Network Node Scheduler for CPRI Traffic Segmentation
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Solution Overview
Problem
Conventional packet networks are unsuitable for transporting CPRI traffic due to high latency, jitter, and asymmetry requirements, as they often suffer from Packet Delay Variation and asymmetry, making them unfeasible for fronthaul connections between Remote Radio Units and Digital Units in mobile networks.
Innovation Solution
A network node is configured with input and output ports and a scheduler that separates data packets destined for Remote Radio Units and Digital Units into distinct scheduling cycles, ensuring only data packets are transmitted in a first period, while other packets are transmitted in a separate second period, using fixed delays to maintain symmetry and avoid contention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional packet networks are used to transport CPRI traffic, then network versatility and ease of operation are improved, but latency, jitter, and asymmetry requirements cannot be met
Solution Approach 1:
The patent segments the packet network traffic into two distinct types: CPRI traffic (data packets between RRU and DU) and non-CPRI traffic (further packets). A scheduler is implemented to handle these different traffic types separately, ensuring that CPRI packets receive priority treatment with guaranteed latency bounds while non-CPRI packets are transmitted in remaining time slots. This segmentation allows the network to maintain versatility for multiple traffic types while ensuring reliability for time-sensitive CPRI communications.
2Device complexity
If CPRI traffic is transported over packet networks, then device complexity is reduced, but packet delay variation and asymmetry increase
Solution Approach 1:
The patent implements preliminary action by pre-calculating and storing timing information for CPRI packet transmissions. The scheduler is configured with advance knowledge of when CPRI packets should be transmitted, allowing it to proactively manage packet queues and ensure that CPRI packets are transmitted within their required time windows. This preliminary preparation prevents packet delay variation and asymmetry from occurring, while still allowing the system to use standard packet network infrastructure.
3Productivity
If data packets and further packets are transmitted in the same period, then transmission efficiency is improved, but contention among packets increases
Solution Approach 1:
The patent applies segmentation by dividing the transmission schedule into distinct periods: a first period dedicated exclusively to CPRI data packets and a second period for non-CPRI further packets. This temporal segmentation eliminates contention between the two traffic types while maintaining high transmission efficiency through dedicated resource allocation. The scheduler ensures that each period is fully utilized for its designated traffic type, preventing waste while avoiding conflicts.
Data Source
AI summary
A network node (15) is configured to switch data packets between a Remote Radio Unit (2) and a Digital Unit (4). The network node comprises one or more input port (33) configured to receive said data packets (52a) and receive further packets having a destination other than one of a Remote Radio Unit and a Digital Unit. One or more output port (35) is configured to transmit said data packets and said further packets. A scheduler (31) is configured to control transmission from the output port according to a scheduling cycle (41a). The scheduler is configured to schedule only said data packets to be transmitted in a first period of the scheduling cycle, and schedule one or more of said further packets to be transmitted in a separate second period of the scheduling cycle.