RACH Resource Identification via Bitmap in 5G NR
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In the 5G NR wireless communication system, indicating available RACH resources to user apparatuses for initial access is inefficient due to high signaling overhead, as it requires specifying positions in both time and frequency domains, preamble indexes, and associated SS blocks.
Innovation Solution
A user apparatus is provided with a reception unit to receive TDD-UL-DL-Configuration indicating UL, DL, or Unknown areas, a RACH configuration table for resource allocation, and a control unit to identify available RACH resources by excluding unavailable resources, allowing efficient transmission of preambles using identified resources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If the entire information for specifying RACH resources is indicated, then the user apparatus can identify available resources, but the signaling overhead increases
Solution Approach 1:
The patent extracts only the necessary information for RACH resource identification by using a bitmap structure where each bit corresponds to a time slot's availability status. Instead of transmitting complete RACH configuration details for all time slots, the system transmits a compact bitmap indicating only which time slots contain available RACH resources, significantly reducing signaling overhead while maintaining sufficient information for user apparatus to identify valid resources.
Solution Approach 2:
The patent changes the parameter representation from detailed textual or numerical specifications to a compact binary bitmap format. This parameter transformation allows the system to convey availability information efficiently using minimal bits, converting what would otherwise be extensive configuration data into a concise indicator that reduces signaling overhead without losing identification capability.
2Measurement precision
If detailed RACH resource information is transmitted, then resource allocation is precise, but the signaling overhead increases
Solution Approach 1:
The patent segments the RACH resource information into two parts: a bitmap indicating which time slots have available resources, and implicit time slot indexing. This segmentation allows the system to transmit only the essential availability pattern rather than detailed resource specifications for each slot, reducing signaling complexity while maintaining precise allocation identification through the combination of bitmap positions and time slot indices.
Data Source
AI summary
A terminal includes: a receiver configured to receive, from a base station apparatus, first configuration information indicating an Uplink, a Downlink, or a Flexible area in a radio frame, and second configuration information indicating a random access channel (RACH) resource allocation in the radio frame in a time domain; a processor configured to identify an available RACH resource in the radio frame based on the first configuration information and the second configuration information; and a transmitter configured to transmit a preamble to the base station apparatus using the identified available RACH resource.