Selective HARQ Retransmission Using LP-Decoded Non-Integral Bits
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Solution Overview
Problem
Current communications systems using HARQ for error control face inefficiencies in retransmitting data, as conventional methods often require high up-link capacity and may not effectively identify and retransmit only the necessary bits, leading to suboptimal throughput, especially at high signal-to-noise ratios.
Innovation Solution
Implementing a retransmission scheme that uses LP decoding and identification of non-integral bits to selectively request retransmission of specific bits or sub-blocks based on integrality checks, potentially combined with CRC verification, to reduce unnecessary retransmissions and optimize capacity usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional HARQ retransmission is used, then reliable data transmission is achieved, but up-link capacity is consumed and throughput is suboptimal
Solution Approach 1:
The patent segments the retransmission process by dividing data into transport blocks and further into bits, enabling selective retransmission of only erroneous bits rather than entire blocks. The identification unit divides the received signal into individual bit positions that can be independently evaluated for integrality, allowing granular error correction that minimizes up-link capacity consumption while maintaining reliability.
Solution Approach 2:
The patent applies local quality by making different parts of the data transmission process have different properties - correctly decoded bits are identified through integrality checks and excluded from retransmission, while only erroneous bits are retransmitted. This localized error correction approach optimizes throughput by avoiding unnecessary retransmission of correct data while ensuring reliable delivery of erroneous portions.
2Reliability
If conventional HARQ retransmission is used, then error control is achieved, but system throughput is reduced
Solution Approach 1:
The patent extracts only the erroneous bits from the complete data block for retransmission. The identification unit separates correctly decoded bits (those passing integrality checks) from erroneous bits, extracting only the problematic portions for retransmission. This extraction principle dramatically improves throughput by eliminating unnecessary retransmission overhead while maintaining error control through targeted correction of extracted erroneous bits.
Solution Approach 2:
The patent applies partial action by performing complete integrality checks on all bits but retransmitting only the partial set of erroneous bits identified. Rather than retransmitting entire transport blocks or using excessive redundancy, the system performs exactly the minimal necessary retransmission - only enough to correct identified errors - thereby optimizing throughput while ensuring reliable error control.
3Loss of energy
If selective retransmission of specific bits is implemented, then up-link capacity is optimized, but device complexity increases
Solution Approach 1:
The patent implements self-service through automatic integrality checks performed by the identification unit on received bits. The system automatically identifies erroneous bits through mathematical integrality verification without requiring complex external error detection mechanisms or extensive signaling protocols. This self-service approach optimizes up-link capacity by enabling selective retransmission while managing complexity through automated, algorithmic error identification rather than complex system architecture.
Solution Approach 2:
The patent changes the parameter used for error detection from conventional complex checksums or parity checks to simple integrality checks of decoded bit values. By transforming the error detection parameter to based on mathematical integrality properties of LP decoding results, the system achieves selective retransmission capability with reduced computational complexity, optimizing up-link capacity efficiency while keeping device complexity manageable through parameter transformation.
Data Source
AI summary
A method for retransmission of erroneous data in a communications system includes receiving data blocks at a receiver that have been generated in a transmitter by the use of an error correcting code. The received data blocks are decoded by a linear programming algorithm. One or more symbols in the decoded data block are identified by subjecting the symbols in the decoded data block to an integrality criterion. A retransmission of a part of the data block based on the one or more identified symbols is then initiated.