Spreading Code Sequences for Reference Signals in IoT
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Solution Overview
Problem
Current wireless communication systems face inefficiencies in resource allocation and collision management, particularly in IoT scenarios with massive connections, due to limited reference signal pools and high collision probabilities, which hinder resource efficiency and system stability.
Innovation Solution
The generation and application of non-orthogonal spreading codes to expand the reference signal pool, allowing for a larger set of reference signals that can carry control information without additional signaling overhead, thereby reducing collision probabilities and enhancing resource efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional reference signal pools are used in grant-free transmissions, then the system structure remains simple, but collision probability increases and resource efficiency decreases
Solution Approach 1:
The reference signal pool is segmented into multiple groups, where each group contains reference signals with different spreading codes. This segmentation allows the system to expand the effective reference signal pool size without requiring a complete redesign, thereby reducing collision probability while maintaining manageable system complexity through modular organization
Solution Approach 2:
The patent introduces spreading codes as an additional dimension to differentiate reference signals. Instead of merely increasing the number of reference signals in the time-frequency domain, the invention adds a code domain dimension, enabling multiple UEs to share the same time-frequency resources with different spreading codes, thus reducing collisions while efficiently utilizing existing resources
2Productivity
If the reference signal pool is expanded to reduce collisions, then resource efficiency improves, but control channel resources increase
Solution Approach 1:
Spreading codes serve multiple functions simultaneously: they differentiate reference signals from different UEs, enable channel estimation, and carry control information. This multi-functionality allows the system to expand the effective reference signal pool and improve resource efficiency without requiring additional dedicated control channel resources, as the spreading codes themselves fulfill multiple roles
Solution Approach 2:
The patent changes the parameter of spreading code assignment dynamically. Different spreading codes are assigned to different UEs or different transmission occasions, allowing the system to adaptively expand the reference signal pool capacity. This parameter change approach enables improved resource efficiency while maintaining the same physical control channel resource allocation
3Adaptability or versatility
If spreading codes are applied to reference signals, then the reference signal pool capacity increases, but the complexity of code generation and management increases
Solution Approach 1:
The patent extracts the code generation function into a separate, standardized process. Pre-defined spreading code sequences are extracted from mathematical sequences (such as Zadoff-Chu sequences or Gold sequences), and the base station extracts and assigns specific codes to UEs based on simple indexing rules. This extraction simplifies the overall system by separating code generation from resource allocation logic
Solution Approach 2:
Spreading codes are preliminarily configured and assigned to UEs before actual grant-free transmissions occur. The base station pre-assigns spreading code indices to UEs, and these assignments are stored and reused for multiple transmission occasions. This preliminary action eliminates the need for real-time code generation and assignment during transmissions, reducing management complexity while maintaining high reference signal pool capacity
Data Source
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AI summary
Methods, systems, and devices related to applying a spreading code to reference signals are described. In one exemplary aspect, a method for wireless communication includes receiving a message indicating a set of control options available to the mobile device for data transmissions. The method includes selecting a spreading code sequence from a number of spreading code sequences, wherein the spreading code sequence corresponds to a control option in the set of control options, wherein the number of spreading code sequences is greater than a length of each of the spreading code sequence, and wherein the spreading code sequences are generated using a method when the length of each of the spreading code sequences is greater than or equal to a value. The method also includes generating a plurality of reference signal symbols using the spreading code sequence, and transmitting the plurality of reference signal symbols.