Downlink Control Information Transmission in Variable TTI Systems
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Solution Overview
Problem
Current mobile communication systems, such as LTE, lack a solution for transmitting downlink control information when the length of a Transmission Time Interval (TTI) is variable, which hinders the support for dynamic resource allocation and diverse service demands in future mobile communication networks.
Innovation Solution
A method and apparatus for transmitting and detecting downlink control information by determining reserved resources within a dynamic TTI, where the length can vary, allowing for scheduled UEs to transmit data in allocated resource regions, with specific frequency and time positions designated for downlink control information, enabling efficient resource utilization across varying TTI lengths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If fixed TTI length is used in LTE system, then downlink control information transmission is straightforward, but the system cannot support dynamic resource allocation and diverse service demands
Solution Approach 1:
The patent applies dynamics by making the TTI length variable rather than fixed. The base station can dynamically adjust the TTI length according to different service requirements, enabling the system to adapt to diverse service demands while maintaining a structured approach to downlink control information transmission in both short and long TTI scenarios
Solution Approach 2:
The patent segments the downlink transmission into distinct short TTI and long TTI scenarios with separate resource allocation mechanisms. By dividing the control information transmission into different patterns for different TTI lengths, the system manages complexity through structured segmentation rather than attempting a unified approach
2Productivity
If variable TTI length is implemented, then dynamic resource allocation is enabled, but there is no established method for downlink control information transmission
Solution Approach 1:
The patent applies local quality by defining specific resource allocation patterns for different TTI lengths. Rather than using a uniform approach, the system tailors the downlink control information transmission characteristics to local requirements - using different resource element group configurations, search space definitions, and detection timing for short versus long TTIs
Solution Approach 2:
The patent changes key parameters including TTI length, resource element group size, search space configuration, and detection timing based on the selected TTI type. These parameter adjustments enable efficient resource allocation while providing clear detection rules for each scenario, reducing the difficulty of downlink control information detection
3Loss of information
If blind detection is used for PDCCH, then UE can find its control information, but energy consumption increases due to searching multiple positions
Solution Approach 1:
The patent applies preliminary action by pre-configuring search spaces and resource allocations for both short and long TTI scenarios. The base station informs UEs in advance about where to find control information and what detection parameters to use, allowing UEs to perform targeted blind detection rather than exhaustive searching, thereby reducing energy consumption while maintaining detection reliability
Data Source
AI summary
Disclosed are a method and apparatus for transmitting and detecting downlink control information. The method involves determining a state of resource allocation in a downlink transmission time period, the resource allocation corresponds to allocation of at least one downlink transmission resource region; and transmitting downlink control information on a preset resource in the at least one downlink transmission resource region, the downlink control information being used for scheduling at least one terminal to perform data transmission in the downlink transmission resource region. The method also involves detecting the downlink control information on the preset resource in the downlink transmission time period; determining, according to the detected downlink control information, a data transmission region indicated by the downlink control information; and detecting follow-up downlink control information according to the data transmission region. By using the present invention, downlink control information can be transmitted at a fixed position in each downlink transmission time period, and multiple transmission time intervals of different lengths are supported, so that rich service types in the future can be better supported.