Wireless Rate Adaptation via Packet Delay and Loss Limits
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Solution Overview
Problem
Existing rate adaptation methods for wireless multimedia applications prioritize throughput over packet delay and loss, leading to poor video playback quality due to high packet loss ratios, especially in real-time video streaming, as they favor higher transmission rates despite high packet loss, resulting in video mosaic and artifacts.
Innovation Solution
Implementing a rate adaptation method that selects a packet transmission rate based on packet delay and loss parameters, calculating a packet retry limit and transmission loss rate limit for each supported rate, and adjusting the rate if the current loss rate exceeds the set limit, thereby minimizing packet loss and improving video playback quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If rate adaptation methods select higher transmission rates to maximize throughput, then throughput is improved, but packet loss ratio increases significantly
Solution Approach 1:
The patent changes the selection criteria parameter from throughput-only to a composite metric that includes both throughput and packet loss ratio. The rate selection metric is defined as a function of both throughput and packet loss ratio, causing the system to select different transmission rates based on current channel conditions and application requirements
Solution Approach 2:
The patent implements dynamic rate selection where the system continuously monitors packet loss ratio and adjusts the transmission rate accordingly. The rate adaptation mechanism dynamically switches between higher rates (when packet loss is acceptable) and lower rates (when packet loss exceeds threshold), making the system adaptable to changing channel conditions
2Productivity
If rate adaptation methods favor higher transmission rates, then channel utilization is improved, but video playback quality deteriorates due to excessive packet loss
Solution Approach 1:
The patent introduces a new selection metric that incorporates video quality requirements as a parameter. The rate selection process evaluates both channel utilization and packet loss impact on video quality, selecting rates that maintain acceptable playback quality while utilizing the channel effectively
Solution Approach 2:
The patent performs preliminary evaluation of different transmission rates by estimating their impact on packet loss and video quality before actual transmission. The system predicts which rates will maintain acceptable video playback quality and pre-selects appropriate rates before video streaming begins
3Speed
If packet transmission rate is increased, then data transmission speed is improved, but packet loss ratio increases leading to video artifacts
Solution Approach 1:
The patent implements a feedback mechanism where the system monitors actual packet loss ratio and transmission performance, then uses this feedback to adjust future rate selections. The rate adaptation algorithm learns from past performance and modifies its rate selection strategy to avoid rates that cause excessive packet loss and video artifacts
Data Source
AI summary
A wireless communication device, such as a wireless router or access point, transmits and receives signals according any one of several standard or proprietary wireless protocols and automatically adapts its transmission rate according to the condition of a link or channel over which it is sending and receiving signals. A packet delay value is used to calculate the maximum number of packet retransmissions that are acceptable given a particular application. The packet retransmission value is used to calculate a maximum acceptable packet loss value which is then compared against actual packet losses to determine whether or not to change the packet transmission rate. If it is determined that the actual packet losses are less than the maximum acceptable value, then the packet transmission rate can be changed to a higher rate and if it is determined that the actual packet losses are greater than the maximum acceptable value, then the packet transmission rate can be changed to be a lower rate.