Downlink Control Channel Design for Dynamic TTI Switching
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Solution Overview
Problem
Current wireless communication systems face challenges in efficiently managing control channels for shared wireless communications, particularly in switching between mini-slot and slot-based transmissions, which can lead to resource wastage and increased latency.
Innovation Solution
The proposed solution involves a method where a base station and user equipment (UE) monitor a shared radio frequency spectrum band to switch between mini-slot and slot-based transmissions based on signaling, with the base station transmitting a downlink control channel indicating the change in transmission mode, allowing for efficient resource allocation and reduced latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the system uses fixed transmission modes (either mini-slot or slot-based), then the system complexity is reduced and easier to implement, but the adaptability to different communication scenarios deteriorates
Solution Approach 1:
The patent implements dynamic transmission mode switching where the base station can transition between mini-slot-based and slot-based transmission modes based on channel conditions and traffic requirements. The UE is configured to monitor for mode indication signaling that dynamically changes the transmission mode, allowing the system to adapt to varying communication scenarios while maintaining manageable complexity through standardized switching procedures.
Solution Approach 2:
The system changes the transmission mode parameter (from mini-slot-based to slot-based or vice versa) based on signaling received from the base station. This parameter change allows the system to adapt to different communication scenarios by adjusting the TTI duration and structure, thereby improving versatility without requiring complete system redesign.
2Adaptability or versatility
If the system switches between mini-slot and slot-based transmissions using traditional methods, then the adaptability to different scenarios is improved, but the transmission latency increases and resource utilization deteriorates
Solution Approach 1:
The base station sends mode indication signaling in advance to notify the UE of upcoming transmission mode changes. This preliminary action allows the UE to prepare for the mode switch without waiting for the actual transmission to begin, thereby reducing latency. The signaling is transmitted during the current transmission mode, giving advance notice of the upcoming change.
Solution Approach 2:
The patent enables rapid transmission mode switching by using compact signaling mechanisms that allow the system to quickly transition between mini-slot and slot-based modes. The mode indication can be conveyed through efficient signaling methods that minimize the time required for mode transition, allowing the system to rush through the switching process and adapt quickly to changing conditions without excessive latency.
3Reliability
If the system uses separate control channels for different transmission modes, then the reliability of control signaling is improved, but the device complexity and resource overhead increase
Solution Approach 1:
The patent employs a universal control channel approach where the same downlink control channel structure is used for both mini-slot-based and slot-based transmission modes. The base station transmits mode indication signaling through the existing control channel infrastructure, which serves multiple functions: conveying scheduling information, indicating transmission mode changes, and providing other control directives. This multi-functionality maintains reliability while avoiding the complexity of separate dedicated control channels for each mode.
Data Source
AI summary
Methods, systems, and devices for wireless communication are described that may enable a user equipment (UE) to monitor a shared spectrum to receive control signaling and data transmissions associated with different transmission time intervals (TTIs). For example, a base station may communicate with a UE according to a first transmission mode during a first, shortened TTI. The base station may transmit a downlink control channel for a shortened TTI based on a subset of a number of blind decodes or control channel elements. Additionally, a downlink control channel for a shortened TTI may contain grants for multiple TTIs. In some cases, the base station may transmit a signaling to the UE via a reference signal, downlink control channel, or radio resource control which may indicate a change from the shortened-TTI transmission mode to a transmission mode with a TTI duration that is longer than the first, shortened TTI duration.