Two-Step Random Access Uplink Repetition for Reduced-Capability UE
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Solution Overview
Problem
Wireless communication systems face inefficiencies in handling reduced capability user equipment (UE) due to rigid uplink transmission repetition schemes, leading to increased communication failures and resource waste.
Innovation Solution
The implementation of a flexible uplink message repetition mechanism for reduced capability UE, where the UE selects random access opportunities based on a configured set of uplink data opportunities and repetition parameters, allowing for efficient transmission of preambles and uplink messages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rigid uplink transmission repetition schemes are used for reduced capability UE, then transmission reliability is improved, but resource utilization deteriorates and communication failures increase
Solution Approach 1:
The patent implements dynamic selection of random access opportunities based on repetition parameters. The UE determines a repetition parameter for the uplink message and selects a random access opportunity from a configured set that has sufficient associated uplink data opportunities. This dynamic approach allows the system to adapt the repetition scheme to actual channel conditions and UE capabilities, improving both reliability and resource utilization compared to rigid predefined schemes.
Solution Approach 2:
The patent changes the parameter of random access opportunity selection by introducing repetition parameters and associating different numbers of uplink data opportunities with different random access opportunities. The base station configures a set of random access opportunities where each has a different number of associated uplink data opportunities. The UE selects based on its repetition parameter, matching the number of repetitions to the available uplink opportunities, thereby optimizing resource usage while maintaining reliability.
2Reliability
If uplink repetition is increased for reduced capability UE, then communication success rate is improved, but resource waste increases
Solution Approach 1:
The patent applies partial action by configuring only the necessary number of uplink data opportunities associated with each random access opportunity based on the UE's repetition parameter. Instead of providing excessive uplink opportunities for all UEs, the system provides exactly what is needed - each random access opportunity is associated with a specific number of uplink data opportunities that matches the repetition requirement. This prevents resource waste while ensuring sufficient repetitions for reliable communication.
Solution Approach 2:
The UE autonomously determines its own repetition parameter and selects the appropriate random access opportunity from the configured set based on that parameter. The UE self-configures its transmission strategy without requiring explicit scheduling for each repetition, reducing signaling overhead and enabling efficient resource utilization. The system allows UEs to self-select the appropriate level of repetition based on their capabilities and channel conditions.
3Device complexity
If reduced capability UE transmit with lower power and fewer antennas, then device complexity is reduced, but transmission reliability deteriorates
Solution Approach 1:
The patent segments the uplink transmission resources by dividing the random access opportunities into different categories based on the number of associated uplink data opportunities. Each segment is tailored to specific UE repetition requirements. Reduced capability UEs can select from segments that match their capabilities, allowing them to maintain simple device architecture while achieving reliable transmission through appropriate resource selection and repetition strategies configured by the base station.
Data Source
AI summary
Methods, systems, and devices for wireless communications are described. A user equipment (UE) may receive a configuration signal configuring a set of random access opportunities over which to transmit a preamble associated with a random access procedure, each random access opportunity associated with a set of one or more uplink data opportunities. The UE may identify a repetition parameter for an uplink message. The UE may select a random access opportunity from the set of configured random access opportunities for transmitting the preamble based at least in part on the repetition parameter. The UE may transmit the preamble on the selected random access opportunity. The UE may transmit one or more repetitions of the uplink message based at least in part on the set of one or more uplink data opportunities associated with the selected random access opportunity.