Wireless NACK Avoidance for Broadcast Reliability
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Solution Overview
Problem
Broadcast transmissions in wireless networks, such as those used in Cooperative Intelligent Transport Systems, face scalability issues with Hybrid Automatic Repeat Request (HARQ) and Adaptive Modulation and Coding (AMC) mechanisms due to excessive feedback messages, leading to network performance degradation and reduced spectral efficiency.
Innovation Solution
A method where wireless communication devices await data packets and determine context information to control the transmission of negative acknowledgment indicators (NACK) and channel quality indicators (CQI) based on this information, reducing unnecessary feedback and retransmissions by only sending feedback if retransmission is useful, thereby minimizing network load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If HARQ and AMC mechanisms are used in broadcast transmissions, then transmission reliability is improved, but network load increases due to excessive feedback messages
Solution Approach 1:
The patent applies partial action by implementing HARQ mechanisms selectively rather than universally. Context-aware receivers determine whether to send feedback based on application-specific requirements, channel conditions, and QoS parameters. This partial application of feedback reduces the overall quantity of feedback messages while maintaining reliability for critical transmissions, directly resolving the contradiction between transmission reliability and network load.
Solution Approach 2:
The patent changes the parameter of feedback transmission from a fixed binary state (send/don't send) to a dynamic state based on multiple context parameters including application QoS requirements, channel quality indicators, receiver buffer status, and traffic patterns. This parameter-based adaptation allows the system to optimize the balance between reliability and network load by adjusting feedback behavior according to real-time conditions.
2Reliability
If robust modulation and coding settings are used in broadcast transmissions, then transmission reliability is improved, but spectral efficiency decreases
Solution Approach 1:
The patent introduces dynamics into the modulation and coding selection process by making it adaptive based on channel conditions and application requirements. Instead of using fixed robust settings for all broadcast transmissions, the system dynamically adjusts modulation order and coding rate based on channel quality feedback and QoS requirements, allowing optimal spectral efficiency while maintaining necessary reliability levels.
Solution Approach 2:
The patent changes the transmission parameters (modulation scheme, coding rate) from fixed to variable based on context information. Receivers provide channel quality indicators and the transmitter adapts modulation and coding parameters accordingly, enabling the system to achieve high spectral efficiency when channel conditions permit while maintaining reliability when conditions deteriorate.
3Reliability
If feedback messages are transmitted by all receivers, then transmission reliability is improved, but network performance degrades due to feedback storm
Solution Approach 1:
The patent implements partial feedback action where only a subset of receivers transmit feedback messages based on context-aware criteria. Application-layer logic determines which receivers should provide feedback based on their reception status, QoS requirements, and application-specific needs. This selective feedback approach maintains reliability for critical applications while preventing feedback storms that would degrade overall network performance.
Solution Approach 2:
The patent introduces an intermediary feedback mechanism where receivers first assess their reception status and channel conditions before deciding to transmit feedback. The feedback transmission is mediated by context evaluation logic that filters out unnecessary feedback messages, allowing the system to maintain reliability through essential feedback while preventing network performance degradation from excessive feedback traffic.
Data Source
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AI summary
The invention discloses a method for receiving a data packet from a first communication device by a second communication device in a wireless network comprising the following steps: - awaiting the data packet at the second communication device; determining a context information related to the data packet by the second communication device; if the data packet is not received successfully, controlling transmission of a negative acknowledgement indicator, NACK, and/or transmission of a channel quality indicator, CQI, by the second communication device to the first communication device based on the context information.