Relay Node Flow Control via Dynamic Buffer Status Reporting
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Solution Overview
Problem
In wireless communications systems, relay nodes face challenges with congestion and buffer management, leading to data loss and inefficient resource utilization, particularly in Long Term Evolution - Advanced (LTE-A) networks, where relay nodes need to balance buffer memory requirements with the need for multi-user diversity scheduling.
Innovation Solution
A system and method for relay node flow control and congestion management that involves determining buffer status and transmitting this information to a communications controller to adjust network resource allocation dynamically, optimizing data throughput and resource utilization by distinguishing between full and empty buffer states or using multi-bit thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the relay node buffers more downlink data for multiple UEs to enable effective multi-user diversity scheduling, then the scheduling effectiveness and data throughput are improved, but the buffer memory requirements increase, leading to higher cost, power consumption, and physical size
Solution Approach 1:
The patent implements dynamic buffer status reporting where the relay node monitors buffer occupancy levels and only reports to the donor eNB when buffer status changes occur (e.g., when buffer becomes full or empty). This dynamic approach allows the system to adapt resource allocation in real-time, maintaining high throughput when buffers are healthy while reducing unnecessary signaling when buffers are stable, thereby improving productivity without requiring excessive buffer memory capacity.
Solution Approach 2:
The patent establishes a feedback mechanism where the relay node reports buffer status information to the donor eNB, which then adjusts downlink resource allocation accordingly. When the relay node's buffer is full, the donor eNB reduces or suspends downlink transmissions to prevent data loss. This feedback loop enables the system to maintain high throughput during normal operation while preventing buffer overflow, thus resolving the contradiction between maintaining high productivity and minimizing buffer memory requirements.
2Productivity
If the relay node uses multi-user diversity scheduling to prioritize transmissions based on channel conditions and QoS, then the data throughput and resource utilization are improved, but the buffer management complexity increases
Solution Approach 1:
The patent segments the buffer management by implementing separate uplink and downlink buffers at the relay node, with independent status reporting mechanisms for each direction. This segmentation simplifies the overall buffer management complexity by allowing independent optimization and control of UL and DL buffer operations, while still enabling multi-user diversity scheduling across both directions to maintain high resource utilization.
3Reliability
If the relay node stops scheduling uplink transmissions when a UE's buffer becomes full, then data loss is prevented, but the pool of UEs available for multi-user diversity scheduling decreases, reducing throughput
Solution Approach 1:
The patent implements feedback mechanisms where UEs report their buffer status to the relay node, which then adjusts scheduling decisions accordingly. When a UE's buffer is full, the relay node temporarily suspends scheduling for that UE to prevent data loss, but continues to schedule other UEs with available buffers. This feedback-driven selective scheduling maintains reliability by preventing data loss while preserving productivity by keeping the scheduling pool active with available UEs.
Data Source
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AI summary
A system and method for relay node flow control and/or congestion control in a wireless communications system are provided. A method for relay operation includes determining a buffer status of a buffer for data to be transmitted on a communications channel allocated from network resources controlled by a communications controller, computing buffer status information based on the buffer status, and transmitting the buffer status information to the communications controller.