NR Initial Access RACH Allocation Across Multiple Configuration Tables
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Solution Overview
Problem
The limited number of indices in the RACH configuration table in NR makes it difficult to efficiently notify user equipment of available RACH resources during initial access, particularly in high-frequency bands where beam forming is applied.
Innovation Solution
The solution involves defining a new RACH configuration table for non-standalone environments, allowing for flexible allocation of RACH resources by using additional indices and signaling, and associating SS blocks with RACH resources to enhance resource notification efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If the existing RACH configuration table with limited indices is used, then the system maintains simplicity in configuration management, but it becomes impossible to efficiently notify user equipment of available RACH resources corresponding to the number of and allocation of SS blocks in NR
Solution Approach 1:
The RACH configuration is segmented into multiple separate tables (first RACH configuration table and second RACH configuration table) instead of using a single comprehensive table. Each table contains a subset of RACH resource configurations, allowing the system to notify user equipment of available resources across multiple organized tables rather than requiring one excessively large table with limited indices
Solution Approach 2:
The patent introduces a new dimension to the configuration structure by organizing RACH configurations across multiple tables with different purposes (broadcast information vs. RRC signaling). This multi-dimensional organization allows efficient notification of RACH resources corresponding to SS blocks without requiring an excessively large single table, resolving the contradiction between information completeness and structural simplicity
2Adaptability or versatility
If multiple RACH configuration tables are introduced to notify user equipment of available RACH resources, then the flexibility and accuracy of RACH resource allocation is improved, but the complexity of configuration management increases
Solution Approach 1:
The patent creates a universal multi-table configuration system where the first RACH configuration table serves broadcast information and the second serves RRC signaling. Each table has its own index structure and can be independently managed, allowing flexible and accurate RACH resource allocation while maintaining manageable complexity through clear separation of functions across tables
3Loss of information
If the RACH configuration table indices are increased to cover all SS block allocations, then complete RACH resource notification is achieved, but the difficulty of detecting and measuring the configuration increases
Solution Approach 1:
By segmenting the RACH configuration into multiple tables with smaller, more manageable index sets, the patent reduces the difficulty of detecting and measuring configurations. User equipment can efficiently search and identify RACH resources within each smaller table rather than searching through one large table with excessive indices, while still achieving complete notification of available RACH resources across all tables
Data Source
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AI summary
Disclosed is user equipment for communicating with a base station via a radio frame. The user equipment includes a receiving unit that receives an index relating to a RACH configuration table indicating allocation of RACH resources in the radio frame from the base station; a control unit that identifies an available RACH resource based on a plurality of different RACH configuration tables and the index; and a transmitting unit that transmits a preamble to the base station using the identified available RACH resource.