Semi-Persistent Scheduling False Alarm Reduction via Augmented CRC
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Solution Overview
Problem
Current wireless communication systems experience false alarms due to incorrect validation of grants on the physical downlink control channel (PDCCH), particularly in semi-persistent scheduling, leading to persistent errors and reduced system efficiency.
Innovation Solution
Implementing an augmented cyclic redundancy check (CRC) mechanism by imposing constraints on the PDCCH payload to verify the validity of grants, thereby reducing false alarms and enhancing error checking robustness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a 16-bit CRC check is used on PDCCH formats, then error detection capability is provided, but false alarms occur when X-CRC matches CRC despite the PDCCH not being meant for that UE
Solution Approach 1:
The patent segments the validation process into two independent parts: a 16-bit CRC check and an additional constraint verification on specific payload bits. This segmentation allows the system to maintain the original error detection capability while adding a secondary validation layer that specifically targets false alarm reduction without interfering with the primary CRC function.
Solution Approach 2:
The patent introduces an intermediary validation mechanism (constraint checking) that acts as a mediator between the CRC check and the final grant acceptance decision. This intermediary layer verifies additional payload characteristics to confirm the authenticity of the grant, thereby reducing false alarms while preserving the reliability provided by the CRC.
2Productivity
If semi-persistent scheduling is implemented to improve system capacity, then resource assignment overhead is reduced, but false alarms cause persistent errors that reduce system efficiency
Solution Approach 1:
The patent applies preliminary validation actions by checking constraints on PDCCH payload bits before the UE acts on the grant. This preliminary check occurs during the validation phase, allowing the system to reject potentially false grants before they cause persistent scheduling errors, thereby maintaining both the efficiency gains of SPS and the reliability of error-free operation.
3Measurement precision
If constraint verification on PDCCH payload is added to reduce false alarms, then false alarm rate decreases, but device complexity increases
Solution Approach 1:
The patent applies local quality by focusing constraint verification on specific portions of the PDCCH payload rather than the entire message. By selecting particular bits or fields for constraint checking, the system achieves effective false alarm reduction with minimal additional processing complexity, as only localized portions of the data require enhanced validation.
Data Source
AI summary
A scheduled data communication system of an access node and terminal supports recurring communications of small data amounts such as Voice over IP (VoIP). In order to make error checking more robust in a random access response (RAR), such as for semi-persistent scheduling (SPS) for VoIP, a portion of a grant or assignment payload has a constraint imposed that can be verified as a condition precedent to determining a valid grant or assignment rather than only relying upon a validity check field, such as a cyclic redundancy check (CRC). Thereby, incorrect validation of a grant or assignment is avoided for dynamic scheduling or for semi-persistent scheduling, the latter causing a persistent error.