A system comprising: a Radio Equipment, RE, (24, 62) configured to: - mix an uplink chirped sine wave signal and a predetermined uplink carrier frequency to provide an upconverted signal; - inject the upconverted signal into a radio frequency receive port of the RE such that the upconverted signal passes through a radio frequency interface (46, 76) of the RE to provide samples of the uplink chirped sine wave signal at an output of the radio frequency interface; and - transmit the samples of the uplink chirped sine wave signal from the RE to a Radio Equipment Controller, REC, (22, 60) on an uplink data path from the RE to the REC via an asynchronous communication network; and the REC being configured to: - receive a signal on the uplink data path via the asynchronous communication network comprising the samples of the uplink chirped sine wave signal transmitted from the RE to the REC on the uplink data path; - correlate a reference chirped sine wave signal and the samples of the received signal from the RE on the uplink data path via the asynchronous communication network; and - determine the uplink data path delay from the RE to the REC based on results of the correlation of the reference chirped sine wave signal and the samples of the received signal from the RE on the uplink data path. a Radio Equipment, RE, (24, 62) configured to: - mix an uplink chirped sine wave signal and a predetermined uplink carrier frequency to provide an upconverted signal; - inject the upconverted signal into a radio frequency receive port of the RE such that the upconverted signal passes through a radio frequency interface (46, 76) of the RE to provide samples of the uplink chirped sine wave signal at an output of the radio frequency interface; and - transmit the samples of the uplink chirped sine wave signal from the RE to a Radio Equipment Controller, REC, (22, 60) on an uplink data path from the RE to the REC via an asynchronous communication network; and - mix an uplink chirped sine wave signal and a predetermined uplink carrier frequency to provide an upconverted signal; - inject the upconverted signal into a radio frequency receive port of the RE such that the upconverted signal passes through a radio frequency interface (46, 76) of the RE to provide samples of the uplink chirped sine wave signal at an output of the radio frequency interface; and - transmit the samples of the uplink chirped sine wave signal from the RE to a Radio Equipment Controller, REC, (22, 60) on an uplink data path from the RE to the REC via an asynchronous communication network; the REC being configured to: - receive a signal on the uplink data path via the asynchronous communication network comprising the samples of the uplink chirped sine wave signal transmitted from the RE to the REC on the uplink data path; - correlate a reference chirped sine wave signal and the samples of the received signal from the RE on the uplink data path via the asynchronous communication network; and - determine the uplink data path delay from the RE to the REC based on results of the correlation of the reference chirped sine wave signal and the samples of the received signal from the RE on the uplink data path. - receive a signal on the uplink data path via the asynchronous communication network comprising the samples of the uplink chirped sine wave signal transmitted from the RE to the REC on the uplink data path; - correlate a reference chirped sine wave signal and the samples of the received signal from the RE on the uplink data path via the asynchronous communication network; and - determine the uplink data path delay from the RE to the REC based on results of the correlation of the reference chirped sine wave signal and the samples of the received signal from the RE on the uplink data path.