ACM Link Management When Receiver Feedback Fails
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing communication systems face challenges in managing variable-rate wireless communication links, particularly when feedback information from receivers is unusable due to channel conditions or equipment failures, leading to inefficiencies and potential data loss.
Innovation Solution
The implementation of Adaptive Coding and Modulation (ACM) systems that select Forward Error Correction (FEC) codes and modulation schemes based on feedback information, with the ability to switch to alternative ACM profiles independently or jointly across communication links to maintain link quality and meet Quality-of-Service (QoS) constraints, and temporarily disabling subsets of ACM profiles to ensure reliable data transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If feedback-based ACM profile selection is used to adapt data rate, then communication efficiency is improved, but system reliability deteriorates when feedback becomes unusable due to channel conditions or equipment failures
Solution Approach 1:
The transmitter maintains a predefined set of ACM profiles and selects an initial profile before feedback becomes unavailable. This preliminary preparation allows the system to continue operating with a predetermined configuration rather than waiting for feedback or shutting down, thus maintaining reliability during feedback failures while preserving the efficiency benefits of feedback-based adaptation when feedback is available
Solution Approach 2:
The transmitter autonomously switches to a different ACM profile independently of receiver feedback when feedback becomes unusable. This self-service mechanism allows the transmitter to maintain communication continuity by making its own decisions about profile selection based on local conditions, eliminating dependency on potentially failing feedback channels while preserving adaptability
2Productivity
If the transmitter continuously monitors and adapts ACM profiles based on feedback, then data rate optimization is improved, but system complexity increases due to feedback processing requirements
Solution Approach 1:
The system extracts and processes only the essential feedback information (reception quality metric) rather than processing complete feedback messages. When feedback becomes unusable, the system discards the problematic feedback processing path and switches to autonomous profile selection, thereby reducing the complexity burden during failure conditions while maintaining optimization capabilities when feedback is available
Solution Approach 2:
The feedback processing mechanism is made dynamic by switching between two modes: feedback-driven ACM profile selection when feedback is available and usable, and autonomous profile selection when feedback is unavailable or unusable. This dynamic adaptation allows the system to optimize data rate when possible while avoiding complex feedback processing when it would add unnecessary complexity or fail
3Adaptability or versatility
If multiple ACM profiles are maintained for adaptive modulation, then adaptability to channel conditions is improved, but device complexity increases due to multiple configuration options
Solution Approach 1:
The ACM configuration space is segmented into a predefined set of discrete profiles, each representing a specific combination of coding and modulation parameters. This segmentation allows the system to maintain multiple adaptability options while managing complexity through structured organization - the transmitter stores profiles in a defined structure and selects from predefined combinations rather than managing continuous parameter spaces
Solution Approach 2:
The system manages complexity by changing discrete parameters (ACM profile indices) rather than continuously adjusting multiple parameters simultaneously. When switching between profiles, the system changes a set of parameters as a unit (coding rate, modulation scheme, constellation size) according to predefined configurations, thereby maintaining adaptability to various channel conditions while reducing the complexity of parameter management through structured parameter changes
Data Source
AI summary
A method for communication includes transmitting data from a transmitter to a receiver using Adaptive Coding and Modulation (ACM). The data rate is set by selecting, based on feedback, an ACM profile defining a Forward Error Correction code and a modulation scheme. Upon detecting that the feedback is unusable, an operation of the transmitter is changed independently of the feedback.In another method, data is exchanged over two opposite directions of a bidirectional link that uses ACM by communicating using two ACM profiles. A joint constraint is defined on the two directions. The two ACM profiles are set based on first and second measured reception quality metrics of the two link directions, to meet the joint constraint. In yet another method, a subset of the ACM profiles is temporarily disabled, and the data is transmitted using only the ACM profiles that are not disabled.