Grant-Free Uplink Data Transmission Using Code Element Groups
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Solution Overview
Problem
In LTE systems, the existing uplink scheduling request mechanism leads to heavy signaling overheads, and grant-free transmission methods face decoding reliability issues when multiple terminals use the same code domain resource in a contention transmission unit.
Innovation Solution
A data transmission method that determines a contention transmission unit (CTU) including time, frequency, and code domain resources, encodes uplink data using multiple code element groups, and sends these encoded data groups with control words to instruct combined decoding, ensuring correct reception even if different terminals use the same code domain resource.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple terminals use the same code domain resource in a contention transmission unit for grant-free transmission, then resource utilization is improved, but decoding reliability deteriorates because the receive end cannot decode the data when different terminals select the same code domain resource
Solution Approach 1:
The code domain resource is segmented into multiple code element groups, where each group contains multiple code elements. This segmentation allows the system to organize code resources hierarchically, enabling multiple terminals to use the same CTU while selecting different code element groups or combinations, thereby reducing code domain collisions and improving decoding reliability while maintaining resource utilization.
Solution Approach 2:
The patent introduces a new dimension for code resource organization by creating code element groups with different group indices. Terminals can be configured with mappings between code element groups and code domains, allowing them to select code elements from different groups even when using the same CTU. This dimensional expansion resolves the contradiction by providing additional differentiation beyond the traditional single code domain selection.
2Reliability
If traditional uplink scheduling request mechanism is used in LTE system, then resource allocation is ensured, but signaling overhead increases heavily
Solution Approach 1:
The patent extracts the resource allocation function from the traditional scheduling request mechanism by implementing grant-free transmission. Terminals are pre-configured with multiple CTUs and their corresponding code element group mappings, allowing them to directly select and use resources without requesting allocation. This extraction eliminates the scheduling request signaling while maintaining reliable resource allocation through the pre-configured code element group structure.
Solution Approach 2:
The system performs preliminary configuration of code element groups and their mappings to code domains before actual data transmission. Terminals receive configuration information containing multiple CTUs and their associated code element group mappings in advance, enabling them to autonomously select resources without real-time scheduling requests. This preliminary action reduces signaling overhead while ensuring reliable resource allocation is already in place.
Data Source
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AI summary
Embodiments of the present invention provide a data transmission method and apparatus. The method includes: determining a contention transmission unit CTU to be used by to-be-sent uplink data, where the CTU is a transmission resource including at least a time domain resource, a frequency domain resource, and a code domain resource; encoding the to-be-sent uplink data by using N different code element groups in the code domain resource corresponding to the determined CTU, to obtain N groups of encoded data, where N is a positive integer greater than or equal to 2; and sending the N groups of encoded data by using the time domain and frequency domain resources that are corresponding to the determined CTU. According to the embodiments of the present invention, data reception reliability at a receive end can be improved.