Optical Delay Measurement Using Bypass Delay Compensation

The patent applies preliminary action by pre-calculating and inserting bypass delay information into the overhead before transmission. The first location inserts its bypass delay value into the overhead of multiframes it transmits to the second location, and the second location similarly inserts its bypass delay information. This preliminary preparation eliminates the need for complex real-time calculations at the receiving end, thereby improving measurement precision while managing device complexity through advance preparation.

The patent applies universality by making the overhead field serve multiple functions: it carries both traditional overhead information and the additional bypass delay information necessary for precise delay measurement. By utilizing existing overhead bytes (such as the PM&TCM byte) to transport bypass delay values, the system maintains compatibility with existing frame formats while enabling high-precision delay measurement. This multi-functional use of overhead resolves the contradiction between ease of manufacture and measurement precision.

The patent applies discarding and recovering by utilizing overhead bytes that would otherwise be unused or less critical for the primary data transmission function. By inserting bypass delay information into available overhead capacity (such as reserved or less priority bytes), the system recovers unused overhead resources for the purpose of delay measurement. This approach improves measurement precision while minimizing the loss of information efficiency, as the overhead bytes used for bypass delay are not critically needed for core data transmission.