NR Coverage Enhancement Using Repetition and Frequency Diversity
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Solution Overview
Problem
Existing NR systems face challenges in extending coverage, particularly for downlink channels like PDSCH and uplink channels like PUSCH, especially in rural deployments where wireless devices are far from the serving base station, and fail to support coverage extension for PUSCH carrying Msg3 during random access due to the absence of RRC signaling.
Innovation Solution
A serving base station configures coverage-limited UE with parameters for a coverage enhancement mode using RRC signaling, enabling time domain repetitions and frequency hopping for PDSCH, PUSCH, and PUCCH channels to enhance coverage, including configuration for PUSCH Msg3 transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a coverage-limited UE operates in conventional NR mode, then the system maintains standard communication protocols, but the UE experiences poor coverage and limited connectivity
Solution Approach 1:
The patent implements dynamic mode switching between conventional NR mode and coverage enhancement mode based on real-time signal conditions. The UE monitors reference signals and dynamically transitions between modes to optimize coverage reliability while maintaining protocol compatibility, resolving the contradiction between reliability and adaptability.
Solution Approach 2:
The patent changes key transmission parameters such as repetition factor, time resource allocation, and frequency resources when entering coverage enhancement mode. These parameter modifications enable the UE to achieve reliable communication in poor coverage areas while maintaining the ability to switch back to standard mode when conditions improve.
2Reliability
If the UE enters coverage enhancement mode with repeated transmissions, then coverage reliability improves, but transmission time and latency increase
Solution Approach 1:
The patent employs periodic repeated transmissions of downlink and uplink channels with configurable repetition factors. This periodic action enables reliability through multiple transmission attempts while allowing the system to optimize the balance between reliability improvement and time consumption by adjusting the repetition factor based on channel conditions.
Solution Approach 2:
The patent maintains continuous communication through overlapping transmissions where downlink and uplink channels are transmitted simultaneously in different time resources. This continuity reduces the overall time penalty by ensuring that transmission activities overlap rather than sequence sequentially, maintaining useful action throughout the coverage enhancement process.
3Adaptability or versatility
If the base station configures coverage enhancement parameters dynamically, then adaptability to moving UEs improves, but system complexity increases
Solution Approach 1:
The patent implements feedback mechanisms where the UE reports coverage conditions and signal quality to the base station, which then dynamically adjusts coverage enhancement parameters. This feedback loop enables adaptive configuration for moving UEs while managing complexity through automated parameter adjustment based on real-time conditions.
Solution Approach 2:
The patent designs a universal coverage enhancement mode that can be activated for any UE regardless of specific location or channel conditions. The multi-functional parameter set handles various scenarios (different coverage areas, mobility states, signal conditions) through a single unified mechanism, reducing overall system complexity compared to scenario-specific approaches.
Data Source
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AI summary
Methods to enhance the coverage of NR systems for coverage-limited wireless devices are disclosed. A serving base station may configure a coverage-limited UE with parameters for the UE to operate in a coverage enhancement mode through RRC signaling, DCI, or RAR grant. The UE may use the configuration parameters to determine whether to enter into the coverage enhancement mode when connecting and communicating with the serving base station. The configuration parameters may configure the UE to exploit both time diversity and frequency diversity to extend and enhance coverage when receiving the PDSCH and PDCCH channels, when transmitting the PUSCH and PUCCH channel, and when transmitting PUSCH Msg3 during random access. Advantageously, the base station may flexibly and dynamically configure the UE with coverage enhancement parameters to extend the coverage of the UE using time diversity and frequency diversity gains as the UE moves around.