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Joint Beamforming Design for Dual-Functional Radar-Communication Systems Under Beampattern Gain Constraints
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作者 CHEN Guangyi ZHANG Ruoyu +2 位作者 REN Hong LIN Xu WU Wen 《ZTE Communications》 2024年第3期13-20,共8页
The joint beamforming design challenge for dual-functional radar-communication systems is addressed in this paper.The base station in these systems is tasked with simultaneously sending shared signals for both multi-u... The joint beamforming design challenge for dual-functional radar-communication systems is addressed in this paper.The base station in these systems is tasked with simultaneously sending shared signals for both multi-user communication and target sensing.The primary objective is to maximize the sum rate of multi-user communication,while also ensuring sufficient beampattern gain at particular angles that are of interest for sensing,all within the constraints of the transmit power budget.To tackle this complex non-convex problem,an effective algorithm that iteratively optimizes the joint beamformers is developed.This algorithm leverages the techniques of fractional programming and semidefinite relaxation to achieve its goals.The numerical results confirm the effectiveness of the proposed algorithm. 展开更多
关键词 dual-functional radar-communication joint beamforming design beampattern gain constraints semidefinite relaxation fractional programming
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Joint Beamforming Optimization for Reconfigurable Intelligent Surface-Enabled MISO-OFDM Systems 被引量:9
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作者 Keming Feng Xiao Li +1 位作者 Yu Han Yijian Chen 《China Communications》 SCIE CSCD 2021年第3期63-79,共17页
In this paper,we investigate the reconfigurable intelligent surface(RIS)-enabled multiple-input-single-output orthogonal frequency division multiplexing(MISO-OFDM)system under frequency-selective channels,and propose ... In this paper,we investigate the reconfigurable intelligent surface(RIS)-enabled multiple-input-single-output orthogonal frequency division multiplexing(MISO-OFDM)system under frequency-selective channels,and propose a low-complexity alternating optimization(AO)based joint beamforming and RIS phase shifts optimization algorithm to maximize the achievable rate.First,with fixed RIS phase shifts,we devise the optimal closedform transmit beamforming vectors corresponding to different subcarriers.Then,with given active beamforming vectors,near-optimal RIS reflection coefficients can be determined efficiently leveraging fractional programming(FP)combined with manifold optimization(MO)or majorization-minimization(MM)framework.Additionally,we also propose a heuristic RIS phase shifts design approach based on the sum of subcarrier gain maximization(SSGM)criterion requiring lower complexity.Numerical results indicate that the proposed MO/MM algorithm can achieve almost the same rate as the upper bound achieved by the semidefinite relaxation(SDR)algorithm,and the proposed SSGM based scheme is only slightly inferior to the upper bound while has much lower complexity.These results demonstrate the effectiveness of the proposed algorithms. 展开更多
关键词 reconfigurable intelligent surface(RIS) OFDM joint beamforming optimization fractional programming majorization-minimization manifold optimization
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Joint Active and Passive Beamforming Design for Hybrid RIS-Aided Integrated Sensing and Communication
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作者 Chu Hongyun Yang Mengyao +1 位作者 Pan Xue Xiao Ge 《China Communications》 SCIE CSCD 2024年第10期101-112,共12页
Integrated sensing and communication(ISAC) is considered an effective technique to solve spectrum congestion in the future. In this paper, we consider a hybrid reconfigurable intelligent surface(RIS)-assisted downlink... Integrated sensing and communication(ISAC) is considered an effective technique to solve spectrum congestion in the future. In this paper, we consider a hybrid reconfigurable intelligent surface(RIS)-assisted downlink ISAC system that simultaneously serves multiple single-antenna communication users and senses multiple targets. Hybrid RIS differs from fully passive RIS in that it is composed of both active and passive elements, with the active elements having the effect of amplifying the signal in addition to phase-shifting. We maximize the achievable sum rate of communication users by collaboratively improving the beamforming matrix at the dual function base station(DFBS) and the phase-shifting matrix of the hybrid RIS, subject to the transmit power constraint at the DFBS, the signal-to-interference-plus-noise-ratio(SINR) constraint of the radar echo signal and the RIS constraint are satisfied at the same time. The builtin RIS-assisted ISAC design problem model is significantly non-convex due to the fractional objective function of this optimization problem and the coupling of the optimization variables in the objective function and constraints. As a result, we provide an effective alternating optimization approach based on fractional programming(FP) with block coordinate descent(BCD)to solve the optimization variables. Results from simulations show that the hybrid RIS-assisted ISAC system outperforms the other benchmark solutions. 展开更多
关键词 alternating optimization fractional programming hybrid reconfigurable intelligent surface integrated sensing and communication joint active and passive beamforming
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Joint Beamforming for Delay Optimal Transmission in Cache-Enabled Wireless Backhaul Networks
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作者 Lingya Liu Cunqing Hua +1 位作者 Jinsong Yu Jing Xu 《Journal of Communications and Information Networks》 EI CSCD 2023年第2期141-154,共14页
This paper considers the problem of joint beamformer design for a two-tier wireless network,whereby a set of cache-enabled access points(APs)are connected to the base station(BS)via wireless backhaul links.The APs can... This paper considers the problem of joint beamformer design for a two-tier wireless network,whereby a set of cache-enabled access points(APs)are connected to the base station(BS)via wireless backhaul links.The APs can prefetch and store the files requested by users,to serve users directly in the access links.Thus low-latency transmissions are enabled as the transmission in the backhaul links is saved.However,due to the limited cache capacity,not all requested files can be stored in the APs,some of the non-cached APs then should be utilized as long as their transmission delays in the access and backhaul links can be well addressed.Two delay optimal beamformer design(DOBD)problems are formulated to minimize the overall delay incurred in the backhaul and access link transmissions via a joint optimization of the beamformer at the BS and APs.We consider the DOBD problem under non-fragment and fragment caching policies,both involving nonconvex link rate constraints.The semi-definite relaxation(SDR)and sequential convex approximation(SCA)schemes are adopted to approximate the nonconvex problems into convex ones,which are then iteratively solved.Numerical results demonstrate the convergence and improved transmission delay performance of the proposed scheme under various network settings. 展开更多
关键词 joint beamforming backhaul and access links delay optimal cache-enabled network
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An adaptive beamforming algorithm based on direction vector rotation and joint iterative optimization
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作者 XIE Jianping WANG Rui +1 位作者 HE Xiongxiong LI Sheng 《Chinese Journal of Acoustics》 CSCD 2017年第1期87-101,共15页
An adaptive beamforming algorithm named robust joint iterative optimizationdirection adaptive (RJIO-DA) is proposed for large-array scenarios. Based on the framework of minimum variance distortionless response (MVD... An adaptive beamforming algorithm named robust joint iterative optimizationdirection adaptive (RJIO-DA) is proposed for large-array scenarios. Based on the framework of minimum variance distortionless response (MVDR), the proposed algorithm jointly updates a transforming matrix and a reduced-rank filter. Each column of the transforming matrix is treated as an independent direction vector and updates the weight values of each dimension within a subspace. In addition, the direction vector rotation improves the performance of the algorithm by reducing the uncertainties due to the direction error. Simulation results show that the RJIO-DA algorithm has lower complexity and faster convergence than other conventional reduced-rank algorithms. 展开更多
关键词 SINR DA MVDR RLS An adaptive beamforming algorithm based on direction vector rotation and joint iterative optimization
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