Hybrid HARQ Decoding for Portable Internet Terminals
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Solution Overview
Problem
Existing decoding methods in portable Internet systems face challenges in achieving high reliability and low error rates, particularly in varying channel environments, as conventional ARQ and FEC methods have limitations in throughput and reliability.
Innovation Solution
A decoding apparatus and method that selectively employs HARQ TYPE-I, HARQ TYPE-II, and HARQ TYPE-III schemes, along with symbol selection and channel decoding using chase-combining and code-combining schemes, to generate and retransmit subpackets with varying symbol orders and code rates, enhancing error detection and correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ARQ method is used, then structure simplicity and data reliability are improved, but throughput decreases rapidly as bit error rate increases
Solution Approach 1:
The patent combines ARQ and FEC into a hybrid ARQ system, merging the error-detecting and retransmission capabilities of ARQ with the error-correcting capabilities of FEC. This allows the system to maintain high reliability through retransmission while preserving throughput through forward error correction, resolving the contradiction between reliability and productivity.
Solution Approach 2:
The patent dynamically adjusts the code rate and combining schemes (chase combining, code combining) based on channel conditions and packet type. By changing these parameters adaptively, the system optimizes both reliability and throughput performance across varying bit error rates, preventing the throughput degradation that occurs with fixed ARQ parameters.
2Productivity
If FEC method is used, then throughput is preserved at predetermined level, but high reliability cannot be easily achieved
Solution Approach 1:
The patent merges FEC with ARQ in a hybrid system where FEC provides throughput preservation through error correction, while ARQ provides enhanced reliability through retransmission when needed. The combining of these two methods allows the system to achieve both high throughput and high reliability simultaneously.
Solution Approach 2:
The patent implements feedback mechanisms where the receiver sends acknowledgment signals to the transmitter based on error detection results. This feedback allows the system to switch between FEC-only mode (for good channel conditions) and HARQ mode (for poor channel conditions), optimizing both throughput and reliability based on real-time channel quality.
3Reliability
If HARQ scheme is used, then reliability and error rate are improved, but device complexity increases due to multiple combining schemes
Solution Approach 1:
The patent implements dynamic selection of combining schemes (chase combining vs. code combining) based on packet type, channel conditions, and code rate. The system transitions from static to dynamic operation, choosing the most appropriate combining method for each transmission scenario. This reduces the effective complexity by not implementing all possible combining schemes simultaneously, while still achieving high reliability through adaptive HARQ operation.
4Productivity
If conventional ARQ and FEC are combined, then throughput and reliability are improved, but selection flexibility according to channel environment is limited
Solution Approach 1:
The patent implements dynamic adaptation of HARQ parameters including code rate, combining scheme, and packet type based on real-time channel conditions. The system can switch between different combining methods and adjust error correction levels according to the current channel quality, providing high adaptability to varying channel environments while maintaining high throughput and reliability.
Data Source
AI summary
In a decoding apparatus in a portable Internet terminal, a channel encoded symbol received from a transmitter is decoded by one of a chase-combining scheme and a code-combining scheme selected based on an ID value of the subpacket indicating a start position of the symbol. In this case, the chase-combining scheme is partly used for the encoded symbol of the information bit. With such a mode, decoding can be performed at a low code rate.