Uplink Random Access Msg3 Repetition for Coverage Extension
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Solution Overview
Problem
Current communication systems face challenges in extending the coverage of uplink signals and channels, particularly in 5G NR systems using higher frequency bands, where the existing techniques for repeated transmission of eMBB and URLLC traffic do not efficiently manage latency and error rates, leading to suboptimal performance in coverage extension.
Innovation Solution
The method involves a terminal and base station operation where the terminal receives configuration information for random access procedures, allowing repeated transmission of Msg3 based on specific conditions, with the number of repetitions determined by the base station and indicated through DCI or RRC signaling, enabling flexible resource allocation and phase/power continuity of DM-RSs to enhance channel estimation and multiplexing gains.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If repeated transmission is used to extend coverage, then reliability is improved, but latency increases
Solution Approach 1:
The patent implements periodic repeated transmission of uplink signals across multiple slots with configured periodicity. The network configures repetition patterns where the same uplink data is transmitted periodically in time domain, allowing the receiver to accumulate multiple copies for improved reliability while controlling the overall transmission duration through configured repetition counts and slot offsets.
2Reliability
If lower MCS is used to reduce error rate, then reliability is improved, but transmission efficiency deteriorates
Solution Approach 1:
The patent applies partial repetition by transmitting uplink data multiple times with selective redundancy. Instead of always using the most robust low-MCS scheme, the system transmits at higher MCS with repeated copies, allowing the receiver to select the best quality copy or combine copies for decoding. This achieves reliability through selective repetition rather than through excessive use of low-efficiency modulation schemes.
3Device complexity
If time resource allocation includes only first slot resources, then device complexity is reduced, but coverage extension capability deteriorates
Solution Approach 1:
The patent implements preliminary configuration of multi-slot repetition parameters through higher-layer signaling (RRC or MAC CE). The network pre-configures repetition factors, slot offsets, and resource patterns before actual transmission occurs. This allows the terminal to automatically perform repeated transmissions across multiple slots without real-time scheduling complexity, achieving both simplified device operation and enhanced coverage extension capability.
Data Source
AI summary
An operation method of a terminal in a communication system may comprise receiving first random access (RA) configuration information and second RA configuration information from a base station; transmitting a Msg1 to the base station based on the second RA configuration information; receiving a Msg2, which is a response to the Msg1, from the base station; and repeatedly transmitting a Msg3 K times to the base station.