Wireless LAN Channel Access via Segmented Backoff Windows
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional WLAN systems face congestion issues when multiple Stations (STAs) access the medium simultaneously, particularly in scenarios like power outages or disasters, leading to inefficient channel access and increased power consumption.
Innovation Solution
A method and apparatus for STAs in a wireless communication system that involves performing carrier sensing and a random backoff procedure, where the starting point of the backoff is randomly selected from a range determined by a parameter, allowing for distributed channel access and reducing congestion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple STAs access the medium simultaneously using conventional random backoff, then channel access is enabled, but congestion occurs and power consumption increases
Solution Approach 1:
The contention window is divided into multiple sub-contention windows, each STA selecting a specific sub-window based on its ID. This segmentation distributes STAs across different time slots, reducing simultaneous access attempts and improving channel access efficiency while lowering power consumption through reduced collisions and retransmissions.
Solution Approach 2:
Each STA is assigned a specific sub-contention window based on its local ID, creating localized access opportunities. This local quality differentiation ensures that STAs with different IDs access the medium at different times, resolving the congestion problem while maintaining fair access for all STAs.
2Loss of time
If the contention window size is reduced to improve access speed, then channel access time decreases, but collision probability increases
Solution Approach 1:
By segmenting the contention window into sub-contention windows and assigning STAs to specific segments based on their IDs, the system reduces channel access time within each sub-window while maintaining low collision probability through distributed access patterns. The segmentation ensures that even with smaller window sizes, collisions are minimized because STAs are spread across multiple time slots.
3Quantity of substance
If a large number of STAs are supported for M2M communication, then network coverage increases, but medium access congestion worsens
Solution Approach 1:
The contention window is segmented into multiple sub-contention windows, and each STA is assigned to a specific sub-window based on its ID. This allows a large number of STAs to be supported simultaneously while maintaining efficient channel access, as STAs are distributed across different time slots rather than competing in a single crowded window.
Solution Approach 2:
The system introduces a temporal dimension to channel access by creating multiple sub-contention windows in time. This dimensional expansion allows numerous STAs to access the medium efficiently by distributing them across different time slots, transforming a one-dimensional contention problem into a multi-dimensional access scheme.
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
A method for gaining access according to one embodiment of the present invention in which a station (STA) gains access to a medium in wireless communication system comprises the steps of: sensing a carrier wave for a medium so as to transmit a set frame; and, if the medium is busy, executing a random back-off procedure, wherein the starting point of the random back-off procedure is indicated by a second parameter randomly selected from within a range in accordance with a first parameter.