Antenna selection with superposition for 4 x 2 DSTTD systems

Jingon Joung,Sayed, A.H.,Lee, Y.H. IEEE 2009 IEEE COMMUNICATIONS LETTERS Vol.13 No.7

<P>From 1820 4 times 4 binary matrices, 253 binary preprocessing matrices are designed for double space-time transmit diversity (DSTTD) systems with two 2 times 2 space-time block code (STBC) encoders. Among them, six matrices yielding the highest average minimum-post-processing SNR are proposed from numerical experimentation under uncorrelated channel conditions. The proposed preprocessing performs a superposition of the first and second (second and first) STBC symbols and a selection of two transmit antennas. Simulation results show that the proposed method provides 1.7 dB (1.8 dB) SNR improvement in uncorrelated (correlated) channel environment at 10<SUP>-3</SUP> bit error rate over the conventional antenna shuffling method.</P>

Linear Precoder Design for an AF Two-Way MIMO Relay Node with No Source Node Precoding

Joung, Jingon,Choi, Jihoon IEEE 2017 IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY Vol.66 No.11

<P>In this paper, an amplify-and-forward two-way relay (TWR) precoding is designed with no source node (SN) processing in order tomaximize sum rate and concurrently reduce the network latency and signaling overhead. For the arbitrary pre-/postprocessing at the SNs that have N antennas, it is rigorously shown that an N-by-N optimal TWR precoder matrix is symmetric when the noise power of the TWR node is relatively small compared with that of the SNs and/or each of the channel matrices is spatially orthogonal. Using the symmetric structure of the TWR precoding matrix, a constrained nonlinear-multivariable optimization problem is formulated that can be solved with polynomial time complexity. Furthermore, a closed-form optimal TWRprecoding matrix is designed for aTWR system with N = 2. When compared with an optimal joint SN andRNprecoding method, it is verified that the proposed precoding method provides a good tradeoff between the system complexity and sum rate performance.</P>

Transmit Antenna Shuffling for Orthogonal Space–Time Block Code Systems Using Uneven Power Amplifiers

Joung, Jingon,Choi, Jihoon IEEE 2018 IEEE Transactions on Vehicular Technology VT Vol.67 No.7

<P>A transmit antenna shuffling method combined with an orthogonal space-time block code (OSTBC) is proposed for a system using <TEX>$M$</TEX> transmit antennas with asymmetric power amplifiers (PAs) having uneven gains. Considering the uneven gains of PAs, we design an optimal antenna shuffling method with <TEX>$\lceil {log}_2(M!) \rceil$</TEX> -bit feedback to maximize the detection signal-to-noise ratio (SNR). To reduce the feedback, a suboptimal method with <TEX>$\lceil {log}_2M\rceil$</TEX> -bit feedback is proposed. A theoretical analysis and numerical results verify that antenna shuffling can significantly improve the detection SNR of the OSTBC system with uneven PA gains and that the SNR loss of the suboptimal method is marginal.</P>

A Computationally Efficient Criterion for Antenna Shuffling in DSTTD Systems

Jingon Joung,Eui-Rim Jeong,Lee, Y.H. IEEE 2007 IEEE communications letters Vol.11 No.9

<P>The application of double space-time transmit diversity (DSTTD) scheme to multicarrier systems, such as orthogonal frequency division multiplexing (OFDM) systems, requires calculating the determinations of the antenna permutation matrices for all subcarriers, resulting in a heavy computation load. In this paper, we show that the signal-to-noise ratio (SNR)-based antenna shuffling criterion for DSTTD systems can be reduced to a simple criterion that evaluates determinants of 2 times 2 submatrices of the 4 times 4 equivalent channel matrix. The new criterion can lighten the computational load by about 95%. Furthermore, it is shown that the minimum mean square error (MMSE)-based criterion for antenna permutation can also be reduced to the same criterion.</P>

Multiuser Two-Way Amplify-and-Forward Relay Processing and Power Control Methods for Beamforming Systems

Jingon Joung,Sayed, A.H. IEEE 2010 IEEE transactions on signal processing Vol.58 No.3

<P>In this paper, multiple-input multiple-output (MIMO) relay transceiver processing is proposed for multiuser two-way relay communications. The relay processing is optimized based on both zero-forcing (ZF) and minimum mean-square-error (MMSE) criteria under relay power constraints. Various transmit and receive beamforming methods are compared including eigen beamforming, antenna selection, random beamforming, and modified equal gain beamforming. Local and global power control methods are designed to achieve fairness among all users and to maximize the system signal-to-noise ratio (SNR). Numerical results show that the proposed multiuser two-way relay processing can efficiently eliminate both co-channel interference (CCI) and self-interference (SI).</P>

Regularized Channel Diagonalization for Multiuser MIMO Downlink Using a Modified MMSE Criterion

Joung, Jingon,Lee, Yong H. IEEE 2007 IEEE transactions on signal processing Vol.55 No.4

<P>We propose a regularized channel diagonalization method for a joint transmit-receive linear optimization in the downlink of a multiuser multiple-input multiple-output (MIMO) communication system. This method is based on the use of a modified minimum mean-square error (MMSE) criterion, which employs a weighted information symbol vector for the target and signal scaling. The weights for the target are the equivalent channel gain resulting from a zero-forcing (ZF)-based MIMO channel diagonalization. A joint iterative algorithm for minimizing the mean-square error (MSE) under a total transmit power constraint is derived, and its convergence is proved. The signal-to-interference-plus-noise ratio (SINR) is analyzed and the sum rates evaluated in a computer simulation. The results demonstrate that the proposed method outperforms the existing ZF- and MMSE-based methods</P>

User Selection Methods for Multiuser Two-Way Relay Communications Using Space Division Multiple Access

Joung, Jingon,Sayed, Ali H. IEEE 2010 IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS Vol.9 No.7

<P>In this paper, we design a multiuser two-way relay system using space division multiple access (SDMA) communications and devise an optimal scheduling method that maximizes the sum rate while ensuring fairness among users. To reduce the computational load at the relays, we propose rate- and angle-based suboptimal scheduling methods. The numerical results illustrate tradeoff between complexity and the performance. Specifically, when the relay has two antennas, we verify that the rate-based method can provide significant computational savings at the cost of a rate reduction of less than 4% when compared with the optimal scheduling method.</P>

CSI Partitioning Method with PCA-Based Compression for Low-Complexity Feedback of Large-Dimensional Channels

Joung, Jingon,Kurniawan, Ernest IEEE 2017 IEEE Communications Letters Vol.21 No.3

<P>This letter considers a codebook-based channel state information (CSI) feedback technique for large-dimensional channels, e.g., massive multiple-input multiple-output (MIMO) channels. We propose a CSI partitioning method, focus on the search complexity required in order to obtain the best beamforming vector, and investigate the tradeoff between the complexity and the performance. Then, we present an analytical framework that provides design guidelines for balancing the complexity, performance, and feedback overhead of practical large-scale MIMO systems.</P>

Blind Symbol and Carrier Synchronization with Carrier Frequency Offset Estimation for Space-Time Line Coded Systems

Jingon Joung,Eui-Rim Jeong,Hyukjun Oh 한국통신학회 2023 ICT Express Vol.9 No.2

In this study, utilizing the structure of the space–time line code (STLC) signals, a blind symbol and carrier synchronization method considering the carrier frequency offset (CFO) is developed. The proposed method can achieve almost perfect synchronization performance with more than three transmit antennas, irrespective of the CFO values. Based on the results, the proposed blind symbol and carrier synchronization method is expected to accelerate the practical deployment and operation of the low-complexity STLC systems that achieve full spatial diversity gain with partial or no channel state information at the receiver.

Distributed Precoder Design With Direct-Link Channel Information for Distributed Antenna Systems

Joung, Jingon,Nguyen, Hieu Duy,Sun, Sumei IEEE 2018 IEEE Transactions on Vehicular Technology VT Vol.67 No.4

<P>In this study, we investigate distributed antenna systems (DASs) with partial channel state information (CSI). In the DAS considered here, one control unit coordinates multiple baseband units (BBUs), and each BBU with multiple distributed antennas (DAs) knows only the direct channels from its DAs to its associated users and supports them simultaneously. For fairness among users, a distributed precoder structure is designed to maximize the upper bound of the minimum user rate, under the assumption that the direct channel dominates the intra-BBU interfering links. We then propose a distributed general precoder that allows multiple BBUs to serve multiple users simultaneously. Numerical results verify that, in terms of the minimum and average achievable rates, the proposed scheme significantly outperforms an existing scheme in which each BBU supports a single user. The results also demonstrate that the proposed scheme is comparable to a full-CSI based scheme.</P>