Early Indication for High Efficiency Fields in Wireless Systems
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Solution Overview
Problem
In high-efficiency wireless communication systems like IEEE 802.11ax, existing methods for determining the presence and repetition of high-efficiency signal fields (HE-SIG-A and HE-SIG-B) are inefficient, leading to delays in automatic gain control (AGC) settings and potential loss of signal quality due to the need for additional time to detect constellation types.
Innovation Solution
The proposed solution involves using an early indication bit and constellation type detection within the legacy signal field to determine the presence and repetition of HE-SIG-A and HE-SIG-B fields, allowing devices to adjust AGC settings and enhance decoding reliability by signaling this information through the length field and constellation mapping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional methods are used to detect constellation types and determine HE-SIG-A/HE-SIG-B fields, then detection accuracy can be maintained, but decoding time increases and signal quality deteriorates due to delays in AGC settings
Solution Approach 1:
The patent applies preliminary action by using the legacy signal field (L-SIG) to provide early indication of the HE-SIG-A repetition factor and HE-SIG-B presence before the actual high-efficiency fields are transmitted. The length field in L-SIG is repurposed to carry indication bits that enable receiving devices to predict the structure of upcoming HEW preamble fields, allowing AGC settings and decoding preparation to occur in advance, thus reducing overall decoding time while maintaining detection accuracy
2Reliability
If additional time is allocated for constellation type detection, then detection reliability improves, but signal quality is lost due to delays in AGC adjustments
Solution Approach 1:
The patent enables preliminary AGC adjustments by providing early indication of field structure through the L-SIG length field. Receiving devices can prepare their AGC settings in advance based on the indication bits, eliminating delays in AGC adjustments and preventing signal quality loss while maintaining detection reliability
Solution Approach 2:
The patent uses the legacy signal field (L-SIG) as an intermediary to convey information about the HE-SIG-A repetition factor and HE-SIG-B presence. This intermediary approach allows the system to communicate critical structure information without requiring additional detection time during the actual high-efficiency field transmission, thus maintaining signal quality while ensuring reliable detection
3Productivity
If the length field is used to carry indication bits for early detection, then decoding efficiency improves, but the field's original function may be compromised
Solution Approach 1:
The patent applies multi-functionality by enabling the L-SIG length field to serve dual purposes: maintaining its original function of indicating packet length information while simultaneously carrying indication bits for HE-SIG-A repetition factor and HE-SIG-B presence. This allows the same field to provide both traditional length information and early structural indication, improving decoding efficiency without compromising the original field function
Solution Approach 2:
The patent changes the interpretation parameters of the length field by repurposing specific bit patterns to indicate HE-SIG-A repetition factors (1, 2, or 4) and HE-SIG-B presence. This parameter change allows the field to convey additional structural information while maintaining backward compatibility, as receiving devices can interpret the length field according to the new encoding scheme without requiring separate indication fields
Data Source
AI summary
This disclosure describes methods, apparatus, and systems related to early indication system. A device may identify a high efficiency frame in accordance with a high efficiency communication standard, received from a first device, the high efficiency frame including, at least in part, one or more legacy signal fields and one or more high efficiency signal fields. The device may determine a length field included in one of the one or more legacy signal fields, wherein the length field includes an indication bit. The device may determine a position of a high efficiency short training field within the high efficiency frame based at least in part on the indication bit.