PRACH Occasion Allocation Across Sub-Bands Under LBT Constraints
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Solution Overview
Problem
Existing communication technologies lack efficient and reliable methods for establishing a random access channel (RACH) procedure in 5G New Radio (NR) systems operating in unlicensed bands, where listen before talk (LBT) procedures reduce transmission opportunities and degrade efficiency.
Innovation Solution
The solution involves configuring random access channel (RACH) procedures per frequency region, allowing for multiple LBT attempts across different frequency sub-bands to enhance transmission opportunities, and distributing ROs across multiple frequency regions to ensure successful communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LBT procedure is performed in unlicensed bands, then channel access compliance is ensured, but transmission opportunities are reduced and efficiency is degraded
Solution Approach 1:
The patent segments the frequency band into multiple frequency regions, each with its own LBT procedure and RO candidates. This allows the system to perform LBT independently in each region, so that if one region is occupied, other regions may still be available for transmission, thereby maintaining channel access compliance while improving overall transmission efficiency
Solution Approach 2:
The patent introduces frequency region diversity as an additional dimension for RACH procedure establishment. By distributing RO candidates across multiple frequency regions rather than relying on a single frequency channel, the system creates multiple independent paths for successful transmission, effectively adding a spatial-frequency dimension to overcome LBT blocking
2Reliability
If multiple RO candidates are distributed across multiple frequency regions, then successful RACH transmission probability is improved, but system complexity increases
Solution Approach 1:
The patent divides the PRACH configuration into multiple frequency region-specific configurations, each with its own set of RO candidates. The terminal device is configured to perform LBT procedures and select RO candidates independently in each frequency region, which systematically manages the complexity by organizing it into manageable segmented units rather than a monolithic complex system
Solution Approach 2:
The patent applies different PRACH configuration parameters locally to each frequency region, allowing optimal configuration for each region's characteristics. Each frequency region can have tailored RO candidate sets and LBT parameters, enabling the system to adapt to local frequency conditions while maintaining overall coordination through base station control
Data Source
AI summary
The present disclosure provides apparatuses and methods for establishing a random access. The apparatuses include a terminal which comprises circuitry which, in operation, generates a first random access preamble; and a transmitter which, in operation, transmits the first random access preamble to a base station on a first physical random access channel (PRACH) occasion (RO) among a plurality of RO candidates, the plurality of RO candidates being determined based on PRACH configuration information received from the base station, wherein the first RO is assigned within a first frequency region, the first frequency region being equal to a first sub-band in which a listen before talk (LBT) procedure is performed at the terminal.