# FCCH - Frequency Correction Channel FCCH is propagated by the BTS to syncronize the frequencies for downlink and Uplink. It negociate the ARFCN being used between BTS and Mobile Station. The Frequency Correction Channel (FCCH) is a special downlink channel used in GSM networks. It serves primarily to synchronize the frequency of the mobile station with that of the base transceiver station (BTS). When a mobile station is powered on, it initially listens for the FCCH to fine-tune its internal oscillator. This ensures that the mobile station's transmissions are aligned correctly to the network's frequencies, allowing for accurate signal reception and reducing interference. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://gsm.learn-telecom.com/gsm-channels/signalling-channels/broadcast-channels/fcch-frequency-correction-channel.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.