Wi-Fi PHY Header Segmentation for Extended Outdoor Range
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Solution Overview
Problem
The physical layer header in next-generation WLAN (IEEE 802.11ax) is a bottleneck for outdoor applications, leading to reduced range and reliability of Wi-Fi signals compared to LTE-U, and existing designs like DensiFi's high-efficiency SIGNAL field (SIG) do not adequately address this issue.
Innovation Solution
Enhancements to the physical layer header include boosting signal power through repetition, dividing the header into segments for individual encoding, increasing cyclic prefix duration, and using more powerful encoding schemes like concatenated convolutional codes to reduce overhead and improve reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the physical layer header is used in current Wi-Fi networks, then signal transmission can be maintained with legacy compatibility, but the range is limited and reliability is reduced due to overhead
Solution Approach 1:
The physical layer header is divided into multiple segments, each encoded and transmitted separately. This segmentation reduces the overhead impact on any single transmission and improves reliability through diversity, as different segments can be received and decoded independently to reconstruct the complete header information.
Solution Approach 2:
The cyclic prefix duration is increased beyond the standard value to mitigate intersymbol interference. This parameter change extends the protection interval between symbols, allowing the signal to maintain integrity over longer propagation distances and improving overall signal reliability in extended range conditions.
2Length of moving object
If signal power is increased through repetition techniques, then range is extended, but overhead increases
Solution Approach 1:
Instead of repeating the entire header, the header is segmented and only critical portions are repeated across multiple transmissions. This selective repetition extends range through power diversity while minimizing the total overhead quantity by avoiding redundant transmission of all header bits.
Solution Approach 2:
The patent applies partial repetition by transmitting only essential header segments multiple times rather than the full header. This partial action is sufficient to extend range and ensure reliable decoding of critical information while keeping the total overhead quantity lower than full header repetition would require.
3Reliability
If cyclic prefix duration is increased to mitigate intersymbol interference, then signal reliability is improved, but transmission efficiency decreases
Solution Approach 1:
The header is segmented into multiple parts, each with its own cyclic prefix. This allows the cyclic prefix to be optimized for each segment's specific requirements rather than applying a uniformly long prefix to the entire header, thereby maintaining reliability while improving overall transmission efficiency.
Solution Approach 2:
The cyclic prefix duration is selectively increased only for segments that require enhanced protection against intersymbol interference, rather than uniformly increasing it for all segments. This selective parameter change maintains signal reliability where needed while preserving transmission efficiency in segments that can tolerate shorter prefixes.
Data Source
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AI summary
Example systems, methods, and devices for extending range of WiFi networks are discussed. More specifically, methods for extending range of a Wi-Fi network are disclosed. The method may include the operations of appending, by a network device, one or more codebits to one or more original codebits or coded symbols, sending, by the network device, the original codebits or coded symbols and the appended codebits to an interleaver or a constellation mapper for transmission. The original codebits or coded symbols and the appended codebits may be sent over a plurality of subcarriers. Methods, apparatus, and systems described herein can be applied to 802.1 lax or any other wireless standard.