NDI Flag Derivation for Semi-Persistent Scheduling
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Solution Overview
Problem
In wireless communication systems, there is a lack of reliable methods to signal the new data indicator (NDI) flag for semi-persistently allocated transmission resources, especially in scenarios without explicit PDCCH signaling, which hinders efficient data interpretation and retransmission handling.
Innovation Solution
An apparatus and method that determine the value of the NDI flag using predefined values (e.g., zero for initial transmissions and one for retransmissions) and derive it based on semi-persistent scheduling, HARQ processes, and system frame numbers, allowing the flag to be toggled or fixed for different allocation scenarios, ensuring accurate data handling and resource management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If semi-persistent allocation of transmission resources is used to optimize control channel resources, then control channel resource utilization is improved, but the ability to reliably signal NDI flag is worsened
Solution Approach 1:
The patent introduces an intermediary mechanism where the NDI flag value is derived from existing signaling elements (PDCCH presence/absence, HARQ process number, system frame number) rather than being directly transmitted. This intermediary derivation process allows the NDI information to be conveyed indirectly through the semi-persistent scheduling framework without requiring additional explicit signaling, thus maintaining control channel resource efficiency while enabling reliable NDI indication.
Solution Approach 2:
The system enables the NDI flag to be self-determined by the receiving equipment through local derivation based on pre-agreed rules and existing signaling information. The receiving equipment uses the absence/presence of PDCCH, HARQ process number, and system frame number to autonomously determine the NDI flag value without requiring explicit transmission, thereby eliminating the signaling reliability problem while maintaining resource optimization.
2Loss of energy
If PDCCH signaling is avoided for initial transmission to conserve transmission resources, then transmission resource efficiency is improved, but NDI flag indication capability is worsened
Solution Approach 1:
The patent extracts the NDI flag indication function from the PDCCH signaling mechanism and implements it through alternative means. Instead of embedding NDI in PDCCH, the system derives NDI from the combination of PDCCH presence/absence status, HARQ process number, and system frame number. This extraction allows transmission resource conservation while preserving NDI information capability through a different signaling pathway.
Solution Approach 2:
The system performs preliminary agreement on NDI derivation rules during configuration phase, establishing the relationship between PDCCH presence/absence, HARQ process number, system frame number, and NDI flag value. This preliminary action enables the receiving equipment to correctly derive NDI without explicit signaling, preventing information loss while maintaining resource efficiency.
Data Source
AI summary
An apparatus 310 employable in a communication system configured to determine a value for a new data indicator for semi-persistently allocated or scheduled resources. In one embodiment, the apparatus 310 includes a processor 320 configured to receive a cell radio network temporary identifier indicating a semi-persistent scheduling. The processor 320 is also configured to treat a reception of data with a new data indicator flag in accordance with the semi-persistent scheduling as one of a persistent initial transmission if a value of the new data indicator flag is equal to a first predefined value, and a retransmission of semi-persistent scheduling data if the value of the new data indicator flag is equal to a second predefined value.