Simultaneous Multiple Connections and Increased Frequency Efficiency Using Beam Squint Approach for IRS-Based Communication

• Published in: IEEE transactions on vehicular technology Vol. 73; no. 11; pp. 17073 - 17082
• Main Authors: Kawamoto, Yuichi, Tanaka, Ei, Verma, Shikhar, Kato, Nei, Iwabuchi, Masashi, Ohmiya, Riku, Ramamoorthi, Yoghitha, Murakami, Tomoki
• Format: Journal Article
• Language: English
• Published: IEEE 01-11-2024
• Subjects: 6G mobile communication; Bandwidth; beam squint; beamwidth expansion; frequency allocation; Frequency control; intelligent reflecting surface (IRS); Mathematical models; OFDM; Radio spectrum management; Reflection
• ISSN: 0018-9545; 1939-9359
• DOI: 10.1109/TVT.2024.3424856

Intelligent reflecting surfaces (IRSs) have attracted attention for realizing ultrahigh-speed and large-capacity communication in the next-generation 6 G communication standard. Still, research has indicated that it is difficult for an IRS to communicate simultaneously with multiple users. Therefore, the common method for communication via IRSs is to allocate a wide bandwidth to one user to perform large-volume communication in a short period per user and to support the communication of many users by repeating the same process. However, allocating broadband to a single user causes a reflected beam shift owing to the beam squint, reducing the frequency efficiency. Therefore, we propose a control and frequency allocation method for IRSs that can support multiple users simultaneously without reducing the frequency efficiency by effectively utilizing a beam squint. Specifically, the proposed method maximizes the frequency efficiency by controlling the IRS reflection direction, reflected beam width, and resource block allocation to user equipment (UE), exploiting the shift in the reflection direction caused by the beam squint. In this study, we evaluated the proposed method with regard to frequency efficiency and simultaneous multiple-connection performance through simulations.