BER performance of SVD-based transmit beamforming with various modulation techniques

In this paper, we present a beamforming technique using singular value decomposition (SVD) for closed loop multiple-input multiple-output (MIMO) wireless systems with various modulation techniques such as binary phase shift keying (BPSK) and 16- quadrature amplitude modulation (16-QAM). The channel matrix is decomposed into a number of independent orthogonal modes of excitation, which we will refer to as eigenmodes of the channel. The transmit precoding is performed by multiplying the input symbols with unitary matrix to produce the transmit beamforming, and the precoded symbols are transmitted over Rayleigh fading channel. At the receiver, combining process is performed for receiving symbols by using maximum ratio combiner (MRC), and the receiver shaping is performed to retrieve the original input symbols by multiplying the received signal with conjugate transpose of the unitary matrix. Furthermore, we derive expressions for average bit error rate (BER) for BPSK and average symbol error rate (SER) for M-QAM. Simulation results demonstrate that the proposed SVD-based beamforming schemes yield the better performance when compare to the other beamforming method.