PUCCH Repetition for Random Access Coverage
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Solution Overview
Problem
Current wireless communication systems, particularly in 5G NR, face challenges in providing coverage enhancements for Physical Uplink Control Channel (PUCCH) transmissions during random access procedures, especially when these transmissions are not scheduled using dedicated PUCCH resources, leading to reduced reliability and coverage for NR-Light UEs and high-frequency band communications.
Innovation Solution
The proposed solution involves determining a repetition level for PUCCH transmissions prior to receiving dedicated PUCCH resource configuration, allowing for intra-slot or inter-slot repetition and frequency hopping, and applying cyclic shifts to enhance coverage, even for PUCCH transmissions without dedicated resources, by using system information or DCI messages to signal the repetition level and type of frequency hopping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If PUCCH transmissions are performed without dedicated PUCCH resources during random access procedures, then device complexity is reduced and initial access is simplified, but coverage and reliability deteriorate
Solution Approach 1:
The UE autonomously determines PUCCH transmission parameters including repetition level and frequency hopping based on pre-configured rules and received downlink assignments, without requiring dedicated PUCCH resource configuration from the network. This self-service mechanism simplifies the system while maintaining reliable transmission through structured autonomous decision-making
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting PUCCH transmission parameters such as repetition level (number of repetitions), frequency hopping patterns, and cyclic shifts based on the received downlink assignment and channel conditions. These parameter adjustments enable adaptive transmission reliability without dedicated resource configuration
2Area of stationary object
If PUCCH repetition is applied to extend coverage, then coverage area increases, but transmission time and latency increase
Solution Approach 1:
The patent implements dynamic repetition level selection where the number of PUCCH repetitions is adjusted based on received signal quality, downlink assignment type, and channel conditions. This dynamic approach allows the system to use more repetitions for coverage extension when needed while minimizing repetitions to reduce latency when channel conditions are good
Solution Approach 2:
The PUCCH transmission is segmented into multiple repetitions distributed across different time slots and frequency resources. This segmentation allows the transmission to be spread out, improving coverage through diversity while managing overall transmission time through optimized scheduling of individual repetition segments
3Reliability
If frequency hopping is applied to PUCCH transmissions, then robustness against frequency-selective fading improves, but spectral efficiency decreases
Solution Approach 1:
The patent applies partial frequency hopping where only certain PUCCH repetitions perform frequency hopping while others remain on the initial frequency. This partial action provides frequency diversity protection against fading for critical repetitions while maintaining spectral efficiency by avoiding unnecessary frequency transitions in all repetitions
Data Source
AI summary
Methods, systems, and devices for wireless communication are described. A wireless device may determine a Physical Uplink Control Channel (PUCCH) resource for a PUCCH transmission prior to receiving a dedicated PUCCH resource configuration, determining a repetition level for the PUCCH transmission, and transmit the PUCCH transmission, on at least the PUCCH resource, according to the repetition level. A base station may transmit, to a user equipment (UE), information scheduling a Physical Uplink Control Channel (PUCCH) transmission on a PUCCH resource prior to configuring dedicated PUCCH resources for the UE, determine a repetition level for the PUCCH transmission, transmit, to the UE, an indication of the repetition level, and receive, according to the repetition level, a first repetition of the PUCCH transmission on the PUCCH resource and other repetitions of the PUCCH transmission.