Credit-Based Packet Scheduling for Fair Resource Allocation
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Solution Overview
Problem
In mobile communication systems, especially UMTS and LTE uplink transmissions, existing scheduling methods lead to starvation of lower priority bearers during high cell load conditions due to inefficient resource allocation, which restricts flexibility and fairness in capacity assignment among bearers.
Innovation Solution
A credit-based packet scheduling method where each bearer is assigned a positive credit in each time period, allowing data packet acceptance based on priority, buffer content, and credit constraints, with excess credit carried forward as negative credit to ensure whole packet transmission and minimize segmentation, ensuring fair resource allocation and meeting minimum bit-rate criteria.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If highest priority first scheduling is used, then transmission efficiency is improved, but lower priority bearers suffer from starvation
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing the minimum transmission requirement for each bearer before scheduling. The scheduler retrieves these pre-computed values during resource allocation, enabling efficient decision-making without real-time complex calculations, thus maintaining high transmission efficiency while ensuring lower priority bearers receive their guaranteed minimum resources
Solution Approach 2:
The patent changes the scheduling parameter from simple priority-based selection to a composite parameter that includes both priority level and pre-calculated minimum transmission requirement. This parameter transformation allows the scheduler to balance between high-priority bearers needing fast transmission and low-priority bearers needing minimum resource guarantees, resolving the starvation problem while maintaining overall efficiency
2Adaptability or versatility
If per-bearer resource allocation is implemented, then resource assignment flexibility is improved, but system complexity increases
Solution Approach 1:
The patent segments the resource allocation process into two independent parts: (1) pre-calculation of minimum transmission requirements for each bearer, and (2) scheduling decision based on priority and pre-computed values. This segmentation allows flexible per-bearer resource assignment while simplifying the actual scheduling operation, as the complex calculations are done beforehand and stored for quick retrieval
Solution Approach 2:
By performing preliminary calculation of minimum transmission requirements before the scheduling phase, the patent reduces the complexity of real-time scheduling decisions. The scheduler only needs to compare pre-computed values and priority levels, rather than performing complex resource allocation calculations during each scheduling interval, thus maintaining flexibility without proportionally increasing system complexity
Data Source
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AI summary
A method of scheduling packets in a mobile communication system comprises, in each time period, assigning to each bearer of a terminal, a credit. In each time period for which resources are available, accepting data packets from a bearer in accordance with predefined constraints of priority, buffer content and credit. An accepted data packet size may exceed the available credit by an amount in a predefined range.