Semi-Persistent Scheduling in TDD Subframes
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Solution Overview
Problem
In LTE systems, dynamic changes in TDD uplink and downlink proportion configurations cause flexible subframes to disrupt semi-persistent scheduling (SPS) transmissions, as subframes originally used for uplink or downlink may change, affecting normal SPS operation.
Innovation Solution
A method to determine a constant subframe set within a TDD frame where uplink and downlink attributes remain unchanged during dynamic configuration changes, allowing SPS transmission to occur only in subframes with consistent attributes, thereby isolating SPS from flexible subframe impacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If dynamic TDD uplink and downlink proportion configuration is implemented, then adaptability to traffic changes is improved, but SPS transmission reliability deteriorates due to flexible subframes
Solution Approach 1:
The patent segments the TDD subframes into two distinct sets: constant subframes (where uplink/downlink attributes remain unchanged during configuration changes) and flexible subframes (where attributes may change). This segmentation allows the system to maintain SPS transmission reliability in constant subframes while still enabling dynamic adaptation through flexible subframes, thus resolving the contradiction between adaptability and reliability.
Solution Approach 2:
The patent applies different characteristics to different subframe sets: constant subframes maintain fixed uplink/downlink attributes to ensure SPS reliability, while flexible subframes allow dynamic attribute changes to provide adaptability. This local differentiation of subframe qualities enables the system to simultaneously achieve both reliability in critical areas and adaptability in flexible areas.
2Adaptability or versatility
If flexible subframes are introduced for dynamic configuration, then system adaptability is improved, but SPS transmission stability deteriorates
Solution Approach 1:
The patent divides the TDD frame structure into constant subframes and flexible subframes. Constant subframes provide stable uplink/downlink attributes for SPS transmission, while flexible subframes enable dynamic configuration changes. This segmentation maintains SPS transmission stability in constant subframes while allowing system adaptability through flexible subframes.
Solution Approach 2:
The patent uses constant subframes as intermediaries that bridge the contradiction between adaptability and stability. These subframes maintain consistent attributes across different configurations, serving as stable anchors for SPS transmission while the system as a whole can adapt through flexible subframes.
3Adaptability or versatility
If subframe directions can change dynamically, then resource allocation flexibility is improved, but SPS operation complexity increases
Solution Approach 1:
The patent segments subframes into constant and flexible categories, allowing the UE to identify which subframes have fixed attributes and which may change. This segmentation simplifies SPS operation by enabling the UE to focus on constant subframes for reliable transmission while being aware of flexible subframes for potential resource allocation adjustments.
Solution Approach 2:
The patent enables the UE to autonomously determine constant subframe sets based on configured TDD uplink and downlink proportion configurations. The UE can self-identify which subframes are suitable for SPS transmission without requiring complex external control, thus reducing operational complexity while maintaining flexibility.
Data Source
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AI summary
The present invention relates to the field of communications technologies, and provides a semi-persistent scheduling method and user equipment. The semi-persistent scheduling method includes: determining a constant sub frame set in a TDD frame, where an uplink and downlink attribute of each subframe in the constant subframe set remains unchanged when an uplink and downlink proportion configuration of the TDD frame dynamically changes; and performing SPS transmission in a subframe, in the constant subframe set, whose uplink and downlink attribute is the same as a transmission direction of the SPS transmission. In this way, SPS transmission can be normally performed without being affected by a flexible subframe in a case in which a TDD uplink and downlink proportion is dynamically configured for a UE.