Wireless Station Medium Access Management via Dynamic Backoff
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High node density in wireless mesh networks, particularly those adhering to the IEEE 802.11s standard, leads to medium access congestion due to hidden nodes and uneven capacity distribution, where edge stations tend to overload their neighbors, necessitating additional congestion management beyond existing CSMA/CA protocols.
Innovation Solution
A method that generates a refraining time value based on the duration of previously transmitted frames, penalizing stations that transmit more frequently by preventing them from accessing the medium for a duration proportional to their previous transmissions, thereby reducing congestion and promoting cooperative behavior among neighboring stations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If CSMA/CA protocol with random backoff is used for medium access, then collision probability is reduced, but capacity disparity between edge and center stations increases due to hidden nodes
Solution Approach 1:
The patent implements a feedback mechanism where stations monitor their own transmission activity and adjust their backoff behavior accordingly. Specifically, stations that have transmitted frames recently are penalized with extended backoff periods, creating a feedback loop that prevents any single station from monopolizing the medium and thereby reduces capacity disparity in mesh networks
Solution Approach 2:
The patent introduces dynamic backoff adjustment where the backoff parameter is not fixed but varies based on recent transmission history. The backoff value is dynamically modified according to a penalty mechanism that considers the duration and frequency of recent transmissions, making the medium access behavior adaptive rather than static
2Productivity
If edge stations transmit frequently to maximize their own capacity, then their individual throughput increases, but congestion increases for neighboring center stations
Solution Approach 1:
The patent applies preliminary anti-action by preemptively penalizing stations before they can cause congestion to their neighbors. When a station transmits a frame, the system immediately imposes a backoff penalty that prevents the station from transmitting again too soon, thereby preventing potential congestion before it occurs
Solution Approach 2:
The patent changes the backoff parameter dynamically based on transmission history. Instead of using a fixed or purely random backoff value, the system adjusts the backoff parameter to include a penalty component that is proportional to recent transmission activity, thereby modifying the medium access timing to reduce neighbor congestion
Data Source
AI summary
The present invention relates to, in a wireless network in which wireless stations transmit frames, a method of managing the access of the medium to a wireless station once a frame or a sequence of frames has been transmitted by the wireless station, the method comprising: (a) generating a time value resulting from a function of the duration of the frame or the sequence of frames to be transmitted, —(b) transmitting the frame or the sequence of frames; and (c) after step (b), the wireless station refraining from access to the medium by counting down a refraining time, the value of the refraining time being determined by taking account of the said time value.