Uplink Control Channel Resource Configuration for Shared Spectrum
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Solution Overview
Problem
Current wireless communication systems, particularly in 5G and New Radio (NR) systems, face challenges in efficiently configuring uplink control channel resources for repeated transmissions in shared radio frequency spectrum, leading to suboptimal performance and resource utilization.
Innovation Solution
The proposed solution involves configuring user equipment (UE) with specific time and frequency resources for repeated Physical Uplink Control Channel (PUCCH) transmissions, including a set of transmission time intervals (TTIs) and a maximum number of retransmissions, allowing for improved resource allocation and listen-before-talk (LBT) procedures to contend for the medium.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If repeated PUCCH transmissions are performed in shared spectrum, then reliability of uplink control information is improved, but resource waste occurs due to unnecessary repetitions
Solution Approach 1:
The base station monitors the shared spectrum channel and provides feedback to the UE about channel availability and interference conditions. Based on this feedback, the base station dynamically controls whether the UE should transmit repeated PUCCH transmissions or terminate early, ensuring reliable delivery while avoiding resource waste when channel conditions are already favorable.
Solution Approach 2:
The system transitions from static repeated transmission configuration to dynamic control where the base station adjusts the number of repetitions in real-time based on channel conditions. The base station can signal the UE to terminate repetitions early when reliability is achieved, making the transmission pattern adaptive rather than fixed.
2Reliability
If multiple TTIs are allocated for PUCCH repetitions, then signal-to-interference-plus-noise ratio is improved through redundancy, but power consumption increases
Solution Approach 1:
The base station provides feedback about channel quality and interference levels to the UE. Based on this feedback, the base station determines the optimal number of repetitions needed and signals the UE accordingly, allowing the UE to conserve power by transmitting fewer repetitions when channel conditions are good while maintaining SINR through adequate repetitions when conditions are poor.
Solution Approach 2:
The system dynamically changes the transmission parameter (number of repetitions) based on channel conditions. Instead of fixed multiple TTI allocations, the base station adjusts the repetition count parameter in real-time, optimizing the balance between achieving sufficient SINR through redundancy and minimizing power consumption.
3Productivity
If listen-before-talk procedures are performed before each PUCCH transmission, then spectral efficiency is improved by avoiding collisions, but time delay increases
Solution Approach 1:
The base station performs preliminary actions by monitoring the channel and predicting interference conditions before the UE needs to transmit. The base station can pre-signal the UE about favorable transmission opportunities, allowing the UE to skip LBT procedures in certain cases and transmit directly, reducing time delay while the base station maintains spectral efficiency through its advance channel assessment.
Data Source
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AI summary
A base station may access a channel following a successful channel access procedure. The base station may transmit an indication of a resource allocation to a user equipment (UE). The resource allocation may include an allocation of resources for subsequent communications between the base station and the UE, for example, defining a set of transmission time intervals (TTIs) during which the UE may transmit repetitions of uplink control information. The UE may also perform a channel access procedure to access the channel. The UE may transmit repetitions of the uplink control information using the set of TTIs according to the resource configuration. In some cases, the UE may stop transmitting uplink control information repetitions after a maximum number repetitions also according to the resource configuration. The base station may then receive and combine the uplink control information.