PRACH Slot Configuration for 480/960 kHz Subcarrier Spacing
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Solution Overview
Problem
The existing 3GPP Rel-15/16 specifications do not provide clear guidelines for PRACH configurations supporting subcarrier spacings beyond 120 kHz, such as 480 kHz and 960 kHz, which are necessary for extending NR operations beyond 52.6 GHz.
Innovation Solution
A low-complexity reinterpretation of the existing PRACH configuration tables for FR2, originally designed for 60 kHz or 120 kHz SCS, is applied to support 480/960 kHz by modifying the allocation rules for PRACH slots within a 60 kHz slot or redefining the reference SCS, without a complete redesign.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If existing PRACH configuration tables for FR2 (designed for 60 kHz or 120 kHz SCS) are reused for 480/960 kHz, then device complexity is reduced, but configuration accuracy and reliability deteriorate due to lack of clear guidelines
Solution Approach 1:
The patent applies parameter changes by modifying the interpretation of existing configuration table parameters to support higher SCS. Specifically, the slot duration and PRACH occasion timing parameters are adjusted based on the ratio between the target SCS (480/960 kHz) and the reference SCS (60/120 kHz), allowing the same table structure to function correctly for different numerologies without requiring complete table redesign.
Solution Approach 2:
The patent introduces dynamic interpretation rules that allow the configuration table to adapt to different SCS values. The configuration parameters are no longer fixed but are dynamically scaled based on the operating SCS, enabling the same static table structure to serve multiple dynamic numerologies (60 kHz, 120 kHz, 480 kHz, 960 kHz).
2Reliability
If a complete redesign of PRACH configuration tables is performed to support 480/960 kHz, then configuration reliability is improved, but device complexity and implementation effort increase
Solution Approach 1:
The patent achieves universality by designing a single configuration table that can serve multiple purposes across different SCS values. Through reinterpretation rules, the same table structure is made multi-functional, supporting 60 kHz, 120 kHz, 480 kHz, and 960 kHz without requiring separate tables for each numerology, thus avoiding complete redesign while ensuring reliability.
Solution Approach 2:
The patent introduces intermediary reinterpretation rules as a mediator between the existing configuration table and the new high-SCS requirements. These rules act as a translation layer that maps the existing table parameters to the new SCS context, enabling reliable configuration without direct modification of the table structure itself.
3Productivity
If PRACH slots are allocated within a 60 kHz slot for higher SCS operations, then time efficiency is improved, but slot allocation accuracy deteriorates due to scaling factors
Solution Approach 1:
The patent applies segmentation by dividing the 60 kHz reference slot into multiple smaller time units corresponding to the higher SCS. For 480 kHz SCS, one 60 kHz slot contains eight 480 kHz slots, and for 960 kHz SCS, it contains sixteen 960 kHz slots. This segmentation allows precise allocation of PRACH occasions at the finer time granularity while maintaining the coarser reference structure.
Solution Approach 2:
The patent resolves the precision issue by adding a scaling dimension to the time domain configuration. The slot allocation is performed in two dimensions: the coarse 60 kHz slot structure provides the framework, while the fine-grained 480/960 kHz slots within each 60 kHz slot provide the precise timing. This dimensional separation allows both efficiency and precision to coexist.
Data Source
AI summary
A method, system and apparatus are disclosed. According to some embodiments, a wireless device is provided. The wireless device includes processing circuitry configured to and/or that operates to: select at least one slot from a plurality of slots that correspond to a first subcarrier spacing, SCS, greater than 120 kHz where each of the at least one slot includes at least physical random access channel, PRACH, occasion, and cause PRACH signaling based on the at least one slot.