RACH Occasion Configuration for Low-Overhead Two-Step Access
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Solution Overview
Problem
Conventional two-step RACH procedures in wireless communications systems incur high overhead and increased conflict risk due to the transmission of data or control information in a physical uplink shared channel (PUSCH), leading to potential RACH failures.
Innovation Solution
A UE transmits data or control information along with a RACH preamble in a RACH occasion within the first RACH message, eliminating the need for PUSCH transmission when the data volume is low, and minimizing resource conflicts by distributing the data across RACH occasions and PUSCH when volume is high.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If data or control information is transmitted in a PUSCH during two-step RACH procedure, then reliable data transmission is achieved, but overhead (CRC, channel coding, higher layer header) increases and resource conflicts increase
Solution Approach 1:
The patent segments the data transmission process by separating small data packets (transmitted in RACH occasion) from large data packets (transmitted in PUSCH). This segmentation allows the system to avoid unnecessary PUSCH overhead for small data while maintaining reliability for larger data transmissions.
Solution Approach 2:
The patent applies partial action by using RACH occasion for data transmission only when the data size is small (below a threshold). When data size exceeds the threshold, the system transitions to using PUSCH. This partial application of RACH occasion for data transmission eliminates unnecessary overhead while maintaining the option for reliable transmission when needed.
2Quantity of substance
If PUSCH is used to transmit data or control information, then sufficient data capacity is provided, but the chance of RACH message conflicts increases
Solution Approach 1:
The patent segments data transmission into two paths: RACH occasion for small data (reducing conflict risk) and PUSCH for large data (providing sufficient capacity). This segmentation allows the system to minimize conflicts by using the lower-capacity RACH occasion only when necessary, while reserving PUSCH for when higher capacity is needed.
Solution Approach 2:
The patent changes the transmission parameter (channel selection) based on data size. When data size is below a threshold, the system changes to using RACH occasion instead of PUSCH. This parameter change dynamically adjusts the transmission method to optimize between conflict risk and data capacity based on actual needs.
3Reliability
If PUSCH transmission is performed for small data, then data transmission is ensured, but overhead is unnecessarily increased
Solution Approach 1:
The patent applies partial action by using the more efficient RACH occasion for small data transmissions where full PUSCH overhead is not justified. The system determines data size and selectively applies the appropriate transmission method, avoiding excessive overhead for small data while ensuring reliable transmission when needed.
Solution Approach 2:
The patent changes the transmission parameter based on data size threshold. When data size is small, the system switches to RACH occasion transmission which has lower overhead. This parameter change optimizes energy consumption by avoiding unnecessary PUSCH overhead for small data transmissions while maintaining transmission reliability.
Data Source
AI summary
Methods, systems, and devices for wireless communication are described. Generally, the described techniques provide for efficiently transmitting data and control information in a first RACH message to a base station as part of a two-step RACH procedure. In particular, rather than or in addition to transmitting data and control information in a physical uplink shared channel (PUSCH) in the first RACH message, a user equipment (UE) may transmit the data and control information along with a RACH preamble in a RACH occasion in the first RACH message (e.g., when the number of bytes of data or control information to be transmitted is low). Using these techniques, in some instances, the UE may transmit the data and control information in a first RACH message without transmitting the PUSCH, and the overhead associated with transmitting the PUSCH may be eliminated.