Short Bio:
Xiaoming Chen received the B.Sc. degree in electrical engineering from Northwestern Polytechnical University, Xi’an, China, in 2006, and M.Sc. and Ph.D. degrees in electrical engineering from Chalmers University of Technology, Gothenburg, Sweden, in 2007 and 2012, respectively. From 2013 to 2014, he was a postdoctoral researcher at the same University. From 2014 to 2017, he was with Qamcom Research & Technology AB, Gothenburg, Sweden. Since 2017, he has been a professor at Xi’an Jiaotong University, Xi’an, China. His research areas include MIMO antennas, over-the-air testing, reverberation chambers. He has published more than 150 journal articles on these topics. Prof. Chen currently serves as a Senior Associate Editor for IEEE Antennas and Wireless Propagation Letters. He was the general chair of the IEEE International Conference on Electronic Information and Communication Technology (ICEICT) in 2021. He won the first prize of universities’ scientific research results in Shaanxi province, China, 2022. He received the IEEE outstanding Associate Editor awards 2018, 2019, 2020, 2021, and 2022, and URSI (International Union of Radio Science) Young Scientist Award 2017 and 2018.
Title: Simultaneous Decoupling and Decorrelation for MIMO Performance Enhancement in Realistic Multipath Environment for Access Point Applications
Abstract:
The MIMO system is a crucial technology to cope with the high capacity demand of the fourth-generation (4G) and fifth-generation (5G) communication. To avoid grating lobes, the inter-element spacing of the MIMO array is usually no larger than half-wavelength, resulting in high mutual couplings and high correlations. Various decoupling techniques have been proposed. It is common believed that low coupling ensured low correlation, however, this is incomplete and this misconcept will be discussed in this talk. In realistic multipath scenarios with limited angular spread (AS), two antennas separated by half-wavelength can still be highly correlated. This is especially true for MIMO arrays at base stations (BS) or access points (AP), where the angular spread is usually much smaller than that at the user equipment. By placing several phase correcting elements (PCE) at different heights over the array, the near-field phase distribution is modified to resemble that of an array with larger inter-element separation, as shown in Fig. 1. To reduce the multi-layer complexity, an improved decorrelation method is proposed, where the equivalent phase centers of the array elements is stretched by placing a single-layer scatterer array consisting of PCEs in front of the MIMO array, leading to reduced correlations (cf. Fig. 2). The latter method can be tuned to be compatible for some existing decoupling technique. As a result, a joint decoupling and decorrelation method will be proposed in this talk. The MIMO arrays are designed, fabricated, tested. The results show a significant improvement of the MIMO performances in realistic multipath scenarios for BS/AP applications.
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