Hybrid adaptive Beamforming Systems using programmable Metasurfaces

• Applicant: Professor Dr.-Ing. Thomas Zwick
• Subject Area: Electronic Semiconductors, Components and Circuits, Integrated Systems, Sensor Technology, Theoretical Electrical Engineering
• Term: from 2018 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 391994084

• Final Report Year: 2021

Final Report Abstract

In this project, systems based on PM beamforming have been demonstrated and analyzed. The proposed project goals and additional attractive ambitions discovered during the project are successfully achieved. The main contributions of the project can be concluded as follows, covering both scientific values and marketing demands. The first reflection type of reconfigurable PM operating at 28 GHz was designed, optimized, fabricated, and measured. It was proved that a PIN diode-based 1-bit reconfigurable PM generates optimum -60° to 60° beamforming along azimuth direction with 2° angle resolution. By implementing different beamforming strategies, various beamforming patterns could be managed to adapt to many types of communication scenarios. These built up the fundamental of the systems, and measurements for different channel estimation as well as beamforming algorithms experimented. In addition, the PM is controlled by a well-designed DC board and enables fast beam switching and beam steering, which was measured to be one of the fastest existing PM beam steerings. Therefore, advanced hybrid beamforming algorithms such as TDMA, real-time UE tracking can be implemented. These experiments were the first group of PM-based systems considering practical communication scenarios working at 28 GHz. In comparison to a phased array, the PM designed in this project has the advantage of low cost and power consumption. The PM which contains a hundred times more elements than a phased array can be fabricated with the same cost. This contributes to a better beamforming quality since the gain introduced by the larger number of antenna elements beats the degradation caused by the 1-bit phase resolution. Based on this evidence, if PMs can be widely implemented into the market, a large amount of price reduction can be attractive for the companies and governments. Thus, it is convincible that the PMs can play very important roles in the future wireless and mobile communication generations. As one of the most important achievements of this project, a hybrid MIMO beamforming system based on the designed PMs was demonstrated. Three PMs were used at the transmitter assuming BS, and multiple data streams fully occupying the bandwidth were propagated to the Rx, and recovered with nice SINR performance. This was realized by discovering novel channel estimation and hybrid beamforming algorithms adaptive for the PM-based hybrid beamforming system, which can be regarded as an important milestone. Different from the conventional phased array hybrid beamforming structures, channel state information between each unit cell on the PM at Tx and UE antennas at Rx cannot be derived. As a solution, beam training algorithms were firstly utilized to search for the optimum analog beamforming solution. Afterward, digital channel estimation algorithms took place to derive the effective MIMO channel matrix upon the optimized analog beamforming. According to the estimated channel, different hybrid beamforming algorithms to realize data propagation were finally managed and analyzed. By the end of this project, the first world-leading full PM-based hybrid MIMO beamforming testbed was established. With the availability and advantages of PM strongly proved, further creative algorithms and mobile communication scenarios can be discovered and realized.

Publications

• "A novel wireless communication system using programmable metasurface operating at 28 GHz." 2020 International Conference on Microwave and Millimeter Wave Technology (ICMMT). IEEE, 2020
  Li, Yueheng, et al.
  
• "Analog 28 GHz LoS MIMO Relay System Using a 90 Hybrid Coupler." IEEE Antennas and Wireless Propagation Letters 19.4 (2020): 571-575
  Eisenbeis, Joerg, et al.
  
• "MIMO communication measurements in small cell scenarios at 28 GHz" (2020)
  Eisenbeis, Joerg, et al.
  
• "A Programmable Metasurface Based TDMA Fast Beam Switching Communication System at 28 GHz." IEEE Antennas and Wireless Propagation Letters 20.5 (2021): 658-662
  Li, Yueheng, et al.
  
• "Beamsteering for 5G Mobile Communication Using Programmable Metasurface." IEEE Wireless Communications Letters (2021)
  Li, Yueheng, et al.
  
• "Ka-band Programmable Metasurface Demonstrations in Wireless Communication Scenarios." 2021 15th European Conference on Antennas and Propagation (EuCAP). IEEE, 2021
  Li, Yueheng, et al.
  
• "Reconfigurable sum and difference beams based on a binary programmable metasurface." IEEE Antennas and Wireless Propagation Letters 20.3 (2021): 381-385
  Wan, Xiang, et al.
  
• "Joint modulations of electromagnetic waves and digital signals on a single metasurface platform to reach programmable wireless communications." Engineering (2022)
  Wan, Xiang, et al.