PRACH Random Access Procedure Latency Reduction
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Solution Overview
Problem
Current wireless communication systems face inefficiencies in performing random access procedures, particularly in unlicensed bands, due to challenges in channel access and resource allocation, leading to increased latency and reduced resource efficiency.
Innovation Solution
The method involves a communication device that transmits a physical random access channel (PRACH) in a random access channel occasion (RO), receives a physical downlink control channel (PDCCH) for scheduling a random access response (RAR), and configures the RAR with partial bits of a frame index, using a random access-radio network temporary identifier (RA-RNTI) masked with the PDCCH, to efficiently perform the random access procedure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a PRACH is transmitted in a random access channel occasion (RO) in unlicensed bands, then channel access can be performed, but latency increases and resource efficiency decreases due to channel access challenges
Solution Approach 1:
The system performs preliminary actions by pre-configuring multiple ROs with different time resources and pre-determining RA-RNTI values based on these RO configurations. This allows the UE to quickly identify available ROs and corresponding RA-RNTIs without extensive searching during the random access procedure, thereby reducing latency while maintaining reliable channel access in unlicensed bands
Solution Approach 2:
The system dynamically adapts the random access procedure by allowing flexible selection among multiple pre-configured ROs with different time resources. The UE can choose from multiple RA-RNTI values corresponding to different ROs, enabling dynamic optimization of channel access timing and reducing overall latency while maintaining access reliability
2Reliability
If traditional random access procedures are used in unlicensed bands, then channel access is possible, but resource allocation efficiency is reduced
Solution Approach 1:
The system segments the random access resources by configuring multiple ROs with different time resources and associating each with specific RA-RNTI values. This segmentation allows for more granular and efficient resource allocation, where different ROs can be utilized based on channel conditions and traffic requirements, thereby improving overall resource allocation efficiency while maintaining reliable channel access
Solution Approach 2:
The system changes the parameter of RA-RNTI configuration by determining RA-RNTI values based on RO configurations rather than using traditional fixed assignments. This parameter change enables more flexible and efficient resource allocation, allowing the system to optimize resource usage based on actual channel conditions and access requirements in unlicensed bands
Data Source
AI summary
A method and a device for transmitting and receiving signals in a wireless communication system according to one embodiment of the present invention are characterized by transmitting a PRACH on a RO, receiving, in response to the PRACH, a PDCCH for receiving a RAR, and receiving the RAR on the basis of the PDCCH, wherein the RAR includes a portion of the bits of a frame index of the RO on which the PRACH was transmitted.