Outer Coding with Shifted Parity Checks for Selective Retransmission
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Solution Overview
Problem
Current wireless communication systems face challenges in minimizing error rates and managing bursty interference in the coexistence of eMBB and URLLC scenarios, leading to decoding failures and increased complexity in H-ARQ processes.
Innovation Solution
The implementation of a cyclic shift parity check scheme that generates a shifted parity check code, allowing for error detection and correction without prior knowledge of failed code blocks, and using this code for retransmissions to reduce complexity and improve decoding success.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If H-ARQ retransmission is used with TB-based scheduling, then the complexity of network devices is reduced by limiting the number of concurrent H-ARQ processes to 8, but if the decoding of one FEC block within a TB transmission fails, the redundant versions of all the FEC blocks will have to be retransmitted even though some of the FEC blocks may have been correctly decoded
Solution Approach 1:
The transport block is divided into multiple code blocks, each with its own CRC check. The patent enables selective retransmission of only the failed code blocks by using outer coding to identify which specific blocks failed, rather than retransmitting the entire TB. This segmentation allows independent handling of each code block's retransmission status.
Solution Approach 2:
The patent introduces outer coding parameters (parity bits generated from multiple code blocks) to change the state of information available at the receiver. By adding these outer code parameters, the system can determine which specific code blocks failed and trigger selective retransmission, improving retransmission efficiency without increasing the number of H-ARQ processes.
2Adaptability or versatility
If bursty interference from coexistence of eMBB and URLLC scenarios occurs, then short transmission of URLLC packets may appear as bursty interference to eMBB transmission, but the failed decoding of such a code block leads to a decoding failure of the whole TB
Solution Approach 1:
The patent applies outer coding to generate redundant parity bits before transmission. These outer code parity bits serve as a cushion against bursty interference, allowing the receiver to detect and correct errors in individual code blocks without failing the entire TB. The outer coding provides a safety buffer that protects against the unpredictable nature of bursty interference from mixed eMBB and URLLC traffic.
3Productivity
If channel coding is used to detect and correct errors, then the throughput of the channel or link is improved by reducing the need to retransmit data, but the complexity of the coding and decoding process increases
Solution Approach 1:
The patent segments the error correction process into two layers: inner coding (FEC) applied to individual code blocks and outer coding applied across multiple code blocks. This segmentation allows the system to handle errors at the appropriate level, reducing the overall complexity compared to applying a single complex coding scheme to the entire transport block.
Solution Approach 2:
The outer code acts as an intermediary between the inner FEC codes and the retransmission process. It provides an additional layer of error detection and identification that enables selective retransmission, improving throughput by reducing unnecessary retransmissions while keeping the complexity manageable through its relatively simple parity bit generation and checking mechanism.
Data Source
AI summary
Embodiments relate to outer coding in communications between a first network device and a second network device. A transport block (TB) and a first parity code block that is based on contents of the TB are transmitted from the first network device to the second network device. The first network device receives feedback information that is transmitted from the second network device. The feedback information indicates a decoding failure of the TB. The first network device generates a second parity check CB that is based on the contents of the TB and is different from the first parity check CB and transmits the second parity check CB to the second network device. The second network device receives the second parity check CB and performs error detection decoding of the TB based on the second parity check CB.