Signal-to-leakage-and-noise Ratio Research Articles

A New Multi-User Beamforming Algorithm

In R9 version of LTE system, the double multi-user beamforming is proposed. To suppress inter-user interference of multi-user multiple input multiple output (MU-MIMO) system, a new algorithm is presented in this paper: on condition that current user eliminates the interference to other users, it designs its own transmit beamforming vector; if all users take such measures, the interference that each user suffers from others will be reduced to a minimum, which improves the performance of the system. Simulation shows that, as the number of user increases, the algorithm used in this paper can reduce the bit error rate (BER) of the system more obviously than the traditional signal-to-leakage-and-noise ratio (SLNR) algorithm.

Generalised singular value decomposition-based algorithm for multi-user multiple-input multiple-output linear precoding and antenna selection

Multi-user multiple-input multiple-output (MU-MIMO) linear precoding utilising generalised singular value decomposition (GSVD) is proposed. The authors precoding scheme maximises the signal-to-leakage and noise ratio (SLNR), so that it does not require any iteration to obtain precoding/decoding matrices, a feature that distinguishes it from previous signal to interference and noise ratio (SINR) maximising precoding schemes. The SLNR maximising precoding weight may be obtained by the generalised eigenvalue decomposition (GEVD). However, the covariance matrix whose GEVD is computed becomes near singular as the signal-to-noise ratio goes high. To overcome this numerical problem, the proposed precoding scheme avoids any matrix inversion and matrix ‘squaring’ operations, removing redundant computational loads, and consequently saves computational resources and improves numerical accuracy. To further improve the system performance, an efficient antenna selection scheme using the GSVD is also proposed. The scheme does not require an exhaustive search to choose an active antenna set.

A New SLNR-Based Linear Precoding for Downlink Multi-User Multi-Stream MIMO Systems

Signal-to-leakage-and-noise ratio (SLNR) is a promising criterion for linear precoder design in multi-user (MU) multiple-input multiple-output (MIMO) systems. It decouples the precoder design problem and makes closed-form solution available. In this letter, we present a new linear precoding scheme by slightly relaxing the SLNR maximization for MU-MIMO systems with multiple data streams per user. The precoding matrices are obtained by a general form of simultaneous diagonalization of two Hermitian matrices. The new scheme reduces the gap between the per-stream effective channel gains, an inherent limitation in the original SLNR precoding scheme. Simulation results demonstrate that the proposed precoding achieves considerable gains in error performance over the original one for multi-stream transmission while maintaining almost the same achievable sum-rate.