Truncated MAC CE Reporting Under Constrained Uplink Grants
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Solution Overview
Problem
The challenge in wireless communication systems is the efficient utilization of limited radio resources by base stations to handle increased data and control information, particularly in scenarios with high latency requirements, such as those involving user equipment (UEs) that require timely transmission of Medium Access Control (MAC) control elements.
Innovation Solution
A method and apparatus for a user equipment (UE) to generate and transmit a truncated MAC Protocol Data Unit (PDU) that includes a truncated MAC CE report, containing information about unaccommodated MAC CEs, using a bitmap field and Logical Channel IDs, prioritized in logical channel prioritization, to efficiently utilize uplink grants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If the UE includes all triggered MAC CEs in the MAC PDU, then the network receives complete control information, but the uplink grant may be insufficient to accommodate all MAC CEs
Solution Approach 1:
The MAC CE report is segmented into multiple parts: included MAC CEs that fit within the uplink grant, and truncated MAC CEs that exceed the grant size. The segmentation is achieved by identifying which MAC CEs can be accommodated and which must be truncated, allowing the UE to transmit available information while indicating missing information through the truncated field.
Solution Approach 2:
A truncated field is introduced as an intermediary mechanism to convey information about MAC CEs that cannot be included in the MAC PDU. This truncated field acts as a mediator between the limited uplink grant and the complete set of triggered MAC CEs, allowing the network to infer the presence of additional MAC CEs that were not transmitted.
2Productivity
If the UE transmits truncated MAC CE reports, then uplink resources are utilized efficiently, but latency may increase for critical MAC CEs like LBT failure and Beam Failure Recovery
Solution Approach 1:
The invention changes the parameter representation by introducing a truncated field with specific bit patterns that indicate the presence of truncated MAC CEs. This parameter change allows the network to quickly identify which MAC CEs were truncated and prioritize their transmission, reducing latency for critical information without sacrificing overall uplink resource utilization efficiency.
3Loss of energy
If the MAC PDU is optimized to fit within the uplink grant, then resource efficiency improves, but critical MAC CEs may be excluded or partially included
Solution Approach 1:
The UE performs preliminary action by including priority indicators and truncated field information in the MAC PDU before actual transmission. This allows the network to pre-identify which MAC CEs are critical and may have been truncated, enabling the network to prioritize subsequent transmissions and ensure reliable delivery of critical information while maintaining efficient use of the current uplink grant.
Data Source
AI summary
A method for transmitting a truncated Medium Access Control (MAC) Control Element (CE) report by a user equipment (UE) in a wireless communication system. The method includes triggering transmissions of one or more MAC CEs; receiving an uplink grant from a network; based on the uplink grant not accommodating the one or more MAC CEs, generating a MAC Protocol Data Unit (PDU) including a truncated MAC CE report; transmitting the MAC PDU to the network, wherein the truncated MAC CE report includes information related to at least one MAC CE which is triggered but not included or partially included in the MAC PDU among the one or more MAC CEs.