LAA PUSCH Format Signaling for Contention Access
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Solution Overview
Problem
Current wireless communication systems face limitations in communication flexibility and efficiency, particularly in Licensed-Assisted Access (LAA) uplink transmissions, where the hidden node problem and restricted LBT methods hinder efficient channel access and simultaneous transmissions.
Innovation Solution
The implementation of dynamic signaling for LBT methods and PUSCH formats in LAA systems, allowing for flexible channel access and contention resolution based on the availability of the last symbol of the previous subframe, enables efficient channel access and supports simultaneous UL transmissions from multiple UEs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Listen Before Talk (LBT) channel access is required before PUSCH transmission, then channel access reliability is improved, but transmission delay increases and communication efficiency deteriorates
Solution Approach 1:
The patent implements dynamic PUSCH format selection based on LBT success status. When LBT succeeds, a first PUSCH format is used; when LBT fails, a second PUSCH format is used. This dynamic adaptation allows the system to optimize between reliability (when LBT succeeds) and time efficiency (when LBT fails), resolving the contradiction by making the system flexible rather than fixed.
Solution Approach 2:
The patent changes the PUSCH format parameter based on LBT outcome. The network device configures multiple PUSCH formats with different characteristics, and the UE selects the appropriate format based on whether LBT succeeded or failed. This parameter change allows the system to adapt transmission characteristics to current channel conditions, balancing reliability and delay requirements.
2Adaptability or versatility
If dynamic signaling for PUSCH format is implemented, then communication flexibility is improved, but system complexity increases
Solution Approach 1:
The network device performs preliminary configuration by pre-defining multiple PUSCH formats and their characteristics before actual transmission occurs. The UE stores these pre-configured formats and can quickly switch between them based on LBT outcomes, avoiding the need for complex real-time format negotiation and reducing signaling overhead during actual transmission.
Solution Approach 2:
The system implements feedback mechanisms where the network device receives information about LBT success/failure from the UE and can adjust subsequent PUSCH format assignments accordingly. This feedback loop enables adaptive optimization of communication flexibility while maintaining manageable system complexity through structured feedback channels.
3Productivity
If multiple UEs perform simultaneous uplink transmissions, then communication efficiency is improved, but interference increases and channel access becomes more difficult
Solution Approach 1:
The patent segments the uplink transmission resource by introducing different PUSCH formats for different LBT outcomes. This segmentation allows the system to handle simultaneous transmissions from multiple UEs more effectively by assigning appropriate formats based on individual LBT results, thereby managing interference while maintaining overall communication efficiency.
Data Source
AI summary
A user equipment (UE) for transmitting signals in a Licensed-Assisted Access (LAA) serving cell is described. The UE includes a processor and memory in electronic communication with the processor. The UE receives an uplink (UL) grant for one or more UL LAA subframes from one or more downlink control information (DCI). The UE also determines a UL LAA physical uplink shared channel (PUSCH) format or structure for a UL LAA subframe. The UE further determines whether listen before talk (LBT) is needed for a scheduled LAA PUSCH. If needed, the UE determines a UL contention access region based on the UL grant for a UL LAA subframe. The UE also determines a UL contention access method in the contention access region. The UE further performs UL contention access in the UL contention access region. The UE additionally transmits the LAA PUSCH if channel access succeeds.