feel free to plagiarize the content

1. GSM Channels
Name: Utsav singh
Enrolment: 180140111103
Sub: Wireless Communication
prof: Khusboo J. Tailor

2. Outline
1. Classification of GSM channels
2. Full forms
3. Traffic channels and its details
4. Control channel and its details

3. Classification of GSM channels
There are two type of GSM channels, Logical and physical

4. Full forms

5. Traffic channels
• The traffic channels are intended to carry encoded speech or user data on
forward and reverse link.
• Formats and the frame structure used on both the links are identical.
• They can be further characterized into:
• Full rate traffic channels at a net bit rate of 22.8 Kb/s (TCH/F)
• Half rate traffic channels at a net bit rate of 11.4 Kb/s (TCH/H)

6. Control Channel (CCH)
• Control channels carry signaling information between an MS and a BTS.
• It is further divided into three parts:
• Broadcast control channel
• common control channels
• Dedicated Control Channels (DCCHs)

7. Broadcast control channel
• It forward control channel with time slot TS0 allocated to it.
• It is a simplex channel and can serve as a beacon channel to locate nearby device
• It provides synchronization for all MS in same cell
It is further divided into three parts:
• BCCH – cell and network identity, list of current engaged calls, congestion
• SCH – it provide signaling data useful for synchronization between MS and BS. When the MS is
far away >30km it is necessary to adjust clock timing to reduce timing errors.
• FCH – It occupies TS0 and repeats after every 10 frames and carries frequency information so
that mobile unit can synchronize its local oscillator’s frequency with BS frequency.

8. Common control channels
• It occupies TS0 of every GSM frame.
• It is necessary channel to establish/setup a call from MS.
It is further divided into three parts:
• PCH – it carrier information regarding the call originated from PSTN. BS to MS
• RACH – it is a reverse link carries acknowledgment messages and call requests
made from MS.
• AGCH – it is a message sent by BS before a subscriber is moved of the control
channel. It carries data that instruct mobile to operate in particular DCCH.

9. Dedicated Control Channels
• The DCCHs come into picture after a call is established. The dedicated control channel are
bidirectional
• They have same format and functions in the forward and reverse links
It is further divided into three parts:
• SDCCH – It guarantees the MS and BS will remain connected. resource allocation
• SACCH – it exchange control information during a call. i.e. transmit power level, received
signal strength measurement results from neighbouring cells.
• FACCH – urgent messages like handoff requests

10. Thanks