PRACH Access Control Using Virtual Frames to Reduce Collisions
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Solution Overview
Problem
The existing Physical Random Access Channel (PRACH) access mechanism in LTE systems experiences increased access collisions and retransmissions as the number of user equipment (UEs) served by a base station grows, leading to access failures due to limited PRACH access serial numbers.
Innovation Solution
A PRACH access control method that introduces a virtual access frame, where each terminal transmits a PRACH preamble serial number in each subframe, and uses a predetermined mapping or formula to calculate a unique PRACH access serial number, increasing the number of available access serial numbers and reducing collision probability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the existing PRACH access mechanism is used, then the system structure remains simple, but the number of PRACH access serial numbers is limited causing access collisions to increase
Solution Approach 1:
The patent divides the PRACH access mechanism into two parts: existing preambles and new virtual access frames. By segmenting the access resources, the system expands the number of accessible serial numbers without completely redesigning the PRACH structure, thus resolving the contradiction between quantity expansion and structure simplicity.
Solution Approach 2:
The patent introduces a new dimension (virtual access frames) to the existing PRACH access mechanism. Instead of simply increasing serial numbers within the existing framework, it adds a temporal dimension through virtual frames, allowing terminals to access more serial numbers across multiple subframes while maintaining the original structure's simplicity.
2Productivity
If more terminals are allowed to access, then network coverage increases, but access collisions increase causing more retransmissions
Solution Approach 1:
The patent applies preliminary action by pre-configuring virtual access frames and their associated serial numbers before terminals attempt access. This allows terminals to select from a larger pool of pre-prepared serial numbers, distributing access attempts more evenly and reducing collisions before they occur, thus maintaining reliability while increasing productivity.
Solution Approach 2:
The system implements feedback mechanisms where the base station monitors access patterns and can dynamically adjust virtual frame configurations. This feedback loop allows the system to optimize access distribution in real-time, preventing collision hotspots and maintaining high access success rates even as the number of terminals increases.
3Adaptability or versatility
If PRACH resources are allocated to more terminals, then access capacity increases, but the number of available serial numbers per terminal decreases
Solution Approach 1:
The patent makes PRACH resources universal by introducing virtual access frames that can serve multiple terminals simultaneously. Each virtual frame contains serial numbers that can be accessed by different terminals at different times, allowing the same physical resources to provide expanded access capacity while each terminal still has access to a sufficient number of serial numbers through the virtual frame structure.
Data Source
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AI summary
Provided are a PRACH access control method, access method and device. The PRACH access control method includes: receiving a PRACH preamble serial number transmitted by a terminal in each subframe of a virtual access frame; obtaining a PRACH access serial number of the terminal based on the received PRACH preamble serial number according to a mapping, which is predetermined with the terminal, between PRACH preamble serial numbers and PRACH access serial numbers; and transmitting the obtained PRACH access serial number to the terminal.