2-Step Random Access Window Timing for PRACH–PUSCH Mapping
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing 4G wireless communication systems face challenges in meeting the increasing demand for high-speed data services, and the 5G communication systems, when applied to IoT networks, suffer from inefficiencies in the 2-step random access procedure, particularly when PRACH occasions are not mapped to valid PUSCH occasions, leading to increased latency and incomplete random access.
Innovation Solution
A method and system for a 2-step random access procedure in wireless communication systems, where a terminal transmits a message A (MsgA) and starts a window for receiving a physical downlink control channel (PDCCH) of message B (MsgB), identifying the symbol based on whether a physical uplink shared channel (PUSCH) is transmitted in MsgA with a physical random access channel (PRACH), and detects downlink control information during the window, thereby enhancing synchronization and reducing latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PRACH occasions are not mapped to valid PUSCH occasions in 2-step random access procedure, then the random access process becomes incomplete and requires fallback to 4-step RA, but this increases latency and reduces access efficiency
Solution Approach 1:
The patent applies preliminary action by having the UE check whether PRACH occasions are mapped to valid PUSCH occasions before initiating the random access procedure. This advance verification prevents selection of invalid PRACH occasions, ensuring the random access can complete in 2 steps without fallback to 4-step procedure, thereby reducing latency while maintaining reliability
2Productivity
If the UE selects invalid PRACH occasions without proper identification, then the random access procedure cannot be completed efficiently, but implementing proper identification and validation mechanisms increases system complexity
Solution Approach 1:
The patent implements feedback by having the network provide mapping information indicating which PRACH occasions are associated with valid PUSCH occasions. The UE uses this feedback to select appropriate PRACH occasions, ensuring efficient random access completion without requiring complex validation mechanisms at the UE side, thus improving productivity while limiting complexity increase
Data Source
AI summary
A method performed by a terminal of a 2-step random access procedure in a wireless communication system is provided. The method includes transmitting a message A (MsgA) for the 2-step random access procedure, starting a window at a symbol for receiving a physical downlink control channel (PDCCH) of a message B (MsgB), wherein the symbol is identified based on whether a physical uplink shared channel (PUSCH) is transmitted in the MsgA with a physical random access channel (PRACH), and detecting downlink control information on the PDCCH of the MsgB during the window.