Dual NAV Channel Access Mechanism for WLAN Bandwidth Utilization
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Solution Overview
Problem
The existing IEEE 802.11 wireless local area network (WLAN) system's virtual carrier sensing mechanism inefficiently manages channel transmission bandwidth, leading to interference and reduced frequency band utilization due to the use of a single Network Allocation Vector (NAV) for all subchannel frequency bands, causing stations to ignore small duration transmissions and resulting in unnecessary channel occupation.
Innovation Solution
Implementing two Network Allocation Vectors (NAVs) - intra-NAV and inter-NAV - on all subchannel frequency bands within a basic service set, where intra-NAV records the duration the BSS forbids data transmission and inter-NAV records the duration an overlapping BSS forbids data transmission, allowing stations to determine available frequency bands for data transmission based on current NAV values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single NAV is used to control data transmission on all subchannel frequency bands, then the channel access mechanism is simplified, but frequency band utilization is reduced and interference occurs
Solution Approach 1:
The patent divides the single NAV into two separate NAVs: intra-NAV for controlling data transmission within the same BSS, and inter-NAV for controlling data transmission from overlapping BSSs. This segmentation allows independent management of different frequency bands, enabling stations to accurately determine available channels and improve frequency band utilization while reducing unnecessary channel occupation
2Ease of manufacture
If a single NAV controls all subchannel frequency bands, then the mechanism is easier to implement, but data transmission interference increases
Solution Approach 1:
By segmenting the NAV into intra-NAV and inter-NAV, the patent enables precise control over different frequency bands. Stations can now independently manage transmission permissions for intra-BSS and inter-BSS communications, reducing data transmission interference while maintaining implementation feasibility through the structured two-NAV approach
3Reliability
If stations update NAV based on duration greater than current value, then channel protection is enhanced, but channel occupation becomes unnecessary and prolonged
Solution Approach 1:
The patent segments NAV management into intra-NAV and inter-NAV, allowing stations to update only the relevant NAV based on the source of the received frame. This prevents unnecessary NAV updates that would cause prolonged channel occupation, while still maintaining reliable channel protection through targeted NAV updates based on actual transmission needs
Solution Approach 2:
The patent applies different NAV update rules to different scenarios: intra-NAV is updated for frames within the same BSS, while inter-NAV is updated for frames from overlapping BSSs. This local differentiation ensures that channel protection is applied only where necessary, reducing unnecessary channel occupation while maintaining reliability
Data Source
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AI summary
Embodiments of the present invention disclose a data transmission protection method and apparatus. The method includes: receiving, by a station, a trigger frame sent by an access point in a basic service set BSS associated with the station; and selecting, from a channel transmission bandwidth of the BSS based on current values of at least two network allocation vectors NAVs that are set on a subchannel frequency band in the channel transmission bandwidth of the BSS, an available subchannel frequency band for data transmission to respond to the trigger frame. In the embodiments of the present invention, the current values of the at least two NAVs can be used to select the available subchannel frequency band for data transmission to respond to the trigger frame. This helps reduce interference in data transmission and improve frequency band utilization.