Cascaded Polar-Convolutional Encoding for Better Decoding
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Solution Overview
Problem
The decoding performance of existing polar encoding methods needs to be improved to enhance data transmission reliability in communication systems.
Innovation Solution
A cascaded encoding method is introduced, where polar encoding is followed by convolutional encoding using a feedforward shift register, with specific conditions such as odd number of taps and initial bits being the last m bits of the sequence, to improve decoding performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polar encoding is used alone, then encoding complexity is low, but decoding performance is insufficient
Solution Approach 1:
The patent combines polar encoding and convolutional encoding into a cascaded encoding structure. The polar encoder first processes the input bit sequence to generate an intermediate bit sequence, which is then fed into a convolutional encoder. This merging of two encoding schemes allows the system to maintain the low complexity advantage of polar encoding while adding the error correction capabilities of convolutional encoding, thereby improving overall decoding performance without excessively increasing system complexity.
Solution Approach 2:
The patent creates a composite encoding scheme by integrating polar code and convolutional code. The polar code component provides polarization properties for reliable bit channel construction, while the convolutional code component adds redundancy and error correction capability. This composite approach leverages the strengths of both coding theories to achieve better decoding performance than either scheme could provide alone, while keeping the overall structure manageable through systematic design.
2Reliability
If convolutional encoding is added after polar encoding, then decoding performance is improved, but encoding complexity increases
Solution Approach 1:
The patent segments the encoding process into two distinct stages: a polar encoding stage that processes the input bit sequence to generate an intermediate representation, and a convolutional encoding stage that further processes this intermediate sequence. This segmentation allows each encoder to be optimized independently and enables modular implementation, where the convolutional encoder is added as a separate functional block after the polar encoder, making the complexity increase manageable and systematic.
3Reliability
If tail-biting convolutional encoding is used, then decoding reliability is improved, but implementation complexity increases
Solution Approach 1:
The patent implements tail-biting convolutional encoding by pre-configuring the shift register with specific initial states that match the final states of the encoding sequence. This preliminary setup of the shift register ensures that the encoding process starts and ends in a consistent state, eliminating the need for additional termination bits or complex state management during decoding. The initial state configuration is predetermined based on the encoding parameters, simplifying the overall implementation while maintaining the reliability benefits of tail-biting structures.
Data Source
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AI summary
An encoding method and apparatus are provided. The method includes: obtaining a to-be-encoded bit sequence (S401); performing polar encoding on the to-be-encoded bit sequence to obtain a first bit sequence (S402); performing convolutional encoding on the first bit sequence to obtain a second bit sequence (S403); and outputting the second bit sequence (S404). In the foregoing process, because convolutional encoding is cascaded after polar encoding, an encoding process of the to-be-encoded bit sequence is more adequate, and decoding performance can be improved.