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Beamforming based decode-and-forward cooperation via backward synchronization

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Science china(Information Sciences) 2012年第4期55卷 805-814页

作者： LI YuBo,yin qinye & wang chen ministry of Education key lab for intelligent networks and network security,xi’an jiaotong university,xi’an 71.049,china 1. ministry of Education {1. lab for intelligent networks and network security Xi’an Jiaotong University Xi’an 710049 China

In this paper,a beamforming (BF) based cooperation scheme with decode-and-forward (DF) protocol is proposed and its performance analysis is ***,to solve the issue of carrier synchronization in distributed networks,a backward synchronization (B-Sync) method is introduced,where participating relays synchronize to the reference carrier broadcast by the destination and make signals superimposed coherently at the destination without any phase ***,based on B-sync,a cooperation scheme with DF protocol is proposed to carry out BF forwarding among *** outage probability of this scheme is derived and analyzed,which shows that the full diversity order can be achieved by the proposed ***,symbol error probability (SEP) analysis is presented to evaluate the practical *** results validate the analysis,and show that the proposed scheme outperforms other existing ones in terms of outage probability and SEP.

关键词： cooperative diversity distributed beamforming outage probability symbol error probability decode-and-forward

Outage-optimal relaying through opportunistic hybrid forward cooperation

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Science china(Information Sciences) 2011年第6期54卷 1264-1273页

作者： LI YuBo , yin qinye & wang JunSong ministry of Education key lab for intelligent networks and network security, xi’an jiaotong university, xi’an 71.049, china 1. ministry of Education {1. lab for intelligent networks and network security Xi’an Jiaotong University Xi’an 710049 China

In this paper, a new scheme based on relay selection and data forwarding in multi-relay cooperative networks is introduced. Unlike most existing solutions focused on amplify-and-forward (AF) or decode-and-forward (DF) protocol separately, the proposed hybrid forward (HF) scheme takes advantage of both AF and DF protocols in relay forwarding. Based on theoretical analysis, a closed-form expression for the tight lower bound of its outage probability is derived, and further performance analysis is also presented. Then, in total power restricted networks, an optimal power allocation strategy between the source and the selected relay is developed to minimize the outage probability. Simulations are carried out finally, which validate the analysis and show that the HF scheme outperforms other existing ones in terms of outage probability.

关键词： cooperative diversity opportunistic cooperation outage probability power allocation diversity-multiplexing-tradeoff

AOD estimation in WSN localization system with synthetic aperture technique

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Science china(Information Sciences) 2012年第10期55卷 2216-2225页

作者： wang wenjie,YAO BoBin & yin qinye MOE key lab for intelligent networks and network security,School of Electronic and Information Engineering,xi’an jiaotong university,xi’an 71.049,china 1. MOE key {1. for intelligent networks and network security School of Electronic and Information Engineering Xi’an Jiaotong University Xi’an 710049 China

Angel of departure(AOD) based distributed localization scheme in wireless sensor networks allows the single antenna sensor node to estimate its own AOD information by an equivalent antenna array for further position ***,the condition that the number of antennas at the multi-antenna agent/anchor node should be larger than the number of multipath signal components(MPCs) constrains its actual *** this paper,we provide a more practical approach to achieve AOD information estimation under multipath *** that the sensor node can not identify the line of sight(LOS) signal component due to the insufficient degree of freedom,which is determined by the above limiting condition,we introduce a synthetic aperture technique with the aid of a fast moving multi-antenna agent/anchor *** operation greatly enlarges the degree of freedom of the equivalent antenna array constructed at sensor node end but without requiring other extra physical antennas equipped at agent/anchor node or sensor node end,which means that it relaxes the limiting ***,the AOD information of LOS signal component can be estimated and extracted successfully in complex multipath *** analysis proves the effectiveness of our proposed synthetic aperture technique and numerical simulations show great performance improvement.

关键词： angle of departure degree of freedom synthetic aperture wireless sensor networks

Pilot-aided channel estimation for CDD-OFDM systems

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Science china(Information Sciences) 2010年第2期53卷 379-389页

作者： FAN JianCun , yin qinye & wang wenjie MOE key laboratory for intelligent networks and network security, Institute of Information Engineering, xi’an jiaotong university, xi’an 71.049, china 1. MOE key {1.oratory for intelligent networks and network security Institute of Information Engineering Xi’an Jiaotong University Xi’an 710049 China

Cyclic delay diversity (CDD) is a low-complexity transmit diversity technique for coded orthogonal frequency division multiplexing (OFDM), which transforms a multiple-input channel into an equivalent singleinput channel with increased frequency selectivity and provides additional frequency diversity. However, it makes channel estimation more difficult due to the increased frequency selectivity. In this paper, focusing on the direct estimation of the equivalent single-input channel for CDD-OFDM systems, a cyclic cross-correlation channel estimation method based on the equispaced constant-modulus pilot structure is first proposed. Using the statistical parameters of the channel and noise derived by the cyclic cross-correlation channel estimation, an improved channel estimation method based on the Wiener filter is proposed to reduce the estimation error further. Lastly, computation simulations are given to demonstrate the effectiveness of two proposed channel estimation methods for CDD-OFDM systems.

关键词： channel estimation cyclic delay diversity OFDM systems cyclic cross-correlation Wiener filter

Optimal user scheduling and power control in multi-user cognitive broadcast systems

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Science china(Information Sciences) 2012年第6期55卷 1402-1414页

作者： wang QunHuan 1,2,3,wang HuiMing 1,2,3 & yin qinye 1,3 1 School of Electronic and Information Engineering,xi'an jiaotong university,xi'an 71.049,china 2 State key lab for Integrated Services networks,xidian university,xi'an 710071,china 3 ministry of Education key lab for intelligent networks and network security,xi'an jiaotong university,xi'an 710071,china. 1. School of Electronic and Information Engineering Xi’an Jiaotong University Xi’an 710049 China2. State Key Lab for Integrated Services Networks Xidian University Xi’an 710071 China3. Ministry of Education Key Lab for Intelligent Networks and Network Security Xi’an Jiaotong University Xi’an 710071 China

Cognitive radio systems should not only have the ability to sense and exploit "frequency spectrum holes",but also the ability to sense and utilize "spatial spectrum holes".In this paper,we consider the issue of maximizing the throughput of the cognitive systems by fully utilizing "spatial spectrum holes" brought in by multiple cognitive users,in the scenario where a pair of licensed users and a cognitive broadcast system share multiple spectrum *** exploiting the channel reciprocity under the premise that the licensed system adopts the time-division-duplexing (TDD) mode,we propose a more practical cognitive access scheme that can sense the interference at the licensed user caused by the cognitive transmitter,based on the existing feedback signals from the licensed user to the licensed base *** both interferences from the licensed base station to the cognitive receiver and from the cognitive transmitter to the licensed user into consideration,we investigate the optimal user scheduling and power allocation scheme that can maximize the ergodic sum rate of the cognitive *** show that scheduling the user whose channel gain to interference and noise ratio (CGINR) is the largest for each frequency band is *** also derive the dynamic power allocation scheme meeting the three practical constraints,i.e.,the transmitter's average transmission power constraint,the power amplifier's instantaneous transmission power constraint,and the interference power constraint at the licensed *** result shows that in different coherent time intervals and different frequency bands,the power allocation has a multi-level waterfilling *** analysis shows that the strategy scheduling user with the largest CGINR introduces significant performance improvement compared with the traditional strategy scheduling user with the largest channel gain to noise ratio (CGNR).We also illustrate the impact of power constraints and the number of users on system p

关键词： cognitive radio distributed spatial spectrum holes opportunistic scheduling power allocation

A wireless secret key generation method based on Chinese remainder theorem in FDD systems

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Science china(Information Sciences) 2012年第7期55卷 1605-1616页

作者： wang wenjie 1,JIANG HongYan 1 ,xiA xiangGen 2,3 ,MU Pengcheng 1 & yin qinye 1 1 ministry of Education key lab for intelligent networks and network security,xi’an jiaotong university,xi’an 71.049,china 2 Electrical and Computer Engineering,university of Delaware,Newark,DE 19716,USA 3 Chonbuk National university,Jeonju,South Korea 1. ministry of Education {1. lab for intelligent networks and network security Xi’an Jiaotong University Xi’an 710049 China2. Electrical and Computer Engineering University of Delaware Newark DE 19716 USA3. Chonbuk National University Jeonju South Korea

The wireless physical channel parameters are recently used to provide secret ***,the key generation usually suffers from the quantization errors due to the noise,which decreases the key agreement ratio (KAR) between authorized *** existing approaches achieve high KAR by discarding some channel parameters which may lower the key generation efficiency and therefore lower the encryption *** the frequency-division duplex (FDD) systems,the number of reciprocal parameters,such as the multipath angle and delay,is *** how to find a quantization method with high KAR and encryption strength is one of the major problems for secret key generation in FDD *** this paper,a robust quantization scheme based on grouping and shifting is proposed,in which all the available parameters are used for key *** addition,a key mapping method with error correction based on Chinese remainder theorem (CRT) is proposed to further improve the KAR *** demonstrate the effectiveness of the proposed method.

关键词： wireless communication security secret key generation FDD CRT angle and delay estimation

Phase detection based range estimation with a dual-band robust Chinese remainder theorem

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Science china(Information Sciences) 2014年第2期57卷 18-26页

作者： YANG Bin wang {1. xiA xiangGen yin qinye ministry of Education (MOE) {1. laboratory for intelligent networks and network security School of Electronics and Information EngineeringXi’an Jiaotong University Department of Electrical and Computer Engineering University of Delaware

Range estimation with multifrequency phases is a common practice in localization *** challenge of this method is the phase *** Chinese remainder theorem(CRT)based phase unwrapping algorithms have been proposed to solve the problem,where the wavelengths of the multifrequency signals need to be pair-wisely co-prime after they are divided by their greatest common divisor(gcd).This condition may limit the application in *** this paper,a novel way based on a dual-band robust CRT is presented to reconstruct the distance from dual-band wrapped phases,where the pair-wisely co-prime condition is not necessarily *** more wrapped phases are involved to reconstruct the distance,the method can significantly enlarge the reconstruction range compared to the single band solution.

关键词： range estimation Chinese remainder theorem(CRT) robustness dual band

An energy-efficient geographic routing based on cooperative transmission in wireless sensor networks

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Science china(Information Sciences) 2013年第7期56卷 42-51页

作者： LI Bin wang {1. yin qinye LI Hongxiang YANG Rong ministry of Education {1. laboratory for intelligent networks and network security Xi'an Jiaotong University Department of Electrical and Computer Engineering University of Louisville National Research Institute of Radio Spectrum Management

In this paper, we propose an energy-efficient cooperative geographic routing (ECGR) to reach energy-efficient routing in wireless sensor networks (WSN). ECGR takes full advantage of cooperative diversity and geographic routing. At physical layer, cooperative nodes transmit the same packet in a cooperative way to achieve farther transmission distance of each hop without more energy consumption. While at the {1. layer, ECGR adaptively selects the appropriate cooperative nodes to form forwarding clusters to forward the packet to the destination when we consider energy consumption and geographic information of the sensor nodes. Meanwhile, in order to fully assess the energy consumption, we take circuit energy consumption of the sensor nodes into consideration. According to the description above, we increase the transmit distance of each hop; and thereby reducing and balancing the overall {1. energy consumption among nodes to extend the lifetime of the {1..

关键词： wireless sensor networks geographic routing transmit diversity multi-sensor diversity circuit energy consumption

Two-step transmission with artificial noise for secure wireless SIMO communications

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Science china(Information Sciences) 2015年第4期58卷 115-127页

作者： wang Bo MU Peng{1.g YANG PeiZhi yin qinye ministry of Education {1. lab for intelligent networks and network security School of Electronic and Information Engineering Xi’an Jiaotong University

The issue of physical layer security of the wireless single-input multiple-output(SIMO) system is addressed in this paper. We propose a two-step transmission scheme with artificial noise to improve the security and the scheme does not require the channel state information of the eavesdropper. In the first step, the destination which has multiple antennas generates a random reference symbol and artificial noise and transmits them in the direction of the source and its orthogonal space, respectively. The reference symbol is received by the source without being polluted by the artificial noise, while it is jammed by the artificial noise for the eavesdropper. In the second step, the symbol of the source is multiplied by the received reference symbol and then transmitted. Finally, the destination can directly estimate the symbol of the source using the reference symbol. However, the eavesdropper needs to additionally estimate the reference symbol for demodulating the symbol of the source, which usually obtains an inaccurate result due to the artificial noise. The informationtheoretic security of our scheme is analyzed and a lower bound of the achievable secrecy rate is derived. The performance of the new scheme is compared with that of the traditional approach under different input signals through numerical simulations. The results show that the proposed scheme outperforms the traditional SIMO approach especially in the high SNR region.

关键词： wireless communication physical layer security multi-antenna SIMO artificial noise