Samsung SGH 600, Service Manual

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1-2 Samsung Electronics
General Description
1-1-5 Logical Channel
TCH (Traffic CH) is used mainly for transferring the speech information, and the BCH (Broadcast CH) is
related to control information.The major function of BCH is transferring information on the downlink for MS
synchronization, identification, paging, and controll. BCH is always radiated from every cells and the MS tries
to find the BCH which has highest level soon after turned on. The organization of BCH is shown belows;
FCCH (Frequency Correction Channel), SCH (Synchronization Channel), and BCCH (Broadcast Control
Channel). CCCH (Common Control Channel) will play a role like a message board, and is divided into two
control channels - PCH (Paging Channel) and AGCH (Access Grant Channel). SACCH (Slow Associated
Control Channel) exists every 12 frames, controlling and controls the TX power level and timing advance of
MS, transferring cell information to MS on downlink, transferring the information about RX level, Quality, and
RX level of adjacent cell on uplink. FACCH (Fast Associated Control Channel) steals and changes the TCH
when needing a Handover. SDCCH (Stand-alone Dedicated Control Channel) and RACH (Random Access
Channel) operate during the call setup procedure.
1-1-4 GSM TDMA Timeslots, Frames, and Multiframes
0 1 2 3 4 ... ... ... ... ... ... 24 25
TCH
Multiframe
0 1 2 3 4 ... ... ... ... ... ... 49 50
0 1 2 3 4 5 6 7
BCH
Multiframe
TDMA
Frame
T Information F Midamble F Information T Guard
Timeslot
< Fig. 2 Concept of Frames and Timeslots >