Network Equipment Sliding Window Packet Resending

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Solution Overview

Problem

Existing network protocols, such as TCP, are not optimized for real-time data delivery, leading to inefficiencies in video streaming where data segments may be delivered after their processing and rendering time has expired.

Innovation Solution

Implementing a method at network equipment to set an expiration time for the initial payload of each data segment, allowing for the resending of segments with new payloads from subsequent segments when the expiration time is reached without acknowledgment, thereby optimizing data delivery in real-time applications.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If TCP protocol is used to ensure reliable delivery of data packets, then data accuracy and order are improved, but delivery timeliness deteriorates because retransmissions may occur after the data has expired

Engineering Contradiction:
Improvedata delivery reliabilityVSAvoiddelivery timeliness
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by setting an expiration time for each data packet before transmission. The network equipment proactively determines when a packet will become obsolete and uses this information to make intelligent retransmission decisions, rather than relying solely on TCP's reactive timeout mechanism. This allows the system to prepare for potential expiration issues in advance.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the parameter of packet handling by introducing expiration time as a new dimension for decision-making. Instead of only considering whether a packet was lost or not, the system now factors in the expiration time to determine whether to attempt retransmission. This parameter change enables the system to balance reliability and timeliness dynamically.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If TCP retransmission mechanism is used to ensure all data is delivered, then data completeness is improved, but bandwidth efficiency deteriorates due to retransmission of obsolete data

Engineering Contradiction:
Improvedata completenessVSAvoidbandwidth efficiency
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent implements feedback by continuously monitoring packet acknowledgment status and comparing it against expiration times. When a packet is not acknowledged within its expiration time, the system uses this feedback to determine whether to attempt retransmission. This feedback loop prevents wasted bandwidth on packets that will never be used, while still ensuring delivery of packets that may be needed.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent applies discarding and recovering by selectively dropping packets that have expired and cannot be delivered in time, while recovering the ability to retransmit only those packets that are still valid. This selective approach optimizes bandwidth by focusing retransmission efforts on packets that can still provide value, rather than attempting to recover all lost packets regardless of their expiration status.

Inventive Principle:
Principle #34Discarding and recovering

3Device complexity

If standard TCP timeout mechanism is used for retransmission, then protocol simplicity is maintained, but real-time performance deteriorates due to long timeout durations

Engineering Contradiction:
Improveprotocol simplicityVSAvoidreal-time delivery performance
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The patent segments the retransmission decision process into two independent components: the standard TCP timeout mechanism for determining packet loss, and a separate expiration time calculation for determining timeliness. This segmentation allows the system to maintain protocol simplicity while improving real-time performance, as each component can operate independently using its own criteria.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies preliminary action by calculating expiration times in advance based on the packet's intended delivery deadline. This preliminary calculation allows the system to make faster, more informed retransmission decisions without needing to implement complex new protocols. The expiration time is determined beforehand and stored with the packet, enabling quick comparisons during transmission.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3891949B1Network equipment and method for delivering data packets
Publication Date: 2025.05.21 INTERDIGITAL CE PATENT HOLDINGS SAS
  • EP3891949B1 patent drawingFigure 1~2
  • EP3891949B1 patent drawingFigure 3~4
  • EP3891949B1 patent drawingFigure 5~7

AI summary

During the delivery of a sequence of packets from a server to a client device, when an expiration time associated with an initial payload of a data packet belonging to a sliding window for delivery is reached without reception of a corresponding acknowledgment from the device, the server (300) resends the data packet with a new payload corresponding to the initial payload of a next data packet to be transmitted through the sliding window.