Timer-Based Queue State Estimation for LTE Resource Allocation
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Solution Overview
Problem
In LTE mobile networks, eNodeBs may erroneously infer a user equipment (UE) queue state as zero, leading to delays and inefficient resource allocation due to missed buffer status reports, causing poor user experience and resource wastage.
Innovation Solution
A timer-based scheme is implemented where a BSR grant timer is started when the eNodeB estimates a UE queue state as zero, and a control message is sent to the UE upon timer expiry to ensure a periodic buffer status report is generated, allowing the eNodeB to accurately determine the queue state and prioritize resource allocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the eNodeB estimates the UE queue state as zero based on previously received buffer status reports, then resource allocation is reduced and network efficiency is improved, but the queue state estimation becomes inaccurate and causes delays
Solution Approach 1:
The eNodeB sends a control message granting uplink resources to the UE in advance, before receiving the buffer status report, to ensure the UE can transmit its current buffer status. This preliminary resource allocation prevents the eNodeB from making inaccurate zero-queue assumptions and resolves the contradiction by ensuring accurate queue state information is obtained while maintaining efficient resource management.
2Measurement precision
If the eNodeB waits for buffer status reports from the UE to determine queue state, then accurate queue state estimation is achieved, but end-to-end delays increase and user experience deteriorates
Solution Approach 1:
The eNodeB proactively sends a control message granting uplink resources to the UE before the buffer status report is received, ensuring the UE can immediately transmit its queue state information without waiting for resource allocation. This eliminates unnecessary delays while ensuring accurate queue state estimation is obtained.
Solution Approach 2:
The system establishes a feedback mechanism where the eNodeB sends control messages to trigger buffer status reports from the UE. This active feedback loop ensures the eNodeB receives accurate queue state information in a timely manner, resolving the contradiction between obtaining accurate measurements and minimizing delays.
3Productivity
If the eNodeB does not send control messages to UEs with estimated zero queue state, then resource allocation is optimized, but deadlocks occur and resource utilization decreases
Solution Approach 1:
The eNodeB sends control messages to a subset of UEs - specifically those with estimated zero queue state - to request buffer status reports. This partial action approach maintains resource allocation efficiency for the majority of UEs while ensuring reliability for those that may have non-zero queue states, resolving the contradiction between optimization and reliability.
Data Source
AI summary
Embodiments include starting a first timer if a queue state associated with a user equipment (UE) is estimated to equal zero bytes of data and if a last buffer status report received from the UE indicated the queue state to be greater than zero bytes of data, sending a control message granting uplink resources to the UE if the first timer expires, and determining the queue state associated with the UE based, at least in part, on a response to the control message. In specific embodiments the first timer expires if neither a scheduling request nor a buffer status report is received during a first timer interval after the first timer is started. Further embodiments include stopping the first timer if a scheduling request or a buffer status report is received before the first timer expires.