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Achievable bit rates of cognitive user with Vandermonde precoder in cognitive radio network

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Science china(Information Sciences) 2011年第7期54卷 1471-1480页

作者： xu xiaorong 1,ZHANG JianWu 1 & {2. baoyu 2.1 College of Telecommunication Engineering,Hangzhou Dianzi university,Hangzhou 310018,china 2.institute of signal processing and transmission,nanjing university of {12. and Telecommunications,nanjing 2.0003,china 1. College of Telecommunication Engineering Hangzhou Dianzi University Hangzhou 310018 China2. Institute of Signal Processing and Transmission Nanjing University of Posts and Telecommunications Nanjing 210003 China

In cognitive radio network (CRN) where primary user (PU) and secondary user (SU) wish to communicate with their corresponding receivers simultaneously over frequency selective fading channels,the interference between PU and SU should be eliminated in order to realize spectrum *** division multiple access (PDMA) that implements Vandermonde precoder in cognitive orthogonal frequency division multiplexing (OFDM) is proposed,which benefits from the frequency selectivity of the cognitive channel to form a frequency *** precoder enables SUs to achieve higher bit rate with optimal power allocation strategy under the condition of PU interference *** and simulation results are presented to prove theoretical *** is shown that,achievable bit rates (ABR) of SU could be achieved with optimal power allocation scheme in ***,it is also verified that,with Vandermonde precoder to form PDMA,SU’s signal-to-noise ratio (SNR) and the target rate of PU could impact the ABR of SU significantly in CRN.

关键词： achievable bit rates (ABR) Vandermonde precoder precoder division multiple access (PDMA) optimal power allocation cognitive radio network (CRN)

Robust cooperative spectrum sensing schemes for fading channels in cognitive radio networks

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Science china(Information Sciences) 2011年第2期54卷 348-359页

作者： YUE WenJing1,2. zheng baoyu1,2. MENG QingMin1, CUI JingWu1 & XIE PeiZhong1 {2. of signal processing and transmission, nanjing university of posts and Telecommunications, nanjing 2.0003, china 2.epartment of Electronic Engineering, Shanghai Jiaotong university, Shanghai 2.02.0, china 1. institute of signal {2. and transmission Nanjing University of Posts and Telecommunications Nanjing 210003 China2. Department of Electronic Engineering Shanghai Jiaotong University Shanghai 200240 China

In cognitive radio systems, cooperative spectrum sensing can detect the presence of the primary user accurately. In practice, however, since the sensing observations are forwarded to a data collector through fading channels, the sensing performance is severely degraded. To deal with this problem, in this paper, we first propose a secondary user selection based cooperative spectrum sensing method to improve sensing performance by decreasing the reporting errors introduced by the fading channels. More specifically, only the secondary users with better signal-to-noise ratio (SNR) for reporting channels are allowed to send their local binary decisions (0 or 1) to the data collector while the others will send nothing. Additionally, we further propose a diversity based cooperative spectrum sensing method which applies existing space-time coding. By exploiting space diversity in CR network, the reporting errors introduced by the fading channel can be decreased and then the sensing performance is improved significantly. For either proposed cooperative spectrum sensing method, the sensing performance is derived and the analytical performance results are given. Our analysis and numerical results verify that proposed methods outperform the conventional cooperative spectrum sensing with OR-rule by taking into account the error effect on the reporting channels.

关键词： cognitive radio (CR) spectrum sensing energy detection diversity technique space-time coding

Performance evaluation of half-duplex relay-based opportunistic cooperation diversity

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Science china(Information Sciences) 2010年第2期53卷 325-334页

作者： ZOU YuLong , zheng baoyu & ZHU Jia {2. of signal processing and transmission, nanjing university of posts and Telecommunications, nanjing 2.0003, china 1. institute of signal {2. and transmission Nanjing University of Posts and Telecommunications Nanjing 210003 China

Cooperative diversity is proposed as a means to improve the wireless transmission performance, which can effectively combat the wireless fading through sharing the antennas between source and relay nodes. In this paper, considering the practicability, we investigate the use of half-duplex relay, rather than full-duplex relay, for the opportunistic cooperation diversity. Two combining methods, namely selection diversity combining (SDC) and maximum ratio combining (MRC), are utilized for the implementation of the half-duplex relay-based opportunistic cooperation. Closed-form expressions of outage probability are derived for the proposed oppor- tunistic cooperation as well as the known deterministic cooperation over Rayleigh fading channels. Numerical results show that the opportunistic cooperation is superior to the traditional deterministic cooperation in terms of outage probability and, moreover, the MRC-based case outperforms the SDC-based case no matter which duplex mode relay (i.e., half-duplex and full-duplex) is used for the opportunistic cooperation.

关键词： half-duplex relay cooperative diversity SDC MRC outage probability

Linear beamformer schemes with simple relay selection in MIMO relay networks

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The Journal of china Universities of posts and Telecommunications 2008年第4期15卷 24-29+39页

作者： MENG Qing-min 1,2. PAN Su1, zheng Bao-yu1, ZHU Hong-bo1, YOU Xiao-hu2.1. Jiangsu Key Laboratory of Wireless Communications and institute of {2. processing and transmission, nanjing university of posts and Telecommunications, nanjing 2.0003, china 2. National Mobile Communications Research Lab, Southeast university, nanjing 2.0096, china [a]Jiangsu Key Laboratory of Wireless Communications and institute of signal {2. and transmission nanjing university of {2. and Telecommunications nanjing 2.0003 china [b]National Mobile Communications Research Lab Southeast university nanjing 2.0096 china

This article considers a wireless multi-hop/mesh network where single multi-antenna source-destination pair communicates through a selected relay subset using simple relay selection under the constraint of fixed relay’s number. Compared with random selection, the simple relay selection can yield certain capacity advantages while linear zero-forcing (ZF) receiver and linear beamformer are considered at the relay. For match-filter (MF) beamformer and amplified-and-forward (AF) beamformer with a fixed number of relays, the capacities are given. Furthermore, we extend the simple selection methods to the relaying scheme with orthogonal-triangular (QR) beamformer and investigate these linear beamformer schemes over spatially correlated multi-input multi-output (MIMO) links for both the backward and forward channel over the two-hop MIMO relay networks.

关键词： wireless mesh networks multi-hop relaying capacity beamformer

Optimal power allocation for cognitive relay networks: amplify-and-forward versus selection relay

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Science china(Information Sciences) 2011年第4期54卷 861-872页

作者： YUE WenJing 1,2.zheng baoyu 1,2.MENG QingMin 1,YUE WenJie 3 & CUI JingWu 1 1 {2. of signal processing and transmission,nanjing university of posts and Telecommunications,nanjing 2.0003,china 2.Department of Electronic Engineering,Shanghai Jiaotong university,Shanghai 2.02.0,china 3 Shanxi {2. of Educational Science,Taiyuan 030009,china 1. institute of signal {2. and transmission Nanjing University of Posts and Telecommunications Nanjing 210003 China2. Department of Electronic Engineering Shanghai Jiaotong University Shanghai 200240 China3. Shanxi Institute of Educational Science Taiyuan 030009 China

We consider a cognitive relay network which is defined by a source,a destination,and cognitive relay nodes and primary user *** this network,a source is assisted by cognitive relay nodes which allow coexisting with primary user nodes by imposing severe constraints on the transmission power so that they operate below the noise floor of primary user *** this paper,we mainly study the power allocation strategies of this system to minimize the outage probability subject to total and individual power constraints for cognitive relay nodes and subject to interference constraints for primary user nodes.A relay transmission scheme,namely amplify-and-forward (AF),is *** first present an optimal power allocation (OPA) scheme to minimize the system outage probability,based on instantaneous channel state information among the source,destination and relay nodes and mean channel gains between primary user nodes and cognitive ***,we propose a selection AF scheme (S-AF) where the single best relay is chosen to assist in the transmission and study power allocation strategy for S-AF to minimize outage *** analytical power allocation strategies have been validated through numerical *** results indicate that the AF with OPA and S-AF with OPA have significantly better outage behavior and average throughput than AF and S-AF schemes *** also find that S-AF with OPA achieves a higher throughput,and hence lower outage probability than AF with OPA.

关键词： cognitive radio (CR) relay networks power allocation outage probability

Cyclostationary Property Based Spectrum Sensing Algorithms for Primary Detection in Cognitive Radio Systems

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Journal of Shanghai Jiaotong university(Science) 2009年第6期14卷 676-680页

作者：岳文静郑宝玉孟庆民 Department of Electronic Engineering Shanghai Jiaotong University institute of signal {2. and transmission Nanjing University of Posts and Telecommunications

To implement the primary signal without interference in cognitive radio systems, cognitive radios can detect the presence of the primary user in low SNR. Currently, energy detector is the most common way of spectrum sensing because of its low computational complexity. However, performunce of the method will be possibly degraded due to the uncertainty noise. This paper illustrates the benefits of one-order and two-order cyclostationary properties of primary user＇s signals in time domain. These feature detection techniques in time domain possess the advantages of simple structure and low computational complexity comparing with spectral feature detection methods. Furthermore, performance of the one-order and two-order feature detection is studied and the analytical results are given. Our analysis and numerical results show that the sensing performance of the one-order feature detection is improved significantly comparing with conventional energy detector since it is robust to noise. Meanwhile, numerical results show that the two-order feature detection technique is better than the one-order feature detection. However, this benefit comes at the cost of hardware burdens and power consumption due to the additional multiplying algorithm.

关键词： cognitive radio spectrum sensing cyclostationary feature detection

Dual-band dynamic reconfigurable intelligent surface for signal enhancement in millimeter wave

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Science china(Technological Sciences) 2024年第4期67卷 1133-1138页

作者： YAO HuiMing DU XinRun WANG HengBin GAO Song PANG YaChen zheng HaiRong GONG HuiWen LI Yi xu JianChun ZHANG JianHua BI Ke State Key Laboratory of Information Photonics and Optical Communications School of ScienceBeijing University of Posts and TelecommunicationsBeijing 100876China Beijing Key Laboratory of Intelligent Telecommunications Software and Multimedia Beijing University of Posts and TelecommunicationsBeijing 100876China State Key Laboratory of Networking and Switching Technology Beijing University of Posts and TelecommunicationsBeijing 100876China

Millimeter wave with large bandwidth,high transmission rate,and low delay is considered a reliable alternative to cope with the spectrum ***,the fast attenuation and narrow beam characteristics make it difficult to achieve long-distance or wide-range ***,a 1-bit dual-band reflective reconfigurable intelligent surface(RIS)for signal enhancement in millimeter wave with 16×16 elements is designed,fabricated,and *** from most existent RIS,dynamic programming is realized at two separate frequency bands by integrating the PIN diodes and field-programmable gate array(FPGA).Particularly,the beam deflection,dual-beam,and multi-beam are created based on the coding theory and convolution operation,proving the effectiveness of wavefront ***,the far-field patterns and signal power with different coding sequences are measured and *** is indicated that the received signal power is 6–7 dB stronger than that without coding,which shows good agreement with the desired *** proposed reconfigurable metasurface exhibits great potential in beam forming,making it a promising candidate for progressive wireless communication applications.

关键词： dual-band millimeter wave reconfigurable intelligent surface signal enhancement

MODEL AND PERFORMANCE ANALYSIS OF FMT SYSTEM AND ORTHOGONAL FILTERBANKS

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Journal of Electronics(china) 2009年第1期26卷 80-87页

作者： xu xiaorong {2. baoyu Wang Lei institute of signal {2. and transmission Nanjing University of Posts and Telecommunications Nanjing 210003 China

An orthogonal multi-carrier modulation-Filtered Multi-Tone (FMT) modulation, is evaluated in this paper. The objective of this paper is to model the FMT system with polyphase fil- terbank network, design its synthesis/analysis orthogonal filterbanks and analyze their performance. Oversampled and critically sampled cases of FMT system are discussed in detail. Perfect Reconstruc- tion (PR) properties of M parallel orthogonal subchannels in the case of critically sampled is derived from filterbank polyphase decomposition. Diverse types of prototype filters which include Infinite Impulse Response (IIR) and Finite Impulse Response (FIR) are designed and analyzed. Performance analysis of orthogonal filterbanks which are implemented by these prototype filters are proposed and compared respectively. Simulation results of FMT orthogonal filterbanks are presented. In the end, the application prospect of FMT is discussed.

关键词： Filtered Multi-Tone (FMT) System modeling Orthogonal filterbanks Prototype filter Performance analysis

OPTIMAL POWER ALLOCATION WITH AF AND SDF STRATEGIES IN DUAL-HOP COOPERATIVE MIMO NETWORKS

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Journal of Electronics(china) 2010年第3期27卷 328-339页

作者： xu xiaorong {2. baoyu Zhang Jianwu institute of signal {2. and transmission Nanjing University of Posts and Telecommunications Nanjing 210003 China College of Telecommunication Engineering Hangzhou Dianzi University Hangzhou 310018 China

Dual-hop cooperative Multiple-Input Multiple-Output (MIMO) network with multi-relay cooperative communication is introduced. Power allocation problem with Amplify-and-Forward (AF) and Selective Decode-and-Forward (SDF) strategies in multi-node scenario are formulated and solved respectively. Optimal power allocation schemes that maximize system capacity with AF strategy are presented. In addition, optimal power allocation methods that minimize asymptotic Symbol Error Rate (SER) with SDF cooperative protocol in multi-node scenario are also proposed. Furthermore, performance comparisons are provided in terms of system capacity and approximate SER. Numerical and simulation results confirm our theoretical analysis. It is revealed that, maximum system capacity could be obtained when powers are allocated optimally with AF protocol, while minimization of system's SER could also be achieved with optimum power allocation in SDF strategy. In multi-node scenario, those optimal power allocation algorithms are superior to conventional equal power allocation schemes.

关键词： Dual-hop cooperative Multiple-Input Multiple-Output (MIMO) network Optimal power allocation Amplify-and-Forward (AF) Selective Decode-and-Forward (SDF) System capacity Asymptotic Symbol Error Rate (SER)