Timing Packet Scheduling for Telecommunication Networks
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Solution Overview
Problem
In telecommunication networks, the accuracy of timing distribution is compromised by jitter and wander in packet delay variations, leading to bursts of timing packets that exceed the required phase accuracy for wireless protocols, potentially causing call quality issues and dropped calls.
Innovation Solution
A scheduling module determines packet transmission time offsets for timing packets based on unique identifiers or random spacing, spreading their transmission times to reduce the likelihood and length of bursts, thereby enhancing time distribution accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If timing packets are transmitted at regular intervals by multiple clients, then timing information is distributed to clients, but timing packets arrive in bursts at the server causing jitter and phase accuracy degradation
Solution Approach 1:
The patent applies preliminary action by having clients pre-calculate transmission time offsets based on their identifiers before actually transmitting timing packets. This pre-planned staggering of transmission times prevents packets from arriving in bursts at the server, thereby maintaining phase accuracy and reducing jitter without requiring real-time adjustments.
Solution Approach 2:
The patent changes the transmission time parameter by introducing identifier-based offsets that spread packet transmissions across different time slots. This parameter modification transforms the packet arrival pattern from concentrated bursts to distributed arrivals, resolving the contradiction between regular timing distribution and stable packet arrival patterns.
2Reliability
If Expedited Forwarding QoS policy is applied to timing packets, then timing packets are prioritized in queuing, but jitter still occurs due to multiplexing with other timing packets and lower priority data packets
Solution Approach 1:
The patent segments the transmission timeline into distinct time slots based on client identifiers, effectively dividing the shared network medium into dedicated transmission windows for different clients. This segmentation prevents multiplexing of timing packets from different clients, eliminating the source of jitter even when Expedited Forwarding is applied, while maintaining reliable timing packet delivery.
3Ease of operation
If store-and-forward media access techniques are used, then packets are received and queued before transmission, but large jitter is introduced for timing packets
Solution Approach 1:
The patent applies preliminary action by calculating and setting transmission time offsets before packets enter the queuing system. This pre-established timing schedule ensures that even when packets are queued using store-and-forward techniques, they are transmitted at predetermined staggered times, preventing the large jitter that would otherwise result from conventional queuing behavior.
Data Source
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AI summary
An apparatus and method of scheduling timing packets to enhance time distribution includes an improved apparatus in a system in which at least one of time and frequency information is derived based on information distributed in timing packets, at least some of the timing packets being transmitted by or received by the apparatus. The improvement includes a scheduling module that determines a first packet transmission time offset of a first timing packet based on a first predetermined identifier associated with the apparatus, and a second packet transmission time offset of a second timing packet based on the first packet transmission time offset and a timing packet spacing that is independent of the first predetermined identifier. The improvement further includes a transmission module that transmits the first timing packet based on the first packet transmission time offset, and the second timing packet based on the second packet transmission time offset.