检索结果-内蒙古大学图书馆

joint precoding for RIS-Assisted Wideband THz Cell-Free Massive MIMO Systems

IEEE INTERNET OF THINGS JOURNAL 2024年第20期11卷 33361-33370页

作者： Su, Xin He, Ruisi Zhang, Peng Ai, Bo Beijing Jiaotong Univ Sch Elect & Informat Engn Beijing 100044 Peoples R China

Reconfigurable intelligent surface (RIS)-aided terahertz (THz) cell-free massive multiple-input-multiple-output (mMIMO) networks have been envisioned as a prospective technology for future 6G networks. However, due to the ultrawide bandwidth and the frequency-dependent characteristics of RISs, beam-split effect has become an unavoidable obstacle. To compensate the severe performance degradation caused by beam split effect, we introduce additional time delay (TD) layers at both access points (APs) and RISs. Accordingly, we propose a joint precoding framework at APs and RISs to fully unleash the potential of the considered network. Specifically, we first formulate the joint precoding as a nonconvex optimization problem. Then, given the location of unchanged RISs, we adjust the TDs of APs to align the generated beams toward RISs. After that, with knowledge of the optimal TDs of APs, we decouple the optimization problem into three subproblems of optimizing the baseband beamformers, RISs and TDs of RISs, respectively. Exploiting multidimensional complex quadratic transform, we transform the subproblems into convex forms and solve them under alternate optimizing framework. Numerical results verify that the proposed method can effectively mitigate beam split effect and significantly improve the achievable rate compared with conventional cell-free mMIMO networks.

关键词： precoding Terahertz communications Radio frequency Array signal processing Vectors Reconfigurable intelligent surfaces Optimization Cell-free massive multiple-input-multiple-output (mMIMO) joint precoding reconfigurable intelligent surface (RIS) terahertz (THz)

来源：评论

学校读者我要写书评

暂无评论

joint precoding with Flexible Power Constraints in Multibeam Satellite Systems

Joint Precoding with Flexible Power Constraints in Multibeam...

引用

54th Annual IEEE Global Telecommunications Conference (GLOBECOM)

作者： Chatzinotas, Symeon Zheng, Gan Ottersten, Bjoern Univ Luxembourg SnT Securityandtrust Lu Luxembourg Luxembourg

ISBN: (纸本)9781424492688

In conventional multibeam satellite systems, frequency and polarization orthogonalization have been traditionally employed for mitigating interbeam interference. However, the paradigm of multibeam joint precoding allows for full frequency reuse while assisting beam-edge users. In this paper, the performance of linear beamforming is investigated in terms of meeting traffic demands. More importantly, generic linear constraints are considered over the transmit covariance matrix in order to model the power pooling effect which can be implemented through flexible traveling wave tube amplifiers (TWTAS) or multiport amplifiers. The performance of this scheme is compared against conventional spotbeam systems based on the rate-balancing objective. In this context, it is shown that significantly higher spectral efficiency can be achieved through beamforming, while flexible power constraint offers better rate-balancing.

关键词： Array signal processing Context joints Rain fading Satellite broadcasting Satellites TWTAS artificial satellites beam-edge users conventional spotbeam systems covariance matrices covariance matrix flexible power constraints flexible travelling wave tube amplifiers joint precoding multibeam satellite systems multiport amplifiers polarization orthogonalization precoding rate-balancing objective telecommunication traffic traffic demands travelling wave amplifiers

来源：评论

学校读者我要写书评

暂无评论

A joint precoding Framework for Wideband Reconfigurable Intelligent Surface-Aided Cell-Free Network

引用

IEEE TRANSACTIONS ON SIGNAL PROCESSING 2021年 69卷 4085-4101页

作者： Zhang, Zijian Dai, Linglong Tsinghua Univ Beijing Natl Res Ctr Informat Sci & Technol BNRis Beijing 100084 Peoples R China Tsinghua Univ Dept Elect Engn Beijing 100084 Peoples R China

Thanks to the strong ability against the inter-cell interference, cell-free network is considered as a promising technique to improve network capacity. However, further capacity improvement requires to deploy more base stations (BSs) with high cost and power consumption. To address this issue, inspired by the recently developed reconfigurable intelligent surface (RIS) technique, we propose the concept of RIS-aided cell-free network to improve the capacity with low cost and power consumption. The key idea is to replace some of the required BSs by low-cost and energy-efficient RISs. Then, in a wideband RIS-aided cell-free network, we formulate the problem of joint precoding design at BSs and RISs to maximize the network capacity. Due to the non-convexity and high complexity of the formulated problem, we develop an alternating optimization framework to solve this challenging problem. In particular, we decouple this problem via fractional programming, and solve the subproblems alternatively. Note that most of the scenarios considered in existing works are special cases of the general scenario studied in this paper, and the proposed joint precoding framework can serve as a general solution to maximize the capacity in most existing RIS-aided scenarios. Finally, simulation results demonstrate that, compared with the conventional cell-free network, the network capacity under the proposed scheme can be improved significantly.

关键词： Measurement Power demand precoding Simulation Reconfigurable intelligent surfaces Programming Energy efficiency Cell-free network reconfigurable intelligent surface (RIS) wideband joint precoding

来源：评论

学校读者我要写书评

暂无评论

A Limited Feedback joint precoding for Amplify-and-Forward Relaying

引用

IEEE TRANSACTIONS ON SIGNAL PROCESSING 2010年第3期58卷 1347-1357页

作者： Huang, Yongming Yang, Luxi Bengtsson, Mats Ottersten, Bjorn Southeast Univ Sch Informat Sci & Engn Nanjing 210096 Peoples R China Royal Inst Technol ACCESS Linnaeus Ctr KTH Signal Proc Lab SE-10044 Stockholm Sweden Univ Luxembourg Luxembourg Luxembourg

This paper deals with the practical precoding design for a dual hop downlink with multiple-input multiple-output (MIMO) amplify-and-forward relaying. First, assuming that full channel state information (CSI) of the two hop channels is available, a suboptimal dual hop joint precoding scheme, i.e., precoding at both the base station and relay station, is investigated. Based on its structure, a scheme of limited feedback joint precoding using joint codebooks is then proposed, which uses a distributed codeword selection to concurrently choose two joint precoders such that the feedback delay is considerably decreased. Finally, the joint codebook design for the limited feedback joint precoding system is analyzed, and results reveal that independent codebook designs at the base station and relay station using the conventional Grassmannian subspace packing method is able to guarantee that the overall performance of the dual hop joint precoding scheme improves with the size of each of the two codebooks. Simulation results show that the proposed dual hop joint precoding system using distributed codeword selection scheme exhibits a rate or BER performance close to the one using the optimal centralized codeword selection scheme, while having lower computational complexity and shorter feedback delay.

关键词： Amplify-and-forward relaying dual hop Grassmannian codebook joint precoding limited feedback multiple-input multiple-output

来源：评论

学校读者我要写书评

暂无评论

A Limited Feedback joint precoding for Dual-Hop MIMO Amplify-and-Forward Relay Systems

引用

IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2013年第8期62卷 4125-4130页

作者： Wang, Haihong Ghogho, Mounir Cheng, Wenjing Wang, Xin Wei, Jibo Natl Univ Def Technol Sch Elect Sci & Engn Changsha 410073 Hunan Peoples R China Univ Leeds Leeds LS2 9JT W Yorkshire England Int Univ Rabat Sala El Jadida 10100 Morocco

This paper investigates the limited feedback joint precoding design for dual-hopmultiple-input-multiple-output (MIMO) amplify-and-forward (AF) relay systems. Assuming that full channel state information (CSI) of two hops is available and that a linear receiver is employed at the destination, a suboptimal joint precoding structure, which is based on the maximization of the minimum postprocessing signal-to-noise ratio (SNR), is presented. Based on a derived lower bound on the minimum postprocessing SNR, a joint codeword selection (JCS) scheme at the destination is proposed. To reduce feedback latency and computational complexity, the lemma of singular value inequalities of a product matrix and other lemmas are used to split the JCS into two independent codeword selections (ICSs). Thus, the codeword selections at the relay and the destination are concurrently carried out. Simulation results illustrate the effectiveness of the proposed limited feedback joint precoding design. They also show that the ICS scheme displays a bit error rate performance that is close to that of the joint scheme, while having shorter feedback latency and lower computational complexity.

关键词： Amplify-and-forward (AF) relay dual hop joint precoding limited feedback multiple-input-multiple-output (MIMO)

来源：评论

学校读者我要写书评

暂无评论

Robust joint precoding Design in MIMO Cooperative Systems

Robust Joint Precoding Design in MIMO Cooperative Systems

引用

2011 13th IEEE joint International Computer Science and Information Technology Conference(JICSIT 2011)

作者： Xiaoguang Li Industrial & Commercial College Hebei University Baoding China

A joint precoding design is proposed for MIMO cooperative systems where channel estimation error exists. Considering the effect of channel estimation error on the performance of systems, the proposed method utilizes MMSE criterion to design precoding at source node and relay node which is robust to channel estimation error. Theory and simulation show that the proposed method reduces the bad effect brought by channel estimation error, and it has much lower complexity.

关键词： MIMO cooperative channel estimation error joint precoding

来源：评论

学校读者我要写书评

暂无评论

joint Active precoding for RIS-aided Cell-free MIMO Networks 12

Joint Active Precoding for RIS-aided Cell-free MIMO Networks

引用

12th IFIP/IEEE International Conference on Performance Evaluation and Modeling in Wired and Wireless Networks (PEMWN)

作者： Dogim, Ghadir Maher, Engy Aly El-Mahdy, Ahmed Dressler, Falko German Univ Cairo Cairo Egypt TU Berlin Berlin Germany

ISBN: (纸本)9783903176607

In the future communications, cell-free networks are considered very promising, owing to their robustness against inter-cell interference which degrades the user signal-to-interference-plus-noise-ratio (SINR). For an efficient network to achieve an enhanced capacity at a minimized power consumption, reconfigurable intelligent surfaces (RIS) are promoted as a key candidate 6G technology. In this paper, a joint precoding RIS aided cell-free Multiple-Input-Multiple-Output (MIMO) network is considered, where a weighted sum rate (WSR) maximization problem is formulated and decoupled into subproblems. A feasible solution is then obtained using fractional programming (FP). Finally, the performance of passive RIS and active RIS is then compared.

关键词： Cell-free MIMO Reconfigurable intelligent surfaces Active-RIS joint precoding Multiplicative fading Fractional Programing Quadratic constraint quadratic programming

来源：评论

学校读者我要写书评

暂无评论

joint Source and Relay precoding in Multiantenna Millimeter-Wave Systems

引用

IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2017年第6期66卷 4924-4937页

作者： Xue, Xuan Wang, Yongchao Wang, Xianbin Bogale, Tadilo Endeshaw Xidian Univ Sch Telecommun Engn State Key Lab Integrated Serv Network Xian 710071 Peoples R China Western Univ Dept Elect & Comp Engn London ON N6A 3K7 Canada

This paper considers the joint source and relay precoding design for millimeter-wave (mm-wave) systems under the assumption that the source, relay, and destination nodes are equipped with multiple antennas. We focus on the rate maximization problem with the per antenna power constraints at the source and relay while taking into account the computational complexity and sparse characteristics of mm-wave channels. We solve this problem as follows. First, the precoding problem is formulated by exploiting the sparse and low-rank structures of mm-wave channels which is nonconvex. Second, we reformulate this nonconvex problem into two semidefinite programming (SDP) subproblems, each having a rank one constraint. Third, we propose two algorithms to solve these two SDP subproblems: interior-point-based and low complexity algorithms. Finally, the original rate maximization problem is examined by iteratively utilizing the solutions of these SDP problems. The proposed interior-point-based method to solve the SDP problem uses the standard convex optimization tools followed by the random vector generation scheme to get the rank one solution. However, the proposed low complexity algorithm examines the SDP problem in one-dimensional spatial signal space (i.e., without rank relaxation) via a new augmented Lagrangian function method. Simulation results show that both algorithms achieve good performances, and the latter one is much faster than the former one with a slight decrease in performance. In addition, both algorithms achieve superior performances compared to the existing precoding design algorithms.

关键词： joint precoding large-scale antennas millimeter-wave system (mm-wave) relay beamforming source precoding

来源：评论

学校读者我要写书评

暂无评论

joint optimization of source and relay precoding for AF MIMO relay systems

引用

EURASIP JOURNAL ON WIRELESS COMMUNICATIONS AND NETWORKING 2015年第1期2015卷 1页

作者： Li, Jun Jiang, Xueqin Song, Sangseob Guo, Ying Lee, Moon Ho Chonbuk Natl Univ Dept Elect & Informat Engn Jeonju South Korea Donghua Univ Sch Informat Sci & Technol Shanghai Peoples R China Cent South Univ Sch Informat Sci & Engn Changsha Hunan Peoples R China

In this paper, we investigate a joint source and relay precoding design scheme for an amplify-and-forward (AF) multiple-input multiple-output (MIMO) relay system with absence of the direct link. The joint optimization problem, which is to minimize an objective function based on the mean square error (MSE), is formulated as a nonconvex optimization problem in the AF MIMO relay system. Instead of the conventional iterative method, we use an inequality to derive a lower bound of the MSE under the power constraint for obtaining a suboptimal solution of the objective function, which makes the optimization problem convex and also approaches the existing upper bound of the MSE, especially at the high signal-to-noise ratio (SNR). Numerical results show that this scheme outperforms the previous schemes in terms of either MSE or bit error rate (BER).

关键词： Amplify-and-forward (AF) multiple-input multiple-output (MIMO) relay joint precoding Lower bound

来源：评论

学校读者我要写书评

暂无评论

precoding for joint Spectral Sidelobes Suppression and PAPR Reduction in OFDM System 9

Precoding for Joint Spectral Sidelobes Suppression and PAPR ...

引用

2017 9th IEEE International Conference on Communication Software and Networks (ICCSN 2017)

作者： Lei Wang Lei Zhang Renhui Xu Laixian Peng College of Communication Engineering PLA University of Science and Technology

ISBN: (纸本)9781509038237;9781509038220

In the scenario of multiple access communication, the spectral sidelobes and peak-to-average power radio(PAPR) problems of orthogonal frequency division multiplexing(OFDM) must not be ignored. This paper proposes a novel precoding scheme that ahead of inverse discrete Fourier transformation(IDFT) is presented to jointly suppress the inband-out-of-subband(IBOSB) radiation and high PAPR in orthogonal frequency division multiplexing access(OFDMA) systems. Its design is based on generalized eigenvalue problem. Finally, the results of simulations show that joint precoding scheme achieves the markedly performance of spectral sidelobes suppression and PAPR reduction.

关键词： OFDM precoding OOB radiation sidelobe suppression PAPR PAPR reduction joint precoding

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：