WLAN CTS Duration Setting for Accurate TXOP Sharing NAV
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Solution Overview
Problem
Existing WLAN systems face challenges in efficiently managing network allocation vectors (NAV) during transmission opportunities (TXOP) sharing, leading to unnecessary NAV settings by non-participating stations, which can impact network performance.
Innovation Solution
The method involves detecting a clear-to-send (CTS) frame for TXOP sharing, identifying its duration field value, and setting the NAV accordingly, while the access point sets the CTS frame duration field to match the allocation duration, ensuring accurate NAV settings for participating stations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the CTS frame duration field is set to the full TXOP duration, then participating STAs can correctly set their NAV for the entire transmission opportunity, but non-participating OBSS STAs will incorrectly set unnecessary NAV blocking them from accessing the channel
Solution Approach 1:
The patent segments the NAV duration information by creating different duration field values for different STA groups. Participating STAs receive the full TXOP duration in the CTS frame's duration field, while non-participating OBSS STAs receive a shortened duration value that expires before the TXOP ends, allowing them to access the channel after their allocated time slot.
Solution Approach 2:
The patent applies local quality by providing different duration information quality to different STA types. The CTS frame contains duration information tailored to each STA's participation status - full duration for participating STAs needing complete TXOP protection, and reduced duration for non-participating STAs that should be able to access the channel after their time slot.
2Productivity
If the CTS frame duration field is set to a reduced value, then non-participating OBSS STAs can access the channel after their allocated time, but participating STAs may not have sufficient NAV protection for the complete TXOP duration
Solution Approach 1:
The patent segments the duration information delivery mechanism by using different interpretation rules for different STA groups. The same CTS frame structure carries duration information that participating STAs interpret as full TXOP protection duration, while non-participating STAs interpret as their specific time slot duration based on their allocation.
Solution Approach 2:
The patent introduces the CTS frame as an intermediary that carries differentiated duration information. The duration field in the CTS frame acts as a mediator that provides appropriate NAV setting values to different STA types, resolving the conflict between protecting participating STAs and enabling non-participating STA access.
3Ease of operation
If all STAs set NAV based on the CTS frame duration field, then the channel access control is simple and uniform, but it causes unnecessary channel blocking for non-participating STAs
Solution Approach 1:
The patent makes the CTS frame duration field universal by designing it to serve multiple functions simultaneously. The same duration field provides correct NAV protection for participating STAs while also providing appropriate time-limited protection for non-participating STAs, eliminating the need for different frame formats or additional signaling.
Solution Approach 2:
The patent applies parameter changes by modifying how the duration field value is interpreted based on STA type. The actual duration value in the CTS frame changes depending on whether the receiving STA is participating or non-participating in the TXS, allowing a single parameter to achieve differentiated behavior.
Data Source
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AI summary
The present disclosure relates to setting a network allocation vector (NAV) in a wireless local area network (LAN) system. According to an embodiment of the present disclosure, a method performed by a station (STA) in a wireless LAN system comprises the steps of: detecting a clear to send (CTS) frame for a transmission opportunity (TXOP) sharing (TXS) trigger frame including information about an allocation period within a TXOP period; identifying a value of a duration field of the CTS frame; and setting the NAV during the allocation period on the basis that the value of the duration field of the CTS frame is set to a value corresponding to the allocation period.