Randomizing Short TTI Uplink Transmissions via Hopping Patterns
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Solution Overview
Problem
Current communication systems face challenges in achieving highly reliable and low latency communication, particularly in Ultra-Reliable Low Latency Communication (URLLC) scenarios, where randomization of short transmission time interval transmissions is needed to mitigate collisions and improve resource utilization.
Innovation Solution
The method involves dynamic indication of demodulation reference signal (DMRS) positions and pre-allocation of resources for user equipment (UE) in short transmission time intervals (sTTIs), along with hopping patterns in the frequency and cyclic shift domains to randomize UL transmissions, allowing for DMRS sharing and reducing collisions among UEs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If randomization of short TTI transmissions is implemented to mitigate collisions, then reliability of HRLLC is improved, but device complexity increases due to additional hopping patterns and DMRS position management
Solution Approach 1:
The patent implements dynamic DMRS position indication where the DMRS position varies across different short TTIs based on hopping patterns. This dynamic adjustment randomizes UL transmissions and mitigates collisions while maintaining reliability, resolving the contradiction between improved reliability and increased complexity by making the system adaptive rather than static
Solution Approach 2:
The patent changes multiple parameters including DMRS position, cyclic shift values, and frequency domain resources across different short TTIs. By systematically varying these parameters according to configured hopping patterns, the system achieves collision randomization and improved HRLLC reliability without requiring fundamentally new system architecture
2Productivity
If DMRS sharing is enabled to support more UEs, then productivity increases, but measurement precision deteriorates due to potential interference between shared DMRS
Solution Approach 1:
The patent applies different cyclic shift values to different UEs sharing the same DMRS resources. This local differentiation in the cyclic shift domain allows multiple UEs to share DMRS in the same time-frequency resources while maintaining orthogonality and measurement precision, thus enabling increased productivity without sacrificing measurement quality
Solution Approach 2:
The patent moves the differentiation of shared DMRS from the time-frequency domain to the cyclic shift domain. By utilizing the cyclic shift dimension as an additional degree of freedom, the system enables multiple UEs to share DMRS resources while maintaining distinguishability and measurement precision
3Reliability
If hopping patterns are applied in frequency and cyclic shift domains to randomize UL transmissions, then collisions are reduced, but ease of operation decreases due to more complex resource management
Solution Approach 1:
The patent configures hopping patterns and DMRS positions in advance through RRC signaling before actual UL transmissions occur. This preliminary configuration allows the UE to automatically apply the correct hopping patterns without real-time decision-making, reducing collision through pre-planned randomization while keeping operation simple through automated execution
Data Source
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AI summary
Various communication systems may benefit from appropriate collision avoidance mechanisms. For example, highly reliable and low latency communication systems may benefit from the randomization of short transmission time interval transmissions. A method can include receiving a configuration of uplink resources for autonomous transmissions, wherein the configuration comprises an indication of which of a plurality of hopping patterns to apply. The method can also include transmitting the autonomous transmissions based on the configured uplink resources including the indicated hopping pattern.