Autonomous Uplink Transmission HARQ Collision Avoidance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In wireless communication systems, especially in unlicensed bands, there is a need to avoid collisions between dynamic and autonomous uplink transmission processes, particularly when hybrid automatic repeat request (HARQ) processes are involved, as existing methods struggle to manage these processes effectively without interference.
Innovation Solution
A method and device for autonomous transmission in an unlicensed band, which includes receiving a semi-persistent scheduling (SPS) configuration and downlink control information with an uplink grant containing a unique HARQ identifier, and performing uplink transmission only after confirming the wireless medium is idle through listen before talk (LBT, ensuring distinct HARQ identifiers are used for different transmission processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If dynamic UL transmission and autonomous UL transmission co-exist in unlicensed band, then resource utilization is improved, but HARQ process collision occurs
Solution Approach 1:
The patent segments the HARQ process space by dedicating specific HARQ process identifiers to either dynamic UL transmission or autonomous UL transmission. This segmentation prevents overlap and collision between the two transmission types while allowing both to coexist in the unlicensed band, thus maintaining high resource utilization without HARQ process conflicts
Solution Approach 2:
The patent introduces a scheduling mechanism that acts as an intermediary between dynamic and autonomous UL transmissions. The base station schedules autonomous transmissions in a coordinated manner with dynamic transmissions, using intermediate control signals and timing adjustments to prevent HARQ process collision while maximizing resource utilization
2Reliability
If LBT is performed in SPS window for autonomous transmission, then channel access reliability is improved, but transmission delay increases
Solution Approach 1:
The patent performs LBT in advance within the SPS window before actual data transmission. By conducting the listen-before-talk procedure preliminarily and caching the channel access result, the system ensures reliable channel access while minimizing the delay impact on subsequent transmissions
Solution Approach 2:
The patent utilizes the periodic nature of SPS windows to perform LBT at regular intervals. This periodic action allows the system to maintain reliable channel access through repeated LBT attempts while optimizing the timing to minimize overall transmission delay across multiple SPS periods
Data Source
AI summary
A method and an apparatus for autonomous transmission in an unlicensed band are provided. The method and apparatus comprising: a wireless device receiving a semi-persistent scheduling (SPS) configuration for first uplink transmission, wherein the SPS configuration includes information regarding an SPS window indicating a time section in which the first uplink transmission is allowed; the wireless device receiving on a DL channel downlink control information (DCI) having an uplink grant that instructs second uplink transmission, wherein the uplink grant includes a second hybrid automatic repeat request process identifier (HARQid) for the second uplink transmission; and the wireless device performing the first uplink transmission in the SPS window when it is confirmed that a wireless medium is in an idle state by performing a listen before talk (LBT) in the SPS window, wherein a first HARQid for the first uplink transmission is not the same as the second HARQid.