Packet Buffering for Mobile Backhaul PDV Reduction
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Solution Overview
Problem
Packet delay variation (PDV) in packet-based communication systems is a significant challenge, particularly in mobile backhaul networks, as it affects latency and synchronization accuracy, and existing solutions have limitations in minimizing PDV while maintaining low latency.
Innovation Solution
The method involves scheduling data packets into containers based on received inter-packet spacing to preserve this spacing, allowing for higher line rate output without introducing packet delay or loss, and using receiving apparatuses to adjust inter-packet spacing to compensate for PDV introduced by downstream network components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If statistical multiplexing and buffering are used in packet networks, then network flexibility and resource utilization are improved, but packet delay variation increases
Solution Approach 1:
The patent segments the packet transmission process into fixed time slots within superframes. Each time slot is allocated to specific traffic classes (real-time, buffered, best-effort), creating deterministic transmission paths that reduce packet delay variation while maintaining statistical multiplexing benefits for non-real-time traffic.
Solution Approach 2:
The patent changes the timing parameter structure by introducing fixed superframe periods and time slot allocations. This transforms the variable timing characteristic of traditional statistical multiplexing into a controlled hybrid approach where real-time traffic experiences fixed timing while other traffic utilizes statistical multiplexing within allocated slots.
2Productivity
If packets are buffered in packet switching nodes, then network resource utilization is improved, but latency becomes non-deterministic
Solution Approach 1:
The patent segments buffered traffic into different priority queues corresponding to different traffic classes. Real-time traffic is placed in high-priority queues with guaranteed transmission slots, while non-real-time traffic uses lower-priority queues, ensuring deterministic latency for time-sensitive applications while maintaining high resource utilization.
Solution Approach 2:
The patent implements continuous transmission of real-time traffic in dedicated time slots without interruption or re-buffering. This ensures continuous useful action for real-time data flows, eliminating variable latency caused by repeated buffering and forwarding decisions while maintaining overall network resource utilization through statistical multiplexing of other traffic classes.
3Manufacturing precision
If synchronous transmission is used, then packet delay variation is reduced, but network adaptability to varying traffic loads decreases
Solution Approach 1:
The patent applies different transmission qualities to different traffic classes within the same network infrastructure. Real-time traffic receives synchronous treatment with fixed time slot allocations and guaranteed bandwidth, while non-real-time traffic utilizes statistical multiplexing with variable allocation based on current network conditions, achieving both low PDV for critical traffic and high adaptability for overall network utilization.
Solution Approach 2:
The patent creates a universal transmission framework that can handle multiple traffic types with different requirements using the same physical infrastructure. The superframe structure with multiple traffic classes allows the network to function both as a synchronous system for real-time traffic and as a statistical multiplexing system for non-real-time traffic, providing multi-functionality and adaptability.
Data Source
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AI summary
An apparatus (301; 302; 303) for use in a packet-based communication system, comprises an input (30, 32) and an output (31). The apparatus (301; 302; 303) is configured to receive a stream of data packets, having an inter-packet spacing, and store the received data packets and information representing the inter-packet spacing in a buffer, wherein the data packets are no longer than a common maximum data- packet length. The apparatus (301; 302; 303) is further configured to schedule, at intervals, all the contents of the buffer except for a constant amount, into a respective container of a sequence of containers and, if the container then contains an incomplete data packet, schedule the remainder of the incomplete packet into the container. The apparatus (301; 302; 303) is further configured to send the sequence of containers, wherein the positions of the data packets within the containers depend on the received inter-packet spacing, and wherein the constant amount is equal to or greater than the common maximum data-packet length.