Dynamic Cell Scheduling via Single DCI for Reliable HARQ
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Solution Overview
Problem
Current telecommunication systems face challenges in scheduling Physical Downlink Shared Channels (PDSCHs) across multiple cells using a single Downlink Control Information (DCI), especially when implementing Hybrid Automatic Repeat Request (HARQ) or multiple-input, multiple-output (MIMO) transmissions, leading to potential data transmission failures due to SCell deactivation or dormant states.
Innovation Solution
A method where a base station dynamically switches the cell for scheduling transmissions, using the same control information (DCI) to transmit data units or signaling across different cells, ensuring continued communication even if the UE stops monitoring an SCell by re-scheduling HARQ transmissions on a PCell.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a base station configures an SCell for cross-carrier scheduling on the PCell, then the UE can be scheduled across multiple cells, but the UE may stop monitoring PDCCH on the SCell when it becomes dormant or deactivated, resulting in failure to transmit data units or signaling
Solution Approach 1:
The base station dynamically switches the scheduling cell between PCell and SCell based on the operational state of the SCell. When SCell is active, it schedules PDSCH on SCell; when SCell becomes dormant or deactivated, the base station switches to schedule PDSCH on PCell using PDCCH from PCell, ensuring continuous reliable transmission
Solution Approach 2:
The PCell acts as an intermediary backup scheduling cell. When the primary SCell scheduling path becomes unavailable due to dormant/deactivated state, the PCell with its PDCCH serves as the intermediary to transmit control information and schedule PDSCH, maintaining communication reliability
2Device complexity
If the base station uses a single DCI to schedule PDSCH across multiple cells, then control information efficiency is improved, but it becomes unclear whether this is possible when implementing HARQ or MIMO transmissions
Solution Approach 1:
The single DCI format is designed to be universal and multi-functional, capable of scheduling PDSCH on multiple cells simultaneously and supporting both HARQ and MIMO operations through configurable fields. The DCI includes carrier indicator fields, HARQ process indicators, and MIMO parameters that can be adapted for different transmission scenarios across multiple cells
Solution Approach 2:
The DCI parameters are configured to support multi-cell scheduling with HARQ and MIMO. The base station sets specific parameter values in the DCI including carrier indicator field (CIF) values for different cells, HARQ process numbers, redundancy versions for HARQ, and MIMO-related parameters such as antenna port indicators and layer allocation, enabling flexible adaptation to different transmission requirements
Data Source
AI summary
A base station transmits, the a secondary cell (SCell), a control indicator indicating resources for communicating an information unit between the UE and the base station. The base station then communicates the first information unit according to the first control indicator in a primary cell (PCell).