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2013 16th International Conference on Computer and information Technology, ICCIT 2013

作者： Kamruzzaman, M.M. Key Lab of Information Coding and Transmission Southwest Jiaotong University ChengduSichuan China

ISBN: (纸本)9781479934973

In this paper, performance of a Turbo Code (TC) and Vertical Bell laboratories Layered Space Time (VBLAST) encoded wireless link is evaluated in the presence of Rayleigh fading for Multiple-Input Multiple-Output (MIMO) system. Turbo encoded bits are modulated using QPSK or 16 QAM or 64 QAM modulator and modulated data are further encoded using VBLAST and then split into n streams which are simultaneously transmitted through n transmit antennas. Simulation results obtained show that coded MIMO system provides 17 to 25 dB coding gain for different combination of transmit and receive antennas at a BER of 10-3 compared to uncoded MIMO system. And there is around 2 to 8 dB gain for increasing number of transmitting antennas from 2 to 3 or 3 to 4. On the other hand, capacities for (2 Tx, 2 Rx), (3 Tx, 3 Rx) and (4 Tx, 4 Rx) are almost same from 0dB to 10dB but change significantly with increasing SNR from 10dB. © 2014 IEEE.

关键词： Quadrature amplitude modulation

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A construction of inter-group complementary codes with flexible ZCZ length

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Journal of Zhejiang University-Science C(Computers and Electronics) 2011年第10期12卷 846-854页

作者： Li-fang FENG Xian-wei ZHOU Ping-zhi FAN School of Information Engineering University of Science and Technology Beijing Beijing 100083 China Provincial Key Lab of Information Coding and Transmission Institute of Mobile Communications Southwest Jiaotong University Chengdu 610031 China

A general construction of inter-group complementary (IGC) codes is proposed based on perfect complementary (PC) codes,interleaving operation,and the orthogonal *** correlation properties of the newly constructed IGC codes can be described as follows:(1) the autocorrelation sidelobes of the codes are zeros in the zero correlation zone (ZCZ);(2) the cross-correlation functions (CCFs) between any two different codes of the same group are zeros in the ZCZ;(3) the CCFs between any two codes of different groups are zeros *** key point of this construction is that the ZCZ length of the generated IGC codes can be chosen *** is well known that there is a limitation between the ZCZ length and the number of mates;that is,the smaller is the length of ZCZ,the more are the IGC codes that can be ***,if we can choose the ZCZ length of the IGC codes flexibly according to the requirement of the system,more users can be accommodated in the system.

关键词： Z-complementary codes Perfect complementary codes Zero correlation zone

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An optimized handover trigger scheme in LTE systems for high-speed railway

An optimized handover trigger scheme in LTE systems for high...

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5th International Workshop on Signal Design and Its Applications in Communications, IWSDA'11

作者： Luo, Wantuan Fang, Xuming Cheng, Meng Zhou, Xiangjuan Provincial Key Lab of Information Coding and Transmission Southwest Jiaotong University Chengdu China

ISBN: (纸本)9781612840468

With the development of high-speed railway all over the world, the reliability and communication of bullet train depends on the wireless communication between train and Base Stations (BSs) along the railroad. Traditional handover scheme of Long Term Evolution (LTE) network is that neighboring cell becomes better than an offset relative to the serving cell during Time To Trigger (TTT), it avoids ping-pong between two cells effectively, but in high-speed railway, it would lead to radio link failure as it can't trigger handover. On the other hand, it would cause false trigger and alternate signaling frequently if just cutting down TTT. This paper includes a brief overview of traditional handover scheme, followed by an analysis of it in high-speed railway based on LTE systems. The analysis emphasizes the effects of velocity on handover. A scheme based on the train's position is proposed. The scheme adjusts TTT and entering and leaving condition of trigger handover at different positions. The simulation results show that the proposed scheme triggers handover more effectively as compared with traditional handover scheme, thus decreases outage probability and improves handover success probability. © 2011 IEEE.

关键词： Railroads

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A physical layer secure wireless communication scheme for high speed railway

A physical layer secure wireless communication scheme for hi...

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6th International Workshop on Signal Design and Its Applications in Communications, IWSDA 2013

作者： Yaping, Cui Fang, Xuming Key Lab of Information Coding and Transmission Southwest Jiaotong University Chengdu 610031 China

ISBN: (纸本)9781467364812

The high speed railway wireless communication system is much different from public wireless communication system, because the service is train control messages, which is closely related to the safety of train transportation. Thus it is much demanding to the security and reliability. To guarantee the train control messages delivery security, secrecy capacity and outage probability at the high speed railway scenario under single-stream beamforming are analyzed and show that the security requirements can not been satisfied. Thus a physical layer secure wireless communications scheme under beamforming with artificial noise is proposed for high speed railway. In this scheme, artificial noise is used in the null space of the main channel only to degrade the eavesdropper's channel. Simulation results illustrate the proposed scheme decreases the outage probability under a certain secrecy capacity demand, and meets the secure communication requirements. © 2013 IEEE.

关键词： Beamforming

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Fractional frequency reuse schemes and performance evaluation for ofdma multi-hop cellular networks

Fractional frequency reuse schemes and performance evaluatio...

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2009 5th International Conference on Testbeds and Research Infrastructures for the Development of Networks and Communities and Workshops, TridentCom 2009

作者： Yue, Zhao Xuming, Fang Xiaopeng, Hu Zhengguang, Zhao Yan, Long Provincial Key Lab of Information Coding and Transmission Southwest Jiaotong University Chengdu 610031 China

ISBN: (纸本)9781424428472

For the next generation wireless communication systems, inter-cell interference (ICI) is the primary cause of performance degradation in cell edge mobile stations of OFDMA multi-hop cellular networks with the frequency reuse pattern (1, 3, 1). This paper introduces a new fractional frequency reuse scheme to assign radio resources in OFDMA multi-hop networks to reduce inter-cell interference and maintain the sector frequency reuse factor at 1. Through the numerical analysis, we find that this scheme can yield higher SINR and improve the system capacity. Furthermore, the results also indicate that fractional frequency reuse relay system with local forwarding scheme can achieve higher throughput than local forwarding scheme in conventional relay system.

关键词： Frequency division multiple access

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An energy saving radio resource allocation in OFDMA-based cellular relay networks

An energy saving radio resource allocation in OFDMA-based ce...

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5th International Workshop on Signal Design and Its Applications in Communications, IWSDA'11

作者： Huang, Bo Fang, Xuming Chen, Yu Provincial Key Lab of Information Coding and Transmission Southwest Jiaotong University Chengdu 610031 China

ISBN: (纸本)9781612840468

In the OFDMA-based cellular relay networks, relay selection and resource allocation are the main problem to be solved. Many present works about resource allocation are for the goal of throughput maximization. In this paper, we propose an adaptive resources allocation algorithm joint relay selection, sub-carrier assignment and power allocation for the goal of energy saving to ensure users' QoS, and the relay scenario is DF, TDD and two-hop single-relay. Simulation results show that the proposed algorithm consumes less energy to transmit the same bits than the greedy energy saving scheme though its spectrum efficiency is worse. © 2011 IEEE.

关键词： Resource allocation

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Performance of Turbo coded wireless link for SISO-OFDM, SIMO-OFDM, MISO-OFDM and MIMO-OFDM system

Performance of Turbo coded wireless link for SISO-OFDM, SIMO...

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14th International Conference on Computer and information Technology, ICCIT 2011

作者： Kamruzzaman, M.M. Key Lab. of Information Coding and Transmission Southwest Jiatong University Chengdu Sichuan China

ISBN: (纸本)9781612849065

In this paper, performance of a Turbo coded OFDM wireless link is evaluated in the presence of Rayleigh fading for SISO, SIMO, MISO and MIMO system. Data are encoded using turbo encoder then modulated by QPSK or 16 QAM or 64 QAM and further encoded using STBC, and the encoded data are split into n streams which are modulated by OFDM and simultaneously transmitted using n transmit antennas. It is observed that the turbo coded SISO-OFDM system provides 21 dB coding gain at 10-4, turbo coded SIMO-OFDM system provides 20 and 13 db coding gain for 2 and 4 receive antennas respectively at a BER of 10-6, turbo coded MISO-OFDM system provides 17 and 12 dB coding gain for 2 and 4 transmit antennas respectively at a BER of 10-6 and turbo coded MIMO-OFDM system provides 11 to 13 dB coding gain for different combination of transmit and receive antennas at BER 10-6 compare to uncoded SISO-OFDM, SIMO-OFDM, MISO-OFDM and MIMO-OFDM system. © 2011 IEEE.

关键词： Orthogonal frequency division multiplexing

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A relative risk model for anomaly detection in wireless sensor networks

A relative risk model for anomaly detection in wireless sens...

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2008 International Conference on Wireless Communications, Networking and Mobile Computing, WiCOM 2008

作者： Jiayu, Tang Pingzhi, Fan Key Lab. of Information Coding and Transmission IMC Southwest Jiaotong University Chengdu China

ISBN: (纸本)9781424421084

Localization anomaly detection (LAD) for a wireless sensor network (WSN) plays a prominent role in defending against attacks on localization services. However, it is a difficult task to evaluate the effectiveness of the anomaly detection scheme according to complexity and uncertainty in various applications. This paper presents a relative risk model approach that was proposed for ecological risk assessment (ERA) to tackle this problem. The problem formulation and model-building process is described in detail. Our numerical simulation demonstrates that this relative risk model method is quite effective to the quantitative assessment of vulnerability analysis in wireless sensor networks. © 2008 IEEE.

关键词： Wireless sensor networks

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New sets of low-hit-zone frequency-hopping sequence with optimal maximum periodic partial Hamming correlation

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Science China Chemistry 2015年第12期58卷 158-172页

作者： WANG ChangYuan PENG DaiYuan HAN HongYu ZHOU LiMengNan Provincial Key Lab of Information Coding and Transmission Institute of Mobile CommunicationsSouthwest Jiaotong University

Recently, Chung et al. gave a general method to construct frequency-hopping sequence set(FHS set) with low-hit-zone(LHZ FHS set) by the Cartesian product. In their paper, Theorems 5 and 8 claim that k FHS sets whose maximum periodic Hamming correlation is 0 at the origin result in an LHZ FHS set based on the Cartesian product, and Proposition 4 presented an upper bound of the maximum periodic Hamming correlation of FHSs. However, their statements are imperfect or incorrect. In this paper, we give counterexamples and make corrections to them. Furthermore, based on the Cartesian product, we construct two classes of LHZ FHS sets with optimal maximum periodic partial Hamming correlation property. It is shown that new FHS sets are optimal by the maximum periodic partial Hamming correlation bound of LHZ FHS set.

关键词： frequency-hopping sequence maximum periodic partial Hamming correlation maximum periodicHamming correlation low-hit-zone cartesian product

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Improved method for detecting the short cycles of LDPC codes

Improved method for detecting the short cycles of LDPC codes

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2010 IEEE International Conference on information Theory and information Security, ICITIS 2010

作者： Hu, Pan Zhao, Hongyu Key Lab. of Information Coding and Transmission Southwest Jiao tong University Chengdu China

ISBN: (纸本)9781424469406

It is well known that the short cycles in Tanner Graph (TG) greatly impact on the iterative decoding performance of low density parity check (LDPC) codes. In previous literature two methods can be found for detecting such short cycles. This paper presents an improved version of previous Jun Fan's method, which is based on combinational analysis and enumeration of the check matrix patterns caused by cycles of length of 4, 6, 8 and 10 in the corresponding TG. The improved method can more exactly detect the cycles of length greater than 4 in comparison with Jun Fan's method. The validation of the proposed method can be verified by the detection results of short cycles for some LPDC codes. © 2010 IEEE.

关键词： Iterative decoding

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