2-Step Random Access Procedure for Wireless Signal Transmission
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Solution Overview
Problem
Current wireless communication systems face inefficiencies in performing random access procedures, particularly in unlicensed bands, leading to increased latency and reduced resource efficiency due to the need for sequential successful channel access in each step of the random access procedure.
Innovation Solution
A 2-step random access procedure is introduced, where the UE transmits a UL signal (MsgA) and the BS responds with a DL signal (MsgB), optimizing channel access by configuring specific time and frequency resources to minimize interference and ensure successful channel access in fewer steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional multi-step random access procedure is used, then channel access reliability is improved, but latency increases and resource efficiency deteriorates
Solution Approach 1:
The patent combines multiple random access steps into a single transmission opportunity. The UE transmits both preamble and data in one uplink message, and the network responds with a single downlink message containing both acknowledgment and data, reducing the number of sequential steps while maintaining reliability through unified transmission resources
Solution Approach 2:
The network pre-configures uplink and downlink resources for the 2-step random access procedure before the actual access occurs. This preliminary resource allocation eliminates the need for sequential resource negotiation in multiple steps, reducing latency while ensuring reliable access through predetermined resources
2Reliability
If a conventional multi-step random access procedure is used, then channel access reliability is improved, but resource efficiency deteriorates
Solution Approach 1:
The patent merges multiple resource usage opportunities into a single transmission event. By combining preamble transmission, data transmission, and acknowledgment reception into one 2-step exchange, the system reduces resource overhead and improves efficiency while maintaining access reliability through consolidated resource allocation
Solution Approach 2:
The uplink and downlink resources configured for the 2-step random access procedure serve multiple functions simultaneously - the uplink message carries both preamble and data, while the downlink message provides both acknowledgment and data transmission. This multi-functionality improves resource efficiency by eliminating the need for separate dedicated resources for each function
3Device complexity
If sequential channel access steps are performed, then interference management is simplified, but latency increases
Solution Approach 1:
The network performs preliminary configuration of uplink and downlink resources with specific time-frequency allocations before the random access occurs. This pre-configuration simplifies interference management by predetermined resource separation while reducing latency by eliminating sequential resource negotiation steps
Solution Approach 2:
The patent employs dynamic resource allocation where the network can flexibly configure uplink and downlink resources based on current channel conditions and traffic patterns. This dynamic approach simplifies interference management through adaptive resource separation while minimizing latency through optimized resource timing
Data Source
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AI summary
A method and apparatus for transmitting and receiving a signal in a wireless communication system, according to an embodiment of the present invention, transmit a PRACH through a specific RO from among a plurality of ROs on the basis of a selected SSB, wherein a starting RB index of the specific RO may be determined on the basis of (i) the lowest RB index of an RB set including the specific RO, (ii) a starting RB index of an RO located at the lowest frequency, and (iii) the lowest RB index of an RB set including the RO located at the lowest frequency.