Carrier Scheduling Reduces PDCCH Search Space Collisions
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In carrier aggregation (CA) technology, especially in LTE-Advanced, the increased number of activated secondary cells leads to a sharp rise in PDCCH blind detection, causing resource congestion and search space collisions, which reduces the success rate of blind detection and affects carrier scheduling performance.
Innovation Solution
A method is introduced where, when the overlapping ratio of search spaces exceeds a threshold, a UE-specific DCI format is selected, marked with an invalid CIF, and scheduled on an anchor carrier, while remaining DCI formats without CIF are scheduled on other carriers, adopting a non-cross-carrier scheduling approach to reduce conflicts and congestion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If cross-carrier scheduling with CIF is used to schedule multiple carriers, then carrier scheduling capability is improved, but PDCCH resource congestion and search space collision increase
Solution Approach 1:
The patent segments the DCI formats into two categories: UE-specific DCI formats (0, 1A, 2A) that carry CIF and are scheduled on anchor carrier, and other DCI formats that do not carry CIF and are scheduled on non-anchor carriers. This segmentation separates the scheduling functions to reduce search space overlap and PDCCH resource congestion while maintaining multi-carrier scheduling capability.
2Productivity
If the number of activated Scells is increased to enhance carrier aggregation, then network capacity is improved, but PDCCH blind detection complexity increases sharply
Solution Approach 1:
The patent extracts the CIF-containing UE-specific DCI formats from the general DCI format set and schedules them separately on the anchor carrier. This extraction reduces the search space size on non-anchor carriers, thereby reducing PDCCH blind detection complexity while maintaining the ability to schedule multiple carriers through carrier aggregation.
3Ease of manufacture
If search space is determined by formula (1) with CCE_start and aggregation level L, then search space definition is standardized, but search space collision probability increases with more carriers
Solution Approach 1:
The patent applies different scheduling approaches to different DCI formats and different carriers. UE-specific DCI formats with CIF are scheduled on the anchor carrier using standard search space definition, while other DCI formats are scheduled on non-anchor carriers without CIF. This local differentiation reduces search space collision probability and improves blind detection success rate while maintaining standardization.
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
The present invention provides a carrier scheduling method, device and system for carrier aggregation. The method may include: within a current transmission time interval (TTI), when the number of times of overlapping between search spaces of all user equipment (UEs) to be scheduled satisfies a preset determination condition, selecting a UE-specific downlink control information (DCI) format; marking the selected UE-specific DCI format, and setting scheduling of a physical downlink shared channel (PDSCH) corresponding to the UE-specific DCI format onto an anchor carrier component; setting physical downlink control channels (PDCCHs) corresponding to remaining DCI formats other than the UE-specific DCI format onto carrier components for scheduling the PDSCHs corresponding to the remaining DCI formats; and sending the set anchor carrier component and the carrier components set corresponding to the remaining DCI formats to the UEs to be scheduled.