MTC Device Access Control via RACH Segmentation
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Solution Overview
Problem
The existing random access procedures in cellular networks, particularly for Machine Type Communication (MTC) devices, lead to uncontrollable peaks in Random Access Channel (RACH) intensity due to simultaneous access attempts, resulting in increased collision probabilities and degraded user experience for non-MTC UEs.
Innovation Solution
A method where the network controls MTC device access by instructing them to spread their transmissions over time using Group Identifiers and temporary identifiers, reducing the likelihood of simultaneous access and mitigating RACH intensity peaks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If MTC devices are programmed to send data at specific times (e.g., late at night when network activity is low), then data transmission efficiency is improved, but RACH intensity peaks occur causing increased collision probability
Solution Approach 1:
The invention segments the MTC device population into different groups using Group Identifiers (GIDs). Each group is assigned specific RACH resources (time slots, frequency resources, or preamble sequences), thereby distributing the concentrated access attempts across multiple segments and reducing peak RACH intensity and collision probability.
Solution Approach 2:
The network dynamically configures RACH resources and Group Identifiers for MTC devices based on observed RACH intensity patterns and network conditions. This dynamic adjustment allows the system to adapt to varying traffic loads and prevent recurring RACH peaks by modifying resource allocation in response to measured performance metrics.
2Manufacturing precision
If the number of Access Classes is increased to provide special access classes for MTC devices, then access control precision is improved, but UE SIM adjustment complexity and communication overheads increase significantly
Solution Approach 1:
Instead of modifying the fundamental Access Class parameter stored in UE SIM, the invention introduces a new parameter - Group Identifier (GID) - that can be configured and updated without changing the core SIM structure. This allows flexible access control for MTC devices while maintaining compatibility with existing UE architectures and avoiding significant SIM adjustments.
3Reliability
If Access Class Barring is used to prevent a certain fraction of UEs from accessing the network, then network congestion is reduced, but user experience for non-MTC UEs becomes extremely degraded
Solution Approach 1:
The invention applies access control measures specifically to MTC devices through Group Identifiers and dedicated RACH resources, rather than implementing blanket Access Class Barring that affects all UEs equally. This localized approach allows the network to manage MTC-specific congestion while leaving normal UE access patterns unchanged, thereby maintaining good user experience for non-MTC devices.
4Device complexity
If MTC devices use the same RACH resources as other UEs, then resource allocation simplicity is maintained, but RACH intensity peaks from simultaneous MTC access attempts overwhelm the resources
Solution Approach 1:
The invention segments RACH resources into different pools associated with different Group Identifiers. MTC devices are assigned to specific groups and use only the RACH resources designated for their group, preventing simultaneous access attempts from all MTC devices from overwhelming a single resource pool while maintaining relatively simple resource allocation through group-based assignment.
Data Source
AI summary
Controlling access by a User Equipment (UE) to a cellular network may be effected by: receiving an instruction at the UE from a base station of the cellular network regarding transmission by the UE over a Random Access Channel (RACH) of the cellular network; and controlling when transmissions are made from the UE over the RACH, on the basis of the received instruction. In some cases, a transmission over the RACH may be made in response to the received instruction, which gives permission for the UE to transmit if it has data to send. In other cases, the instruction specifies a Group Identifier, which is compared with a Group Identifier specific to the UE and transmission over the RACH may be avoided based on the comparison. In particular, the UE may be a Machine Type Communication device.