Scrambling Sequence Initialization for Interference Diversity in Wireless Systems
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Solution Overview
Problem
Low latency and high reliability wireless communication systems face challenges in achieving interference diversity, particularly in scenarios where transmission opportunities have varying interference patterns, leading to decoding failures in initial transmissions.
Innovation Solution
The implementation of different scrambling sequences for data, control, and demodulation reference signals in various transmission opportunities, initialized based on transmission time interval (TTI) numerology, such as shortened TTI or mini-slot indices, to ensure distinct interference patterns for each transmission opportunity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the same scrambling sequence is used across transmission opportunities, then device complexity is reduced, but reliability deteriorates due to identical interference patterns causing decoding failures
Solution Approach 1:
The patent applies dynamics by making the scrambling sequence variable rather than static. The scrambling sequence is dynamically changed based on transmission opportunity index, TTI numerology, and interference conditions, allowing the system to adapt to varying interference patterns across different transmission opportunities while maintaining manageable complexity through standardized selection criteria.
Solution Approach 2:
The patent changes the parameters of the scrambling sequence (such as initialization values, sequence length, or pattern) based on transmission opportunity characteristics and detected interference conditions. This parameter variation enables the system to achieve different interference diversity while using a controlled set of sequence configurations, balancing reliability improvement with device complexity.
2Reliability
If different scrambling sequences are applied in each transmission opportunity, then interference diversity is improved, but device complexity increases
Solution Approach 1:
The patent segments the scrambling sequence selection into distinct categories based on TTI numerology types (e.g., shortened TTI, mini-slot, normal TTI) and transmission opportunity phases (initial transmission vs. retransmission). This segmentation allows devices to select appropriate sequences from predefined sets rather than generating arbitrary sequences, reducing complexity while maintaining interference diversity.
Solution Approach 2:
The patent implements periodic changes in scrambling sequences based on transmission opportunity indexing and TTI boundaries. By systematically rotating through different sequence configurations in a periodic manner tied to the transmission schedule, the system achieves interference diversity without requiring complex real-time sequence generation, as the changes follow predictable periodic patterns.
3Reliability
If scrambling sequences are frequently changed to achieve interference diversity, then reliability improves, but processing overhead increases
Solution Approach 1:
The patent performs preliminary configuration of scrambling sequences during system setup or connection establishment phases. Devices pre-determine and store appropriate scrambling sequence sets for different TTI numerologies and transmission scenarios, so that during actual transmissions, they only need to select from pre-configured options rather than generating sequences in real-time, thereby reducing processing energy while maintaining reliability.
Data Source
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AI summary
Techniques are described for wireless communication. A method for wireless communication at a user equipment (UE) includes receiving an indication of a transmission time interval (TTI) configuration; determining a scrambling sequence initialization timing based at least in part on a TTI numerology associated with the TTI configuration; and communicating with the base station on a downlink or an uplink according to a scrambling sequence initialized based at least in part on the determined scrambling sequence initialization timing. The TTI configuration is one TTI configuration in a plurality of available TTI configurations for communicating with a base station.