PRACH Repetition Timing With Common Valid Access Occasions
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Solution Overview
Problem
The time period based on PRACH occasions (ROs) for PRACH repetition transmission varies with the number of preamble repetitions, necessitating a clear definition of whether the time period should be based on the number of preamble repetitions or a common value.
Innovation Solution
A method for transmitting and receiving PRACH based on a defined time period that includes valid PRACH occasions, where the time period is determined such that at least one set can be defined for all configured numbers of preamble repetitions, using an association pattern period to map SS/PBCH block indices, allowing flexibility in configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the time period is defined based on the number of preamble repetitions, then the PRACH transmission can be accurately scheduled for each repetition number, but the implementation complexity and signaling overhead increase
Solution Approach 1:
The patent applies universality by defining a common time period that works for all configured numbers of preamble repetitions (2, 4, or 8). Instead of having separate time period definitions for each repetition number, a single time period configuration is used that can accommodate any repetition number through the association pattern mechanism, thereby reducing implementation complexity while maintaining scheduling accuracy
Solution Approach 2:
The patent changes the parameter approach from having multiple time period values (one for each repetition number) to a single time period parameter that works universally. The association pattern period and SS/PBCH block index mapping are adjusted based on the actual repetition number needed, allowing flexibility without increasing the number of configured parameters
2Reliability
If separate time periods are configured for each preamble repetition number, then precise control is achieved, but the signaling overhead increases
Solution Approach 1:
The patent reduces signaling overhead by using a universal time period configuration that serves all preamble repetition numbers. The base station signals only one time period value along with association pattern parameters, and the UE derives the appropriate PRACH occasions based on the configured repetition number, eliminating the need to signal separate time periods for each repetition number
Solution Approach 2:
The patent extracts the repetition-number-specific information from the time period configuration itself and separates it into the association pattern parameters. The common time period contains only the universal timing information, while the repetition-specific mapping is handled through the association pattern between SS/PBCH block indices and PRACH occasions, reducing the amount of signaling required
3Device complexity
If a common time period is used for all preamble repetition numbers, then implementation complexity is reduced, but the flexibility in configuring valid PRACH occasions decreases
Solution Approach 1:
The patent introduces dynamics by allowing the association pattern to be flexibly configured based on the actual repetition number needed. While the time period itself is common and fixed, the mapping between SS/PBCH block indices and PRACH occasions is dynamically adjusted according to the configured repetition number (2, 4, or 8), providing adaptability without requiring multiple fixed time period configurations
Solution Approach 2:
The patent segments the configuration into two parts: a common time period that applies to all cases, and association pattern parameters that are configured based on the specific repetition number needed. This segmentation allows the system to use a simple common time period for basic timing while maintaining flexibility through the separable association pattern configuration
Data Source
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AI summary
A method performed by a user equipment comprises transmitting a Physical Random Access CHannel (PRACH) based on a number of preamble repetitions, and receiving a Random Access Response (RAR). The PRACH is transmitted based on at least one set determined within a time period. Each set includes valid PRACH occasions based on the number of preamble repetitions. The time period is defined such that the at least one set can be determined within the time period for all configured number related to the number of preamble repetitions.