Wireless Mesh Path Selection Using Channel Sounding
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Solution Overview
Problem
Existing methods for path selection in wireless mesh networks do not fully exploit the advantages of multiple path routing, leading to suboptimal performance in terms of throughput, packet error rates, and latency due to cumbersome and inaccurate airtime link metric estimation and outdated link quality statistics.
Innovation Solution
The proposed method involves an originating node receiving discovery signals from multiple possible transmission paths, estimating radio channels, calculating link metrics for different transmission modes, and transmitting these metrics to select optimized paths for simultaneous data transmission, allowing for better utilization of radio resources and improved throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If airtime link metric estimation is used for path selection, then routing decisions can be made, but the procedure becomes cumbersome and inaccurate leading to suboptimal performance
Solution Approach 1:
The patent applies preliminary action by performing channel sounding and link quality measurements before actual data transmission. The source node sends sounding packets to potential relay nodes and receives feedback, allowing the system to pre-establish accurate link metrics and select optimal paths before transmitting actual data, thereby avoiding cumbersome procedures during data transmission
Solution Approach 2:
The patent introduces an intermediary feedback mechanism where relay nodes send acknowledgment packets containing channel quality information back to the source node. This intermediary feedback serves as a mediator that provides accurate link metric information without requiring complex direct measurements between all node pairs, simplifying the overall path selection procedure
2Reliability
If link quality statistics are built from ACK/NACK messages, then routing information can be obtained, but the statistics become outdated quickly in dynamic networks reducing Quality of Service
Solution Approach 1:
The patent implements periodic action by having nodes send periodic channel sounding packets and update link quality metrics at regular intervals. This periodic refresh of channel information ensures that routing decisions are based on current link conditions rather than outdated statistics, maintaining Quality of Service in dynamic wireless networks
Solution Approach 2:
The patent performs preliminary channel sounding and link quality assessment before path selection, obtaining fresh channel state information through dedicated sounding packets. This preliminary measurement ensures that routing decisions are made based on current, accurate link quality data rather than relying on potentially outdated ACK/NACK statistics
3Productivity
If single path routing is used, then routing is simpler, but throughput is limited and packet error rates are higher
Solution Approach 1:
The patent applies segmentation by dividing the data transmission into multiple parallel paths through the network. Instead of using a single routing path, the system identifies and utilizes multiple disjoint paths from source to destination, segmenting the traffic flow to achieve higher aggregate throughput and better reliability through path diversity
Solution Approach 2:
The patent transitions from single-dimension routing to multi-dimensional routing by considering multiple paths simultaneously. The system evaluates routes based on multiple dimensions including link quality, path diversity, and available capacity, enabling throughput enhancement through spatial and temporal diversification of transmission paths
Data Source
AI summary
The proposed technology relates to path selection in wireless mesh networks. In particular the disclosure relates to methods for selection of one or more transmission paths from an originating node to a target node in a wireless mesh network, wherein there are at least two possible transmission paths between the originating node and the target node. More specifically, the disclosure proposes a method, performed in an originating node in a wireless network comprising several nodes wirelessly connected to each other, for enabling selection of a transmission path from the originating node to a target node, wherein there are at least two possible transmission paths between the originating node and the target node. The method comprises the steps of receiving SI discovery signals from nodes in the at least two possible transmission paths and estimating S2, based on the received discovery signals, radio channels H for transmission from the originating node to the nodes transmitting the discovery signals. The method further comprises calculating S3, for different transmission modes, based on the estimated radio channels, metrics of links from the originating node to the nodes transmitting the discovery signals, wherein at least one of the transmission modes involves simultaneous transmission from the originating node to at least two of the nodes transmitting the discovery signals and transmitting S4 the calculated metrics to an adjacent node. The disclosure also relates to the corresponding apparatuses and computer programs.