Adaptive Uplink Rate Control via Dynamic Bitrate Scaling
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Solution Overview
Problem
Current rate-based flow control mechanisms in HSDPA and EUL wireless communication systems are inefficient in adapting to sudden changes in transport network capacity, leading to congestion and unfairness among flows, as they rely on linear increase speeds that are too slow and lack multiplicative increase capabilities, which can cause instability and starvation.
Innovation Solution
Implementing a method in a Radio Base Station to control bitrate flow by setting an initial constant speed, detecting congestion, and increasing the bitrate flow by adding a linear increase rate factor, with periodic adjustments until a predetermined condition is met, while maintaining the Additive Increase Multiplicative Decrease (AIMD) property to ensure fairness and fast adaptation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If linear increase rate is used for flow control, then stability is maintained, but adaptation speed to network capacity changes is too slow
Solution Approach 1:
The patent applies dynamics by making the increase rate adaptive rather than fixed. The increase rate is dynamically adjusted based on the current bitrate and a scaling factor, allowing the system to transition from slow linear increase to faster multiplicative-like increase as capacity becomes available, thereby improving adaptation speed while maintaining stability through controlled adjustment.
Solution Approach 2:
The patent changes the parameter of increase rate from a constant linear value to a variable that scales with current bitrate and a scaling factor. This parameter transformation enables the system to achieve faster adaptation when network capacity increases by multiplying the increase rate appropriately, while still maintaining stability through the scaling mechanism that prevents excessive jumps.
2Adaptability or versatility
If multiplicative increase is used for flow control, then adaptation speed is improved, but fairness among flows deteriorates causing starvation
Solution Approach 1:
The patent implements feedback by continuously monitoring network capacity availability and using this information to adjust the increase rate. The scaling factor mechanism provides feedback control that prevents any single flow from monopolizing bandwidth by multiplying the increase rate excessively, thereby maintaining fairness while enabling faster adaptation when capacity is available.
Solution Approach 2:
The patent applies dynamics by making the increase rate adaptive rather than fixed. The increase rate is dynamically adjusted based on the current bitrate and a scaling factor, allowing the system to transition from slow linear increase to faster multiplicative-like increase as capacity becomes available, thereby improving adaptation speed while maintaining stability through controlled adjustment.
3Reliability
If timers are used to manage flow control states, then congestion detection is improved, but system complexity and latency increase
Solution Approach 1:
The patent applies self-service by enabling the flow control mechanism to automatically detect congestion and adjust rates without relying on external timers or complex state management. The multiplicative increase with scaling inherently provides self-regulating behavior that adapts to network conditions, reducing the need for timer-based control mechanisms and their associated complexity and latency.
Data Source
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AI summary
Method and arrangement in a radio base station for controlling the bitrate flow in a radio access network. The radio base station is comprised within the radio access network. The radio base station is adapted to control the bitrate flow of the incoming traffic to the radio base station. The method comprises detecting the occurrence of traffic congestion within the radio access network. The method also comprises resetting the increase rate to a constant speed if a traffic congestion has been detected. The method further comprises determining if a predetermined condition has been met. Further yet, the method comprises increasing the allowed bitrate flow of the incoming traffic to the radio base station, according to a predetermined bitrate increase factor.