Link-Latency Adaptive Retransmission in Wireless Mesh Networks
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Solution Overview
Problem
Existing wireless mesh networks face issues with frame collisions and inefficient retransmission due to mismatched backoff windows and frame lifetimes that do not account for varying link latencies, leading to repetitive collisions, delays, and network congestion.
Innovation Solution
Adaptive techniques that adjust backoff times and frame lifetimes based on the link latency of neighboring nodes, using equations to determine appropriate values for each individual link, thereby optimizing communication efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If uniform backoff times and frame lifetimes are used across all links, then device complexity is reduced and ease of operation is improved, but network efficiency deteriorates due to mismatches with varying link latencies causing collisions and congestion
Solution Approach 1:
The patent applies local quality by configuring different backoff times and frame lifetimes for different communication links based on their specific latency characteristics. Each radio link is analyzed individually, and transmission parameters are optimized locally for that specific link rather than applying uniform settings across all links, thereby resolving the contradiction between operational simplicity and network efficiency.
Solution Approach 2:
The patent implements dynamics by making backoff times and frame lifetimes adaptive rather than static. The system continuously monitors link latency and dynamically adjusts transmission parameters in response to changing network conditions, allowing the network to maintain high efficiency while automatically adapting to varying link characteristics without requiring manual reconfiguration.
2Reliability
If aggressive retransmission attempts are made to improve reliability, then frame delivery success is improved, but network congestion increases due to excessive retransmissions
Solution Approach 1:
The patent applies parameter changes by adjusting backoff times and frame lifetimes based on measured link latency characteristics. For links with higher latency, the system increases backoff times to avoid collisions and extends frame lifetimes to allow sufficient time for successful delivery, thereby maintaining reliability without generating excessive congestion. This dynamic parameter adjustment ensures retransmission behavior is optimized for each specific link condition.
3Reliability
If longer frame lifetimes are used to allow more retransmission attempts, then reliability is improved, but loss of time increases due to extended transmission windows
Solution Approach 1:
The patent resolves this contradiction by dynamically adjusting frame lifetimes based on link latency measurements. Rather than using uniformly long frame lifetimes for all links, the system configures frame lifetimes proportional to the specific latency characteristics of each link. This ensures that frames are given sufficient time for successful delivery on high-latency links while avoiding unnecessary time extension on low-latency links, thereby maintaining reliability without excessive time loss.
Data Source
AI summary
Various embodiments disclose a method comprising determining, by a first node, a first link latency associated with a second node based on a time period between consecutive slots in a unicast listening schedule for the second node; in response to the first node detecting a failure in transmitting a first frame to the second node, determining, by the first node based on the first link latency, a first backoff time; and in response to determining that the first backoff time has elapsed, retransmitting, by the first node, the first frame to the second node.