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Orthogonal frequency division multiplexing access (OFDMA) inherently suffers from large spectral sidelobes, which will lead to interference between users and can not be ignored. In this paper, in order to suppress spectral sidelobes, we propose a novel windowing scheme. The derivation of the optimum window function is based on the solution of an optimization problem. It aims to minimize in-band-out-of-subband...
Data aggregation is a significant issue for marine wireless sensor networks. However, marine sensors are always deployed far away from the security monitoring. Thus, the secure data aggregation for marine sensor networks emerges and attracts the researchers and engineers. Multi-signature enables the data aggregation with a single signature to authenticate the message under different signers. However,...
In this paper, channel measurements for the 2.6 GHz band in railway environments are presented. The measurements have been carried out in the subway of Madrid in different environments (tunnel, station and open air scenarios). An intra-consist link for a future wireless Train Control and Management System (TCMS) has been measured for two types of trains, a continuous train and a non-continuous train...
Nowadays technology advances of wireless networking and mobile devices have made anytime anywhere data access become readily available. This also enables crowdsourced content capturing and sharing, especially for such multimedia data as video. One example is Twitter's Vine, which mainly target mobile devices, allowing users to create ultra-short video clips and instantly share with their followers...
In this paper, we consider the problem of neighbor discover in three-dimensional wireless mobile ad hoc networks with directional antennas. A directional neighbor discovery algorithm named Limited Random Algorithm(LRA) is proposed in the paper. The difference between LRA and previous researches that assume no prior knowledge of neighbors, is that LRA takes advantage of the approximate location information...
This paper investigates the resource optimization problem for the multiple-input multiple-output (MIMO) cognitive radio (CR) networks. Different from the conventional works, a novel optimization metric, namely the bandwidth-power product (BPP), is used to achieve the optimal spectrum sharing. We apply the direct-channel singular value decomposition (DC-SVD) method to design the optimal source precoding...
By summarizing extensive literature, this paper presents a panorama of the path loss exponent and shadow fading distribution in the main rail traffic scenarios. This panorama is very useful to gain a comprehensive understanding of the propagation. Moreover, with the aid of the table provided in this paper, designers can easily realize a fast network planning for a long railway with various scenarios,...
This paper investigates the Tomlinson-Harashima precoding (THP) design for secure communications in broadcast multiple-input multiple-output (MIMO) systems in the presence of a passive eavesdropper. We focus on optimizing the nonlinear transceiver to guarantee a certain Quality-of-Service (QoS) level for the intended receiver in terms of mean-squared-error (MSE). The scheme allocates the transmit...
In this paper, new fountain codes named LT-LR-DRS (Luby Transfer with Loss Rate and Decreasing Ripple Size) codes are proposed for wireless relay communications. The transmission is divided into two phases: at first phase, all original symbols are transmitted and some original symbols are lost during transmission; encoded symbols generated by LT-LR-DRS codes are transmitted at second phase to recover...
This paper proposes multi-mode transferred power amplifier design. Several discrete frequency points, along with their second and third harmonics are controlled simultaneously by a special output matching network in PA. It allows the PA to transfer its mode to different typical high efficiency classes in these deliberately selected frequencies, which are referred to LTE and 3G systems. The measurement...
Flow-field Fitting Method is a brand-new physical detection technology which is put forward by Academician He Jisan of Central South University.This paper gives a detailed introduction to Foundation Pit Leakage Detector based on Flow-field Fitting Method,which mainly includes transmitter,receiver and host computer control software. The transmitter transmits 3–12V adjustable amplitude bipolar square...
Area spectral efficiency (ASE) was introduced as a metric to quantify the spectral efficiency of cellular systems. Unlike other performance metrics, ASE takes into account the spatial property of cellular wireless system. In this paper, we generalize the ASE metric for arbitrary wireless transmission. Specifically, we introduce the concept of affected area, based on which we evaluate the spectral...
Based on the high level swimming teams of Tongji University This essay introduces a specific training information system used in swimming which was built by the skill of electrommunication, network communication and database technology. In this system, using the ZigBee transmission technology, a wireless real-time timer technique was adopted and communication master station was used. As a result,...
This paper presents the design of a balanced power amplifier at 6.15GHz for wireless communication systems in the higher frequency band. Two final stage amplifiers are connected in parallel through two branch line hybrid couplers, to obtain good input and output VSWR performance. The digital predistortion technique is used to further improve the linearity. The measured results show that the developed...
In this paper, we investigate the downlink spectral efficiency of infrastructure relay-enhanced cellular systems. In particular, we use the average achieved spectral efficiency at an arbitrary mobile receiver in presence of co-channel interference, termed as cell spectral efficiency (CSE), to quantify the benefit of relay transmission in terms of lower co-channel interference power. We derive the...
This paper investigates the area spectral efficiency (ASE) of infrastructure-relay enhanced single-cell wireless system. ASE serves as an attractive alternative performance metric by taking into account of the relatively smaller spatial footprint of relay transmission steps. We extend the notion of ASE into relay transmission scenario and derive its accurate mathematical expressions as a function...
This paper introduces a novel paradigm for designing the physical and medium access control (MAC) layers of mobile ad hoc or peer-to-peer networks formed by half-duplex radios. A node equipped with such a radio cannot simultaneously transmit and receive useful signals at the same frequency. Unlike in conventional designs, where a node's transmission frames are scheduled away from its reception, each...
In order to guarantee the effective control to the appliances and ensure the safety of living environment, a control system for smart home has been designed. Based on the GSM network service and wireless communication, the system is developed with the MCU AVR mega 16 as the core. It can be divided into two working patterns: the long-distance pattern and the short- range pattern. Experiments have proved...
In the further advancements for the third generation (3G) long-term evolution (LTE) system, i.e. the LTE-Advanced system, carrier aggregation (CA) is applied to support wide system bandwidth and ensure backward compatibility. In this paper, two traffic load balance methods are proposed to improve the performance of the independent carrier scheduling (ICS) scheme in CA based LTE-Advanced system with...
Spectrum sensing is one of the critical tasks of the cognitive radio networks. In order to solve the hidden terminal problem, cooperative spectrum sensing has been studied to improve the spectrum sensing performance. In this paper, we study the performance of cooperative spectrum sensing in both AWGN channels and Rayleigh fading channels. In particular, the paper reports results obtained through the...
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