Delay Measuring Apparatus for CPRI Signal RTT Resolution
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Solution Overview
Problem
Conventional methods for measuring round trip time (RTT) in CPRI signals transferred via OTN frames have limited resolution, restricting accurate delay measurement due to the interval of OTU frames, resulting in insufficient measurement accuracy for CPRI delay measurements.
Innovation Solution
A delay measuring device that transmits and receives frames of known lengths, detects changes in RTT values, and determines the most accurate RTT value by adjusting transmission frequency or phase, and inserting empty bits to improve measurement resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If RTT measurement is performed using conventional OTN frame intervals, then the measurement method is simple, but the measurement resolution is insufficient
Solution Approach 1:
The patent applies dynamics by making the frame transmission frequency adjustable rather than fixed. The delay measuring device can dynamically change the frame transmission frequency to achieve different measurement resolutions. This allows the system to adapt the measurement granularity according to the required precision level, resolving the contradiction between measurement resolution and system complexity.
Solution Approach 2:
The patent changes the parameter of frame transmission frequency to improve measurement resolution. By varying the transmission frequency of frames with known lengths, the system can achieve finer RTT measurement resolution beyond the fixed OTN frame interval limitations. This parameter change enables high-precision measurements without requiring fundamentally new hardware.
2Measurement precision
If frame transmission frequency is increased to improve measurement resolution, then RTT measurement accuracy improves, but transmission time consumption increases
Solution Approach 1:
The system dynamically adjusts the frame transmission frequency based on the specific measurement requirements. When high resolution is needed, the frequency can be increased; when time is critical, the frequency can be reduced. This dynamic adaptation allows the system to optimize between measurement accuracy and time consumption for different operational scenarios.
Solution Approach 2:
The patent uses periodic frame transmission with known lengths to enable RTT measurement. By transmitting frames at controlled intervals and measuring the round trip time, the system achieves accurate measurements without requiring continuous high-frequency transmission. The periodic nature allows time-efficient measurement while maintaining accuracy.
Data Source
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AI summary
To provide a delay measuring device that can improve an RTT measurement resolution. A delay measuring device 1 of a communication system that includes the delay measuring device 1 sequentially transmitting and receiving frames having a known frame length, and a measurement object device 3 serving as an object for measuring a round trip time by the delay measuring device 1, comprises: an RTT measuring unit 17 to measure a round trip time with respect to the measurement object device 3 a number of times using information for delay measurement in the frame; an RTT change detection unit 18 to detect a change of a value of the round trip time based on the values of the round trip time thus measured; and an RTT determination unit 19 to determine a value of the round trip time to be adopted, from among the values of the round trip time, based on the change of a value of the round trip time.