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mimo precoding and mode adaptation in femtocellular systems

EURASIP JOURNAL ON WIRELESS COMMUNICATIONS AND NETWORKING 2013年第1期2013卷 1页

作者： Jiang, Chenzi Cimini, Leonard J., Jr. Himayat, Nageen Univ Delaware Dept Elect & Comp Engn Newark DE 19716 USA Intel Corp Intel Labs Wireless Commun Lab Santa Clara CA USA

Hierarchical femtocellular architectures have become popular recently because of their potential to provide increased coverage and capacity in cellular systems. However, introduction of femtocells might reduce the overlay macrocellular system performance due to increased interference caused to macrocellular users. In this article, two mimo precoding techniques are considered at the femtocellular base stations (FBSs) to control the interference to the macrocellular users: precoding matrix index (PMI), and least interference (LI). With mimo precoding, the limited CSI at the transmitter is the index of the precoder chosen from the codebook fed back by the receiver. The LI technique can be employed at the FBSs to maximize the macrocellular throughput, but it also results in significant reduction in femtocellular throughput. The PMI approach can maximize the signal power at a desired receiver, with minimal feedback. In this article, we develop algorithms that adapt at the FBSs between the LI and PMI schemes to increase both the macrocellular and femtocellular throughputs. We show that allowing for mode adaptation at each FBS improves the system performance when compared with using the same mode across the system, and a simple binary choice at each FBS can nearly achieve the optimum mode-adaptation performance. Analysis and simulation results in a multicell environment are presented to illustrate the improvement in system performance with the proposed techniques.

关键词： mimo precoding Codebook Mode adaptation Interference Throughput Femtocell Macrocell

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An SVD Processor Based on Golub-Reinsch Algorithm for mimo precoding With Adjustable Precision

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS I-REGULAR PAPERS 2019年第7期66卷 2572-2583页

作者： Wu, Chun-Hun Tsai, Pei-Yun Realtek Hsinchu 300 Taiwan Natl Cent Univ Dept Elect Engn Taoyuan 32001 Taiwan

A singular-value-decomposition (SVD) processor having adjustable precision for 8 x 8 multiple-input multiple-output precoding systems supporting up to 256-quadrature amplitude modulation (QAM) is designed and implemented. The memory-based architecture that consists of eight processing elements, each having two coordinate rotation digital computer modules, is employed. Golub-Reinsch SVD (GR-SVD) algorithm with Rayleigh quotient shift is used. Thus, two-phase operations are performed including bidiagonalization and implicit shifted QR for diagonalization. The split, deflation, and shift techniques of GR-SVD are helpful to accelerate the diagonalization and reduce the computation complexity. To cover the precision requirements for compact 256-QAM constellation and spatially correlated channels, hybrid datapath representations are used. The threshold for split and deflation can be adjusted and thus the precision of the SVD processor is variable according to the requirements. Although the high precision results in a large gate count, this SVD processor in 40-nm CMOS technology can complete the decomposition of an 8 x 8 matrix in 313 clock cycles averagely and is able to provide a throughput rate of 591K matrix/s with good power efficiency.

关键词： SVD Golub-Reinsch SVD bidiagonalization mimo precoding CORDIC

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Joint MU-mimo precoding and Computation Optimization for Energy Efficient Industrial IoT With Mobile Edge Computing

IEEE TRANSACTIONS ON GREEN COMMUNICATIONS AND NETWORKING

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IEEE TRANSACTIONS ON GREEN COMMUNICATIONS AND NETWORKING 2023年第3期7卷 1472-1485页

作者： Su, Na Wang, Jun-Bo Chen, Yijian Yu, Hongkang Ding, Changfeng Pan, Yijin Wang, Jiangzhou Southeast Univ Natl Mobile Commun Res Lab Nanjing 210096 Peoples R China State Key Lab Mobile Network & Mobile Multimedia T Shenzhen 518055 Peoples R China ZTE Corp Wireless Res Inst Shenzhen 518055 Peoples R China ZTE Corp Wireless Res Inst Beijing 100029 Peoples R China Nanjing Univ Posts & Telecommun Coll Telecommun & Informat Engn Nanjing 210003 Peoples R China Univ Kent Sch Engn Canterbury CT2 7NT England

In the fourth industrial revolution, the industrial Internet of Things (IIoT) will bring fundamental changes to human communities. This paper proposes to make full use of the under-utilized computing resources of wired edge devices to alleviate the computing burden of the processing center in delay-constrained multi-user networks. Our goal is to minimize the weighted energy consumption while ensuring the required latency. The formulated problems are NP-hard involving joint optimization of the computation task assignment, transmit association design, multiple-input multiple-output (mimo) precoding, and computing resource allocation with binary and partial offloading protocols. By utilizing the weighted minimum mean-squared-error method, quadratic transformation, and difference of convex functions algorithm, we propose two joint computation offloading and resource allocation algorithms for binary and partial offloading protocols, respectively. Simulation results confirm the efficiency of the proposed algorithms and demonstrate that the proposed algorithms achieve a significant computation performance enhancement.

关键词： IIoT mobile edge computing wired edge devices mimo precoding computation offloading

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Joint mimo precoding and Computation Resource Allocation for Dual-Function Radar and Communication Systems With Mobile Edge Computing

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IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS 2022年第7期40卷 2085-2102页

作者： Ding, Changfeng Wang, Jun-Bo Zhang, Hua Lin, Min Li, Geoffrey Ye Southeast Univ Natl Mobile Commun Res Lab Nanjing 211111 Peoples R China Nanjing Univ Posts & Telecommun Coll Telecommun & Informat Engn Nanjing 210003 Peoples R China Imperial Coll London Dept Elect & Elect Engn London SW7 2AZ England

In this paper, an integrated communication, radar sensing, and mobile-edge computing (CRMEC) architecture is developed, where user terminals (UTs) perform radar sensing and computation offloading simultaneously at the same spectrum by using multiple-input and multiple-output (mimo) arrays and dual-function radar-communication techniques. We formulate a multi-objective optimization problem to jointly consider the performance of multi-UT mimo radar beampattern design and computation offloading energy consumption while jointly optimizing individual transmit precoding for radar and communication and computation resource allocation. To address the optimization problem, we first decompose the it into three subproblems and adopt an iterative optimization algorithm. Specifically, quadratic transform based fractional programming methods are used to minimize the offloading energy consumption. The design objective of mimo radar beampattern is handled by the first-order Taylor expansion. Transmit precoding is designed to optimize radar sensing and computation task offloading. The local and edge computation resource allocation are obtained in closed-form. Numerical results verify the effectiveness of the proposed algorithms. The proposed CRMEC architecture can generate the desired multi-UT mimo radar beampattern and perform computation offloading simultaneously.

关键词： Radar Sensors Robot sensing systems precoding Radar signal processing Communication symbols Resource management Dual function radar and communication mobile edge computing mimo precoding radar sensing

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Satellite-Terrestrial Assisted Multi-Tier Computing Networks With mimo precoding and Computation Optimization

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2024年第4期23卷 3763-3779页

作者： Ding, Changfeng Wang, Jun-Bo Chen, Yijian Yu, Hongkang Cheng, Ming Lin, Min Wang, Jiangzhou Nanjing Univ Posts & Telecommun Sch Commun & Informat Engn Nanjing 210003 Peoples R China Southeast Univ Natl Mobile Commun Res Lab Nanjing 211111 Peoples R China State Key Lab Mobile Network & Mobile Multimedia T Shenzhen 518055 Peoples R China ZTE Corp Wireless Res Inst Shenzhen 518055 Peoples R China Univ Kent Sch Engn Canterbury CT2 7NZ Kent England

In this paper, satellite-terrestrial assisted multi-tier computing networks (STMTCN) are proposed to satisfy the growing computation demands of user terminals (UTs) in next generation wireless networks. In the STMTCN, UT's computation task can be processed at different computing entities and a multi-tier computation model named computing depth is proposed to better reflect the multi-tier computing process. Then, we formulate a weighted sum energy consumption minimization problem via jointly optimizing UT-satellite association, computing depth, multiple-input multiple-out (mimo) precoding, and computation resource allocation. The non-convex optimization problem is decomposed into four subproblems, each of which is solved iteratively. Specifically, the UT-satellite association subproblem is solved by quadratic transform based fractional programming and Lagrangian dual method and a closed-form expression is obtained. The computing depth for local tier and the satellite tier is solved respectively with first-order Taylor expansion. Then, mimo precoding subproblem for UT and satellite offloading is solved by quadratic transform and interior point method (IPM). Finally, the computation resource allocation for UT and satellite is obtained in a closed-form expression and the GW computation resource allocation is solved by using IPM. Simulation results show that the proposed STMTCN and algorithms can fulfill the UT's computing demands with low energy consumption.

关键词： Multi-tier mobile edge computing computing depth mimo precoding LEO satellite resource allocation

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A mimo precoding Based Physical Layer Security Technique for Key Exchange Encryption 81

A MIMO Precoding Based Physical Layer Security Technique for...

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81st IEEE Vehicular Technology Conference (VTC Spring)

作者： Taha, Hasan Alsusa, Emad Univ Manchester Sch Elect & Elect Engn Microwave & Commun Syst MACS Grp Manchester M13 9PL Lancs England

ISBN: (纸本)9781479980888

Secret key establishment is considered to be one of the main challenging issues in cryptography. Many security algorithms are implemented in practice using complicated mathematical methods to exchange secret keys, but those methods are not desirable in power limited terminals such as cellular and sensor networks. In this paper, we propose a physical layer method for exchanging secret key bits in precoding based multi-input multi-output (mimo) orthogonal frequency division multiplexing (OFDM) systems. The proposed method uniquely relates the key bits to the indices of the precoding matrix used for mimo channel precoding. The basic idea of the technique is to utilize a mimo-OFDM precoding codebook. Comparative analysis with respect to the average number of mismatch bits, named key error rate (KER), shows an interesting lead for the new method relative to existing work. In addition, it will be shown that the proposed technique requires lower computation per byte per secret key.

关键词： Physical layer security mimo precoding OFDM

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Optimal Lattices for mimo precoding

Optimal Lattices for MIMO Precoding

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IEEE International Symposium on Information Theory (ISIT)

作者： Kapetanovic, Dzevdan Cheng, Hei Victor Mow, Wai Ho Rusek, Fredrik Lund Univ Elect & Informat Technol Dept S-22100 Lund Sweden Hong Kong Univ Sci & Technol Dept Comp & Elect Engn Kowloon Hong Kong Peoples R China

ISBN: (纸本)9781457705953

Consider the communication model (y) over bar = H F (x) over bar + (n) over bar, where H;F are real-valued matrices, (x) over bar is a data vector drawn from some real-valued lattice (e.g. M-PAM), (n) over bar is additive white Gaussian noise and (y) over bar is the received vector. It is assumed that the transmitter and the receiver have perfect knowledge of the channel matrix H (perfect CSI) and that the transmitted signal F (x) over bar is subject to an average energy constraint. The columns of the matrix H F can be viewed as basis vectors that span a lattice, and we are interested in the minimum distance of this lattice. More precisely, for a given H, which F under an average energy constraint will maximize the minimum distance of the lattice H F ? This particular question remains open within the theory of lattices. This work provides the solution for 2 x 2 matrices H;F. The answer is an F such that H F is a hexagonal lattice.

关键词： AWGN Constellation diagram Covariance matrix Generators Lattices mimo mimo communication mimo precoding Matrix decomposition Optimization additive white Gaussian noise channel matrix data vector drawn energy constraint hexagonal lattice lattice theory lattice theory optimal lattice precoding radio receivers radio transmitters real-valued matrix signal transmission wireless channels

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Investigating the Effects of Channel Estimation Errors in mmWave mimo precoding Systems 11

Investigating the Effects of Channel Estimation Errors in mm...

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IEEE 11th International Conference on Communication Software and Networks (ICCSN)

作者： Zeb, Arsalan Li, Feng Xi An Jiao Tong Univ Sch Elect & Informat Engn Xian 710049 Shaanxi Peoples R China

ISBN: (纸本)9781728121840

Channel state information (CSI) can be obtained via various channel estimation techniques. However, in practical scenarios, it is always difficult to achieve perfect channel information due to the presence of channel estimation errors (CEE), quantization errors, and hardware mismatch problems, making it difficult to realize the desired system performance. To the best of our knowledge, this is the first report on the investigation of spectral efficiency of millimeter wave (mmWave) precoding system, considering the practical case of imperfect CSI. Gaussian random noise is exploited to realize the presence of CEE. Later on, its effect on the spectral efficiency of mmWave cellular system is investigated for different known variance of the errors. Simulation results from both perfect and imperfect CSI are compared and evaluated which shows the performance degradation of mmWave cellular system.

关键词： Millimeter-wave (mmWave) communication mimo precoding channel estimation errors imperfect CSI

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Full-Rate Full-Diversity Achieving mimo precoding with Partial CSIT

Full-Rate Full-Diversity Achieving MIMO Precoding with Parti...

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IEEE Wireless Communications and Networking Conference (WCNC)

作者： Dutta, Biswajit Barik, Somsubhra Chockalingam, A. Indian Inst Sci Dept ECE Bangalore 560012 Karnataka India

ISBN: (纸本)9781612842547

In this paper, we consider a slow-fading n(t) x n(r) multiple-input multiple-output (mimo) channel subjected to block fading. Reliability (in terms of achieved diversity order) and rate (in number of symbols transmitted per channel use) are of interest in such channels. We propose a new precoding scheme which achieves both full diversity (n(t)n(r)th order diversity) as well as full rate (n(t) symbols per channel use) using partial channel state information at the transmitter (CSIT). The proposed scheme achieves full diversity and improved coding gain through an optimization over the choice of constellation sets. The optimization maximizes d(min)(2) for our precoding scheme subject to an energy constraint. The scheme requires feedback of n(t)(-1) angle parameter values, compared to 2n(t)n(r) real coefficients in case of full CSIT. Further, for the case of n(t) x 1 system, we prove that the capacity achieved by the proposed scheme is same as that achieved with full CSIT. Error rate performance results for n(t) = 3, 4, 8 show that the proposed scheme performs better than other precoding schemes in the literature;the better performance is due to the choice of the signal sets and the feedback angles in the proposed scheme.

关键词： mimo precoding constellation sets full-diversity full-rate partial CSIT

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Multi-mode Sorted QR Decomposition for 4x4 and 8x8 Single-user/Multi-user mimo precoding

Multi-mode Sorted QR Decomposition for 4x4 and 8x8 Single-us...

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IEEE International Symposium on Circuits and Systems (ISCAS)

作者： Chen, Chi-Mao Lin, Chih-Hsiang Tsai, Pei-Yun Natl Cent Univ Dept Elect Engn Jhongli Taiwan

ISBN: (纸本)9781479983919

This paper presents a configurable multi-mode QR decomposition (QRD) processor. It supports 4x4 and 8x8 QRD with multi-layer sorting for single-user mimo precoding. Besides, it can perform block-based sorting for multi-user mimo precoding. Both forward mode for decomposition and backward mode for signal precoding are provided. This QRD processor is designed in pipelined systolic array. An in-place strategy with pointer-based control mechanism is proposed for sorting buffers, which reduces 42.3% D flip-flops. The proposed processor implemented in 90nm CMOS technology can generate 9.45MQRD/s for decomposing 8x8 channel matrix with sorting, and outperforms the related works in terms of throughput and hardware efficiency.

关键词： mimo precoding multi-user mimo QR decomposition sorting systolic array

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