Buffer Indication MAC CE for 5G Uplink Sidelink BSR Delay
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Solution Overview
Problem
In 5G mobile communication technology, when a user equipment (UE) has both uplink and sidelink buffer state reports (BSRs) to send simultaneously, the existing methods fail to efficiently transmit both reports, leading to increased delays in uplink and sidelink services due to the inability to carry both BSRs in the same uplink MAC PDU.
Innovation Solution
The proposed solution involves adding an indication MAC control element (CE) to the uplink MAC protocol data unit (PDU) when both BSRs cannot be carried simultaneously. This indication CE alerts the base station that the UE has pending BSRs, allowing the base station to schedule appropriate resources for their transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If the uplink MAC PDU is used to carry both BSR MAC CEs simultaneously, then the reporting completeness is improved, but the transmission delay increases due to resource scheduling inefficiency
Solution Approach 1:
The patent applies preliminary action by using a short BSR MAC CE to indicate the presence of a long BSR MAC CE in advance. This allows the base station to pre-schedule resources for the long BSR transmission, avoiding delays while ensuring complete BSR reporting. The short BSR acts as a preliminary notification that triggers subsequent resource allocation for the full BSR content.
2Loss of information
If the MAC PDU size is increased to accommodate both BSR MAC CEs, then the reporting capability is improved, but the resource utilization efficiency deteriorates
Solution Approach 1:
The patent segments the BSR information into two parts: a short BSR MAC CE that fits within the MAC PDU to trigger resource scheduling, and a long BSR MAC CE that is transmitted separately in a subsequently scheduled transmission. This segmentation allows the initial MAC PDU to remain compact while still enabling complete BSR reporting through coordinated multi-step transmission, thus maintaining high resource utilization efficiency.
3Device complexity
If a single BSR MAC CE is used to reduce overhead, then the transmission efficiency is improved, but the ability to report both uplink and sidelink buffer statuses deteriorates
Solution Approach 1:
The patent introduces a short BSR MAC CE as an intermediary element that mediates between the need for compact MAC PDU overhead and the requirement to report both uplink and sidelink buffer statuses. This short BSR acts as a trigger that conveys essential scheduling information, enabling the base station to allocate resources for transmitting the complete dual-BSR information in a subsequent transmission, thus maintaining low overhead while preserving full reporting capability.
Data Source
AI summary
The present disclosure provides buffer indication methods, resource transmission methods, user equipments, base stations and computer readable storage media. The buffer indication method includes: when a to-be-sent first and second BSR are present at the same time, determining that an uplink MAC PDU is incapable of carrying both a first and second BSR MAC CE at the same time, adding an indication MAC CE to the uplink MAC PDU and sending the MAC PDU with the MAC CE to a base station. The MAC CE indicates that a UE has a to-be-sent BSR; receiving information on an uplink resource sent by the base station to the UE based on the MAC CE; sending a to-be-sent BSR MAC CE to the base station based on the uplink resource; receiving information on a transmission resource of a corresponding type sent by the base station to the UE based on the to-be-sent BSR.