WLAN TXOP Duration Signaling Under HE-SIGA Bit Limits
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Solution Overview
Problem
The existing WLAN standards, particularly 802.11ax, face challenges in efficiently indicating the remaining channel usage time (TXOP duration) due to limited bit allocation in HE-SIGA, leading to performance degradation and inefficiencies in channel access policies.
Innovation Solution
Implementing a method to indicate TXOP duration in HE-SIGA with multiple granularities, using 6 or 7 bits to provide more precise channel usage time indications, allowing for multi-level TXOP units such as 8 μs, 16 μs, 32 μs, and 512 μs, and applying rules to avoid over-protection or under-protection issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the TXOP duration is indicated using a fixed number of bits in HE-SIGA, then the channel access policy can be implemented, but the precision and flexibility of TXOP duration indication is limited
Solution Approach 1:
The TXOP duration indication is segmented into multiple fields: a first indication field for coarse granularity indication and a second indication field for fine granularity indication. This segmentation allows the system to achieve high precision without requiring an excessively large total number of bits, as each segment handles a specific range or precision level.
Solution Approach 2:
The patent introduces a granularity indication field that adds an additional dimension to the TXOP duration indication. Instead of using a single large-bit field, the system uses multiple smaller fields where one field indicates the granularity level and another field provides the actual duration value at that granularity, effectively transforming a one-dimensional precision problem into a two-dimensional solution space.
2Measurement precision
If more bits are allocated to indicate TXOP duration, then the precision of channel usage time indication improves, but the overhead in HE-SIGA increases
Solution Approach 1:
The patent implements partial indication by using a granularity field that selectively activates different precision levels. When fine granularity is not required, the system uses only the coarse indication field, avoiding the overhead of transmitting unnecessary fine-granularity bits. This partial action approach ensures that precision is provided only when and where needed, reducing overall signal overhead.
3Adaptability or versatility
If a single granularity is used for TXOP duration indication, then the implementation is simpler, but the adaptability to different channel access scenarios is reduced
Solution Approach 1:
The patent makes the indication mechanism dynamic by introducing a granularity indication field that can switch between different granularity levels (e.g., 8 μs, 16 μs, 32 μs, 512 μs). This dynamic adaptation allows the system to adjust the precision and range of TXOP duration indication based on the specific channel access scenario, providing high versatility while maintaining manageable complexity through structured field definitions.
Data Source
AI summary
An example method for indicating a transmission opportunity (TXOP) duration in a wireless communication system is provided. The method includes generating, by a TXOP holder, a physical layer protocol data unit (PPDU). The PPDU includes a TXOP duration field. The TXOP duration field indicates remaining time for using a channel by the TXOP holder. The TXOP duration field includes a first part which indicates a granularity indicating the remaining time, and a second part which indicates the TXOP duration using the granularity indicated by the first part. The method further includes sending, the generated PPDU.