Clear Channel Assessment Threshold Adjustment for Wireless Access
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Solution Overview
Problem
In high-density wireless networks with overlapping Basic Service Sets (BSS), the current Clear Channel Assessment (CCA) method is inefficient due to the same CCA threshold being applied to all traffic, leading to prolonged access procedures as transmissions from different networks contribute to the measured signal level.
Innovation Solution
Setting different CCA threshold values for intra-BSS and inter-BSS frames, where the wireless communications device adjusts the threshold based on whether the detected frame is intra-BSS or inter-BSS, allowing for a higher inter-BSS CCA threshold to determine channel idle conditions, thereby optimizing the backoff procedure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the same CCA threshold is applied to all sensed traffic in high-density overlapping BSS deployments, then the CCA procedure is simple to implement, but the access procedure is prolonged due to transmissions from different networks contributing to the measured signal level
Solution Approach 1:
The patent segments the CCA threshold into two distinct thresholds: one for intra-BSS traffic and another for inter-BSS traffic. This segmentation allows the system to differentiate between transmissions from the same network and transmissions from overlapping networks, enabling more efficient channel access decisions in high-density deployments without overly complicating the threshold management mechanism.
Solution Approach 2:
The patent applies local quality by setting different CCA threshold values based on the source of the transmission. Intra-BSS transmissions receive one threshold value while inter-BSS transmissions receive another. This localized differentiation optimizes channel access for each type of traffic independently, improving overall access procedure speed while maintaining manageable complexity through context-specific threshold application.
2Measurement precision
If the CCA threshold is lowered to detect all transmissions accurately, then the channel idle determination becomes more precise, but the backoff procedure is extended due to frequent busy channel detections from overlapping networks
Solution Approach 1:
The patent changes the CCA threshold parameter based on the BSS origin of detected frames. By adjusting the threshold value according to whether the frame is intra-BSS or inter-BSS, the system maintains high measurement precision for channel idle determination while avoiding unnecessary backoff extensions caused by transmissions from overlapping networks that should not block access.
3Measurement precision
If the device performs detailed frame decoding to distinguish intra-BSS and inter-BSS frames, then the CCA threshold selection becomes accurate, but the processing complexity and time increase
Solution Approach 1:
The patent performs preliminary action by decoding and identifying the BSS origin of frames during the backoff period before making CCA decisions. This preliminary identification allows the device to select the appropriate CCA threshold in advance, ensuring accurate frame type identification while reducing processing complexity and time during the critical channel access decision moment.
Data Source
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AI summary
Methods and apparatus are provided for clear channel assessment in the Wifi network. In one novel aspect, different clear channel assessment (CCA) threshold value is set for intra-BSS and inter-BSS frames during the counting down process. A CCA procedure senses the radio channel and determines if the radio channel is busy or idle during the backoff period by comparing the signal level value of detected fames with the CCA threshold value. The counting down will be suspended if the radio channel determined to be busy. If the detected frame is inter-BSS frame, the CCA threshold value is raised. If the signal level of the detected frames is lower than the inter-BSS CCA threshold for inter-BSS fames, the radio channel is considered idle. The counting down process is resumed.