Single Code Rate With Multiple Modulation Schemes

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Solution Overview

Problem

Existing communication systems face challenges in efficiently transmitting multiple data streams due to varying channel conditions and signal-to-noise-and-interference ratios, which complicates rate selection and affects performance.

Innovation Solution

The use of a single code rate with multiple modulation schemes for multiple data streams, where channel estimates determine the selection of a single code rate and modulation schemes for each stream, simplifying encoding and decoding while improving performance by matching each stream's SNR to its required level.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If different code rates and modulation schemes are selected for each data stream to match varying channel conditions, then transmission performance is improved, but rate selection complexity and device configuration complexity increase

Engineering Contradiction:
Improvetransmission performanceVSAvoidrate selection complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by selecting different modulation schemes for different data streams based on their specific channel conditions (SNR levels), while using a unified code rate for all streams. This allows each stream to be optimized locally for its channel quality without requiring complex per-stream rate selection, thus improving transmission performance while controlling complexity.

Inventive Principle:
Principle #3Local quality

2Reliability

If independent rate selection is performed for each data stream based on varying SNRs, then transmission reliability is improved, but the amount of rate information to be transmitted increases

Engineering Contradiction:
Improvetransmission reliabilityVSAvoidrate information overhead
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The patent merges the rate selection by using a single code rate for all data streams while allowing different modulation schemes. This combining approach reduces the amount of rate information that needs to be selected and transmitted, as the code rate parameter is unified across all streams, thereby reducing information overhead while maintaining reliability through stream-specific modulation adaptation.

Inventive Principle:
Principle #5Merging (Combining)

3Adaptability or versatility

If multiple code rates and modulation schemes are used for multiple data streams, then adaptability to varying channel conditions is improved, but encoding and decoding complexity increase

Engineering Contradiction:
Improveadaptability to channel conditionsVSAvoidencoding and decoding complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by allowing different modulation schemes for different data streams to adapt to their specific channel conditions, while using a unified code rate for all streams. This provides adaptability to varying SNR conditions through modulation diversity while reducing encoding and decoding complexity by eliminating the need to handle multiple code rates simultaneously.

Inventive Principle:
Principle #3Local quality

4Reliability

If rate selection is performed for each data stream based on varying SNRs, then transmission performance is improved, but the time required for rate selection increases

Engineering Contradiction:
Improvetransmission performanceVSAvoidrate selection time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent merges the rate selection process by establishing a single code rate that applies to all data streams, while allowing modulation schemes to vary by stream. This unified approach significantly reduces the time required for rate selection compared to independent per-stream rate selection, as the code rate parameter needs to be determined only once rather than separately for each stream, while still maintaining performance through modulation adaptation.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP2866367B1Coding and modulation for multiple data streams in a communication system
Publication Date: 2018.12.26 QUALCOMM INC
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AI summary

Techniques for transmitting multiple data streams to a single receiver using a single code rate and different modulation schemes are described. Channel estimates are determined for the multiple data streams and used to select a single code rate and multiple modulation schemes for the multiple data streams. The system may support a set of code rates, and each code rate may be associated with a respective set of modulation schemes that may be used with that code rate. The single code rate for all data streams is selected from among the set of supported code rates, and the modulation scheme for each data stream is selected from among the set of modulation schemes associated with the single code rate. The multiple data streams are encoded in accordance with the single code rate. Each data stream is further modulated in accordance with the modulation scheme selected for that stream.