Rotatable Block-Controlled RIS: Bridging the Performance Gap to Element-Controlled Systems

The passive reconfigurable intelligent surface (RIS) requires numerous elements to achieve adequate array gain, which linearly increases power consumption (PC) with the number of reflection phases. To address this, this letter introduces a rotatable block-controlled RIS (BC-RIS) that preserves spectral efficiency (SE) while reducing power costs. Unlike the element-controlled RIS (EC-RIS), which necessitates independent phase control for each element, the BC-RIS uses a single phase control circuit for each block, substantially lowering power requirements. In the maximum ratio transmission, by customizing specular reflection channels through the rotation of blocks and coherently superimposing signals with optimized reflection phase of blocks, the BC-RIS achieves the same averaged SE as the EC-RIS. To counteract the added power demands from rotation, influenced by block size, we have developed a segmentation scheme to minimize overall PC. Furthermore, constraints for rotation power-related parameters have been established to enhance the energy efficiency of the BC-RIS compared to the EC-RIS. Numerical results confirm that this approach significantly improves energy efficiency while maintaining performance.

Static Power Consumption Modeling and Measurement of Reconfigurable Intelligent Surfaces

Reconfigurable intelligent surfaces (RISs) are anticipated to transform wireless communication in a way that is both economical and energy efficient. Revealing the practical power consumption characteristics of RISs can provide an essential toolkit for the optimal design of RIS-assisted wireless communication systems and energy efficiency performance evaluation. Based on our previous work that modeled the dynamic power consumption of RISs, we henceforth concentrate more on static power consumption. We first divide the RIS hardware into three basic parts: the FPGA control board, the drive circuits, and the RIS unit cells. The first two parts are mainly to be investigated and the last part has been modeled as the dynamic power consumption in the previous work. In this work, the power consumption of the FPGA control board is regarded as a constant value, however, that of the drive circuit is a variant that is affected by the number of control signals and its self-power consumption characteristics. Therefore, we model the power consumption of the drive circuits of various kinds of RISs, i.e., PIN diode-/Varactor diode-/RF switch-based RIS. Finally, the measurement results and typical value of static power consumption are illustrated and discussed.

Reconfigurable Intelligent Surface: Power Consumption Modeling and Practical Measurement Validation

Due to the ability to reshape the wireless communication environment in a cost- and energy-efficient manner, the reconfigurable intelligent surface (RIS) has garnered substantial attention. However, the explicit power consumption model of RIS and measurement validation, have received far too little attention. Therefore, in this work, we propose the RIS power consumption model and implement the practical measurement validation with various RISs. Measurement results illustrate the generality and accuracy of the proposed model. Firstly, we verify that RIS has static power consumption, and present the experiment results. Secondly, we confirm that the dynamic power consumption of the varactor-diode based RIS is almost negligible. Finally but significantly, we model the quantitative relationship between the dynamic power consumption of the PIN-diode based RIS and the polarization mode, controllable bit resolution, working status of RIS, which is validated by practical experimental results.