Uplink Grant Handling for Different PUSCH Starting Positions
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In LTE systems, user equipment (UE) faces challenges when receiving uplink grants on Licensed Assisted Access (LAA) secondary cells indicating different Physical Uplink Shared Channel (PUSCH) starting positions within the same subframe, leading to issues with listen-before-talk (LBT) operations during transmission mode.
Innovation Solution
The UE aligns the PUSCH starting position to the earliest or latest indicated position and may skip processing later grants while in transmission mode, and continues LBT for later grants if initial attempts fail, relaxing the simultaneous transmission and reception constraints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the UE processes multiple uplink grants indicating different PUSCH starting positions in the same subframe, then the uplink transmission scheduling flexibility is improved, but the device complexity and operational difficulty increase due to LBT constraints
Solution Approach 1:
The patent segments the handling of multiple uplink grants by introducing a priority mechanism. The UE identifies and processes grants with different priorities (e.g., based on DCI format, RNTI type, or grant index), allowing systematic management of multiple grants with different PUSCH starting positions rather than treating them as a single complex set of constraints
Solution Approach 2:
The patent changes the operational parameters by allowing the UE to adjust its transmission behavior based on LBT outcomes. When LBT fails for earlier PUSCH starting positions, the UE can proceed with later positions, effectively changing the time-domain parameters of transmission based on channel conditions and LBT results
2Reliability
If the UE performs LBT operations for multiple PUSCH starting positions, then the reliability of uplink transmission is improved, but the loss of time increases due to repeated LBT attempts
Solution Approach 1:
The patent applies preliminary action by having the UE perform LBT operations in advance for multiple PUSCH starting positions before actual transmission. The UE prepares by attempting LBT for earlier positions first, and if successful, can proceed directly to transmission without waiting for later positions, thereby reducing actual transmission delay while maintaining reliability
Solution Approach 2:
The patent implements skipping by allowing the UE to rush through the LBT process for subsequent PUSCH starting positions if earlier positions are successfully cleared. Once LBT succeeds for an earlier position, the UE can skip redundant LBT attempts for later positions and proceed directly to transmission, reducing time loss while maintaining transmission reliability
3Adaptability or versatility
If the UE is constrained to simultaneous transmission and reception operations, then the device capability is improved, but the ease of operation deteriorates due to complex coordination requirements
Solution Approach 1:
The patent extracts the complexity of simultaneous transmission and reception coordination by separating these operations in time. The UE performs LBT and transmission operations sequentially for different PUSCH starting positions rather than attempting simultaneous operations, thereby removing the complex coordination requirements while maintaining the ability to handle multiple grants
Data Source
AI summary
Methods, systems, and computer-readable storage media are provided for handling uplink grants indicating different physical uplink shared channel (PUSCH) starting positions in a same subframe of enhanced Licensed Assisted Access (eLAA) systems. In embodiments, a user equipment (UE) may receive Downlink Control Information (DCI). The DCI may indicate at least two uplink grants for one or more LAA secondary cell. Each of the at least two uplink grants may indicate different starting positions for PUSCH transmissions within a same subframe. The UE may align the different starting positions such that the UE is to transmit uplink transmissions according to the at least two uplink grants while the UE is in a transmission mode. Other embodiments may be described and/or claimed.