LTE Modulation Adaptation for Receiver Complexity
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Solution Overview
Problem
In LTE communication systems, user devices that do not support high-order modulations like 64-QAM face challenges in achieving optimal data rates due to increased receiver complexity, latency, and power consumption, while also requiring efficient link adaptation to handle varying channel conditions.
Innovation Solution
The system chooses a modulation, coding, and rank scheme, and adds a detector class indicator to inform the capability for high-order modulation. If the high-order modulation is not supported, it substitutes with a lower-order modulation scheme providing similar performance, reducing computational load and power consumption by modifying lookup tables to include only QPSK and 16-QAM options.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-order modulation (e.g., 64-QAM) is used to increase data rate, then throughput is improved, but receiver complexity and power consumption increase
Solution Approach 1:
The patent applies parameter changes by dynamically selecting between different modulation orders (16-QAM and 64-QAM) based on channel conditions and receiver capabilities. The system changes the modulation parameter to optimize data rate while considering the trade-off with receiver complexity, allowing high-order modulation only when channel quality and receiver capability support it.
Solution Approach 2:
The patent implements dynamics through adaptive modulation where the modulation scheme is not fixed but dynamically adjusted based on real-time channel state information and receiver feedback. This allows the system to transition between 16-QAM and 64-QAM to achieve optimal performance under varying conditions, resolving the contradiction between data rate and complexity.
2Productivity
If high-order modulation (e.g., 64-QAM) is used to increase data rate, then throughput is improved, but power consumption increases
Solution Approach 1:
The patent uses parameter changes to dynamically adjust the modulation order based on channel conditions and power constraints. By changing the modulation parameter from fixed 64-QAM to adaptive selection between 16-QAM and 64-QAM, the system achieves higher data rates only when power consumption levels are acceptable, thus resolving the contradiction between throughput and power consumption.
Solution Approach 2:
The patent implements dynamic adaptation where the modulation scheme transitions between 16-QAM and 64-QAM based on real-time conditions including power availability and channel quality. This dynamic approach allows the system to maximize data rate when power is sufficient while consuming less power when channel conditions or power constraints require lower-order modulation.
3Adaptability or versatility
If link adaptation is implemented to optimize performance under varying channel conditions, then system adaptability is improved, but computational complexity increases
Solution Approach 1:
The patent applies parameter changes by adapting the modulation order parameter (16-QAM or 64-QAM) based on channel state information and receiver feedback. This parameter adaptation provides link adaptation capability to optimize performance under varying channel conditions while keeping the complexity manageable through a limited set of predefined modulation schemes and lookup tables.
Solution Approach 2:
The patent implements dynamic link adaptation where the system continuously adjusts the modulation scheme based on real-time channel conditions and receiver capabilities. This dynamic adaptation between 16-QAM and 64-QAM improves system versatility and performance optimization while maintaining acceptable computational complexity through efficient selection algorithms and pre-computed lookup tables.
Data Source
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AI summary
The invention relates to an apparatus comprising: at least one processor and at least one memory including a computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to: obtain a channel quality indicator comprising a detector class indicator informing transmitter's capability to a high order modulation, and substitute the modulation, coding and rank scheme utilising the high order modulation with a modulation, coding and rank scheme utilising a lower order modulation and providing nearest similar performance, if the high order modulation is not supported by a receiver.