Prioritized Retransmission of Lost Packets in Real-Time Streams
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Solution Overview
Problem
Current methods for retransmitting lost packets in real-time data streams, such as VoD services, are inefficient as they require additional bandwidth only when losses occur, leading to prolonged correction times and limited buffer memory capacity, which restricts the frequency and extent of loss correction.
Innovation Solution
Retransmitted packets are transmitted with priority over real-time packets at a lower transmission rate, allowing for accelerated retransmission and optimized buffer memory usage, enabling correction of larger losses or using smaller buffer sizes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If additional bandwidth is used to retransmit lost packets, then the retransmission speed is improved, but the buffer memory size must be increased to accommodate the retransmission process
Solution Approach 1:
The patent applies dynamic bandwidth allocation by switching between two transmission modes: normal mode for regular packet transmission and retransmission mode for lost packet correction. During retransmission, the system dynamically increases the transmission rate from the first bit rate to a second, higher bit rate, allowing faster correction of losses without requiring proportionally larger buffer memory.
2Loss of time
If the transmission rate is reduced during retransmission, then the retransmission time is shortened, but the overall data transmission efficiency decreases
Solution Approach 1:
The patent implements periodic switching between normal transmission and retransmission phases. During normal phases, data is transmitted at the first bit rate maintaining high efficiency. When losses are detected, the system switches to retransmission phases at a higher bit rate to quickly correct errors. This periodic alternation between the two modes optimizes both transmission efficiency and error correction capability.
3Reliability
If a larger buffer memory is used, then the capacity to correct losses is improved, but the system complexity and resource consumption increase
Solution Approach 1:
The patent changes the transmission rate parameter dynamically based on the operational mode. During retransmission, the system switches from the first bit rate to a second, higher bit rate. This parameter change allows the system to correct larger packet losses without increasing buffer memory size, as the higher transmission rate during retransmission phases compensates for the reduced buffer capacity.
Data Source
Figure 1~4B
Figure 2~3
Figure 5A~5B
AI summary
The invention relates to a method of sending a real-time data stream transmitted at a given bit rate (D1) in the form of packets between a sender (1) and a receiver (2) in a telecommunications network, characterized in that it comprises the following steps: - reception of a request for resending of lost packets; and - sending (E4) of resent packets (PP(i)) and of real-time packets, the resent packets being transmitted by priority with respect to the real-time packets.