Beam Scanning Codebook for mmWave Synchronization
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Solution Overview
Problem
In wireless communication systems, particularly those using mmWave frequencies, the beam scanning process between a base station and user equipment (UE) is complex and burdensome, leading to increased calculation complexity and signaling load for the UE, which complicates synchronization and cell ID acquisition.
Innovation Solution
A method involving the generation of a codebook with weighted sums of precoders, applied to synchronization signals transmitted over multiple time intervals, simplifies the beam scanning procedure by sharing the codebook between the base station and UE, reducing the need for additional signaling and sequence allocation, and utilizing orthogonal vectors based on Hadamard or DFT matrices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional beam scanning procedure is used in mmWave communication system, then synchronization signal can be transmitted to cover all terminals, but calculation complexity of UE increases and beam scanning becomes burdensome
Solution Approach 1:
The base station performs preliminary actions by generating a codebook of precoders and transmitting it to the UE before beam scanning. The codebook contains pre-calculated precoding vectors that the UE can directly use for beamforming, eliminating the need for the UE to perform complex real-time calculations during beam scanning. This preliminary preparation significantly reduces UE computational burden while maintaining synchronization reliability.
Solution Approach 2:
Instead of requiring the UE to independently calculate beamforming vectors, the invention uses a copying approach where the base station generates and transmits a codebook containing pre-computed precoding vectors. The UE copies these pre-calculated vectors from the codebook for use in beam scanning, avoiding redundant computational efforts and reducing device complexity while ensuring reliable synchronization.
2Ease of operation
If traditional beam scanning procedure is used, then beam scanning can be performed, but additional signaling load and sequence allocation are required
Solution Approach 1:
The invention merges the beam scanning function with the synchronization signal transmission by applying different precoders from the codebook to the synchronization signal across multiple time intervals. This combination allows beam scanning to be performed using the same signaling resources already allocated for synchronization, eliminating the need for separate beam scanning sequences and reducing overall signaling load.
Solution Approach 2:
The synchronization signal is designed to serve multiple functions simultaneously: it provides timing synchronization, frequency synchronization, cell ID identification, and beam scanning information. By making the synchronization signal universal and multi-functional, the invention eliminates the need for separate dedicated beam scanning signals, thereby reducing signaling overhead and information loss.
3Productivity
If codebook with weighted sums of precoders is used, then beam scanning efficiency is improved and UE complexity is reduced, but additional codebook generation and management is required
Solution Approach 1:
The codebook is segmented into multiple precoders, each corresponding to a specific beam direction or time interval. This segmentation allows the base station to manage and transmit only the necessary precoders for current beam scanning requirements, rather than managing a single large codebook. The UE similarly processes the segmented precoders in an organized manner, improving beam scanning efficiency while keeping codebook management tractable.
Solution Approach 2:
The codebook is transmitted periodically or at predetermined intervals to the UE, allowing both base station and UE to synchronize their codebook versions. This periodic update mechanism ensures that both parties have access to the latest precoding information without requiring continuous complex management protocols, thereby improving beam scanning efficiency while maintaining manageable codebook operations.
Data Source
AI summary
Disclosed are a beam scanning method and a base station, the method in which generated is a code book comprising a plurality of second precoders, defined by the weighted sums of a plurality of first precoders, and in which a plurality of synchronization signals, to which applied are second precoders that are selected from the code book and differ from each other, are transmitted to a terminal over a plurality of time intervals. The synchronization signals are used in synchronization, beam scanning and cell ID acquisition of the terminal, and each weighted sum applied to the plurality of first precoders indicates a beam ID used in the beam scanning.