Priority-Based RACH Slot Allocation for PS-LTE and LTE-M Collision Resolution
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Solution Overview
Problem
Current cellular networks face challenges in managing random access channel (RACH) overload, particularly for mission-critical high-priority users in coexisting PS-LTE and LTE-M networks, leading to preamble collisions and increased access delays, which degrade system performance and fail to meet quality of service requirements.
Innovation Solution
A mission-critical user priority-based random access method that dynamically allocates RACH slots and preambles by broadcasting information through system information block 2, selecting emergency or normal slots based on the number of high-priority user equipment (UEs), and configuring preamble allocation conditions to prevent collisions and ensure priority access for mission-critical UEs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional random access methods are used in coexisting PS-LTE and LTE-M networks, then system compatibility is maintained, but preamble collisions increase and access delay increases for mission-critical users
Solution Approach 1:
The random access procedure is segmented into two distinct paths: a prioritized random access procedure for mission-critical high-priority users and a conventional procedure for other users. This segmentation allows mission-critical users to access dedicated resources without competing with regular users, thereby reducing access delay while maintaining system compatibility
Solution Approach 2:
Different quality levels are applied to different user groups within the same network. Mission-critical users receive enhanced local quality through prioritized processing, dedicated preamble groups, and adjusted access parameters, while other users continue to use standard procedures. This localized quality enhancement resolves the contradiction by improving reliability for specific users without affecting overall system operation
2Reliability
If access probability is broadcasted to prevent RACH overload, then collision probability is reduced, but access delay increases and QoS requirements are not fulfilled
Solution Approach 1:
The system dynamically adjusts access parameters based on user priority and current network conditions. Mission-critical users are assigned different access probabilities, preamble groups, and slot selections compared to regular users. This dynamic adjustment allows the system to reduce access delay for high-priority users while maintaining collision reduction benefits for the overall network
Solution Approach 2:
Access parameters such as preamble groups, slot selections, and access probabilities are changed based on user priority classification. Mission-critical users are assigned specific parameter sets that optimize their access delay, while other users use default parameters. This parameter differentiation resolves the contradiction by allowing tailored optimization for different user categories
3Reliability
If conventional RACH resource allocation is used, then network compatibility is maintained, but collision rate increases when enormous UEs attempt access simultaneously
Solution Approach 1:
The preamble resources are segmented into different groups, with specific preamble groups allocated for prioritized random access by mission-critical users. This segmentation reduces the probability of collision between mission-critical users and regular users, as they select from different preamble pools. The segmentation principle directly addresses the harmful effect of collisions while maintaining overall network compatibility
Solution Approach 2:
The network acts as an intermediary by providing differentiated resource allocation and prioritized processing for mission-critical users. Through the prioritized random access procedure, the network mediates resource conflicts between high-priority and regular users, reducing collisions for mission-critical users while maintaining fair resource distribution across the network
Data Source
AI summary
Proposed are a mission-critical user priority-based random access method and apparatus for a collision resolution in a coexisting PS-LTE and LTE-M network. The MCHP-RA method includes broadcasting information as part of a system information block (SIB) 2 in order for an eNB to allocate a random access channel (RACH) slot in a network environment in which an LTE-based public safety (PS-LTE) network and an LTE-based marine (LTE-M) network coexist, selecting an emergency slot as a next RACH slot when the number of mission-critical high priority-based user equipments (MCHP UEs) is greater than a predefined threshold and processing the MCHP UEs during a random access procedure, and selecting a normal slot as a next RACH slot when the number of MCHP UEs is smaller than a predefined threshold and processing the MCHP UEs, wherein the eNB may allocate the RACH slot based on configurations in order to prevent a preamble collision.