Terminal Random Access Control for Multi-TTI Cells
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Future wireless communication systems, such as LTE Rel. 13 and 5G, face challenges in providing sufficient communication service when using the traditional 1 ms Transmission Time Interval (TTI), especially when user terminals are connected to cells with different TTIs, as it complicates the control of the random access procedure.
Innovation Solution
A user terminal with a control section that manages communication across cells with different TTIs, including a transmission section for sending a random access preamble and a reception section for receiving the response signal, allowing the control section to receive the response signal in a second cell, enabling appropriate random access even when TTIs are shortened.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a shortened TTI is used to reduce transmission time, then communication speed is improved, but the complexity of controlling the random access procedure increases
Solution Approach 1:
The patent segments the random access procedure into distinct steps (preamble transmission, response reception, timing advance application) with specific TTI alignment requirements for each step. This segmentation allows the system to manage the complexity of shortened TTI control by handling each step independently with defined timing relationships.
Solution Approach 2:
The patent introduces dynamic timing adjustment mechanisms where the terminal device adjusts its timing based on received timing advance values. The system dynamically adapts the TTI boundaries and synchronization timing to accommodate shortened TTI configurations while maintaining proper random access procedure control.
2Adaptability or versatility
If a user terminal is connected to cells with different TTIs to enable carrier aggregation, then communication versatility is improved, but the difficulty of detecting and measuring random access timing increases
Solution Approach 1:
The patent uses the downlink timing of the serving cell as an intermediary reference for uplink random access preamble transmission timing. This intermediary reference allows the terminal to coordinate random access across cells with different TTIs by aligning to a common timing baseline, simplifying the detection and measurement process.
Solution Approach 2:
The patent changes the timing parameters of the random access procedure based on the TTI configuration of the target cell. The terminal adjusts the preamble transmission timing and response reception timing according to the specific TTI length of each cell, enabling versatile multi-cell operation while maintaining accurate timing detection.
Data Source
AI summary
This invention aims to appropriately perform random access even when a shortened TTI is used. A user terminal includes a control section which controls communication using cells including at least two cells having different TTIs (Transmission Time Intervals), a transmission section which transmits a random access preamble, and a reception section which receives a response signal to the random access preamble, wherein the control section performs control to receive in a second cell, the response signal to the random access preamble transmitted in a first cell.