Unified Two-Stage DCI Framework for Mobile Control Channels
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Solution Overview
Problem
Current Long-Term Evolution (LTE) and New Radio (NR) multi-link operation frameworks face increased blind decoding complexity and downlink control information (DCI) overhead due to the 1-to-1 association between component carriers (CCs) and cells, leading to user-perceived throughput degradation and scheduling inefficiency.
Innovation Solution
A unified two-stage DCI framework is proposed, where a compact first-stage DCI delivers scheduling information for a second-stage DCI, allowing for reduced blind decoding complexity and DCI overhead by separating scheduling and non-scheduling information, enabling efficient PDSCH reception and PUSCH transmission across multiple carriers or cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the UE's blind decoding capability is implemented to support the maximum number of BD attempts per slot increases with the real number of configured CCs/cells, then the scheduling coverage is improved, but the BD complexity and UE cost will inevitably increase
Solution Approach 1:
The patent segments the control information into two stages: first-stage DCI for initial scheduling decisions and second-stage DCI for detailed resource allocation. This segmentation allows the UE to perform blind decoding only on the first-stage DCI with a fixed limited number of attempts, while the second-stage DCI is received based on the first-stage indication, thereby reducing BD complexity while maintaining scheduling coverage for multiple CCs/cells.
Solution Approach 2:
The first-stage DCI acts as an intermediary that indicates the presence and location of the second-stage DCI. This intermediary structure allows the system to maintain fixed BD complexity for the first stage while enabling flexible scheduling across multiple CCs/cells through the second stage, thus resolving the contradiction between adaptability and device complexity.
2Loss of information
If there are common bit-fields in the respective downlink control information (DCI) for each configured CC/cell in CA, then the scheduling information is complete, but the DCI overhead increases significantly
Solution Approach 1:
The patent extracts the common scheduling information into the first-stage DCI, which is transmitted once and applies to multiple CCs/cells. The second-stage DCI contains only the specific per-CC/cell allocation details. This extraction eliminates the redundancy of transmitting common bit-fields multiple times across different DCIs, significantly reducing DCI overhead while maintaining complete scheduling information.
Solution Approach 2:
The patent merges the common scheduling information for multiple CCs/cells into a single first-stage DCI message. Instead of having separate DCI messages with duplicate common fields for each CC/cell, the common information is combined once in the first stage, and only the variable per-CC/cell specific information is transmitted in the second stage, thereby reducing overall DCI overhead.
3Ease of operation
If one CC is associated with one cell in the current CA framework, then the mapping is simple, but the L1 signalling complexity and overhead increase with the number of CCs/cells
Solution Approach 1:
The patent makes the first-stage DCI universal by allowing it to schedule multiple CCs/cells simultaneously through a unified indication mechanism. The first-stage DCI contains common scheduling parameters that apply to multiple CCs/cells, and the second-stage DCI provides specific allocations. This multi-functional approach maintains simple mapping relationships while reducing L1 signalling complexity compared to the traditional 1-to-1 association model.
Data Source
AI summary
Various solutions for providing a unified control channel framework in mobile communications are described. An apparatus receives a first-stage downlink control information (DCI) from a network node. The first-stage DCI indicates first scheduling information associated with a second-stage DCI. Then, the apparatus receives the second-stage DCI from the network node according to the first scheduling information. The second-stage DCI indicates second scheduling information associated with one or more carriers or cells or indicates non-scheduling information associated with one or more features. Also, the apparatus performs operations including either one of the following: (1) performing a PDSCH reception or a PUSCH transmission on at least one of the one or more carriers or cells according to the second scheduling information; and (2) applying the non-scheduling information in an event that the apparatus supports at least one of the one or more features.