| dc.description.abstract | Compared with previous generations of communication systems, 5G puts forward higher requirements, faster speed, lower delay and better efficiency for communication systems. These requirements are all benefited from the application and development of Millimeter wave. But on the other hand, the huge transmission loss makes the communication quality drop significantly. Beamforming is a key technology to overcome the above-mentioned effects.In the hybrid beamforming architecture, the number of Radio Frequency chain determines the cost. The Radio Frequency chain are connected to each antenna through a phase shifter, which increases the complexity of hardware design, so the structure of partial connection is proposed that when the Radio Frequency chain is only connected to some antennas, but not fully connected
to all antennas, this architecture is called hybrid beamforming partial connection architecture. However, since the Radio Frequency chain is not connected to all antennas, the spectrum efficiency becomes low, and the accuracy of data transmission decreases. This is a hardware limitation. In this paper, we use a multi-path three-dimensional (3D) channel as the channel environment, and propose an algorithm combining partially connected beamforming algorithm and geometric mean decomposition(GMD), through the algorithm get its analog precoder and combiner, and then use GMD to optimize the part of the digital precoder and combiner, it can avoid complex bit allocation. Different from the traditional SVD-based hybrid precoding, it can convert the mmWave massive MIMO channel into the same sub-channel, so no additional allocation is needed, the design complexity of modulation and coding is reduced, and the partial connection system’s BER performance can be achieved with low complexity. In addition, we are also discussing the BER, and apply partial connected array optimization method connected to the RIS to see if it can have the same effect as the signal processing of the antenna array, and finally the simulation results are used for performance analysis and discussion. | en_US |