HARQ Process ID Mapping for Semi-Persistent Scheduling Ambiguity
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Solution Overview
Problem
In wireless telecommunications, there is an ambiguity in associating HARQ process IDs with initial and retransmissions in semi-persistent scheduling, leading to confusion about which retransmissions correspond to which initial transmissions, especially when multiple initial transmissions share the same HARQ process ID.
Innovation Solution
Reserving HARQ process IDs for both initial and retransmissions and using a mapping rule based on system frame number, subframe, and period to uniquely assign IDs, ensuring that retransmissions are correctly linked to their corresponding initial transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If HARQ process IDs are reused for multiple initial transmissions in semi-persistent scheduling, then resource utilization is improved, but ambiguity arises in associating retransmissions with initial transmissions
Solution Approach 1:
The patent segments the HARQ process ID space by introducing a separate identifier field in the downlink control information that specifically identifies which initial transmission a retransmission corresponds to. This segmentation allows multiple initial transmissions to share HARQ process IDs while maintaining unique association through the additional identifier field.
Solution Approach 2:
The patent introduces an intermediary identifier field in the downlink control information that acts as a mediator between the reused HARQ process ID and the specific initial transmission. This intermediary carries the necessary association information without preventing HARQ process ID reuse, thus resolving the ambiguity while maintaining resource efficiency.
2Measurement precision
If HARQ process IDs are reserved for both initial and retransmissions, then association accuracy is improved, but the number of available HARQ process IDs is reduced
Solution Approach 1:
The patent segments the identification function into two parts: the HARQ process ID for process management and a separate identifier field in the downlink control information for precise association. This segmentation allows accurate retransmission tracking without requiring additional reserved HARQ process IDs, thus avoiding increased complexity.
Solution Approach 2:
The patent adds another dimension to the identification system by incorporating an identifier field within the downlink control information structure. This dimensional addition provides precise association capability without consuming additional HARQ process IDs, maintaining the existing pool size while improving association accuracy.
3Reliability
If mapping rules based on system frame number and subframe are used, then retransmission association is improved, but signaling overhead increases
Solution Approach 1:
The patent makes the downlink control information structure multi-functional by having it carry both the traditional scheduling information and the new identifier field for retransmission association. This universal approach consolidates multiple functions into a single signaling mechanism, avoiding additional overhead from separate mapping rule transmissions.
Solution Approach 2:
The patent performs the association identification in advance by including the identifier field in the downlink control information at the time of retransmission scheduling. This preliminary action eliminates the need for subsequent processing or additional signaling to determine associations, thereby reducing overall signaling overhead while improving reliability.
Data Source
AI summary
A system and method are provided for determining a minimum number of reserved hybrid automatic repeat request (HARQ) process identifiers (IDs). The method includes, determining a minimum number of reserved HARQ Process IDs based upon a maximum transmission time and a period of a semi-persistent resource allocation.