Wireless Communication Node Adaptive Backoff for PRACH Load Balancing
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Solution Overview
Problem
Existing random access backoff mechanisms in wireless communication systems, particularly for PRACH, fail to effectively address cell overload issues during PRACH repetition, leading to increased latency and difficulty in load balancing.
Innovation Solution
A self-adaptive random access backoff mechanism that adjusts the execution time for selecting a second random access resource group based on a first backoff parameter value, allowing for PRACH repetition without waiting for a fixed backoff time, thereby addressing cell overload and reducing latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed backoff time mechanism is used to solve cell overload, then cell load balancing is improved, but random access latency increases
Solution Approach 1:
The patent applies dynamics by transitioning from a fixed backoff time mechanism to a dynamic backoff mechanism. The backoff time is no longer fixed but is determined based on the backoff indicator value received in the random access response. This allows the system to adaptively adjust the backoff time according to actual network conditions, thereby reducing unnecessary latency while maintaining cell load balancing capabilities.
Solution Approach 2:
The patent changes the parameter of backoff time from a fixed value to a variable value that depends on the backoff indicator. By introducing this parameter change, the system can flexibly adjust the waiting time based on network congestion levels, resolving the contradiction between ensuring cell load balancing and minimizing random access latency.
2Reliability
If PRACH repetition is performed to enhance uplink coverage, then PRACH coverage is improved, but cell overload condition changes and existing backoff mechanism becomes difficult to apply
Solution Approach 1:
The patent introduces feedback by using the backoff indicator value received in the random access response to determine the backoff time. This feedback mechanism allows the system to adapt to changing network conditions caused by PRACH repetition, maintaining the effectiveness of the backoff mechanism even when uplink coverage enhancement is implemented through repetition.
Solution Approach 2:
The patent applies dynamics by making the backoff time adaptive rather than fixed. This adaptability allows the backoff mechanism to work effectively alongside PRACH repetition, as the backoff time adjusts based on actual network conditions, resolving the incompatibility between coverage enhancement and load balancing.
3Reliability
If backoff time is extended to balance cell load, then cell overload is reduced, but random access process latency increases
Solution Approach 1:
The patent changes the backoff time parameter from a fixed extended value to a variable value based on the backoff indicator. This parameter change allows the system to extend backoff time only when necessary (when the backoff indicator indicates high congestion), thereby reducing cell overload while minimizing unnecessary latency extensions.
Solution Approach 2:
The system applies self-service by automatically determining the appropriate backoff time based on the backoff indicator received from the network. This self-adjusting mechanism eliminates the need for manual configuration of extended backoff times, allowing the system to balance cell overload reduction and latency minimization automatically based on real-time network conditions.
Data Source
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AI summary
Disclosed in the present application is a method and an apparatus used in a wireless communication node. The communication node, during a first random access process, sends a preamble according to a first random access resource group; in response to sending the preamble according to the first random access resource group, receives a first MAC subPDU, wherein the first MAC subPDU indicates a first backoff parameter value; and in response to the first random access process not being completed, selects a second random access resource group, and sends the preamble according to the second random access resource group; wherein whether the execution time of the action of selecting the second random access resource group depends on the first backoff parameter value is related to the second random access resource group; the first random access resource group and the second random access resource group are both assigned to 4-step random access. The present application provides a random access backoff mechanism that self-adaptively adjusts the execution time of the performance of the random access resource selection process for uplink coverage enhancement of PRACH.