Phase Rotation Vector for MIMO Preamble PAPR Reduction
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Solution Overview
Problem
Current wireless communication systems, particularly WLANs, face challenges in achieving high data throughput while maintaining backward compatibility with legacy devices, especially in MIMO communications where phase rotation techniques can impact peak to average power ratio (PAPR) and carrier detection for legacy devices.
Innovation Solution
The implementation of a phase rotation vector and cyclic shift delay (CSD) applied to sub-band components of preambles in wireless communication devices to reduce PAPR across various fields of a frame, ensuring backward compatibility and efficient operation with both legacy and newer wireless communication devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If phase rotation techniques are applied to preambles in MIMO communications, then data throughput is improved, but carrier detection for legacy devices deteriorates
Solution Approach 1:
The preamble is divided into sub-band components, and phase rotation is applied selectively to specific sub-bands while leaving others unchanged. This segmentation allows the system to achieve PAPR reduction and improved data throughput through phase rotation in certain sub-bands, while maintaining carrier detection compatibility with legacy devices in other sub-bands.
Solution Approach 2:
Different phase rotation patterns are applied to different sub-band components of the preamble based on their specific characteristics and requirements. This local differentiation enables optimized PAPR control and data throughput enhancement in specific sub-bands while preserving backward compatibility in other sub-bands.
2Power
If phase rotation vector is applied to reduce PAPR, then peak to average power ratio is reduced, but compatibility with legacy devices deteriorates
Solution Approach 1:
The frequency spectrum is segmented into multiple sub-bands, and phase rotation is applied selectively to specific sub-bands. This allows PAPR reduction to be achieved in certain sub-bands while maintaining legacy compatibility in other sub-bands, thus balancing power optimization with backward compatibility.
Solution Approach 2:
Instead of applying phase rotation to the entire preamble uniformly, the invention applies phase rotation only to specific sub-band components where it is most beneficial for PAPR reduction. This partial application achieves sufficient PAPR control without excessively impacting legacy device compatibility.
Data Source
AI summary
Phase rotation for preambles within multiple user, multiple access, and/or MIMO wireless communications. An appropriately designed phase rotation vector and/or appropriately designed cyclic shift delays (CSDs) are applied to respective sub-band components of the preamble. With appropriately designed CSDs, certain fields within the preamble are not modified. For example, a legacy short training field (L-STF) of the preamble is not changed when using appropriately designed CSDs. The respective CSDs may be implemented as integer multiples of a common CSD (e.g., 0×CSD, 1×CSD, 2×CSD, etc. such that one of the values of such a CSD vector may be zero [0], another may be the common CSD itself, etc.). Also, by employing an appropriately designed phase rotation vector and integer multiples of a CSD to a preamble, the respective peak to average power ratio (PAPR) between different respective fields within the preamble may be minimized.