ITS Station Fair Resource Allocation for Channel Congestion
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Solution Overview
Problem
Current intelligent transportation systems (ITS) face challenges with channel congestion in IEEE 802.11p-based vehicular ad-hoc networks, leading to unreliable communication and safety applications, particularly in high vehicle density scenarios, due to unfair allocation of resources and trade-offs between message rate and modulation data rate.
Innovation Solution
A combined message rate and modulation data rate congestion control strategy (MD-DCC) that adjusts both parameters based on packet count and vehicle count to ensure fair resource allocation and maximize channel capacity, improving application reliability and awareness range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If message rate is increased to improve application reliability, then communication reliability is improved, but channel congestion increases leading to unfair resource allocation
Solution Approach 1:
The patent changes the parameter being controlled from message rate to modulation data rate. By adjusting the modulation data rate (e.g., from 6 Mbps to 12 Mbps or 24 Mbps) instead of changing message rate, the system increases channel capacity and application reliability without causing unfair resource allocation or channel congestion. This parameter substitution resolves the contradiction by finding a different control variable that achieves the desired reliability improvement without the negative side effects.
2Productivity
If modulation data rate is increased to maximize channel capacity, then channel capacity is improved, but awareness range decreases due to higher SINR requirements
Solution Approach 1:
The patent implements dynamic adjustment of modulation data rate based on real-time channel conditions (CBP measurements). The system can switch between different modulation data rates (6 Mbps, 12 Mbps, 24 Mbps) depending on the congestion level. When channel conditions are good, higher data rates are used to maximize capacity; when congestion increases, the system dynamically lowers the data rate to maintain awareness range. This dynamic adaptation resolves the contradiction by allowing the system to optimize both channel capacity and awareness range based on current conditions.
Data Source
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AI summary
An intelligent transportation system (ITS) station (400) for a vehicle (200) is described. The ITS station (400) includes a packet count and vehicle count estimator (342) arranged to receive broadcast ITS transmissions from a plurality of neighbouring vehicles and provide an indication of a number of the plurality of vehicles and a number of packets received from the plurality of neighbouring vehicles; and a fair resource allocator circuit (410) operably coupled to the packet count and vehicle count estimator (342) and configured to adjust a broadcast message rate and a modulation data rate of an ITS transmission in a cooperative manner based on application reliability requirements, the number of the plurality of vehicles and the indication of the number of received packets; and a transmitter operably coupled to the fair resource allocator circuit (410) and configured to broadcast at least one ITS message using the adjusted broadcast message rate and adjusted modulation data rate. In this manner, an ITS station is provided that may improve and support application reliability requirements, such as safety applications.