RIS Phase-Shift Codebook Precoding for Low-Complexity Beam Reflection
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Solution Overview
Problem
Existing joint precoding designs for reconfigurable intelligent surfaces (RIS) and base stations are overly complex and less applicable in practice.
Innovation Solution
A method for determining a phase shift list for an RIS array, involving quantization and sorting of phase shift sequences to reflect incident signals along specific reflection angles, allowing for low-complexity and high-applicability precoding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If joint precoding design at RIS and base station uses alternate optimization technologies, then precoding can be achieved, but the system complexity becomes overly complex and applicability decreases
Solution Approach 1:
The patent segments the joint precoding design into two independent parts: base station precoding matrix selection and RIS phase shift selection. The base station selects from a codebook of pre-defined matrices while the RIS selects from a codebook of phase shift sequences, eliminating the need for complex joint optimization while maintaining precoding effectiveness through independent codebook-based selection.
2Manufacturing precision
If conventional joint precoding design is implemented, then signal reflection control is achieved, but the implementation complexity increases and practical applicability decreases
Solution Approach 1:
The patent applies preliminary action by pre-defining codebooks at both the base station and RIS. The base station maintains a codebook of precoding matrices and the RIS maintains a codebook of phase shift sequences corresponding to different reflection angles. This pre-prepared structure enables direct selection rather than real-time optimization, achieving precise signal reflection control while greatly simplifying implementation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enhances signal strength and transmission performance at user equipment by reflecting signals along optimal angles, simplifying the precoding process while maintaining effectiveness.
Implementation Method 1
each row of phase shift sequence is configured to cause the RIS array to reflect an incident signal along a pair of reflection angles
Implementation Method 2
the phase shift sequence includes a phase shift of each RIS array element in the RIS array
Data Source
AI summary
A precoding method, performed by a reconfigurable intelligent surface (RIS) array, includes determining a phase shift list corresponding to the RIS array, in which the phase shift list includes at least one row of phase shift sequence, the phase shift sequence includes a phase shift of each RIS array element in the RIS array, each row of phase shift sequence is configured to cause the RIS array to reflect an incident signal along a pair of reflection angles, and each row of phase shift sequence corresponds to one index value; acquiring a first index value from a user equipment (UE); determining a first phase shift sequence corresponding to the first index value from the phase shift list; and precoding the RIS array by configuring the phase shift of each RIS array element in the RIS array according to the first phase shift sequence.