imported>Chrisnait: Added {{Unreferenced}} tags (within {{multiple issues}}) tag to article (TW)

2020-03-13T22:02:46Z

Added {{Unreferenced}} tags (within {{multiple issues}}) tag to article (TW)

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{{Context|date=October 2009}}
{{Unreferenced|date=March 2020}}
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'''Synchronization Channel''' is a downlink only control channel used in [[GSM]] cellular telephone systems.
It is part of the [[Um air interface]] specification.
The purpose of the SCH is to allow the mobile station (handset) to quickly identify a nearby cell (a [[Base transceiver station|BTS]]) and synchronize to that BTS's [[Time division multiple access|TDMA]] structures.
Each radio burst on the SCH contains:
* the current frame clock of the serving BTS,
* the [[Base station identity code]] (or BSIC), a truncated form of cell identity, and
* an extended [[Training Sequence]] that is easily detected with a matched filter.
When mobile turns on after getting FCCH it waits for getting SCCH which is to synchronise mobile's oscillator frequency with the frequency of the Base channel.

The burst structure of the SCH is defined in GSM specification 05.03 section 4.7.
The encoding of the frame clock is defined in GSM specification 04.08 section 9.1.30.
The TDMA multiplexing pattern of the SCH is defined in GSM specification 05.02 clause 7 table 3.

The [[GSM]] Synchronization Burst Contains a '''Training Sequence''' of 64 bits that is used to facilitate synchronization.

* Sync bits are known by both the [[Base transceiver station|BTS]] and the mobile.
* Detecting where the synchronization burst occurs in time allows the [[mobile station|MS]] to synchronize with the [[Base transceiver station|BTS]] baud clock and frame clock.
* Tracking the drift from SCH burst to SCH burst can be used by the mobile station to fine-tune receiver clock.
[[Category:GSM standard]]

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Synchronization Channel - Revision history

imported>Chrisnait: Added {{Unreferenced}} tags (within {{multiple issues}}) tag to article (TW)