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Multiple symbols soft-decision metrics for coded frequency-shift keying signals

Science China(information Sciences) 2013年第2期56卷 49-56页

作者： MA Zheng PERSSON Danie LARSSON Erik G. FAN PingZhi Provincial Key Lab of Information Coding and Transmission Southwest Jiaotong University National Mobile Communications Research Laboratory Southeast University Department of Electrical Engineering Linkping University

This paper derives a novel multiple symbols soft-decision metrics for frequency-shift keying signals which are affected by additive symmetric α -stable (S α S) noise and fading. The approximate metric, which is for the case where channel state information (phases, amplitudes, and noise dispersion parameter) is unknown is obtained based on a generalized-likelihood ratio (GLR) approach. The metric is obtained in closed form and proved to be effective. The performances of the multiple symbols soft-decision metrics are compared numerically for a turbo-coded system. The proposed multiple symbols metric provides substantial improvement over earlier single-symbol metrics.

关键词： multiple symbols detection generalized likelihood ratio (GLR) symmetric α -stable (S α S) noise fading channel

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A new set of optimal frequency-hopping sequences

A new set of optimal frequency-hopping sequences

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作者： Liu, Fang Peng, Daiyuan Tang, Xiaohu Provincial Key Lab of Information Coding and Transmission School of Information Science and Technology Southwest Jiaotong University Chengdu China

In frequency-hopping (FH) multiple access systems, frequency-hopping sequences (FHSs) with optimal Hamming correlation properties are needed. Based on the d-form functions with ideal autocorrelation properties, a new set of FHSs is constructed. The new FHS set is optimal with respect to the Peng-Fan bounds and each FHS in the set is optimal with respect to the Lempel-Greenberger bound. Copyright © 2010.

关键词： Autocorrelation

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The average hamming correlation for the cubic polynomial hopping sequences

The average hamming correlation for the cubic polynomial hop...

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International Wireless Communications and Mobile Computing Conference, IWCMC 2008

作者： Peng, D.Y. Niu, X.H. Tang, X.H. Chen, Q.C. IEEE Key Lab. of Information Coding and Transmission Southwest Jiaotong University Chengdu Sichuan China

ISBN: (纸本)9781424422029

The average Hamming correlation is an important performance indicator of the frequency hopping sequences. In this paper, the lower bound on the average Hamming correlation for frequency hopping sequences with respect to the size q of the frequency slot set, the sequence length L, the family size M, the average Hamming autocorrelation Aa and the average Hamming crosscorrelation Ac, is established. The average Hamming correlation for the cubic polynomials hopping sequences over a finite field GF(p) is also derived and discussed. It is shown that the cubic polynomials hopping sequences over a finite field GF(p) are the optimal average Hamming correlation sets. © 2008 IEEE.

关键词： Frequency hopping

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Low-complexity primary synchronization detection algorithm in FDD-LTE system

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Tiedao Xuebao/Journal of the China Railway Society 2013年第1期35卷 71-76页

作者： Peng, Peng Ma, Zheng Provincial Key Lab. of Information Coding and Transmission Southwest Jiaotong University Chengdu 610031 China

Primary synchronization detection is used as the first step for cell searching in the FDD-LTE system, which completes the functions of timing synchronization, cell ID identifying and frequency offset estimation and so on. Fast, efficient and accurate primary synchronization detection algorithms are the preconditions to let users access to the proper cell quickly. Introducing several classic timing synchronization algorithms, the paper mainly focused on the timing synchronization algorithm, i. e., the primary synchronization detection algorithm, for orthogonal frequency division modulation (OFDM) in the FDD-LTE system. Meanwhile, the improved method based on the primary synchronization detection algorithm was proposed to achieve lower *** theoretical analysis and simulation results indicate that the proposed algorithm is characterized by low computation complexity and fast detection convergence.

关键词： Cells

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A novel handover scheme with relay technique in GSM-R network

A novel handover scheme with relay technique in GSM-R networ...

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2009 4th International Conference on Communications and Networking in China, CHINACOM 2009

作者： Zheng, Xiang Fei, Yang Key Lab. of Information Coding and Transmission Southwest Jiaotong University Chengdu 610031 Sichuan China

ISBN: (纸本)9781424443376

GSM-R (GSM for Railway) network is a professional cellular network which is used for railway transportation. Unlike mobiles with low speed in regular GSM network, in GSM-R network the signals received by mobiles on high speed trains may suffer severe Doppler shift and other interferences. Therefore, measurement of these tainted signals may cause wrong handover decisions, leading to lower probability of successful handover, hence the safety and reliability of GSM-R network are reduced significantly. In this paper, a novel handover scheme with relay technique in GSM-R network is proposed, which involves measurement of signals from relay stations in handover process. Numerical results show that the outage rate of handover using this new scheme is obviously smaller than that without relay stations, thus higher probability of successful handover is achieved.

关键词： Railroads

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On the orthogonality of signal tones in SFH/MFSK systems over multipath fading channels

On the orthogonality of signal tones in SFH/MFSK systems ove...

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IET 2nd International Conference on Wireless, Mobile and Multimedia Networks, ICWMMN 2008

作者： Wang, Xiaoning Fan, Pingzhi Peng, Daiyuan Provincial Key Lab of Information Coding and Transmission Institute of Mobile Communications Southwest Jiaotong University Chengdu 610031 China

ISBN: (纸本)9780863419256

In this paper, the effect of multipath fading on orthogonality of signal tones in slow frequency-hopping communication system using M-ary frequency-shift keying modulation with non-coherent demodulation (SFH/MFSK) is analyzed. A general expression of orthogonality loss factor Djnl is derived, which is determined not only by multipath delays, signal strength fading and synchronization time error, but also by phase variation caused by multipath delays. The results obtained here are also more general than that of traditional FH system which transmits only one symbol per hop. Numerical results demonstrate that the effects vary greatly with different phase variations.

关键词： Multipath fading

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A cross-layer fast handoff protocol for vehicle communication system

A cross-layer fast handoff protocol for vehicle communicatio...

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IET Conference on Wireless, Mobile and Sensor Networks 2007, CCWMSN'07

作者： Meng, Xie Xuming, Fang Qiang, Shen Provincial Key Lab. of Information Coding and Transmission Southwest Jiaotong University Chengdu 610031 China National Mobile Communication Research Lab. Southeast University Nanjing 210096 China

ISBN: (纸本)9780863418365

The main purpose of handoff protocol is to provide high data rate and seamless supporting real-time services in the vehicle communication system. Potentially, Wireless Mesh Network (WMN) is one of the best answers to the vehicle communication system. How to provide efficient handoff protocol in the vehicle communication system is the major issue of our design. We analyzed the mathematical module of the vehicle communication system in this paper. Then considering a typical vehicle communication system, we propose a Cross-layer Fast Handoff Protocol (CFHP) which takes into account the signal strength, hops and link state. Compared with the existing AODV based handoff protocols, our protocol with fast handoff mechanism improves the system throughput and the delivery ratio significantly.

关键词： information services

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A low-complexity scheduling scheme for multiuser MIMO system based on tomlinson-harashima precoding

A low-complexity scheduling scheme for multiuser MIMO system...

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

作者： Liu, Heng Hao, Li Fan, Pingzhi Key Lab. of Information Coding and Transmission Institute of Mobile Communication Southwest Jiaotong University Chengdu China

ISBN: (纸本)9781424469406

This paper addresses the scheduling problem for multiuser multi-input multi-output (MU-MIMO) system based on Tomlinson-Harashima Precoding (THP). By considering the channel gain and channel correlation jointly, a low-complexity multiuser scheduling approach is proposed. Compared with the existing scheduling schemes, the proposed scheme can avoid complicated searching process, and thus reduce the scheduling burden at the MAC layer significantly. Simulation results show the sum rate performance of the proposed scheme is nearly optimal although its complexity is very low. © 2010 IEEE.

关键词： MIMO systems

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Interference coordination in compact frequency reuse for multihop cellular networks

Interference coordination in compact frequency reuse for mul...

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作者： Zhao, Yue Fang, Xuming Zhao, Zhengguang Provincial Key Lab of Information Coding and Transmission Institute of Mobile Communications Southwest Jiaotong University Chengdu 610031 Sichuan China

Continuously increasing the bandwidth to enhance the capacity is impractical because of the scarcity of spectrum availab.lity. Fortunately, on the basis of the characteristics of the multihop cellular networks (MCNs), a new compact frequency reuse scheme has been proposed to provide higher spectrum utilization efficiency and larger capacity without increasing the cost on network. Base stations (BSs) and relay stations (RSs) could transmit simultaneously on the same frequency according to the compact frequency reuse scheme. In this situation, however, mobile stations (MSs) near the coverage boundary will suffer serious interference and their traffic quality can hardly be guaranteed. In order to mitigate the interference while maintaining high spectrum utilization efficiency, this paper introduces a fractional frequency reuse (FFR) scheme into multihop cellular networks, in which the principle of FFR scheme and characteristics of frequency resources configurations are described, then the transmission (Tx) power consumption of BS and RSs is analyzed. The proposed scheme can both meet the requirement of high traffic load in future cellular system and maximize the benefit by reducing the Tx power consumption. Numerical results demonstrate that the proposed FFR in compact frequency reuse achieves higher cell coverage probability and larger capacity with respect to the conventional schemes. Copyright © 2010.

关键词： Electric power utilization

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An improved AODV routing protocol with network coding in wireless ad hoc network

An improved AODV routing protocol with network coding in wir...

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IET Conference on Wireless, Mobile and Sensor Networks 2007, CCWMSN'07

作者： Xiang, Zheng Fang, Xuming Key Lab. of Information Coding and Transmission Sichuan Province Southwest Jiaotong University Chengdu 610031 Sichuan China

ISBN: (纸本)9780863418365

This paper introduces a practical scheme in order to improve multi-hop throughput as well as to minimize packet's average end to end delay by incorporating network coding, which is at present a widely discussed technique in multicast, with AODV in wireless Ad Hoc networks. This scheme is simple and easily implemented with modest overhead, and the simulation results show that this scheme can achieve higher throughput and much smaller packet's average end to end delay in certain network topology.

关键词： Routing protocols

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