Abstract: This paper is concerned with a two hop half-duplex wireless communication network with multiple antennas and multiple relays. Based on amplifyandforward (AF) protocol, two new distributed beamforming schemes named IRZF-MF and RZF were proposed for this system. The RZF scheme uses RZF technique for both receive and transmit beamforming while the IRZF-MF scheme uses IRZF and MF technique for receive and transmit beamforming respectively. The simulation results show that the proposed two relay schemes achieve the same performance of existing MF-RZF scheme in the Rayleigh channel, meanwhile, the proposed RZF scheme achieves the best performance which requires a higher computational complexity and the proposed IRZFMF scheme achieves the second best performance while requires less computational complexity than RZF scheme in the Rician channel compared with other existing distributed relaying schemes. Key words：

Key words: multiple-input multiple-output (MIMO), AF relay, distributed beamforming, regularized zero-forcing precoding, QR decomposition