Shared HARQ Entity for Multi-Carrier Retransmission
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Solution Overview
Problem
Existing technologies face challenges in ensuring reliable quality of service in band-limited carriers, particularly in unlicensed spectrum, due to issues like latency, high UE loading, correlated fading, and LBT failures, which affect HARQ retransmissions and ACK/NACK feedback in unlicensed component carriers.
Innovation Solution
Implementing systems and methods for shared and mapped HARQ processes across multiple carriers, using semi-static and dynamic signaling to indicate data duplication, and employing auxiliary HARQ processes for retransmissions when primary channels are blocked.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If HARQ retransmissions are performed on the same carrier, then reliability is improved, but latency increases due to time-domain repetition
Solution Approach 1:
The patent transitions HARQ retransmissions from the time domain to the frequency domain by enabling retransmissions on different component carriers. Instead of repeating transmissions sequentially in time on the same carrier, the system schedules retransmissions across multiple frequency carriers, thereby reducing latency while maintaining reliability through frequency diversity.
2Reliability
If multiple carriers are used for data duplication, then reliability is improved, but device complexity increases due to separate MAC entities
Solution Approach 1:
The patent implements a shared HARQ entity that serves multiple component carriers universally. Instead of dedicating separate MAC entities and HARQ processes to each carrier, a single HARQ entity manages retransmissions across multiple carriers, reducing complexity while maintaining the reliability benefits of multi-carrier diversity.
3Adaptability or versatility
If LBT procedure is performed on unlicensed carriers, then spectrum sharing is enabled, but transmission reliability deteriorates due to LBT failures
Solution Approach 1:
The patent introduces a licensed carrier as an intermediary for HARQ retransmissions when unlicensed carriers experience LBT failures. The licensed carrier serves as a reliable backup path, ensuring that critical retransmissions can occur without being blocked by LBT procedures, thereby maintaining reliability while preserving unlicensed spectrum sharing capabilities.
4Productivity
If carrier aggregation is used to enhance data rate, then productivity is improved, but HARQ process management becomes more complex
Solution Approach 1:
The patent merges the HARQ management functions across multiple component carriers into a single shared HARQ entity. This consolidation simplifies the management of HARQ processes while preserving the high data rates achieved through carrier aggregation, as the unified entity can efficiently coordinate retransmissions across all aggregated carriers.
Data Source
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AI summary
A method includes receiving a first assignment for a first transmission with a first hybrid automatic repeat request (HARQ) process identifier (process ID) in a first network resource, receiving a second assignment for a second transmission with a second HARQ process ID in a second network resource, wherein the first network resource and the second network resource differ in a domain other than a time domain, detecting an indication indicating that the first HARQ process ID and the second HARQ process ID map to a same transmission block (TB), and communicating with an access node, a transmission associated with at least one of the first HARQ process ID or the second HARQ process ID.