Downlink Transmissions for Millimeter-Wave MIMO Networks with Reconfigurable Antenna Arrays
Master of Science
Millimeter-wave (mmWave) communication devices equip large antenna arrays which enable directional beamforming to combat the high pathloss. However, the hardware limitations in digital beamforming devices make analog processing of signals in RF domain, referred to analog beamforming, more attractive than the traditional digital beamforming. In this work, we analyze the network performance in two practical scenarios of mmWave networks. We develop an antenna array reconfiguration structure in the analog domain with low hardware complexity. We propose analog beamforming strategies to improve the spectral efficiency in a sparse network and to improve the coverage probability in a dense network. Such antenna structure and beamforming strategy can achieve higher performance in downlink transmissions to multiple end users than conventional antenna sub-array methods. The performance of the downlink network is evaluated via both theoretical analysis and simulations. The analytical and numerical results indicate the access points (APs) with the proposed structure and beamforming strategy can reach a performance close to the upper bound of the downlink network. The proposed transmission strategies can also achieve a considerable performance improvement in downlink transmissions to multiple end users than conventional antenna sub-array methods.
Millimeter-wave communication; Multiple-input multiple-output (MIMO); Analog beamforming; Reconfigurable antenna array