Link Adaptation Feedback via Estimated Packet Error Rate
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Solution Overview
Problem
In wireless communication systems, existing link adaptation methods face challenges in efficiently adjusting transmission parameters such as modulation and coding schemes and spatial streams to optimize throughput while maintaining low packet error rates, especially due to aged channel state information and varying channel quality.
Innovation Solution
A method where a receiver calculates and compares estimated packet error rates and throughputs for different modulation and coding schemes and spatial streams, adjusting parameters based on threshold comparisons and channel quality degradation assumptions to suggest optimal settings to the transmitter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the receiver calculates estimated packet error rates for multiple modulation and coding schemes to find optimal transmission parameters, then the system throughput is improved, but the feedback processing complexity and time consumption increase
Solution Approach 1:
The receiver pre-calculates estimated packet error rates for multiple modulation and coding schemes in advance, before actual transmission occurs. This preliminary calculation allows the transmitter to select optimal parameters based on pre-evaluated performance data, improving throughput while managing complexity through advance preparation
Solution Approach 2:
The receiver calculates packet error rates for more modulation and coding schemes than strictly necessary for basic operation. By evaluating a broader range of schemes including those beyond the currently used configuration, the system identifies optimal parameters more accurately, achieving better throughput at the cost of increased calculation effort
2Productivity
If the receiver calculates estimated packet error rates for higher order modulation and coding schemes, then the potential throughput increases, but the risk of packet errors increases due to aged channel state information
Solution Approach 1:
The receiver applies a degradation offset to the estimated packet error rate calculations to account for channel state information aging. This preliminary adjustment cushions against the increased error risk that would otherwise result from using outdated channel data to select aggressive modulation and coding schemes, thereby maintaining reliability while pursuing higher throughput
Solution Approach 2:
The system dynamically adjusts the degradation offset parameter based on the age of channel state information and current channel conditions. By modifying this parameter, the receiver can adaptively balance between selecting higher order modulation schemes for improved throughput and maintaining acceptable packet error rates, effectively managing the trade-off between productivity and reliability
3Adaptability or versatility
If the receiver sends frequent feedback to the transmitter to enable rapid link adaptation, then the system responds better to channel variations, but the feedback overhead and processing load increase
Solution Approach 1:
The receiver extracts and reports only the most critical link adaptation information to the transmitter, such as the recommended modulation and coding scheme index and spatial stream configuration. By selecting and transmitting only essential parameters rather than complete channel state data, the system achieves rapid adaptability while minimizing feedback overhead and information loss
Data Source
AI summary
A system and method for feedback for link adaptation. In some embodiments, the method includes: receiving, by a receiver, a first transmission from a transmitter; calculating a first estimated packet error rate, for a first modulation and coding scheme and a first number of spatial streams, the first modulation and coding scheme having a first modulation and coding scheme index; determining that the first estimated packet error rate is less than a threshold; and in response to determining that the first estimated packet error rate is less than the threshold, calculating a second estimated packet error rate, for a second modulation and coding scheme.