SPS Activation Determination in NB-IoT DCI Signaling
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Solution Overview
Problem
In Narrow Band Internet of Things (NB-IoT), determining the activation and deactivation of Semi-Persistent Scheduling (SPS) is challenging due to limitations in resource allocation and signaling overhead, particularly when reducing bits for MCS indexing, which can lead to resource wastage or increased data packet size.
Innovation Solution
The method involves implicitly indicating SPS activation and deactivation through radio network temporary identifiers, resource locations, or data channel positions within the Downlink Control Information (DCI), allowing for accurate determination and reduction of signaling overhead by using predefined C-RNTIs or resource locations, thereby improving resource utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If explicit SPS activation/deactivation fields are added to DCI, then SPS determination accuracy is improved, but signaling overhead increases
Solution Approach 1:
The patent merges SPS activation/deactivation indication with existing DCI fields by utilizing unused or reserved bits within the DCI structure. Specifically, it repurposes bits in the Resource Allocation (RA) field or introduces a compact SPS indication field that conveys both activation and deactivation states without adding significant overhead, thereby combining multiple functions into existing signaling structures.
Solution Approach 2:
The patent changes the parameter encoding by using specific bit patterns (e.g., NDI=0 with specific RA values or reserved bit combinations) to indicate SPS activation/deactivation. This allows the system to convey SPS state information by modifying existing parameter values rather than adding separate dedicated fields, thus improving determination accuracy while minimizing overhead.
2Productivity
If bits are reduced for MCS indexing, then signaling efficiency is improved, but resource allocation precision deteriorates
Solution Approach 1:
The patent applies partial action by reducing MCS bits only when SPS is activated, where the precise MCS value is less critical due to the periodic nature of SPS transmissions. For dynamic scheduling, full MCS precision is maintained. This selective reduction improves signaling efficiency for SPS while preserving resource allocation precision where needed.
Solution Approach 2:
The patent segments the MCS field into different precision levels based on scheduling type. For SPS activation, a reduced MCS field (e.g., 2-3 bits) is used, while dynamic scheduling retains the full MCS field (e.g., 4-5 bits). This segmentation allows signaling efficiency improvement for SPS without compromising resource allocation precision for time-critical dynamic transmissions.
Data Source
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AI summary
The embodiments of the present invention provide an SPS activation determination method and user equipment, specifically, the SPS activation determination method according to the embodiments of the present invention comprising: receiving downlink control information (DCI), the DCI implicitly indicating whether the SPS is activated; and determining whether the SPS is activated according to an indication of the received DCI. An SPS activation determination method according to another embodiment of the present invention, comprising: detecting a high-level control element in a data channel; and determining whether the SPS is activated according to an indication of the high-level control element. An SPS activation determination method according to further another embodiment of the present invention, comprising: receiving the downlink control information (DCI); and determining whether the SPS is activated according to the value of a specific field in the DCI and a correlation of activation and/or deactivation of the SPS.