize the system's successful transmission rate (referred as goodput) subject to power constraints at the base station (BS) and uplink users alone with subcarrier constraints. Imperfect channel state information (CSI) at...
Magnetic induction (MI) is a promising technique for communications in the very harsh propagation conditions like underground or underwater, etc. In this paper we investigate the connectivity issue of MI ad hoc networks deployed in a three-dimensional space. The transmitting distance of MI covers a quasi- ellipsoid space other than a standard sphere space in a traditional wireless propagation case...
There has been an increasing interest in Full- Dimension (FD) MIMO, i.e., exploiting the elevation domain (in addition to the azimuth domain) for increasing the capacity of multi-antenna systems. A first prerequisite for designing FD MIMO is an understanding of the elevation characteristics of wireless propagation channels, in particular elevation at the base station. This paper utilizes a state-of-art...
In wireless ad hoc and sensor networks, localization is a fundamental service to provide location information for those nodes without GPS units. In this paper, we use a simple yet effective proximity measure, called Regulated Neighborhood Distance (RND), to measure the closeness between two neighboring nodes based on their neighbors' numbers. Furthermore, we propose a RND-based localization algorithm,...
Adaptive modulation technique has been widely used in wireless communication systems and channel prediction plays an important role in adaptive modulation technique. Minimax probability machine shows good performance in classification and prediction by controlling the generalization error boundary and trying to make it lowest. In this paper, we introduce a nonlinear prediction algorithm of fast fading...
Currently embedded remote monitoring technology step into a rapidly developing period. With the advancement of related technology, low cost remote monitoring system which is web-based, powerful and reliable at the same time will become the mainstream. Under this background, this paper presents a lightweight embedded remote monitoring system. The owerall system established a LAN using zensys's Z-WAVE...
In this paper, the technology of ZigBee based on wireless sensor network was adopted to carry out the real-time oxyhemoglobin saturation monitoring. C8051F340 was used to control UZ2400 as MCU(Micro Control Unit). Electricity was consumed less than 2mA when it worked and electricity was consumed less than 1μA when it slept. This system can prolong the life time of battery effectively. And the system...
Delay is an important metric in Wireless-Optical Broadband Access Network (WOBAN). We introduce external buffer and design Delay-Differentiated Routing Algorithm (DDRA) for WOBAN. We show that delay performance of WOBAN can be improved by DDRA.
Differential evolution has emerged as one of the fast, robust, and efficient global optimization approach of current interest. In this paper, an application of differential evolution to the location management problem in mobile computing is described. To improve the convergence rate and the quality of solutions of the differential evolution algorithm, an effective population initialization strategy...
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