Vehicle HARQ Retransmission Control for Changing Network Coverage
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Solution Overview
Problem
The inefficiency and wastage of slots for Hybrid Automatic Repeat Request (HARQ) retransmissions in vehicles due to motion-induced changes in network coverage, leading to unnecessary communication resource usage.
Innovation Solution
A system employing a telematics unit and command unit that dynamically adjusts HARQ retransmission frequency and response time based on vehicle situational parameters, including location, navigation status, and signal strengths, optimizing communication protocols for vehicles and vehicle groups.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the HARQ protocol is used for data transmission in moving vehicles, then data transfer reliability is improved through automatic retransmission requests, but communication slot efficiency deteriorates due to frequent unnecessary retransmissions
Solution Approach 1:
The system dynamically adjusts HARQ retransmission parameters based on real-time vehicle situational parameters. The command unit determines desirable values for retransmission frequency and response time by evaluating current location, navigation status, and signal strength, transforming the static HARQ protocol into an adaptive system that optimizes retransmission behavior according to vehicle motion state and communication conditions
Solution Approach 2:
The invention changes key parameters of the HARQ protocol including retransmission frequency, response time, and slot allocation based on vehicle situational parameters. By modifying these parameters dynamically rather than using fixed protocol settings, the system achieves both reliable data transfer and efficient communication slot utilization
2Reliability
If retransmission frequency is increased to ensure reliable data delivery, then data transfer reliability is improved, but network congestion increases and communication slots are wasted
Solution Approach 1:
The system implements a feedback mechanism where the command unit continuously monitors vehicle situational parameters and communication outcomes. Based on this feedback, the system adjusts retransmission frequency and response time to achieve reliable data delivery while avoiding excessive retransmissions that would cause network congestion
Solution Approach 2:
The retransmission frequency is dynamically adjusted based on real-time evaluation of vehicle location, signal strength, and navigation status. This dynamic adaptation ensures reliable data delivery when needed while reducing retransmissions in favorable conditions, thereby preventing network congestion
3Reliability
If the vehicle remains stationary to improve signal reception and reduce errors, then data transfer reliability is improved, but vehicle operational efficiency deteriorates
Solution Approach 1:
The command unit performs preliminary evaluation of vehicle situational parameters including current location, navigation status, and signal strength before initiating data transmission. This preliminary assessment allows the system to predict communication quality and adjust retransmission parameters in advance, ensuring reliable data transfer without requiring the vehicle to stop
Solution Approach 2:
The system dynamically adapts HARQ parameters based on real-time vehicle motion state and communication conditions. By adjusting retransmission frequency and response time according to vehicle speed and signal quality, the system maintains reliable data transfer while allowing continuous vehicle operation
4Reliability
If retransmission response time is extended to allow for multiple attempts, then data transfer reliability is improved, but communication latency increases
Solution Approach 1:
The response time parameter is dynamically adjusted based on vehicle situational parameters and communication conditions. The command unit determines desirable response time values that balance reliability requirements with latency constraints, adapting the timing parameters to match current operational context
Solution Approach 2:
The system changes response time parameters of the HARQ protocol based on evaluated vehicle situational parameters. By modifying these parameters dynamically rather than using fixed timing, the system achieves reliable data transfer with minimized latency
Data Source
AI summary
A system of managing communications in a vehicle includes a telematics unit connected to the vehicle. The telematics unit is configured to execute a retransmission request protocol upon receipt of erroneous data. A command unit in communication with the telematics unit, the command unit having a processor and tangible, non-transitory memory on which instructions are recorded. The command unit is adapted to determine vehicle situational parameters at a beginning of a data communication cycle. The vehicle situational parameters including current location and navigation status of the vehicle. When a first retransmission according to the retransmission request protocol is detected, the vehicle situational parameters are updated. The command unit is adapted to determine a desirable value of a retransmission frequency for the retransmission request protocol based in part on the updated vehicle situational parameters. In one embodiment, the retransmission request protocol is Hybrid Automatic Repeat Request (HARQ).