LAA User Equipment Flexible PUSCH Starting Positions
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Solution Overview
Problem
In Licensed-Assisted Access (LAA) wireless communication, the challenge is to increase the likelihood of sending a Physical Uplink Shared Channel (PUSCH) in a scheduled subframe after Listen Before Talk (LBT) fails, leading to increased scheduling overhead and delay.
Innovation Solution
The solution involves a user equipment (UE) for LAA that can transmit a PUSCH starting from one of multiple candidate starting positions within a scheduled subframe if LBT is successful, allowing for flexible starting positions within the subframe.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LBT is performed before PUSCH transmission in LAA, then channel access compliance is achieved, but transmission delay increases and scheduling efficiency decreases
Solution Approach 1:
The patent performs LBT in advance before the scheduled PUSCH transmission time, allowing the UE to know early whether the channel will be available. This preliminary channel assessment enables proactive scheduling decisions and reduces uncertainty about transmission timing.
Solution Approach 2:
The patent introduces flexible PUSCH starting positions within a subframe, allowing the transmission start time to be dynamically adjusted based on LBT results. Instead of a fixed starting position, the system can select from multiple candidate positions to optimize both channel access compliance and transmission efficiency.
2Device complexity
If fixed PUSCH starting position is used in scheduled subframe, then scheduling simplicity is maintained, but transmission flexibility and success rate decrease
Solution Approach 1:
The patent divides the subframe into multiple candidate starting positions for PUSCH transmission. Instead of a single fixed position, the subframe is segmented into several possible start points, allowing the system to select the most appropriate position based on channel conditions and LBT results.
Solution Approach 2:
The patent changes the starting position parameter of PUSCH from a fixed value to a set of candidate values. This parameter flexibility allows the system to adapt the transmission timing to channel availability while maintaining structured scheduling through predefined candidate positions.
3Productivity
If multiple candidate starting positions are provided for PUSCH, then transmission flexibility and success rate increase, but scheduling complexity increases
Solution Approach 1:
The candidate starting positions are predefined and configured in advance through RRC signaling or system information. This preliminary configuration reduces real-time scheduling complexity by establishing a finite set of valid start positions before transmission occurs.
Solution Approach 2:
The patent introduces an intermediary layer of candidate starting positions that mediates between the fixed scheduling structure and the flexible channel access requirements. This intermediary set of positions provides a structured compromise that balances simplicity and flexibility.
Data Source
AI summary
Provided are a user equipment and a wireless communication method for LAA. The user equipment comprises: a receiver operative to receive a UL grant which schedules a subframe for UL transmission; a first circuit operative to perform LBT; a transmitter operative to transmit a PUSCH in the scheduled subframe starting from one available starting position of multiple candidate starting positions in the scheduled subframe if the LBT is successful. According to present disclosure, it is possible to increase the possibility that PUSCH could be sent in the scheduled subframe after LBT.