PRACH Occasion Selection for Extended Uplink Random Access
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Solution Overview
Problem
Existing wireless communication systems face challenges in extending the reach of nodes, particularly in scenarios requiring high-frequency bands and diverse communication services like eMBB, URLLC, and mMTC, where efficient uplink transmission and random access are crucial but often limited by distance and latency issues.
Innovation Solution
The method involves measuring received signal strength, determining PRACH transmissions based on RSRP, selecting valid ROs within SSB-RO association periods, and considering time offsets to optimize PRACH transmission, thereby enabling repetitive and coordinated channel access to enhance reach and reduce latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If terminals use conventional random access methods in high-frequency bands, then communication setup can be initiated, but the reach is limited and latency increases due to distance constraints
Solution Approach 1:
The random access procedure is divided into multiple transmission attempts with each attempt using a different RO. The terminal segments the access process into repeated trials, where each trial can be independently evaluated and retransmitted if unsuccessful, thereby extending the effective reach through persistent attempts
Solution Approach 2:
The network pre-configures multiple ROs and their associations with SSBs before the terminal needs to access. This preliminary setup allows the terminal to immediately select from available ROs without additional signaling delay, reducing access latency while maintaining extended reach capability
2Reliability
If multiple PRACH transmissions are performed to extend reach, then connectivity over longer distances is achieved, but the complexity of managing transmission occasions increases
Solution Approach 1:
The terminal monitors for random access responses after each PRACH transmission and uses this feedback to determine whether to continue with retransmissions or stop. This feedback mechanism provides clear termination criteria that simplifies the management of multiple transmissions while maintaining high connectivity reliability
Solution Approach 2:
The terminal dynamically adjusts its random access strategy by selecting from multiple configured ROs based on current conditions such as detected SSBs and previous transmission outcomes. This dynamic selection process manages complexity by adapting to real-time conditions rather than using fixed repetitive patterns
Data Source
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AI summary
An apparatus for extending reach of a node in a wireless communication system and a method thereof are proposed. The apparatus and method generally relates to uplink transmission technology of a terminal in the wireless communication system and, more particularly, to uplink transmission technology of a terminal having multiple channels in the wireless communication system. A method of operating a terminal in a wireless communication system includes a process of measuring RSRP for an SSB received from a BS, a process of determining the number of transmissions of a PRACH on the basis of the RSRP, a process of selecting valid ROs for transmitting the PRACH among ROs included in at least one of an SSB-RO association period or an SSB-RO association pattern period, which is corresponding to the SSB, and a process of selecting an RO group for PRACH transmission among the valid ROs by considering a time offset.