Reference Signal Sequence Design for GMSK Channel Estimation

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Solution Overview

Problem

The use of pseudo random sequences as pilot symbols in GMSK communication systems affects channel estimation accuracy, leading to poor channel estimation performance.

Innovation Solution

A reference signal sequence with exclusive OR of every two bits separated by one bit is designed, undergoing GMSK modulation and used for channel estimation, replacing pseudo random sequences.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If pseudo random sequences are used as pilot symbols in GMSK communication systems, then the system can operate with standard modulation techniques, but channel estimation accuracy deteriorates

Engineering Contradiction:
Improveease of implementationVSAvoidchannel estimation accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent changes the fundamental parameter of the reference signal from pseudo-random sequence to a specifically designed sequence with controlled bit transitions (maximum one bit change between adjacent symbols). This parameter change improves channel estimation accuracy while maintaining GMSK modulation compatibility

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies local quality by designing reference signal sequences with specific local properties (controlled bit transitions) rather than using globally random sequences. Each reference signal symbol is constructed to have at most one bit different from adjacent symbols, creating localized quality improvements in channel estimation

Inventive Principle:
Principle #3Local quality

2Device complexity

If pseudo random sequences are used as pilot symbols, then sequence generation is simple, but channel estimation performance deteriorates

Engineering Contradiction:
Improvesequence generation complexityVSAvoidchannel estimation performance
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent changes the generation approach from pseudo-random to deterministic sequences with controlled transition properties. The new sequence type (e.g., 00110011... or 01010101...) is generated through simple repetition or inversion operations rather than complex pseudo-random generation, maintaining low complexity while improving reliability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent inverts the conventional approach by not using random sequences but instead using highly structured, predictable sequences. The reference signal sequence is designed to be the opposite of pseudo-random - fully deterministic with controlled bit patterns that ensure at most one bit changes between adjacent symbols

Inventive Principle:
Principle #13The other way round (Inversion)

Data Source

PatentEP3267706B1Reference signal sending and receiving method and device
Publication Date: 2020.08.05 HUAWEI TECH CO LTD
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  • EP3267706B1 patent drawingFigure 7~9

AI summary

Embodiments of the present invention provide a reference signal sending method, a reference signal receiving method, and an apparatus. A reference signal sending method includes: obtaining a reference signal sequence, where the reference signal sequence includes multiple bits and exclusive OR of every two bits separated by one bit in the multiple bits is 1; performing Gaussian Minimum Shift Keying GMSK modulation on the reference signal sequence; and sending a modulated reference signal sequence. In the embodiments of the present invention, a reference signal sequence is designed as a sequence in which exclusive OR of every two bits separated by one bit is 1, GMSK modulation is performed on the reference signal sequence, and the same reference signal sequence is used to perform channel estimation during GMSK demodulation. Compared with a case in which a pseudo random sequence is used as a pilot symbol, channel estimation accuracy is improved, and channel estimation performance is further improved.