Wireless Channel Coding with Additional Parity Bits at Low Rates
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Solution Overview
Problem
Current channel encoding in wireless communication systems, particularly in 3G/4G and CIoT, faces performance degradation when the coding rate is ⅓ or lower due to limited power gain from repetition transmission, which does not achieve the coding gain achievable at decreased coding rates.
Innovation Solution
A method and apparatus for generating additional parity bits based on a required coding rate, allowing for efficient channel encoding and decoding at coding rates equal to or lower than a predetermined rate, by determining the number and positions of information bits to generate additional parity bits using single parity check codes, and incorporating these into codewords to support various coding rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If repetition transmission is used to achieve coding rate 1/3 or lower, then power gain is achieved, but coding gain is not achieved and system performance degrades
Solution Approach 1:
The patent segments the parity bits into two distinct sets: first parity bits generated by the rate 1/3 turbo encoder and second parity bits generated by additional encoding of information bits. This segmentation allows the system to obtain both power gain (through repetition of the codeword) and coding gain (through the additional second parity bits), resolving the contradiction by dividing the parity generation function into two specialized components.
Solution Approach 2:
The patent creates a composite coding structure by combining two different parity generation methods: the conventional turbo code parity (first parity set) and the additional parity bits generated through separate encoding. This composite approach merges the advantages of both methods, achieving both power gain from repetition and coding gain from the diversified parity structure, thereby improving system performance at coding rates of 1/3 or lower.
2Reliability
If coding rate is decreased to achieve better error correction, then coding gain increases, but system complexity increases
Solution Approach 1:
The patent introduces dynamic adaptability by allowing the transmitter to switch between two encoding modes: using only first parity bits when coding rate is above 1/3, and using both first and second parity bits when coding rate is 1/3 or lower. This dynamic adjustment optimizes the balance between error correction capability and system complexity based on channel conditions and required coding rates.
Solution Approach 2:
The patent changes the parameter of parity bit generation by introducing a conditional mechanism: when the required coding rate is 1/3 or lower, additional second parity bits are generated through parameter-based encoding of information bits. This parameter change allows the system to achieve better error correction capability only when necessary, avoiding unnecessary complexity improvement when it is not needed.
3Productivity
If additional parity bits are generated to meet coding rate requirements, then coding efficiency improves, but decoding complexity increases
Solution Approach 1:
The patent segments the decoding process into two independent parts: decoding of first parity bits using the conventional turbo decoder and decoding of second parity bits using separate parity check equations. This segmentation allows the receiver to process different parity bits through different decoding paths, improving coding efficiency while managing decoding complexity through specialized processing for each parity set.
Solution Approach 2:
The patent introduces an intermediary mechanism where the second parity bits serve as additional check bits that mediate between the information bits and the final decoded output. These second parity bits provide an additional layer of verification that improves coding efficiency without requiring complete redesign of the decoding architecture, as they can be processed through relatively simple parity check operations.
Data Source
AI summary
A method and apparatus for channel encoding and channel decoding in a wireless communication system are provided. The channel encoding method includes generating a first parity set and a second parity set based on information bits, determining a number of additional parity bits based on a number of the information bits and a required coding rate, generating the determined number of additional parity bits using the information bits, and generating a codeword including the information bits, the first parity set, the second parity set, and the generated additional parity bits.