LTE Random Access Congestion Control via Sequence Number Extension
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Solution Overview
Problem
The increasing number of connected smartphones in mobile communication systems leads to cell congestion, particularly on the random access channel, due to the limitations of layer 2 sequence number length, which restricts the achievable data rate in LTE and LTE-Advanced systems.
Innovation Solution
A method and apparatus for congestion control in User Equipment (UE) in connected states, involving the detection of random access triggers, checking trigger types, and applying congestion control measures, such as broadcasting threshold values for determining uplink transmission in LTE systems, and extending the sequence number length to enhance data rate capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If carrier aggregation is implemented to increase data rate, then peak data rate increases in proportion to the number of aggregated carriers, but the intrinsic problem of layer 2 short sequence number length restricts the achievable data rate
Solution Approach 1:
The patent extends the sequence number length in the PDCP layer from the conventional limited length to a longer length (e.g., 18 bits or more), fundamentally changing the parameter of sequence number capacity. This allows the system to support higher data rates achieved through carrier aggregation without being constrained by the original sequence number length limitation, thereby resolving the contradiction between increased productivity and device complexity.
2Adaptability or versatility
If the number of terminals in connected state increases to provide always-on services, then service availability improves, but the probability of congestion on the random access channel increases
Solution Approach 1:
The patent introduces a barring mechanism that performs preliminary control on random access attempts by terminals in connected state. The network can configure barring parameters (barring factor, barring time) that prevent terminals from immediately attempting random access after certain events, thereby proactively preventing congestion before it occurs while still allowing always-on services to function.
Solution Approach 2:
The patent implements a feedback-based congestion control mechanism where the network monitors random access channel congestion status and dynamically adjusts barring parameters. When congestion is detected, the network configures appropriate barring factors and times to control terminal access behavior, creating a closed-loop feedback system that balances service availability with congestion prevention.
Data Source
AI summary
The present specification relates to a communication method and a communication device, and a random access method of a user equipment (UE), according to one embodiment of the present specification, comprises the steps of: sensing a random access trigger in a connected state; determining the type of the random access trigger when the random access trigger is sensed; and performing congestion control if the type of the random access trigger is a preset type.