Optical Relay Delay Estimation for 5G eCPRI Synchronization
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Solution Overview
Problem
Existing methods for measuring transmission delay periods in optical transport networks (OTN) are inadequate for 5G systems, as they rely on CPRI protocols that are not applicable to enhanced CPRI (eCPRI) used in 5G, leading to inaccurate time synchronization due to asymmetric delays.
Innovation Solution
A relay system and communication device configuration that includes optical transceivers and estimating units to measure transmission delay periods based on dispersion compensation amounts, specifying reception-related times, and determining accurate delay periods in uplink and downlink channels using eCPRI signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If CPRI protocol-based delay measurement methods are used, then the measurement process is simple, but the method is not applicable to 5G eCPRI systems and yields inaccurate results
Solution Approach 1:
The patent changes the measurement parameters from CPRI protocol-specific control codes to eCPRI-compatible dispersion compensation amounts and optical signal characteristics. By measuring transmission delay based on dispersion compensation values rather than protocol-specific timing markers, the system achieves compatibility with 5G eCPRI while maintaining measurement accuracy.
Solution Approach 2:
The patent replaces the mechanical/electrical CPRI protocol-based timing measurement with an optical-domain measurement approach. By using optical transceivers to measure dispersion compensation amounts directly in the optical signal, the system eliminates dependency on CPRI protocol structures and achieves eCPRI compatibility.
2Measurement precision
If asymmetric delay correction is not implemented, then the system operation is simple, but time synchronization accuracy deteriorates
Solution Approach 1:
The patent implements a feedback mechanism where transmission delay periods are continuously measured in both uplink and downlink directions, and the results are used to correct asymmetric delays. The optical transceivers provide feedback on dispersion compensation amounts, enabling dynamic adjustment of timing synchronization to maintain high accuracy despite asymmetric propagation delays.
Solution Approach 2:
The patent performs preliminary measurement of transmission delay periods using dispersion compensation amounts before actual data transmission. By pre-determining the asymmetric delay characteristics, the system can apply correction factors in advance, ensuring accurate time synchronization from the outset rather than reacting to synchronization errors.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables accurate measurement of transmission delay periods in 5G relay systems, correcting asymmetric delays and improving time synchronization accuracy.
Implementation Method 1
acquire, based on a dispersion compensation amount acquired by a first optical transceiver or a second optical transceiver, an estimated value of a transmission delay period
Data Source
AI summary
A relay system includes a first and a second communication device at least one of which includes an estimating unit that acquires, based on a dispersion compensation amount acquired by an optical transceiver, an estimated value of a transmission delay period, the transmission delay period being a period during which an optical signal is transmitted through an optical fiber; a specifying unit configured to specify, based on the estimated value of the transmission delay period acquired by the estimating unit, a transmission-related time which is related to transmission of a control code by the first communication device or the second communication device, or a reception-related time which is related to reception of the control code by the second communication device or the first communication device; and a determining unit configured to determine, based on the transmission-related time and the reception-related time, the transmission delay period in downlink or uplink channel.