A Combination of CS-CDMA and OFDM for Enhanced LTE on Downlink Channel

Bingli Jiao,Meng Ma,William C. Y. Lee 한국통신학회 2013 Journal of communications and networks Vol.15 No.1

For alleviating the low spectrum efficiency problem of orthogonal frequency division multiplexing (OFDM), due to the strong inter-cell-interference (ICI) at cell’s edge, we introduce comb-spectrum code division multiple access (CS-CDMA)into broadband OFDM system at downlink channel for enabling the use of entire spectrum for seamless coverage. In addition, we develop a new method, called orthogonal cell code (OCC) scheme,to assist CS-CDMA for nullifying the ICI from contiguous cells. In system operation, each of the conventional cells is divided into an outer cell and an inner cell, and a mobile station (MS) should access to the CS-CDMA when it is in the outer cell and access to OFDMwhen it is in the inner cell. This study investigates the spectrum efficiency of using CS-CDMA and makes a comparison with that of long term evolution (LTE) in the following cases; (1) under an assumption of perfect channel state information and (2) based on channel estimates at a MS station. The results show the great advantage of utilizing the proposed system.

A Combination of CS-CDMA and OFDM for Enhanced LTE on Downlink Channel

Jiao, Bingli,Ma, Meng,Lee, William C.Y. The Korea Institute of Information and Commucation 2013 Journal of communications and networks Vol.15 No.1

For alleviating the low spectrum efficiency problem of orthogonal frequency division multiplexing (OFDM), due to the strong inter-cell-interference (ICI) at cell's edge, we introduce comb-spectrum code division multiple access (CS-CDMA) into broadband OFDM system at downlink channel for enabling the use of entire spectrum for seamless coverage. In addition, we develop a new method, called orthogonal cell code (OCC) scheme, to assist CS-CDMA for nullifying the ICI from contiguous cells. In system operation, each of the conventional cells is divided into an outer cell and an inner cell, and a mobile station (MS) should access to the CS-CDMA when it is in the outer cell and access to OFDM when it is in the inner cell. This study investigates the spectrum efficiency of using CS-CDMA and makes a comparison with that of long term evolution (LTE) in the following cases; (1) under an assumption of perfect channel state information and (2) based on channel estimates at a MS station. The results show the great advantage of utilizing the proposed system.

Transmission Power Control for IEEE 802.15.6 Body Area Networks

Weidong Gao,Bingli Jiao,Guiliang Yang,Wei Hu,Jingwen Liu 한국전자통신연구원 2014 ETRI Journal Vol.36 No.2

Energy consumption is an important issue in body areanetworks (BANs). In this letter, we propose an energy efficienttransmission power control scheme for IEEE 802.15.6 BANs,which can improve energy efficiency by adaptively adjustingthe transmit power in an on-demand way to adapt to varyingchannel environments. Simulations are performed to evaluatethe performance, and it is shown that the proposed powercontrol scheme outperforms traditional ones in terms of energyefficiency without significant reliability degradation.

Morphological transformation of gold nanoparticles on graphene oxide: effects of capping ligands and surface interactions

Young-Seok Shon,Bingli Wa,Nisala Weerasuriya,Serena Low,Hanqing Pan 나노기술연구협의회 2019 Nano Convergence Vol.6 No.2

This article presents the influence of capping ligand and surface interaction types on the coarsening or reshaping behavior of surface-immobilized gold nanoparticles with different core size and shape. The morphological transformation of gold nanoparticles and nanorods on graphene oxide upon heating at temperatures ranging from 50 to 200 °C was investigated. The aggregation and coarsening behaviors of spherical nanoparticles on graphene oxide were slightly affected by the core size of nanoparticles (~ 1, 3, and 10 nm). The comparison of two different surface ligands revealed that glutathione ligands provide much better protection than cetyltrimethylammonium bromide ligands against the morphological transformation of nanoparticles. In addition, the evaluation of surface binding interactions indicated that the attachment of nanoparticles and nanorods onto graphene oxide with additional thiol functional groups could improve the immobilization of particles and therefore decelerate coarsening and reshaping of nanoparticle and nanorods.

Facile and highly effective synthesis of nitrogen-doped graphene quantum dots as a fluorescent sensing probe for Cu2+ detection

Bo Gao,Da Chen,Bingli Gu,Ting Wang,Zihao Wang,Feng xie,Yongsheng Yang,Qinglei Guo,Gang Wang 한국물리학회 2020 Current Applied Physics Vol.20 No.4

Nitrogen-doped graphene quantum dots (N-GQDs) with high blue fluorescence efficiency were synthesized by the hydrothermal method from p-Phenylenediamine and p-Coumaric acid. The N-GQDs possess several superiorities, most significantly in excellent solubility and superior photostability. Besides, the as-prepared N-GQDs exhibit a uniform size distribution with a diameter of about 3.8 ± 0.5 nm. After dispersing the N-GQDs in water, the formed aqueous solution still presents a stable and homogeneous phase even after 2 months at room temperature. The N-GQD dispersion was further utilized as sensing probes for the selective detection of copper ions (Cu2+), which is realized by the photoluminescence (PL) quenching of N-GQDs after adding Cu2+. The detection limit for Cu2+ was found to be 57 nM L−1, with superior selectivity in the presence of other commonly interfering metal ions. The presented results in this study provide a facile and high-efficiency method for synthesizing N-GQDs, with ultra-high detectivity and selectivity for Cu2+ detection, offering numerous opportunities for the development of biosensing, bioimaging, environment monitoring, and others.

Differently-charged graphene-based multilayer films by a layer-by-layer approach for oxygen gas barrier application

Liu, Hongyu,Wu, Jianping,Liu, Cuiyun,Pan, Bingli,Kim, Nam Hoon,Lee, Joong Hee Elsevier 2018 Composites Part B, Engineering Vol.155 No.-

<P><B>Abstract</B></P> <P>Polyelectrolyte-decorated graphene with positive and negative charges was prepared using graphene oxide as a precursor along with polyallylamine hydrochloride and poly (styrenesulfonate sodium) as surface modifiers, respectively. Driven by an electrostatic interaction, the as-obtained polyelectrolyte-decorated graphene sheets were self-assembled via a layer-by-layer method, producing graphene based composite multilayers. Field emission scanning electron microscopy (FE-SEM) images showed that the surface of composite film exhibited a mass of characteristic wrinkles of graphene. Interestingly, the cross-sectional FE-SEM of the film exhibited an unstratified structure, indicating a good dispersion of graphene sheets in the composite film. The results of oxygen gas permeability testing demonstrated that the resulting composite films exhibited excellent oxygen gas barrier properties. The oxygen gas transmission rate (OTR) of the composite film with 24 bilayers was as low as 1.2 cm<SUP>3</SUP> m<SUP>-2</SUP> d<SUP>-1</SUP>∙atm<SUP>−1</SUP>, exhibiting potential for use in packaging applications.</P>

Multi-Wavelength Clock Operation of NOLM for OTDM-WDM Conversion

Bing Li,K. J. Guan,P. D. Ye 한국통신학회 1997 OPTOELECTRONICS & COMMUNICATIONS CONFERENCE Vol.2 No.1

A Virtual MIMO Communication Strategy Based on Cooperative Groups for Wireless Sensor Networks

Bing Li,Guoqiang Zheng,Na Li,Jishun Li 보안공학연구지원센터 2015 International Journal of Future Generation Communi Vol.8 No.3

As we all know, virtual MIMO technology is an efficient way for energy saving in wireless sensor networks (WSNs). The present virtual MIMO communication strategies in WSNs depend on cluster heads collecting and forwarding source data, which causes big energy consumption. Aiming at this problem, we propose a new virtual-MIMO communication strategy based on cooperative group (CG) in this paper, called Group Collaboration MIMO (GCMIMO). GCMIMO clusters the WSN into several clusters. Each cluster is managed by two cluster heads, master cluster head (MCH) and vice cluster head (VCH). MCH divides the source nodes into several cooperative groups, every two nodes as a group. A CG can constitute a virtual dual-antenna transmitter for sending source data of both nodes directly. VCH and MCH are always seen as a CG, called master cooperative group (MCG), which can receive and forward the data from CGs of other clusters. Unlike the existing virtual MIMO communication strategy, GCMIMO doesn’t require the cluster heads collecting the data of the source nodes, which can reduce the times of source data transmission and improve the energy efficiency. In the simulation, we analyze the energy consumption in each communication phase of GCMIMO. The results indicate that GCMIMO can effectively decrease the energy consumption in data transmission and improve energy efficiency.

Regeneration of Wuxi's Industrial Heritage along the Grand Canal from a Cultural Landscape Perspective

Bing Li,Zeyun Zhan Korea Institute for Humanities and Social Sciences 2024 Journal of design futures (JDF) Vol.1 No.-

Background: In recent years, the academic community has been paying more and more attention to industrial heritage, and its conversation and regeneration have become a hot topic. Objective: This paper will discuss the protection and regeneration Wuxi from the perspective of cultural landscape. Methods: Through the perspective of cultural landscape, we find the problems and deficiencies of heritage protection and regeneration, and put forward targeted protection strategies based on this. Results: We should enhance the public's understanding of cultural landscape, promote the revitalization and regeneration of industrial heritage, and enhance cultural cognition and cultural confidence. Conclusions: Looking at the work of architectural heritage conservation and renewal from the perspective of cultural landscape helps to fully explore the cultural connotation behind the heritage and ensure that the work of heritage conservation and renewal is carried out accurately, efficiently and purposefully.

Determination of inclination of strut and shear strength using variable angle truss model for shear-critical RC beams

Bing Li,Cao Thanh Ngoc Tran 국제구조공학회 2012 Structural Engineering and Mechanics, An Int'l Jou Vol.41 No.4

This paper attempts to determine the inclination of the compression strut within variable angle truss models for RC beams loaded in shear-flexure through a proposed semi-analytical approach. A truss unit is used to analyze a reinforced concrete beam, by the principle of virtual work under the truss analogy. The inclination of the compression strut is then theoretically derived. The concrete contribution is addressed by utilizing the compatibility condition within each truss unit. Comparisons are made between the predicted and published experimental results of the seventy one RC beams with respect to the shear strength and the inclined angle of the compression strut at this state to investigate the adequacy of the proposed semi-analytical approach.