Adaptive Multi-Carrier Modulation BER Adjustment
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Solution Overview
Problem
Existing multi-carrier systems face challenges in accurately achieving a target Bit Error Rate (BER) across subcarriers, often resulting in subcarriers having either lower or higher BERs than desired, leading to inefficiencies in data transmission.
Innovation Solution
A method that determines channel quality values for each subcarrier, establishes ordered assignment groups, and assigns transmission parameters based on calculated link performance values to achieve precise BER targets, with adjustments made dynamically to ensure accurate link performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a simple SNR range mapping to modulation schemes is used, then the target BER is guaranteed, but the achieved overall BER value may be far from the target BER
Solution Approach 1:
The patent implements a feedback mechanism where the calculated overall BER is continuously compared with the target BER, and the SNR thresholds are dynamically adjusted based on the deviation. This closed-loop control allows the system to maintain the target BER while achieving precise overall BER values, resolving the contradiction between guaranteed reliability and measurement precision.
Solution Approach 2:
The patent dynamically changes the SNR threshold parameters based on the calculated overall BER performance. By adjusting these parameters in real-time according to actual channel conditions and BER measurements, the system achieves both reliable target BER guarantee and precise overall BER accuracy, eliminating the need for fixed threshold mappings.
2Productivity
If averaging over several subcarriers is carried out to improve SNR thresholds, then throughput increases, but the target BER is not achieved with desired precision
Solution Approach 1:
The patent uses feedback from actual BER measurements to adjust SNR thresholds dynamically. This allows the system to maintain high throughput by adapting to real-time channel conditions while achieving precise target BER values, resolving the contradiction between productivity and measurement precision that exists in static threshold approaches.
Solution Approach 2:
The patent transitions from static SNR thresholds to dynamic thresholds that adapt based on calculated overall BER performance. This dynamic adjustment mechanism enables the system to optimize both throughput and BER precision simultaneously by responding to actual channel conditions rather than relying on fixed averages.
3Reliability
If subcarriers with low SNR are assigned robust modulation schemes, then reliability is improved, but overall throughput is reduced
Solution Approach 1:
The patent applies local quality by assigning different modulation schemes to different subcarriers based on their individual SNR values and channel conditions. Each subcarrier receives the most appropriate modulation scheme for its specific conditions, allowing low-SNR subcarriers to maintain reliability while high-SNR subcarriers maximize throughput, thus resolving the contradiction between local reliability and overall productivity.
Data Source
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AI summary
The present invention relates to the fields of adaptive multi-carrier data transmission schemes. The present invention especially relates to a method of adapting transmission parameters of a group of subcarriers, a software program product and a communication device. The method of adapting transmission parameters of a group of subcarriers comprises steps of: determining a channel quality value for each subcarrier; establishing an order of assignment groups, each assignment group comprising one or more subcarriers, based on the channel quality values; assigning, in the order of the assignment groups, a transmission parameter to every assignment group, whereby assigning a transmission parameter to an assignment group comprises assigning the transmission parameter to all subcarriers of the assignment group; and calculating a link performance value based on previously assigned one or more transmission parameters; whereby the step of assigning a transmission parameter to every assignment group is based on the calculated link performance value.