IoT Random Access Method Using Dynamic Coverage Class Adjustment
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Solution Overview
Problem
In cellular-based IoT systems, particularly Narrowband-IoT (NB-IoT), the existing random access process is inefficient due to increased operation time and energy consumption when a terminal fails to receive a random access response or contention resolution, requiring repeated preamble transmissions across different coverage classes, which prolongs the random access procedure.
Innovation Solution
The method involves sequentially using preamble resources during the random access process by considering performance characteristics of subcarrier spacing and multi-tone configurations within each coverage class, allowing terminals to change the subcarrier spacing and multi-tone configuration when necessary to optimize resource selection and reduce the number of retransmissions, thereby minimizing the change in coverage class and operation time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If terminals repeatedly transmit preambles across different coverage classes when random access fails, then coverage reliability is improved, but operation time and energy consumption increase
Solution Approach 1:
The patent dynamically adjusts the coverage class based on terminal performance and channel conditions. Instead of statically assigning terminals to fixed coverage classes, the system allows terminals to transition between coverage classes (e.g., from enhanced coverage class to normal coverage class) as their random access success rate improves, thereby reducing operation time while maintaining reliability.
Solution Approach 2:
The patent changes the coverage class parameter based on terminal performance metrics such as random access success rate. When a terminal achieves a certain number of successful random accesses, its coverage class is upgraded, which modifies transmission parameters like subcarrier spacing and multi-tone configuration, leading to faster access times while preserving connection reliability.
2Adaptability or versatility
If terminals use multiple subcarrier spacing and multi-tone configurations, then resource selection flexibility is improved, but device complexity increases
Solution Approach 1:
The patent segments the random access resources into different coverage classes, each with specific subcarrier spacing and multi-tone configuration settings. Terminals are guided to select from predefined configurations appropriate for their current coverage class, which simplifies the selection process while maintaining flexibility across different channel conditions.
Solution Approach 2:
The patent pre-configures multiple subcarrier spacing and multi-tone configuration options for each coverage class before random access attempts. Terminals can directly select from these pre-defined configurations based on their assigned coverage class, eliminating the need for complex real-time optimization and reducing device complexity while preserving adaptability.
3Productivity
If terminals transmit small data packets, then data transmission efficiency is improved, but random access delay increases due to repeated failures
Solution Approach 1:
The patent implements dynamic coverage class adjustment that responds to terminal performance. Terminals experiencing random access failures remain in enhanced coverage classes with more robust configurations, while successful terminals transition to normal coverage classes with faster access parameters. This dynamic adjustment reduces random access delay for small data transmissions while maintaining transmission efficiency.
Solution Approach 2:
The patent enables terminals to self-adjust their coverage class based on their own performance metrics such as random access success rate. This self-service mechanism allows terminals to automatically optimize their access parameters without network intervention, reducing delay for small data transmissions while maintaining efficiency through performance-based configuration selection.
Data Source
AI summary
Provided is random access method, performed by terminal for uplink data transmission during random access process between cellular based machine communication terminal and base station. The method includes performing random access process between cellular based machine communication terminal and base station, and the random access process includes selecting random access resource by considering coverage level and whether to support multi-tone transmission or not. Terminal can perform efficient random access process in response to coverage level, subcarrier spacing configuration, multi-tone configuration when machine communication terminal or machine communication device which operates in cellular based IoT system perform random access, number of repetition may be increased, when coverage level is changed, by minimizing the change in coverage level, and operation time of the terminal, due to standing by up to PRACH resource corresponding to the coverage level, may be reduced to reduce energy consumption and to enhance delay time performance.