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Tensor-Based Channel Estimation Approach for One-Way Multi-Hop Relaying Communications
( Shuangzhi Li ),( Xiaomin Mu ),( Xin Guo ),( Jing Yang ),( Jiankang Zhang ) 한국인터넷정보학회 2015 KSII Transactions on Internet and Information Syst Vol.9 No.12
Multi-hop relaying communications have great potentials in improving transmission performance by deploying relay nodes. The benefit is critically dependent on the accuracy of the channel state information (CSI) of all the transmitting links. However, the CSI has to be estimated. In this paper, we investigate the channel estimation problem in one-way multi-hop MIMO amplify-and-forward (AF) relay system, where both the two-hop and three-hop communication link exist. Traditional point-to-point MIMO channel estimation methods will result in error propagation in estimating relay links, and separately tackling the channel estimation issue of each link will lose the gain as part of channel matrices involved in multiple communication links. In order to exploit all the available gains, we develop a novel channel estimation model by structuring different communication links using the PARAFAC and PARATUCK2 tensor analysis. Furthermore, a two-stage fitting algorithm is derived to estimate all the channel matrices involved in the communication process. In particular, essential uniqueness is further discussed. Simulation results demonstrate the advantage and effectiveness of the proposed channel estimator.
Energy Efficiency of Very Large Multiuser MIMO Systems with Transmit Antenna Selection
Jie Li,Shuangzhi Li,Xiaomin Mu,Jiankang Zhang 보안공학연구지원센터 2015 International Journal of Multimedia and Ubiquitous Vol.10 No.6
In this paper, transmit antenna selection is performed to improve the energy efficiency of multiuser large scale MIMO systems, which is necessary for the energy efficiency maximization of large scale MIMO, because the RF chains which are connected with antennas are very expensive and consume a lot of power. However, the consumed power of the large scale MIMO systems should include not only transmit power but also the fundamental power for operating the circuit at the transmitter, because the effect of circuit power consumption is more serious when the transmitter is equipped with massive number of antennas. We evaluate the performance of the energy efficiency in the multiuser case where zero-forcing precoding is used to reduce the inter-user interference. The theoretical analysis indicates that there exists an optimal number of selected antennas to maximize the energy efficiency, and we derive optimal antenna number for different number of users. All the analytical results are verified through both mathematical analysis and numerical simulations.
Energy Efficiency Optimization for Uplink Multiuser MIMO Systems
Lina Ma,Shuangzhi Li,Xiaomin Mu 보안공학연구지원센터 2016 International Journal of Multimedia and Ubiquitous Vol.11 No.8
To satisfy green communication needs, energy efficiency is regraded as one of the most important indicators to evaluate the effectiveness of a communication system. In this paper, we establish the energy efficiency optimization framework for uplink multiuser mutliple-input multiple-output system. Taking the circuit power, the antenna link power and signal processing power into consideration, an analytical expression of the achieveable energy efficiency is firstly established, which can better model the practical communication process. Furthermore, we simplify the objective function under some mild conditions. After demonstrating the existence of a unique golbally optimal energy efficiency, an adaptive water-filling power allocation algorithm is proposed to further improve the energey efficiency of the system. Finally some simulation results are given to verify the performance of our scheme. Our work can provide a fundamental principles for uplink mutiluser multiple-input multiple-output systems design.