s-PUCCH Collision Handling in Shortened TTI Wireless Systems
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Solution Overview
Problem
Current wireless communication systems face limitations in achieving low latency and efficient communication due to constraints in physical channel designs for shortened Transmission Time Interval (TTI) and Round Trip Time (RTT), which are crucial for applications like the Tactile Internet and real-time robotics.
Innovation Solution
The implementation of specific physical layer procedures and channel designs for shortened TTI and RTT, including hybrid automatic repeat request acknowledgment processes, soft buffer handling, power control, and collision handling of uplink control information channels, allows for efficient multiplexing of legacy and shortened TTI channels, enhancing communication flexibility and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If legacy PUCCH structure is reused for s-PUCCH in 0.5ms s-TTI, then multiplexing with legacy PUCCH is possible, but communication flexibility is limited for shorter TTIs
Solution Approach 1:
The patent implements dynamic TTI length configuration where the system can switch between legacy TTI and shortened TTI modes. The PUCCH structure adapts dynamically based on the configured TTI length, allowing flexible communication patterns while maintaining a unified design framework that avoids separate legacy and new channel designs.
Solution Approach 2:
The patent creates a universal PUCCH design that serves both legacy and shortened TTI requirements. By defining a configurable PUCCH structure that can adapt to different TTI lengths through parameters like symbol allocation and resource mapping, the system achieves multi-functionality without requiring separate dedicated structures for each TTI type.
2Loss of time
If new s-PUCCH design is implemented for 3(4) SC-FDMA symbol s-TTI, then low latency is achieved, but multiplexing with legacy PUCCH becomes impossible
Solution Approach 1:
The patent segments the PUCCH design into configurable functional blocks that can be independently adjusted for different TTI lengths. For shortened TTIs, the PUCCH structure is segmented to occupy only the necessary 3-4 SC-FDMA symbols, while legacy PUCCH can operate in remaining resources or different time slots, enabling both short latency operation and multiplexing capability.
Solution Approach 2:
The patent employs parameter-based configuration where key PUCCH parameters (number of symbols, resource block allocation, modulation scheme) are dynamically adjusted based on the active TTI length. This allows the same physical channel to support both shortened TTI for low latency and legacy TTI for multiplexing, simply by changing operational parameters rather than structural design.
3Reliability
If collision handling drops PUCCH during s-PUCCH transmission, then s-PUCCH reliability is improved, but control information transmission may be lost
Solution Approach 1:
The patent implements preliminary collision detection and handling mechanisms where the system proactively identifies potential PUCCH-s-PUCCH collisions before transmission. Configuration parameters are pre-set to prioritize s-PUCCH resources, and alternative transmission paths are prepared in advance, ensuring that control information is preserved through pre-planned fallback options rather than reactive dropping.
Solution Approach 2:
The patent introduces an intermediary collision resolution layer that mediates between PUCCH and s-PUCCH transmissions. This intermediary mechanism uses configured priority rules and resource coordination to resolve collisions, potentially by scheduling adjustments or resource reallocation, rather than simple dropping, thereby preserving control information while maintaining s-PUCCH reliability.
Data Source
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AI summary
A user equipment (UE) is described that includes a higher-layer processor configured to configure a shortened transmission timing interval (TTI) for a serving cell. The UE also includes a physical uplink channel transmitter configured to transmit a physical uplink control channel (PUCCH) on the serving cell. The UE further includes a shortened physical uplink channel transmitter configured to transmit a shortened physical uplink control channel (SPUCCH) on the serving cell. In a case that a transmission instance of the SPUCCH collides with an uplink subframe where the PUCCH is to be transmitted, the PUCCH is dropped, and the SPUCCH is transmitted.