Golay Burst Coding for QPSK Rotational Phase 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 decoding ambiguities and errors.
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 rotationally invariant signal transmission and decoding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional error correction schemes (repetition, parity, CRC, ECC) are used in short burst signaling systems, then error detection and correction capability is provided, but rotational phase ambiguities in QPSK transmission still cause decoding errors and reliability deteriorates
Solution Approach 1:
The patent applies asymmetry by using the self-inverse property of the extended binary Golay code to create an encoding scheme where the transmitted signal and the decoded signal have an asymmetric relationship that is invariant to rotational phase. The code structure ensures that regardless of phase rotation, the decoded bits will always map back to valid codewords, eliminating phase ambiguity effects.
Solution Approach 2:
The patent changes the parameter of the error correction code from conventional schemes to the extended binary Golay code with specific parameters (23,12,7) or (24,12,8). This code parameter selection provides the mathematical property of self-inverse, which transforms the system's behavior to be rotationally invariant, thereby resolving the phase ambiguity problem.
2Reliability
If extended binary Golay code with bit swapping is used to achieve rotational invariance, then phase invariant decoding is achieved, but device complexity increases due to mapping and bit swapping operations
Solution Approach 1:
The patent applies preliminary action by pre-defining the bit swapping pattern and mapping scheme before transmission. The encoder pre-processes the data bits through the Golay code mapping with predetermined bit positions swapped, and the decoder uses the same pre-defined pattern to reverse the operation. This eliminates the need for complex real-time phase detection and correction during transmission.
3Reliability
If 10-bit data is mapped into 12-bit space with parity generation to form 24-bit code, then error correction capability is enhanced, but data transmission efficiency decreases due to increased redundancy
Solution Approach 1:
The patent changes the code rate parameter by using the extended binary Golay code with specific parameters (23,12,7) or (24,12,8). This provides optimal error correction capability for the given data rate, achieving the best balance between reliability and efficiency for short burst signaling applications.
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.