PRACH Repetition for Uplink Coverage in 5G Random Access
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Solution Overview
Problem
Current wireless communication systems face challenges in providing adequate uplink coverage, particularly in 5G/NR networks, due to increased data traffic and the need for improved radio interface efficiency and coverage, especially in scenarios requiring multiple PRACH transmissions within a single random access attempt.
Innovation Solution
The implementation of PRACH repetition mechanisms in user equipment (UE) and base stations, which involve selecting appropriate bandwidth parts, determining the number of Msg1 repetitions, and configuring random access procedures to enhance uplink coverage by optimizing UL carrier selection, BWP selection, and random access resource configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple PRACH transmissions are performed within a single random access attempt to enhance uplink coverage, then the reliability of random access procedures is improved, but the device complexity and configuration overhead increase
Solution Approach 1:
The patent segments the random access procedure by introducing separate configuration parameters for different message types (Msg1, Msg3, MsgA) and different repetition scenarios. This allows the system to enable PRACH repetitions selectively for specific message types and scenarios without requiring complete reconfiguration of the entire random access procedure, thereby improving reliability while managing complexity through modular configuration.
Solution Approach 2:
The patent introduces new configurable parameters (msg1-RepetitionNumber, msg3-RepetitionNumber, msgA-RepetitionNumber, prach-RepetitionFactor) that allow dynamic adjustment of repetition counts based on coverage requirements. These parameter changes enable the system to adapt the level of repetition (and thus reliability) to specific deployment scenarios without hardcoding complex behavior, balancing reliability improvement with configuration manageability.
2Area of stationary object
If PRACH repetition mechanisms are implemented to support challenging coverage areas, then the uplink coverage is enhanced, but the use of energy and transmission resources increase
Solution Approach 1:
The patent implements dynamic repetition behavior where the actual number of repetitions performed can be adjusted based on whether the transmission is successful. The system allows for configurable repetition numbers but enables early termination when coverage is achieved, making the energy consumption adaptive rather than fixed. This dynamic approach allows the system to expand coverage to challenging areas while avoiding unnecessary energy expenditure when fewer repetitions suffice.
Solution Approach 2:
The patent introduces configurable parameters (prach-RepetitionFactor, msg1-RepetitionNumber, etc.) that allow the network to optimize the balance between coverage extension and energy consumption based on specific deployment scenarios. By allowing flexible parameter adjustment, the system can enable higher repetition counts only where and when needed for coverage extension, rather than applying maximum repetitions universally, thus managing energy usage more efficiently.
3Adaptability or versatility
If separate configuration parameters are introduced for different message types and repetition scenarios, then the adaptability of the random access procedure is improved, but the configuration overhead and parameter management complexity increase
Solution Approach 1:
The patent creates a universal configuration framework where a set of parameters (msg1-RepetitionNumber, msg3-RepetitionNumber, msgA-RepetitionNumber, prach-RepetitionFactor) can serve multiple functions across different random access scenarios. These parameters work together in a coordinated manner, allowing the same configuration mechanism to handle Contention-Based Random Access, Contention-Free Random Access, and different message types uniformly, thereby achieving high adaptability without proportionally increasing overhead.
Solution Approach 2:
The patent performs preliminary configuration by establishing the repetition parameters in advance through RRC signaling before the actual random access procedure occurs. This allows the UE to be pre-configured with the necessary repetition behavior for different message types and scenarios, eliminating the need for dynamic negotiation during the random access procedure itself. The configuration overhead is paid upfront rather than repeatedly, improving adaptability while managing information overhead efficiently.
Data Source
AI summary
A user equipment (UE) includes a transceiver configured to receive one or more random access (RA) configurations for a cell, and receive a contention free random access (CFRA) configuration related to a RA procedure. The UE further includes a processor operatively coupled to the transceiver. The processor is configured to select a bandwidth part (BWP) of the cell for performing the RA procedure, select a four step RA as a type for the RA procedure, determine whether the CFRA configuration for the RA procedure includes a parameter indicating a number of message 1 (Msg1) repetitions, and perform the RA procedure in the cell according to a result of the determination.