1. Cooperative Reflection Design With Timing Offsets in Distributed Multi-RIS Communications
- Author
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Wei Xu, Yaqiong Zhao, Derrick Wing Kwan Ng, Xiaohu You, and Huan Sun
- Subjects
Signal Processing (eess.SP) ,FOS: Computer and information sciences ,Reflection (computer programming) ,Offset (computer science) ,Computer science ,business.industry ,Computer Science - Information Theory ,Information Theory (cs.IT) ,Phase (waves) ,Communications system ,Improved performance ,Control and Systems Engineering ,Wireless communication systems ,Synchronization (computer science) ,FOS: Electrical engineering, electronic engineering, information engineering ,Electronic engineering ,Wireless ,Electrical Engineering and Systems Science - Signal Processing ,Electrical and Electronic Engineering ,business - Abstract
This letter investigates a wireless communication system deploying distributed reconfigurable intelligent surfaces (RISs). Existing works have assumed that perfect timing synchronization is available among all the cooperative RISs. For practical considerations, we first study cooperative reflection design for multi-RIS-aided communication systems taking into account timing synchronization errors. We aim to minimize the mean-squared error of the recovered data in the presence of timing offsets subject to the unit modulus constraints imposed on the phase shifts of the RISs. In order to handle this sophisticated nonconvex problem, we develop a computationally-efficient algorithm based on the majorization-minimization framework where the RIS phase shift matrices and the timing offset equalizer are respectively developed in a semi-closed form and a closed form. Numerical examples validate the improved performance of our proposed design compared with various schemes.
- Published
- 2021