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Efficient coding schemes with power allocation using space-time-frequency spreading

Journal of Systems Engineering and Electronics 2006年第2期17卷 263-267页

作者： Jiang Haining Luo Hanwen Tian Jifeng Song Wentao Liu Xingzhao Dept. of Electronic Engineering Mobile Communications Laboratory Shanghai Jiaotong Univ. Shanghai 200030 P. R. China

An efficient spaee-time-frequency （STF） coding strategy for multi-input multi-output orthogonal frequency division multiplexing （MIMO-OFDM） systems is presented for high bit rate data transmission over frequency selective fading channels. The proposed scheme is a new approach to space-time-frequency coded OFDM （ODFDM） that combines OFDM with space-time coding, linear precoding and adaptive power allocation to provide higher quality of transmission in terms of the bit error rate performance and power efficiency. In addition to exploiting the maximux diversity gain in frequency, time and space, the proposed scheme enjoys high coding advantages and low-complexity decoding. The significant performance improvement of our design is confirned by corroborating numerical simulations.

关键词： space-time-frequency linear precoding power allocation COFDM.

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High-rate space-time layered OFDM

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IEEE COMMUNICATIONS LETTERS 2002年第5期6卷 187-189页

作者： Xin, Y Giannakis, GB Univ Minnesota Dept Elect & Comp Engn Minneapolis MN 55455 USA

We derive a layered space-time scheme for multi-antenna orthogonal frequency-division multiplexed transmissions over frequency-selective channels. Compared with existing alternatives. the proposed scheme can attain very high spectral efficiency as well as improved performance. Enhanced diversity gains document its superior performance that is also tested by simulation.

关键词： BLAST frequency-selective channels linear precoding multi-antenna systems OFDM space-time coding

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Quantized Polar Transmitters for Power Efficient Massive MIMO Systems

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IEEE WIRELESS COMMUNICATIONS LETTERS 2021年第4期10卷 859-863页

作者： Xu, Guixian Lampu, Vesa Kosunen, Marko Stadius, Kari Ryynanen, Jussi Valkama, Mikko Anttila, Lauri Tampere Univ Dept Elect Engn Tampere 33720 Finland Aalto Univ Dept Elect & Nanoengn Sch Elect Engn Espoo 02150 Finland

This letter investigates the feasibility of the quantized digital polar transmitter architecture in a downlink multi-user massive multiple-input multiple-output orthogonal frequency-division multiplexing (MIMO-OFDM) system, where a low amplitude resolution and a moderate phase resolution are utilized. We derive a lower bound on the average sum-rate achievable with Gaussian signaling inputs and linear precoding by a simple diagonal approximation for the quantization distortion. The analysis and simulations demonstrate that the quantized polar transmitter can enable excellent performance in terms of average sum-rate throughput, symbol error rate (SER), and out-of-band (OOB) emission level, thus providing an attractive option for the traditional Cartesian architecture.

关键词： Massive MIMO OFDM linear precoding transmitter architectures polar transmitter power efficiency quantization

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MMSE transmitter design for correlated MIMO systems with imperfect channel estimates: Power allocation trade-offs

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2006年第8期5卷 2295-2304页

作者： Serbetli, Semih Yener, Aylin Philips Res NL-5656 AA Eindhoven Netherlands Penn State Univ Elect Engn Dept Wireless Commun & Networking Lab University Pk PA 16802 USA

We investigate the transmit precoder design problem for a multiple input multiple output (MIMO) link with correlated receive antennas, considering the effect of channel estimation. We work with the total. mean squared error (MSE) as the performance measure, and develop transceiver structures considering the effect of channel estimation and the correlation of the MIMO link. The proposed transceiver structures are optimum in the sense of minimizing the total MSE and distributing the total MSE equally among the parallel data streams. Motivated by the substantial effect the channel estimation process can have on the system performance, we next investigate the problem of how the correlated MIMO link should distribute its total available power between power expended for channel estimation versus data transmission. The optimum power allocation problem between the training sequences for-channel estimation and data transmission for the correlated MIMO link is shown to have a unique solution, that is different than the uncorrelated case. It is observed that the proposed transceiver achieves near-minimum MSE values via a relatively wide range of power allocation parameters. This is in contrast to the transceiver that is, oblivious to the estimation errors when a more precise power allocation strategy is needed to achieve the best performance. Our results demonstrate that the correlation structure of the MIMO link has a profound effect on the performance, and that the transceiver optimization should be done by taking both the correlation and the channel estimation process into account.

关键词： correlated MIMO system linear precoding MMSE receiver channel estimation power allocation

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Transceiver Design for MIMO Systems with Improper Modulations

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WIRELESS PERSONAL COMMUNICATIONS 2013年第2期68卷 265-280页

作者： Raja, M. Muthuchidambaranathan, P. Nguyen, Ha H. Natl Inst Technol Dept Elect & Commun Engn Tiruchirappalli Tamil Nadu India Univ Saskatchewan Dept Elect & Comp Engn Saskatoon SK S7N 5A9 Canada

This paper considers joint transceiver designs for single-user multiple-input, multiple-output systems employing improper constellations such as binary phase shift-keying and M-ary amplitude shift-keying (M-ASK). Proposed are novel joint linear transceivers that minimize the total mean squared error of the symbol estimation at the output of the decoder. The joint linear transceiver designs are carried out for both cases of perfect channel state information (CSI) and imperfect CSI at the transmitter and receiver. For the case of imperfect CSI, the channel model takes into account both transmit and receive correlations as well as the channel estimation error. The superiority of the proposed transceivers over the previously-proposed designs is verified by simulation results.

关键词： Channel state information (CSI) Mean-square error (MSE) Multiple-input multiple-output (MIMO) linear precoding Spatial multiplexing Improper modulations

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Onboard Beam Generation for Multibeam Satellite Systems

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2017年第6期16卷 3714-3726页

作者： Joroughi, Vahid Angel Vazquez, Miguel Perez-Neira, Ana I. Devillers, Bertrand Univ Vigo Vigo 36310 Spain Ctr Tecnol Telecomunicac Catalunya Barcelona 08860 Spain Univ Politecn Cataluna ES-08034 Barcelona Spain European Patent Off Munich Germany

This paper aims at designing an onboard beam generation process for a hybrid onboard on-ground multibeam satellite architecture. The proposed method offers a good tradeoff between total throughput and feeder link bandwidth requirements compared with pure on-ground systems. Full frequency reuse among beams is considered, and the beamforming at the satellite is designed for supporting interference mitigation techniques. In addition, in order to reduce the payload cost and complexity, this onboard beamforming is assumed to be constant and the same for forward and return link transmissions so that the same array-fed reflector can be used for forward and return links, leading to a substantial reduction of the payload mass. To meet all these requirements, a novel robust minimum mean square error optimization is conceived. The benefits of the considered scheme are evaluated with respect to the current approaches both analytically and numerically. Indeed, we show that with the DVB-RCS and DVB-S2 standards, our proposal allows increasing the total throughput within a range between 6% and 15% with respect to other onboard processing techniques in the return and forward link, respectively.

关键词： Multibeam satellite systems on-board beam processing linear precoding DVB-S2 DVB-RCS

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Secrecy Rates in Broadcast Channels with Confidential Messages and External Eavesdroppers

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2014年第5期13卷 2931-2943页

作者： Geraci, Giovanni Singh, Sarabjot Andrews, Jeffrey G. Yuan, Jinhong Collings, Iain B. Univ New S Wales Sch Elect Engn & Telecommun Sydney NSW 2052 Australia Univ Texas Austin WNCG Austin TX 78712 USA CSIRO ICT Ctr Wireless & Networking Technol Lab Sydney NSW Australia

In this paper, we consider the broadcast channel with confidential messages and external eavesdroppers (BCCE), where a multi-antenna base station simultaneously communicates to multiple potentially malicious users, in the presence of randomly located external eavesdroppers. Using the proposed model, we study the secrecy rates achievable with regularized channel inversion (RCI) precoding by performing a large-system analysis that combines results from stochastic geometry and random matrix theory, where the number of users K and the number of transmit antennas N both grow to infinity in a fixed ratio. We obtain explicit expressions for the probability of secrecy outage and an upper bound on the rate loss due to the presence of external eavesdroppers. We show that both these quantities scale as lambda e/root N as the density of external eavesdroppers lambda e grows, irrespective of their collusion strategy. Furthermore, we derive a practical rule for the choice of the regularization parameter, which is agnostic of channel state information and location of eavesdroppers, and yet provides close to optimal performance.

关键词： Physical layer security broadcast channel linear precoding stochastic geometry random matrix theory

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Generalized Channel Inversion Methods for Multiuser MIMO Systems

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IEEE TRANSACTIONS ON COMMUNICATIONS 2009年第11期57卷 3489-3499页

作者： Sung, Hakjea Lee, Sang-Rim Lee, Inkyu Korea Univ Sch Elect Eng Seoul South Korea

Block diagonalization (BD) is a well-known pre-coding method in multiuser multi-input multi-output ( MIMO) broadcast channels. This scheme can be considered as a extension of the zero-forcing (ZF) channel inversion to the case where each receiver is equipped with multiple antennas. One of the limitation of the BD is that the sum rate does not grow linearly with the number of users and transmit antennas at low and medium signal-to-noise ratio regime, since the complete suppression of multi-user interference is achieved at the expense of noise enhancement. Also it performs poorly under imperfect channel state information. In this paper, we propose a generalized minimum mean-squared error (MMSE) channel inversion algorithm for users with multiple antennas to overcome the drawbacks of the BD for multiuser MIMO systems. We first introduce a generalized ZF channel inversion algorithm as a new approach of the conventional BD. Applying this idea to the MMSE channel inversion for identifying orthonormal basis vectors of the precoder, and employing the MMSE criterion for finding its combining matrix, the proposed scheme increases the signal-to-interference-plus-noise ratio at each user's receiver. Simulation results confirm that the proposed scheme exhibits a linear growth of the sum rate, as opposed to the BD scheme. For block fading channels with four transmit antennas, the proposed scheme provides a 3dB gain over the conventional BD scheme at 1 % frame error rate. Also, we present a modified precoding method for systems with channel estimation errors and show that the proposed algorithm is robust to channel estimation errors.

关键词： Multi-input multi-output (MIMO) multiuser broadcast channels (BC) linear precoding minimum mean-squared error (MMSE)

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Channel estimation techniques for linear precoded systems: Supervised, unsupervised, and hybrid approaches

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SIGNAL PROCESSING 2011年第7期91卷 1578-1588页

作者： Castro, Paula M. Garcia-Naya, Jose A. Dapena, Adriana Iglesia, Daniel Univ A Coruna Dept Elect & Syst La Coruna 15071 Spain

linear precoding is an attractive technique to combat interference in multiple-input multiple-output systems because it reduces cost and power consumption at the receiver. Frequency division duplex systems with linear precoding acquire the channel state information at the receiver side by using supervised algorithms. Such methods make use of pilot symbols periodically provided by the transmitter. Next, this channel state information is sent to the transmitter side through a low-cost feedback channel. Thus, the available channel information allows the transmitter to adapt signals to the channel conditions. Given that pilot symbols do not convey user data, they penalize throughput, spectral efficiency, and transmission energy consumption of the system. In this work, we propose to mitigate the aforementioned limitations by combining both supervised and unsupervised algorithms to acquire the channel state information needed by the transmitter. The key idea consists in introducing a simple criterion to determine whether the channel has suffered a significant variation which requires the transmission of pilot symbols. Otherwise, when small fluctuations happen, an unsupervised method is used to track these channel variations instead. This criterion will be evaluated by considering two types of strategies for the design of the linear precoders: Zero-Forcing and Wiener criteria. (C) 2011 Elsevier B.V. All rights reserved.

关键词： linear precoding MIMO Blind Source Separation Learning Rules

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linear Precoder Design for Simultaneous Information and Energy Transfer Over Two-User MIMO Interference Channels

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2015年第10期14卷 5836-5847页

作者： Ozcelikkale, Ayca Duman, Tolga M. Chalmers Univ Technol Dept Signals & Syst S-41296 Gothenburg Sweden Bilkent Univ Dept Elect Engn TR-06800 Ankara Turkey

Communication strategies that utilize wireless media for simultaneous information and power transfer offer a promising perspective for efficient usage of energy resources. With this motivation, we focus on the design of optimal linear precoders for interference channels utilizing such strategies. We formulate the problem of minimizing the total minimum mean-square error while keeping the energy harvested at the energy receivers above given levels. Our framework leads to a non-convex problem-formulation. For point-to-point multiple-input multiple-output channels, we provide a characterization of the optimal solutions under a constraint on the number of transmit antennas. For the general interference scenario, we propose two numerical approaches, one for the single antenna information receivers case, and the other for the general case. We also investigate a hybrid signalling scheme, where the transmitter sends a superposition of two signals: a deterministic signal optimized for energy transfer and an information carrying signal optimized for information and energy transfer. It is illustrated that if hybrid signalling is not incorporated into the transmission scheme, interference can be detrimental to the system performance when the number of antennas at the receivers is low.

关键词： Wireless power transfer energy harvesting simultaneous wireless information and power transfer (SWIPT) interference linear precoding MMSE

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