RIS Precoding Codebooks for Beamforming Around Signal Blockage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing wireless communication systems, particularly in NR and LTE, face challenges in improving mobile broadband access and beamforming efficiency due to obstacles blocking communication between transmitters and receivers, necessitating enhanced techniques for beam management and signal reconfiguration.
Innovation Solution
The implementation of a reconfigurable intelligent surface (RIS) with a codebook-based precoding system that adjusts phase shifts and amplitudes of RIS elements using a controller to optimize beamforming, enabling communication through obstacles by generating and applying codebooks based on feedback from transmitters and receivers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional beamforming is used in wireless communication systems, then communication between transmitter and receiver is established, but communication is blocked by obstacles such as buildings and hills
Solution Approach 1:
The patent introduces a reconfigurable intelligent surface (RIS) as an intermediary device deployed between the transmitter and receiver. The RIS reflects and redirects radio waves around obstacles, enabling communication paths that bypass blockages. This mediator approach allows signals to navigate through urban environments with buildings and hills that would traditionally block direct line-of-sight communication.
Solution Approach 2:
The RIS employs dynamic reconfigurability with controllable meta-atoms that can adjust their electromagnetic properties in real-time. The system dynamically adapts beamforming configurations based on channel conditions, enabling the communication system to respond to changing obstacle positions and environmental factors, thereby maintaining reliable communication despite dynamic blockage conditions.
2Productivity
If RIS elements are controlled with full precoding capability, then beamforming efficiency is improved, but system complexity increases
Solution Approach 1:
The RIS is divided into multiple independent controllable meta-atoms or elements that can be individually controlled. Each meta-atom can be independently configured with specific phase and amplitude shifts, allowing the system to achieve sophisticated beamforming by coordinating simple individual elements rather than requiring complex monolithic control.
Solution Approach 2:
The patent implements codebook-based precoding where only a subset of RIS elements need to be actively controlled at any given time, rather than requiring all elements to be fully precoded simultaneously. This partial action approach reduces the instantaneous complexity requirements while maintaining the ability to achieve high beamforming efficiency when needed by activating only the necessary elements for a particular beam direction.
Data Source
AI summary
Aspects of the present disclosure relate to techniques, methods, devices, systems, and non-transitory computer readable medium for generating codebooks for reconfigurable intelligent surfaces (RIS) s. For example, a RIS controller generates a codebook for a RIS by computing weights using a discrete Fourier transform (DFT) function or a fractional Fourier transform (FrFT) function, based on reference signals (RSs) transmitted by a transmitter. The weights correspond to the RIS elements or a subset of the RIS elements. In some aspects, the computation of the weights may include oversampling factors that allow for a higher resolution of the weights and improved search for an optimal precoding setting. Different sets of weights may be used for different incoming beams. The RIS controller may be trained with a pair of transmitter and a receiver to identify/generate the codebook for an optimized set of weights under specific situations.