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Routing Protocol with Optimal Location of Aggregation Point in Wireless Sensor Networks

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The Journal of China Universities of Posts and Telecommunications 2006年第1期13卷 1-5页

作者： LIU Yue-yang ji hong YUE Guang-xin School of Telecommunications Engineering Beijing University of Posts and Telecommunications Beijing 100876 P.R. China

A wireless sensor network is typically composed of hundreds, even thousands of tiny sensors used to monitor physical phenomena. As data collected by the sensors are often redundant, data aggregation is important for conserving energy. In this paper , we present a new routing protocol with optimal data aggregation. This routing protocol has good performance due to its optimal selection of aggregation point locations. This paper details the optimal selection of aggregation point locations.

关键词： wireless sensor networks routing protocol data aggregation

Spectrum efficiency sub-carrier and energy efficiency power allocation for downlink multi-user CoMP in multi-cell system

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The Journal of China Universities of Posts and Telecommunications 2014年第3期21卷 29-34页

作者： LIU Kai LI Yi ji hong WU Xu-guang School of Telecommunication Engineering Beijing University of Posts and Telecommunications

Coordinated multi-point transmission/reception （CoMP） was proposed currently as an effective technology to improve cell-edge throughput in next-generation wireless systems. Most of the existing work discussed clustering methods mostly to maximize the edge user throughput while neglecting the problem of energy efficiency, such as those algorithm clustering base stations （BSs） of better channel condition and BSs of worse channel condition together. In addition, BSs usually increase the transmit power to achieve higher throughput without any considering of interference caused to other users, that may result in energy waste. The authors focus on the throughput maximizing problem while fully considering energy saving problem in CoMP systems. A coefficient is defined to describe the fitness of clusters. Then a sub-carrier allocation algorithm with clustering method is put forward for CoMP downlink, which can save the transmit power of BS and increase the throughput. Furthermore a power allocation scheme is proposed based on non-cooperation game; in which the transmit power is decreased by BSs generally to reach the Nash equation （NE）. Simulation shows that the proposed sub-carrier allocation scheme and power allocation algorithm are better than the existing ones on users＇ throughput while consumes much less energy.

关键词： CoMP energy saving game theory power allocation sub-carrier allocation

Multi-user selection based on particle swarm optimization and power control scheme in the uplink CoMP-MU-MIMO system

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The Journal of China Universities of Posts and Telecommunications 2013年第5期20卷 79-84页

作者： LIU jian LI Xi ji hong ZHANG Xiao-liang School of Telecommunication Engineering Beijing University of Posts and Telecommunications

Orthogonal frequency division multiplexing （OFDM） which has been adopted in the long-term evolution （LTE） system can improve the system capacity obviously. However, it also brings about severe inter-cell interference （ICI） for cell-edge users （CEUs）. To tackle this problem, multi-user selection and power control （MuS-PC） is proposed as an efficient scheme in uplink coordinated multi-point multi-user multi-input multi-output （CoMP-MU-MIMO） transmission/reception. This paper jointly considers user＇s signal to interference plus noise ratio （S1NR） and proportional fairness （PF） to maximize the total channel capacity in multi-user selection by formulating a penalty function. To simplify the penalty function＇s computation, particle swarm optimization （PSO） algorithm is introduced. In addition, power control is adopted to maximize overall energy efficiency. Simulation results demonstrate that the MuS-PC scheme can not only obtain the optimal total channel capacity while guarantee each user＇s quality of service （QoS） and PF, but also largely reduce computational complexity and improve energy efficiency. As a result, the poor communication quality of CEUs can be enhanced.

关键词： CoMP-MU-MIMO system PSO algorithm penalty ftmction multi-user selection power control zero forcing (ZF) equalization

Dynamic control approaches of spectrum sensing in multi-band cognitive radio networks

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The Journal of China Universities of Posts and Telecommunications 2010年第5期17卷 20-25页

作者： AN Chun-yan ji hong SI Peng-bo MAO Xu College of Information and Communication Engineering Beijing University of Posts and Telecommunications Beijing 100876 China College of Electronics Information and Control Engineering Beijing University of Technology Beijing 100022 China

In this paper,the dynamic control approaches for spectrum sensing are proposed,based on the theory that prediction is synonymous with data compression in computational ***,a spectrum sensing sequence prediction scheme is proposed to reduce the spectrum sensing time and improve the throughput of secondary *** use Ziv-Lempel data compression algorithm to design the prediction scheme,where spectrum band usage history is *** addition,an iterative algorithm to find out the optimal number of spectrum bands allowed to sense is proposed,with the aim of maximizing the expected net reward of each secondary user in each time ***,extensive simulation results are shown to demonstrate the effectiveness of the proposed dynamic control approaches of spectrum sensing.

关键词： spectrum sensing sequence optimal number of spectrum bands cognitive radio networks Ziv-Lempel algorithm

Buffer-aware resource scheduling scheme for LTE-A uplink relay-assisted network

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The Journal of China Universities of Posts and Telecommunications 2013年第6期20卷 30-35页

作者： TANG Yi-wen LI Xi ji hong LIU jian School of Telecommunication Engineering Beijing University of Posts and Telecommunications

Due to the constraint of single carrier frequency division multiple access （SC-FDMA） adopted in long term evolution （LTE） uplink, subcarriers allocated to single user equipment （UE） must be contiguous. This contiguous allocation constraint limits resource allocation flexibility and makes the resource scheduling problem more complex. Most of the existing work cannot well meet UE＇s quality of service （QoS） requirement, because they just try to improve system performance mainly based on channel condition or buffer size. This paper proposes a novel resource scheduling scheme considering channel condition, buffer size and packet delay when allocating frequency resource. Firstly, optimization function is formulated, which aims to minimize sum of weight for bits still left in UE buffer after each scheduling slot. QoS is the main concern factor here. Then, to get packet delay information, this paper proposes a delay estimation algorithm. Relay node （RN） is introduced to improve overall channel condition. Specific RN selection strategy is also depicted in the scheme. Most important of all, a creative negotiation mechanism is included in the subcarrier allocation process. It can improve the overall system throughput performance in guarantee of user＇s QoS requirement. Simulation results demonstrate that the scheme can greatly enhance system performance like delay, throughput and jitter.

关键词： SC-FDMA relay scheduling LTE-A MBDF BDF-PF

Traffic-based queue-aware scheduling for 3GPP LTE system

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The Journal of China Universities of Posts and Telecommunications 2014年第2期21卷 63-68页

作者： WANG Ke LI Xi ji hong MA Ze-wen Key Laboratory of Universal Wireless Communications Ministry of Education Beijing University of Posts and Telecommunications

Although the medium access control （MAC） signaling has been well-defined in the 3rd generation partnership project （3GPP） long term evolution （LTE） specifications, the scheduling algorithm crucial to guarantee QoS performance, still remains as open issues. In this article, a traffic-based queue-aware scheduling （TQS） algorithm is proposed for evolved nodeB＇s （eNB＇s） MAC scheduler in 3GPP LTE broadband wireless networks. The proposed TQS is divided into three sub-algorithms： firstly, the authors propose a traffic model construction （TMC） algorithm which can construct a discrete-time Markov-modulated Poisson process （dMMPP） to represent each flow. Secondly, a newly traffic state estimation （TSE） algorithm is designed to obtain the queue＇s analytical statistics. Thirdly, based on the derived results of TSE and the channel states, a scheduling action decision （SAD） algorithm is presented that can adaptively allocate bandwidth to flows by considering both queue states and spectrum efficiency. Simulation shows that the TMC and TSE algorithm can capture the fluctuation of traffic and queue accurately. Moreover, compared with a widely accepted traffic-based scheduling algorithm, the proposed TQS has better average queue length and overflow probability performance.

关键词： MAC scheduling queue analysis dMMPP

Novel incremental relaying protocol based on spatial modulation

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The Journal of China Universities of Posts and Telecommunications 2012年第4期19卷 73-79页

作者： ZHANG Zheng ji hong LI Yi ZHANG He-li School of Telecommunication Engineering Beijing University of Posts and TelecommunicationsBeijing 100876China

This paper presents a novel incremental relaying protocol based on spatial modulation for cooperative transmission over quasi-static rayleigh fading channel, namely spatial modulation incremental relaying （SMIR）, which applies the concept of spatial modulation into incremental relaying. In the proposed protocol, information bits are mapped into two information carrying units： 1） a constellation point in the constellation diagram and 2） the spatial domain, i.e. into the location of a particular cooperative user number. The analytical expression of the frame error rate （FER） for SMIR protocol is derived. Simulation results confirm the presented mathematical analysis and show that SMIR protocol gains 2 and 3 dB in signal to noise ratio （SNR） over the conventional protocol for 3-and 5-bit/symbol transmissions respectively. Moreover, under this protocol the system can achieve a much higher throughput, which means that our proposed protocol brings significant gain in performance.

关键词： SMIR cooperative communication maximum likelihood (ML) detection

Targeted and effective photodynamic therapy for cancer using functionalized nanomaterials

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Acta Pharmaceutica Sinica B 2016年第4期6卷 297-307页

作者： Eun ji hong Dae Gun Choi Min Suk Shim Division of Bioengineering Incheon National University

Photodynamic therapy(PDT) is an emerging, non-invasive therapeutic strategy that involves photosensitizer(PS) drugs and external light for the treatment of diseases. Despite the great progress in PS-mediated PDT, their clinical applications are still hampered by poor water solubility and tissue/cell specificity of conventional PS drugs. Therefore, great efforts have been made towards the development of nanomaterials that can tackle fundamental challenges in conventional PS drug–mediated PDT for cancer treatment. This review highlights recent advances in the development of nano-platforms, in which various functionalized organic and inorganic nanomaterials are integrated with PS drugs, for significantly enhanced efficacy and tumor-selectivity of PDT.

关键词： Organic nanomaterials Inorganic nanomaterials Nanoparticles Photodynamic therapy Photosensitizer Targeted therapy Cancer therapy Near-infrared light

A Reliability Aware Protocol for Cooperative Communication in Cognitive Radio Networks

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International Journal of Automation and computing 2019年第1期16卷 84-92页

作者： Munam Ali Shah Si-jing Zhang hong-ji Yang Department of Computer Science COMSATS Institute of Information Technology Department of Computer Science and Technology University of Bedfordshire Centre for Creative Computing Bath Spa University

One of the challenging tasks in cognitive radio(CR) networks is to agree on a common control channel to exchange control information. This paper presents a novel medium access control(MAC) protocol for CR network which efficiently and intelligently establishes a common control channel between CR nodes. The proposed protocol is the first CR MAC protocol which is hybrid in nature and lies between global common control channel(GCCC) and non-GCCC family of MAC protocols. The dynamic nature of the protocol makes the CR nodes converge on a newly found control channel quicker whenever the interference from a licensed user is sensed. The analytical results show that the dynamic, hybrid and adaptive nature of proposed protocol yields higher throughputs when compared with other CR MAC protocols.

关键词： Cognitive radio common control channel co-operative communication medium access control(MAC)protocols DTMC