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adaptive precoding and power allocation in distributed antenna systems with limited feedback

WIRELESS COMMUNICATIONS & MOBILE COMPUTING 2015年第5期15卷 834-847页

作者： Chen, Xiaoming Lei, Lei Nanjing Univ Aeronaut & Astronaut Coll Elect & Informat Engn Nanjing Jiangsu Peoples R China Southeast Univ Natl Mobile Commun Res Lab Nanjing Jiangsu Peoples R China

This paper introduces the limited feedback precoding into the distributed antenna system and proposes to adapt the predetermined orthogonal space time block codes to the available channel state information at the transmitter. The optimal representation of precoding information, namely the precoder, with least bits therefore becomes the key problem. Inspired by the characteristics of the distributed antenna system, we focus our work on the precoder construction, adaptable in response to the large and small scale fading, such that the symbol error probability is significantly reduced over that of a fixed, non-adaptive, independent and identically distributed precoder codebook design. Furthermore, a suboptimal power-loading strategy is presented by minimizing the derived tight upper bound on the average pairwise error probability of the precoded orthogonal space time block codes, which approaches the optimal performance asymptotically without additional channel knowledge other than the available feedback information. We prove that the proposed precoded orthogonal space time transmission scheme can achieve full diversity order. In particular, the robustness of our proposed transmission scheme to channel estimation error and feedback delay is respectively investigated in some detail, and numerical results show that it obviously improves the link reliability and obtains substantial gains even with few bits of feedback in comparison with conventional antenna selection scheme. Copyright (c) 2013 John Wiley & Sons, Ltd.

关键词： distributed antenna system (DAS) orthogonal space time block code (OSTBC) adaptive precoding limited feedback power allocation imperfect CSI

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adaptive precoding for wireless MIMO broadcast channels with limited feedback

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IEICE TRANSACTIONS ON COMMUNICATIONS 2005年第11期E88B卷 4237-4245页

作者： Kim, J Kim, J Park, CS Lee, KB Seoul Natl Univ EECS EE Seoul South Korea SAMSUNG AIT Commun & Network Lab Suwon South Korea

Recently, a number of techniques have been introduced to exploit multiuser diversity of a wireless multiple-input multiple-output (MIMO) broadcast channel (BC) that consists of a base station with t transmit antennas and K users with multiple antennas. However, prior works have ignored the rate overhead associated with feedback of MIMO BC channel state information at transmitter (CSIT), which is roughly K times larger than single-user MIMO CSIT (i.e., itis O(tr) where r =Sigma k=1/k r(k) and r(k) is the number of antennas at the kth user). Considering the amount of feedback signaling, quantization is a necessity for effective feedback transmission as a form of partial CSIT. In this paper, we propose the greedy multi-channel selection diversity (greedy MCSD) scheme based on block MMSE QR decomposition with dirty paper coding (block MMSE-DP), where partial CSIT is almost sufficient. The sum-rate performance of our novel scheme approaches extremely close to the sum capacity of MIMO BC as the number of users increases, whereas the feedback overhead is reduced by a factor of 2t(3)/L(t(2)-t), in which Lis the number of active channel vectors. Simulation results validate the expectation from the analysis. In addition, the proposed scheme is shown to be appropriate for reconfigurable implementation.

关键词： MIMO broadcast channel (BC) adaptive precoding SDR implementation

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An adaptive precoding scheme in MIMO systems

An adaptive precoding scheme in MIMO systems

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International Conference on Information Technology and Industrial Engineering

作者： Zheng, Feng Shi, Yang Chen, Yijian Beijing Univ Posts & Telecommun Beijing 100088 Peoples R China ZTE Corp Wireless Res Dept Shenzhen Peoples R China

ISBN: (纸本)9781845648442;9781845648435

This paper proposes an adaptive precoding technology for Multiple user Multiple-Input Multiple-Output (MU-MIMO) systems based on these typical precoding models's characteristics. The main idea of the adaptive scheme is switching precoding mode among these typical precoding schemes. Through observing, I find that the BER performance by using linear precoding is better than that by taking nonlinear precoding when SNR is low. The BER performance by using linear precoding is worse than that by taking nonlinear precoding when SNR is high. Then, an adaptive precoding scheme combines linear and nonlinear precoding technologies when the critical point of SNR is found. In addition, based on different configuration of User Equipment, it uses more specific precoding mode so that it makes further improvement on performance and reduces cost. In this way, this adaptive precoding scheme is considered performance in MIMO systems and complexity degree synthetically. Therefore, adaptive precoding scheme is more efficient and dynamic than traditional precoding scheme.

关键词： MIMO systems linear precoding nonlinear precoding adaptive precoding

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On precoding Diversity in Cognitive Networks 23

On Precoding Diversity in Cognitive Networks

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23rd International Conference on Telecommunications (ICT)

作者： Yaqot, Abdullah Hoeher, Peter Adam Univ Kiel Informat & Coding Theory Lab Kiel Germany

ISBN: (纸本)9781509019908

In this paper, we propose an adaptive linear precoder design for an underlay cognitive radio (CR) multiuser MIMO broadcasting system. The proposed adaptive precoder employs regularized channel inversion based on the minimum mean square error (MMSE) criterion. Unlike the conventional MMSE precoder, the proposed precoder exploits degrees of freedom not being used so far, which considerably improves the signal-to-interference-plus-noise (SINR) ratio at the receiver of each CR user while fulfilling the underlay CR constraints. Simulation results illustrate good SNR and spectral efficiency gains over the state-of-the-art.

关键词： adaptive precoding MMSE Cognitive radio MIMO broadcasting precoding diversity

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Efficient Resource Allocation in Cognitive Networks

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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2017年第7期66卷 6349-6361页

作者： Yaqot, Abdullah Hoeher, Peter Adam Univ Kiel Chair Informat & Coding Theory D-24143 Kiel Germany

Cognitive radio (CR) in conjunction with multiple-input multiple-output (MIMO) orthogonal frequency-division multiple access is a candidate technology for future mobile radio networks. The short communication range of underlay CR systems is commonly a major limiting factor. In this paper, we propose a computationally and spectrally efficient resource allocation scheme for multiuser MIMO orthogonal-frequency-divisionmultiplexing-based underlay CR networks to provide good spectral efficiency gain and, therefore, increased communication range. Since the formulated optimization problem defines a mixed-integer programming (combinatorial task) that is hard to solve, we propose a two-phase scheme to produce efficient solutions for both the downlink and the uplink. Particularly, the first procedure elaborates on an adaptive precoding that is characterized by spectral efficiency due to the degrees of freedom it can provide. The second procedure develops a fast subcarrier mapping algorithm, which can be worked out through optimal power distribution among the CR users. The proposed scheme is optimal for the downlink but, however, near-optimal for the uplink. Simulation results demonstrate the bandwidth and computational efficiencies of the proposed scheme compared with the state of the art.

关键词： adaptive precoding cognitive radio (CR) convex optimization multiple-input multiple-output orthogonal frequency-division multiplexing(MIMO-OFDM) subcarrier mapping

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adaptive Generalized Space Shift Keying and Downlink Multi-user Transmission in MIMO Fading Channels

Adaptive Generalized Space Shift Keying and Downlink Multi-u...

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IEEE International Conference on Communication Systems (IEEE ICCS)

作者： Liang, Dong Ren, Pinyi Sun, Li Du, Qinghe Wang, Yichen Xi An Jiao Tong Univ Sch Elect & Informat Engn Xian 710049 Peoples R China Southeast Univ Natl Mobile Commun Res Lab Nanjing 210096 Jiangsu Peoples R China

ISBN: (纸本)9781479958320

To achieve spatial diversity and improve the average bit error probability (ABEP) of Generalized Space Shift Keying (GSSK) in Multiple-Input and Multiple-Output (MIMO) channels with low feedback overhead and computational complexity, we propose a three-step adaptive precoding strategy for single-user GSSK (SU-GSSK) transmission by exploiting the channel state information at the transmitter (CSIT). First, a norm based reference receive antenna selection is conducted to maximize the selection gain. Second, active transmit antennas are coherently superposed to boost the signal to noise ratio (SNR) on the reference receive antenna. Third, phase-rotation processing is introduced to maximize the Euclid distance of the spatial constellation diagram. By applying the above steps, better ABEP performance can be obtained compared to the baseline schemes, with remarkably reduced feedback and complexity. Moreover, combining with the proposed adaptive precoding strategy, we design a resource-saving method for multi-user (MU) data conveying by preprocessing and stacking all users' spatial constellations on increased number of active antennas and then implement a downlink MU-GSSK transmission scheme to provide several times the sum rate compared to SU-GSSK with acceptable ABEP performance. Complexity analysis and simulations show the effectiveness and scalability of our proposed schemes.

关键词： Generalized space shift keying adaptive precoding low-complexity spatial diversity multi-user transmission

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