Wireless Mesh Access Point Backoff Time Prioritization
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Solution Overview
Problem
In wireless mesh networks, the shared radio channel leads to an imbalance in channel capacity distribution among access points, causing data packets to accumulate and potentially result in data loss due to insufficient access to the channel, particularly in upstream and downstream traffic directions.
Innovation Solution
Implementing a traffic prioritization method where access points in the mesh network calculate a backoff time based on their current state, with nodes closer to the root and having more packets to transmit receiving a higher rank and thus a shorter backoff time, ensuring timely data transmission and preventing queue overflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If access points use a shared radio channel for mesh network communication, then device complexity is reduced and ease of operation is improved, but channel capacity distribution becomes imbalanced causing data accumulation and potential data loss
Solution Approach 1:
The patent changes the backoff time parameter dynamically based on the access point's position in the mesh network and its current traffic load. Access points closer to the root or with heavier loads use shorter backoff times, while those farther away or with lighter loads use longer backoff times. This parameter adjustment balances channel access distribution and prevents data accumulation without requiring complex hardware modifications.
2Productivity
If access points closer to the root obtain more channel capacity, then downstream traffic efficiency is improved, but upstream traffic from distant nodes suffers from data accumulation and loss
Solution Approach 1:
The patent applies different backoff time strategies to different access points based on their local conditions. Each access point calculates its own backoff time based on its specific position in the mesh and its current traffic state. This localized adjustment ensures that each node receives appropriate channel access priority for its specific needs, balancing overall network productivity with reliability at each local point.
3Device complexity
If access points use standard CSMA/CA backoff mechanism, then device complexity is minimized, but traffic prioritization capability is insufficient leading to packet accumulation
Solution Approach 1:
The patent implements a self-service mechanism where each access point autonomously calculates and adjusts its own backoff time based on its current state and position in the mesh network. No central controller or complex coordination protocol is needed - each node independently makes decisions to optimize traffic flow, maintaining low device complexity while achieving effective traffic prioritization and preventing packet accumulation.
Data Source
AI summary
Prioritizing traffic forwarding in a wireless mesh network. In a wireless mesh network using carrier detect multiple access—collision avoidance with backoff, such as mesh networks supporting IEEE 802.11 clients, access points in the mesh calculate a node rank based on downstream and upstream rank components. Access points in the mesh then generate backoff times inversely proportional to their node rank. This has the effect of prioritizing traffic at nodes that have higher rank. The downstream and upstream rank components take into account the amount of space occupied by downstream and upstream traffic, respectively, and are weighted by their position in the mesh tree.