Channel Access Priority Selection for LTE Uplink
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Solution Overview
Problem
In Licensed-Assisted Access (LAA) systems, the current method of selecting the lowest Channel Access Priority Class (CAPC) for uplink transmissions in LTE Autonomous Uplink (AUL) leads to degradation of Quality of Service (QoS) for data with higher CAPC priorities, resulting in increased transmission latency and inefficient use of configured grants.
Innovation Solution
A mapping mechanism and a selection mechanism are introduced to select a subset of data units for multiplexing into a data packet based on their channel access priorities, using a threshold priority to determine whether to select higher or lower CAPC priorities, thereby optimizing the channel access and improving transmission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the lowest CAPC priority is selected for multiplexed data units, then the channel access probability increases, but the QoS of high-priority data deteriorates
Solution Approach 1:
The patent segments data units by their CAPC priorities and creates separate handling paths. High-priority data units are segmented from low-priority ones, allowing different CAPC selection strategies for different data types. This segmentation enables the system to maintain high QoS for urgent data while still achieving reasonable channel access probability through separate transmission opportunities for lower priority data.
Solution Approach 2:
The patent introduces dynamic CAPC selection based on the composition of multiplexed data units. Instead of always selecting the lowest CAPC, the system dynamically adjusts the selected CAPC priority based on whether high-priority data is present. When high-priority data units are multiplexed, the system dynamically selects a higher CAPC priority to protect QoS, whereas when only low-priority data is present, it selects lower CAPC to maximize channel access probability.
2Productivity
If multiple data units with different CAPC priorities are multiplexed into one packet, then the transmission efficiency improves, but the QoS differentiation is lost
Solution Approach 1:
The patent applies local quality by allowing different CAPC priorities to coexist within the same transmission system with differentiated handling. Each data unit retains its original CAPC priority characteristics locally, and the system selects an appropriate representative CAPC for the multiplexed packet based on the presence of high-priority data. This ensures that high-priority data receives appropriate channel access treatment while still benefiting from multiplexing efficiency.
Solution Approach 2:
The patent performs preliminary classification and assessment of data units before multiplexing. The system evaluates the CAPC priorities of all data units intended for multiplexing and pre-determines the appropriate CAPC selection for the resulting packet. This preliminary action ensures that QoS differentiation is maintained from the outset, preventing loss of priority information before transmission begins.
3Speed
If the contention window is shortened for high CAPC priority, then the channel access speed increases, but the resource waste increases for low-priority data
Solution Approach 1:
The patent changes the CAPC parameter dynamically based on the data composition in the multiplexed packet. When high-priority data units are present, the system selects a higher CAPC priority (lower numerical value) which corresponds to a shorter contention window, thereby increasing channel access speed for urgent data. When only low-priority data is present, the system selects a lower CAPC priority (higher numerical value) with a longer contention window, reducing resource waste and energy consumption for non-urgent transmissions.
Data Source
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AI summary
Example embodiments of the present disclosure relate to devices, methods, apparatuses and computer readable storage medium for selection of a channel access priority. In example embodiments, a subset of data units from a set of data units is selected for multiplexing into a data packet. The selecting is at least in part based on a channel access priority associated with each of the subset of data unit. The subset of data units is multiplexed into the data packet, and then the data packet is transmitted.