PRACH Random Access Across LBT Frequency Regions
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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 are required, leading to reduced transmission opportunities due to LBT failures.
Innovation Solution
The solution involves configuring random access channel (RACH) procedures per frequency region, allowing for multiple LBT attempts across different frequency sub-bands, thereby increasing transmission opportunities by distributing ROs across multiple frequency regions and utilizing them for either single or multiple RACH procedures.
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 due to LBT failures
Solution Approach 1:
The bandwidth is divided into multiple frequency regions, each with its own RO candidates. This segmentation allows the terminal to perform LBT independently in each frequency region and select successful regions for transmission, thereby maintaining compliance while increasing overall transmission opportunities.
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, the system creates multiple parallel paths for successful transmission.
2Device complexity
If ROs are concentrated in a single frequency region, then configuration simplicity is maintained, but RACH procedure reliability is reduced due to LBT failures
Solution Approach 1:
The patent segments the frequency spectrum into multiple regions and distributes RO candidates across these regions. Each frequency region can be configured with its own set of RO candidates, allowing the system to maintain manageable configuration complexity while improving reliability through frequency diversity.
Solution Approach 2:
The patent changes the parameter of frequency distribution for RO candidates, transitioning from a single-frequency concentration to multi-frequency distribution. This parameter change enables the system to achieve both configuration simplicity and improved reliability by allowing flexible allocation across frequency regions.
3Productivity
If multiple RO candidates are distributed across multiple frequency regions, then transmission opportunities are increased, but configuration complexity increases
Solution Approach 1:
The patent organizes the multiple RO candidates into segmented frequency regions, where each region can be independently configured and managed. This segmentation approach allows the system to handle multiple RO candidates in a structured manner, increasing transmission opportunities while keeping configuration complexity manageable through modular organization.
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.