Downlink Flow Control via Resource Feedback
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Solution Overview
Problem
Long Term Evolution (LTE) wireless communication systems lack the ability to provide feedback from access terminals to base stations when resources are low, leading to potential overload and inability to handle peak instantaneous data rates, as existing flow control mechanisms like Radio Link Control (RLC) are not applicable in LTE.
Innovation Solution
Implementing a method for access terminals to generate and send control protocol data units (PDUs) or Channel Quality Indicator (CQI) reports to base stations based on resource utilization, allowing for dynamic adjustment of downlink data transmission rates to manage resource usage and prevent overload.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If access terminals are designed to handle peak instantaneous requirements of all applications, then they can handle peak data rates, but costs associated with access terminals significantly increase
Solution Approach 1:
The system dynamically adjusts the downlink data transmission rate based on real-time resource utilization feedback from the access terminal. The base station receives feedback about current resource usage and adapts the transmission rate accordingly, allowing the system to handle peak rates when needed while avoiding sustained operation at peak rates that would require expensive hardware over-provisioning.
Solution Approach 2:
A feedback mechanism is established where the access terminal monitors its resource utilization and sends feedback to the base station. This feedback loop enables the base station to adjust the downlink transmission rate to match the terminal's actual capacity, preventing overload while allowing peak performance when resources are available.
2Ease of manufacture
If access terminals are designed to handle common load conditions rather than peak instantaneous requirements, then costs are reduced, but they cannot handle peak data rates without overload
Solution Approach 1:
The system transitions from a static design approach to a dynamic one where the transmission rate is continuously adjusted based on feedback. This allows terminals to be designed for common load conditions while the system dynamically scales to handle peak rates when resources permit, without requiring terminals to be over-engineered for peak conditions.
Solution Approach 2:
The feedback mechanism enables the base station to recognize when the terminal can handle higher rates and adjust accordingly. The terminal reports resource availability, and the base station responds by modifying the transmission rate, allowing peak performance to be achieved when resources are available without requiring the terminal to be permanently capable of sustaining peak rates.
3Adaptability or versatility
If LTE systems use existing flow control mechanisms like RLC, then flow control can be implemented, but these mechanisms are not applicable in LTE
Solution Approach 1:
The feedback mechanism serves multiple functions: it provides flow control information, reports resource utilization status, and enables dynamic rate adaptation. This multi-functional approach implements flow control in LTE without requiring separate dedicated mechanisms, avoiding the complexity of adapting legacy RLC-based flow control to the LTE architecture.
Data Source
AI summary
Systems and methodologies are described that facilitate providing flow control feedback for controlling downlink data transmission rates. Various schemes can be utilized to send the flow control feedback from an access terminal to a base station. For example, a control PDU (e.g., MAC control PDU, PDCP control PDU) can be generated based upon a level of resource utilization of the access terminal, and sent to the base station for controlling the downlink data transmission rate. Following this example, a type of control PDU, a value included within the control PDU, etc. can be selected as a function of the level of resource utilization. By way of another illustration, a CQI report that includes a value selected as a function of the level of resource utilization associated with the access terminal can be generated and transmitted to the base station for controlling the downlink data transmission rate.