Compact DCI Format for Short TTI Latency Reduction
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Solution Overview
Problem
Current wireless communication systems, particularly 3GPP LTE, face challenges in reducing packet data latency, which affects system responsiveness and throughput, and existing techniques such as pre-scheduling strategies and short transmission time intervals (TTI) do not fully address latency efficiency.
Innovation Solution
The method involves designing a downlink control information (DCI) format and resource allocation mechanisms to support short TTI, reducing control overhead by using compact DCI formats and dynamic bandwidth allocation, allowing for efficient coexistence with legacy TTI scheduling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If short TTI is used to reduce latency, then packet data latency is reduced, but control overhead increases
Solution Approach 1:
The patent segments the bandwidth into multiple groups and uses compact DCI formats that only indicate the selected bandwidth group rather than specifying all bandwidth details. This segmentation approach reduces the control information size while maintaining the ability to schedule short TTI transmissions across different bandwidth configurations.
Solution Approach 2:
The patent changes the DCI format parameters by using compact representations for bandwidth allocation. Instead of fully specifying bandwidth resources, the system uses reduced DCI formats that indicate bandwidth group indices, thereby reducing control overhead while supporting short TTI latency reduction.
2Productivity
If short TTI is used to reduce latency, then system responsiveness is improved, but device complexity increases
Solution Approach 1:
The patent designs DCI formats that can serve multiple functions - the same compact DCI structure is used for both short TTI scheduling and bandwidth group indication. This multi-functionality approach maintains system responsiveness while avoiding the need for separate complex control mechanisms.
Solution Approach 2:
The system dynamically selects between different DCI formats based on the scheduling needs. The eNodeB can flexibly choose compact DCI formats for short TTI transmissions or standard formats for legacy TTI, allowing the system to adapt to different latency requirements without permanently increasing device complexity.
3Productivity
If compact DCI formats are used to reduce control overhead, then radio resource efficiency is improved, but measurement precision of control information is reduced
Solution Approach 1:
The patent introduces bandwidth group tables as an intermediary structure that maps compact DCI indices to actual bandwidth configurations. This intermediary layer allows the system to use reduced DCI formats for efficiency while maintaining precise control through the predefined mapping relationships established in the bandwidth group tables.
Data Source
AI summary
A method and apparatus for receiving a physical downlink shared channel (PDSCH) for a short transmission time interval (TTI) in a wireless communication system is provided. A user equipment (UE) receives a downlink control information (DCI) format, which schedules the PDSCH for the short TTI in at least one group of bandwidths among an entire system bandwidth, from an eNodeB (eNB), and receives the PDSCH for the short TTI in the at least one group of bandwidth from the eNB. A length of the short TTI is less than 1 ms.