Msg3 Repetition Signaling for NR Coverage and Latency
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Solution Overview
Problem
Current signaling mechanisms for Msg3 and physical uplink shared channel (PUSCH) repetitions in wireless communication systems, particularly in NR, face challenges in achieving optimal coverage and latency while efficiently managing resource consumption, due to ambiguities in frequency hopping flags and limitations in repetition behavior.
Innovation Solution
The proposed solution involves configuring the frequency hopping flag and transmission power control based on the aggregation or repetition factor, allowing for early stop of Msg3 repetitions and using a minimum Msg3 size of 72 bits to enhance coverage, with simulations showing that 72 bits with one repetition or HARQ retransmission can achieve similar coverage to 56 bits without repetition, impacting latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Msg3 repetitions are configured to enhance coverage, then coverage is improved, but latency increases and resource consumption increases
Solution Approach 1:
The patent introduces dynamic repetition configuration where the number of Msg3 repetitions is not fixed but can be adjusted based on coverage requirements. The network can dynamically configure repetition numbers through UL grants, allowing the system to adapt between low-latency single transmission and high-reliability repeated transmission modes depending on the operational context and coverage needs.
Solution Approach 2:
The patent changes the parameter of repetition number from a binary choice (repetition or no repetition) to a configurable variable. By introducing a repetition number field in the UL grant that can indicate different repetition counts, the system can optimize the balance between coverage and latency by adjusting this parameter based on actual network conditions and device requirements.
2Reliability
If Msg3 repetitions are configured to enhance coverage, then coverage is improved, but resource consumption increases
Solution Approach 1:
The patent applies partial repetition rather than always using full repetition. By configuring the repetition number to be greater than 1 only when coverage enhancement is actually needed, and allowing the network to determine the exact number of repetitions required, the system avoids unnecessary resource consumption while still providing coverage enhancement when necessary.
Solution Approach 2:
The dynamic configuration of repetition numbers allows the system to adjust resource allocation based on actual coverage needs. The network can configure higher repetition numbers only when coverage is a priority, and use lower repetition numbers or single transmission when resources should be conserved, thereby optimizing the balance between coverage enhancement and resource consumption.
3Reliability
If frequency hopping flag is used for Msg3 transmission, then frequency diversity is improved, but ambiguity in interpretation arises
Solution Approach 1:
The patent introduces a repetition number field as an intermediary element that clarifies the frequency hopping flag interpretation. By first determining the repetition number from the UL grant, the system can then correctly interpret the frequency hopping flag according to the specific repetition configuration, eliminating ambiguity in the signaling mechanism.
Solution Approach 2:
The patent changes the parameter space of the frequency hopping flag interpretation by introducing the repetition number as a conditioning parameter. The frequency hopping flag is no longer interpreted in isolation but rather in conjunction with the repetition number, allowing for unambiguous interpretation of the frequency hopping behavior based on the configured repetition characteristics.
4Reliability
If minimum Msg3 size is increased to 72 bits, then coverage is improved, but latency increases
Solution Approach 1:
The patent applies partial size increase rather than always using the maximum Msg3 size. By configuring a minimum size of 72 bits rather than always transmitting the full size, the system achieves improved coverage for critical transmissions while avoiding unnecessary latency for smaller messages that can be transmitted efficiently with the standard 56-bit format.
Data Source
AI summary
A method, network node and wireless device, WD, providing signaling mechanisms for enabling repetitions of messages related to random access, RA, are disclosed. According to one aspect, a network node transmits an indication of a number of zero or more repetitions of a message related to RA to be transmitted by the WD in response to a random access response, RAR, message transmitted to the WD. The network node further receives at least one message related to RA.