由于高的传输损耗和CMOS功放的能力限制，60GHz系统常采用天线阵波束成形技术，来满足在要求的距离范围内的链路预算要求。然而，现在60GHz波束成形的研究还很不成熟，有待深入，因此本项目将聚焦于60GHz系统中的波束成形研究。 本项目研究内容包括： (1) 低复杂度数字、模拟、数模混合波束成形。另外，还将改进现有的码书以提高性能。 (2) EIRP受限的波束成形。通过直接考虑EIRP限制，研究最优的或者次优的波束成形方法。 (3) 自适应子阵选择。在天线阵元很多而射频链路很少的情况下，在实际中常使用自适应子阵选择。将考虑60GHz系统的硬件限制，应用压缩感知来研究低复杂度的自适应子阵选择方法。 (4) 考虑射频非理想性的波束成形。由于CMOS限制，60GHz射频模块容易受到非理想性的影响。将研究射频非理想性对波束成形系统的影响；另外，将研究波束成形和射频非理想性估计/补偿的联合处理

Due to the high path loss and limited capability of CMOS power amplifier, 60GHz systems often adopt antenna array beamforming to meet the link budget requirement at desirable distances. So far, however, the 60GHz beamforming technology is far from mature and thus needs further investigation. In view of this, this project will focus on 60GHz beamforming technology. The project contents include the following parts: (1) Low-complexity digital beamforming, analog beamforming, hybrid digital and analog beamforming. Moreover, the exsiting codebooks for 60GHz systems will be modified to increase the performance. (2) EIRP constrained beamforming. By explicitly considering EIRP constraint, we will present optimal、suboptimal beamforming solutions. (3) Adaptive sub-array selection. In scenarios where there are a large number of antenna elements but a small number of RF chains, adaptive sub-array selection technique is often used in practice. We will take into account hardware complexity limitation in 60GHz systems, exploit compressed sensing to address low-complexity adaptive sub-array selection methods. (4) beamforming incorporating RF imperfections. Due to the limitation of CMOS process, 60GHz RF components easily suffer from impairments. We will investigate the effect of RF imperfections on the beamformed 60GHz systems. Furthermore, we will address joint processing for the determination of beamforming vectors and the estimation/compensation of RF impairments.