Asymmetric Network Time Synchronization via Packet Interval Analysis
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing network synchronization methods, such as using GPS receivers or round-trip delay calculations, are inadequate for asymmetric networks with multiple links of varying upload and download speeds, leading to imperfect time synchronization and call quality degradation during handovers between femto and Wibro base stations.
Innovation Solution
A method and apparatus for analyzing packet intervals in asymmetric networks, using a look-up table to identify links by interpreting distribution of sampled packet intervals, and performing time synchronization based on the delay asymmetry ratio between uplink and downlink, enabling accurate synchronization even in networks with different link speeds and interfering packets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GPS receiver is mounted on femto cell base station to obtain accurate time information, then time synchronization accuracy is improved, but device cost and complexity increase
Solution Approach 1:
The patent uses packet timestamp information copied from the master node as a substitute for direct GPS reception. Instead of mounting GPS on each femto cell base station, the system copies time reference information through network packets, achieving synchronization without additional GPS hardware at each node.
Solution Approach 2:
The patent introduces packet timestamp information as an intermediary to transfer time synchronization data. Rather than direct GPS-to-base station connection, the timestamp acts as a mediator carrying time reference information through the network infrastructure.
2Measurement precision
If round-trip delay method is used to obtain time difference between base stations, then time synchronization is achieved, but measurement precision deteriorates in asymmetric networks
Solution Approach 1:
The patent segments the round-trip delay measurement into separate uplink and downlink component measurements. By measuring packet intervals in each direction independently and calculating the asymmetry ratio, the system adapts to asymmetric network conditions where upload and download speeds differ.
Solution Approach 2:
The patent changes the measurement parameters by introducing delay asymmetry ratio calculation. Instead of assuming symmetric delays, the system measures and compensates for asymmetry in packet transmission intervals between uplink and downlink directions.
3Measurement precision
If packet interval sampling is performed to analyze link configuration, then link detection accuracy is improved, but measurement time and complexity increase
Solution Approach 1:
The patent performs partial sampling of packet intervals rather than continuous monitoring. By sampling selected packets and using statistical analysis of the sampled data, the system achieves sufficient link detection accuracy without the overhead of exhaustive measurement.
Solution Approach 2:
The patent performs preliminary analysis of packet interval distributions to identify characteristic patterns before making link configuration determinations. This preliminary statistical characterization enables faster decision-making without requiring exhaustive measurement of all possible packet intervals.
Data Source
AI summary
Provided are an apparatus for and a method of analyzing a network, for example, an asymmetric network having a plurality of links, and a wireless device for use in the network. A method of analyzing a network having a plurality of links includes performing one or more operations of sampling a packet interval between two packets transmitted consecutively, and analyzing configuration of the plurality of links included in the network based on the one or more sampled packet intervals.