WLAN Preamble Beamforming Matrix Generation
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Solution Overview
Problem
Existing 802.11 wireless local area network (WLAN) standards face challenges in backward compatibility and performance due to their mixed format structure, requiring an adaptive transmission mechanism for preambles to accommodate both legacy and non-legacy portions.
Innovation Solution
The method involves transmitting a preamble with a first portion spanning multiple symbol durations via beamforming using a first beamforming matrix and a second portion spanning a single symbol duration, with its own beamforming matrix calculated based on the first, allowing for omni-directional or mixed transmission modes, and incorporating high efficiency training fields and cyclic delay/cyclic shift diversity for enhanced channel estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a mixed format preamble structure is used to maintain backward compatibility, then legacy compatibility is improved, but the complexity of the transmission mechanism increases due to needing to adapt to both legacy and non-legacy portions
Solution Approach 1:
The preamble is divided into two distinct portions: a legacy portion (L-STF, L-LTF, L-SIG) that maintains compatibility with traditional 802.11 standards, and a non-legacy portion (HE-STF, HE-LTF, HE-SIG) that enables advanced features. This segmentation allows each portion to be processed independently with appropriate beamforming strategies, reducing overall system complexity while maintaining compatibility.
Solution Approach 2:
The patent implements dynamic beamforming matrix generation where the second beamforming matrix for the non-legacy portion is generated based on the first beamforming matrix from the legacy portion. This dynamic adaptation allows the system to switch between different transmission modes (omni-directional or beamforming) for different preamble portions, simplifying the transmission mechanism while maintaining versatility.
2Reliability
If beamforming is applied to the second preamble portion, then channel performance is improved, but the complexity of generating and calculating beamforming matrices increases
Solution Approach 1:
The first beamforming matrix is calculated and applied to the legacy preamble portion first. This preliminary action provides a foundation that can be reused to generate the second beamforming matrix for the non-legacy portion, reducing the overall computational complexity while maintaining improved channel performance through beamforming.
Solution Approach 2:
The patent changes the parameter relationship between the two beamforming matrices by generating the second matrix based on the first matrix rather than calculating them independently. This parameter dependency reduces computational complexity while preserving the beamforming benefits for enhanced channel performance.
3Measurement precision
If separate beamforming matrices are used for each preamble portion, then transmission precision is improved, but the computational overhead increases
Solution Approach 1:
Instead of generating completely independent beamforming matrices for each preamble portion, the patent establishes a parameter relationship where the second beamforming matrix is derived from the first. This approach maintains transmission precision through separate matrix optimization while reducing computational overhead by leveraging the existing first matrix as a basis.
Data Source
AI summary
Some embodiments described herein provide a method for transmitting a preamble in accordance with a wireless local area network communication protocol. In some embodiments, a data frame may be obtained for transmission including a preamble compliant with the wireless local area network communication protocol. It may be determined that the preamble includes a first preamble portion that spans multiple symbol durations and a second preamble portion that spans a single symbol duration. The first preamble portion via beamforming may be transmitted based on a first beamforming matrix. When a transmission mode of the second preamble portion is beamforming, a second beamforming matrix may be generated based on the first beamforming matrix, each tone for the second preamble portion may be calculated based on the second beamforming matrix. Each calculated tone may be transmitted in accordance with the wireless local area network communication protocol.