FEC and ARQ Hybrid Retransmission Control
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Solution Overview
Problem
Current wireless communication systems face challenges in efficiently managing errors in data transmission over wireless channels, particularly when Forward Error Correction (FEC) schemes are used, as they often require additional resources and do not allow for flexible handling of packet losses, making it difficult to optimize retransmissions in Point-to-Multipoint (PTM) transmissions.
Innovation Solution
Implementing a method where network nodes in wireless networks create repair streams corresponding to source streams, transmit packets as protocol data units, and control retransmissions based on feedback information, only initiating retransmissions when the FEC scheme is unable to compensate for losses, thereby optimizing the use of resources and reducing the need for individual retransmissions in PTM transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Forward Error Correction (FEC) schemes are used to protect against data losses, then reliability of data transmission is improved, but resource overhead increases and flexibility in handling packet losses deteriorates
Solution Approach 1:
The patent applies partial action by selectively enabling retransmissions only when necessary - specifically when FEC cannot compensate for losses. The network node determines whether retransmission is needed by checking if the number of lost packets exceeds the FEC correction capability, thus avoiding unnecessary retransmissions and optimizing resource usage.
2Adaptability or versatility
If FEC schemes are used to allow packet losses, then flexibility in handling errors is improved, but the ability to compensate for multiple packet losses deteriorates
Solution Approach 1:
The patent implements feedback mechanisms where the receiving device sends acknowledgments (ACK/NACK) to the network node about received packets. The network node uses this feedback to determine whether retransmission is necessary, creating a closed-loop system that adapts to actual channel conditions and packet loss patterns.
3Reliability
If multiple copies of data are sent using multiple streams, then reliability is improved, but resource usage increases
Solution Approach 1:
The patent applies partial action by sending repair packets only when needed for FEC reconstruction, rather than continuously sending multiple complete copies. The system dynamically adjusts the amount of redundancy based on actual packet loss conditions and FEC capabilities.
Data Source
AI summary
For a source stream of input data where FEC scheme(s) have been used to create a repair stream, transmitting by a network node packet(s) comprising data of the source stream or the repair stream packaged as at least part of PDU(s). An ARQ or HARQ process is applied to the PDU(s). The network node receives feedback information as part of the process corresponding to the PDU(s), including positive ACK/NACK response for the PDUs. The retransmissions of the negatively acknowledged PDU(s) are controlled when the FEC scheme is known not to be able to compensate for loss(e)s of packet(s) contained in the PDU(s) indicated as being negatively acknowledged. A UE receives packet(s), determines loss(es), and, in response to a determination the FEC scheme is known to be able to recover from the loss(es), sends at least one ACK for any lost packets that correspond to the one or more loss(es).