Wireless VoIP Rate Shifting via RSSI and Retry Rate
Solution Overview
Problem
Existing rate shifting algorithms for Wireless Voice over IP (WVoIP) struggle to differentiate between packet errors caused by poor channel conditions and network overload, leading to inefficient rate adaptation and network performance degradation.
Innovation Solution
A method that differentiates between poor channel conditions and heavy network load by using a combination of retry rate and received signal strength indication data to adapt rate shifting, incorporating a transition period to minimize false shifting and support multiple rates and thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If retry based rate shifting is used, then packet error rate is reduced in poor channel conditions, but network congestion increases in heavily loaded networks
Solution Approach 1:
The patent introduces RSSI (Received Signal Strength Indication) as an intermediary parameter to distinguish between poor channel conditions and network overload. By combining retry rate with RSSI measurements, the system can identify whether packet errors are caused by channel quality or network congestion, and only trigger rate down-shifting when channel conditions actually warrant it, thereby avoiding unnecessary throughput reduction in congested networks.
Solution Approach 2:
The patent changes the parameters used for rate shifting decisions from solely retry-based metrics to a combined approach using both retry rate and RSSI. This parameter change enables the system to differentiate between the two causes of packet errors and make more accurate rate adaptation decisions, resolving the contradiction between reducing packet errors and maintaining throughput.
2Reliability
If rate shifting is triggered conservatively, then packet error rate is reduced, but network throughput decreases
Solution Approach 1:
The patent implements dynamic rate shifting that adapts to real-time channel conditions using RSSI measurements. Instead of conservative fixed thresholds, the system dynamically adjusts rate decisions based on current signal strength and retry patterns, allowing it to maintain high throughput when conditions permit while providing reliable error reduction when channel quality degrades.
3Productivity
If rate shifting is triggered aggressively, then network throughput is improved, but packet error rate increases
Solution Approach 1:
The patent employs feedback mechanisms that continuously monitor both retry rates and RSSI values to evaluate the effectiveness of rate shifting decisions. This feedback loop allows the system to learn from past decisions and adjust future rate changes accordingly, achieving aggressive throughput optimization without sacrificing packet error performance through data-driven adaptive control.
Data Source
AI summary
A method of rate shifting specially suited for the voice traffic, which differentiates poor channel conditions from a heavily loaded channel of a WLAN and adapts to the network traffic condition and channel condition promptly with low rate of false shifting. Determining when to rate shift is based on a combination of the received signal strength indication and the retry rate.