Hierarchical Modulation for Mixed URLLC and eMBB Services
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Solution Overview
Problem
Current wireless communication systems face challenges in efficiently managing mixed services such as Enhanced Mobile Broadband (eMBB) and Ultra Reliable and Low Latency Communications (URLLC) due to differences in priority and quality of service requirements, particularly in adapting modulation schemes based on network conditions.
Innovation Solution
The implementation of hierarchical modulation techniques, where eMBB and URLLC bit-streams are transmitted using multiple or single modulation layers depending on network conditions, with eMBB mapped to an enhancement layer and URLLC to a base layer, allowing dynamic adjustment of bit allocation based on channel state information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple hierarchical modulation layers are used to transmit both eMBB and URLLC bit-streams, then transmission reliability for URLLC is improved, but device complexity increases
Solution Approach 1:
The patent segments the transmission into multiple hierarchical modulation layers, with the base layer carrying URLLC data and the enhancement layer carrying eMBB data. This segmentation allows the receiver to first decode the more robust base layer (improving URLLC reliability) and then optionally decode the enhancement layer for additional eMBB throughput, thereby improving reliability without proportionally increasing overall system complexity.
Solution Approach 2:
The patent applies different modulation and coding schemes to different layers: the base layer uses more robust modulation (e.g., QPSK) and higher coding rates suitable for reliable URLLC transmission, while the enhancement layer uses higher-order modulation (e.g., 64-QAM) optimized for eMBB throughput. This local optimization of quality parameters allows each layer to be tuned for its specific service requirements.
2Loss of time
If eMBB data is punctured to allow URLLC data transmission, then latency for URLLC is reduced, but data rate for eMBB deteriorates
Solution Approach 1:
The patent implements dynamic resource allocation where the network can dynamically switch between transmission modes: hierarchical modulation when both services need to be served, or puncturing when URLLC latency requirements are critical. The system adapts the transmission strategy based on real-time channel conditions, URLLC arrival patterns, and eMBB buffer states, allowing flexible trade-off management between latency and throughput.
Solution Approach 2:
The patent extracts URLLC data from the shared resource allocation and transmits it separately with higher priority. By taking out the URLLC transmission requirements and handling them through puncturing or separate resource allocation, the system ensures low-latency delivery while minimizing impact on eMBB service through efficient resource management and potential retransmission of punctured eMBB data.
3Device complexity
If a single modulation layer is used for transmission, then device complexity is reduced, but transmission reliability for URLLC deteriorates
Solution Approach 1:
The patent merges URLLC and eMBB transmissions into a unified hierarchical modulation framework where both services share the same time-frequency resources. By combining the transmissions in a structured manner with the base layer (URLLC) and enhancement layer (eMBB), the system achieves reliable URLLC delivery without requiring separate dedicated resources, thereby avoiding the complexity of completely separate transmission systems while maintaining high reliability.
Data Source
AI summary
Systems, procedures, and instrumentalities are disclosed providing mixed data services such as mixed URLLC and eMBB services. In one example implementation, hierarchical modulation is dynamically configured and/or applied to provide the mixed services. The dynamic configuration and application of hierarchical modulation may be based on the respective priorities of the services and a condition of the concerned wireless network. The provision of the mixed services may utilize polar coding techniques. Control information may be mixed with data associated with the services.