Fractional Fourier Transform Encoding for Uplink Flexibility
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Solution Overview
Problem
Current wireless communication systems face limitations in flexibility and payload size due to the use of discrete Fourier transform (DFT) encoding techniques, particularly in high Doppler scenarios where DFT encoding becomes less effective.
Innovation Solution
The implementation of fractional Fourier transform (FrFFT) encoding techniques by user equipment (UE) to encode uplink messages, allowing for more flexibility and improved performance by rotating the Fourier transform by an angle parameter (alpha value), which can be selected or indicated by the base station, enabling better handling of high Doppler conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If DFT encoding techniques are used, then implementation complexity is kept simple, but flexibility and payload size are limited
Solution Approach 1:
The patent applies parameter changes by introducing an angle parameter (alpha) that rotates the Fourier transform. This allows the encoding scheme to adapt to different channel conditions and Doppler scenarios while maintaining the same basic FrFFT structure. The angle parameter can be adjusted to optimize performance for different payload sizes and channel characteristics, thereby improving flexibility without substantially increasing implementation complexity.
2Quantity of substance
If DFT encoding techniques are used, then implementation complexity is kept simple, but payload size is limited
Solution Approach 1:
The FrFFT encoding with adjustable angle parameter enables larger payload sizes by providing additional degrees of freedom in the encoding process. The angle parameter can be optimized based on the payload size and channel conditions, allowing the system to accommodate more data while maintaining implementation complexity similar to conventional DFT encoding.
3Reliability
If DFT encoding is used, then the encoding process is simple, but performance in high Doppler scenarios deteriorates
Solution Approach 1:
The patent introduces the angle parameter (alpha) that can be adjusted to optimize performance in high Doppler scenarios. By rotating the Fourier transform by this angle, the FrFFT encoding adapts to the channel conditions caused by high Doppler shifts, improving transmission quality and reliability while maintaining encoding complexity at a level similar to conventional DFT encoding.
4Adaptability or versatility
If FrFFT encoding with angle parameter is used, then flexibility and transmission quality are improved, but implementation complexity increases
Solution Approach 1:
The FrFFT encoding scheme uses parameter changes (angle rotation) to achieve flexibility and improved transmission quality. The angle parameter can be selected from a predefined set or dynamically adjusted based on channel conditions, allowing the system to adapt without substantially increasing implementation complexity compared to conventional DFT encoding.
Data Source
AI summary
Methods, systems, and devices for wireless communications are described. Generally, a user equipment (UE) may identify an angle parameter for encoding uplink messages using a fractional Fourier Transform (FrFFT). A base station may transmit a set of angle parameters or a single angle parameter that the UE is to use for encoding an uplink message. The UE may select an alpha value from the set of alpha values for the encoding. The UE may transmit an indication of a set of proposed angle parameters to the base station, and the base station may determine and indicate one of or a subset of the received set of proposed angle parameters to the UE. The base station may indicate a correspondence between angle parameters and beam configurations, and the UE may identify an alpha parameter value based on a subsequently indicated beam configuration.