Phase-Invariant Burst Coding for QPSK Rotation Ambiguity
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Solution Overview
Problem
Existing communication systems using short burst signaling face challenges in error correction and detection, particularly with rotational phase ambiguities in QPSK transmission systems, which can lead to errors in data recovery without a phase reference signal.
Innovation Solution
A phase invariant coding scheme using an extended binary Golay code is implemented, where 10-bit data is mapped into a 12-bit space, and parity data is generated to form a 24-bit code, with bit swapping to create I and Q data that are insensitive to rotational phase changes, allowing for error correction and data recovery regardless of phase rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional error correction schemes (repetition, parity, CRC, ECC) are used in short burst signaling systems, then error detection and correction capability is improved, but the systems remain vulnerable to rotational phase ambiguities in QPSK transmission without phase reference signals
Solution Approach 1:
The patent applies asymmetry by designing a coding scheme where the in-phase (I) and quadrature (Q) components are treated differently through bit swapping operations. The encoded bits are distributed asymmetrically between I and Q channels, and a specific bit swapping pattern is applied to create rotational phase invariance. This asymmetric treatment of I and Q components allows the system to correct errors regardless of rotational phase ambiguity, resolving the vulnerability of traditional symmetric error correction schemes to phase rotation.
Solution Approach 2:
The patent changes the parameter representation by transforming the traditional error correction approach into a phase-invariant coding scheme. Instead of using conventional parity or ECC bits that are sensitive to phase rotation, the system transforms the code structure so that the same information can be recovered from any rotational phase. The bit swapping operation and the specific mapping of data bits to I and Q components changes the parameter representation to be invariant under phase rotation, thereby eliminating the harmful effect of rotational phase ambiguity.
2Measurement precision
If phase reference signals are transmitted to eliminate rotational phase ambiguity, then data recovery accuracy is improved, but power consumption and system complexity increase
Solution Approach 1:
The patent extracts and eliminates the need for phase reference signals by embedding phase invariance directly into the coding scheme. Instead of adding separate reference signals to the transmission, the system takes out the dependency on phase reference by designing a code structure that is inherently invariant to phase rotation. The bit swapping and I-Q component distribution are designed so that the receiver can recover data accurately without requiring any additional phase reference information, thereby reducing power consumption and system complexity.
Solution Approach 2:
The coding scheme makes the system self-sufficient by enabling the transmitted signal to carry its own phase reference information implicitly. The phase-invariant structure allows the receiver to determine the correct phase alignment through the code structure itself, without needing external phase reference signals. The system serves its own phase synchronization needs through the inherent properties of the encoded signal, eliminating the need for separate phase reference transmissions and reducing overall power consumption.
3Reliability
If more redundant bits are added to improve error correction, then reliability is improved, but data transmission efficiency decreases
Solution Approach 1:
The patent achieves multi-functionality by designing a coding scheme that simultaneously provides error correction capability and rotational phase invariance within the same code structure. The bit swapping operation and I-Q component distribution serve multiple purposes: they create redundancy for error correction while also making the code invariant to phase rotation. This universal approach eliminates the need for separate phase reference signals and conventional error correction codes, thereby maintaining data transmission efficiency while achieving both error correction and phase invariance in a unified scheme.
Data Source
AI summary
An apparatus, system and method can be arranged for coding and/or decoding with a phase invariant coding scheme that is useful for short burst signaling devices. 10-bit data is mapped into a 12-bit data with a non-coherent burst code mapper. A parity generator creates a 12-bit parity data to form a 24-bit extended binary Golay code from the 12-bit data. The values for selected bit fields in the 12-bit data and 12-bit parity data are swapped to generate I and Q data such that sensitivity to changes in rotational phase is removed. I and Q data can be used by a transmitter to transmit a rotationally-invariant signal. On receipt, I and Q signals can be recovered, reverse swapped to generate the parity and data signals, and remapped to recover the transmitted 10-bit data. The receiver can also be arranged to use a soft decoding method for improved signal integrity.