Yier Yan

Generalized Precoding-Aided Quadrature Spatial Modulation

In this paper, we propose a novel scheme, which is called generalized precoding-aided quadrature spatial modulation (GPQSM), that extends the conventional quadrature spatial modulation to the receiver side. In GPQSM, spatial modulation works in both the in-phase and quadrature parts of the received signals, thus conveying additional information bits compared with conventional generalized precoding-aided spatial modulation (GPSM). The proposed scheme is general and can degenerate into the conventional multiple-input multiple-output (MIMO) scheme. A closed-form upper bound on the average bit error probability of GPQSM is derived. Simulation results verify the theoretical analysis and show that GPQSM outperforms the conventional GPSM scheme and the MIMO scheme under the same spectral efficiency.

Differential Spatial Modulation With Gray Coded Antenna Activation Order

In this letter, we propose a gray code order of antenna index permutations for differential spatial modulation (DSM). To facilitate the implementation, the well-known Trotter-Johnson ranking and unranking algorithms are adopted, which result in similar computational complexity to the existing DSM that uses the lexicographic order. The signal-to-noise ratio gain achieved by the proposed gray code order over the lexicographic order is also analyzed and verified via simulations. Based on the gray coding framework, we further propose a diversity-enhancing scheme named intersected gray (I-gray) code order, where the permutations of active antenna indices are selected directly from the odd (or even) positions of the full permutations in the gray code order. From analysis and simulations, it is shown that the I-gray code order can harvest an additional transmit diversity order with respect to the gray code order.

Low Complexity Detection for Quadrature Spatial Modulation Systems

Quadrature spatial modulation (QSM), where the real and imaginary parts of the transmitted symbol are transmitted separately, was recently proposed to increase the spectral efficiency of spatial modulation. An optimum maximum likelihood (ML) detection was introduced in QSM systems, which leads to high complexity as the exhausting search of all possible transmit antennas. In this paper, a low complexity detection, called signal vector based minimum mean square error (SVMMSE), is proposed for QSM systems. In the proposed SVMMSE detection, we estimate the transmit antenna indices and the transmitted symbol by considering the active transmit antennas in two different scenarios. Simulation results show that the performance of our SVMMSE detection is very close to the ML detection and complexity analysis shows that the computational complexity of the proposed SVMMSE detection is significantly reduced compared with that of the ML detection.

Ternary codes from modified Jacket matrices

In this paper, we construct two families C_m* and C̃_m* of ternary (2^m, 3^m, 2^m-1) and (2^m 3^m+1, 2^m-1) codes, for m = 1, 2, 3, ⋯, derived from the corresponding families of modified ternary Jacket matrices. These codes are close to the Plotkin bound and have a very easy decoding procedure.

Tensor decomposition of Toeplitz Jacket matrices for big data processing

In this paper, we consider the tensor decomposition (TD) of Toeplitz Jacket (TJ) matrices for big data processing by using the conventional higher order singular value decomposition (HOSVD) algorithm and Tensor train (TT) decomposition. In order to use HOSVD algorithm and TT decomposition, we reshape the given matrix and make it as a tensor. Due to the property of Toeplitz matrices, we use a truncated TJ matrix in stead of given matrix to reduce the complexity of TD. The results verified that the TD of the truncated TJ matrices gains a lower complexity due to smaller size of factor matrices and core tensors.

Construction of multiple-rate quasi-cyclic LDPC codes via the hyperplane decomposing

This paper presents an approach to the construction of multiple-rate quasi-cyclic low-density parity-check (LDPC) codes. Parity-check matrices of the proposed codes consist of q X q square submatrices. The block rows and block columns of the parity-check matrix correspond to the hyperplanes (μ-flats) and points in Euclidean geometries, respectively. By decomposing the μ -flats, we obtain LDPC codes of different code rates and a constant code length. The code performance is investigated in term of the bit error rate and compared with those of LDPC codes given in IEEE standards. Simulation results show that our codes perform very well and have low error floors over the additive white Gaussian noise channel.

A novel high rate transmission scheme for space time coding with low decoding complexity

In this paper, we propose a new method to transmit one more information bit by using orthogonal Space-Time Block Codes (STBC) for 4 antennas. Using two different STBCs matrices transmit one additional bit to achieve high rate-9/8. To maintain full rank and full diversity for the coding gain matrix, a new STBC code with full rate and full diversity is proposed in this letter. In order to implement a fast Maximum-likelihood (ML) decoding, a property of Frobenius norms of received signals is considered to reduce its complexity by checking the non-null values of the Frobenius at the transmitter side. Simulation results show that this method achieves better bit error rate (BER) performance and throughputs in the high SNR region without losing diversity gain.

Joint channel estimation in asynchronous amplify-and-forward relay networks based on OFDM signaling

In this paper, we propose a method on the training based on channel estimation issues for relay networks that employ amplify-and-forward (AF) transmission scheme. In [1] and [2], we have to point out that jointly estimating the channel from source to relay and relay to destination suffers from many drawbacks in fast fading case because the estimation of previous pilots is not suitable for current channel. In this paper we consider a new joint estimation of overall channel impulse response (CIR) using one OFDM signal without pilots. Using the maximum likelihood (ML) function, we derive a channel estimator by taking the frequency domain of transmitted signal as Gaussian and averaging the ML function over the resulting Gaussian distribution. Simulation results show that our proposed channel estimator performs a fraction of 1dB compared with [1] in high SNR region.

Novel control signal detection for high-rate transmission in LTE-OFDM systems

The control signal (CS) is an integral essential part for the transmission of uplink and downlink channels in long-term evolution (LTE) systems. Hence, an inaccurate detection method for the CS leads to a severe performance degradation. In this paper, we propose a novel CS detection method for LTE-orthogonal frequency division multiplexing (OFDM) systems. The proposed method dispenses with the channel estimation compared with the conventional maximum-likelihood (ML) detection, which avoid intersecting the pilots in the transmitted signals. Duo to this fact, our proposed detection method can increase the system transmission rate without any additional expense. Monte-Carlo simulations are performed. The simulation results show that the proposed detection outperforms the ML detection when transmitting a large length of control signals.

A class of alamouti-like orthogonal space-time block codes for high-rate transmission

We propose a class of Alamouti-like Orthogonal Space-Time Block Codes (STBC) for two additional information bits without source such as power, bandwidth and time slot. To maintain the full rank property of the coding gain matrix, we propose a set of STBCs for 4 transmit antennas transmission to transmit one additional information bit achieving rate-9/8. Another orthogonal STBC code with rate-1 is proposed in this paper within the set. It shows by computer simulation results that by employing the set of STBCs, it achieves better bit error rate (BER) performance and throughput than that of [1] with a valid BER improvement at high SNR region above 20dB.