LTF Symbol Generation for 16-Stream WLAN Throughput
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Solution Overview
Problem
Conventional IEEE 802.11ax standard is limited in supporting a maximum of 8 streams, which restricts the peak throughput and requires an increased number of LTF symbols as streams increase, leading to inefficiencies in channel estimation and communication.
Innovation Solution
An enhanced LTF generation scheme that uses a P mapping matrix to generate LTF symbols for odd and even-numbered streams, allowing for up to 16 streams with a reduced number of LTF symbols compared to conventional methods, maintaining orthogonality between streams and improving channel estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of streams is increased beyond 8, then the peak throughput is improved, but the number of LTF symbols must be greatly increased
Solution Approach 1:
The patent divides the stream handling into two separate generation sequences: a first LTF generation sequence for odd-numbered streams and a second LTF generation sequence for even-numbered streams. This segmentation allows the system to efficiently manage up to 16 streams without requiring a proportional increase in LTF symbols, as each sequence can be reused across multiple streams of its respective type.
Solution Approach 2:
The patent creates universal generation sequences that can serve multiple streams. The first LTF generation sequence is universally applied to all odd-numbered streams (1st, 3rd, 5th, etc.), and the second LTF generation sequence is universally applied to all even-numbered streams (2nd, 4th, 6th, etc.). This multi-functionality reduces the total number of unique LTF symbols needed while supporting increased stream counts.
2Productivity
If the number of streams is increased, then the communication capacity is improved, but the channel estimation complexity increases
Solution Approach 1:
The patent segments the channel estimation process by creating separate generation sequences for odd and even streams. This segmentation simplifies the estimation complexity for each individual sequence while enabling the system to handle up to 16 streams total, as receivers can process odd and even streams independently using their respective sequences.
3Ease of manufacture
If conventional LTF generation scheme is used, then implementation is simple, but it supports only limited number of streams (maximum 8)
Solution Approach 1:
The patent maintains implementation simplicity by using a segmented approach with only two generation sequences instead of creating unique sequences for each stream. The segmentation into odd and even streams allows the system to support up to 16 streams while keeping the generation process straightforward and manageable.
Solution Approach 2:
The patent introduces dynamic adaptability by making the LTF generation scheme flexible enough to support variable stream counts up to 16. The system can dynamically select and apply the appropriate generation sequence based on whether the stream is odd or even numbered, enabling versatile stream support without complex reconfiguration.
Data Source
AI summary
This specification is related to a long training field (LTF) symbol of a WLAN. The LTF symbol may be generated based on a first LTF generation sequence used for an odd-numbered stream and a second LTF generation sequence used for an even-numbered stream. An even-numbered element of the first LTF generation sequence may be set to zero (0), and an odd-numbered element of the second LTF generation sequence may be set to zero (0). A plurality of LTF symbols for first and third streams may be generated by applying a P mapping matrix to the first LTF generation sequence. A plurality of LTF symbols for a second stream may be generated by applying the P matrix to the second LTF generation sequence.