Adaptive Downlink Rate Control for Buffer Overflow Prevention
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Solution Overview
Problem
In emerging wireless communication systems like 3GPP LTE, buffer overflow occurs due to high downlink rates exceeding the processing capacity of subscriber stations, leading to data loss and re-transmissions, as conventional flow control signaling is delayed by time constraints in obtaining an uplink grant, and reducing maximum downlink rates compromises market competitiveness.
Innovation Solution
Implementing an additional capability parameter for an initial downlink rate and a reduced flow duration parameter to proactively manage downlink rates, allowing the system to initiate a lower initial downlink rate based on inter-processor communication link latency, thereby avoiding buffer overflow without immediate flow control signaling delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If buffer size of SS is increased to reduce buffer overflow occurrences, then buffer overflow is reduced, but cost of SS increases and marketplace competitiveness is reduced
Solution Approach 1:
The system performs preliminary action by proactively signaling flow control requirements before buffer overflow occurs. The SS identifies upcoming operations that will impact processing capacity and sends flow control messages in advance, allowing the BS to adjust downlink rates before the buffer fills up, thereby preventing overflow without needing large buffer memory.
2Reliability
If maximum downlink rate of SS is reduced to reduce buffer overflow occurrences, then buffer overflow is reduced, but marketplace competitiveness and performance are reduced
Solution Approach 1:
The system applies dynamics by making the downlink rate adjustable and adaptive rather than fixed. The BS dynamically modifies the downlink rate based on real-time flow control messages from the SS, allowing the rate to be high when processing capacity is available and low when operations are underway, thus preventing buffer overflow while maintaining high performance capability.
3Reliability
If conventional flow control signaling is used to reduce buffer overflow occurrences, then buffer overflow may be reduced, but delays in obtaining uplink channel prevent timely flow control signaling
Solution Approach 1:
The system performs preliminary action by identifying flow control requirements in advance and signaling them before the uplink channel becomes available. The SS prepares flow control messages ahead of time based on detected operations, and transmits them as soon as the uplink channel is granted, minimizing the effective delay and ensuring timely rate adjustment.
Solution Approach 2:
The system applies preliminary anti-action by proactively signaling the need for rate reduction before buffer overflow can occur. By detecting operations that will impact processing capacity and sending flow control messages in advance, the system prevents the harmful effect of buffer overflow before it can happen, rather than reacting after the buffer fills up.
4Reliability
If immediate flow control signaling is initiated upon receipt of data to reduce data transmission rate, then buffer overflow may be prevented, but flow control signaling is subject to delays in obtaining uplink channel
Solution Approach 1:
The system performs preliminary action by preparing and transmitting flow control messages as soon as the uplink channel is available, rather than waiting for buffer conditions to deteriorate. The SS proactively signals flow control requirements based on detected operations, ensuring the BS receives the information early enough to adjust the downlink rate and prevent buffer overflow despite uplink channel delays.
Data Source
AI summary
A technique for operating a wireless communication device includes transmitting a first downlink rate in a first control message. The first downlink rate is based on a latency of an inter-processor communication link associated with the wireless communication device. First downlink data at the first downlink rate is then received for a first time period. Following the first time period, second downlink data is received at a second downlink rate that is higher than the first downlink rate.