Uplink Starvation Avoidance in LTE Systems
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Solution Overview
Problem
In LTE systems, uplink (UL) starvation occurs due to limited radio resources, where high priority services dominate available bandwidth, leading to resource starvation for lower priority flows, and the WTRU centric solution faces issues with grant loss and resource allocation due to lack of mechanisms for buffer status reporting and token bucket management.
Innovation Solution
The method involves the WTRU reporting current buffer status information, including token bucket sizes and accumulation patterns, to the eNB to prevent grant loss, allowing the eNB to make informed grant allocations and avoid resource starvation by using token bucket configurations and RRC signaling for efficient resource management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the WTRU centric solution with pre-transmission traffic policing is used, then UL starvation avoidance is improved, but grant loss occurs due to lack of buffer status reporting mechanism
Solution Approach 1:
The patent introduces a feedback mechanism where the WTRU reports buffer status information to the network, enabling the network to make informed grant allocation decisions. This feedback loop prevents grant loss by ensuring the WTRU has accurate information about available resources before transmitting data, thereby resolving the contradiction between UL starvation avoidance and grant loss prevention.
Solution Approach 2:
The patent implements preliminary action by having the network configure token bucket parameters and MBR/aMBR values before the WTRU performs traffic policing. This advance configuration allows the WTRU to make accurate buffer status reports and prevents grant loss by ensuring resource constraints are known beforehand, thus maintaining both UL starvation avoidance and preventing grant loss.
2Productivity
If token bucket configuration is implemented for traffic policing, then resource allocation efficiency is improved, but signaling overhead increases
Solution Approach 1:
The patent makes the buffer status reporting mechanism universal by designing it to serve multiple functions: it provides information for grant allocation, enables UL starvation avoidance, and supports token bucket management. This multi-functionality reduces the need for separate signaling mechanisms, thereby improving resource allocation efficiency while minimizing additional signaling overhead.
3Measurement precision
If the WTRU reports buffer status information frequently, then grant allocation accuracy is improved, but signaling overhead increases
Solution Approach 1:
The patent implements dynamic buffer status reporting where the WTRU adjusts reporting frequency based on buffer conditions and grant allocation needs. This dynamic approach maintains high grant allocation accuracy by reporting when necessary while reducing signaling overhead by avoiding unnecessary frequent reports, thus resolving the contradiction between measurement precision and quantity of signaling.
Data Source
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AI summary
A method and apparatus for uplink (UL) starvation avoidance includes determining a current buffer status information. The current buffer status information is reported to an evolved Node B (eNB). A grant that includes a determination of a number of tokens a wireless transmit/receive unit (WTRU) may accumulate is received from the eNB.