MAC Layer TFC Selection for Low-Priority QoS Guarantee
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Solution Overview
Problem
In UMTS mobile communication systems, existing methods for selecting transport format combinations often prioritize high-priority logical channels, leading to data starvation and poor quality of service for low-priority services, particularly in real-time applications like audio streaming.
Innovation Solution
The method involves selecting a transport format combination that prioritizes the minimum quality of service (QoS) requirements of each upper layer channel, ensuring that at least one low-priority service receives the necessary resources to prevent data starvation, by considering the QoS before transmission priority at the MAC layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If transport format combination is selected based on transmission priority of logical channels, then high-priority services are transmitted efficiently, but low-priority services experience data starvation and poor quality of service
Solution Approach 1:
The patent applies preliminary action by pre-configuring minimum QoS parameters for each logical channel before data transmission occurs. The MAC layer uses these pre-established minimum QoS requirements to ensure that low-priority services receive guaranteed resource allocation, preventing data starvation before it can occur during actual transmission.
Solution Approach 2:
The patent changes the selection parameter from transmission priority to minimum QoS requirements. By evaluating logical channels based on their minimum QoS parameters rather than just priority levels, the system adjusts resource allocation to guarantee a certain quality of service for all channels, including low-priority ones, while still allowing efficient transmission of high-priority services.
2Reliability
If transport format combination is selected to guarantee minimum QoS for all channels, then quality of service for low-priority services is maintained, but transmission efficiency may be reduced
Solution Approach 1:
The patent applies partial action by providing only the minimum necessary QoS guarantee for low-priority services rather than allocating maximum resources to all channels uniformly. The MAC layer calculates the minimum required resources to meet QoS parameters and allocates only that much, allowing high-priority services to use remaining resources efficiently without compromising low-priority service reliability.
Solution Approach 2:
The patent applies local quality by differentiating resource allocation based on individual channel requirements. Each logical channel receives QoS treatment tailored to its specific minimum requirements rather than uniform treatment. This allows the system to optimize transmission efficiency for high-priority channels while guaranteeing minimum quality for low-priority channels simultaneously.
3Device complexity
If the MAC layer considers only transmission priority for TFC selection, then the selection process is simple, but data starvation occurs for low-priority channels
Solution Approach 1:
The patent applies preliminary action by having the RRC layer pre-configure minimum QoS parameters for each logical channel before data transmission begins. This pre-configuration simplifies the MAC layer's decision-making process, as it only needs to compare actual data amounts against pre-established minimum QoS thresholds rather than implementing complex priority-based scheduling algorithms.
Solution Approach 2:
The patent introduces minimum QoS parameters as an intermediary between the simple priority-based selection process and the complex requirement for data starvation prevention. These intermediary parameters serve as decision thresholds that guide the MAC layer's TFC selection, balancing simplicity with reliability by providing clear, pre-defined criteria for resource allocation.
Data Source
AI summary
The present invention relates to selecting a transport format combination (TFC) such that a quality of service (QoS) is guaranteed in a mobile communication system of a certain level even for a service having a low priority. The present invention selects a transport format combination such that not only a priority of each service is guaranteed but also a service quality is guaranteed by an MAC layer at the time of transporting services having different QoSs and different priorities.