1. From ORAN to Cell-Free RAN: Architecture, Performance Analysis, Testbeds and Trials
- Author
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Cao, Yang, Zhang, Ziyang, Xia, Xinjiang, Xin, Pengzhe, Liu, Dongjie, Zheng, Kang, Lou, Mengting, Jin, Jing, Wang, Qixing, Wang, Dongming, Huang, Yongming, You, Xiaohu, and Wang, Jiangzhou
- Subjects
Signal Processing (eess.SP) ,FOS: Computer and information sciences ,Computer Science - Information Theory ,Information Theory (cs.IT) ,FOS: Electrical engineering, electronic engineering, information engineering ,Electrical Engineering and Systems Science - Signal Processing - Abstract
Open radio access network (ORAN) provides an open architecture to implement radio access network (RAN) of the fifth generation (5G) and beyond mobile communications. As a key technology for the evolution to the sixth generation (6G) systems, cell-free massive multiple-input multiple-output (CF-mMIMO) can effectively improve the spectrum efficiency, peak rate and reliability of wireless communication systems. Starting from scalable implementation of CF-mMIMO, we study a cell-free RAN (CF-RAN) under the ORAN architecture. Through theoretical analysis and numerical simulation, we investigate the uplink and downlink spectral efficiencies of CF-mMIMO with the new architecture. We then discuss the implementation issues of CF-RAN under ORAN architecture, including time-frequency synchronization and over-the-air reciprocity calibration, low layer splitting, deployment of ORAN radio units (O-RU), artificial intelligent based user associations. Finally, we present some representative experimental results for the uplink distributed reception and downlink coherent joint transmission of CF-RAN with commercial off-the-shelf O-RUs.
- Published
- 2023
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