LTE Subframe Slot Symbol Mapping for TTI Compatibility
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Solution Overview
Problem
The existing LTE communication systems face challenges in supporting a UE compatible with shortened Transmission Time Intervals (TTI) such as TTI=1 slot or TTI=1 symbol, while maintaining backward compatibility with legacy UEs on the same carriers.
Innovation Solution
The communication system maps the shared channel of the first communication terminal device to physical resources per subframe and maps the shared channel of the second communication terminal device, with a shorter TTI, to physical resource blocks within the same region of physical resources as the first device, allowing both to coexist in the same subframe.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the Transmission Time Interval (TTI) is shortened to 1 slot or 1 symbol, then the data transmission speed is improved, but the compatibility with legacy UEs deteriorates
Solution Approach 1:
The subframe is divided into multiple slots, and each slot is further divided into multiple symbols. The patent segments the physical resources in this way to allow different TTI lengths (1 subframe, 1 slot, or 1 symbol) to coexist within the same carrier. This segmentation enables legacy UEs to use 1 subframe TTI while LR-UEs can use shorter TTIs, resolving the contradiction between transmission speed and compatibility.
Solution Approach 2:
The patent introduces dynamic TTI selection where the TTI length can be changed based on UE capability and network configuration. The eNodeB can dynamically determine whether to use 1 subframe, 1 slot, or 1 symbol TTI for different UEs on the same carrier. This dynamic adjustment allows the system to adapt between legacy and advanced UE requirements, maintaining both compatibility and transmission speed.
2Adaptability or versatility
If multiple TTIs are supported on the same carrier, then the system versatility is improved, but the resource mapping complexity increases
Solution Approach 1:
The patent segments the physical resources into slots and symbols in a hierarchical manner. By dividing the subframe into slots and slots into symbols, the system creates a standardized framework that can accommodate different TTI lengths without requiring completely separate resource mapping mechanisms. This segmentation reduces the complexity of managing multiple TTIs by providing a common structural basis.
Solution Approach 2:
The patent applies local quality by allowing different TTI configurations to coexist within the same carrier, where each UE or resource block can have its specific TTI length assigned based on its capabilities. The eNodeB can locally determine the appropriate TTI for each UE without affecting the entire carrier, thus managing complexity through localized configuration rather than global reconfiguration.
Data Source
AI summary
A communication system is configured to communicate using at least one subframe, slots included in the subframe, and symbols included in each of the slots. The communication system includes a terminal configured to transmit a physical uplink shared channel (PUSCH) being mapped in units of symbols by a slot in time domain, and a base station configured to receive the physical uplink shared channel transmitted from the terminal.